DUMP MAY BE PRONE TO QUAKE DAMAGE.

Byline: Robert Monroe Staff Writer

New seismic data show areas north of Granada Hills - including the Sunshine Canyon Landfill - are especially prone to earthquake damage, but the dump's operators insist their dump is safe.

Opponents of the Sunshine Canyon facility said they will try to use the new study - which used data from detonating explosive devices at strategic points across a broad area - to keep the dump from reopening.

``It's one more thing to bring up and one reason not to put the landfill so close to the water,'' said North Valley Coalition President Wayde Hunter, whose group is seeking a court order to force the city and BFI to redo its environmental impact report.

Browning Ferris Industries, which operates the dump, hopes to reopen the landfill by the middle of 2001.

``The landfill has withstood direct hits on two occasions, the Northridge Quake and in 1971,'' said BFI spokesman Arnie Berghoff, adding that the landfill was built to survive the strongest earthquake expected to hit Los Angeles.

Researchers said the Northridge Earthquake in 1994, which the dump survived, produced the same kind of shaking that they are studying in their tests.

``Go look at what happened during 1994 and that's a good indication of what will happen in the future,'' said Gary Fuis, a U.S. Geological Survey geophysicist and co-leader of the project.

BFI environmental consultant James Aidukas said he was not familiar with the early results of the Valley study but said they do not change the assessment of the risk the dump would breach in a quake.

``We would consider it no more than data that we would put in the files,'' he said.

Preliminary results from the Los Angeles Region Seismic Survey show that an area stretching from Reseda to Lake Castaic sits atop a basin of loose sedimentary rock that is more prone to violent shaking during a temblor, a lead researcher said.

``It's a deep trough filled with mud and sand and gravel run down from the mountains,'' Fuis said. ``It traps earthquake energy and holds on to it.''

In October, scientists detonated buried explosives placed in a line running from the ocean to the High Desert through the Valley, including near the landfill. By measuring the underground sound waves, scientists sought to identify where new faults might run and measure existing ones.

Researchers plan to chart the dimensions of the sedimentary basin under Sunshine Canyon.

Fuis said the exact depth of the sedimentary basin and its shape have to be understood to get a clear picture of how much the basin shakes during earthquakes. A subterranean map might not be completed for years, he said.

Hunter said he and activists are concerned that a quake could breach the landfill, causing runoff to contaminate the water supply.

Hunter cast doubt on their claims of the facility's imperviousness.

``BFI would have you believe that it's a stainless steel bowl and that nothing could leak out into the Valley, and I'm saying: Wrong.''

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