Honolulu, Hawaii 2021-05-08 14:49:48 –
Volcano Watch is a weekly update of articles and activities written by scientists and affiliates of the US Geological Survey Hawaiian Volcano Observatory.
May 3rd is three years after the devastating eruption of Kilauea’s Lower East Rift Zone. In 2018, the rise in the water level of the summit lava lake caused by the rise in magma pressure culminated in a large eruption on the lower flank, after which the summit lava lake suddenly drained and the crater began to collapse. Did.
Surprisingly, in 2018, almost the same series of events took place on another Pacific island. Ambrym, an active volcano in the South Pacific country of Vanuatu, experienced similar historical changes in 2018 as Kilauea volcano.
Prior to 2018, there were five lava lakes on the summit caldera of Ambrym volcano. A few weeks before the eruption, at least one of the lava lakes showed a significant rise, similar to what happened before Kilauea’s 2018 eruption.
The quake began on the summit of December 14, and soon magma invaded along the southeastern rift zone of Ambrym, causing extensive cracks. Within two days, an ash eruption rose from the summit, draining all five lakes and causing the craters to collapse inward.
On December 17, magma movement stopped. Shortly thereafter, residents observed pumice drifting ashore, indicating that a submarine eruption had occurred far below the rift zone. At the summit, one of the collapsed crater lava lakes was soon replaced by a water lake.
The cracks on Ambrym caused damage to the building in 2018, but if it happened on land, the eruption could have been more dangerous. In 1913, a similar pattern of activity occurred on Ambrym, causing a land-based eruption that destroyed the hospital.
A newly published study of the 2018 Ambrym eruption, written by an international team of scientists, shows that rising lake levels before the eruption are putting pressure on the magma chambers at the summit. It emphasizes that it is likely to be.
The authors state that this pattern is documented in detail in Kilauea with a broader surveillance network. In essence, the lava lake at the top is a giant pressure gauge of the magma chamber below, similar to a liquid barometer.
Analysis of lava chemistry showed that the Ambrym magma dyke intersected an isolated pocket around the old magma on the route along the rift zone. This mix of old and new magma also occurred during the 2018 eruption of Kilauea’s lower east rift zone, affecting eruption rates and hazards.
Observations of Ambrym and Kilauea volcano suggest that the rapidly rising mountaintop lava lake may be a common precursor to future lateral eruptions. In summary, the eruptions of Kilauea and Ambrym have some important lessons for risk prediction.
This process affects the dangers at yet another volcano known for lava lake activity. Mount Nyiragongo in the Democratic Republic of the Congo has a large peak lava lake that has been active intermittently for decades.
The lake’s water level rose prior to the massive 1977 and 2002 eruptions of Mt. Nyiragongo. The 1977 eruption created an unusually fast lava flow, killing dozens of people. The lava flow from the 2002 eruption covered much of the city of Sesame, leaving 120,000 homeless and evacuating more.
Today, Lake Nyiragongo has risen to about the same high levels as before the 1977 and 2002 eruptions. Another recent study by another international team of scientists predicts that this could lead to a new dimension of eruption within a few years.
Kilauea’s current lava lake, which began to form in December 2020, is fundamentally different from the lakes that existed before 2018. Today’s lakes are lava passively accumulating at the bottom of the Halemaumau crater, which is not the case. It is directly above the conduit that rises from the magma chamber. This means that changes in lava levels cannot be used as pressure gauges in the same way.
Over the years, the Kilauea, Ambrym, and Nyiragongo communities have been devastated by eruptions supplied by magma spilling from the summit. Our hope is to gain a better understanding of the eruptions and their precursors in these aspects and use that knowledge to mitigate risk and improve future expectations.
Update of volcanic activity
Kilauea volcano is erupting. Its USGS volcanic alert level is WATCH (https://www.usgs.gov/natural-hazards/volcano-hazards/about-alert-levels). The latest information on Kilauea is published daily.
The activity of lava is limited to Halemaumau, and lava erupts from the vent on the northwest side of the crater. Laser rangefinder measurements on April 29 this morning show that the western (active) part of the lake has a lava depth of 227 m (744 ft) and that the eastern part of the lava lake has solidified on the surface. I will. The summit inclinometer has recorded small changes in the last 24 hours. The sulfur dioxide emission rate measured on April 25 was 375 tonnes / day. Seismic activity remains stable and tremors increase. For the latest information on eruptions, see https://www.usgs.gov/volcanoes/kilauea/current-eruption.
Mauna Loa has not erupted and remains a volcanic alert level recommendation. This alert level does not mean that the eruption is imminent or that the progress from the current level of anxiety to the eruption is certain. The latest information on Mauna Loa is published weekly.
Last week, a small magnitude earthquake of about 150 was recorded under Mauna Loa. Most of these occurred below peaks and highlands at depths less than 8 km (about 5 miles). Global Positioning System (GPS) measurements have continued to show slightly elongated peak deformation patterns over the past week. Gas concentrations and fumarole temperatures at both the summit and the sulfur cones of the southwestern rift zone remain stable. The webcam shows no change in the landscape. For more information on current surveillance of Mauna Loa volcano, see: https://www.usgs.gov/volcanoes/mauna-loa/monitoring..
Last week there were two events in the Hawaiian Islands, including three or more felt reports. At 6:18 on April 26, there was a M3.4 earthquake 30 km (18 miles) southwest of Hawaii Ocean View and 42 km (26 miles) deep. AM HST and M2.8 earthquake 13 km (8 mi) south of Honokaa, 31 km (19 mi) deep, April 26, 2:09 HST.
HVO continues to closely monitor for signs of increased activity in both Kilauea’s ongoing eruption and Mauna Loa.
Visit the HVO website for past volcano watch articles, the latest information on Kilauea and Mauna Loa, volcano photos, maps, and recent earthquake information.Email your question [email protected]
Volcano Watch: The Rise and Fall of Lava Lakes Source link Volcano Watch: The Rise and Fall of Lava Lakes