Hayward fault "locked and loaded" for 6.7-7.0 earthquake

[David]

Originally Posted by irishgrl

thats easy. he's formulating jabborwock type messages that will keep us all entertained until the next century.......maybe.

I no Jabborwock!!

Here's what Susan Hough (USGS) says about the Hayward Fault:

"In the East Bay, the Hayward Fault is thought to be capable of generating earthquakes upwards of M7, & it runs through the heart of Oakland & Berkeley. Because ground motions immediately adjacent to a fault rupture are known to be especially severe, the hazard associated with the Hayward Fault is substantial because of the high population density immediately along the fault."

Hough says later on:

"Is California prepared for the many Big Ones that it ultimately will face? Relatively speaking, the answer is yes. The state's building codes & standards are among the best in the world. Yet the fact remains that California has not been tested by the worst that the earth can produce. California has not faced a Big One since the state emerged as the most populous in the nation, home to a diverse & increasingly high-tech economy."

Susan Hough's point is a good one: The last "Big One" in California was the 1906 quake, which was about a magnitude 7.8, more or less. The city of San Francisco was highly populated in 1906, but I'm not sure the surrounding region was. It certainly wasn't to the extent it is today. Bigger population generally means more casualties & more damage, obviously. (The biggest quake in California recorded history -- in 1857 -- only killed five or six people because practically nobody lived in that region yet.)

If I lived in the Bay Area (including East Bay & South Bay, with their San Andreas, Hayward, Calaveras & other faults), I'd take some steps to prepare for medium & large quakes.

San Andreas can generate much larger magnitude quakes than Hayward (remember that longer rupture equals greater magnitude), but an M6.5 to M7 is big! It will kill people & it will damage infrastructure.

I don't know whether the entire Hayward Fault is expected to unzip in a single event, though (which sounds like what happened in 1868 to generate an M6.9).