Gempatan Activities Are Still Fluctuating, Weigh Crater Status And Sileri In Dieng Are Still Alert

The Dieng highlands, Wonosobo Regency, Central Java (Central Java). (Unsplash)

The Center for Volcanology and Geological Hazard Mitigation (PVMBG) stated that until now, the Sileri Crater and Weigh Crater in the Dieng Plateau (Plato), Banjarnegara Regency, Central Java (Central Java), are still on alert status.

"Until now there has been no evaluation of the status of the two craters," said officers of the Dieng PVMBG Volcano Observation Post (PGA) Aziz Yuliawan, Monday, January 30.

Nevertheless, he admitted that in the last few days, the concentration of toxic gas released by Weigh Crater tends to decrease when compared to when the status was increased from Active Normal to Alert on Friday, January 13, at 23.00 WIB.

However, in terms of seismic activity, he said, it is still fluctuating because on Saturday, January 28, there were 37 local tectonic earthquakes with an amplitude of 6.7-42.7 millimeters, a delay time (S-P) of 0.4-2.2 seconds, and a long earthquake of 6-17.8 seconds, while on Sunday (29/1) there were 23 local tectonic earthquakes with an amplitude of 10.7-42.7 millimeters, an S-P of 0.5-1.48 seconds, and a long earthquake of 4.6-27.3 seconds.

Asked about the spate of tectonic earthquakes that occurred on Sunday evening January 28 and Monday 30 Jnauari in the morning, he said that based on observations, until now there has been no earthquake impact on the increase in Dieng's activities, especially the Weigh Crater and Sileri Crater.

Based on data from the Meteorology, Climatology and Geophysics Agency (BMKG), the Dieng area on Sunday, January 29, at 21:28 WIB, was rocked by a tectonic earthquake with a magnitude of 2.3 centered on land at a distance of 17 kilometers northwest of Wonosobo with a depth of 10 kilometers.

Meanwhile, on Monday, January 30, at 04.10 WIB, there was a tectonic earthquake with a magnitude of 2.6 centered on land at a distance of 11 kilometers northeast of Wonosobo with a depth of 6 kilometers.

"Until now there has been no (earthquake impact)," said Aziz.

Regarding the evaluation of the status of the Weigh Crater, he said it would likely be done if its seismic activity was normal or approaching normal conditions even though its toxic gas concentration tended to decrease.

In normal Active conditions, he said, seismic activity in Weigh Crater only ranges from one to two local technonic earthquakes per day.

In addition to Weigh Crater, he continued, PVMBG also has no plans to evaluate Alert status at Sileri Crater even though the crater temperature has tended to be stable in recent days.

"The current temperature tends to be at the baseline (baseline or normal condition, ed.) Sileri Crater which ranges from 65-70 degrees Celsius," he said.

He suspects that the rain that has often occurred in recent times has an impact on increasing the volume of water in Sileri Crater, affecting the drop in temperature.

Aziz estimates that the rain will not result in landslides that can clog water vaporways in Sileri Crater.

"If it rains with a certain intensity, more than 20 millimeters, maybe the water can carry soil. Now the rain is frequent but not heavy," he explained.

Because the Weigh Crater and Sileri Crater are still vigilant, he appealed to the public to continue to pay attention to the recommendations that have been issued by PVMBG.

In this case, PVMBG recommends that people and tourists not approach Sileri Crater at a distance of 1 kilometer from the crater's lips.

The community is also recommended not to approach the southwest, south, and southeast of the Weigh Crater within 500 meters and be vigilant if digging the soil around the Weigh Crater in order to avoid the flow of CO2 gas which is very dangerous for life.

In addition, the public and tourists should not enter the craters in the Dieng Complex which can have the potential for a phreatic eruption in the form of mud bursts or material ejections, as well as craters with high concentrations of volcanic gas and dangerous for life.