Volcanos

Roundup of Global Volcanic Activity – New Activity for the Week 22 January 2020 – 28 January 2020

Fernandina | Ecuador : A reported from IG on 23 January noted that seismicity increased after the approximately nine-hour long 12 January eruption at Fernandina, characterized by sporadic earthquakes with magnitudes greater than 3 and small swarms. The strongest earthquake was a M 4.2 recorded on 21 January. Most of the earthquakes were shallow though occasionally some were located at depths greater than 10 km. Deformation of about 35 cm was detected around the fissures that produced the lava flows. The lava flows emitted on 12 January covered an approximate area of 3.8 square kilometers; no new thermal anomalies nor gas emissions have been recorded since the eruption.

Kuchinoerabujima | Ryukyu Islands (Japan) : Very small eruptive events recorded at Kuchinoerabujima on 20, 23, and 24 January produced grayish-white plumes that rose 500 m above the crater rim. Ashfall 2 km NE of the crater was confirmed during aerial observations on 23 January. The number of volcanic earthquakes increased during 25-26 January. An eruptive event was recorded at 0148 on 27 January, though weather clouds prevented visual confirmation; volcanic tremor, changes in tilt data, and infrasound signals accompanied the event. Sulfur dioxide gas emissions were 200-1,000 tons per day during 20-27 January; JMA characterized emissions of 600-1,000 tons per day as high.

Reykjanes | Iceland : IMO reported possible magma accumulation beneath Reykjanes, centered along the plate boundary below the Svartsengi fissure system, just W of Thorbjorn. Deformation began on 21 January and was unusually rapid, with the rate of inflation occurring at 3-4 mm per day (3 cm total by 29 January), as detected by InSAR and continuous GPS data. Magma accumulation, if that was causing the inflation, was small with an estimate volume of 1 million cubic meters, at 3-5 km depth. Deformation on the Reykjanes peninsula had been measured for three decades with no previously comparable signals. An earthquake swarm accompanied the deformation, just E of the center of the inflation. The largest earthquakes were M 3.6 and 3.7, recorded on 22 January, and felt widely on the Reykjanes peninsula and all the way to Borgarnes region. Earthquake swarms are relatively common, though coupled with deformation caused IMO to raise the Aviation Code to Yellow on 26 January. The swarm was declining by 26 January. On 29 January IMO stated that data showed continuing uplift and the earthquake swarm was ongoing.

Taal | Luzon (Philippines) : PHIVOLCS reported that white steam-laden plumes rose as high as 800 m above Taal’s main vent during 22-28 January and drifted SW and NE; ash emissions ceased around 0500 on 22 January. Remobilized ash drifted SW on 22 January due to strong low winds, affecting the towns of Lemery (16 km SW) and Agoncillo, and rose as high as 5.8 km (19,000 ft) a.s.l. as reported by pilots. PHIVOLCS stated that since the 12-13 January phreatomagmatic eruption activity has generally weakened. Both the number and magnitude of volcanic earthquakes declined; by 21 January hybrid earthquakes had ceased and both the number and magnitude of low-frequency events had diminished. GPS data had recorded a sudden widening of Taal Caldera by ~1 m, uplift of the NW sector by ~20 cm, and subsidence of the SW part of Volcano Island by ~1 m just after the main eruption phase. The rate of the deformation patterns was smaller during 15-22 January, and generally corroborated by field observations; Taal Lake had receded about 30 cm by 25 January but about 2.5 m of lakewater recession (due to uplift) was observed around the SW portion of the lake, near the Pansipit River Valley where ground cracking had been reported. The Alert Level was lowered to 3 (on a scale of 0-5) on 26 January and PHIVOLCS recommended no entry onto Volcano Island and Taal Lake, nor into towns W of the island within a 7-km radius. Sulfur dioxide emissions were low at 140 tonnes per day on 22 January but averaged around 250 tonnes per day through 26 January; emissions were 87 tonnes per day on 27 January and below detectable limits the next day. According to the Disaster Response Operations Monitoring and Information Center (DROMIC) there were a total of 125,178 people in 497 evacuation centers as of 2020 on 28 January.

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