The first quake hit San Francisco Bay area at 5:33 a.m. and only eight seconds later the second one shook the same location. A 2.2 magnitude aftershock came thirty minutes later. The earthquakes went as deep as 5 miles and a half.
According to the seismologists with the U.S. Geological Survey the quakes developed on the Hayward Fault. These two words are dreaded by everybody in the San Francisco Bay area and each seismic activity reminds people residing in the region the earth under their feet isn’t exactly stable.
The Hayward Fault is anything but still. The fault is moving about 9 millimeters each year, and if that would seem insignificant for the lay person, seismologists and geologists have a much grimmer point of view.
Plus, each earthquake makes people wonder if the next will be what the scientists call the Big One. In 2003 a report from the U.S. Geological Survey estimated that within the next 30 years, the Bay Area will be hit by the infamous Big One. According to their statistical data, there were 67 percent chances the Hayward Fault would release a magnitude 6.7 or higher earthquake that would hit Northern California.
Brad Aagaard is a research geophysicist with the U.S. Geological Survey. He declared that the latest tremor moved the Hayward fault 10 centimeters, given the 5.5 miles depth. “Having a small event like this one does change the stresses in the area” he added and since there’s no exact way to predict when the Big One will hit, “it could take place tomorrow, or it could be happening right now”.