By STACY LIBERATORE, US SCIENCE & TECHNOLOGY EDITOR
Published: 19:08 BST, 21 August 2026 | Updated: 19:38 BST, 21 August 2026
A swarm of earthquakes rattled an active volcanic region in California on Friday.
The US Geological Survey (USGS) recorded seven tremors near Coso Junction by Friday afternoon, with the strongest, a magnitude 3.4, striking at 10.26am PT (1.26pm ET).
The Coso volcanic field, located about 160 km (100 mi) northeast of Bakersfield, is not a single, isolated mountain vent, but is a 150-square-mile cluster containing dozens of individual volcanic features powered by a broad underlying zone of magma.
The region last erupted about 39,000 to 40,000 years ago.
Over the past quarter-million years, the field has experienced roughly 40 distinct individual eruptive events and episodes.
The volcanic field is actively monitored for eruption and unrest by the USGS California Volcano Observatory in cooperation with the US Navy.
Its current alert level is Normal with a Green aviation color code.
The USGS noted that Friday's seismic activity did not establish that the earthquakes were volcanic or indicate an eruption is approaching.
The Coso volcanic field is not a single, isolated mountain vent, but is a 150-square-mile cluster containing dozens of individual volcanic features powered by a broad underlying zone of magma
Only one person reported shaking following the 3.3 magnitude earthquake.
The other six tremors detected were less than 2.5 magnitude, with the first recorded at 7.50am PT.
Two other earthquakes greater than magnitude 2.5 have rattled the region in the past week.
The strongest, a magnitude 3.0, struck the same area before the latest quake, while a magnitude 2.8 was recorded on August 15.