San Andreas fault could unleash an earthquake unlike any seen before, study of deadly Myanmar quake suggests
Defects like San Andreas do not necessarily repeat the past behavior, which means that the next major earthquake in California has the potential to be greater than that seen before, suggests a new study.
The new ideas on defects behavior came from the study The Mars devastating earthquake of MyanmarWho killed more than 5,000 people and caused general destruction. Scientists have found that the responsible flaw, a “earthquake superhigle” known as sagain default, has spread in a larger area, and in places they did not expect on the basis of previous events.
Defects are fractures in the crust of the earth. The constraint can accumulate along faults until the defect suddenly breaks, causing an earthquake. Like the defects of Sagaing and San Andreas are similar, what happened in Myanmar could help researchers better understand what could happen in California.
“The study shows that future earthquakes may not simply repeat known earthquakes”, co-author of the study Jean-Philippe Avouacprofessor of geology and mechanical and civil engineering in Caltech, said in a statement. “The successive breaks of a given fault, even as simple as the defects of Sagain or San Andreas, can be very different and can release even more than the shift deficit from the last event.”
In relation: Almost half of California’s faults – including San Andreas – are late for earthquakes
THE San Andreas Fauteur is the longest flaw in California, extending to approximately 746 miles (1,200 kilometers) from the south of the State to the North Salton Sea off Mendocino. In 1906, a break in the northern section of the fault caused a devastating earthquake of 7.9 US Geological Survey.
Earthquakes are notoriously unpredictable, but geologists have long warned that the fault of San Andreas will produce another massive earthquake at a given moment. For example, the area closest to Los Angeles is 60% chance of undergoing a magnitude of 6.7 or more over the next 30 years, According to the USGS.
The 870 -mile long sagaing flaw (1,400 km) is similar to the San Andreas flaw in that they are both long sliding defects, which means that the rocks slide horizontally with little or no vertical movement.
The geologists expected the sagaing flaw somewhere in its extent. More specifically, they thought that the rupture would take place on a section of 190 miles long (300 km) of the fault where no big earthquake had occurred since 1839. This expectation was based on the Hypothesis of the seismic gapwhich provides that a section stuck in a fault – where there has been no movement for a long time – will slip to make up for the place where it was, according to the press release.
However, in the case of sagaing, the shift occurred along more than 310 miles (500 km) of the fault, which means that it has caught up, then some. The researchers used a special technique to correlate satellite imagery before and after the event. These images revealed that after the earthquake, the east side of the flaw moved south of about 10 feet (3 m) compared to the west side. Scientists say that the imaging technique they have used could help improve future earthquake models.
“This earthquake has proven to be an ideal case to apply image correlation methods [techniques to compare images before and after a geological event] who were developed by our research group, “Study First Author Solène AntoineA postdoctoral scholar of geology in Caltech, said in the press release. “They allow us to measure movements on the ground in fault, where the alternative method, radar interferometry, is blind due to a phenomenon such as decorrelation [a process to decouple signals] and a limited sensitivity to North-South travel. “”
