Turkey Earthquake Will Give Clues about the next Big One at San Andreas

In the wake of the devastating earthquake that killed an estimated 11,000 people in Turkey and Syria, scientists from around the world will be flocking to the disaster zone to learn more about the impact that a similar earthquake could have at the San Andreas fault. The East Anatolian Fault, where the Turkey earthquake happened, has many similar properties to the San Andreas fault, which bisects California, making it valuable for seismologists to study for pointers about the long-awaited next "big one" in California. A huge earthquake caused by the San Andreas Fault is thought to be long overdue, although predicting when earthquakes will happen is currently beyond scientists' powers. "In the coming days/weeks, geologists from California (& everywhere else) will arrive in southern Turkey to document, measure, & study the East Anatolian Fault Zone and the effects of these major earthquakes," tweeted California-based geologist and earthquake hazard scientist Brian Olson.

Olson pointed out the similarities between the San Andreas and East Anatolian faults. "Both are strike-slip faults that form part of a major plate boundary," Olson tweeted. "Both have generated M7.8-7.9 earthquakes historically," he said, citing the devastating 7.9 magnitude earthquake that struck San Francisco in 1906, killing 3,000 people, and the equally powerful 1857 Fort Tejon earthquake in California. The San Andreas fault was also to blame for the 1989 6.9-magnitude Loma Prieta earthquake in the San Francisco Bay Area, which killed 63 people. By studying the impacts of the earthquake in Turkey, scientists can learn more about how a "big one"—an earthquake of a similar magnitude at the San Andreas fault in California—might affect the area. The 7.8 magnitude earthquake struck in the early hours of Monday morning, leveling thousands of buildings in Turkey and Syria. The World Health Organization predicts that the death toll could rise to over 20,000 in the coming days. "Of the deadliest earthquakes in any given year, only two in the last 10 years have been of equivalent magnitude, and four in the previous 10 years," Joanna Faure Walker, head of the Institute for Risk and Disaster Reduction at University College London, told the BBC. Olson cautioned that discoveries from the earthquake would not help "predict" earthquakes on the San Andreas Fault. "Earthquake timing is influenced by the unique forces associated with the tectonic plates that are moving on either side of the fault, the shape of the fault zone, and the properties of the rocks at depth along the fault (among many other things)," he told Newsweek. "What we can learn from this earthquake though is how much does this fault zone move and rupture the surface. We can also learn about the effects of strong shaking on the ground, bedrock slopes, coastal areas, infrastructure, etc. The main shock in Turkey was a M7.8 and that is the same magnitude modeled for a major earthquake on the southern San Andreas." The quake's epicenter occurred in Turkey's southeastern province of Kahramanmaras, but shocks were felt as far away as Cairo, nearly 1,000 miles to the southeast. The earthquake was triggered by the two plates that meet at the faultline moving against each other: in this case, the Arabian plate moved northwards against the Anatolian plate.

Earthquakes are measured by the severity of their damage: Below magnitudes of 5.5 to 6.0, there will be light damage to buildings and other structures, while between 6.1 to 7.9, there may be large amounts of damage in very populated areas. At magnitudes of 8.0 or greater, communities near the epicenter may be completely destroyed. The more powerful the earthquake, the more damage that is done to buildings and infrastructure, and the more people die. The most powerful earthquake ever to have been recorded occurred in Chile in 1960, coming in at between 9.4 and 9.6 in magnitude. "Learning from earthquakes anywhere helps us anticipate the effects of earthquakes wherever they occur. Specifically, the similarity of the faults in Turkey to those in California makes understanding these earthquakes particularly important for preparing for the future," Olson tweeted. Experts monitoring seismic activity in the region are concerned that California could be due for a huge earthquake, known as the "Big One", due to large amounts of pressure built up between the static plates of the San Andreas fault. An earthquake of this scale is expected to occur around once every 100 to 220 years. "There are many plausible scenarios for big earthquakes up and down the the San Andreas fault system, including ones that would be highly disruptive in California," Rick Aster, professor of geophysics and department head at Colorado State University, previously told Newsweek. "Large earthquakes on the San Andreas fault system are a geological inevitability, but individual earthquake occurrence over years to millennia is chaotic. It's thus possible to forecast earthquakes probabilistically but not, unfortunately, to predict the size, time and location of individual earthquakes at this time." Around 11,342 buildings are reported to have collapsed in the aftermath of the Turkey quake, 5,775 of which had been confirmed by Turkey's disaster management agency.

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In 2008, seismologist Lucy Jones of the United States Geological Survey (USGS) created the ShakeOut Scenario, which estimated the potential damage caused by an earthquake with a 7.8 magnitude at the San Andreas fault. Their forecasts predicted at least 2,000 fatalities, 50,000 injuries and $200 billion in economic devastation in the aftermath of such an earthquake, with any aftershocks in the proceeding months increasing the damage further. Additionally, fires caused in the wake of the quake are predicted to result in $100 billion in extra damage, and landslides resulting in another $1 billion in damages. By studying how the Turkey earthquake resulted in damage and death, researchers may be able to plan more effectively and possibly reinforce vulnerable points before the Big One hits. "It's really up to us to make sure buildings and infrastructure are safe and reliable when it happens or we will have a much harder time," USGS geophysicist Morgan Page previously told Newsweek. "An earthquake is inevitable but our response to the earthquake is not. We can control how safe buildings and infrastructure is." Do you have a tip on a science story that Newsweek should be covering? Do you have a question about earthquakes? Let us know via science@newsweek.com.