![]() ![]() Eruptions from Shishaldin have produced ash clouds in the past similar to those seen during the current eruption, most recently in January 2020. Satellite, seismic, and infrasound data is routinely monitored for signs of explosions that might produce ash clouds. Before the current activity, the 2019–2020 eruption of Shishaldin was the first to result in lava flows outside of the crater area since 1976. Minor eruptions in 20 erupted lava confined to the summit crater. Seismicity has remained at low levels and no infrasound signals of explosive activity have been detected.Įruptive activity could increase again rapidly with little or no warning. No significant ash emissions were observed in clear web camera images or satellite data, although mostly cloudy conditions obscured views of the volcano in the last few days. Ash deposits were focused to the south-southeast, downwind from the vent, and extended to the shore of Unimak Island.įollowing the July 18 episode, clear satellite images showed elevated surface temperatures consistent with low-level eruptive activity in the summit crater. These deposits generated mudflows that extended further down drainages on the volcano's flanks. High-resolution satellite images acquired after the activity on July 16 and July 18 showed pyroclastic deposits from the eruption extending as far as 1.9 miles (3 km) from the vent ( ). Incandescence was visible in clear web camera images, but no lava flow activity was observed outside of the summit crater ( ). ![]() Significant ash emissions on both days were preceded by around 6 hours of heightened eruptive activity, including elevated seismic tremor, infrasound signals, and increased surface temperatures visible in satellite images. The Aviation Color Code and Volcano Alert Level were raised to RED and WARNING for both episodes. Lower-level ash emissions continued for several hours but stayed below 10,000 ft. (7 km) above sea level ( ) and continued until 8:30 am AKDT (16:30 UTC). On July 18, ash emissions began around 7:00 am AKDT (15:00 UTC) initially reaching around 30,000 ft. (5 km) above sea level and extending for over 80 miles (125 km) south of the volcano. On July 15, ash emissions began at 9:50 pm AKDT (04:50 UTC on July 16) and continued until 11:30 pm (07:30 UTC on July 16) reaching 16,000 ft. Two significant episodes of elevated eruptive activity occurred at Shishaldin Volcano during the past week. Geological Survey Friday, July 21, 2023, 12:24 PM AKDT (Friday, July 21, 2023, 20:24 UTC) SHISHALDIN VOLCANO ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE U.S. ![]()
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |