STUDI GELOMBANG SEISMIK GEMPA VULKANIK GUNUNG SINABUNG UNTUK MENENTUKAN KARAKTERISTIK MEKANISME VULKANIK

Abstract

Mount Sinabung is a stratovolcano  mount  located in Karo, North Sumatra. Geographically located between 3o 10’ North Latitude and 98o 23,5’ East Longitude. This type of explosive volcanic eruptions.  Lava flowing from the stratovolcano is usually cool and harden before spreading far due to high viscosity.  Magma forming this lava  and acidic contain medium to high levels of silica. To observe volcanic earthquakes at Mount Sinabung is used 4 permanent stations are Sukanalu station (SKN), Laukawar (KWR), Sukameriah (SKM), and Mardingding (MRD).  Research has been conducted using primary data of volcanic earthquakes Sinabung in 2011 till June 2012. Based on the results of the spread of volcanic earthquake hypocenter obtained, previously has made the process of picking and determining the value to, tp  with error <0.2.  Results hypocenter distribution of volcanic earthquakes at Mount Sinabung is as much as about 500 volcanic earthquakes, and its earthquakes are concentrated at a depth of 0 to 6 km  asl. Mechanisms of volcanic magma chamber at Mount Sinabung is at a depth of about 12 km above sea level, is the crack area
(low frequency) and the area around the magma chamber (high frequency). Results of the average speed of P waves from the source to the receiver by a travel time curve is at 3.33
km/s. The dominant frequency of volcanic earthquakes Sinabung frequency value at station SKN smallest to largest on the station SKM is 0.28 Hz to 2.18 Hz.
 
Keywords :   Stratovolcano, Volcanic Earthquakes, Stations, Hypocenter, Magma Chamber, Travel Time, Frequency