New USGS findings attributed to Fault Jumping
One consistent thing in the ever changing world of earthquake readiness is the ever-streaming influx of new information. This week’s Rock The Quake will take a look at the latest information from the USGS, and what it means to Californians.
Last week multiple media outlets LA Times and Reading Eagle reported that the probability of an 8.0 or greater earthquake in the state in the next thirty years had nearly doubled. The sad truth is that, news such as this, rarely moves the needle in getting people to take the steps to get earthquake ready. An actual earthquake is the best motivator, and Californians all over the state stepped up readiness efforts following last year’s earthquake in Napa. Studies show earthquake drills and simulations also move the needle in overall earthquake readiness.
The USGS findings moved the probability of a 1906 San Francisco Earthquake-sized event occurring in the next thirty years from four percent to an over seven percent chance. So, the likelihood of this type of earthquake hitting before 2045 is still low. But, as the Northridge, Sylmar and Loma Prieta earthquakes demonstrated, the relation between magnitude of and damage caused by an earthquake is loose at best.
What is fascinating about the new information is that the rise in probability is attributed to a phenomena called “Fault Jumping”. I first heard of this idea described about quake-prone regions in Turkey and then again after the Easter earthquake in Mexicali, when aftershocks seemed to march northward toward the Salton Sea and the San Andreas. Fault Jumping means more than one fault can fracture during a single event, which raises the overall energy release and corresponding magnitude.
When I take a step back and look at the scientific study of earthquakes I realize that it is a relatively new endeavor. We will continue to gain vital knowledge about the nature of earthquakes, with each revelation inspiring folks to take a step toward readiness.
Written by Glen Granholm, VP of Safe-T-Proof Disaster Preparedness Co., Inc.