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Measurements of muon flux in Nirasaki debris avalanche deposit around the southern foot of the Yatsugadake volcanic chain in central Japan by using compact cosmic ray muon detectors

Satoshi Goto1, Shunji Obata1, Tadashi Gotoh2

  • Affiliations: 1Department of Civil and Environmental Engineering/University of Yamanashi, Japan 2 IBM Consulting Engineering Chain Transformation/IBM Japan, Ltd., Japan  

  • Presentation type: Poster

  • Presentation time: Tuesday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 184

  • Programme No: 3.5.43

  • Theme 3 > Session 5

Abstract

The Yatsugatake Nirasaki debris avalanche deposit (200-240ka) is widely distributed on the southern foot of the Yatsugatake Volcano. The source rock mass is mainly composed of andesitic lava and pyroclastic rocks from the Paleo-Yatsugatake Mountains Period, and many huge boulders of 50-300m in size are observed. On the other hand, Cosmic ray muon is one of the elementary particles raining down from space, and have enough energy to penetrate large structures. The technology of understanding the internal structure of objects using the properties of these muons is called muography (Nagamine, K.(1995), Suzuki, K. and Kanazawa, J.(2017), Tanaka, H.K.M. and Takeuchi, H.(2014)). The three-dimensional internal structure of volcanoes and the formation process of volcanoes can be discussed by a multi-directional muographic survey (Nagahara, S. et al., (2022)). Muon detectors used in previous studies are often large and inconvenient to carry, making it difficult to measure at multiple measuring locations. There are several methods for measuring muons, but they are generally performed using a large measuring device with scintillators arranged in parallel. The device is complex and expensive, which is a barrier to its application in increasing the number of observation objects. The main purpose of this study is to investigate the usefulness of a density estimation of Nirasaki debris avalanche deposit using a compact cosmic muon detectors. The density properties of debris avalanche deposit will be discussed by using the measured muon flux.