News

A recent study conducted by researchers at the California Institute of Technology (CIT) reveals that the Long Valley Caldera in eastern California is undergoing a period of unrest as its deep magma chamber cools down. This supervolcano last erupted approximately 100,000 years ago, burying modern-day Los Angeles under a kilometer of sediment.

Although the Long Valley volcano currently remains in a relatively sluggish state, seismic activity within the caldera has been observed since the late 1970s. Periods of inflation and deflation of the ground have led to concerns of a supervolcanic eruption. However, the recent findings indicate that the volcano is actually cooling down, rather than preparing for an eruption.

Geophysicist Zhongwen Zhan from CIT explains that the cooling process may release enough gas and liquid to cause earthquakes and minor eruptions. For instance, in May 1980, the region experienced four magnitude 6 earthquakes. This research is based on data collected from a 100-kilometer stretch of fiber optic cable using distributed acoustic sensing. Over the course of a year and a half, more than 2,000 seismic events were cataloged using this network of interconnected sensors.

Using machine learning algorithms, the collected data was transformed into a high-resolution map of the caldera and the underlying volcano. This allowed researchers to observe the separation between the large magma chamber located 12 kilometers below the surface and the shallow hydrothermal system above. As the deeper chamber cools, gases and liquids rise to the surface, potentially causing earthquakes and ground deformation. This phenomenon is different from an active volcanic eruption, where magma forces its way to the surface.

The study represents a groundbreaking use of distributed acoustic sensors to reveal the dynamic processes occurring beneath Earth’s surface. These sensors provided exceptional resolution, allowing researchers to observe layers up to 30 kilometers deep. The research team plans to continue monitoring the volcano’s activity by installing seismic sensors at a depth of 20 kilometers with a 200-kilometer-long cable.

Overall, the findings suggest that the Long Valley Caldera is undergoing a period of restlessness as it enters a phase of cooling. While the risk of a supervolcanic eruption is considered low, the release of gases and liquids may cause earthquakes and minor eruptions. Continued monitoring of the caldera’s activity is crucial for understanding the geological processes at play in this region.

Source: The study was published in Science Advances.

The post The Restless Sleep of California’s Long Valley Caldera appeared first on Fagen Wasanni Technologies.