The natural warning signs of tsunami earthquake in Indonesia: case of the 2006 Cilacap event

Natural warning signs and self-evacuation are essential to save lives in the event of a tsunami caused by an earthquake, especially if there are no clear early signs for example ground shaking. This paper explores the participants’ experiences focusing on how participants’ perceptions and responses to what they felt, saw or heard before seeing the first wave of 2006 tsunami in Cilacap, Indonesia. Using a phenomenological approach, this paper analyzes the stories of ten participants in three sub-districts, namely Cilacap Selatan, covering islands of Nusakambangan, Adipala, and Binangun. The tsunami was caused by a slow-motion earthquake, so people did not feel the ground shaking. The participants did not recognise natural signs of a tsunami, so they ignored them. Before seeing the first wave, the witness heard sound of explosions, extreme low tide, unusual animal behavior around, the appearance of a large number of marine products – lobsters (Crustacea) and sea shells (Mytilus spp.), and unusual color and shape of the waves. These signs should be socialised to the community in tsunami-prone areas, thereby increasing community’s disaster mitigation capacity. This study presents some natural warning signs that have not been reported by previous studies.