California earthquake swarm occurs near the Salton Sea
Officials in Southern California recorded 142 earthquakes along the southern San Andreas Fault beginning Monday, September 26. The earthquakes generated near cross-faults that run north/northeast under the Salton Sea. The orientation of the cross-faults may add to stress on the San Jacinto and San Andreas Faults should they rupture.
The swarm of earthquakes prompted the Governor’s Office of Emergency Services to [link url=”http://www.upi.com/Top_News/US/2016/09/30/California-warns-of-possible-stronger-quake-after-earthquake-swarm-in-Salton-Sea/1821475228314/” title=”issue an alert for residents”] regarding the possibility of a larger quake, which is considered long overdue in the area.
Scientists have puzzled over why, even though significant stress has built up along the southern most portion of the San Andreas Fault – with earthquakes generally occurring along this portion of fault about every 300 years – the last major earthquake along this fault was in 1690.
A group of scientists may have found the answer.
Scientists discover a new fault
A [link url=”http://www.bssaonline.org/content/106/5/1963″ title=”recent study”] titled Geophysical Evidence for a San Andreas Subparallel Transtensional Fault along the Northeastern Shore of the Salton Sea indicated that a newly discovered fault line under the Salton Sea may alter current area-wide seismic hazard models.
The newly discovered fault, the Salton Trough Fault (STF), runs parallel to the San Andreas Fault. Scientists found the fault through the use of [link url=”http://www.techtimes.com/articles/181116/20161006/scientists-discover-new-fault-along-southern-california-s-salton-lake-parallel-to-san-andreas.htm” title=”marine seismic equipment”] that helped scientists accurately map patterns of deformation in sediment layers that exist in the sea and around its bottom.
Based on captured deformation patterns, the scientists who conducted the study believe that the pressures from the larger southern San Andreas Fault were likely absorbed somewhat by the newly discovered fault. The researchers cautioned, however, that further research into the STFs role and interaction with the San Andreas Fault — and the danger it poses — is necessary to understand this new fault line.
Researchers also indicated that no past earthquakes has ever been attributed to the fault.
According to [link url=”http://www.bssaonline.org/content/106/5/1963″ title=”the study”]: “From a seismological hazards perspective, the presence of this structure could alter the current understanding of stress transfer and rupture dynamics in the region, as well as community fault models and ground‐motion simulations on the SSAF.”
According to study scientists, the announcement of the fault line discovery just after the small swarm of earthquakes occurred in the area was merely coincidental, and the newly discovered Salton Trough Fault was not linked in any way to that swarm.
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