Roundup of Global Volcanic Activity – New Activity for the week of 1 February-7 February 2017
Chirinkotan | Kuril Islands (Russia) : On 6 February SVERT noted that the Aviation Colour Code for Chirinkotan had been lowered to Green (lowest level on a four-colour scale).
Cleveland | Chuginadak Island (USA) : On 3 February AVO reported that recent satellite data indicated that a new lava dome had been extruded, and partially filled Cleveland’s summit crater. The new dome is about 70 m in diameter, similar in size to previous lava domes that have developed on the crater floor. Since explosive activity has sometimes followed lava-dome extrusion, AVO increased the Aviation Color Code to Orange and the Volcano Alert Level to Watch. Weakly elevated surface temperatures were identified in several satellite images during 6-7 February, consistent with the presence of a lava dome that began forming in late January.
Takawangha | Andreanof Islands (USA) : On 3 February AVO stated that the seismic swarm that began at Takawangha on 23 January continued but at a decreased rate and intensity. The rate of earthquakes peaked at 190 events on 24 January, and since then had steadily declined; 2-8 events per day were recorded from late January to 3 February. Most of the events were located 7-8 km ESE, at shallow depths. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.
Piton de la Fournaise | Reunion Island (France) : OVPF reported that seismicity and inflation at Piton de la Fournaise significantly increased on 2 January. Based on seismic data, an eruption began at 1940 on 31 January. Visual observations on 1 February confirmed that the active vent was located about 1 km SE of Château Fort and about 2.5 km ENE of Piton de Bert. Lava fountains rose 20-50 m above the 10-m-high vent, and ‘a’a lava flows branched and traveled 750 m. Two other cracks had opened at the beginning of the eruption but were no longer active. Tremor levels decreased in the early hours of the eruption; RSAM values then fluctuated at mid-range, and lava-fountain heights were variable (between 20-50 m). On 2 February two lava fountains at the vent were visible, and lava flows had traveled an additional 500 m E. The vent was 128 m long and about 35 m high at the highest part. The next day RSAM levels were more stable, at a value which was half of what it was at the beginning of the eruption. On 4 February OVPF noted that significant fluctuations of volcanic tremor were detected for more than 24 hours, with intensity levels reaching those observed at the onset of the eruption. Higher levels of seismicity continued through 7 February. Poor weather conditions prevented visual observations during 4-7 February.