Anisotropy of Magnetic Susceptibility and Preferred Pore Orientation in Lava Flow from the Ijen Volcanic Complex, East Java, Indonesia

Fadhli Ramadhana Atarita,Fourier Dzar Eljabbar Latief,Satria Bijaksana,Nuresi Rantri Desi Wulan Ndari,Aditya Pratama,Silvia Jannatul Fajar,Reyhan Fariz Taqwantara

doi:10.3390/geosciences9070304

Fadhli Ramadhana Atarita, Fourier Dzar Eljabbar Latief + Show 5 more

Open Access

https://doi.org/10.3390/geosciences9070304

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Journal: Geosciences	Publication Date: Jul 11, 2019
Citations: 2	License type: CC BY 4.0

Affiliation: Bandung Institute of Technology

Abstract

Anisotropy of magnetic susceptibility (AMS) has been used in various studies related to interpreting the direction of lava flow, some of which have shown ambiguity with regard to the data generated. In this study, we explored an alternative option to support the aforementioned application, using lava flow type igneous rock samples from the Ijen Volcanic Complex, East Java, Indonesia. We have investigated the preferred rock pore orientations from micro-computed tomography (μCT) images and quantified their directions. We then calculated their correlation with AMS data by calculating the angle between preferred pore orientation. The axis with the smallest gap to the preferred pore orientation of each sample was assumed to imply lava flow direction. Different lava flow direction preferences were obtained from different magnetic ellipsoids. Another important factor for consideration is the relative vertical position of the sampling site within a single lava flow unit. Only one out of five samples (ANY2) show good quantitative conformity between AMS data, preferred pore orientation, and topographical slope, despite these limitations. Our results point to a direction that seems to be correct and coherent on a physical basis. Additional research would likely clarify the issues involved. This encourages us to explore and work further in this field of research.

Highlights

Anisotropy of magnetic susceptibility (AMS) is defined as the characteristic of a rock that has different values of magnetic susceptibility if measured by different angles or directions
ANY4 and specimens that were used in μCT
These diagrams show the distribution of the inclination specimens that were used in μCT imaging

Summary

Introduction

Anisotropy of magnetic susceptibility (AMS) is defined as the characteristic of a rock that has different values of magnetic susceptibility if measured by different angles or directions. This particular parameter has been used in previous studies, most commonly to determine lava flow direction [1,2,3,4,5,6,7,8,9,10]. The study in reference [11] on Xitle lava in Mexico showed no correlation between lava flow direction and the maximum or intermediate susceptibility axes These contradictory results could be accommodated by considering the local lava flow direction. The correlation between AMS and lava flow direction is undeniable [13]

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