Soputan Volcano Eruption December 16, 2018

Soputan Volcano is a Stratovolcano located in South Minahasa Regency and Southeast Minahasa Regency, North Sulawesi Province. The peak height of G. Soputan is around 1784 m above sea level. The growth of the lava dome at Soputan Peak has been observed since 1991, spilling out the lip of the crater causing frequent lava avalanches, with a sliding distance of about 2 to 6.5 km from the peak to the west (the farthest), east and north. The closest residential areas are at a distance of about 8-10 km from the summit. During the rainy season there can be formation of steam from rainwater by lava domes that are still hot and can trigger secondary eruptions, namely in the form of phreatic eruptions (steam eruptions) that can trigger avalanches of lava domes and pyroclastics flows. In the camping area on the northeast slope, about 3 to 4 km from the top of G. Soputan, it has the potential to be hit by heavy ash rain and potentially hit by sand, gravel and rock (incandescent). The eruption of gunung Soputan is mainly on the western – southeast slope, when heavy rains occur it can result in lahars leading to: S. Ranowangko, S. Lawian, S. Popang, Londola Kelewehu and Londola Katayan. Other potential hazards are lava avalanches which still often occur around volcanic bodies, generally occurring in the north and east. But what you have to watch out for is, if there is a lava dome avalanche which is followed by hot clouds falling (pyroclastic flow) to the west (Silian), because the crater openings go to this area. The potential for eruption of G. Soputan can be volcanic ash which can have an impact on flight safety.

Activity Level

Changes in the status of G. Soputan starting from May 6, 2014 to the present are as follows:

  1. On May 6, 2014 the level of activity was increased from Level II (Alert) to Level III (Standby) at 11:00 WITA.
  2. On August 7, 2014 the level of activity was lowered from Level III (Standby) to Level II (Alert) at 12.00 WITA.
  3. On December 26, 2014 the level of activity was increased from Level II (Alert) to Level III (Standby) at 03:00 WITA.
  4. On July 3, 2015 the level of activity was lowered from Level III (Standby) to Level II (Alert) at 16.30 WITA.
  5. On January 4, 2016 the level of activity was increased from Level II (Alert) to Level III (Standby) at 18:00 WITA.
  6. On April 21, 2016 the level of activity was lowered from Level III (Standby) to Level II (Alert) at 12.00 WITA
  7. On October 3, 2018, the level of activity is increased from Level II (Alert) to Level III (Standby) at 01.00 WITA

Volcano Monitoring

Soputan is currently monitored with a monitoring network of 4 Seismic Stations and 1 Tiltmeter Station. There were 5 volcano observers placed in the Soputan Volcano Observers Post. In the level III activity level (Standby) routine reports are carried out every 6 hours every day.

Conclusion

Until now, the status of Gunung Soputan is still at Level III (Alert) with the recommendation of the danger zone, which is a radius of 4 km and sectoral expansion to the southwest-west as far as 6.5 km. People around G. Soputan are encouraged to prepare mouth and nose protective masks to avoid the potential danger of volcanic ash for the respiratory system. The people living around the banks of the rivers which are upstream in Soputan have to be aware of the potential threat of lahar, especially in the rainy season.

Chronology of Eruption

Monitoring data of Mount Soputan from the period of August to the beginning of October 2018 showed a significant increase in the volcanic activity. On October 3, 2016 at 01:00 WITA the activity level of G. Soputan was increased from Level II (Alert) to Level III (Alert). The eruption period of G. Soputan then occurred on October 3-4, 2018. After that the seismic activity of G. Soputan tended to decrease. On Saturday, December 15, 2018 starting at 5:00 p.m. WITA the seismic data indicated a rapid and significant increase. An increase in seismicity continues to occur and finally on Sunday 16 December 2018 at 1:02 a.m. the earthquake erupted with a maximum amplitude of 40 mm (overscale) with a duration of 598 seconds, accompanied by thunderous sounds that were heard with weak-moderate intensity from the Soputan Volcano Observation Post located in Silian Raya (about 10 km southwest of G. Soputan). The height of the eruption column is not observed because it is covered in fog. On Sunday, December 16, 2018 at around 3:09 a.m., the ray of fire above the peak of G. Soputan was observed and the height of the eruption column was ± 3,000 m above the peak (± 4,809 m above sea level) with columns of gray and thick intensity leaning towards southeast. At 05:40 WITA the eruption column was ± 7,000 m above the peak (± 8,809 m above sea level) with a column of gray and thick intensity ash leaning to the southeast. Up to 08:00 WITA, VONA has been published twice on December 16, 2018 at 04:00 WITA with ORANGE color code and at 5:54 WITA with RED color code. Until now, continuous tremors continue to be recorded with the maximum amplitude (overscale) indicating that the eruption activity is still ongoing.


Soputan Volcano Eruption (North Sulawesi) October 3, 2018

After the status was increased on October 3, 2018 at 01:00 WITA, the eruption episodes of Soputan Volcano began on the same day at 8:47 WITA. The eruption has an ash column height reaching around 4000 m above the peak (around 5800 meters above sea level) and recorded on a seismogram with a maximum amplitude of 39 mm with a duration of about 6 minutes. The spread of dominant volcanic ash towards to the west – north west.

After the eruption occurs, the seismic amplitude (RSAM – Realtime Seismic Amplitude Measurement) that reflects the energy of the magmatic activity of Soputan Volcano continues to increase. The eruption then occurred again, until 12:00 WITA a subsequent 3 (three) eruptions were observed, namely at 10:44 WITA with the ash column height observed around 2000 meters above the peak (about 3800 meters above sea level), at 11:12 WITA with the ash column height observed around 2500 meters above the peak (around 4300 meters above sea level) and at 11:52 WITA with the ash column height observed around 5000 meters above the peak (around 6800 meters above sea level).

Since  yesterday until now VONA has been sent 5 times in stages from YELLOW (since 2 October 2018 at 18:46 WITA) then to ORANGE (3 October 2018 at 09:09 WITA, 11:10 WITA and 11:59 WITA ) and finally changed to RED on October 3, 2018 at 12:18 WITA.

Now, PVMBG (Center of Volcanology and Geological Disaster Mitigation) seismic stations installed in several locations around  Soputan Volcano still continue to record seismicity which is dominated by continuous tremors with varying amplitude exceeding the overscale limit. Satellite thermal anomaly data shows a significant increase in temperature at the peak of Soputan Volcano with Volcanic Radiative Power (VRP) reaching 186 MW.

The results of the latest Soputan Volcano monitoring data analysis indicate that Soputan Volcano’s magmatic activity is still high and has the potential to erupt both explosively in the form of vertical ash columns and effusively in the form of lava flows and hot clouds. Until October 3, 2018 at 12:00 WITA it can be concluded that the activity status of Soputan Volcano is still at Level III (Standby) with the estimated danger zone recommendations in all areas within a 4 km radius of the peak and sectoral expansion as far as 6.5 km from the peak to the West – Southwest. The citizen around Soputan Volcano is recommended to prepare a mask to anticipate the potential danger of respiratory tract disruption from the possibility of ash rain.


Increased Status of Soputan Volcano, North Sulawesi on October 3, 2018 at 01:00 WITA

Soputan Volcano is a Strato volcano located in a geographical position 1 deg 06 min 30 sec North Latitude and 124 deg 44 min East Longitude. Located in South Minahasa Regency and Southeast Minahasa Regency, North Sulawesi Province. The altitude of Soputan Volcano is around 1784 m above sea level. The volcanic activity of  Soputan Volcano on the surface is characterized by gas flow and the growth of lava domes. This lava dome is often followed by lava flows towards the West-Southwest, North and East. Historically, the eruption of Soputan Volcano can be explosive in the form of vertical or effusive ash eruptions in the form of lava flows and hot clouds.

MONITORING AND ANALYSIS RESULTS

Visual and instrumental monitoring can be interpreted as follows:

  1. Visual monitoring with thermal cameras at night shows the presence of hot images at the top of Soputan Volcano which indicate high temperature lava.
  2. Volcanic seismicity began to increase in September 2018 from around 2 earthquakes/day to 101 earthquakes/day on October 2, 2018. At the same Interval time, blowing activities experienced an increase from around 2-6 times/day to 851 times/day on October 2, 2018.
  3. The activity of lava drops has increased slowly from mid-July 2018 to the end of August 2018 from around 3 times/day to around 16 times/day. However, from September 2018 to October 2, 2018, the number of lava drops experienced a more significant increase from around 16 times/day to 193 incidents per day.
  4. Seismic amplitude (RSAM – Realtime Seismic Amplitude Measurement) shows the acceleration (acceleration) trend especially starting on October 2, 2018 at around 16:00 WITA.

ACTIVITIES LEVEL AND RECOMMENDATIONS

The results of monitoring data analysis indicate that the potential for eruption of Soputan Volcano has increased. Therefore, to anticipate the potential for eruption, from October 3, 2018 at 01:00 WITA, the status of Soputan Volcano activities is increased from Level II (Alert) to Level III (Alert) with the following recommendations:

  1. The Citizen to not have activity in all areas within a radius of 4 km from the peak of Soputan Volcano and in the area of sectoral expansion to the West-Southwest as far as 6.5 km from the peak which is the crater opening area to avoid the potential threat of lava and hot clouds.
  2. The Citizen around Soputan Volcano is recommended to prepare a mask to anticipate the potential danger of respiratory tract disruption in the event of ash rain.
  3. The Citizen to be aware of the potential threat of lava flows that can occur after an eruption, which is where the eruption material is carried away by water, especially in rivers that head around the slopes of Soputan Volcano, such as Ranowangko River, Lawian River, Popang River and Londola Kelewahu River.
  4. The Citizen around Soputan Volcano is expected to be calm, not provoked by the issues of the eruption of Soputan Volcano. The Center for Volcanology and Geological Disaster Mitigation always cooperates with BNPB, North Sulawesi Provincial Government (Regional Disaster Management Agency), Minahasa District Government, South Minahasa and Southeast Minahasa about Soputan Volcano activities. Citizen must follow directions from the Regional Disaster Management Agency.
  5. The Regional Government must always coordinate with the Observation Station of Soputan Volcano in Silian Tiga, Silian Raya District, Southeast Minahasa Regency, North Sulawesi Province or with the Center for Volcanology and Geological Disaster Mitigation in Bandung.
  6. MAGMA Indonesia can be accessed through the website https://magma.vsi.esdm.go.id or through the MAGMA Indonesia Android application which can be downloaded on Google Play. Community participation is also highly expected by reporting incidents related to Soputan Volcano activities through the Disaster Report feature. Stakeholders in the aviation sector can access the VONA (Volcano Observatory Notice for Aviation) feature.

Preparedness efforts have been and continue to be carried out by PVMBG through regular coordination with relevant stakeholders (Local Government, BPBD, airports and other related parties) so that strategic steps can be taken by various parties in accordance with their respective duties. Early warning for aviation safety has been carried out with VONA shipment with Yellow color code on 2 October 2018 at 17:46 WITA.

Source: Center for Volcanology and Geological Disaster Mitigation, Geological Agency, Ministry of Energy and Mineral Resources


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