Volcanos

Roundup of Global Volcanic Activity

Askja (Central Iceland): A large landslide occurred from the southern wall of the Askja caldera yesterday night. The slide caused a large flood wave in the Öskjuvatn lake that also swept into the famous Viti crater. There are no reports of victims. Although there have been speculations that the slide could have been triggered by magmatic processes, it is most likely a result of summer warming, melting frozen soil in the caldera walls, destabilizing it.

Zhupanovsky (Kamchatka, Russia): Several small ash emissions occurred at the volcano during 16-21 July. The resulting plumes dissipated quickly. Aviation color code is at orange.

Aso (Kyushu): Activity remains elevated at Asosan volcano. Although no new ash emissions were reported recently, the Nakadake crater shows intense degassing and bright glow from hot fumaroles is visible at night. It seems that the crater lake which usually occupied the bottom of the crater has evaporated.

Semeru (East Java, Indonesia): Activity, weak during the past months, seems to have picked up. A new lava flow has started to slowly descend the southeastern slope. Since the intense explosive phase of activity in February 2012, accompanied by pyroclastic flows down the southern slope, a lava dome has been growing slowly inside the breached summit crater. This dome now started to form a more or less coherent lava lobe that began descending through the notch onto the upper southern slope. Weak glow is visible at night.

Shishaldin (United States, Aleutian Islands): According to the Alaska Volcano Observatory, weak activity continues. MODIS data show elevated surface temperatures in the summit crater, but there are no visual or other indicators of eruptive activity available.

Semisopochnoi (United States, Aleutian Islands): Earthquakes have decreased but are still above background levels. No eruptive activity has been recorded. Alert level remains yellow.

Santiaguito (Guatemala): No explosions were observed since yesterday, but the lava flow at the eastern rim of the Caliente dome remains active, producing rockfalls into the Nima 1 river canyon. Strong degassing is occurring from the dome.

Fuego (Guatemala): No significant changes in activity have occurred at the volcano. The observatory reported 8 weak and one moderate strombolian-type explosion since yesterday. Ash plumes rose up to 800 m above the crater, and produced avalanches of glowing material on the upper slope. No lava flow was active.

San Miguel (El Salvador): The volcano continues to produce important gas emissions as well as occasional small ash explosions. Tremor remains at very high levels (20 times above normal), caused by internal fluid movements. The likelihood of new eruptive activity in the near to medium future remains elevated.

Cerro Negro de Mayasquer (Colombia): Seismic unrest continues at the volcanic massif of Chiles and Cerro Negro. However, it decreased during the past week with less than 700 events recorded, compared to 1500-1800 per week during the month before. Most earthquakes were associated with internal rock fracturing and located at shallow 1-7 km depth in an area 4 km SW of the Chiles dome. Magnitudes reached 2.7 and some quakes were felt. Slight deformation has been detected at the Chiles dome as well.

Reventador (Ecuador): Intermittent small explosions continue as well as slow lava extrusion at the summit, evidenced by thermal hot spots visible on satellite data.

Ubinas (Peru): The volcano has been relatively calm over the past days, producing mostly a very weak gas plume with dilute ash, as well as sporadic small explosions.