I’ve been listening to this odd swarm for a a few days now.
From the www.usgs.gov map
(Zoom in to Southern California, select Settings from the lower left corner to bring upa bar with variable magnitude earthquakes and variable date selection criteria for more “fun” )
I’m disagreeing with this self-selected “expert” in that the USGS site shows the San Andreas Fault going right through this swarm at the south tip of the Salton Sea. Of the recent 1200 earthquakes in the nearby 100 miles region, more than 60% have occurred in the last 3 days (Most, of course, less than Mag 2.5. But still, that’s a large increase in a little area. More like a very focused spot less than 10 miles across - almost like a volcanic magma intrusion (future eruption) than a fault line slip.
Looking at a map, check the Salton Sea’s location and continue that south into the Gulf of California in Mexico. It appears to be a natural breaking point, right where the Colorado River dumps into the Gulf.
there is a cinder cone in that area that erupted IIRC about 8,000 years ago.
When I saw the swarm on the USGS map, I immediately thought about the Iceland earthquakes that preceded the recent volcanic eruption.
Shaken, not stirred.
https://en.wikipedia.org/wiki/Salton_Sea#History
[snip] The Gulf of California would extend as far north as Indio, were it not for the delta created by the Colorado River. Over three million years, through all of the Pleistocene, the river’s delta expanded until it cut off the northern part of the gulf. Since then, the Colorado River has alternated between emptying into the basin, creating a freshwater lake, and emptying into the gulf, leaving the lake to dry and turn to desert. Wave-cut shorelines at various elevations record a repeated cycle of filling and drying over hundreds of thousands of years. The most recent freshwater lake was Lake Cahuilla, also known as the Blake Sea after American professor and geologist William Phipps Blake. It covered over 2,000 square miles (5,200 km2), six times the area of the Salton Sea.
Archaeological sites and radiocarbon dates indicate that the lake was filled three or four times over the last 1300 years. When full, the lake would attract Native Americans to its shores. Hundreds of sites have been found, some possibly long-term villages and other temporary camps. The occupants ate at least four species of fish (two of which were razorback sucker and bonytail chub), birds (particularly the coot), black-tailed jackrabbit, black-tailed cottontail rabbit, and sometimes deer and bighorn sheep. Among the plants they used were bulrush, cattail, mesquite, and saltbush. The Cahuilla people have an oral memory of the last lake, which existed in the 17th century and dried up soon after 1700 AD. [/snip]
There's that word, 'expected', again.......................