Hi All. Doing some research today on another topic I came across this.

Strike and alignment of the Imperial fault are nearly concordant with traces of the San Jacinto fault northwest of the Salton Sea. The San Jacinto fault is historically more active than the San Andreas fault south of the Transverse Ranges.

General alignment and historic activity suggest that the Imperial fault may be a southern splay of the San Jacinto fault. A scarp 1 to 2 meters high is locally prominent along segments of the Imperial fault indicating this zone of rupture has been prehistorically active.

The most recent quake activity in the Baja area didn’t do anything to relief the possibility of a major quake there in the immediate future. Indeed it may have increased the possibility of a major quake further north in the Southern California region.

In some ways it sort of reminds me of the relation ship the Rodgers Creek and Hayward faults have. Take Care…Don in creepy town

“Earliest reports of earthquakes in the Southern California/Baja region date back to the middle 1800s and are based on felt reports from San Diego, Yuma, and San Bernardino. More reliable accounts of earthquakes began around the turn of the century when the area became inhabited. On November 29, 1852, based on reported effects in distant towns, a large earthquake is believed to have occurred in the northern Salton Trough, probably in the Imperial Valley. A magnitude of about 6.5 is estimated for this event (Toppozada and others, 1979). On April 18, 1906, only hours after the Great San Francisco earthquake, a large earthquake occurred in Imperial Valley, estimated to be M = 6.0 (Toppozada and others, 1978). No damage was reported as the area was still sparsely populated at the time. However, on June 22, 1915, two earthquakes of M = 6.3 occurred, killing six persons and causing $900,000 in damages in Imperial Valley (Coffman, 1969). Further south in the Salton Trough, below the International Border, on December 30-31, 1914, two large earthquakes (M = 6.5 and 7.1)occurred along what was believed to be the southern extension of San Jacinto fault. It was not until 1940, however, that the Imperial fault was recognized.

On May 18, 1940, at 8:36 p.m. a M = 6.7 (Hileman and others, 1973; M = 7.1 --- Richter, 1958; M = 6.4 --- Trifunac and Brune, 1970) earthquake occurred accompanied by over 40 miles of ground surface rupture extending from northern Baja California to just south of Brawley. This rupture became recognized as the Imperial fault (Buwalda, Richter 1941). Right lateral displacements of up to 19 feet and vertical displacements up to 4 feet were reported between Highway 98 and the International Border (Richter, 1958). Nine persons were killed during this event and structural and agricultural losses accumulated to $6,000,000 (Coffman, 1969).”