Further measurements were made at Fagradalsfjall / Reykjanes Peninsula on Monday July 19, when the plane equipped with an Isavia radar altimeter took profile measurements of the lava. In addition, data from the Pléiades satellite of July 2 has been received. Terrestrial models have been made based on these measurements and they are compared to data from June 26.
Eruption at Fagradalsfjall - parameters of the eruption on 19.07.2021 - Doc. Jarðvisindastofnun Háskólans
The average lava flow over the period from June 26 to July 2 (6 days) was a little over 10 m³ / s but from July 2 to 19 (17 days) the average flow was 7.5 m³ / s.
Volcanic activity changed at the end of June. Then the activity began to fluctuate between periods of strong lava flow, interspersed with periods of calm. Current measurements show that the lava flow has diminished considerably. The rash is therefore clearly on the decline.
The lava volume is now 96 million cubic meters, and the area of the lava field is just under 4 square kilometers. The increase in area has been very small over the past three weeks, as lava has mainly accumulated in the Meradalir valleys and on the western slope of these. During the past two weeks, no lava has flowed in Geldingadalur, Nátthaga and Syðri Meradalir.
2021.07.21 Fagradalsfjamm - thermal anomalies in Meradalur - image Sentinel-2 bands 12,11,4 from 21.07.2021 - one click to enlarge
Over the past three weeks the flow has decreased, indicating that the pressure in the system is now decreasing. However, it is too early to try to predict how long the rash will last.
Source : http://jardvis.hi.is/eldgos_i_fagradalsfjalli, mbls, Hraun.vedur
Fagradalsfjall - Meradalur - Iceland Volcano Timelapses
Merapi activity report July 16-22, 2021
This week, lava avalanches were observed 62 times in the southeast with a maximum slide distance of 1,200 m, 101 times in the southwest with a maximum slide distance of 1,800 m, 2 times in the west with a maximum sliding distance of 1,500 m, and once to the north-west with a glide of 500 m.
Avalanches observed on the west side are old lava from 1992 and 1998, and avalanches leading to the northwest are old lava from 1948.
Morphological analysis of the Tunggularum Camera Station shows that the volume of the dome in the southwest sector is 1,880,000 m³. While the analysis of the Deles3 Camera Station shows the volume of the central dome of 2,808,000 m³.
The deformation of Mount Merapi, which was monitored using EDM this week, showed a distance shortening rate of 7cm / day.
The volcanic activity of Mount Merapi is still quite high in the form of effusive eruption activity. The state of the activity is defined in level 3 / siaga.
The current potential danger consists of lava avalanches and hot clouds in the southeast-southwest sector for a maximum of 3 km to the Woro River, and 5 km to the Gendol, Kuning, Boyong rivers. , Bedog, Krasak, Bebeng and Putih.
The ejection of volcanic material in the event of an explosive eruption can reach a radius of 3 km from the summit.
A satellite radar image from last night on July 22 at 9:32 p.m. (July 23 05:32 UTC) shows a small area of uplift about 50 m (~ 150 ft) in diameter at the center of Great Sitkin crater suggesting a magma rise near the surface. This lava dome-like feature appears to have been in place between July 14-22. As a result, AVO is increasing the Aviation Color Code to Orange and the Volcanic Alert Level to Watch.
Seismicity has been at relatively low levels this week compared to last week and we suspect the lava dome feature was put in place last week. Moderately high surface temperatures consistent with this feature were observed in satellite data on July 22. Cloudy conditions have obscured satellite views of the volcano for most of the past week. AVO will continue to closely monitor this new uplift feature.
The prognosis for eruptive activity is uncertain. Continued growth of the Lava Dome characteristic, additional explosive events, or a return to non-eruptive behaviors are all possible. The AVO will report significant changes and observations in the surveillance data if they occur.
The Semisopochnoi was downgraded from the Aviation Orange color code to YELLOW on 07/21/2021 at 4:28 p.m.
Seismicity is greater than background noise, but no evidence of explosive activity was detected in the seismic or infrasound data. No activity was observed in the cloudy satellite views, but strong vapor emission from the active vent was observed on the web camera images from the night of July 22.
This summer's fieldwork restored remote access to Semisopochnoi's cameras and seismic stations on the island, which is useful for keeping tabs on one of the most remote active volcanoes in Alaska in the far west of the Aleutian Islands.
The Semisopochnoi aviation code remains in YELLOW, and the volcanic alert in Advisory.