Geomagnetic variation related to Sakurajima volcano eruption

Abstract:

Geomagnetic field has been studied for measuring precursor signals to understand earthquake events by geoscientists. Furthermore, analysis of geomagnetic data helps detect symptom of volcanic eruption. In this study, we process geomagnetic data for Sakurajima volcano case which erupted on Aug 18, 2013 with a large scale of eruption in Japan. This volcanic activity has an effect on geomagnetic data not only geomagnetic observatory in Japan but also in Korea. This study carries out that the geomagnetic variation has been analyzed using geomagnetic data from Cheongyang observatory in Korea and several geomagnetic observatories in Japan.

First, we compared the geomagnetic data directly from each component, then searching the difference by volcanic eruption. Secondly, we execute wavelet based semblance from geomagnetic data in order to confirm the correlation between geomagnetic data and effect from volcano activity.

As a result, geomagnetic diurnal variation is generally about 50 nT. However, It hardly shows geomagnetic variation on z component and displays about 15 nT on total component before Sakurajima volcano eruption at Kanoya geomagnetic observatory. Moreover, we could confirm uncorrelated event by wavelet based semblance analysis what estimated to volcano activity.

This study conducted to confirm geomagnetic variation related to volcano activity getting meaningful result.