After two robust earthquakes hit in California last week, there was a spike in internet searches for Yellowstone caldera and Yellowstone volcano. The quakes—a magnitude 6.4 and 7.1 on July 4 and 5 respectively—had clearly raised fears these events might trigger an eruption on the supervolcano. Associated search terms, in keeping with Google Trends, included “California earthquake” and “the big one, California.”
However, these fears are entirely unfounded, the USGS has mentioned. In a report on the Yellowstone Volcano Observatory web site, scientist-in-charge Mike Poland has defined what affect earthquakes have on volcanic activity—and why the quakes in California won’t trigger Yellowstone to erupt.
He mentioned that strong earthquakes aren’t an uncommon occurrence for the western U.S. The area is roofed in fault lines—an interactive map of them can be found here. Fault lines are cracks within the Earth’s crust, which have the potential to set off earthquakes once they move around.
“Since 1900, within the continental U.S. there have almost 100 earthquakes greater than M6, and there have been nine greater than M7 (each of those numbers go up when you include Canada and Mexico),” Poland wrote. “Most of those events are in California. However, they’ve also occurred in Oregon, Washington, Nevada, Utah, Idaho, Montana, and Wyoming. If we believe that rate is representative of the average, which means there could be about 10 M7+ events per century within the western USA.”