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Proof Against Belmont Is Shaky

May 11, 2003|Jay Namson and Thom Davis | Jay Namson and Thom Davis are geologists who specialize in oil and gas exploration and earthquake hazard analysis.

Unless something changes soon, the Los Angeles Unified School District's uncompleted Belmont Learning Complex will be needlessly torn down or modified, squandering nearly $200 million of taxpayer funds, subjecting students to years more of severely overcrowded classrooms or painfully long bus rides and establishing an unscientific precedent for the evaluation of seismic safety in the region. The latest controversy stems from the discovery of a fault under a portion of the Belmont site late last year. The real question is whether students can safely occupy the school.

As geologists who have studied this region for 20 years, viewed the Belmont fault and read the reports from the LAUSD's geologic consultants, we believe the site is safe -- safe enough that we would send our own kids to Belmont.

State law rightly bans the building of a school on an active fault -- one that has moved in the last 11,000 years. The LAUSD and its geologists have not been able to determine that the fault is active but, citing abundant caution, have chosen to assume it is. Caution is good. However, jumping to conclusions without all the available evidence is another matter, and that's the case with Belmont.

The fault beneath Belmont is observed only in the bedrock (called the Puente/Monterey Formation), deposited on an unstable sea floor 6 million to 8 million years ago. Students on their first geology field trip learn that bedrock faults are extremely common in California, but only an infinitesimally small number of these faults are active or move in response to earthquakes.

The discovery of a fault at Belmont is not surprising given the age and type of bedrock at the site. Finding an active fault that would make the site unsafe is extremely unlikely. So we were not surprised to find ample evidence that this fault had probably not moved for at least 4 million years.

When we viewed the trenches at the site we saw minor faults and soft sediment deformation structures consistent with fault movement 6 million to 8 million years ago. A few blocks south of the site there is a 5-million to 6-million-year-old bed unbroken by the fault. There are no signs that the seal over the adjacent oil field had been broken by an active fault. And the fault dies out on the north portion of the site too. These are all strong indications of a fault that is inactive and stable, much like the millions of bedrock faults that exist throughout California.

The problem is that the LAUSD and its geologic consultants did not examine all the evidence. They asked only one of the many questions to determine whether the fault remained active: Is the surface soil broken by the fault? However, because of prior site development, there was no undisturbed surface soil to examine.

Unfortunately, their study stopped there, ignoring the ample evidence of older deformation in the bedrock and other evidence inconsistent with an active fault. Even worse, the LAUSD prematurely pronounced the site unsafe in repeated public comments. Now we fear that LAUSD officials will be unable to restore public confidence in the site's safety after they have created widespread, though unsupported, public fear that the site is not safe.

We believe this is irresponsible. The LAUSD is poised to abandon a nearly finished school based on a half-finished study; the board is scheduled to vote on it this week. The cost of a comprehensive study of the fault, employing a wide range of geologic expertise, is minuscule compared with the hundreds of millions of dollars the school district is prepared to squander by abandoning the project.

A complete study would help the LAUSD make the right decision for the future of Belmont. A full study would avoid the precedent now being created, one based more on fault hobgoblins than geologic understanding. What a tragedy it would be if a flawed study thwarted much-needed school development.

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