Large magma reservoir discovered beneath Long Valley supervolcano

The Long Valley supervolcano erupted 760,000 years ago, forming a massive caldera. Since 1978, uplift in the caldera center suggests magma inflow. Seismic tomography by USGS researchers revealed a detailed view of the subsurface, showing a reservoir with 240 cubic miles of semi-molten magma, 27% of which is liquid.

What major geological event occurred 760,000 years ago at the Long Valley supervolcano?

• A massive earthquake

• A significant volcanic eruption

• A large meteor impact

• A major flood

What was the result of the Long Valley supervolcano eruption?

• Emergence of a new island

• Formation of a mountain range

• Development of a desert

• Creation of a massive caldera

What has been observed in the caldera center since 1978?

• A decrease in volcanic activity

• A gradual uplift

• A sudden collapse

• A new volcanic eruption

What technique did researchers use to study the subsurface of the supervolcano?

• Ultrasound scanning

• Seismic tomography

• Magnetic resonance imaging

• X-ray diffraction

What percentage of the magma reservoir beneath the supervolcano is in a liquid state?

• 50%

• 27%

• 15%

• 75%