AMLAPURA – Volcanic activity of Gunung Agung in the past week continues to decline.
The intensity of seismicity and magma movement tends to decrease, while deformation (bloat) shows a stationary pattern. But the status of Mount Agung is still Level III (Standby).
This was conveyed by Head of Sub Division of East Indonesia’s Disaster Mitigation PVMBG, Devy Kamil Syahbana, while explaining summaries of Gunung Agung activity for one week, Saturday (18/11).
Based on the monitoring results of PVMBG, seismicity in Gunung Agung since November 12, 2017 to November 19, 2017 has decreased.
Some very shallow seismicities such as low frequencies and recorded gusts in the last one week period, but with an insignificant number.
A spasmodic tremor earthquake is still recorded indicating the presence of magmatic fluid flow from depth, but the number is still not significant.
For deformation (changes in the shape of a mountain / bloat), it tends to show a stationary pattern.
Not to be seen again the significant deformation patterns of inflation or deflation that was previously observed clearly in the period August-October 2017.
Through satellite monitoring, thermal energy can still be observed on the surface of the crater, but still has not undergone significant changes. The satellite on November 14 recorded a slight widening in one of the smoke exit holes at this time (at coordinates – 8.3436, 115.5093).
Water temperature measurement results in the spring around Gunung Agung also have not shown any significant changes.
While visually, the smoke that went out in the crater of the past week was observed to reach a height of 700 m. Previously the average range of 50-200 meters.
According to Devy, this can be due to two things. First the internal factors, along with the emergence of low frequency earthquakes and gusts manifest the flow of hot fluid from the magma to the surface that is still going on. Second, external factors such as rain can affect the thickness / height of observed smoke.
“Smoke occurs because there is warming by the magma vapor to the surface,” said Devy, yesterday.
PVMBG concluded, the movement of magma in the body of Mount Agung is still visually observed and recorded instrumental. But the intensity tends to decline in the past week.
Does this tendency of activity allow the status of Gunung Agung back to Level II (Alert)? Devy has not dared to make sure. All depends on the activity of Mount Agung. Status changes, he said, can not be scheduled.
“The status of Gunung Agung is currently at Level III (Standby) but the status continues to be evaluated every day carefully and may change according to the level of activity and threat of volcanic eruption Agung volcano,” he explained. Added, related status changes will be viewed based on the stability of the trend of the overall observation data.
“Before the 8th (November) then the quake had consistently declined, but the trend changed because there is a magnitude 5. Earthquake We wait until the downward trend is observed again if it will decrease (status), so even when it will raise, the rising trend must be observed too, so just look forward, it all depends on the mountain, “he explained.
Meanwhile, unmanned drone teams or drones from Aero Terrascan Bandung again flown to search data about the gas released by the crater of Mount Agung.
Drone flight was held at Selat Square, Village / Sub District Selat, Karangasem, Saturday at 07.00 Wita.
Flight Director Aero Terrascan, Ferry Ametia Pratama, explains, drone flight to the crater of Mount Agung is declared successful with about 30 minutes.
In this flight, the drone type AI 450 carries a multi-gas appliance equipped with a sensor.
This multi-gas sensor serves to take samples of gas released from the crater of Mount Agung. Then the gas content is read by the sensor, and the data will be used to analyze the liveliness of the mountain. How many examples of gas taken are CO2, H2O, and XO2.
“This multi-gas sensor from USGS, United States, is mounted on the plane, this tool will suck gas through a pipe, in which the sensor will read the gas sucked by this device,” said Feri Ametia Pratama when found at flight location.
From the sensor readings, he said, at first glance there is data tremaca. How much gas is sucked need to be processed again data. From the graph there is a difference.
“This will be analyzed by the PVMBG team with a team from USGS, which will soon be analyzed to determine the activity of the mountain,” he said.
He mentioned the drone flight is the main purpose for gas sampling.
“This material will be used for analysis, so get an idea of the current activities of Mount Agung, before we have done the flight, but just take pictures and video only,” he admitted.
Devy confirmed the drone flight to find out the gas levels in the crater of Mount Agung. Flight runs smoothly but the results are not maximized.
“Even though the drones have managed to get around on Mount Agung, we have not yet targeted the smoke, tomorrow (today, red) monitoring with the drones will be re-done,” he explained. (*)