Volcanos

Roundup of Global Volcanic Activity – New Activity for the week 20 April – 26 April 2022

Edgecumbe – Southeastern Alaska (USA) : AVO stated that a seismic swarm beneath Kruzof Island near Edgecumbe that began at about 0200 on 11 April had declined to background levels by 22 April. The swarm prompted an in-depth analysis of satellite data which spanned the last 7.5 years. The data showed that a broad area of uplift, about 17 km in diameter, was located about 2.5 km E of Edgecumbe. The uplift began in August 2018 and deformed at a rate of up to 8.7 cm per year in the center of the area, totaling 27 cm of uplift; the deformation was ongoing. Retrospective analysis of seismic data revealed that earthquakes started occurring in 2020, though the recent swarm was unusual. The deformation and seismic data together suggested magma movement beneath the volcano, consistent with an intrusion at about 5 km below sea level.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported that a thermal anomaly over Karymsky was visible in satellite images during 15-22 April. Explosions during 17-19 and 21 April generated ash plumes that rose as high as 7.5 km (24,600 ft) a.s.l. and drifted 500 km NE. SE, and E. A powerful explosion at 0805 on 20 April (local time) generated ash plumes that rose as high as 11 km (36,100 ft) a.s.l. and drifted more than 2,000 km NE. Ashfall was reported in the territory of the Kronotsky Reserve (Semyachinsky, Valley of Geysers), 50 km NE, and at Cape Nalychevo, 100 km S. Explosions continued through the day; ash plumes rising to 5 km (16,400 ft) a.s.l. were visible in satellite images at 1500, local time. The previous ash plume was about 505 x 130 km and drifted NE, S, and SE at an altitude of 8.7 km (28,500 ft) a.s.l.

Krakatau – Sunda Strait : PVMBG reported that the eruption at Anak Krakatau had intensified. Dense white, gray, and black ash plumes rose as high as 1 km above the summit and drifted SW during 17-19 April. Strombolian activity was first observed on 17 April; that same day that sulfur dioxide emissions increased to 181.1 tons per days from 28.4-68.4 tons per day recorded during 14-15 April. A dense gray-black ash plume rose around 800 m above the summit at 0621 on 21 April and drifted E. At 0049, 0145, 0237, and 1730 on 22 April dense gray-to-black ash plumes rose 500-1,500 m above the summit and drifted SW. Incandescent material was occasionally ejected above the vent. Sulfur dioxide emissions notably increased to 9,219 tons per day on 23 April. That same day, at around 1219, lava flowed into the sea and produced a white steam plume at the entry point. Ash plumes were taller on 23 April, rising to 3 km above the summit at 0608, 1200, and 2020, with SSW, S, and SE drifts. The plumes continued to be characterized as dense, and white, gray, and black in color.

Purace – Colombia : Observatorio Vulcanológico y Sismológico de Popayán, Servicio Geologico Colombiano (SGC), reported that during 19-25 April the number and magnitudes of earthquakes at Puracé was similar to the previous week. Signals included 72 volcano-tectonic (VT) events, indicating rock fracturing, along with 207 long-period (LP) events and 14 low-energy tremor pulses, indicating fluid movement. Data from the GNSS (Global Navigation Satellite System) geodetic network continued to show inflation on the centimeter scale. Sulfur dioxide emissions were lower than the previous week, with values of 937-992 tonnes per day, and gas plumes drifted NW. During a field visit on 22 April scientists observed no changes to the crack near Puracé and Curiquinga volcanoes, and no visible gas emissions. Additional cracks, oriented NW-SE, were observed, in addition to volcanic ash deposits that were likely emplaced on 29 March.

Ruapehu – North Island (New Zealand) : On 26 April GeoNet reported that elevated unrest at Ruapehu had been ongoing for the past five weeks, characterized by lake water heating, volcanic gas output, and strong volcanic tremor. Tremor levels fluctuated the past week but represented a record for the longest and strongest tremor episode ever recorded at the volcano. The lake water temperature remained at 37 degrees Celsius, indicating a substantial amount of heat from magma at a shallow depth (0.5-2 km), though water chemistry showed no change based on sampling during 31 March-15 April.

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