Roundup of Global Volcanic Activity:
Etna (Sicily, Italy): At the surface, Etna remains calm. The current seismic signal and tremor values at the moment don’t suggest a new paroxysm from the New SE crater is be expected very soon (although some paroxysms have shown build-up phases of less than a few hours only). Interestingly, two weak earthquake swarms have occurred two days ago under the flanks of the volcano at opposite sides of the mountain: the first, weaker one, was at depths around 25 km under Monte Spagnolo on the NW flank, the second occurred shortly after at depths around 15 km under the area of Milo on the SE flank. The largest quake was a magnitude 2 event.
Santorini (Cyclades, Greece): Seismic activity has showed a small increase again: a small swarm of earthquakes has occurred just east of the island at depths between 6 and 15 km. The “largest” quake (not felt) was a small magnitude 2.4 event at 12.5 km depth yesterday. For now, this small swarm probably means nothing unusual.
El Hierro (Canary Islands, Spain): IGN places the earthquake that just occurred also at magnitude 4.9, but at the “usual” 20 km depth and in the “usual” area about 10 km west of the island. So far, this has been the strongest quakes during the whole crisis! A (for El Hierro) powerful earthquake has just occurred; EMSC places it at magnitude 4.9 and depth at 10 km with a location off to the north of the island. These data are preliminary. IGN’s more detailed earthquake information might correct this.
Long Valley (California): Some felt earthquakes have occurred recently along the southern boundary of Long Valley Caldera, the latest a 3.8 magnitude quakes yesterday. This is not unusual for the volcanic system and does not mean any volcanic eruption should be expected in a near future. The alert status remains green (normal).
Popocatépetl (Central Mexico): After the period of increased emissions (sometimes near continuous small to moderate explosions) and seismic activity during 28-29 March, the volcano has calmed down again to levels similar to before. During yesterday, the rate of emissions dropped to 1-2 per hour again, and ash plumes and explosions were significantly smaller.
Santa María / Santiaguito (Guatemala): Activity has remained weak. Only few small explosions occurred from the dome and the block lava flows on the flanks of the dome showed little movement recently, in the form of small avalanches from their steep fronts. Light ash fall occurred in the areas of Finca San José and Finca La Quina.
Pacaya (Guatemala): Weak strombolian activity continues, accompanied by white-bluish degassing (SO2). So far, no new lava flow has appeared.
Fuego (Guatemala): Activity has remained stable, with occasional strombolian explosions ejecting glowing lava bombs to about 100 m height above the crater. Ash plumes rose 600-800 m and drifted about 10 km into southerly directions. Weak avalanches of blocks were observed rolling down towards the Ceniza and Taniluyá canyons.
Telica (Nicaragua): The earthquake swarm still continues, accompanied by near continuous tremor, although at reduced intensity.
Masaya (Nicaragua): Periods of elevated volcanic tremor continue to appear regularly at the volcano. At the moment, seismic activity is again relatively calm.
Reventador (Ecuador): IG observed a steam column rising 700 m yesterday and glow at night from the summit, indicating that weak effusive activity continues there. Seismic activity remains elevated with fluctuating intensity, dominated by signals corresponding to internal fluid movements.
Tungurahua (Ecuador): Seismic activity, including volcanic-tectonic and long period earthquakes have increased in number and magnitudes during the past 2 days, suggesting new magma might have started to rise within the volcano and could herald a new phase of explosive activity soon. As of yesterday (IG’s latest report), no particular surface activity (such as explosions, ash venting) has been observed.