Volcanos

Roundup of Global Volcanic Activity – Continuing Activity for the week 20 July – 26 July 2022

Chiles-Cerro Negro – Colombia-Ecuador : Instituto Geofísico de la Escuela Politécnica Nacional (IGEPN) and the Observatorio Vulcanológico y Sismológico de Pasto del Servicio Geológico Colombiano (SGC OVSP) both monitor the Cerro Negro de Mayasquer and Chiles volcanoes, called the Chiles-Cerro Negro volcanic complex (CCNVC), and both issued reports on the seismic swarm that began on 27 May. This seismicity was mainly characterized by VT earthquakes, typically indicating rock fracturing events. The swarm continued during 12-26 July, though the number and size of events were variable. The earthquakes were located along a fracture zone on and as far as 3.5 km S of Chiles volcano, at depths less than 6 km. The number of long-period (LP) and very-long-period (VLP) earthquakes, low-energy events indicating fluid movement, had increased in the previous two weeks; 60 of such events were recorded on 17 July, the highest daily number of events recorded since the beginning of permanent monitoring in November 2013, and 64 were recorded in 20 July. During 12-23 July a total of 43 earthquakes had local magnitudes greater than 2; four of those events, a M 3.3 recorded at 1038 on 16 July, a M 2.8 at 0816 on 22 July, a M 3.5 at 1746 on 22 July, and a M 3 at 2247 on 23 July were all felt in surrounding areas, including in the municipality of Cumbbal, in the department of Nariño. At 0833 on 25 July a M 5.6 was recorded, with a hypocenter located about 10 km S of Tufiño (Carchi province, Ecuador). Building damage was reported in San Gabriel, Tulcán, and El Ángel (Ecuador) and in the Municipalities of Túquerres and Cumbal (Colombia). Data from continuous GPS geodetic bases located in the vicinity of the Chiles volcano showed a trend of inflation at a rate of approximately 28 mm/year that has been recorded since 2016 (the beginning of deformation monitoring) through the end of 2020, when the deformation stabilized. Neither inflation nor deflation was detected during the beginning of 2020 or in 2021. Inflation was again detected in March, at a rate of 32 mm/year. The rate of inflation notably increased during April-July to an average of 106 mm/year, occurring in at least two deformation zones, one S of Chiles and another in the Potrerillos caldera.

Dukono – Halmahera : PVMBG reported that during 19-25 July almost daily white-and-gray ash plumes from Dukono rose as high as 300 m above the summit and drifted N, E, and W.

Great Sitkin – Andreanof Islands (USA) : AVO reported that slow lava effusion at Great Sitkin continued during 19-26 July. Elevated surface temperatures were identified in satellite images during 19-20 July; weather clouds obscured satellite and webcam views during most of the rest of the week. Seismicity was low, and occasional local earthquakes were recorded. Steam emissions were visible in satellite images during 25-26 July.

Ibu – Halmahera : PVMBG reported that the eruption at Ibu continued during 21-25 July. Gray-and-white ash plumes of variable densities generally rose as high as 2 km above the summit and drifted in multiple directions.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported that a thermal anomaly over Karymsky was identified in satellite images during 14-21 July. Ash plumes were identified in satellite images drifting 170 km S and SE on 15 July.

Kilauea – Hawaiian Islands (USA) : HVO stated that by 19 July about 98 million cubic meters of lava had been erupted from a vent in the lower W wall of at Kilauea’s Halema`uma`u Crater since the current eruption began on 29 September 2021, raising the crater floor by 133 m. Lava continued to effuse from the vent during 19-26 July, entering the lava lake and flowing onto the crater floor. The lake level remained at the bounding levees, though lava oozed from the lake margins on most days. The sulfur dioxide emission rate was approximately 1,300 tons/day on 21 July.

Krakatau – Sunda Strait : The Darwin VAAC reported that during 20 and 22-24 July ash plumes from Anak Krakatau rose to 2.6-3 km (9,000-10,000 ft) a.s.l. and drifted SW, WSW, and W based on satellite and webcam images as well as weather models.

Lewotolok – Lembata Island : PVMBG reported that the eruption at Lewotolok continued during 20-26 July. Daily white or white-and-gray emissions rose as high as 500 m above the summit and drifted in multiple directions. Photos in some posted reports showed Strombolian activity at the active vent.

Merapi – Central Java : BPPTKG reported that the eruption at Merapi continued during 15-21 July. The heights and morphologies of the SW and central lava domes were unchanged from the previous week, and seismicity remained at high levels. As many as 22 lava avalanches traveled down the Bebeng drainage on the SW flank, reaching a maximum distance of 1.8 km.

Pavlof – Alaska Peninsula, Alaska : AVO reported that a minor eruption at a vent on Pavlof’s upper E flank was ongoing during 19-26 July. Seismic tremor persisted and multiple daily explosions were detected in seismic and infrasound data. Elevated surface temperatures were identified almost daily in satellite images; weather clouds sometimes prevented views. Diffuse ash emissions were visible in webcam images during 19-20 July. A low-level ash cloud that rose to 2.6 km (8,600 ft) a.s.l. was observed by a pilot at around 1150 on 22 July and corresponded to a slightly larger explosion detected in infrasound data. Steam emissions were visible in satellite images during 25-26 July.

Reventador – Ecuador : IG characterized the ongoing eruption at Reventador as moderate during 19-26 July. Gas-and-ash plumes, observed with the webcam or reported by the Washington VAAC, rose as high as 1.4 km above the summit and drifted in multiple directions. An active lava flow descending the NE flanks was visible in thermal webcam images during 21-24 July.

Sangay – Ecuador : IG reported a high level of activity at Sangay during 19-26 July. Daily ash-and-gas plumes were identified in IG webcam images and visible in satellite images according to the Washington VAAC. Plumes rose as high as 2 km above the volcano and drifted WNW, W, and S. Incandescent material was seen descending the SE flank during 21-22 July.

Semeru – Eastern Java : PVMBG reported that the eruption at Semeru continued during 19-26 July. At 1455 on 24 July an ash plume rose 300 m above the summit and drifted SW.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that the ongoing eruption at Sheveluch was characterized by explosions, hot avalanches, and lava-dome extrusion during 15-21 July. A daily thermal anomaly was identified in satellite images, and ash plumes were visible drifting 125 km E and SE during 16 and 18-19 July.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that the eruption at Suwanosejima’s Ontake Crater continued during 18-25 July. There were four explosions, producing eruption plumes that rose as high as 1.2 km above the crater rim and ejecting larger material 300 m from the vent. Crater incandescence was observed nightly, and volcanic tremor was occasionally recorded.

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