scholarly journals Muographic monitoring of hydrogeomorphic changes induced by post-eruptive lahars and erosion of Sakurajima volcano

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
László Oláh ◽  
Hiroyuki K. M. Tanaka ◽  
Gergő Hamar
Keyword(s):  
Cosmic Ray ◽  
Volcanic Hazards ◽  
Observation System ◽  
Passive Imaging ◽  
Sakurajima Volcano ◽  
Proportional Chamber ◽  
Gravity Driven ◽  
Continuous Deposition ◽  
Mass Increase

AbstractPost-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 cosmic-ray muon imaging (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 m$$^2$$ 2 ; 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.

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

2021 ◽  
Author(s):  
László Oláh ◽  
Hiroyuki K. M. Tanaka ◽  
Gergő Hamar
Keyword(s):  
Volcanic Hazards ◽  
Observation System ◽  
Passive Imaging ◽  
Sakurajima Volcano ◽  
Proportional Chamber ◽  
Gravity Driven ◽  
Continuous Deposition ◽  
Mass Increase ◽  
Significant Mass

Abstract 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.

scholarly journals Investigation of the limits of high-definition muography for observation of Mt Sakurajima

2018 ◽  
Vol 377 (2137) ◽  
pp. 20180135 ◽  
Author(s):  
László Oláh ◽  
Hiroyuki K. M. Tanaka ◽  
Gergő Hamar ◽  
Dezső Varga
Keyword(s):  
Multiple Scattering ◽  
Large Scale ◽  
Cosmic Ray ◽  
Average Density ◽  
Muon Flux ◽  
Observation System ◽  
High Definition ◽  
Proportional Chamber ◽  
Density Values ◽  
Density Map

A multi-wire proportional chamber-based muo- graphy observatory is under development for the monitoring of the internal structure of Mt Sakurajima in Kyushu, Japan. We investigated the limits of large-scale and high-definition muography. We adjusted the parameters of a modified Gaisser model and found that the spectral index of γ  =  − 2.64 and normalization factor of C  = 0.66 reproduce more accurately the measured fluxes than the original parameters at large thickness. A thickness and zenith angle-dependent correction is suggested to the measured muon flux due to the energy cut which is introduced to suppress the background particles. The multiple scattering of muons was simulated across the standard rock and sea-level atmosphere up to the distance of 5 km. We found that multiple scattering decreases from 10 mrad to 4 mrad across the rock due to the decrease in the steepness of muon spectra. The multiple scattering falls down to about 2 mrad after the object in the atmosphere due to the increase in observed arrival zenith angles. The 2 m 2 sized multi-wire proportional chamber-based Muographic Observation System (MMOS) was operating between February and June 2018. Three tracking systems operated reliably with tracking efficiencies of above 95%. The muon flux has been measured correctly down to 10 −3  m −2  sr −1  s −1 . The average density map of Mt Sakurajima has been measured with angular resolution of 12 mrad × 12 mrad (spatial resolution of 34 m × 34 m from the distance of 2.8 km). The average density values were found between 1.4 and 2 g cm −3 , except at the crater regions where lower densities were observed. This article is part of the Theo Murphy meeting issue ‘Cosmic-ray muography’.

Muographic Observation of Density Variations in the Vicinity of Minami-Dake Crater of Sakurajima Volcano

2019 ◽  
Vol 14 (5) ◽  
pp. 701-712
Author(s):  
László Oláh ◽  
Hiroyuki K. M. Tanaka ◽  
Gergő Hamar ◽  
Dezső Varga ◽  
◽  
...  
Keyword(s):  
Data Collection ◽  
Mass Density ◽  
Cosmic Ray ◽  
Total Surface Area ◽  
Average Density ◽  
Observation System ◽  
Length Variation ◽  
Sakurajima Volcano ◽  
Data Collection Period ◽  
Collection Period

Muography is an innovative imaging technique used for inspecting and monitoring density-length variations of large-sized natural or human-made objects based on the measurement of the absorption rate of cosmic-ray muons. The first large-sized, high-resolution muography observatory based on Multi-Wire Proportional Chamber (MWPC) technology is being developed to monitor the mass density variations in the vicinity of Minami-dake crater of Sakurajima volcano. We found that the track rates provided by five ongoing tracking systems with a total surface area of 4 m2 are stable within ±3% from the backward direction, which demonstrates that the MWPC-based Muographic Observation System (MMOS) is applicable for the detection of average density variations above 2%, which is well below the practical limit of 5%. We quantified the time resolution of the designed muography observatory by modeling the muon flux across the volcano; the average density-length variation of 5 (10)% is expected to be detected within 5–20 (2–8) days at a 1σ (68%) confidence level (CL) with an MMOS orientation of 10.86° above the horizon. An automated analysis framework was developed as a data base for raw data reconstruction, analysis, and preparation, and which is accessible via web-server. We observed a more than 2σ CL decrease in average density across the West side of Crater A during the ongoing data collection period. The observed density decrease suggests that the amount of material has decreased inside Crater A due to the consecutive eruptions of Minami-dake during the data collection period from November 30, 2018 to January 11, 2019.

Long-term negative trend in cosmic ray flux

2000 ◽  
Vol 105 (A1) ◽  
pp. 9-17 ◽  
Author(s):  
Yuri I. Stozhkov ◽  
Peter E. Pokrevsky ◽  
Victor P. Okhlopkov
Keyword(s):  
Cosmic Ray ◽  
Negative Trend ◽  
Cosmic Ray Flux

scholarly journals A method for multi-hazard mapping in poorly known volcanic areas: an example from Kanlaon (Philippines)

2013 ◽  
Vol 13 (8) ◽  
pp. 1929-1943 ◽  
Author(s):  
M. Neri ◽  
G. Le Cozannet ◽  
P. Thierry ◽  
C. Bignami ◽  
J. Ruch
Keyword(s):  
Land Use Planning ◽  
Volcanic Hazards ◽  
Mapping Method ◽  
Hazard Mapping ◽  
Hazard Map ◽  
Event Tree ◽  
Planning Decisions ◽  
Civil Defence ◽  
Term Data

Abstract. Hazard mapping in poorly known volcanic areas is complex since much evidence of volcanic and non-volcanic hazards is often hidden by vegetation and alteration. In this paper, we propose a semi-quantitative method based on hazard event tree and multi-hazard map constructions developed in the frame of the FP7 MIAVITA project. We applied this method to the Kanlaon volcano (Philippines), which is characterized by poor geologic and historical records. We combine updated geological (long-term) and historical (short-term) data, building an event tree for the main types of hazardous events at Kanlaon and their potential frequencies. We then propose an updated multi-hazard map for Kanlaon, which may serve as a working base map in the case of future unrest. The obtained results extend the information already contained in previous volcanic hazard maps of Kanlaon, highlighting (i) an extensive, potentially active ~5 km long summit area striking north–south, (ii) new morphological features on the eastern flank of the volcano, prone to receiving volcanic products expanding from the summit, and (iii) important riverbeds that may potentially accumulate devastating mudflows. This preliminary study constitutes a basis that may help local civil defence authorities in making more informed land use planning decisions and in anticipating future risk/hazards at Kanlaon. This multi-hazard mapping method may also be applied to other poorly known active volcanoes.

Long-term characterization of the Martian atmosphere and soil from cosmic ray effects in returned samples

Icarus ◽  
1981 ◽  
Vol 45 (1) ◽  
pp. 250-262 ◽  
Author(s):  
R.E. Arvidson ◽  
C.M. Hohenberg ◽  
J.R. Shirck
Keyword(s):  
Cosmic Ray ◽  
Martian Atmosphere ◽  
Ray Effects ◽  
Cosmic Ray Effects

The In situ Global Ocean Observing System for Climate (and Other Needs)

2015 ◽  
Vol 49 (2) ◽  
pp. 112-121
Author(s):  
Stephen R. Piotrowicz ◽  
David M. Legler
Keyword(s):  
Weather Forecasting ◽  
Spatial Scales ◽  
The Arctic ◽  
Global Ocean ◽  
Observation System ◽  
Ocean Management ◽  
Accuracy And Precision ◽  
Weather And Climate ◽  
Ocean Observing

AbstractThe Global Ocean Observing System (GOOS) is the international observation system that ensures long-term sustained ocean observations. The ocean equivalent of the atmospheric observing system supporting weather forecasting, GOOS, was originally developed to provide data for weather and climate applications. Today, GOOS data are used for all aspects of ocean management as well as weather and climate research and forecasting. National Oceanic and Atmospheric Administration (NOAA), through the Climate Observation Division of the Office of Oceanic and Atmospheric Research/Climate Program Office, is a major supporter of the climate component of GOOS. This paper describes the eight elements of GOOS, and the Arctic Observing Network, to which the Climate Observation Division is a major contributor. In addition, the paper addresses the evolution of the observing system as rapidly evolving new capabilities in sensors, platforms, and telecommunications allow observations at unprecedented temporal and spatial scales with the accuracy and precision required to address questions of climate variability and change.

The Long Term Cosmic Ray Variation Relevant to Solar Wind Structure in the Outer Heliosphere

1990 ◽  
pp. 199-203
Author(s):  
M.V. Alania ◽  
R.G. Aslamazashvili ◽  
T.B. Bochorishvili ◽  
L.I. Dorman ◽  
R.T. Guschina ◽  
...  
Keyword(s):  
Solar Wind ◽  
Cosmic Ray ◽  
Outer Heliosphere ◽  
Wind Structure ◽  
Solar Wind Structure
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