L

ate on Friday, residents of Pangandaran in West Java had to relive the catastrophe of 2006, when a 6.8-magnitude earthquake caused a tsunami and killed at least 668 people.

Friday’s quake measured 6.9 on the Richter scale, and, having learned from the experience 11 years ago, the first thing the people of Pangandaran did was to flee to higher ground.

“People filled the streets and fled along the evacuation route to higher ground,” said Pangandaran native Andi Nuroni, who lives only 5 kilometers from the beach.

Soon after the tremor occurred, the Meteorology, Climatology and Geophysics Agency (BMKG) issued an early tsunami warning for parts of Java’s southern coastline, before revoking it two hours later.

Despite the fact that no tsunami was detected soon after the quake, many residents in and around Pangandaran panicked after seeing hoaxes and fake news on social media showing photos of what appeared to be residents driving their motorbikes through flooded streets.

The BMKG said the early warning was to alert residents on the possibility of a tsunami and not on the tsunami itself.

“We issue early warnings to urge residents to evacuate,” BMKG spokesman Hary Tirto Djatmiko said on Sunday. He implored residents only to get information from official BMKG channels.

National Disaster Mitigation Agency (BNPB) spokesman Sutopo Purwo Nugroho, however, said the country now had trouble watching the seas for tsunamis, as the monitoring buoys were damaged because of a lack
of maintenance.

He said all of the 22 early-warning buoys had been out of order since 2012, as the government had failed to allocate US$2.3 million for their annual maintenance.

“When a massive earthquake happens like [Friday night], we have to do it manually. Our staff members were standing at the sea shore to observe the waves for any signs of a tsunami,” Sutopo said.

He added that Indonesia currently depended on five buoys dispatched by India, which were installed in the waters off Aceh, another one operated by Thailand in the Andaman Sea, two operated by Australia in the waters south off Sumba and one belonging to the United States deployed to the north of Papua.

But Sutopo said Indonesia could rely on seismographic data to predict a tsunami after an earthquake.

“The seismograph is the main instrument to determine the source of an earthquake quickly, while ocean tides and buoys only provide supporting data,” he said.

Early tsunami warnings are based on earthquake modeling from seismographic data and are issued when an earthquake exceeds 7.0 in magnitude, with an epicenter less than 30 km deep and located on the subduction zone of the earth’s crust.

The operation of seismographs is handled by BMKG, while ocean tides are monitored by the Geospatial Information Agency, and the monitoring buoys are managed by the Agency for the Assessment and Application of Technology (BPPT).

Indonesia experiences frequent seismic and volcanic activity due to its position on the Pacific “Ring of Fire,” an arc of volcanoes and fault lines in the Pacific Basin, where tectonic plates often collide.

Besides raising awareness on the importance of building stronger houses in quake-prone areas, Sutopo said the government also needed to improve its disaster management system by putting more resources into the early warning system.

On Friday just before midnight, the BMKG recorded the Pangandaran earthquake at 6.9 on the Richter scale. On Saturday, the agency recorded three 3.4-magnitude aftershocks. The US Geological Survey said the epicenter of the quake was located at a depth of 92 km, about 52 km south-west of Tasikmalaya. Tremors were felt in Central and West Java.

As of Sunday afternoon, the death toll from the quake had reached four, with 36 injuries. At least, 200 people have been evacuated from their homes in Ciamis, West Java. (ami)