The March 5, 1987, Ecuador Earthquakes Mass Wasting and Socioeconomic Effects (1991) / Chapter Skim
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6 Effects of Lifelines
6 Effects of Lifelines
Pages 83-99
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From page 83... ...
Cornell University, Ithaca, New York GENERAL OBSERVATIONS From March 19 to April 3, 1987, reconnaissance personnel were sent from Cornell University to Ecuador to evaluate the effects on lifelines of the March 5, 1987, earthquakes. An additional visit was made on August 17-27 to collect data concerning the effects of landslides and flooding on key lifeline facilities and to observe reconstruction efforts in areas most severely influenced by the earthquakes.
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From page 84... ...
The full extent of pipeline damage in Baeza could not be determined; however, there was considerable damage to one- and two-story structures, primarily of reinforced masonry construction. Electric Power Systems Officials with EEQ, the municipal electricity authority for Quito, were contacted.
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From page 85... ...
Landslides in volcaniclastic deposits were caused by the earthquakes and interrupted traffic between the cities of Quito and Cayambe (Figure 1.1~. The majority of these landslides originated in the faces of steep readouts and involved relatively shallow raveling and toppling of cemented sands, ash, and weak rock.
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From page 86... ...
The pipeline is the main crude oil transportation facility in the country, conveying virtually all oil from the eastern oil fields to a marine terminal port near Esmeraldas on the Pacific Ocean (Figure 6.1~. The pipeline operates at a maximum internal pressure of 9.7 MPa and moves from 250,000 to 300,000 barrels of oil a day.
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From page 87... ...
The area of most severe disruption is shown by means of the hachured zone in Figure 6.1. It was in this general region that landslides and floods triggered by the earthquake damaged the line pipe and the Salado pump station (location 3~.
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From page 88... ...
Between the Aguanco and Salado Rivers, the pipeline attains a maximum elevation of 1,700 m, after which it descends approximately 500 m to the Coca River floodplain and then follows the N bank of the river to the Salado pump station. The Coca River is deeply entrenched and borders the southeastern foothills of the active volcano, Reventador.
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From page 89... ...
of greatest pipeline damage. Approximately 12 km of the pipeline was destroyed along the banks of the Coca River, from just E of the Salado pump station to a location roughly 12 km E of the confluence of the Salado and Coca rivers.
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From page 90... ...
Many landslides and debris flows in this section originated in the younger volcaniclastic deposits surrounding Reventador Volcano at elevations between 1,400 and 2,000 m. The pipeline was severed by landslides and debris flows at two other locations approximately 7 and 10 km E of the area depicted in Figure 6.3.
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From page 91... ...
EFFECTS ON LIFELINES 91 FIGURE 6.6 Pipeline broken by a debris flow that has eroded 6 m below the pipeline right of way. _ I—~ i ~ ~ ~ ~ 1 1 _ 111 FIGURE 6.7 Flooding along tile Coca River.
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From page 92... ...
FIGURE 6.9 Broad fan of a very large debris flow with the Trans-Ecuadorian pipeline deformed in the direction of debris movement.
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From page 93... ...
The location of the landslide and the outline of the debris flow are shown in the inset diagram in Figure 6.10. As shown in Figure 6.10, the Salado pump station is composed of several structures, the most important of which include the main gate valve, control building, generators, pump house, water tank, crude oil tank, communication equipment, and personnel housing.
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From page 94... ...
In addition, one of the elevated diesel fuel tanks for the generators overturned as a result of the earthquakes. Pump House The pump house contained five diesel engine pumps, each supported on isolated concrete blocks and underlying 300-mm-diameter steel pipe piles.
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From page 95... ...
A large circumferential bulge, or "elephant's foot" buckle, developed at the juncture between the tank and its concrete ring wall (Figure 6.13~. The main pipe outlet from the tank pulled free of a compression coupling, thereby disconnecting the tank from the station piping network.
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From page 96... ...
96 THE MARCH 5, 1987, ECUADOR EARTHQUAKES FIGURE 6.12 Damaged water-storage tank at the Salado pump station. FIGURE 6.13 Circumferential buckling and pipe pullout of the water tank at the Salado pump station.
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From page 97... ...
is the main transportation artery from Quito to the eastern oil field. Flooding destroyed the highway bridges at the Salado and Aguarico rivers as well as
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From page 98... ...
Seismic shaking had only a limited effect on the line pipe, whereas permanent ground deformations had a severe and extensive influence. Landslides and debris flows caused most of the pipeline damage and contributed to virtually all ruptures and permanent deformations of the line.
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From page 99... ...
Mr. Gustavo Freile of Harbert Engineers provided critical assistance during both reconnaissance visits.
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