National Academies Press: OpenBook

Biographical Memoirs: V.76 (1999)

Chapter: Beno Gutenberg

« Previous: Maxwell Finland
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 114
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 115
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 116
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 117
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 118
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 119
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 120
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 121
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 122
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 123
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 124
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 125
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 126
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 127
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 128
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 129
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 130
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 131
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 132
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 133
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 134
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 135
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 136
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 137
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 138
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 139
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 140
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 141
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 142
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 143
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 144
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 145
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 146
Suggested Citation:"Beno Gutenberg." National Academy of Sciences. 1999. Biographical Memoirs: V.76. Washington, DC: The National Academies Press. doi: 10.17226/6477.
×
Page 147

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

BENO GUTENBERG June 4, 1889-January 25, 1960 BY LEON KNOPOFF BENO GUTENBERG WAS THE foremost observational seismolo- gist of the twentieth century. He combiner! exquisite analysis of seismic records with powerful analytical, inter- pretive, en c! mocleling skills to contribute many important discoveries of the structure of the solic! Earth en c! its atmo- sphere. Perhaps his best known contribution was the pre- cise location of the core of the Earth en c! the identification of its elastic properties. Other major contributions inclucle the travel-time curves, the discovery of very long-perioc! seis- mic waves with large amplitucles that circle the Earth, the identification of differences in crustal structure between continents en c! oceans, inclucling the discovery of a signifi- cantly thin crust in the Pacific, the discovery of a low-veloc- ity layer in the mantle (which he interpreter! as the zone of clecoupling of horizontal motions of the surficial parts from the creeper parts of the Earth), the creation of the magni- tucle scale for earthquakes, the relation between magnitudes en c! energies for earthquakes, the famous universal magni- tucle-frequency relation for earthquake distributions, the first density distribution for the mantle, the stucly of the tem- perature distribution in the Earth, the unclerstancling of microseisms, en c! the structure of the atmosphere. 115

6 BIOGRAPHICAL MEMOIRS Beno Gutenberg was born in ISS9 in Darmstacit, Ger- many, where his father own e c! a small soap factory. Beno was the elclest of two sons, his brother Arthur was his junior by four years. Both parents came from merchant families. His father's ambition was that Beno wouIc! step into the family business, as wouIc! his younger brother, but Beno wanted to study science, having little interest in the busi- ness. In the gymnasium he became involves! in the opera- tion of the meteorological station, en c! this arouser! an in- terest in weather forecasting en c! climatology, which lee! him to undertake meteorological studies at the university. In the summer of 1907 Gutenberg enterer! the Technische HochschuTe in Darmstacit. He learner! that a course on in- strumental observations of geophysical phenomena was be- ing offerer! by Emil Wiechert at the Institute of Geophysics of the University of Gottingen, en c! he mover! there in 1908. Wiechert hac! a major reputation in both seismology en c! electromagnetic theory. In the latter area, he is iclentifiec! with the Lienard-Wiechert potential. He proposed that X rays are electromagnetic waves, en c! from his measurement of e/m for cathode rays, he was the first to announce that cathode rays (electrons) are particles of subatomic mass from 2,000 to 4,000 times less massive than the hydrogen atom shortly before J. J. Thomson took the extra step of identifying the mass precisely. Wiechert was the inventor of a seismograph in wiclespreac! use in the first half of the twentieth century, en c! he hac! stucliec! the problem of con- structing the velocity structure of a spherical Earth from travel-times of seismic impulses, having derived an integral equation also iclentifiec! with the names of HergIotz en c! Bateman. Wiechert had also inferred that the Earth must have a central iron core. The four students in Wiechert's course were introclucec! into observational methods in meteorology, the handling

BENO GUTENBERG 117 of seismographs en c! the reacting of seismograms, en c! the determination of exact (astronomical) time. Gutenberg took lectures from Wiechert on terrestrial magnetism, ticles, en c! geodesy. He took lectures in physics, pure and applied math- ematics, elasticity, algebra, en c! logic from Born, Hilbert, Klein, E. Landau, Maclelung, Minkowski, PrancitI, Runge, K. SchwarzschiTcI, Voigt, en c! WeyI. Gutenberg took a course in geophysics to prepare better for his work in meteorology. At the enc! of a course in seismology in Gutenberg's thirc! year, Wiechert toic! him that he hac! progressed to the lim- its of knowlecige in seismology en c! acivisec! him to start his thesis research, Gutenberg selectee! a study of microseisms. In 1910 Gutenberg macle a trip to the coast of Norway, en c! was able to correlate surf in Norway with microseisms in Gottingen. Microseisms are small disturbances, more or less continuously recorclec! by sensitive seismometers, en c! form the backgrounc! motion upon which earthquake recordings are superimposed. As Gutenberg was later to discover, mi- croseisms are mainly associates! with storms in the creep oceans that are at times very distant from the recording station, en c! less so with surf. Gutenberg's first publisher! Caner, which was on microseisms, appearec! in ~ 9 ~ O. Gutenberg was concernec! with the problems of microseisms 1- 1- ' even at the enc! of his career. The possibilities of moclern instrumental seismology were not recognizec! until the enc! of the nineteenth century. IncleecI, the first recording of a distant earthquake was only macle on February 25, ISS9. So the time was ripe in the first decade of the twentieth century for a bright young investigator to attack the problems of the seismic wave ve- Tocity in the Earth's interior through the application of reacI- ings of high quality instrumental ciata. Like many of the prominent seismologists of the first half of the twentieth century, Gutenberg took up the subject without previous

8 BIOGRAPHICAL MEMOIRS intentions. He was attractor! by the opportunities for re- search in a comparatively new subject. One of Wiechert's assistants, Karl Zoppritz, hac! been con- cernec! with the calculation of the reflection en c! transmis sion coefficients of elastic waves. At about the time of Gutenberg's arrival in Gottingen, Zoppritz cliec! of a mas- sive infection at the age of twenty-seven. Wiechert passer! along an unfinished! manuscript by Zoppritz on the relation between the amplitucles of seismic waves en c! velocity varia- tions at depth, with the recommendation that the paper be finisher! by Gutenberg en c! Ludwig Geiger, who was Wiechert's other assistant. This event openec! the floor to a series of studies of the use of amplitucles of seismic waves to cleter- mine the structure of the Earth, Gutenberg's interest in amplitucles laster! throughout his career. Two papers on amplitudes by Geiger and Gutenberg ap- peared (1912) as part of the series "Uber Erdbenwellen" by Wiechert en c! his students. The two papers presented new results on the structure of the solid Earth determined from the amplitucles en c! travel-times of seismic waves. Geiger en c! Gutenberg attemptec! to determine the amplitucle-clis- tance relation for P-waves, but there are enormous fluctua- tions in the amplitucles from station to station, especially because of differences in instrumentation en c! in the local geology. Geiger en c! Gutenberg avoiclec! local influences by taking the ratio of amplitudes of PP/P (i.e., of waves with one bounce off the outer surface of the Earth to waves with no bounce). They observer! a large increase in the ratio at about 40° en c! 95°. The increase at 40° was attributer! to a decrease in the amplitucle of P. as was to be cliscoverec! later, the increase was actually clue to an increase in P at 20°, en c! hence of PP at 40°. An abrupt change of ampli- tudes with distance is a strong indicator of inhomogeneity in the velocity distribution at depth. Thus, Geiger and

BENO GUTENBERG 119 Gutenberg inferred that there was a significant decrease in the velocity gradient at a depth of about 1200 km in the mantle, instead of the more appropriate sharp increase in ~ · , , , · , ~ , ~ ~ ~ A ~ ~ , A A ~ ~ ~1 ~ gradient starhng at a depth ot around 41() to 44() km. 'l'he~r model had two additional discontinuous velocity gradients at depths greater than 1200 km. The increases in ampli- tudes at 20, called the 20 discontinuity, are today identi- fied with two steps in the properties of the mantle at depths around 410 km and 670 km. The decrease in velocity gradi- ent at about 1200 km and the absence of a sharp increase in velocity at shallower depths persisted in Gutenberg's models to the end of his career (1958), although the depth of the decrease was reduced to about 900 km in the later models. Indeed, Gutenberg (1934) stated, "There is no indication of a discontinuity in the mantle of the Earth at larger depths (than 200 km) . . . and none corresponding to an epicen- tral distance of about 20 " and again (1953), "There is no evidence of a discontinuity in the mantle between the low- velocity layer and a depth of about 900 km ...." Geiger and Gutenberg correctly interpreted the second increase in the ratio as due to a decrease in the amplitude of P. This was the onset of the shadow zone due to the decrease in seismic velocities in the core. ~. In 1 9 1~ Gutenberg submitted his dissertation on mi- croseisms entitled Die seismische Bodenunruhe (1912), written under the supervision of Wiechert. The oral exami- nation was held on May 3, 1911, and Gutenberg was awarded the degree of doctor of philosophy valde laudabiti, with geo- physics as his major and geometry and applied mathemat- ics as minor subjects. Wiechert's citation read, "The author has applied extraordinary diligence. About two million facts are used! The discussions are carried out with much skill, and the results are of considerable importance for science." Gutenberg worked in a postdoctoral capacity at the Insti

120 BIOGRAPHICAL MEMOIRS lute of Geophysics at Gottingen cluring the year following the aware! of his cloctoral degree. At that time he began his famous work of the systematic stucly of seismic waves through the interior of the Earth. From Gottingen recordings, he observer! that the seismic phase P hac! an increase of am- plitucles at a distance of about 143°. He extenclec! the range of amplitucles to greater distances, which allowed! him to interpret the shallow zone between 95° en c! 143° as cast by a low-velocity core at great depth in the Earth and of consid- erable contrast to the region above. In 1897 Wiechert hac! proposer! that the Earth hac! an iron core starting at a depth of about 1400 km, en c! in 1906 OIc~ham hac! interpreted seismographic ciata to propose that the core began at a depth of about 3900 km. Gutenberg calculated "the travel-times of waves to be reflected and refractec! at the surface of the core, outsicle as well as in- sicle", the waves refractec! at the core-mantle boundary are the P or PKP phases, en c! the reflected! waves are the PcP phases. Gutenberg cleterminec! the depth to the top of the core as 2900 km from the surface. He establishec! that the core has a sharp boundary and specified the values of the P-wave velocities in the mantle en c! in the core (1914~. To clo the calculation, Gutenberg clevelopec! new, accu- rate travel-time curves for both P- and S-waves for distances greater than 80°, which allowed him to determine the slope with high accuracy. His velocity distribution for the mantle was similar to the 1912 moclel. The precision of Gutenberg's determination of the depth to the core is astounding en c! would be so at any time. More than twenty years later, Gutenberg en c! Richter (1936) user! the times of the reflec- tions PcP from the upper surface of the core en c! clerivec! the same depth to the core boundary. In 1939 HaroIc! Affrays, using his powerful seismological en c! statistical skills in a calculation with his own travel-time data, derived the result

BENO GUTENBERG 121 2898 + 3 km, which is the value in common use tociay. Affrays also verifier! that the core-mantle boundary was sharp. Affrays notes! that, although his en c! Gutenberg's travel- time curves agree within one second, the first derivatives were significantly different, which was (anc! is) important, since the ratio of raclius to velocity r/v for the ray whose maximum penetration is to radius r is equal to the cleriva- tive of the time-angular distance relation. After the monu- mental discovery of the core, two major seismological plums of creep-earth structure remainec! to be cliscoverecI, namely Lehman's discovery of the inner core en c! Gutenberg's work on the absence of S-phases in the core. Gutenberg began a year of military service in October 1912. In October 1913 he starter! to work as a seismologist with the title of scientific assistant at the Central Bureau of the International Association of Seismology (IAS) at Strassburg, working on microseisms, travel-time curves, en c! the crustal structure of Europe. His work at Strassburg was interruptec! by the outbreak of Woric! War I in August 1914 after only ten months on the job. He was quickly incluctec! into the German army en c! servec! in the infantry. Almost immecliately, Gutenberg was wounclec! in the heat! by a gre- nacle (his helmet saver! his life). Upon recovery, he returnee! to Strassburg, where he was assignee! to the training of of- ficers. In 1916 he volunteerec! for the weather forecasting service en c! was sent to the Central Station for Meteorology near Berlin. Gutenberg shuttles! between the Russian, French, en c! Beigian fronts as a meteorologist attacher! to the chemical warfare engineers, having been assignee! the problem of the prediction of the likelihood! of backwarc! cirift onto the German soicliers of the poison gases that their own army hac! releasecI. He was also assignee! the problem of mea- surement of the location of cannons from the travel-times of sounc! transmission, a problem of great similarity to that

122 BIOGRAPHICAL MEMOIRS of the location of earthquake sources. His later work on the structure of the atmosphere (e.g., 1926, 1930) hac! its gen- esis at this time. During the war he spent as much time as possible at Strassburg en c! worker! on routine interpretation of seismo- grams at the Central Bureau in Strassburg uncler 0. Hecker. The IAS en c! the Central Bureau were clissolvec! on March 3l, 1916, en c! Gutenberg became scientific assistant for the Meteorological Service at the German Imperial Station for Earthquake Research at the University of Strassburg. He was concernec! with seismological problems cluring much of the war, meteorological work permitting. With the return of Alsace to France at the enc! of Woric! War I, Gutenberg was unemployocI, en c! he returnee! to Darmstacit. He was an applicant for his oIc! post at the now- French seismic station in Strasbourg, but he was not suc- cessful, even though he was soon to be the most famous seismologist in Western Europe. After the war, the German interior ministry placer! Gutenberg in an earthquake research institute that was planner! for {ena, but because of the chaos in postwar Germany, the institute existed only on paper. In 1923 Hecker was appointed to the {ena position, but the interior ministry couIc! not (or wouIc! not) appoint Gutenberg. (Gutenberg received a letter of greeting on the occasion of the thirtieth anniversary of the Jena Insti- tute aciciressec! to its long-time workers en c! colleagues that he consiclerec! to be a "wry joke.") Since he conic! not fine! a scientific position after the war, Gutenberg worker! in his father's soap factory in Darmstacit from ~ 9 1~ to ~ 930. Arthur hac! cliec! in the war in ~ 9 15 , en c! Beno was under some pressure to help with the family busi- ness. After his father's death in 1927, Beno took over the factory. He met Hertha Dernburg at activities of Jewish sport- ing and democratic clubs in Darmstadt. They were married

BENO GUTENBERG 123 on August 14, 1919. Gutenberg continues! to be active in local Jewish causes, en c! was a member en c! later president of the local chapter of B'nai Brith. From 1918 Gutenberg worked on geophysical problems at his home in Darmstacit, when he hac! free time, mainly cluring evenings en c! weekends. He user! seismographic re- corclings that were obtainer! from the institute at Frank- furt a long tram rifle away. He obtainer! recordings en c! other information from other observatories by correspon- clence. Starting in 1923, a stoutly stream of important pa- pers began to appear from his study in Darmstacit. In Der Aufbau derErde (1925) Gutenberg constructed! accurate travel- time curves for seismic waves in which all the important seismic phases were shown to IS0°, inclucling some phases triply reflected! from the surface. Gutenberg confirmed! en c! macle precise the observations of Tams, Angenheister, en c! MaceTwane in ~ 92 I-22, in which the velocities of propagation of surface waves were faster across the oceanic than across the continental portions of the Earth's surface (1924~. For this he user! measurements of the velocities of both Love en c! Rayleigh waves at a num- ber of periods from all the prewar seismographic records at Strassburg, from all records at Lena, en c! selectee! records from other stations. He proposer! a methoc! of inversion of the dispersion of surface waves to determine upper mantle structure that was similar to the methoc! ultimately applier! in the late 1950s. His inversion for crustal thickness (he manager! to confuse group en c! phase velocities) gave a thick crust uncler the continents en c! a thinner crust uncler the oceans, with a crustal thickness of only 5 km uncler the Pacific. The latter was a remarkably foresightfuT result in view of direct substantiation about thirty years later when exploration of the oceanic crust became possible. From these results, Gutenberg became convincer! that there were large

124 BIOGRAPHICAL MEMOIRS structural differences between continents en c! oceans in the outermost parts of the Earth, a view that was to play a sig- nificant part in his moclel of continental cirift (1936~. Be- cause of his observation of differences between continental en c! oceanic upper mantle structure, Gutenberg was con- vincec! of the likelihood! of horizontal mobility long before it became fashionable in the geophysical community. He began a study of the rheological problems associates! with Wegener's theory of continental drift en c! clevelopec! his own theory of flow in the mantle (1927~. Gutenberg was especially pleaser! with his calculation of the distribution of the density, en c! hence the elastic mocluli, as a function of depth in the Earth (1923~. The calculation may be consiclerec! crucle by tociay's stanciarcis, since it re- liec! on a linear clensit~versus-clepth moclel in each of the four layers in the mantle mocle! of 1912, but it is important, because it was the first construction of a density clistribu- tion for the mantle. Later, Bullen introclucec! the constraint of compressibility, en c! still later the density was obtainer! by Gilbert en c! Dziewonski en c! others from inversion of the free oscillation spectrum. This was the starting point for a new cliscipline concernec! with the chemical composition of the Earth's interior. In his later discussions of composition, Gutenberg relief! mainly on the density moclels of Bullen, BullarcI, en c! Birch, rather than his own. Gutenberg's unhappy financial situation clic! not escape the notice of Professor Franz Linke, director of the Insti- tute of Meteorology en c! Geophysics of the University of Frankfurt. Linke proposer! to Gutenberg that he obtain his Habititation, which was awarclec! at the University of Frank- furt on July 25, 1924, with his book Die seismische Bodenunrnhe as his Habititationsschrift. Although it hac! the same title as his thesis, the book presented new results on microseisms en c! the structure of the Earth. After an introductory lec

BENO GUTENBERG 125 lure with the title "New Results on the Structure of the Earth's Crust," he became privat-clozent, the equivalent of an instructor en c! hell! lectures in geophysics at the Univer- sity of Frankfurt from 1924 to 1930. He lecturer! on seis- mology, applied geophysics, oceanography, tides, and the structure of the Earth. The salary at Frankfurt was a per- centage of the tuition pair! by his students, but it was still insufficient to support himself en c! his family, en c! now he hac! the aciclitional workloac! of his numerous lectures. Dur- ing this period, Gutenberg en c! his wife clevotec! their full efforts to operation of the factory uncler hardship, in the immediate postwar perioc! they barterer! soap both for raw materials for their products en c! for personal necessities. His financial situation clic! not change significantly when, on October 2l, 1926, the science faculty of the University of Frankfurt electec! him to the position of ausserordentticher Professor, a non-state funclec! position, which he hell! from 1926 to 1930. The citation of the faculty in his election react, "It is not consonant with his scientific importance that Dr. Gutenberg has been a merchant-official in his father's soap factory in Darmstacit since the enc! of the war in order to support himself. Our faculty has conferred upon him the Habilitation on July 25, 1924. His lectures are clelights from semester to semester en c! attract more en c! more stu- clents. We fear that uncler this clouble life as merchant en c! scholar, his productivity will graclually disappear. It is un- likely that such productive scientific work as has appearec! in recent years from Dr. Gutenberg can persist for much longer if he continues to have his full-time merchant's re- sponsibility." Despite these concerns voicer! by the faculty, the profes- sorship was poorly funclec! en c! Gutenberg's stipenc! contin- ucc! to be clerivec! principally from his position as privat- clozent. Later he aciclec! a position as director of the

126 BIOGRAPHICAL MEMOIRS seismological station of the university, Tocatec! on the Kleine Felciberg in the Taunus mountain range on the opposite sicle of Frankfurt from Darmstacit. The two scientific posi- tions were still insufficient to support him en c! his family, which now incluclec! two chilciren. Gutenberg user! his stipenc! as director of the Kleine Felciberg station to start the publication of a bulletin. After working with the Galitzin pendulum seismographs, Gutenberg shower! no further direct interest in instrumentation, he was, of course, an avic! user of the recordings that conic! be obtainer! from the seismographs. Each year he spent two or three periods of one to two weeks each in the Taunus. He enjoyoc! the quiet, which enablec! him to think creatively in solitucle on his tinily, en c! occasionally twice tinily, walks to the peak. The path is now namer! "the Benoweg" in his honor. Gutenberg was invites! to the cleclication of the Benoweg in August 1959, a few months before cleath, but he clic! not attend. A number of well-known seismologists visitor! the house at MuhIstrasse 6 in Darmstacit, inclucling Inge Lehmann in 1926 en c! lames MaceTwane en c! Perry Byerly in 1929. Al- though Beno spent his clays at the factory, the visitors re- ceivec! his full attention in the evenings, on weekends, en c! in his spare time. Lehmann has states! that on the occasion of her visit with Gutenberg in 1926, they simply worker! together without any communication of a personal nature. She also states! that Gutenberg was a wonclerful teacher en c! that she owes! him her excellent introduction to seis- mology en c! that he gave of his time unselfishly. Her im- pression did not change when she visited Gutenberg in Pasa- dena. Contrary to the pessimistic forecast of the Frankfurt fac- ulty, Gutenberg continues! to turn out many papers en c! a remarkable series of books. The Lehrbuch der Geophysik (1929)

BENO GUTENBERG 127 was written en c! compiler! in the stucly of the house on MuhIstrasse. The Lehrbuch was a major undertaking that pro- viclec! a complete description of the unclerstancling of the geophysics of the solic! Earth, the oceans, en c! the atmo- sphere up to that time. The topics incluclec! evolution of the Earth en c! its geologic structure, volcanoes, mechanics of the atmosphere, en c! ice ages. There were nine contribu- tors, inclucling Linke en c! L. Weickmann. Gutenberg wrote a fourth of the volume, whose length exceeclec! a thousanc! pages. Interestingly, Gutenberg's bylines for his own chap- ters in the Lehrbuch are "B. Gutenberg, Darmstacit," while the title page en c! table of contents identify him as "B. Gutenberg, Frankfurt." It is clear that the massive undertaking of the Lehrbuch was a project clevelopec! almost completely from his home en c! that Muhistrasse 6 hac! become the center of German seismology en c! geophysics. Of special note in the Lehrbuch are remarks that appear on the conclucling pages, in which he speculates about the possibility of earthquake preclic- tion en c! Limits that the density of seismographs at the time was too small to allow for the collection of acloquate ciata to help with this question. Gutenberg's optimism was in sharp contrast to the pessimism of his later colleague Richter. Wiechert cliec! in March 192S, en c! Gutenberg was on the list to succeec! him at Gottingen. He also hac! hoper! to be the successor to Angenheister at Potsciam. But these hopes were not fulfi~lecI, en c! he still conic! not fins! a permanent, decently paying position, despite his Olympian reputation among geophysicists. There are indications that his Jewish backgrounc! playact a part in all this. IncleecI, Max Born remarkocI, in the case of the rejection of von Karman's cancliciacy, that there was concern over the number of Jews in the science faculty at Gottingen.

128 BIOGRAPHICAL MEMOIRS The Lehrbuch was a precursor to the even more monu- mental Handbuch der Geophysik, which was planner! to be a series of ten volumes. Gutenberg acceptec! en c! successfully carrier! forwarc! the ecliting of this daunting task. Although the job of ecliting the encyclopeclia was acceptec! before his departure for Pasadena in 1930, the work continues! after- warcI. The volumes appearec! in irregular order, I was un- able to locate volume 5, en c! it may not have been pub- lished. Volumes I, 2, 4, 6, 7, and part of volume 9 appeared between ~ 93 ~ en c! ~ 936. In ~ 937 the Nazis remover! his name from the enterprise. Although the editorship of vol- ume 3 (1940) was given to Weickmann, Gutenberg's chap- ters on forces in the Earth's crust en c! geotectonic hypoth- eses were not removed. Strangely, Gutenberg's bylines for these two sections in volume 3 identify him as being at Frankfurt, even though he hac! left for Pasadena ten years earlier. Linke's name appears as editor of volume S. The last part-volume to appear, volume S(3), did so in 1955, thirteen years after the appearance of the volume prececling it. It was a slencler en c! poor shallow of the ear- lier volumes. Clearly, without Gutenberg at the helm, the enthusiasm for the project hac! clissipatecI. Gutenberg con- tributed about 750 pages of text to chapters in volumes 2, 3, 4, en c! 9 between 1932 en c! 1940. In 1921 the Carnegie Institution of Washington initiates! studies in seismology at its Mount Wilson Observatory labo- ratory in Pasadena in cooperation with the California Insti- tute of Technology. Laboratory director H. O. Wool! with the concurrence of I. C. Merriam, president of the Carnegie, focuses! on unclerstancling California earthquakes. Woocl's scientific interests were mainly in instrumentation user! to locate epicenters of earthquakes in southern California, faults then could be identified and statistics of local earthquakes could be constructed so that they might contribute to the

BENO GUTENBERG 129 prediction of strong earthquakes. To clo this he hac! con- structec! a small but effective network of iclentical seismo- graphs of his own design. The network was inaugurate! in 1923 with Pasadena as the focal station. In 1927 the Carnegie activity in seismology was mover! to a new Seismological Laboratory that hac! been built by Caltech. By 1929 it was clear that the Carnegie program clivergec! from the directions that R. A. Millikan en c! the Caltech faculty thought important, which was that seismo- Togical studies shouic! aciciress global as well as regional prob- lems. After all, conic! not the growing collection of records of near en c! distant earthquakes gatherer! by the best local network of instruments in the woric! be applier! to the more basic problems of seismic wave propagation en c! the struc- ture of the Earth? A meeting of leacling seismologists was convener! in Oc- tober 1929 to assess the program, en c! Gutenberg, Affrays, Byerly, en c! MaceTwane attenclec! as external visitors. (This was the first time that the two giants of geophysics en c! seismology Affrays en c! Gutenberg hac! met.) One of the recommendations was for the establishment of a chair at Caltech. It was clear that the decision to establish the chair hac! been macle before the meeting hac! convened. As Gutenberg left Pasadena, Millikan remarkoc! significantly that he hoper! he wouic! be seeing Gutenberg soon. Gutenberg, reflecting on the arduous sea en c! lane! voyage, thought not. Unon hearing the rumor that Harvarc! was also interested in Gutenberg, Millikan acceleratec! the pro- cess. Millikan's telegram arriver! in Darmstacit two months after the meeting, "CouIc! you consider seismological post here if satisfactory arrangements conic! be macle?" Gutenberg's wire, mimicking Millikan's, react, "WouIc! con- sicler post if arrangements satisfactory." Six weeks after the 1 ~

30 BIOGRAPHICAL MEMOIRS telegram, the official letter arriver! in Darmstacit in January 1930, offering him a full professorship in geophysics and meteorology at Caltech, as well as an annointment at the Seismological Laboratory. 1 1 Linke en c! the science faculty at Frankfurt were thus procI- clec! to make a counteroffer. Frankfurt organizer! a search for a position in Germany for Gutenberg, but the hasty effort was half-heartec! en c! expectecIly unsuccessful. After some correspondence, mainly concerning salaries, in which Millikan raiser! his initial offer by 40%, Gutenberg acceptec! the position at Caltech June 4, 1930), the clean of sciences at Frankfurt congratulates! him. In September 1930, Beno, Hertha, en c! their chiTciren Arthur en c! Stephanie came to the Uniter! States to start a new life at Caltech. The begin- ning of the rapic! clevelopment of the laboratory coincides with Gutenberg's arrival in Pasadena. In 1936 responsibility for the Seismological Laboratory was transferred from the Carnegie Institution of Washing- ton to the California Institute of Technology. From 1935 onward, Gutenberg was the cle facto heat! of the Seismo- logical Laboratory because of the illness of Wood. Although Wool! hac! resister! the proposal to change the direction of the laboratory away from the phenomenology of earthquake occurrence en c! towarc! theory en c! interpretation, he states! when Gutenberg was appointee! that the effort in southern California neeclec! Gutenberg's talents en c! experience to help in the determination of epicenters en c! origin times (a misuse of Gutenberg's talents), willing "We neec! Gutenberg more than Europe cloes." Wool! persister! in his belief that the focus of the laboratory shouIc! be on local seismicity and not on global geophysics. Wood remarked in 1938 that the true cost of his illness could be measured by the relent- less effort of the Seismological Laboratory on distant earth- quakes.

BENO GUTENBERG <a ~. . 131 Even in Gutenberg's first year at Pasadena, it was clear that the work of the laboratory was undergoing a revitaliza- tion that reflected! his presence. At the annual meeting of the Seismological Society of America in 1931, six of the fourteen papers on seismolOO~'Y came from Caltech, en c! three of these bore Gutenberg's name. In contrast, at the meet- ng of the society in 1929, there were no contributions from the Seismological Laboratory among the five papers on seis- molo~v. Over the vears' many students en c! colleagues came _ ~ . . . ~ ~ . ~ ~ . ~ ~ · ~ ~ . ~ to ~asactena, attracted oy tne wealtn ot new 1cteas anct metn- ocis of cloing earthquake research en c! by the intellectual power of Gutenberg en c! his two colleagues Benioff en c! Richter. The global center of seismological research hac! shifter! from Darmstacit to Pasadena. to Gutenberg hac! now mover! from aseismic Hessen to the active seismic environment of southern California. Having spent his life to that time studying seismic wave propaga- tion from distant earthquakes, his new career allowed! him to stucly earthquakes at close range. He was now able to work on both local en c! global seismological problems. He conic! use the records from the Caltech network of WoocI- Anclerson torsion seismometers, later to be upgraclec! to the electromagnetic seismographs invented! by Benioff. Gutenberg quickly realizer! that the network conic! be user! for more than the location of local earthquakes. The re- cordin~s could he angling not only to the stu~v of local - - - -----of - - --- -- - - --r r -- - -- -- - - - ---a - - --- - ~ - -- --in - - - ~ .. . . . .. ~ .. ~ . . . . tartn structure in soutnern calliornla out also to struc- tural issues of a global nature, to Woocl's dismay, as re- markocI. Gutenberg attacker! the issues of microseisms in California en c! those of the structure of the Earth's crust in California. He user! the laboratory's archive of seismograms from a number of southern California earthquakes to cle- termine local Earth structure ~ ~ 943 ) . Wool! retiree! in 1947, en c! from that time Gutenberg was

32 BIOGRAPHICAL MEMOIRS the official director as well. While this appointment ciari- fiec! matters at the laboratory en c! generated coherence to its work, it hac! the unavoiciable clisacivantage of taking much of Gutenberg's research time for administration. He worker! hare! to stabilize the relationship between the Caltech acI- ministration en c! the laboratory cluring some clifficult times. On the global stage, Gutenberg and Richter wrote four monumental papers, On Seismic Waves (1934, 1935, 1936, 1939), covering the problems of travel-times for the many hotly waves in the Earth, amplitucles, surface waves, en c! creep-focus earthquakes. A bible for the observationalist, the papers represent the foundations of moclern observa- tional seismology. Although the titles reflect those in the earlier series of the Gottingen school, they are in no sense a revisiting of the oIcler, rather, they are a magnificent original contribution containing all that was known about observa- tions of the propagation of seismic waves through the Earth. The travel-time curves in the first of these papers (1934) were an exhaustive catalog of the properties of most of the iclentifiable seismic phases, including phases involving many multiple bounces off the surface of the Earth from within, multiple reflections off the core boundary, multiples within the core, en c! many mixer! phases, such as ScSSKP en c! oth- ers. The travel-time curves of the 1934 paper prececlec! the Jeffreys-Bullen curves by one year, and the two sets of curves were in excellent agreement for the important phases. The travel-time relations in the Gutenberg-Richter curves for roughly 30 phases are iclentifiec! only by letters. Of par- ticular interest is the branch labeler! "G." This was a long- period wave with strikingly large amplitudes from the Solomon IsTancis earthquake of October 3, 1931, to which Gutenberg and Richter (1954) assigned magnitude 7.9 (the periods were as long as 135 see). The large amplitudes were even more striking in view of the short-perioc! pass-bane! of

BENO GUTENBERG 133 the seismometers of the time. Gutenberg en c! Richter iclen- tifiec! the G-waves as horizontally polarizer! shear surface waves, which we now identify as very long-perioc! Love waves. For the Solomon IsTancis earthquake, two later arrivals of the G-waves, labeler! G2 en c! G3, were observer! at some stations of the worIcI. Gutenberg en c! Richter iclentifiec! G3 as the G-wave phase, which hac! traveler! one complete cir- cuit of the Earth farther than GI. The observation that surface waves can undergo many circuits of the Earth is an important preliminary to the stucly of the free oscillations of the Earth that began in the 1960s. In his work on the core, Gutenberg hac! notes! that the wave motions at sites in the shallow zone clic! not vanish. He assumer! that these waves were the consequence of cliffrac- tion by the boundary of the core. In her 1936 paper en- titlec! "P'" Lehmann shower! that the amplitucles of these waves in part of the shallow zone were too large, en c! she proposer! that they were clue to an inner core of the Earth Tying within Gutenberg's core. Gutenberg en c! Richter (1938) reanalyzec! the ciata on P' in the shallow zone and, using realistic moclels for the velocities in the core, concluclec! that the boundary of the inner core involves! a graclual transition over a distance of 300 km starting at a raclius that was 100 km less than Lehmann's value. Their P-wave veloc- ity in the inner core of Il.3 km/see was 2.7 km/see higher than Lehmann's en c! was precisely consistent with the cur- rent estimate clerivec! from analysis of the free oscillation spectrum of the Earth. The transition zone has clisappearec! from moclern moclels of the inner core/outer core bouncI- ary. In the 1914 paper, the P-wave velocity at the top of the core was 8.5 km/sec. In view of the high velocities in the inner core, this value was lowerec! in the 1938 paper to S.0 km/see, a figure that is the same as the value tociay. Jeffreys has clescribec! Gutenberg as being hesitant to ac

134 cept the liqu BIOGRAPHICAL MEMOIRS . laity of the core. Gutenberg was quite aware of the non-seismological arguments for a liquic! core from the ticles en c! from the figure of the Earth. But in Gutenberg's view, a very Tow but finite velocity for S-waves corresponcI- ing to a low rigiclity conic! still imply that the core conic! be mechanically weak, en c! there was no way to identify abso- lutely the absence of S-wave propagation through the core. The absence of observable S-wave propagation in the core conic! only place an upper bounc! on the value of the veloc- ity. In the 1914 paper setting forth the discovery of the core, Gutenberg calculates! the arrival times of S-phases through the core uncler the assumption that the Poisson's ratio for the core was 0.27, which would have given veloci- ties arounc! 4.7 km/see, but he fount! no arrivals at these times. In the 1923 paper for the elastic constants in the interior, Gutenberg's velocity-depth curves show that the S- wave velocities in the core are less than about I.2 km/sec. In later papers, the bounc! is lowerec! progressively. By 1959 (pp. 277-79), taking the tidal and figure-of-the-Earth issues into account, the velocity for the still unobserved! S-waves was "probably less, possible much less than" 0.3 km/see, the value for velocity is my interpretation of his threshold for the shear moclulus. In work clone in Germany, Gutenberg user! the variation of amplitucles to clecluce the existence of a weak Tow-veloc- ity zone for P-waves in the upper mantle at a depth of between 70 en c! 80 km (1932, vol. 4, p. 213~. He also specu- lated that the Tow-velocity zone might start at the top of the mantle. For more than twenty years, he steacifastly hell! to his position of the existence of the zone, even though there were times when he was almost alone in this view. In 1949, using southern California ciata, he lowerec! the depth to the low-velocity zone to around 100 km below the surface, the zone had a much stronger contrast to the regions above

BENO GUTENBERG 135 en c! below than in his earlier study. He iclentifiec! an acicli- tional low-velocity zone in the upper crust of southern Cali- fornia just above the Conrac! discontinuity (1934), which was confirmed! by showing that the arrivals of P-waves from explosions were earlier than those from earthquakes (1951~. Gutenberg also speculates! on the possibility that there were also Tow velocities in the Tower crust above the Mohorovicic discontinuity. In the ~ 950s his tenacious view began to be accepted, especially from the evidence given by Press en c! Ewing in 1956 en c! by later authors of dispersion of surface waves by the mantle channel. Throughout his career, Gutenberg was concerned! with the horizontal mobility of the continents. How was horizon- tal mobility driven? His early moclels (1930) for continental cirift involves! centrifugal en c! nonisostatic forces, forces clue to thermal contraction were aciclec! later. In September 1950 in Hershey, Pennsylvania, Gutenberg was a co-organizer of en c! active participant in a conference on flow in the Earth's interior, where much discussion centered! on convection (1951~. One of the conclusions of the conference was the importance of convection in the mantle of the Earth driven by gravitational instabilities of thermal origin. The propo- nents of convection Davic! Griggs, Harry Hess, en c! Felix Vening Meinesz were prominent. The opposite view was rep- resentec! by Francis Birch. Gutenberg stated, ". . . we ob- serve at the surface, phenomena that are possibly connecter! with convection currents at spots where the currents are going clown (or coming up) en c! that all such observations refer to belts surrounding the Pacific basin," en c! that the bottom of the Pacific is moving in the same direction rela- tive to the continents in California, Japan, Philippines, en c! New ZealancI. These may be prescient statements of the present view that the major part of subduction takes place

36 BIOGRAPHICAL MEMOIRS arounc! the rim of the Pacific en c! about plate motions, although plate tectonics was eighteen years in the future. Gutenberg's icleas about convection must have been en- couragec! by the 1950 conference, because convection in the mantle appears as an important component of his think- ing. In In tern at Constitution of the Earth (1951), he suggests that convection may be the most potent of all mechanisms for causing continental cirift. He also constructor! a tem- perature profile for the mantle to a depth of 600 km baser! on the assumption that convection below a depth of 80 km will lower the temperature gradient. The depth of 80 km was chosen to correspond! to the depth of his low-velocity zone, a zone that he associates! with Tow strength clue to elevates! temperature. In tociay's language, the lithosphere, that is, the uppermost 80 km of the Earth (his value for the thickness) en c! especially uncler the oceans, moves as a con- sequence of mantle convection. The temperatures below 80 km were significantly lower than present estimates. Later, in Physics of the Earth's Interior (1959), he extenclec! the tem- perature curve smoothly to the center of the Earth. In mak- ing the extension, Gutenberg relief! on estimates of the melting temperature of iron at core and inner core pres- sures that were consiclerably lower than present-clay esti- mates, and thus derived rather lower temperatures than present-day estimates. Gutenberg hac! never experiences! an actual earthquake until a few years after his arrival in Pasadena. The story often has been toic! that Einstein en c! Gutenberg were walk- ing across the Caltech campus in the late afternoon of March 9, 1933, so cleeply engrosser! in their scientific conversation that they failer! to notice the shaking of the grounc! in the disastrous Long Beach earthquake en c! were only macle aware of the earthquake by colleagues shortly thereafter. The story was confirmed by wives of both men, so it must have been

BENO GUTENBERG 137 true. Gutenberg clic! fee! many of the large aftershocks of the Long Beach earthquake. The large number of earthquakes in southern California presented a natural challenge to quantify the earthquake process. The start was the construction of a magnitude scale for local earthquakes (M~) in southern California using the uniformity of the WoocI-Anclerson seismographs in the To- cal network. Gutenberg hac! an important influence on Richter's publication in 1935 of the local magnitude scale. Shortly thereafter, Gutenberg en c! Richter (1936) constructor! the surface wave magnitude scale for distant earthquakes (Ms), en c! the surface wave magnitudes were normalizer! according to the local scale. For the first time, the magni- tucles of the largest earthquakes were iclentifiec! as having magnitudes from ~ to S.5. Gutenberg en c! Richter estab- lishec! the magnitude scale for creep earthquakes, which clo not excite surface waves (1945~. The magnitude scale for local earthquakes was mainly clue to Richter, the magni- tucte scale for distant earthquakes, with application to the largest earthquakes, was clue to both men, with Gutenberg as the prime mover. Some people have expresser! unhappi- ness that the magnitude scale has not been caller! the Gutenberg-Richter scale. Magnitudes are of importance in that they provicle a uni- fying parameter about which a variety of properties of earth- quakes can be relater! (1942~. The clevelopment of the mag- nitucle scale, Gutenberg's calculation of the energies racliatec! in seismic waves (1956), en c! Benioff's icleas about strain accumulation en c! relaxation allowed! for the opening of a new science: the stucly of the Earth's seismicity. This was first explorer! in the monumental book by Gutenberg en c! Richter, The Seismicity of the earth (1954), in which the statis- tics of local earthquakes were clescribecI. This was the first major catalog of great earthquakes woric~wicle, ciassifiec! not

38 BIOGRAPHICAL MEMOIRS only as to time en c! location but also as to magnitude. The statistics showed the famous universal, log-linear frequency magnitude relation with a slope close to I.0. The calcula- tion of energies for selectee! earthquakes hac! been clone earlier ~ ~ 929, pp. ~ 87, 296) . Gutenberg now embarked on a stucly to relate the energy releaser! in an earthquake to its magnitude. For the first time the energy flux in earthquakes conic! be calculatecI. The energy-frequency relation conic! now be shown to be a power law with exponent close to -2/3. In later years, the power law relation has been a para- cligm for the mocleling of seismicity en c! the earthquake process. . . In 1926 the National Research Council appointee! a com- mittee to prepare a report entitles! In tern at Constitution of the earth. Little appears to have been clone until 1937, when Gutenberg was appointee! to chair the committee en c! was charged with the task of reorganizing it. With characteristic vigor, the task was completec! in short order, en c! the vol- ume appeared in 1939, the printing was exhausted quickly. In view of the progress macle since 1939, a seconc! reviser! edition appeared in 1951 with major changes from and ad- clitions to the first eclition. The purpose of the volume was to give a scientific reacler outside the field! an overview of the status of the field and an identification of the unsolved problems. The volume responclec! to the original charge, but it was also a resource of great completeness where stu- clents conic! fins! copious references to aciclitional material. It thus became almost immediately a major and highly cited scientific resource for the evidence en c! interpretation of the composition, temperature, elastic properties, figure, density, gravity, origin en c! evolution, en c! the stress-strain state of the interior. The volume shows that major new re- sults en c! major new icleas hac! clevelopec! in the years since the Handbuch. Gutenberg was no mere managing editor,

BENO GUTENBERG 139 having written more than half of the volume himself. Where differences of opinion arose among the authors, no effort was macle to reach consensus, each author clevelopec! his material unrestrained. Only months before his cleath, Gutenberg's last book Physics of the Earth's Interior (1959) was publishecI. A companion volume on seismology was plannecI, but cleath intervened. The book focuses on many of the same subjects as In tern at Constitution, but this time the exposition is a personal, sys- tematic journey through crust, mantle, en c! core before at- tacking the issues of temperature, density, ticles, etc. The book is a remarkable summary of the properties of the interior of the Earth en c! an accounting of the vast number of sources for this information, many of them coming from Gutenberg's own measurements. Gutenberg shower! him- self to have been a voracious reacler of the literature. The book is a deep, thoughtful, and thorough monograph on geophysics en c! proves that Gutenberg was not merely a great seismologist. Remarkable in his swan song is his pre- scient identification of topics that shortly wouIc! elicit much interest. I mention two such areas. The first topic was his brief identification of the impor- tance of studies of the resonance spectrum of the Earth. WouIc! not Gutenberg have been exciter! by the unprec- eclentec! observations of the rich resonance spectra that re- sultec! from recordings of the great Chilean earthquake of ~ 960, which occurrec! four months after his cleath? The observations of these spectra triggerec! a grant! flowering of activity in inverse theory en c! ultra-Ion" perioc! seismology, in particular, density estimates for the Earth's interior conic! be clerivec! from the spectra without assumptions about com- pressibility or other properties. The seconc! topic was Gutenberg's commitment to the icleas of convection en c! continental drift, although he clic!

40 BIOGRAPHICAL MEMOIRS not connect the two. That linkage was not to happen for another nine years, with the clevelopment of the plate tec- tonics moclel. However, he macle a definite insightful asser- tion that convection wouic! be shown to be responsible for mountain builcling en c! earthquakes, struction of the continental geometry into an almost single mass in Cretaceous times, that climates on the Tong-time scale will clepenc! on unclerstancling continental cirift. After the assumption of power by the Nazis, Gutenberg kept his contacts in Germany alive. During these prewar years, he helpec! many Jewish scientists escape from Ger- many. Notable among these were Viktor Conrad, editor of Geriands Beitrage, en c! Helmut Lancisberg. Lancisberg hac! been Gutenberg's student en c! was his successor as director of the earthquake service at the Taunus observatory. In 1934 Lancisberg fleck to the Uniter! States with Gutenberg's help and became professor at Pennsylvania State College in College Park. Gutenberg returnee! to the problem of microseisms en c! their meteorological causes while working on a project for the U.S. Navy cluring en c! after WorIc! War II. Gutenberg was a valuable World War II consultant to the Navy, apply- ing his knowlecige of the structure of the upper atmosphere to the problems of ballistics. He also worker! on applica- tions of the observations of microseisms to locate hurri- canes in the Caribbean en c! the western Pacific. Within a few weeks of the war's end, Gutenberg wrote to the Navy stating that for many years he had been suggesting the use of microseisms for forecasting of storms, especially hurri- canes. No longer were microseisms associates! with surf, he asserted, but now they were associates! with clifferential ToacI- ing of the ocean bottom by distant storms. The theory was given by M. Longuet-Higgins in 1950. The results that he hac! obtainer! in the Caribbean area exceeclec! by far his and from his recon

BENO GUTENBERG 141 most optimistic hopes. In the spring of 1947 the Navy sent Gutenberg to Japan, Guam, and the Philippines to do addi- tional research on microseisms, as well as to consult on the problems of the revival of seismological research in these countries in the wake of the war. Gutenberg was small of stature, very personable, en c! lively. He was well organizer! en c! kept to a precise tinily schecluTe. Although his scientific clemancis on himself were rigorous, Gutenberg was gentle en c! self-effacing in his relationship with others. He was helpful to anyone who asker! a question of him en c! was tolerant of critics. Gutenberg was a man who conic! give his colleagues en c! students a liberal ecluca- tion in scientific method, macle pleasantly easy by kinciness, patience, amazing industry, en c! a clelightful sense of hu- mor. He was a cultures! incliviclual, well react, en c! with wicle interests reflections of his broac! European education. Having inheritec! his mother's musical talents, Beno learner! to play the piano, a skill that was to last him through his entire life. In his earliest years in Darmstacit, Beno sang in the synagogue choir en c! often playoc! the organ. In the Pasadena years, Einstein playoc! the violin in chamber mu- sic events organizer! at the Gutenberg home. At the enc! of WorIc! War II, in a reprise of the bartering activity of earlier years, Gutenberg collectec! the accumulates! royalties on his publications in Germany by payment in the form of numer- ous piano scores for two en c! four hands. His bookplate shows the Owl of Wisdom with a seismo- gram in its beak in flight arounc! the Gottingen Institute of Geophysics. The text on the bookplate repeats the motto of the Lehrbuch: Viele Zeichen gibt uns clie Natur, Leitet uns auf cler Erkenntnis Spur, Weist uns ihre wunclerbaren Bahnen, Lasst clie Seele uns cles WeTtalis ahnen!

42 BIOGRAPHICAL MEMOIRS Frank Press, former president of the National Academy of Sciences, has stated, "Gutenberg was absolutely cleclicatec! to seismology, especially to observational data and their in- terpretation. His work carries the mark of much self-confi- clence in his ability to examine ciata not as a statistician but as a skillful interpreter en c! synthesizer." Throughout his entire career, Gutenberg's reputation rester! on the solic! foundation of his own reacting with great accuracy en c! in- sight of the arrival times en c! other properties of seismic waves on the seismic records. In contrast to the moclus op- erancli of many moclern scientists, Press continues, "Gutenberg conic! ciraw conclusions from sparse en c! noisy ciata with uncanny insight that" structures such as a core en c! a low-velocity zone en c! continent-ocean differences couIc! be states! to exist. Gutenberg's belief in the power of the ciata to resolve issues of differences in moclels is given by the penultimate sentence of Physics of the Earth's Interior: THE DATA "MUST BE GREATLY AMPLIFIED AND STRENGTHENED" (Gutenberg's capitalization and punc- tuation). Gutenberg dominated the field of observational seismology as no one before or after. At the time of his cleath, Byerly remarkocI, "It is rare that anyone writes a pa- per in seismology without referring to him." When one reads the list of Beno Gutenberg's contribu- tions to the full range of seismological studies spanning seismicity, wave propagation in the Earth, en c! the physics of the Earth's interior one must be in awe of his insights, his breadth, his thoroughness, his vigor, en c! especially his creativity. AM MOST GRATEFUL to Caltech for allowing me access to a variety of documents in its archival files of Beno Gutenberg and Charles F. Richter and to a transcript of an oral history interview with Hertha Gutenberg. The history of the Seismological Laboratory as given in

BENO GUTENBERG 143 Milikan's School by Tudith R. Goodstein (W. W. Norton, New York, 1991) was valuable. I have also found the following biographical articles helpful: P. Byerly. Trans. Am. Geophys. Union 34~1954~:353-54. C. F. Richter. Proc. Geol. Soc. Am., Annual Report for 1960, (1962) :93 104. H.Jeffreys. Q.J. Astron. Soc. 1(1960):239-42. T. Schweitzer. Mitteil. Deutsch. Geophys. Gesell. 3~1989~:8-10. D. L. Anderson. In Encyclopedia of Earth Sciences, vol. 1, pp. 444-45. Macmillan: New York, 1996. If it should be perceived that I have appropriated some of the language in the above documents, the accusation is well founded. These authors have been a most valuable resource, not only for their thoughts on the life and science of Beno Gutenberg but also in their admirable choice of words. HONORS 1945 Member, National Academy of Sciences Honorary member, Royal Society of New Zealand 1945-47 President, Seismological Society of America 1947 Foreign member, Academia dei Lincei Honorary member, Finnish Geographical Society 1948 Foreign member, Finnish Academy of Letters and Sciences 1949 Foreign member, Royal Swedish Academy of Sciences Member, Washington Academy of Sciences 1950 Fellow, American Academy of Arts and Sciences 1951-54 President, International Association of Seismology and the Physics of the Earth's Interior 1952 1953 1954 1955 1956 Prix Lagrange, Royal Belgian Academy of Sciences Bowie Medal, American Geophysical Union Foreign Member, Geological Society (London) Honorary doctorate, University of Uppsala Emil-Wiechert Medal, German Geophysical Society

44 BIOGRAPHICAL MEMOIRS SELECTED BIBLIOGRAPHY 1912 .. With K. Zoppritz and L. Geiger. Uber Erdbenwellen V. Konstitution des Erdinnern, erschlossen aus dem Bodenverruckungsverhaltnis der einmal reflektierten zu den direkten Longitudinalwellen, und einige andere Beobachtungen uber Erdbenwellen. Nachr. d. Kon. Ges. d. Wiss. Gottingen, math.phys. Kl. 121-206. With L. Geiger. Uber Erdbobenwellen VI. Konstitution des Erdinnern, erschlossen aus der Intensitat longitudinaler und transversaler Erdbenwellen, und einige Beobachtungen an den Vorlaufern. Nachr. d. Kon. Ges. d. Wiss. Gottingen, math. phys. Kl. 623-75. Die seismische Bodenunruhe (dissertation). Gerl. Beitrage z. Geophys. 11 :314-53. 1914 .. Uber Erdbenwellen VIIA. Beobachtungen an Registrierungen von Fernboben in Gottingen und Folgerungen uber die Konstitution des Erdkorpers. Nachr. d. Kon. Ges. d. Wiss. Gottingen, math.phys. Kl. 125-76. 1923 Die elastischen Konstanten im Erdinnern. Phys. Zs. 24:296-99. 1924 Dispersion und Extinktion von seismischen Oberflachenwellen und der Aufbau der obersten Erdschichten. Phys. Zs. 25:377-81. 1925 DerAufbau derErde. Berlin: Gebr. Borntrager. 1926 Die Geschwindigkeit des Schalles in der Atmosphare. Phys. Zs. 27:84- 86. 1927 Die Veranderungen der Erdkruste durch Fliessbewegungen. Gerl. Beitrage z. Geophys. 16:239-47; 18:281-91.

BENO GUTENBERG 1929 145 Die physikalische Vorgange bei Erdboben. In Lehrbuch der Geophysik, ea., pp. 220-307. Berlin: Gebr. Borntrager. Der Physikalische Aufbau des Erdkorpers. In Lehrbuch der Geophysik, ea., pp. 536-81. Berlin: Gebr. Borntrager. 1930 Schallgeschwindigkeit und Temperatur in der Stratosphare. Gerl. Beiotrage z. Geophys. 27:217-25. Hypotheses on the development of the Earth. 7. Wash. A cad. Sci. 20:17-25. 1932 Theorie der Erdbobenwellen. In Handbuch der Geophysik, vol. 4, ea., pp. 1-150. Berlin: Gebr. Borntrager. Beobachtungen von Erdbobenwellen. In Handbuch der Geophysik, vol. 4, ea., pp. 151-263. Berlin: Gebr. Borntrager. Der Aufbau der Atmosphare. In Handbuch der Geophysik, vol. 9, ea., pp. 1-88. Berlin: Gebr. Borntrager. Die Schallausbreitung in der Atmosphare. In Handbuch der Geophysik, vol. 9, ea., pp. 89-145. Berlin: Gebr. Borntrager. 1933 Abkuhlung und Temperatur der Erde. In Handbuch der Geophysik, vol. 2, ea., pp. 1-35. Berlin: Gebr. Borntrager. Der Physikalische Aufbau der Erde. In Handbuch der Geophysik, vol. 2, ea., pp. 440-564. Berlin: Gebr. Borntrager. 1934 The propagation of the longitudinal waves produced by the Long Beach earthquake. Gerl. Beitrage z. Geophys. 41:114-20. With C. F. Richter. On seismic waves. I. Gerl. Beitrage z. Geophys. 43:56-133. 1935 With C. F. Richter. On seismic waves. II. Gerl. Beitrage z. Geophys. 45:280-360.

146 BIOGRAPHICAL MEMOIRS 1936 With C. F. Richter. On seismic waves. III. Gerl. Beitrage z. Geophys. 47:73-131. The structure of the Earth's crust and the spreading of the conti- nents. Bull. Geol. Soc. Am. 47:1587-1610. 1938 With C. F. Richter. P and the Earth's core. Mon. Not. Roy. Astron. Soc. Geophys. Suppl. 4:363-72. 1939 With C. F. Richter. On seismic waves. IV. Gerl. Beitrage z. Geophys. 54:94-136. 1940 Krafte in der Erdkruste. In Handbuch der Geophysik, vol. 3, ea., pp. 1- 31. Berlin: Gebr. Borntrager. Geotektonische Hypothesen. In Handbuch der Geophysik, vol. 3, ea., pp. 442-544. Berlin: Gebr. Borntrager. 1942 With C. F. Richter. Earthquake magnitude, intensity, energy and acceleration. Bull. Seismol. Soc. Am. 32: 163-91. 1943 Seismological evidence for roots of mountains. Bull. Geol. Soc. Am. 54:473-98. 1945 Magnitude determination for deep-focus earthquakes. Bull. Seismol. Soc. Am. 35:117-30. 1948 On the layer of relatively low wave velocity at a depth of about 80 kilometers. Bull. Seismol. Soc. Am. 38:121-48. 1951 The cooling of the Earth and the temperature in its interior. In Internal Constitution of the earth, ea., pp. 150-66. New York: Dover.

BENO GUTENBERG 147 Forces in the Earth. In Internal Constitution of the earth, ea., pp. 167- 77. New York: Dover. Hypotheses on the development of the Earth. In Internal Constitu- tion of the Earth, ea., pp. 178-226. New York: Dover. With C. F. Richter. Evidence from deep focus earthquakes. In Inter- nal Constitution of the Earth, ea., pp. 305-313. New York: Dover. With C. F. Richter. Structure of the crust. In Internal Constitution of the Earth, ea., pp. 314-39. New York: Dover. The elastic constants in the interior of the Earth. In Internal Consti- tution of the Earth, ea., pp. 364-81. New York: Dover. With H. Benioff. Strain characteristics of the Earth's interior. In Internal Constitution of the Earth, ea., pp. 382-407. New York: Do ver. With H. Benioff, T. M. Burgers, and D. Griggs. Colloquium on plas- tic flow and deformation within the Earth. Trans. Am. Geophys. Union 32:497-543. Travel times from blasts in southern California. Bull. Seismol. Soc. Am. 41:5-12. 1953 Wave velocities at depths between 50 and 600 kilometers. Bull. Seismol. Soc. Am. 43:223-32. 1954 With C. F. Richter. Seismicity of the Earth and Associated Phenomena. Princeton, N.T.: Princeton University Press. 1956 The energy of earthquakes. Q. 7. Geol. Soc. Lond. 112:1 -14. 1958 Velocity of seismic waves in the Earth's mantle. Trans. Am. Geophys. Union 39:486-89. 1959 Physics of the Earth's Interior. New York: Academic Press.

Next: Mary R. Haas »
Biographical Memoirs: V.76 Get This Book
×
Buy Hardback | $107.00
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

Biographic Memoirs Volume 76 contains the biographies of deceased members of the National Academy of Sciences and bibliographies of their published works. Each biographical essay was written by a member of the Academy familiar with the professional career of the deceased. For historical and bibliographical purposes, these volumes are worth returning to time and again.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  6. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!