Want to get a sense of just how much seismic activity exists in the state of California? A new video from the Pacific Tsunami Warning Center maps every earthquake recorded in or around the Golden State in the last 30 years.
Ending with the July 5 magnitude 7.1 quake in Ridgecrest, the video displays thousands of seismic events, mapped as colorful circles with diameters proportionate to Richter scale measurements and colors that convey the depth of the rupture that produced the quake.
The animation begins in August 1989. A large blue circle pops up in the first few seconds, representing the magnitude 6.9 Loma Prieta earthquake, which wreaked havoc on the Bay Area as the San Francisco Giants and the Oakland Athletics prepared for game three of the 1989 World Series.
Loma Prieta was the deadliest temblor of the last 30 years, but the slightly smaller 1994 Northridge earthquake (magnitude 6.7) caused far more property damage and injured 9,000 people.
In terms of sheer scale, the largest earthquake in the last three decades was the magnitude 7.3 quake that rocked the small Mojave Desert town of Landers in June 1992. Earlier that year, an earthquake only slightly smaller in scale (magnitude 7.2) shook the coast of Northern California, near Cape Mendocino. It’s the only California tremor in the last 30 years to trigger a major tsunami.
But these large events represent only a tiny fraction of the many earthquakes that shape California’s geologic landscape almost daily. As illustrated by the composite image shown in the video’s final seconds, faults capable of producing major earthquakes snake through most of the state—and rupture routinely.