Researchers have discovered that earthquakes can 'jump' from one fault to another one that's close by. This is bad news for Californians as the entire state is crisscrossed with fault lines.
The scientists highlight a particularly bad scenario for Los Angeles where several thrust faults are close together increasing the possibility of double the devastation if one fault, where the earthquake starts, triggers a second earthquake in a connecting or close by fault under a minute later.
One potential bad scenario involves a single earthquake spreading between the Puente Hills thrust fault, which runs under downtown Los Angeles, and the Sierra Madre thrust fault, located close to Pasadena, said Gareth Funning, an associate professor of earth sciences at UC Riverside, and a co-author of a paper published online today (Feb. 8, 2016) about the research in the journal Nature Geoscience.
Many other areas could also be implicated by the findings. the New Madrid fault runs through Missouri, Arkansas, Tennessee, Mississippi, Indiana, Illinois and Kentucky and is six times larger than the San Andreas fault. There are many smaller faults in some of these areas and the region is known as The New Madrid seismic zone. In 1811-1812 three earthquakes occurred in the NMSZ, they were thought to be between a magnitude 7 and 8 on the Richter Scale. an eyewitness account states:
“The surface of the earth rose and fell like the long, low swell of the sea, tilting the trees until their branches interlocked, and opening the soil in deep cracks... landslides swept down the steeper bluffs and hillsides; considerable areas were uplifted, and still larger areas sunk and became covered with water emerging through fissures ... high banks [of the Mississippi] caved and were precipitated into the river; sand bars and points of islands gave way, and whole islands disappeared.” (source)
A large area in the southeast of Missouri was changed by these quakes. New streams and islands appeared, lakes were found where previously there were none.
With the Ring of Fire currently showing an uptick in activity, this doesn't bode well for the densely populated West Coast of the United States.
One earthquake in a city with a population of almost 4 million people is terrifying, the thought that another one of a similar magnitude could happen within seconds a few miles away is a nightmare scenario.
By studying the Pakistan earthquake of 1997 the researchers found that what was originally thought to be a 7.1 quake was actually two quakes, some 30 miles apart, the first a 7.0 and the second, following just 19 seconds later, a 6.8.
'Doublet' earthquakes have the potential to cause massive devastation over a much wider area than was previously thought. aside from the loss of life, which would be huge, particular if a couple of major hospitals were out of commission, the economic effects would be profound, particularly in an area such as California that produces a high proportion of the fruits and vegetables consumed in the United States. Food prices would rise and even those lucky enough to be thousands of miles from the quake would see their squeezed pay checks getting squeezed even more to put the food on the table for their families.
The longer the stresses build up the higher the chance of having a large magnitude quake when the fault does slip. Let's hope the pressure waves stop short of triggering a doublet quake on a nearby fault in a nearby city because that means that emergency assistance will have two disaster areas to cope with at the same time.