Active Tectonics Impact on Society (1986) / Chapter Skim
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15. Volcanoes: Tectonic Setting and Impact on Society
15. Volcanoes: Tectonic Setting and Impact on Society
Pages 231-246
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From page 231... ...
But in so doing, volcanologists stray into unfamiliar territory, dealing frequently with public officials, land managers, and members of the news media. Misunderstandings may arise among these groups because of differences in background, objectives, and perceptions, and at times even well-based scientific opinions may encounter skepticism.
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From page 232... ...
Nevertheless, all but a few of the world's active volcanoes lie close enough to the major zones of active earth movement to have long provoked speculation and discussion on the nature of and connection between earthquakes and volcanoes. The current theory of plate tectonics provides a unifying framework explaining the association.
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From page 233... ...
The prehistoric but potentially active volcanic centers throughout this region are associated with an extremely complicated and continually changing state of stress, and pulses of motion along structural lineaments have been proposed as triggering the formation of magma (Smith and Luedke, 1984~. These ideas demonstrate the important role of volcanism in the past and ongoing development of the concepts of plate tectonics.
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From page 234... ...
Pyroclastic falls probably constitute the most common of all volcanic hazards. A small to moderate amount of tephra, with thicknesses of up to a few centimeters, is a nuisance and causes damage and inconvenience by clogging machinery and covering buildings, roads, and vegetation.
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From page 235... ...
At Mount St. Helens, the debris avalanche launched a whole array of additional volcanic processes, including pyroclastic surges, flows and falls, and lahars.
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From page 236... ...
Among the largest powers, only Japan has active volcanoes in areas where they have direct and frequent influence on a high proportion of the population near the centers of national life. This selective distribution of volcanoes relative to centers of major influence in world affairs appears to be a cause of the rather low level of concern and under standing of volcanic hazards among the people of the world.
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From page 237... ...
Volcano observatories have been established at a several frequently active volcanoes throughout the world, where systematic sur
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From page 238... ...
Even so, on the average about a dozen volcanoes per year cause appreciable damage and sometimes human casualties, and from one to a few times per decade volcanic eruptions cause major damage and disruption with many casualties. In spite of the subordinate ranking of volcanic hazards in public consciousness, most countries with active DONALD W
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From page 239... ...
At most volcanoes the numbers of earthquakes per unit time and the rate of seismic energy release show systematic increases prior to eruptions. Such increases, particularly when accompanied by or interspersed with volcanic tremor, are one of the most important techniques in forecasting volcanic eruptions (Figure 15.2~.
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From page 240... ...
Modern collecting and analytical techniques can yield reliable results for gas composition, and changes in ratios among different gases can help scientists to infer the eruptive potential of a volcano. Changes in the absolute emission rates of volcanic gas empirically would seem to reflect the likelihood of eruption because, as magma rises, confining pressure decreases and cracks develop in adjacent rocks, which should tend to increase gas flux.
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From page 241... ...
When the volcano becomes active, all become responsible for critical functions. In many branches of science, scientists have but minimal or casual dealings with public officials, land managers, and news media, but when working with an active volcano, scientists must deal regularly with them all.
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From page 242... ...
Property and land managers can anticipate questions regarding operations and access on their property and develop contingency policies in conjunction with public officials. Drills may be held by all groups for practice and to test and improve the plans.
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From page 243... ...
Both public officials and large land managers deal with the press regularly, so channels and procedures are normally already in place. Volcanologists, however, may be unfamiliar with media procedures, so it is important that they prepare themselves.
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From page 244... ...
Summary of the Volcanolog~st's Role in Enhancing Public Understanding People properly informed about the character and behavior patterns of volcanoes are best prepared to deal with volcano emergencies when they arise. Only near volcanoes that either erupt frequently or have just recently erupted, however, are members of the general public likely to have much awareness of volcano hazards (Murton and ShimaburuPo, 1974~.
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From page 245... ...
It is important for scientists to be tactful, patient, and perservering as they deal with the news media and public officials on matters concerning volcano hazards. They must find ways to employ the same qualities of innovation and resourcefulness that they normally display in scientific research if their hazard messages to the public are to be heard and heeded.
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From page 246... ...
Volcanic hazards on the island of Hawaii, U.S.
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