Another earth tremor on the AZ/CA /Mexico Border. It's th 4th one in

[Bobbieo]

3 days. They only last a few seconds but they are kinda scary. Like waiting for the big one.

[aquart]

1. Maybe not.

If the stress is blowing off in little ones, it may not be accumulating to a BIG ONE.

7 credits of geology vaguely retained.

[Bobbieo]

2. I Majored in Geology a long, long time ago but we never had quakes in Tucson.

Hope you are right, aquart. My adobe brick patio wall is about 50 years old and it wouldn't take much to flatten it.

[aquart]

5. Where was the epicenter? Is it on a known fault?

[Bobbieo]

7. I think the epicenter is in Mexicali, BC - the news said it is on the Algodones fault

[aquart]

10. So it's just business as usual.

[phantom power]

4. Every bit of energy released in small quakes...

is energy that won't be released in a big quake. On the other hand, it's a logarithmic scale. So ten 5.0 quakes would only "reduce" a potential 7.0 to a 6.95

It would take 9,000 5.0 quakes to reduce a 9.0 to an 8.0

Never thought about that. Bummer.

[kestrel91316]

13. We had lots of small and moderate quakes in our area

in the five years leading up to Northridge. Other than aftershocks, very little since.

This business down by the border has me a little nervous.

[itsrobert]

3. That was a 5.0

thanks

[silverweb]

6. I'm near the border on the coast.

Too far west to have felt anything. However, I'd rather have a whole bunch of little quakes releasing pent-up energy in those tectonic plates gradually than have it go all in one big rumbler! :D

[Bobbieo]

8. Know what silverweb, so would I!

[shireen]

9. some interesting data at USGS - 10 events since Feb 9.

Since Feb 9th, there have been 10 tremors in the area:

http://earthquake.usgs.gov/eqcenter/shakemap/list.php?y=2008&n=sc

Mag Event ID Name/Epicenter Date Time Lat Lon
4.0 14348592 19.9 mi SE of Calexico, CA Feb 12 2008 04:40:46 UTC 32.444 -115.281
5.0 14348588 17.9 mi SE of Calexico, CA Feb 12 2008 04:32:39 UTC 32.459 -115.314
3.9 14348384 19.3 mi SE of Calexico, CA Feb 11 2008 23:06:04 UTC 32.438 -115.308
3.6 14348248 19.7 mi SE of Calexico, CA Feb 11 2008 19:23:28 UTC 32.438 -115.297
5.1 14348196 27.4 mi SSE of Calexico, CA Feb 11 2008 18:29:30 UTC 32.327 -115.257
3.6 14347460 21.0 mi SE of Calexico, CA Feb 10 2008 01:52:21 UTC 32.423 -115.281
3.6 14346904 20.2 mi SE of Calexico, CA Feb 09 2008 07:43:27 UTC 32.440 -115.277
3.5 14346900 21.3 mi SSE of Calexico, CA Feb 09 2008 07:42:59 UTC 32.401 -115.310
3.8 14346872 19.9 mi SE of Calexico, CA Feb 09 2008 07:28:42 UTC 32.441 -115.286
5.1 14346868 21.6 mi SSE of Calexico, CA Feb 09 2008 07:12:06 UTC 32.406 -115.293

About 6 last year, but spread out over the year. This cluster over the last 4 days is interesting. Any geologists care to comment?

edited to add:
epicenter, latest event.

[Bobbieo]

11. There are really no tall buildings to knock down over the entire area.

which is a blessing. The largest city is Mexicali which is also closest to the epicenter and suffers the worst damage. It is better to have ten litle quakes rather than one big blowout!!!

[XemaSab]

14. Maybe there's magma moving...

:D

[losthills]

12. As weght is taken off the poles,

tectonic activity can be expected to increase worldwide.