Tuesday, 26 July 2016

Volcanos

Roundup of Global Volcanic Activity

Kliuchevskoi (Kamchatka): The volcano continues to erupt a lava flow that descends on the eastern flank. It also sometimes (such as during much of yesterday) has phases of near-continuous explosions at the summit craters, generating ash plumes that rise up to approx. 1 km from the summit. Today, no significant ash emissions were observed.

Sakurajima (Kyushu, Japan): After more than 3 weeks with no recorded eruption, a strong vulcanian-type explosion occurred this evening at 00:02 past midnight (15:02 UTC). The initial estimate of the ash plume was corrected from 10,000 to 20,000 ft (6 km) altitude, making the event one of the larger ones among Sakurajima's long list of vulcanian explosions throughout the past years. Whether or not the volcano will return to a more regular style of explosive activity remains to be seen.

Suwanose-jima (Ryukyu Islands): Judging from recent webcam imagery, activity has decreased again at the volcano although the On-take crater continues to produce a significant steam plume and occasional ash emissions, but much less vigorous than earlier this month. Only week glow if any can be seen at night.

Sinabung (Sumatra, Indonesia): Explosive activity continues. The most recent eruption was reported by PVMBG and VAAC Darwin yesterday at 10:28 local time. It generated an ash column that rose approx. 1500 m above the volcano's summit.

Popocatépetl (Central Mexico): The activity at the volcano has remained essentially unchanged and been rather low during the past week. On average, CENAPRED recorded 100-200 low-energy emissions ("exhalations") and few, generally weak explosions with ash emissions, accompanied by intermittent phases of weak tremor. Glow at the volcano's summit at night indicates the continued slow growth of a lava dome inside the inner crater.

Fuego (Guatemala): A small lava flow is descending on the upper SE flank into the Santa Teresa drainage, generating near-constant small glowing avalanches. Explosive strombolian activity is relatively week at the moment; the volcano observatory counted 20 explosions for the past 24 hours, generating ash plums that rose up to approx. 500 m and drifted 10-12 km S and SW before dissipating. Many of them were accompanied by shock waves and jet-engine like degassing sounds that lasted up to 2 minutes. Incandescent bombs were seen to reach to 150-200 m height above the crater.

Turrialba (Costa Rica): A series of eruptions has been occurring from the volcano's active western crater during the night and this morning and is likely still going on. Costa Rican volcanologist describe the explosions which each lasted a few minutes as phreatic, i.e. driven by overheated water from the hydrothermal system suddenly flashing into steam. The first explosions occurred at 21:22 and 22:16 local time last night and were followed by similar ones at 07:22 and 08:25 this morning. The eruptions were similar to many others in the ongoing phase of intermittent explosions at the volcano during the past months; they ejected ballistic blocks of high temperature to the crater rim and generated ash plumes that rose several hundreds of meters before drifting SW where ash fall occurred in nearby areas.

Nevado del Ruiz (Colombia): The Manizales volcano observatory reported a small ash emission yesterday afternoon, but cloud cover prevented detailed observations.

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