Yellowstone volcano: ‘Increased risk’ warning after scientists pinpoint ‘magma intrusion’ #Yellowstone #Magma #USA
YELLOWSTONE researchers have warned there is an “increased risk of hydrothermal explosion” at Steamboat Geyser after pinpointing a body of magma that “intruded” below Norris Geyser Basin years ago.
Scientists used GPS data to model what may have occurred below the surface to explain why an area near the basin has been inflating and deflating by several inches in erratic bursts for the past two decades. Their research, published in the Journal of Geophysical Research, revealed a body of magma had “intruded” beneath Norris in the Nineties. As the fluid got stuck and pressure built up, the ground would rise, and when the fluids were able to escape elsewhere, the ground deflated.
The paper, published in January, reads: “Recent activity has provided new insights into the causes of surface deformation in and around the Yellowstone Caldera, a topic that has been debated since the discovery of caldera floor uplift more than four decades ago.
“An episode of unusually rapid uplift centred near Norris Geyser Basin along the north caldera rim began in late 2013 and continued until an earthquake on March 30, 2014, thereafter, uplift abruptly switched to subsidence.
“Split at rates of several centimetres per year resumed in 2016 and continued at least through to the end of 2018.
“Modelling of GPS and interferometric synthetic aperture radar data suggests an evolving process of deep magma intrusion during 1996–2001.”
Today, the researchers believe magma-derived fluids could sit close to the surface, just a mile or so below the ground.
The study added: “The depth of shallow volatile accumulation appears to have shallowed from the 2014 to the 2016 deformation episode.
“Frequent eruptions of Steamboat Geyser since March 2018 are likely a surface manifestation of this ongoing process.
“Hydrothermal explosion features are prominent in the Norris Geyser Basin area, and the apparent shallow nature of the volatile accumulation implies an increased risk of hydrothermal explosions.”
Co-author Daniel Dzurisin told National Geographic on Friday: “In all likelihood, Norris has been a centre of deformation for a very long time.”
The new research does not indicate that the supervolcano is any closer to erupting.
Instead, these geologic movements may help explain why the park’s Steamboat Geyser, the world’s tallest active geyser, has been erupting at a record-breaking pace since March 2018.
While the threat of a supereruption remains a reality, the USGS has previously put minds at ease regarding “overdue” claims.
Yellowstone Volcano Observatory’s Scientists-in-Charge Jacob Lowenstern said in 2014: “When you see people claiming it’s overdue, usually the numbers they come up with say the last eruption was 640,000 years ago, but it erupts every 600,000 years.
“But, in fact, if you average the eruption intervals, there’s 2.1 million to 1.3 million and then another 640,000 years ago.
“If you average those numbers you come up with something that’s over 700,000 years.
“So, in reality, even if you tried to make this argument, it wouldn’t be overdue for another 70,000 years.”
Courtesy of express.co.uk
Yellow Alert issued due to unusual rapid inflation beneath Mt. Thorbjorn on Reykjanes peninsula, Iceland #YellowAlert #MountThorbjorn #reykjanes #iceland
The map shows recent earthquake activity in the area. Mt. Thorbjorn is situated just above the black triangle which indicates one of IMO’s seismographs.
Inflation has been detected in the last few days. An earthquake swarm has been ongoing during the same period. A state of uncertainty has been declared. The aviation color code has been raised to yellow for Reykjanes.
An inflation has been detected since January 21st and is centred just west of Mt. Thorbjorn on Reykjanes peninsula. The inflation is unusually rapid, around 3-4 mm per day and has accumulated to 2 cm to date. It has been detected both on continuous GPS stations and in InSAR images. The inflation is most likely a sign of magma accumulation at a depth of just a few km. If magma accumulation is causing the inflation, the accumulation is very small, with the first volume estimate is around 1 million cubic meters (0,001 km3). This is the conclusion of a meeting held with the Scientific council of the Civil Protection at the IMO this morning.
Accurate measurements of crustal deformation on Reykjanes peninsula span approx. three decades. During this period no comparable signal has been measured. This is unusual for this period. An earthquake swarm has been ongoing, since January 21st, alongside the deformation signal just east of the inflation centre (northeast of Grindavík). The largest earthquakes occurred on January 22nd and were of M3,7 and 3,6. They were felt widely on the Reykjanes peninsula and all the way to Borgarnes region. The earthquake swarm is currently in decline. Swarms like this are common and not unusual by itself in the area. The fact that an inflation is occurring alongside the earthquake swarm is a cause for concern and closer monitoring.
The inflation is centred within an active volcanic zone
The inflation is occurring on plate boundaries and within the volcanic system of Svartsengi which is either considered a separate system or part of the Reykjanes volcanic system. The last known eruption was during Reykjanes fires, which occurred between 1210-1240 AD. Within that period a several eruptions occurred within that system, thereof there were three eruptions in Svartsengi system. The eruptions were effusive (non-explosive) fissure eruptions erupting on 1-10 km long fissures. No explosive eruptions are known from this system. The largest eruption in the swarm, from 13th century, formed Arnarseturshraun lava (estimated 0,3 km3 and 20 km2). Historically, the duration of these eruptions spans from a few days up to several weeks. Seismic activity is very common in this area and is linked to the plate boundaries, geothermal activity and possible magma intrusions. The largest earthquakes measured in this area are about M5.5.
Courtesy of en.vedur.is
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