Asosan volcano (Kyushu, Japan) - Smithsonian / USGS Weekly Volcanic Activity Report for 13 April-19 April 2022 (Continuing Activity)
JMA reported that no eruptions had been recorded at Asosan after the end of the last eruption in October 2021. Crater incandescence, which had been occasionally visible since December 2021, was absent beginning on 27 February. Deflation began around 27 February but stabilized in April.
Wed, 20 Apr 2022, 19:0719:07 PM | BY: VN
Observations of the crater from 17 March revealed that it had deepened, compared to pre-eruption conditions, and that water had returned. Sulfur dioxide emissions had increased to 1,600 tons per day on 25 March, but four observations made during 29 March-12 April showed values in the range of 800-1,200 tons per day. Though these values were higher than those measured in September 2021, before the eruption, they represented a decreasing trend.
During a field visit on 7 April scientists observed white emissions rising from Nakadake Crater and gray pools of hot water on the crater floor. A hot spring was active on the S side of the pools. The area of the water represented about 40 percent of the crater floor and the water temperature was 71 degrees Celsius.
JMA lowered the Alert Level to 1 (on a scale of 1-5) on 15 April, noting that the likelihood of an eruption affecting an area within a radius of 1 km had decreased.
Source: Japan Meteorological Agency (JMA)
From: Global Volcanism Program, 2022. Report on Asosan. In: Mayberry, G (ed.), Weekly Volcanic Activity Report 13 April-19 April 2022. Smithsonian Institution and US Geological Survey.
Thu, 17 Mar 2022, 09:52
Asosan volcano (Kyushu, Japan) - Smithsonian / USGS Weekly Volcanic Activity Report for 9 March-15 March 2022 (New Activity / Unrest)
JMA reported that the amplitude of volcanic tremor signals at Asosan had decreased at around 1540 on 27 February and remained low. White plumes rose 600-800 m above the crater during 7-14 March. During field surveys conducted on 8 and 10 March sulfur dioxide gas emissions were 1,300 and 900 tons per day, respectively; these values were higher than those measured before the October 2021 eruption. ... Read all
Thu, 3 Mar 2022, 00:49
Asosan volcano (Kyushu, Japan) - Smithsonian / USGS Weekly Volcanic Activity Report for 23 February-1 March 2022 (New Activity / Unrest)
JMA reported that the amplitude of volcanic tremor signals at Asosan increased at around 0500 on 24 February and then increased again around 0900. About 45 minutes later JMA raised the Alert Level to 3 (on a scale of 1-5) and warned the public to stay at least 2 km away from the crater. Tremor amplitude decreased at around 1540 on 27 February. ... Read all