Expected future development of this activity: In the past these types of swarms have continued for many days. Previously, events of up to M6.2 have occurred on northeast striking cross faults, but bigger events are possible on the major northwest striking late Quaternary faults in this vicinity.
Originally posted by TrueAmerican
I have received a second, what appears to be a low level LP at station GLA.
GULF OF CALIFORNIA
2012-08-27 23:16:04.0 UTC
30.68 N ; 113.82 W
358 km SW Phoenix (pop 1,428,509 ; local time 16:16:04.3 2012-08-27)
218 km SE San luis río colorado (pop 139,254 ; local time 16:16:04.3 2012-08-27)
76 km S Puerto peñasco (pop 33,875 ; local time 16:16:04.3 2012-08-27)
Source parameters not yet reviewed by a seismologist
The Salton Trough is a deep sedimentary basin filled primarily with Colorado River sediments formed by the extensional forces associated with an underlying tectonic plate boundary. The spreading-type plate boundary of the East Pacific Rise terminates at the southern end of the Salton Sea where the plate boundary transitions into the transform-type San Andreas Fault plate boundary. High heat flow and recent volcanic activity at the southern end of the Salton Sea indicate that this region is not only modernly active but reveal the location of the northernmost spreading center of the East Pacific Rise.
The Salton Trough has been filled, for the most part, by sediments carried by the Colorado River. These sediments are more than four miles thick in some places. The great pile of sediments carried by the Colorado River eventually built a barricade to the river's flow and the Colorado River was diverted away from the Salton Trough. The Salton Sea is a mistake. At the beginning of the 20th Century, engineers tried controlling the Colorado River flow but a couple of rainy years caused the river to break its levees and flow again into the Salton Trough.
The curious thing is that these quakes, and the fault zone region are at very low altitude, nearly sea level (and below). In fact, it seems as though a significant tear in the earth in this region could conceivably cause sea water from the Gulf of California to rush inland, possibly all the way up into California, the Salton Sea. That would be an extreme event, for sure, but it’s curious to note the possibility.