Phyus.org March 3, 2023 The effects of volcanic eruptions on the ionosphere have been well studied, however, evidence for the anticipated upper atmospheric neutral variations and their exact extents of change are rarely available. An international team of researchers (China, Germany, USA – MIT) found dramatic thermospheric disturbances following the 15 January 2022 Tonga eruption. The GRACE-FO and Swarm-C observations from the accelerometers exhibited three successive thermospheric density waves at ∼500 km altitudes propagating concentrically across the globe at 200–450 m/s phase speed and two of the three waves converged at the antipode of the epicenter. A large-scale and long-lasting […]
Category Archives: Volcanoes
Ice cores show even dormant volcanoes leak abundant sulfur into the atmosphere
Phys.org February 3, 2023 Sulfate aerosols are particles in the atmosphere that have a net cooling effect on the climate. One of the most uncertain aspects of climate modeling is the abundance of sulfate aerosols during the preindustrial era. Without knowing the amount of sulfate aerosols during the preindustrial times, it is difficult to estimate how much anthropogenic sulfate aerosols have offset warming from anthropogenic greenhouse gases. A team of researchers in the US (University of Washington, South Dakota State University, University of New Mexico, Michigan Technological University) examined preindustrial sulfate aerosols in a Greenland ice core. They found that […]
A year on, we now know why the Tongan eruption was so violent. It’s a wake-up call to watch other submarine volcanoes
Phys.org January 13, 2023 An international team of researchers (Tonga, New Zealand) studied the texture and chemistry of the erupted particles to find clues about the event’s violence. Isotopic “fingerprinting” showed at least three different magma sources were involved. Two magma bodies were older and resident in the middle of the Earth’s crust, the younger one joined shortly before the eruption. The mingling of magmas caused a strong reaction, driving water and other “volatile elements” out of solution and into gas. This created bubbles and an expanding magma foam, pushing the magma out vigorously at the onset of eruption. The […]
Signals from the ionosphere could improve tsunami forecasts
Phys.org December 12, 2022 Acoustic-gravity waves propagated by the eruption and tsunami caused global complex ionospheric disturbances. Researchers at the University of Washington studied the nature of the perturbations from Global Navigation Satellite System observables over the southwestern Pacific. After processing data from 818 ground stations, they detected supersonic acoustic waves, Lamb waves, and tsunamis, with filtered magnitudes between 1 and 7 Total Electron Content units. Phase arrivals appeared super positioned up to ∼1,000 km from HTHH and were distinct by ∼2,200 km. Within ∼2,200 km, signals had an initial low-frequency pulse that transitioned to higher frequencies. They found the […]
The Yellowstone Supervolcano Holds Way More Liquid Magma Than We Realized
Science Alert December 8, 2022 An obvious but key requirement for an eruption is the presence of magma. This magma also needs to be distributed so that it can mobilize and erupt as a coherent body. A key issue for eruption hazard assessment is to ascertain how much magma is below the surface and where. Researchers at UC Davis modeled seismic data to image melt beneath the Yellowstone Caldera. They concluded that more melt is present than had been recognized, and it is located at shallow depths in the crust. But the melt fraction they estimated is substantially lower than […]
Monitoring ‘frothy’ magma gases could help evade disaster
Phys.org November 21, 2022 Researchers in Japan repeatedly measured isotopic compositions of noble gases and CO2 in volcanic gases sampled at six fumaroles around the Kusatsu-Shirane volcano (Japan) between 2014 and 2021 to detect variations reflecting recent volcanic activity. The synchronous increases in 3He/4He at some fumaroles suggested an increase in magmatic gas supply since 2018. The increase in magmatic gas supply was also supported by the temporal variations in 3He/CO2 ratios and carbon isotopic ratios of CO2. The 3He/40Ar* ratios showed significant increases in the period of high 3He/4He ratios. The temporal variation in 3He/40Ar* ratios may reflect changes […]
The Tonga Eruption’s 50 Million Tons of Water Vapor May Warm Earth For Months to Come
Scince Alert September 25, 2022 Recently, researchers calculated that the eruption of Hunga Tonga-Hunga Ha’apa spewed a staggering 50 million tons of water vapor into the atmosphere, in addition to enormous quantities of ash and volcanic gases. Particles of rock and ash can also temporarily cool the planet by blocking sunlight. Widespread and violent volcanic activity in Earth’s distant past may have contributed to global climate change, triggering mass extinctions millions of years ago. In underwater volcanoes, submarine eruptions can draw large parts of their explosive energy from the interaction of water and hot magma, which propels huge quantities of […]
Tonga is home to 170 islands. A new one just formed from an underwater volcanic eruption
Phys.org September 27, 2022 The Pacific nation of Tonga is made up of 170 islands, but it just welcomed its newest addition—thanks to an underwater volcano. Near the center of the nation’s island formation lies the Home Reef volcano in the South Pacific. On Sept. 10, the volcano began to erupt for the first known time since 2006, oozing lava and ejecting plumes of steam and ash in and above water, according to NASA’s Earth Observatory. Just 11 hours after the eruption began, a new island had appeared, and NASA confirmed its formation with satellite images. When the island was […]
Elusive atmospheric wave detected during Tonga volcanic eruption
Phys.org September 19, 2022 Using state-of-the-art observational data and computer simulations an international team of researchers (Japan, USA -University of Hawaii) discovered the existence of Pekeris waves—fluctuations in air pressure that were theorized in 1937 but never proven to occur in nature, till after the Tonga eruption. The atmospheric wave pattern close to the eruption was quite complicated, but thousands of miles away the disturbances were led by an isolated wave front traveling horizontally at more than 650 miles per hour as it spread outward. The air pressure perturbations associated with the initial wave front were seen clearly on thousands […]
The World Is Not Ready For The Next Super-Eruption, Scientists Warn
Science Alert September 6, 2022 According to researchers in the UK over the next century, large-scale volcanic eruptions are hundreds of times more likely to occur than are asteroid and comet impacts, put together. The peril posed by volcanoes may also be greater. In a 2021 study based on data from ancient ice cores, researchers found the intervals between catastrophic eruptions are hundreds or even thousands of years shorter than previously believed. The history of many volcanoes remains murky, making it hard to anticipate future eruptions and focus resources where risks are highest. According to the researchers we need more […]