A quake with a magnitude of 7.1 jolted much of California, cracked buildings, set fires, broke roads and caused several injuries while seismologists warned that large aftershocks were expected to continue.

The quake, preceded by Thursday’s 6.4-magnitude temblor in the Mojave Desert, was the largest Southern California quake in at least 20 years and was followed by a series of large and small aftershocks, including a handful above magnitude 5.0.

There is about a 1-in-10 chance that another 7.0 quake could hit within the next week, said Lucy Jones, a seismologist at the California Institute of Technology and a former science adviser at the U.S. Geological Survey.

The chance of a 5.0-magnitude quake “is approaching certainty,” she added.

However, the quake was unlikely to affect fault lines outside of the area, Jones said, noting that the gigantic San Andreas Fault was far away.

The quake struck at 8:19 p.m. and was centered 11 miles from Ridgecrest in the same areas where the previous quake hit. 

“These earthquakes are related,” Jones said, adding that the new quake probably ruptured along about 25 miles of fault line.

The quake was felt as far north as Sacramento, as far east as Las Vegas and as far south as Mexico.

Latest #RidgecrestQuake data from @USGS. https://t.co/NuaxdKb3Hxpic.twitter.com/HFtIaAmEcI

— Steve Herman (@W7VOA) July 6, 2019

Early magnitude estimates from the U.S. Geological Survey wavered between 6.9 and 7.1. It was measured at 7.1 by the 
European-Mediterranean Seismological Agency.

Multiple injuries, fires

The area in and around Ridgecrest, trying to recover from the previous temblor, took the brunt of damage.

Megan Person, director of communications for the Kern County Fire Department, said there were reports of multiple injuries and multiple fires, but she didn’t have details.

The county opened an emergency shelter. Meanwhile, a rockslide closed State Route 178 in Kern River Canyon, where photos from witnesses also showed that a stretch of roadway had sunk.

San Bernardino County firefighters reported cracked buildings and one minor injury.

In downtown Los Angeles, 150 miles away, offices in skyscrapers rolled and rocked for at least 30 seconds.

Gov. Gavin Newsom activated the state Office of Emergency Services operations center “to its highest level.”

“The state is coordinating mutual aid to local first responders,” he said.

Lucy Jones, a seismologist at the California Institute of Technology and a former science adviser at the Geological Survey, tweeted that Thursday’s earthquake was a “foreshock” and that Friday’s quake was on the same fault system as the earlier quake.

This is the same sequence. You know we say we 1 in 20 chance that an earthquake will be followed by something bigger? This is that 1 in 20 time

— Dr. Lucy Jones (@DrLucyJones) July 6, 2019

“You know we say we have a 1 in 20 chance that an earthquake will be followed by something bigger? This is that 1 in 20 time,” she tweeted.

Firefighters around Southern California were mobilized to check for damage.

An NBA Summer League game in Las Vegas was stopped after the quake. Speakers over the court at the Thomas & Mack Center continued swaying more than 10 minutes after the quake.

In Los Angeles, the quake rattled Dodger Stadium in the fourth inning of the team’s game against the San Diego Padres.

The quake Friday night happened when Dodgers second baseman Enrique Hernandez was batting. It didn’t appear to affect him or Padres pitcher Eric Lauer.

Like any quake, today’s M7.1 has a 1 in 20 of being followed by something even bigger. Smaller quakes – M5s are likely and a M6 is quite possible.

— Dr. Lucy Jones (@DrLucyJones) July 6, 2019

Hours earlier, seismologists had said that quake had been followed by more than 1,700 aftershocks and that they might continue for years. 

Jones said aftershocks from the new main quake could occur for three years.

Changes to alert system

Earlier Friday, Los Angeles had revealed plans to lower slightly the threshold for public alerts from its earthquake early warning app. But officials said the change was in the works before the quake, which gave scientists at the California Institute of Technology’s seismology lab 48 seconds of warning but did not trigger a public notification.

“Our goal is to alert people who might experience potentially damaging shaking, not just feel the shaking,” said Robert de Groot, a spokesman for the USGS’s ShakeAlert system, which is being developed for California, Oregon and Washington.

Construction of a network of seismic-monitoring stations for the West Coast is just over half complete, with most coverage in Southern California, San Francisco Bay Area and the Seattle-Tacoma area. Eventually, the system will send out alerts over the same system used for Amber Alerts to defined areas that are expected to be affected by a quake, de Groot said.

California is partnering with the federal government to build the statewide earthquake warning system, with the goal of turning it on by June 2021. The state has spent at least $25 million building it, including installing hundreds of seismic stations throughout the state.

This year, Newsom said the state needed $16.3 million to finish the project, which included money for stations to monitor seismic activity, plus nearly $7 million for “outreach and education.” The state Legislature approved the funding last month, and Newsom signed it into law.

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