Watch as Ridgecrest earthquake shatters desert floor in stunning before-and-after images
The images are among the best of their kind in decades for California.
Millions felt the shaking from the Ridgecrest earthquake.
But new satellite images offer a dramatic and instructive view of the immense power of the magnitude 7.1 quake, showing how California’s biggest earthquake in nearly two decades caused the ground to break.
Animated slides show how the quake permanently jolted a huge block of earth along the fault away from the other.
Some of the clearest images show long scars on the surface of the Mojave Desert, showing precisely the movement of the 30 miles of earthquake fault — oriented in a northwest-southeast direction — that moved within moments on July 5.
Before-and-after satellite images show how one block of ground slid past the other in the Ridgecrest magnitude 7.1 earthquake of July 5. (Sotiris Valkaniotis / Google Earth / DigitalGlobe)
Some of the most widely circulated before-and-after GIFs that have been receiving much attention by California earthquake scientists were created using imagery from Google Earth and DigitalGlobe by an earthquake geologist based in Greece, Sotiris Valkaniotis, who collaborates with the National Observatory of Athens.
In a large section of the fault, images show how land on one side of the fault moved between three and 13 feet from the other, Valkaniotis said.
A long scar in the earth can be seen where one chunk of land jolts past the other along a fault in the Ridgecrest magnitude 7.1 earthquake of July 5. The dark stain is liquid leaking from a pipeline that had straddled the fault and broke when the fault ruptured. (Sotiris Valkaniotis / Google Earth / DigitalGlobe)
The animations are an impressive example of what California has undergone for millennia. California sits on the edge of two gigantic tectonic plates — the Pacific and North American. A huge swath of California, from Santa Cruz to Santa Barbara, L.A. and San Diego, are moving northwest toward Alaska relative to the other plate, which is moving southeast toward Mexico.
A huge swath of ground moved along a fault past the other side during the July 5 magnitude 7.1 Ridgecrest earthquake. (Sotiris Valkaniotis / Google Earth / DigitalGlobe)
California isn’t being just cleanly sliced along the San Andreas fault. There’s a whole array of faults slicing up the state in ribbons, and the fault that ruptured in the Ridgecrest quake on July 5 was doing its job of moving the southwestern side of land from the fault toward Alaska.
The images are among the best of their kind in decades for California. For one, the earthquakes occurred in the desert — perfect to identify the trace of a moving fault without buildings or trees obscuring cracks in the earth. “It’s easier to identify,” Valkaniotis said of seeing the fault rupture in a telephone interview Sunday.
“There is no vegetation … aerially, there are no land use changes,” he said. Similar efforts to do the same by satellite for a strong earthquake months ago in Papua New Guinea were frustrated by the region being covered in tropical vegetation, obscuring the ruptured fault from the air.
The fault responsible for the magnitude 7.1 Ridgecrest earthquake is instantly recognizable by comparing satellite images taken before and after the July 5 quake. (Sotiris Valkaniotis / Google Earth / DigitalGlobe)
The last two biggest and comparable quakes to hit the Mojave Desert in Southern California were the 1992 magnitude 7.3 Landers earthquake and the 1999 Hector Mine magnitude 7.1 quake. But it would be years following those quakes before similar before-and-after comparisons were done, Valkaniotis said.
Ground rupture was observed after the 2014 magnitude 6 Napa earthquake, but the ground displacements were much smaller, owing to the far less powerful nature of that quake. The July 5 magnitude 7.1 Ridgecrest quake was 45 times more powerful than the Napa quake.
Dark lines show the boundary where the ground suddenly moved in the magnitude 6.4 Ridgecrest earthquake on July 4. (Sotiris Valkaniotis / Google Earth / DigitalGlobe)
The higher the magnitude, the greater the distance two sections of land can move away from each other in a quake. One famous example observed in the great 1906 magnitude 7.8 earthquake that leveled San Francisco was at Point Reyes in Marin County, in which a fence that intersected the fault was suddenly cut in two, separated on each side of the San Andreas by 18 feet.
A similar sized quake along the southern San Andreas fault near Palm Springs would produce even greater fault movement. If a couple had the misfortune of holding hands across the fault in a remote part of the desert near Desert Hot Springs when a hypothetical magnitude 7.8 quake hits, they’d suddenly be separated by as much as 30 feet — almost the entire length of a city bus, U.S. Geological Survey research geophysicist Kate Scharer said in 2017.
Dark lines show the location of the fault that moved during the magnitude 6.4 Ridgecrest earthquake of July 4.(Sotiris Valkaniotis / Google Earth / DigitalGlobe)
Not all cracks in the ground seen after an earthquake are directly related to fault movement — sometimes, cracks can be caused by liquefaction or landslides, for instance. But in this case, there were plenty of cracks in the ground directly related to fault movement, Valkaniotis said.
Anything sitting on top of an earthquake fault can be destroyed when one side of the fault moves past the other. California law generally bars new construction directly on top of earthquake faults.
Seismologist Lucy Jones praised Valkaniotis for the GIFs, one of which showed the results of a leaking pipeline damaged at the precise location where it crossed the fault. It broke when the ground on one side of the fault moved away from the other.
Jones said the image illustrated precisely what happens when pipes cross faults.
“When infrastructure crosses faults, we know exactly where it will break,” Jones tweeted. “Imagine if this were a petroleum pipeline. Or your internet fiber optic cable.”