(This volcano is very large and high. On the Indonesian mainland, there are no mountains as high as this except Mount Jayawijaya in Papua!)
The team consisting of a combination of Indonesian, US and French geologists managed to find a giant volcano under the western waters of Sumatra. The volcano is 50 km in diameter and 4,600 meters high and is 330 km west of Bengkulu City.
These geologists are from the Agency for the Assessment and Application of Technology (BPPT), the Indonesian Institute of Sciences (LIPI), the Department of Energy and Mineral Resources, CGGVeritas and the IPG (Institute de Physique du Globe) in Paris.
"This volcano is very big and tall. In mainland Indonesia, there are no mountains this high except Mount Jayawijaya in Papua, "said Director of the BPPT Natural Resource Inventory Technology Center Yusuf Surachman.
This underwater volcano is located in the Sunda Trench southwest of Sumatra, 330 km from Bengkulu, at a depth of 5.9 km with a peak at a depth of 1,280 meters above sea level. Although this mountain is known to have a caldera that marks it as a volcano, experts claim that they have not yet known the level of activity of this underwater volcano.
"However underwater volcanoes are very dangerous if they erupt," he said. The survey using CGGVeritas's advanced Geowave Champion seismic vessel is the first in the world because it uses the longest streamer, 15 km, than has been done by seismic survey vessels.
The purpose of this survey is to find out the deep geological structure (penetration of up to 50 km) which includes the Sunda Trench, accretion prism, outer arc high, and fore arc basin Sumatran waters.
Since the last earthquake and tsunami in 2004 and other aftershocks, there have been many structural changes in the Sumatran waters which have attracted many foreign researchers.
A team of experts from Indonesia, the US and France then worked together to map the deep geological structure to better understand the source and mechanism of the tsunami triggering earthquake using deep seismic images.
Found When Mapping the Seabed
BPPT, through its marine survey technology center, has searched and mapped the sea floor in the Indian Ocean, to the south of Java. Locations that are 'coincidental' are found in the volcano in the Indian Ocean or in the west off the coast of Bengkulu.
"There are indications that this volcano refers to the discovery in 2009," said survey staff at the marine technology center, BPPT, Dwi Hariyanto in Jakarta. He continued, BPPT had carried out the mapping twice.
"First of October 2010, using the Barunajaya 3 ship, 12Khz multibeam equipment. Then, Barunajaya 4, in December 2010 with 50Khz multibeam power. This multibeam equipment is for medium water, "he explained.
Based on the images obtained, there are 2 mountain peaks with a diameter of approximately 40-50 kilometers.
In the southern mountain, the peak is at 1,300 meters and in the north, the peak is 1,400 meters below sea level.
BPPT also conducts oceanography research, CTD to measure water temperature. He concluded, BPPT correctly confirmed the findings of the mountain monument, but did not find anomalies at water temperatures. "In order to be surveyed in more detail, (knowing) the volcano is active or not, and naming the mountain," he said.
If Erupted, Is It Potential for a Tsunami?
According to Sri Hardiastuti, the Center for Marine Survey Technology, BPPT, the existence of underwater volcanoes is also likely to cause a tsunami. According to him, this still has to be studied whether the shape of the bulge comes from oceanic or continental plate material. "Need material samples," he said.
If it is true that it is an active volcano, then there must be anticipatory steps. He said, there are differences between volcanoes on land and at sea. "(For) earthquake, obviously. A tsunami can happen, "he added.
The tsunami potential also depends on the size of the collapse or earthquake. This was also justified by Wahyu W. Pandoe, head of the operational program, Ocean Climate and Tsunami Buoy, BPPT. According to him, if a strong earthquake appears on the seabed, then the possibility of a tsunami can also occur.
According to him, this bulge in the seabed can arise due to the subduction process ('subduction'). Nevertheless, he appealed to all parties and the public not to worry, because the volcano was active or not, it could only be determined after further research.
The survey should have been held in 2012, he continued, but was constrained. Thus, these obstacles delay the implementation of research. BPPT will prepare a follow-up survey, and collaborate with relevant parties, including the field of Volcanology in Bandung.
Concerned about the emergence of natural disasters related to the alleged active volcano under the Bengkulu Sea, it still has to be examined more deeply. The Agency for the Assessment and Application of Technology (BPPT) will continue to conduct research, such as taking rock samples and examining the temperature of water around the bottom of the Bengkulu sea.
Deputy Head of BPPT in the field of Natural Resource Development, Ridwan Djamaludin explained, "Mount is not only on land but also on the sea. The mountain does not connote active volcanoes. There are mountains that are not volcanoes, they are formed by tectonic processes, "Ridwan explained.
He said, in general, the shape of a volcano has a bulge, some are elongated. Further research is needed to ascertain whether this form of bulge is an active volcano. "We don't get data that indicates this mountain is active," he said.
According to him, the signs of an active mountain will cause high environmental temperatures. "But there is no indication that there is no sign of high temperatures. We confirm there is a form (the mountain) in the west of Bengkulu (see via satellite), we don't call this an active volcano, "he explained.