Analisis sinyal seismik gunungapi semeru wawa timur, Desember 1993 � Februari 1994) dengan dekonvolusi homomorfik .untuk menentukan mekanisme sumbernya=Analysis of Seismic Signal Recorded at the Semeru Volcano (East Java

.Volcanic earthquakes of Mount Semeru (East Java) occurred between December, 1993 - February, 1994 have been investigated. The aim of the investigation is to study characteristics of seismic sources. A seismic station network consisted of 8 seismometers (1 hz vertical) was installed at eastern part of the volcano. The data was radio telemetered to a recording station at Jatisari, Lumajang. There were only 5 of the 8 seismometers having good condition. There were 17 volcanic earthquakes that could be determined their hypocentre. Based on the position, depth (about 3500 m) and low iteration error, four volcanic earthquakes are selected for further processing. Homomorphic Deconvolution analysis was used for separation the wavelet of the seismic sources from the impulse response of the medium. From this analysis, it was found that the medium between sources and stations close to be homogeneous. Time series model with AR(2) processes was applied to these wavelets in order to calculate frequency, damping coefficient, and Q factor. The results were frequency of these wavelets (3.96 ± 0,41) hz, damping coefficients (35.5 ± 0,3)10', and Q factors (4.1 ± 0,5). According to the Q factor value, the magma pocket might contain poor gas and water magma fluid. Laminar magma fluid flow was modelled to understand the source. From this model, it could be calculated that if the length of the cylinder magma pipe was 2000 m, the radii of the magma pocket was 40 m. Sudden gas bubble expansion might be the impulsive trigger of the volcanic earthquakes. This model lead to alternative radii of the magma pocket 40 m which was triggered by sudden gas bubble expansion having 2 - 6 m in radii. Keywords:seismic signal � homomorphic deconvolution � source mechanis