TimesAsiaNews.com | Jakarta – The National Research and Innovation Agency (BRIN) allegedly stopped the Tsunami monitoring program (Ina-Tews) which used a device called a buoy. How does the tool work? Previously, reports from one of the media alluded to the lack of activity in the monitoring room for the Indonesia Tsunami Observation Center (Ina-TOC) in the Soedjono Poesponegoro Building, on Jalan M.H Thamrin, Central Jakarta. This has been going on for one year.
In fact, the existence of Ina-TOC is a mandate from Presidential Regulation Number 93 of 2019 concerning Strengthening and Development of Earthquake Information Systems and Tsunami Early Warning. Tsunami monitoring at Ina-TOC is carried out by collecting data sent by tsunami detection devices in the middle of the sea, namely floating devices (Ina-Buoy), optical cables (Ina-CBT), and sound wave propagation (Ina-Cat).
The lack of activity feels ironic. This is because in May 2021 the Head of BMKG Dwikorita Karnawati and the Head of the Agency for the Assessment and Application of Technology (BPPT), which is now annexed by BRIN, were monitored by Hammam Riza. Dwikorita even praised the sophistication of the BPPT’s tsunami detection equipment including the buoys. This is because the BPPT tsunami buoy is equipped with Ocean Bottom Unit (OBU) technology which is placed on the seabed so that it can detect the presence or absence of tsunami waves.
“This tool is a verifier of the BMKG’s tsunami early warning model. During the M6.1 earthquake in Malang on April 10, the Buoy in the south of Malang detected a change in underwater hydrostatic pressure shortly after BMKG issued earthquake information,” said Dwikorita. “This means that this is verified, that the occurrence of an earthquake has an impact on changes in hydrostatic pressure under the sea,” he continued.
BRIN has so far not responded to a request for comment regarding the alleged deactivation of this buoy.
According to the BPPT website, the buoys themselves are located and operating in 13 locations throughout Indonesia. One of them is in the waters near Mount Anak Krakatau (GAK).
This buoy is the result of BPPT’s innovative activities starting from the design, construction, testing, installation, and operational processes. Outside Indonesia, the Buoy is also used by the Australian Meteorological Agency (BoM). Quoting the official BoM website, the buoy works with two components: pressure sensors that are under the sea and on the surface.
Underwater sensors are useful for measuring changes in the height of the water column by detecting changes in water pressure.
These changes are then forwarded to the buoys on the surface via acoustic telemetry before being forwarded again via satellite to the tsunami monitoring center.
In placing buoys in the ocean, there are several things that must be considered. Buoys, for example, must be placed far enough from the epicenter of the earthquake to ensure there is no interference between the earthquake signal at the buoy and the sea level signal from the tsunami. Buoys must also be placed in water with a depth of more than 3000 meters. This is useful for ensuring that the signal is not contaminated by other types of waves that are at shallower heights.
The effectiveness of the buoys in detecting tsunamis has also been proven in several incidents. Quoting an article by Chinese expert, Lianda Zhao in Elsevier, buoys, among other things, have been proven to have detected the tsunami in Japan in 2011.
“The important role of the tsunami buoy has been proven in several tsunami events in recent years. This system accurately predicted the outcome of the 11 March 2011 Japan tsunami,” the expert wrote.
“The State Oceanic Administration (SOA) of China has also placed two buoys in the South China Sea, which also play an important role in warning against the tsunami,” continued the expert team. (**)
cnnind/timesasianews
