ML19260C070
| ML19260C070 | |
| Person / Time | |
|---|---|
| Issue date: | 11/02/1979 |
| From: | Heller L Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19260C066 | List: |
| References | |
| NUDOCS 7912180316 | |
| Download: ML19260C070 (5) | |
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OBSERVED EFFECTS OF THE 10/15/79 EL CENTRO EARTHQUAKE SY:
L. W. HELLER Precarations On October 17, 1979, I contacted L. Lauro of the Corps of Engineers, Los Angeles District to learn of any Corps activities related to the El Centro earthquake. He said the Corps had dispatached a man to inspect a Corps dam about 150 miles from El Centro although the dam operators reported that no damage to their dam had occurred. Mr. Lauro told me that a good picture of earthquake effects could be obtained from Robert Douglas of the Federal Disaster Assistance (FDA) office in Los Angeles. My call to Mr. Douglas revealed that the FDA had a local connand center at the Imperial County airport which maintained a map of damage locations within the county for FDA claim purposes. Dave Pearson, County Engineer, was in charge of this local office. A call to Mr. Pearson indicated that they had records of bridge ar.d structural da age and that records of damage to pipelines and canal banks could be obtained from Mr. Donald A.
Twogood at the Imperial Irrigation District office in Imperial, California.
Observations Dr. Reiter and I, accompanied by Howard Levin SEP, arrived in El Centro, California at about 6:30 a.m. on October 18, 1979. We contacted Bob Page of the USGS and obtained the latest USGS information on earthquake effects.
We plotted their fault break, liquefaction, and ground rupture locations on our map of Imperial County. We also pinpointed locations of lateral spreading and reported liquefaction. We then stopped at the site of the damaged six-story tall County Building and tock a few photographs, then proceecec to the FDA office at the County airport. There we obtained locations 16N303
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2-of damaged bridges, roads, and learned of damage to a Union oil tank farm.
While at the FDA office, we felt a strong aftershock.
Leon and I at.ked the Union oil tank farm superintendent to show us the damage sustained by his facility. He was hesitant, but honored our request. One tank was bucklad at the bottom and one leaked from a smail split of a weld seam at the bottom of the tank. We took photos of these effects.
A few tanks had suffered breaks in small pipes between the tank outlet and the point of burial in the ground. Most tanks evidenced a small crack between the soil and concrete mat foundation perhaps due to some bearing movement on the order of 1/8 inch. Some tank restraints were bent.
We drove to the Imperial fault break on Harris Road and took some pictures of the fault offset. We noticed a domestic water pump and pressure tank system had been repaired due to apparent pull-out of a joint of the plastic pipe where the shallow buried pipe crossed the Icperial fault break.
I talked to a landowner farmer who was passing by. He said his cotton picker had been tipped over by the quake and the walls of his 4 year old California stucco house were heavily cracked. We drove to a number of points along the Imperial fault break. At 1:00 p.m., we joined Joe Matore and Howard Levin at the Imperial Irrigation District Steam-Electric plant.
I' observed minor concrete spalling and distortion of some equipment seismic restraints.
We left Joe and Howard at the plant and drive toward the All American canal area. We went to Heber Road, where bridge damage had been indicated by USGS and FDA. We found a 15 yard wide by 40 yard long subsidence or land spreading area. We also discovered sand boils in a field some 20-30 yards from the edge cf the subsidence cr sprea:ing area. The land screading locally closed and distorted an irrigation channel parallel to the road.
We proceeded to the Alamo River bricge (about 1/- m.lef,,where movemer.t of the west pier downslope was noted. Ground cracking and slope movement was 16D7 304
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. coc=cn adjacent to the west bridge pier at the Alamo river on Heber road.
We continued southward to the all American Canal south of Route 98. At Rood Road, canal bank repairs were being completeo. We hunted for canal damage areas and for the location of Mesa lateral #3. At Mesa lateral
- 3, we noted general slope failures along the North Bank of the All American Canal. Apparently some spreading had also occurred, as tiny
' Islands had appeared above the water level in the canal. Caterpillars, graders, and water wagons were completing repairs to the slide areas, but the channel had not yet been dredged. We understood that, shortly after the earthquake, water flow ceased in some parts of this canal. After inspecting the canal, we headed wast toward the reported large area of liquefaction at the Highline Canal junction with the American Canal. This appeared to be too great a distance to travel and still see fault breaks across Inter-state 8 before dark, so we reversed our route. We found the breaks in I-8, which dispiaced two sawed concrete pavement slabs (each slab was about 20 ft long). At the I-8 break, the fault trace could be seen in the fields. A concrete' lined irrigation ditch ran parallel to I-8.
One 10 ft long section of the canal liner was lifted and moved about 6-8 inches, but adjoining sections appeared undisturbed. As dusk approached, we returned to the USGS information point (Rm 21 of the American Motel in El Centro, manned by Dr. David Boore and others of the USGS) to obtain an update of their activities, aftershocks locations, etc.
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On Friday morning we dreve to Brawlcy to sea the bridge delaae at New River on Route 86 and the reported slides along the bank of the New River, north of the bridge. Two bridges carry four lanes of traffic on route 86.
The southernmost bridge suffered considerable damage at its western abutment. The northern span was being repaired for temporary service, probably at reduced load limits. The main source of difficulty appeared to be the movement of the pile cap abutments toward the tenterline of the river due to downslope movement of the bank and fill materials surrounding the piles. At the west pier of the southern span, movement was aggrevated by erosion of fill and backfill from beneath the pile cap and the apparent pre-earthquake tilting of thepile bent (Wooden shims had been driven between the top of thepier and the bearing block of this span).
Slides along the bank of New River northwest of Brawley did not affect the flow of the river, but will require bank maintenance. These slides caused ground cracking and subsidence of the bank scme distance from the river, indicative of liquefactiori effects. Total movement of the slide blocks were probably between one and two feet.
Recommendations In my view, the trip to observe effects was a productive experience, but a couple of recommendations for future trips of this sort seem evident.
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5-(1)Personnelshouldarriheonsi_teassoonaspossible. A large part t
of the repairs to canal banks had'been completed just 3 days'after the damage occurred, which precluded an assessment of the mechanism.of these failures.
(2) Personnel should plan on spending at least two to three full days, in the damage area. We were not able to utilize all.of the contacts we hadestablishedpricrtoarrihingonsite. Wereceihe'drequeststomeet with other groups which we could not honor due to time restraints.
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