distance from the hayward fault (...or any fault) (Berkeley, San Mateo: house, earthquake)

[kiddiepool]

hey all

i've had a question about earthquake damage for years and years, and i'm wondering if one of you might be able to point me in the right direction. i've googled around about this but can't find anything that speaks to it (or i don't know the right words to search for!).

so: i understand the general principle that being farther away from the fault line of an earthquake is better than being closer.

but in city terms, what scale are we talking about?

is a house five blocks away from a fault less likely to be damaged than a house one block away?

how about ten blocks, twenty blocks?

in other words, when does distance from a fault line start to matter in terms of likely damage?

or am i thinking about this wrong?


(specifically along the hayward, i imagine that topography/geology plays a role as well, though i'm not sure in what way. the west side of the fault slopes downhill to the berkeley/oakland flats while the east side continues upward to tilden, sibley, etc.)

[HockeyMac18]

Originally Posted by kiddiepool

hey all

i've had a question about earthquake damage for years and years, and i'm wondering if one of you might be able to point me in the right direction. i've googled around about this but can't find anything that speaks to it (or i don't know the right words to search for!).

so: i understand the general principle that being farther away from the fault line of an earthquake is better than being closer.

but in city terms, what scale are we talking about?

is a house five blocks away from a fault less likely to be damaged than a house one block away?

how about ten blocks, twenty blocks?

in other words, when does distance from a fault line start to matter in terms of likely damage?

or am i thinking about this wrong?


(specifically along the hayward, i imagine that topography/geology plays a role as well, though i'm not sure in what way. the west side of the fault slopes downhill to the berkeley/oakland flats while the east side continues upward to tilden, sibley, etc.)

I think you need to be looking at "miles away from the fault" vs. a few blocks. Within a mile, there probably isn't a major discernible difference in shaking intensity during a quake. If you're looking at a few different places, and they're only separated by blocks, I probably wouldn't look at this as a major deciding factor.


Your last point touches on a very important issue, though - and that is the differences in shaking intensity based on the type of soil you live on top of. If you live on top of bedrock, your shaking might be fairly mild. Even if you live near the epicenter of a quake. But if you live on filled in land (some areas near the bay, such as the Marina district or parts of SOMA and Mission Bay in SF), your shaking intensity can be quite strong. Even if you live far away from the epicenter of a quake.


As an example, I used to live in Alameda, somewhat near the old base there. The land I lived on was filled in land. I felt a few quakes in my short time there. Most of those quakes I came to learn weren't felt by anyone else I knew that lived elsewhere (mainly because they were very mild quakes). In my time since, I have lived in SF and San Mateo, and I've only felt two quakes since. There have been a number of quakes that have happened in the region since, but since I live on bedrock the shaking intensity for where I live is mild compared to people in other parts of the Bay Area and I didn't feel them as a result.

Some information about possible shaking intensities in different parts of the Bay Area:
https://geomaps.wr.usgs.gov/sfgeo/li...ptibility.html

Earthquakes « ABAG Resilience Program

[NextStage]

This is just my opinion and not based on anything scientific - but I think it probably has a lot to do with the way the fault shifts during a quake. One or two miles in one direction could feel radically different than one or two miles in a different direction.

Our house isn't huge - but we've noticed a definite difference in the way a quake feels in one part of the house vs another. We're a rectangular single story and something that will be a serious jolt on one end of the house will be just a tremor on the other end.

As HockeyMac mentions, the type of soil you live on makes a substantial difference as well.

[BayAreaHillbilly]

I'm very, very close to the SAF and nearly right on top of the "Foothills" thrust fault band. But I'm on metamorphic rock. I'm very happy with this location. Meanwhile you couldn't pay me enough to live longer than it took me to flip the place somewhere like Foster City. I wouldn't ever tolerate a place in The Marina.

[phantompilot]

Check out the app Temblor, its made to address this very question.

[kiddiepool]

thanks for your perspectives. a lot to look into.

[zugor]

THere's a link to info from the USGS:

https://earthquake.usgs.gov/learn/to...tions/hayward/

Living near the Hayward Fault is one of the things I DON'T miss at all.

Suggestion - Consider supporting this group: https://searchdogfoundation.org/

Hope all the faults remain quiet for a very long time.

[silverkris]

Well, sometimes it's impractical to move something that's near or on a fault. California Memorial Stadium in Berkeley is located right on the fault - and the 2011 renovation was made with seismic retrofits. Such as putting shock absorbers in the structure.

Memorial Stadium gets renovated with help from Berkeley’s own | Berkeley News