There has been a Heck Of A' Lot 'O Seismic Activity in Southern California lately!
These events are relatively low in Magnitude ("MI") which are typically of 4.2 to 4.8, but there are so many events occurring in the same locations...
To me, it appears as if the Large Faults - such as the San Andreas (Fault boundary between the North American Plate and the Pacific Plate), are being relieved of tension in multiple small "Steps" by releasing stresses in many small 4.2 MI to 5.0 MI Events; rather than releasing the stresses in several very large events (> 7.5 MI)
These could also be fore-shocks... who knows!
The Events nearest to Us (Wife and Me) are on the Chino Fault Line, epicenter apx. 2 Miles from Yorba Linda.
Most recent was on August 29th 2012 at 12:31 PDT.
Event measured 4.1 MI, at a depth of 8.0 kM, at coordinates 33.907N 117.779W.
Closest to epicenter: 3 km (2 miles) NNE (22 degrees) of Yorba Linda, CA.
As with the previous Events, when the P&S Waves arrived, there was an initial hard lateral thrust (like having a rug pulled out under your feet), rapidly subsiding down with "Back And Forth" lateral movements - lasting no more than 5 seconds, then ending with circular rotations for max. 30 seconds.
The initial "Jolts" scared the @#!*&% out of me! Each time, I was in "Full Engineer Mode" (extreme concentration on a given design element), and the room was dead silent!
Here is a list of the Seismic Events which have occurred since April 28 2012:
28 Apr 2012 07:07:27
4.1 MI
34.243N 117.426W
Depth 10 km
3 km (2 miles) NW (316 degrees) of Devore, CA
28 Apr 2012 13:25:07
4.1 MI
19 km (12 miles) SW (236 degrees) of Guadalupe Victoria, Baja California, Mexico
22 May 2012 07:06:24
4.4 MI
14 km (9 miles) S (190 degrees) of Seeley, CA
29 May 2012 21:14:00
4.1 MI
48 km (30 miles) SSW (212 degrees) of Malibu, CA
(Offshore between coast and channel islands)
10 Jun 2012 14:45:43
4.0 MI
64 km (40 miles) WSW (251 degrees) of Guadalupe Victoria, Baja California, Mexico
13 Jun 2012 19:17:15
4.0 MI
33.912N 117.783W
Depth: 5.0 km
3 km (2 miles) N (11 degrees) of Yorba Linda, CA
30 Jun 2012 19:25:20
4.8 MI
21 km (13 miles) WSW (250 degrees) of Guadalupe Victoria, Baja California, Mexico
30 Jun 2012 19:25:23
4.6 Mb
16 km (10 miles) NW (306 degrees) of Guadalupe Victoria, Baja California, Mexico
7 Aug 2012 22:23:34
4.4 MI
2 km (2 miles) NNE (19 degrees) of Yorba Linda, CA
8 Aug 2012 08:33:22
4.5 MI
1 km (1 miles) NNW (348 degrees) of Yorba Linda, CA
--- And The Craziest Of Them All: > 24 Hours of Seismic Activity at One General Location!!! ---
Between 26 Aug 2012 11:16:11, and 27 Aug 2012 18:01:20, there were (18) separate Events, from 4.0 MI to 5.4 MI, in the Salton Sea area, nominally 4 km (2 miles) NW (326 degrees) of Brawley, CA.
This location is the San Andreas Valley, and the Fault Line runs against the foothills located to the northeast.
That's all from Shakeytown!
-- Scott (EE)
