New study shows less seismic activity of San Andreas due to drying lake

Los Angeles, June 8

The southern San Andreas fault in California has seen less earthquakes in the past hundreds of years, a new study said, while suggesting that the lack of seismic activity may be due to the drying of the nearby lake, Salton Sea.

Hydrologic loads can stimulate seismicity in the Earth's crust. However, evidence for the triggering of large earthquakes remains elusive, according to the study published in Nature.

The study investigated earthquake activity along the southern San Andreas fault over the last 1,000 years, reports Xinhua news agency.

Collecting field data from rocks near the fault, a team from San Diego State University found earthquakes occurred about every 180 years, give or take 40 years, and coincided with high water levels of the nearby ancient Lake Cahuilla, formed in the region of the present-day Salton Sea.

The model may be applicable to other regions in which hydrologic loading, either natural or anthropogenic, was associated with substantial seismicity, according to the study.

The US Geological Survey estimates there is about 60 per cent probability that an earthquake at a magnitude of 6.7 or greater could occur in the next 30 years in the Los Angeles area.