A study from the California Institute of Technology (CIT) suggests that the Long Valley Caldera in eastern California is experiencing restlessness. The volcano, which last erupted over 100,000 years ago, began generating earthquakes in the late 1970s and caused persistent seismic activity. The cooling process may release enough gas and liquid to cause earthquakes and small eruptions, as seen in the four magnitude 6 earthquakes in May 1980. The study used dispersed acoustic sensing data from a 100-kilometer fiber optic connection to record over 2,000 seismic occurrences over a year and a half. A high-resolution map of the caldera and the underlying volcano was generated using this data and a machine learning algorithm. The findings show that gases and liquids rise to the surface when the deeper magma chamber cools, leading to earthquakes and ground inflation. The research team is now gearing up to take last readings of the Supervolcano in California as its activity levels decline.
The Long Valley Caldera: A Slumbering Giant
Located in California’s east, the Long Valley Caldera is a volcanic caldera with a long and fascinating history. The last time this volcano erupted was a whopping 100,000 years ago, and the resulting ashfall buried what is now Los Angeles beneath a km of dirt. The massive Supervolcano in California has slowed down considerably, but that doesn’t mean it’s quiet.
The caldera, a depression that hides the submerged volcano, began generating earthquakes in the late 1970s. For decades, the ground was inflated and deflated due to persistent seismic activity.
Is There Reason to Worry?
Fortunately, this isn’t always a sign of catastrophe to come. The knowledgeable staff at CIT has offered a more comforting rationale for the current happenings. Zhongwen Zhan, a geophysicist, “We don’t think the region is gearing up for another supervolcanic eruption, but the cooling process may release enough gas and liquid to cause earthquakes and small eruptions.” Take the four magnitude 6 earthquakes that struck in May of 1980 as an example.
The results are based on dispersed acoustic sensing data from a 100-kilometer fibre optic connection. Caltech scientists used this vast network, the equivalent of 10,000 individual seismometers, to record more than 2,000 seismic occurrences over the course of a year and a half, the vast majority of which would have gone unreported by individuals on the ground.
A High-Resolution Glimpse into Earth’s Interior Dynamics
A high-resolution map of the caldera and the underlying volcano was generated using this data and a machine learning algorithm to help scientists better understand what lies beneath the earth’s surface. Caltech seismologist and lead author Ettore Biondi says their finding is groundbreaking since it is the first time a network of widely spaced acoustic sensors has revealed the inner workings of Earth.
To a depth of 8 km, the generated images have an extraordinary lateral resolution, and to a depth of 30 km, the images remain detailed. This new information shows that the huge magma chamber, located 12 kilometres below the surface, is physically distinct from the hydrothermal system located above it.
The Boiling Cauldron: Unveiling the Truth
Gases and liquids rise to the surface when the deeper magma chamber cools. Earthquakes and ground inflation may be a result of this shift. The surface deformation and elevated seismic activity are probably caused by this bubbling effect.
Do not mix this with the cataclysmic eruptions that can occur from active volcanoes. In contrast to an active volcanic eruption, in which magma pushes its way into the upper crust and bursts out, seismic activity in Long Valley shows that a solidified lid of crystallised rock has covered the top of the magma chamber over time.
A Slowing Heartbeat
The research team is gearing ready to take last readings of the Supervolcano in California as its activity levels decline. Using a seismic sensor cable stretching 200 km, they intend to explore to a depth of 20 kilometres. As this geological behemoth enters what may be a lengthy slumber, this information will be invaluable.
No need to panic; the Long Valley Caldera is just getting restless. Recent seismic activity has been related to the cooling process, and scientists think that an explosive supervolcanic eruption is quite unlikely. Thanks to this groundbreaking study about Supervolcano in California, we now have a clearer picture of the inner workings of our planet and can track the activity of these geological marvels with greater precision than ever before.
Could the Long Valley Caldera erupt again in the future?
Despite the intrigue, geologists do not believe the current seismic activity portends a supervolcanic eruption. It is likely that the cooling process is to blame for the observed behaviours.
What is the significance of the distributed acoustic sensing technology used in this study?
Using distributed acoustic sensing technology, scientists were able to build high-resolution maps of the caldera and the underlying volcano, giving them a penetrating view at the inner workings of our planet.
How does the Long Valley Caldera differ from active volcanoes in terms of seismic activity?
Unlike current volcanic eruptions, in which magma makes its way to the surface, the seismic activity at the Long Valley Caldera shows that the magma chamber has a cemented cover.
Is there any immediate danger to the surrounding area due to the recent seismic activity?
While earthquakes are always a cause for concern, the experts agree that the current level of seismic activity in the Long Valley Caldera poses no immediate threat.
What are the implications of this research for our understanding of supervolcanoes and geology?
Insights gained from this study will be useful in future geological investigations and risk assessments of what happens during the cooling phase of supervolcanoes.