Current state of the seismic broadband network of Indonesia: Is it possible for the early warning system from a subaerial source-induced tsunami?

¹ Department of Marine Sciences, Faculty of Marine and Fisheries, Universitas Syiah Kuala, Banda Aceh 23111, Indonesia
² Tsunami and Disaster Mitigation Research Center (TDMRC), Universitas Syiah Kuala, Banda Aceh 23111, Indonesia
³ Research Center for Marine Sciences and Fisheries, Universitas Syiah Kuala, Banda Aceh 23111, Indonesia
⁴ Agency for Meteorology, Climatology, and Geophysics (BMKG), Jakarta 10610, Indonesia
⁵ Institute of Earth Science, Academia Sinica, Taipei 115, Taiwan

^* Corresponding author: haekal.azief.haridhi@unsyiah.ac.id

Abstract

Lesson learned from the Anak Krakatau volcanic eruption followed by the tsunami on 22 December 2018 has generated a huge gap in the readiness of the Indonesian early warning system to detect such an event. Consequently, the official was found it difficult to broadcast the right warning within a considerable time to the local residences to evacuate or take necessary actions, which resulted in the loss of life and properties. There were more than 430 people died, and countless properties were destroyed when the tsunami swept the coastlines of southern Sumatra and western Java. While, this event is among the perfect events to study about the subaerial slide since it was occurred on near-surface with moderate magnitude M5.9 and creates the subaerial slide during the process (flank collapsed), and the broadband seismic stations managed by the Agency for Meteorology, Climatology, and Geophysics (BMKG) are already established and record the signal. Usually, the seismic source from the eruption was not complicated, and the seismic signal that recorded by the BMKG broadband seismic stations should correspond to the subaerial slide processes. Since Indonesia is an archipelago nation, the seismic station managed by the BMKG is distributed on the island with a distance ranging from a couple of kilometers to a tenth of kilometers away between stations. For this reason, this study tries to highlight several important suggestions in order to improve the detection using the signal recorded by the BMKG broadband seismic stations relate to such an event.