Titanic Volcano Stopped a Mega-sized Earthquake
In April, pent-up stress along the Futagawa-Hinagu Fault Zone in Japan began to unleash a magnitude 7.1 earthquake. The rupture traveled about 30 kilometers along the fault until it reached Mount Aso, one of Earth’s largest active volcanoes. That’s where the quake met its demise, geophysicist Aiming Lin of Kyoto University in Japan and colleagues report online October 20 in Science. The quake moved across the volcano’s caldronlike crater and abruptly stopped, the researchers found.
Geophysical evidence suggests that a region of rising magma lurks beneath the volcano. This magma chamber created upward pressure plus horizontal stresses that acted as an impassable roadblock for the seismic slip powering the quake, the researchers propose. This rare meetup, the researchers warn, may have undermined the structural integrity surrounding the magma chamber, increasing the likelihood of an eruption at Aso.
Jupiter’s Surprising Depths
Jupiter’s clouds have deep roots. The multicolored bands that wrap around the planet reach hundreds of kilometers down into the atmosphere, NASA’s Juno spacecraft reveals, providing an unprecedented peek into the giant planet’s interior.
“Whatever’s making those colors and stripes still exists pretty far down,” planetary scientist Scott Bolton, head of the Juno mission, said October 19 at a meeting of the American Astronomical Society’s Division for Planetary Sciences. “That came as a surprise to many scientists.” Until now, researchers weren’t sure if Jupiter’s stripes were just blemishes atop the clouds or extended farther inward. The bands reach at least 350 to 400 kilometers beneath the cloud deck, Bolton reported in a news conference.
Juno arrived at Jupiter on July 4 and made its first up-close investigation of the planet on August 27. Coming within 5,000 kilometers of the cloud tops, Juno recorded the intensity of radio waves emanating from the planet. Different frequencies come from different depths; low frequencies originate from deep in the atmosphere while high frequencies originate higher up.
“Deep down, Jupiter is similar but also very different than what we see on the surface,” said Bolton, of the Southwest Research Institute in San Antonio. Some bands broaden while others vanish. “We can’t tell what all of it means yet, but it’s telling us hints about the deep dynamics and chemistry of Jupiter’s atmosphere.”