A second tsunami warning that caused panic and sent residents in Labuhan Bay of Pandeglang regency, Banten, seeking shelter was caused by faulty sirens, according to the National Disaster Mitigation Agency (BNPB).

Tsunami warning sirens in Pandeglang started to sound at around 12:45 p.m. and prompted residents to run from the beach toward higher ground. Many residents also rushed to nearby tsunami shelters. 

"The BMKG [Meterology, Climatology and Geophysics Agency] did not issue any warning. The tsunami sirens in Lambuhan Bay, Labuhan district, Pandeglang regency, just started on its own without being activated by the BMKG or the BNPB," BNPB spokesperson Sutopo Purwo Nugroho told reporters on Sunday. "It is likely that a technical problem caused the sirens to sound on their own", he added.

The incident adds to a list of inoperative disaster early warning systems across Indonesia. After the earthquake and tsunami that hit Central Sulawesi earlier this year, it was revealed that the country's tsunami detection buoys had mostly been broken by vandalism. 

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The BMKG also said in a statement on Saturday that seismometers around the Anak Krakatau volcano had been damaged by an eruption. 

Sutopo added that the BMKG did not yet have the technology to detect tsunamis caused by underwater landslides or volcanic eruptions, which is what is believed to have happened in the Sunda Strait disaster.

"We should look to develop this technology as soon as possible," he said.