A dense network of seismometers has revealed how the underground ruptures during an earthquake, providing new insights into the complex processes that occur beneath the Earth's surface. The study, published in the journal Nature, used data from over 500 seismometers to create a detailed map of the rupture process of the 2019 Ridgecrest earthquake sequence in California.

The results show that the earthquake ruptures occurred in a series of complex, cascading events, rather than a single, simple rupture. This new understanding could help scientists better understand and predict future earthquakes.

The Ridgecrest earthquake sequence began on July 4, 2019, with a magnitude 6.4 earthquake. This was followed by a series of smaller earthquakes, including a magnitude 7.1 earthquake on July 5. The earthquakes caused significant damage to the Ridgecrest area, including collapsed buildings and power outages.

The dense network of seismometers used in the study was installed by the Southern California Seismic Network (SCSN). The SCSN is a collaborative project between the California Institute of Technology and the United States Geological Survey. The network consists of over 500 seismometers that are spread throughout Southern California.

The data from the SCSN seismometers allowed the researchers to create a detailed map of the rupture process of the Ridgecrest earthquake sequence. The map shows that the ruptures occurred in a series of complex, cascading events. This new understanding could help scientists better understand and predict future earthquakes.

"The Ridgecrest earthquake sequence was a complex event that involved multiple ruptures on different faults," said Dr. Zachary Ross, the lead author of the study. "Our study provides a detailed look at how these ruptures occurred, and it could help us better understand and predict future earthquakes."

The study also found that the ruptures occurred at a depth of about 10 kilometers (6 miles). This is shallower than most other earthquakes in the region, which typically occur at depths of 15 to 20 kilometers (9 to 12 miles). The shallower depth of the Ridgecrest earthquake sequence may have contributed to the significant damage that it caused.

"The shallow depth of the Ridgecrest earthquake sequence meant that the shaking was more intense at the surface," said Dr. Ross. "This may have contributed to the significant damage that the earthquake caused."

The study provides new insights into the complex processes that occur beneath the Earth's surface during an earthquake. This new understanding could help scientists better understand and predict future earthquakes, and it could also help to improve earthquake-resistant building design.