MEASUREMENTS COMBINATION OF ELASTIC ANISOTROPY AND ANISOTROPY OF MAGNETIC SUSEPTIBILITY ON THE CASE STUDY IN IGNEOUS ROCK OF LAVA FLOW TYPE FROM IJEN VOLCANIC COMPLEX, EAST JAVA

• Main Author: RANTRI DESI WULAN NDARI (NIM: 12314060), NURESI
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/29778
• Institution: Institut Teknologi Bandung

<p align="justify"> Research into the anisotropy parameters of rock is a necessary part in geophysical investigations. This research is a preliminary study which aims to find the relationship between elastic anisotropy and anisotropy of magnetic susceptibility in igneous rock of lava flow type with MR1 code from Ijen Volcanic Complex. In addition, this study is aims to interpret preferred orientation in igneous rock of lava flow type with MR1 code based on the integration of anisotropy measurement results with the supported results from microcomputed tomography (&#956;CT) analysis, petrography analysis and geological data. This research has never been done before. The distinction of this research is the combination of several methods that usually work independently become a new methods that can be expected to interpret the preferred orientation in rock more accurately. <br /> <br /> This study is divided into several stages consist of field activities to get the samples, preparation of measurements samples, seismic wave velocity measurements (Vp and Vs) on the three main perpendicular axes of a cube-shaped sample to get the direction of maximum velocity and elastic anisotropy parameter values, magnetic susceptibility measurements on six directions for each cylindrical sample to determine the direction of maximum suseptibility (magnetic mineral orientation) and AMS parameter values, petrography analysis on the all sides of the cube in order to observe preferred orientation in mineral and &#956;CT analysis in a core sample to examine the porosity trend of rocks. <br /> <br /> This study show the relationship between AMS and elastic anisotropy in igneous rocks of lava flow type which indicated by positive correlation between the direction of maximum magnetic susceptibility and maximum velocity. Based on the results, MR1 sample has elastic anisotropy degree ranging from 2,6 % - 6,6 % for P waves and 2,2 % - 4 % for S waves and anisotropy of magnetic susceptibility degree around 2,6 % - 5,4 % . The integration of all measurement results including the direction of maximum velocity, direction of maximum magnetic susceptibility, preferred orientation in mineral, porosity trend, and dip direction of sheeting joint indicate the existence of preferred orientation in igneous rock of lava flow type with MR1 code towards NE-SW. One possible cause of such preferred orientation is the direction of the lava flow. <p align="justify">