Plug Formation Imaged Beneath the Active Craters of Sakurajima Volcano With Muography

Oláh, L.; Tanaka, Hiroyuki; Ohminato, Takao; Hamar, G.; Varga, D.

doi:10.1029/2019gl084784

Cited by 33 publications

(41 citation statements)

References 32 publications

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“…Muography observation system at Sakurajima volcano. The muography observation system (MOS) 4 was installed at Sakurajima Muography Observatory (SMO) 22 . Figure 1(A-D) respectively show the location of the measurement site, a topographic map of the measurement site, and a cross-sectional view of Sakurajima volcano.…”

Section: Resultsmentioning

confidence: 99%

Pilot study of eruption forecasting with muography using convolutional neural network

Nomura

Nemoto

Hayashi

et al. 2020

Sci Rep

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Muography is a novel method of visualizing the internal structures of active volcanoes by using highenergy near-horizontally arriving cosmic muons. the purpose of this study is to show the feasibility of muography to forecast the eruption event with the aid of the convolutional neural network (cnn). in this study, seven daily consecutive muographic images were fed into the cnn to compute the probability of eruptions on the eighth day, and our cnn model was trained by hyperparameter tuning with the Bayesian optimization algorithm. By using the data acquired in Sakurajima volcano, Japan, as an example, the forecasting performance achieved a value of 0.726 for the area under the receiver operating characteristic curve, showing the reasonable correlation between the muographic images and eruption events. our result suggests that muography has the potential for eruption forecasting of volcanoes. Muography is a newly developed imaging technique utilizing high-energy near-horizontally arriving cosmic muons and enables us to visualize the internal structures of large objects. Muography produces a projection image (hereafter, muogram) of a large body by mapping out the number of muons that are transmitted through it. Muograms were first used in 1970 by Alvarez et al. to search for hidden chambers in the Chephren's Second Pyramid 1. Almost forty years later, muograms were first used to explore the internal structures of volcanoes 2. Muograms depicting the internal structures of a volcano are of particular importance because they may be used in the study of eruption dynamics 3. The first experimental evidence discovered using muograms was obtained by studying the summit of Mount Asama, Japan 2. The observation, in conjunction with the observation of a low-density magma pathway imaged underneath a solidified magma deposit, confirmed that muograms could resolve a volcano structure with more precision than the preexisting geophysical techniques. Since this first experimental study on the internal structure of volcanos in 2007, similar experiments have been carried not only in Japan 3-6 but also in the US 7 and Europe 8-11. Eruption forecasting is one of the most critical tasks in modern volcanology 12,13. For these tasks, many methods based on statistical algorithms or machine learning have been reported 14-19. These methods use data such as seismic activity, ground deformation, and gas emission. However, to the best of our knowledge, there has been no literature on eruption forecasting using muograms. Muography is conceptually similar to standard X-ray radiography. In the field of medical image analysis, including the analysis of X-ray radiographs, deep learning has been shown to achieve remarkable results 20,21. We expect that volcanic eruptions can also be forecasted by applying deep learning to muograms. The purpose of this study is to show the feasibility of eruption forecasting using muograms with deep learning. We focused on muographic data acquired at Sakurajima volcano, Japan, between 2014 and 2016 when it was most ac...

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Section: Resultsmentioning

confidence: 99%

Pilot study of eruption forecasting with muography using convolutional neural network

Nomura

Nemoto

Hayashi

et al. 2020

Sci Rep

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“…The burial mound was originally surrounded by a double moat, but most of this moat was buried in the past, and only a part of it currently remains. The landslide deposits originating from the sediments in the moat were dated, and the results were 1420-1510 CE using a method of C 14 dating (Sangawa and Miyazaki, 2001). Since it is known that the Fushimi earthquake occurred in 1596, this burial mound collapse was thought to have been triggered by this earthquake (Sangawa and Miyazaki, 2001).…”

Section: Observationmentioning

confidence: 99%

“…The result is a pattern of the contrast in the density distribution inside the objects, which is projected onto a 2-dimensional plane. Muography has been applied to the imaging of the internal structure of volcanoes (Tanaka et al, 2007(Tanaka et al, , 2009(Tanaka et al, , 2014Lesparre et al, 2012;Oláh et al, 2019), cultural heritage sites, including the Giza pyramids (Cheops and Chephren), Egypt, the Prambanan temples, Indonesia, Mount Echia, Italy, and Santa Maria del Fiore, Italy (Alvarez et al, 1970;Hanazato and Tanaka, 2016;Tanaka and Ohshiro, 2016;Morishima et al, 2017;Guardincerri et al, 2018;Cimmino et al 2019), industrial plants (Tanaka, 2013), and other natural (Tanaka et al, 2011;Oláh et al, 2012;Schouten, 2018) and man-made structures (Mahon et al, 2018). Prior works have focused on searching for undiscovered chambers or the total weight of the heritage site.…”

Section: Introductionmentioning

confidence: 99%

Muography as a new tool to study the historic earthquakes recorded in ancient burial mounds

Tanaka

Sumiya

Oláh

2020

Geosci. Instrum. Method. Data Syst.

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Abstract. Bidirectional muographic measurements were conducted at the Imashirozuka burial mound, Japan. The mound was built in the beginning of the 6th century as a megalithic tomb and later collapsed after a landslide caused by the 1596 Fushimi earthquake, one of the largest earthquakes that has occurred in Japan over the last few centuries. The measurements were conducted in order to find evidence of this past disaster recorded in this historical heritage site. As a result, the vertical low-density regions were found at the top of the mound. These regions were interpreted as large-scale vertical cracks that caused the translational collapse process behind the rotational landslide that was already found in prior trench-survey-based works. These results indicate that there was an intrinsic problem with the stability of the basic foundation of the Imashirozuka mound before the 1596 Fushimi earthquake.

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“…The applicability of muography has already been demonstrated for volcano imaging thanks to the recent progress in the development of observation instruments [21][22][23][24][25][26][27][28][29][30] and imaging techniques [31][32][33][34] . Various volcanic phenomena, such as magma ascent and descent 35 , the degassing process 36 , plug formation 37 , magma intrusion into lava domes 38 , tectonic evolution 39 , hydrothermal processes 40,41 or long-term tephra deposition 42 , have already been measured with muographic imaging.…”

Section: Introductionmentioning

confidence: 99%

“…Although this muographic measurement of tephra thickness demonstrated that muography could provide useful input for the determination of the magnitude and intensity of eruptions, the limited time resolution of the experiment was not sufficient to reveal the hydrogeomorphic changes which occurred on the volcanic edifice. In this work, we exploit the technological advantages, specifically the upgraded detection acceptance and angular resolution, of the Multi-wire-proportional-chamber (MWPC)-based Muography Observation System (MMOS) 33,37,43 of Sakurajima Muography Observatory (SMO) 33,34,37,42 to observe the short-term erosions of the volcanic edifice that can weaken and destabilize the upper parts of the volcano. Muographic monitoring of hydrogeomorphic responses to the disturbances of volcano landscapes may contribute to the assessment of the threats posed by indirect volcanic hazards.…”

Section: Introductionmentioning

confidence: 99%

Muographic Monitoring of Hydrogeomorphic Changes Induced by Post-Eruptive Lahars and Erosion of Sakurajima Volcano

Oláh

Tanaka

Hamar³

2021

Preprint

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Post-eruptive destabilization of volcanic edifices by gravity driven debris flows or erosion can catastrophically impact the landscapes, economies and human societies surrounding active volcanoes. In this work, we propose muography as a tool for the remote monitoring of hydrogeomorphic responses to volcano landscape disturbances. We conducted the muographic monitoring of Sakurajima volcano, Kyushu, Japan and measured continuous post-eruptive activity with over 30 lahars per year. The sensitive surface area of the Multi-Wire-Proportional-Chamber-based Muography Observation System was upgraded to 7.67 m2 ; this made it possible for the density of tephra within the crater region to be measured in 40 days. We observed the muon flux decrease from 10 % to 40 % through the different regions of the crater from September 2019 to October 2020 due to the continuous deposition of tephra fallouts. In spite of the long-term mass increase, significant mass decreases were also observed after the onsets of rain-triggered lahars that induced the erosion of sedimented tephra. The first muographic observation of these post-eruptive phenomena demonstrate that this passive imaging technique has the potential to contribute to the assessment of indirect volcanic hazards.

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Plug Formation Imaged Beneath the Active Craters of Sakurajima Volcano With Muography

Cited by 33 publications

References 32 publications

Pilot study of eruption forecasting with muography using convolutional neural network

Pilot study of eruption forecasting with muography using convolutional neural network

Muography as a new tool to study the historic earthquakes recorded in ancient burial mounds

Muographic Monitoring of Hydrogeomorphic Changes Induced by Post-Eruptive Lahars and Erosion of Sakurajima Volcano

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