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Seismic Lahar Characteristics of Merapi Volcano Post 2010 Eruption
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, EAGE-HAGI 1st Asia Pacific Meeting on Near Surface Geoscience and Engineering, Apr 2018, Volume 2018, p.1 - 5
Abstract
Merapi 2010 eruption ejected at least 130 million m3 volcanic material, mostly enter to Gendol River. More than 100 lahar events were generated around Merapi. Lahar at Merapi triggered by the rain intensity occurred at the summit. BPPTKG built the lahar flow monitoring station in order to mitigate the lahar disaster. The intention was to give early warning to the society. Lahar flows monitored using non-contact detection instrumentations installed near the rivers. These devices were geophones and IP-based camera.
This paper will present the seismic lahar characteristics recorded at Kali Gendol station. Events recorded on February 21, 28, April 23, 24 and also May 1, 2011, has been analyzed to know the characteristics. Most of the data had saturated amplitude due to the big magnitude lahar caused by the blocky materials. Seismic signal shows that the flow can be differentiated into single-pulse and multi-pulse events. Dominant frequency before the arriving of the lahar was fluctuating because of the human activity, traffic, etc., while the body of the lahar was 8–18 Hz. Maximum amplitude ranged between 1x104 – 1.9x104 Count (saturated). By knowing these lahar characteristics, amplitude and frequency result can also be used to refining the lahar early warning system.