Volcanos

Roundup of Global Volcanic Activity - New Activity for the week of 26 April - 2 May 2023

Ambae - Vanuatu : On 27 April the Vanuatu Meteorology and Geo-Hazards Department (VMGD) reported that the cone in Ambae’s Lake Voui continued to produce emissions consisting of steam, volcanic gases, and ash. Volcanic earthquakes were recorded by the seismic network. Activity intensified during 5-7 April and was characterized by higher steam, gas, and ash plumes and nighttime incandescence from the growing cone. Lava flows from the vent traveled N into a small water lake, filling it in.

Barren Island - Andaman Islands (India) : The Darwin VAAC reported that continuous ash plumes from Barren Island were identified in satellite images during 0620-1250 on 1 May rising to 4.6 km (15,000 ft) a.s.l. and drifting NW.

Bezymianny - Central Kamchatka (Russia) : KVERT reported that the ongoing eruption at Bezymianny was characterized by gas-and-steam emissions, occasional collapses at the lava dome, and hot avalanches during 20-27 April. A daily thermal anomaly was identified in satellite images.

Kanlaon - Philippines : PHIVOLCS issued a special notice for Kanlaon at 0700 on 1 May, noting increased sulfur dioxide emissions. Real-time, continuous volcanic gas monitoring of thermal springs on the N flank detected sulfur dioxide for the first time beginning in April. On 30 April a Flyspec instrument measured an average of 1,099 tonnes per day of sulfur dioxide emissions at the summit crater, a value which was significantly higher than the average of 124 tonnes per day measured since March. During the month of April, the seismic network recorded 141 volcanic earthquakes, an average of five per day, at shallow depths less than 10 km in the N and W parts of the volcano. Ground deformation data from continuous GPS and electronic tilt data indicated short-term inflation of the lower and mid-flanks of the volcano since March.

Rincon de la Vieja - Costa Rica : OVSICORI-UNA reported that phreatic eruptions continued to periodically occur at Rincón de la Vieja during 26 April-1 May. Near-continuous and intense tremor continued along with a few low-frequency, tornillo-type earthquakes and volcanic-tectonic earthquakes. Phreatic events at 0453, 0523, and 0545 on 26 April generated gas-and-steam plumes, and an event at 0528 on 27 April produced a gas-and-steam plume that rose 800 m above the crater rim. Several phreatic events occurred during 27-28 April and generated gas-and-steam emissions that generally rose no higher than 200 m above the crater rim. A small event at 1030 on 30 April produced a gas-and-steam plume that rose 500 m. A gas-and-steam plume from a moderate phreatic eruption at 1306 on 1 May rose 1 km above the crater rim and was seen by residents N of the volcano and in images from webcams located in Sensoria and Gavilan. A small event was recorded later that day at 2032. Field observations found that the larger eruption on 21 April ejected tephra up to 3 km around the crater, mainly to the N and S. An analysis of ash deposits under a microscope revealed gray and dark metallic, sulfur-rich spheres characteristic of the hydrothermal system as well as juvenile volcanic glass. Ballistics up to 15 cm in diameter were found around the crater.

Sheveluch - Central Kamchatka (Russia) : KVERT reported that the ongoing eruption at Sheveluch was generally characterized by occasional explosions, continuing lava-dome growth, incandescence, and strong fumarolic activity during 20-27 April. Gas-and-steam emissions obscured the volcano during 20-23 April. A thermal anomaly was identified in satellite images during 24-27 April. A photograph taken on 29 April by the Kamchatka Volcanological Station showed a lava dome which was higher than the crater rim.