Phys.org August 19, 2024 Transitions in eruptive style during volcanic eruptions strongly depend on how easily gas and magma decouple during ascent. Stronger gas-melt coupling favors highly explosive eruptions, whereas weaker coupling promotes lava fountaining and lava flows. The mechanisms producing these transitions are still poorly understood because of a lack of direct observations of bubble dynamics under natural magmatic conditions. An international team of researchers (UK, Italy, France) combined x-ray radiography with a high-pressure/high-temperature apparatus to observe and quantify in real-time bubble growth and coalescence in basaltic magmas from 100 megapascals to surface. For low-viscosity magmas, bubbles coalesced and […]
Category Archives: Volcanoes
New study disputes Hunga Tonga volcano’s role in 2023–24 global warm-up
Phys.org July 26, 2024 The Hunga Tonga-Hunga Ha’apai (Hunga) submarine volcanic eruption on 15 January 2022 produced aerosol and water vapor plumes in the stratosphere. An international team of researchers (Canada, USA – industry, Texas A&M) calculated the climate forcing for the 2 years after the 15 January 2022, Hunga Tonga-Hunga Ha’apai (Hunga) eruption using satellite observations of stratospheric aerosols, trace gases and temperatures to compute the tropopause radiative flux changes relative to climatology. The net downward radiative flux decreased compared to climatology. The Hunga stratospheric water vapor anomaly initially increased the downward infrared radiative flux, but this forcing diminished […]
Tonga’s volcanic eruption could cause unusual weather for the rest of the decade, new study shows
Phys.org May 30, 2024 The amount of water vapor injected into the stratosphere after the eruption of Hunga Tonga-Hunga Ha’apai (HTHH) was unprecedented, and it is therefore unclear what it might mean for surface climate. Researchers in Australia used chemistry climate model simulations to assess the long-term surface impacts of stratospheric water vapor (SWV) anomalies similar to those caused by HTHH, but neglected the relatively minor aerosol loading from the eruption. The simulations showed that the SWV anomalies led to strong and persistent warming of Northern Hemisphere landmasses in boreal winter, and austral winter cooling over Australia, years after eruption, […]
Earth scientists describe a new kind of volcanic eruption
Science Daily May 27, 2024 Explosive volcanic eruptions driven by magmatic fragmentation or steam expansion produce hazardous atmospheric plumes composed of tephra particles, hot gas, and entrained air. However, an eruption mechanism outside this phreatic–magmatic spectrum was suggested by a sequence of 12 explosive eruptions in May 2018 at Kīlauea, Hawaii, that occurred during the early stages of caldera collapse and produced atmospheric plumes reaching 8 km above the vent. A team of researchers in the US (US Geological Survey Volcano Science Center California Volcano Observatory, University of Oregon, USGS Portland, USGS Vancouver, WA) used seismic inversions for reservoir pressure as […]
Glaciers could provide powerful new volcano monitoring tool
Phys.org September 12, 2023 An international team of researchers (UK, Italy, Germany, USA – University of Alaska, Cornell University) studied 600 glaciers located on and near 37 ice-clad volcanoes in South America. The results demonstrated glacier sensitivity to volcanic heat. They distinguished between “volcanic glaciers” and “proximal glaciers” and calculated their equilibrium line altitudes (ELAs). For each ice-clad volcano, they compared the ELAs of its volcanic glaciers to those of its proximal glaciers and established volcanic thermal anomaly. Results highlighted the impact of volcanic heat on glacier elevation; emphasized the need to exclude glaciers on, or near, volcanoes from glacier-climate […]
Tonga volcano unleashed fastest ever undersea flows: study
Phys.org September 7, 2023 In December 2021, an undersea volcano in the southern Pacific Ocean, the Hunga Tonga–Hunga Ha‘apai (Hunga volcano) began erupting. In January 2022 the eruption reached a powerful climax, triggering atmospheric waves that traveled around the globe and a tsunami that swept across the Pacific Ocean. An estimated 75% of Earth’s volcanoes are underwater, and 20% of all fatalities caused by volcanic eruptions since 1600 CE have been associated with underwater volcanism. Yet, explosive underwater eruptions are poorly understood. An international team of researchers (UK, New Zealand, Kingdom of Tonga, Australia, USA – industry) reported that volcanic […]
Three easily measurable parameters can provide valuable information about the structure of volcanoes
Phys.org August 31, 2023 Volcanoes exhibit a wide range of eruptive and geochemical behavior, which has significant implications for their associated risk. The suggested first-order drivers of intervolcanic diversity invoke a combination of crustal and mantle processes. To better constrain mantle-crustal-volcanic coupling, an international team of researchers (Ireland, Switzerland) used the Lesser Antilles to show that melt flux from the mantle, identified by proxy in the form of boron isotopes in melt inclusions, correlates with the long-term volcanic productivity, the volcanic edifice height, and the geophysically defined along-arc crustal structure. These features were the consequence of a variable melt flux […]
The Tonga volcano eruption caused a ‘super bubble’ in Earth’s ionosphere, disrupting satellite navigation
Phys.org May 30, 2023 The Hunga Tonga Volcano eruption launched waves which generated traveling ionospheric disturbances (TIDs) in the ionosphere, which are known to adversely impact radio applications such as Global Navigation Satellite Systems (GNSS). One such GNSS application is Precise Point Positioning (PPP), which can achieve cm-level accuracy using a single receiver, following a typical convergence time of 30 min to 1 hr. An international team of researchers (Australia, USA – Boston College, Vietnam) used a network of ionosondes located throughout the Australian region in combination with GNSS receivers to explore the impacts of the volcano eruption on the […]
Researchers reveal disturbances of Tonga volcanic eruption
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 […]
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 […]