Reykjanes Peninsula Volcano – According to the latest report from IMO, the eruption on the Reykjanes peninsula seems to have come to a halt. The fissures that opened near the Sundhnúkagígar crater row on December 18th had stopped spewing lava by the morning of December 21st. The seismic activity had significantly decreased on December 19th and 20th, and by 5 PM on the 20th, lava was only erupting from two craters in the central part of the fissure.
The lava mainly flowed towards the east, although there was a flow towards the west near Stóra-Skógfell that had stopped advancing. As the night progressed into the early hours of December 21st, the eruptive activity declined further, and the seismicity continued to decrease. Scientists who conducted an overflight on the morning of December 21st confirmed that there was no visible eruptive activity, and the lava effusion at the craters had ceased.
However, some areas on the lava-flow field still emitted a faint glow, suggesting that lava might still be flowing through underground tubes. On December 22nd, at 2:59 PM, IMO downgraded the Aviation Color Code to Yellow, indicating that there were no active vents. In total, approximately 12 million cubic meters of lava had erupted, covering an area of about 3.4 square kilometers.
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The Grindavík, Sundhnúksgígar, and Svartsengi regions experienced ongoing seismic activity, which fluctuated on a daily basis but remained relatively low overall. Ground deformation data collected from GPS and satellite-based measurements revealed that magma was still accumulating beneath the Svartsengi region. As a result, a new hazard assessment was conducted, and an updated map was implemented on 22 December. The areas surrounding the fissure were downgraded from a very high risk to a high risk, while the assessment for Grindavík remained unchanged, still classified as “considerable.”
what is the oldest extinct volcano in the world
The city of Jackson, Mississippi is home to an intriguing geological feature known as Jackson Volcano. This extinct volcano lies 2,900 feet beneath the surface, hidden beneath the Mississippi Coliseum. The surrounding area, known as the Jackson Dome, is characterized by uplifted terrain and dense rock formations that can be easily detected through gravity measurements.
Back in 1860, geologist E.W. Hilgard proposed the existence of an anticline beneath Jackson based on his observations of surface strata. This theory further supported the presence of the volcano. Interestingly, the Jackson Dome contains a significant amount of pure carbon dioxide, which is utilized in oil production in the nearby Gulf Coast oil fields.
By analyzing noble gas data, scientists have determined that the Jackson Dome intrusion originated from the mantle approximately 70 million years ago. Throughout its history, the volcano experienced multiple uplifts, accompanied by the intrusion of dikes and the extrusion of volcanic material. This dynamic process also involved erosion and sedimentation, with evidence of a coral reef developing during a period of submergence.
During a later uplift, a considerable amount of oil at the crest of the dome transformed into vapor. However, in 1934, there were still over a hundred oil production wells in operation. This highlights the significance of the Jackson Dome in the oil industry.
It is believed that Jackson Volcano has been extinct for a staggering 66 million years. One hypothesis suggests that the volcano and the associated igneous activity in Mississippi were a result of the North America Plate passing over the Bermuda hotspot millions of years ago. Another possibility is that the volcanism was part of a global eruption triggered by superplumes, similar to the events that created the Deccan Traps and the Siberian Traps.
The story of Jackson Volcano and its geological history adds a fascinating dimension to the city of Jackson, Mississippi.