Signs of an Ancient Volcano Detected Under Mount Budheg in East Java

TheIndonesia.id - A team of geologists have recently detected what might be a crater of an ancient volcano after identifying rock structure in a massive volume under Mount Budheg in Tulungagung, East Java.

Geologists from Geological Agency at the Ministry of Energy and Mineral Resources said the rock structure, which was formed due to intrusion from the edge of the ancient volcanic crater, is estimated to be 20 to 30 million years old.

“The anomaly that we found from geophysical scanning is that it’s column-shaped, and [we] strongly believe it’s intrusive rock from the edge of ancient volcanic crater in Tulungagung,” head of the team Hidayat said in a discussion last week on March 23, as reported by Antara.

He explained that the scanning used magnetic gradiometer and ground penetrating radar (GPR) to map the distribution of underground objects, by using geological and archeological approaches.

Upon their study, the team found that the massive compact object under Mount Budheg wasn’t vertical as was previously assumed. Instead, it was tilted to the southeast.

Hidayat said the graphic images detected by the team through the devices indicated andesite structure formed when magma from the ancient volcano hardened underground.

“Two things led us to make that hypothesis, both from literature and satellite images,” Hidayat said.

Based on satellite images, there was an ancient crate in the southern area of Tulungagung with a diameter of 2.7 kilometers, and this signals the existence of a giant volcano which has been inactive and left behind a caldera.

According to Hidayat, to predict whether or not the ancient volcano will become active again on the future, seismicity – which is a sign of active volcano – can be a reference point.