Last Friday, a powerful earthquake shook the ground in California. The 7.1-magnitude seismic event happened near the town of Ridgecrest, causing extensive damage and some minor injuries, but luckily no fatalities. It was the strongest quake registered in the states for 20 years, so strong in fact that the crack it produced has been photographed from space.
The satellite images were collected by Planet Labs who have a fleet of hundreds of satellites that collect images of the Earth’s surface every day. This is useful to many private and public organizations, and, in this case, gives us a bird’s-eye view of the fracture produced by the earthquake.
The quake was the largest one in the current seismic swarm, hitting at 8.19pm local time just outside Ridgecrest, which is located roughly 240 kilometers (150 miles) north-east of Los Angeles. It was quite shallow, happening at just 0.9 kilometers (0.56 miles) below the Earth's surface. It was preceded by a sizable foreshock measuring 6.4 in magnitude, which occurred a day and a half before and came from deeper within the Earth.
Since that initial quake, seismographers in the region have registered over 6,500 earthquakes. The vast majority were only picked up by instruments, although over 360 of them were felt, more or less intensely, by people. Out of those, a handful were magnitude 5 or higher. Those can definitely be felt by people and can even damage buildings.
While locals remain concerned, it is unlikely that another major quake will take place in the immediate future. The United States Geological Survey has released its aftershock forecast and based on the frequency and intensity of the quakes, the chance that an earthquake with a magnitude of 7.1 or higher will strike in the next week is less than 1 percent.
The quakes are concentrated in a series of faults around the region, which are unconnected and quite a distance from the San Andreas Fault, the longest (1,200 kilometers/745 miles) in the state. Many are concerned that an even more powerful earthquake originating from the San Andreas Fault could strike in the future and have devastating consequences. Unfortunately, predicting earthquakes is beyond our current capabilities.