Comments on: Two dams

By: Andrew

Andrew — Tue, 23 Oct 2012 02:53:24 +0000

Yes, a new strand of the Hayward fault was recently mapped in the area south of the Chabot dam. Here's the graphic from the Tribune; don't expect the link to last more than a few months. It's not really significant; it runs through uninhabited land and, being short, can't store much seismic energy. The dam is very secure against earthquakes, as far as I can tell, because of its old-fashioned massive construction consisting of packed clay. If it did fail, that would be pretty awful. Unfortunately, I can't figure out where the California Geological Survey is hiding this new information.

By: Anna

Anna — Mon, 22 Oct 2012 20:44:24 +0000

They just found a new fault right near Lake Chabot – and if there is a dam failure there – EBMUD has documented that there will be catastrophic damage to San Leandra and Southern Oakland areas.

By: Andrew

Andrew — Sat, 27 Feb 2010 22:27:00 +0000

James, there are faults and faults. Any fracture that offsets rocks qualifies as a fault, but there are no active major or minor tectonic faults, besides the Hayward fault, near Lake Chabot Dam. The ridge that buttresses the dam is a different rock type (the volcanic rock of Leona Quarry) from what surrounds it.

By: Erik

Erik — Sat, 27 Feb 2010 17:38:28 +0000

It’s actually extremely common for dams to be build over faults. The best place for a dam is a narrow, deep valley through which a bigger valley/depression drains, and a fault is the most likely thing to allow a narrow, deep exiting valley in that situation to form.

There may be a small fault under Chabot Dam but it probably isn’t considered active. I.e. there are no signs of a fault there having moved in the last 10,000 years.

By: james

james — Sat, 27 Feb 2010 17:01:12 +0000

lake chabot dam i believe has a fault directly under it look for yourself I spent 3 years hiking the trail along the north side of the lake lots of evidence of a smaller fault

By: SteveN

SteveN — Tue, 02 Jun 2009 18:25:12 +0000

it’s good to bring this to people’s attention. in teaching geology classes, i have only once, in 11 years, had a student who knew that Fremont stands to be annihilated by an earthquake-induced dam ruptures. most people simply have no idea about this, and are horrified when i show them the ABAG dam failure maps. :)

By: rob

rob — Tue, 02 Jun 2009 06:09:51 +0000

its on the north side. if you go into the parking lot that’s off the frontage road of hwy 24 and then walk up the grassy slope, you’re walking onto the dam.

By: peter

peter — Tue, 02 Jun 2009 06:07:58 +0000

Where exactly is the dam at Temescal? I go there a lot and would love to check out Mr. Chabot’s handiwork. Thanks for the link on the construction of the dams, as well! I really look forward to posts on this blog.

By: rob

rob — Mon, 01 Jun 2009 21:14:38 +0000

yes as i recall i heard a very crazy story on NPR about these people doing glacier research and lakes disappearing overnight.

By: Andrew

Andrew — Mon, 01 Jun 2009 21:13:06 +0000

It also happens around glaciers.