Yogyakarta - The activity of Mount Merapi on the border of Central Java and the Special Region of Yogyakarta (DIY) continues to increase. The Center for Geological Disaster Research and Technology Development (BPPTKG) recorded an average of 400 internal earthquakes in Merapi.
Head of BPPTKG Hanik Humaida explained that the seismicity in Merapi in November was much higher than in October.
Based on BPPTKG data, this month the Merapi earthquake recorded 1,069 times shallow volcanic earthquakes (VTB), 9,201 times multi-phase earthquakes (MP), 29 times low frequency (LF) earthquakes, 1,687 times earthquake avalanches (RF), 1,783 times gusts ( DG) and 39 tectonic earthquakes (TT).
"The intensity of the seismicity this month (November) was 2-5 times higher than last October," Hanik was quoted as saying in the official BPPTKG statement, Monday (30/11/2020).
Hanik explained that during the November period, avalanches were observed from Mount Merapi Observation Post (PGM) Babadan, Magelang.
"Avalanches were observed with a maximum sliding distance of 3 km in the west sector towards the upstream of Kali Sat on November 8 at 12.57 WIB," he explained.
Furthermore, Hanik explained the morphological analysis of the peak area based on photos from the southeast sector this month. As a result, there was a change in morphology around the peak, namely the collapse of part of the 1954 Lava dome.
"Meanwhile, based on the analysis of drone photos on November 16, 2020, a change in the morphology of the crater wall was observed due to the collapse of the old lava, especially Lava1997 (south), Lava1998, Lava1888 (west) and Lava1954 (north). .
He also conducted gas monitoring from the VOGAMOS station (Volcanic Gas Monitoring System) in Lava 1953 showing the value of CO2 gas (ppm) at intervals of approximately 3 hours for data collection. He explained that during the beginning of this month to November 20, the CO2 concentration showed a fairly constant value, namely an average of 525 ppm. But then it has increased.
"After this period until the end of this month, it shows an increase to a maximum value of 675 ppm," he explained.
Meanwhile, for the deformation of Merapi, Hanik explained that the shortening rate monitored using electronic distance measurement (EDM) this month is 11 cm per day.
Monitoring the activities of Merapi also by monitoring the visuals directly. He explained that in the November period, thick white smoke was observed coming out of the peak of Merapi.
"The smoke is white, thin to thick with weak to moderate pressure. The maximum smoke height of 750 m was observed from PGM Babadan on November 26, 2020 at 05.50 WIB," he said.
Based on these data, Hanik concluded that there was an increase in the volcanic activity of Merapi. The monitoring data, he continued, shows the process of magma pushing towards the surface.
"There is an increase in the volcanic activity of Merapi in the form of an internal seismic activity which reaches 400 times per day, the deformation rate reaches 11 cm per day, the concentration of CO2 gas has increased to 675 ppm, and changes in peak morphology due to the intensive shedding activity," he said.
Hanik explained, based on the high level of monitoring data, the activity status was determined in the Alert activity level (Level III). The current potential hazards are in the form of lava avalanches, eruption of volcanic material in the event of an explosive eruption and hot clouds up to a maximum of 5 kilometers away.
