Thursday 21 September 2017

Volcanos

Roundup of Global Volcanic Activity - New Activity for the week of 13 September-19 September 2017

Agung | Bali (Indonesia) : Increased seismicity at Agung, as well as the severity of past eruptions, prompted PVMBG to raise the Alert Level to 2 (on a scale of 1-4). The report noted that volcanic earthquakes (VA) began to be recorded on 10 August and shallow volcanic earthquakes (VB) began to be recorded on 24 August. Local tectonic earthquakes were also recorded and began to increase consistently on 26 August. PVMBG warned the public to stay at least 3 km away from the crater. On 13 September a climber observed a sulfatara plume rising from the bottom of the crater as high as 50 m above the crater rim. During 14-18 September four earthquakes centered around Agung were felt. On 18 September PVMBG reported that the number of VA and VB events continued to increase; the Alert Level was increased to 3. The exclusion zone was increased to 6 km, with an additional expansion to 7.5 km in the N, SE, and SSW directions. Elevations above 950 m were also restricted.

Dieng Volcanic Complex | Central Java (Indonesia) : PVMBG reported that during 8 July-14 September measurements indicated an increase in water temperature at Sileri Crater lake (Dieng Volcanic Complex) from 90.7 to 93.5 degrees Celsius. Soil temperatures also increased, from 58.6 to 69.4 degrees Celsius. At Timbang Crater temperatures in the lake increased from 57.3 to 62.7, and in the soil they decreased from 18.6 to 17.2. The report noted that conditions at Timbang Crater were normal. Temperature increases at Sileri, along with tremor detected during 13-14 September, prompted PVMBG to raise the Alert Level to 2 (on a scale of 1-4). PVMBG warned the public to stay at least 1 km away from the crater rim, and for residents living within that radius to evacuate.

Zhupanovsky | Eastern Kamchatka (Russia) : Based on visual observations, KVERT reported that on 17 September explosions at Zhupanovsky generated gas-and-steam plumes with small amounts of ash that rose to altitudes of 6-7 km (19,700-23,000 ft) a.s.l. and drifted 20 km SW. The Aviation colour Code was raised from Green to Orange, the second highest level on a 4-colour scale. About 30 minutes later satellite images showed ash plumes drifting 10 km E. Later that day gas-and-steam plumes rose 4 km (13,100 ft) a.s.l. The Aviation colour Code was lowered to Yellow, and then on 20 September it was lowered to Green.

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