Volcanos

Roundup of Global Volcanic Activity - New Activity for the week of 28 December-3 January 2017

Katla (Southern Iceland): An increased number of earthquakes has been occurred at shallow depths (few km) under the SW part of the ice-covered volcano's caldera. The largest event was a near-surface magnitude 3.5 event 3.9 km ESE of Goðabunga at 07:09 local time this morning. Whether the quakes are volcanic in origin (a swarm caused by magma intrusion) or caused by adjustments of the glacier's weight (or likely both) is unknown. Katla has been on elevated alert since Oct 2016 when an intense seismic swarm occurred that triggered fears the volcano might erupt again soon (its last eruption dating back to 1918 and it is thought to be statistically "overdue"). The seismic swarm in Sep / Oct 2016 had been the largest in recent decades. It began on 29 Sep 2016, increased on 30 Sep with several quakes of magnitudes of 3 and higher, and lasted until early October.

Bezymianny | Central Kamchatka (Russia) : KVERT reported strong gas-and-steam emissions at Bezymianny during 23-30 December and a daily thermal anomaly over the volcano. The Aviation Colour Code remained at Orange.

Cayambe | Ecuador : On 28 December IG reported continued anomalous seismic activity at Cayambe characterized by volcano-tectonic and long-period earthquakes located 2-8 km below the summit. As many as 40 earthquakes had been recorded each day for the previous two weeks and starting on 24 December that number again increased, especially for volcano-tectonic events. A swarm on 27 December consisted of 100 small-magnitude events. A strong sulphur odour persisted, and cracks in the glacier near the summit that climbers has recently reported were visible during an overflight. In addition, deformation on the flanks was detected in GPS data.

Ebeko | Paramushir Island (Russia) : KVERT reported that, according to observers in Severo-Kurilsk (Paramushir Island) about 7 km E, explosions at Ebeko produced ash plumes during 24-27 December that rose to an altitude of 2.5 km (8,200 ft) a.s.l. Minor ashfall was noted in Severo-Kurilsk on 23 and 26 December. The Aviation Colour Code remained at Orange (the second highest level on a four-colour scale).

Klyuchevskoy | Central Kamchatka (Russia) : Based on satellite and webcam images KVERT reported that explosions at Klyuchevskoy recorded on 1 January generated ash plumes that rose to an altitude of 5 km (16,400 ft) a.s.l. and drifted 114 km SE. The Aviation Colour Code was raised to Orange (the second highest level on a four-colour scale).

Sabancaya | Peru : On 28 December the Technical and Scientific Committee for volcanic risk management of the Arequipa region (comprised of five groups including IGP's OVS and INGEMMET's OVI) recommended that the Alert Level for Sabancaya be raised from Yellow to Orange based on increased activity detected during 8 November-26 December. A progressive increase in the number of explosions per day to 52 was noted along with the detection of 14 daily hybrid events. Harmonic tremor was recorded on 21, 24, and 25 December. Thermal anomalies were identified by the MIROVA system with the last one being recorded on 24 December. Gas-and-ash plumes rose as high as 4.5 km above the crater and drifted 40 km in different directions, affecting the villages of Maca, Achoma, Yanque, and Chivay, and areas to the W and NW including Huambo, Cabanaconde, Pinchollo, Lari, Tapay, and Madrigal. The public was warned to stay at least 12 km away from the volcano. An explosion on 2 January 2017 generated an ash plume that rose 2.5 km and drifted more than 30 km S and SW.