Gas and ash emissions were observed at the Reventador, between 600 and 1,200 meters above crater level, in a northeast, northwest and southeast direction, confirmed by VAAC Washington No thermal alerts have been recorded in the last 24 hours.
Explosions were observed, as well as incandescence in the crater and rolling boulders up to 500 meters below the summit on the southern flank. In addition, the descent of a pyroclastic flow was observed up to 400 meters below the summit, on the southwest flank on May 4, 2021 at 6:10 am local / 11:10 am UTC.
The Fagradalsfjall eruption continues through a main crater. The active crater is at the fifth fissure opening on April 13. His activity changed around midnight on May 2, and has since shown pulsating behavior. These pulses have intermittent active periods of 8 to 12 minutes, with 1 to 2 minutes of rest periods in between. Active pulses begin with strong fountain activity, with fountains reaching up to 100-150m above the ground, and some even higher. In view of these changes in activity, the size of the risk area at the eruption site is being re-evaluated.
Discreet bursts of gas from periodic lava fountains in Geldingadalir can be seen in an image from the NASA Aqua / MODIS satellite on May 4. Downwind, they merge into a plume extending ~ 500 km from Iceland based on Sentinel-5P Tropomi SO2 data.
Gas puffs, related to pulsatile activity at the Geldingadalur eruptive site, and plume over 500 km to the southwest - NASA Aqua / MODIS satellite image
The lava flow last week (April 26 - May 3) averaged 7.5 m3 / s. This is a slightly higher number than the number obtained last week compared to the previous week. So there is no sign that the rash is giving way. The volume of eruptions has now reached 23 million cubic meters, and the lava area is 1.41 km2. The biggest change last week is in the depression between Stórahrút and the humps east of Geldingadalur and in the lava spit from Geldingadalur to Meradalur.
Sources: IMO, RUV, Univ. Iceland, webcam langihryggur N, Ragnar Heiðar Þrastarson.
Eruption at Fagradalsfjall / Krisuvik - thermal anomalies at 05.05.2021 / 03:10 (slightly lower) - Doc. Mirova _MODIS_Latest10NTI
A microlight flight carried out on May 4 in the morning by a team from the Piton de La Fournaise observatory confirmed that the two cones were still active; projections of lava were only visible this morning at the smallest cone downstream, while a lake of lava was still present at the level of the most imposing cone upstream.
The flow of the lava at the exit of the eruptive vents, is done mainly in tunnels and this almost to the upper limit of the large slopes, where resurgences of lava are visible on the surface. The flow front continues its slow progression at the top of the Grandes Pentes. In 24 hours, the flow front progressed by around 180 m, and this morning was around 1,500 m altitude. As observed during the last two days, fires in the vegetation located at the foot of the rampart and at the flow front were observed.
The CO2 fluxes in the soil are still increasing in the far field (Plains region) The slight inflation (swelling) of the summit zone and the base of the terminal cone is confirmed.
Source: OVPF press release 04.05.2021
Piton de La Fournaise - the 2 active cones and degassing on the lava tunnel flows - photo OVPF 04.05.2021 / 09h loc - 05h UT
Piton de La Fournaise - the 2 active cones, with their "lava lake" - more degassing at the downstream cone - photo OVPF 04.05.2021 / 09h loc