Locating rock slope failures along highways and understanding their physical processes using seismic signals

<p>Regional monitoring of rock slope failures using the seismic technique is rarely undertaken due to significant source location errors; this method also still lacks the signal features needed to understand events of this type because of the complex mass movement involved. To better comprehen...

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Main Authors: J.-M. Chang, W.-A. Chao, H. Chen, Y.-T. Kuo, C.-M. Yang
Format: Article
Language:English
Published: Copernicus Publications 2021-06-01
Series:Earth Surface Dynamics
Online Access:https://esurf.copernicus.org/articles/9/505/2021/esurf-9-505-2021.pdf
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author J.-M. Chang
W.-A. Chao
W.-A. Chao
W.-A. Chao
H. Chen
H. Chen
Y.-T. Kuo
C.-M. Yang
author_facet J.-M. Chang
W.-A. Chao
W.-A. Chao
W.-A. Chao
H. Chen
H. Chen
Y.-T. Kuo
C.-M. Yang
author_sort J.-M. Chang
collection DOAJ
description <p>Regional monitoring of rock slope failures using the seismic technique is rarely undertaken due to significant source location errors; this method also still lacks the signal features needed to understand events of this type because of the complex mass movement involved. To better comprehend these types of events, 10 known events along highways in Taiwan were analyzed. First, a hybrid method (GeoLoc) composed of cross-correlation-based and amplitude-attenuation-based approaches was applied, and it produced a maximum location error of 3.19 <span class="inline-formula">km</span> for the 10 events. We then analyzed the ratio of local magnitude (<span class="inline-formula"><i>M</i><sub>L</sub></span>) and duration magnitude (<span class="inline-formula"><i>M</i><sub>D</sub></span>) and found that a threshold of 0.85 yields successful classification between rock slope failure and earthquake. Further, GeoLoc can retrieve the seismic parameters, such as signal amplitude at the source (<span class="inline-formula"><i>A</i><sub>0</sub></span>) and <span class="inline-formula"><i>M</i><sub>L</sub></span> of events, which are crucial for constructing scaling law with source volume (<span class="inline-formula"><i>V</i></span>). Indeed, <span class="inline-formula">Log(<i>V</i>)</span> <span class="inline-formula">=</span> 1.12 <span class="inline-formula"><i>M</i><sub>L</sub></span> <span class="inline-formula">+</span> 3.08 and <span class="inline-formula"><i>V</i></span> <span class="inline-formula">=</span> 77 290 <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M13" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi>A</mi><mn mathvariant="normal">0</mn><mn mathvariant="normal">0.44</mn></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="17pt" class="svg-formula" dspmath="mathimg" md5hash="bbe2ff3286b8731e8c9c326689d0b922"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="esurf-9-505-2021-ie00001.svg" width="25pt" height="17pt" src="esurf-9-505-2021-ie00001.png"/></svg:svg></span></span> derived in this study provide the lower bound of volume estimation, as the seismic parameters based on peak amplitudes cannot represent the full process of mass loss. Second, while video records correspond to seismic signals, the processes of toppling and sliding present column- and V-shaped spectrograms, respectively. The impacts of rockfall link directly to the pulses of seismic signals. Here, all spectrogram features of events can be identified for events with volumes larger than 2000 <span class="inline-formula">m<sup>3</sup></span>, corresponding to the farthest epicenter distance of <span class="inline-formula">∼</span> 2.5 <span class="inline-formula">km</span>. These results were obtained using the GeoLoc scheme for providing the government with rapid reports for reference. Finally, a recent event on 12 June 2020 was used to examine the GeoLoc scheme's feasibility. We estimated the event's volume using two scalings: 3838 and 3019 <span class="inline-formula">m<sup>3</sup></span>. These values were roughly consistent with the volume estimation of 5142 <span class="inline-formula">m<sup>3</sup></span> from the digital elevation model. The physical processes, including rockfall, toppling, and complex motion behaviors of rock interacting with slope inferred from the spectrogram features were comprehensively supported by the video record and field investigation. We also demonstrated that the GeoLoc scheme, which has been implemented in Sinwulyu catchment, Taiwan, can provide fast reports, including the location, volume, and physical process of events, to the public soon after they occur.</p>
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spelling doaj.art-27f45bc399b9455291b5a43c7fc0da742022-12-21T21:25:46ZengCopernicus PublicationsEarth Surface Dynamics2196-63112196-632X2021-06-01950551710.5194/esurf-9-505-2021Locating rock slope failures along highways and understanding their physical processes using seismic signalsJ.-M. Chang0W.-A. Chao1W.-A. Chao2W.-A. Chao3H. Chen4H. Chen5Y.-T. Kuo6C.-M. Yang7Department of Geosciences, National Taiwan University, Taipei 10617, TaiwanDepartment of Civil Engineering, National Chiao Tung University, Hsinchu 30010, TaiwanDisaster Prevention and Water Environment Research Center, National Chiao Tung University, Hsinchu 30010, TaiwanDepartment of Civil Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, TaiwanDepartment of Geosciences, National Taiwan University, Taipei 10617, TaiwanNational Science and Technology Center for Disaster Reduction, New Taipei 23143, TaiwanDepartment of the Earth and Environmental Sciences, National Chung-Cheng University, Chiayi County 621, TaiwanDepartment of Civil and Disaster Prevention Engineering, National United University, Miaoli 36003, Taiwan<p>Regional monitoring of rock slope failures using the seismic technique is rarely undertaken due to significant source location errors; this method also still lacks the signal features needed to understand events of this type because of the complex mass movement involved. To better comprehend these types of events, 10 known events along highways in Taiwan were analyzed. First, a hybrid method (GeoLoc) composed of cross-correlation-based and amplitude-attenuation-based approaches was applied, and it produced a maximum location error of 3.19 <span class="inline-formula">km</span> for the 10 events. We then analyzed the ratio of local magnitude (<span class="inline-formula"><i>M</i><sub>L</sub></span>) and duration magnitude (<span class="inline-formula"><i>M</i><sub>D</sub></span>) and found that a threshold of 0.85 yields successful classification between rock slope failure and earthquake. Further, GeoLoc can retrieve the seismic parameters, such as signal amplitude at the source (<span class="inline-formula"><i>A</i><sub>0</sub></span>) and <span class="inline-formula"><i>M</i><sub>L</sub></span> of events, which are crucial for constructing scaling law with source volume (<span class="inline-formula"><i>V</i></span>). Indeed, <span class="inline-formula">Log(<i>V</i>)</span> <span class="inline-formula">=</span> 1.12 <span class="inline-formula"><i>M</i><sub>L</sub></span> <span class="inline-formula">+</span> 3.08 and <span class="inline-formula"><i>V</i></span> <span class="inline-formula">=</span> 77 290 <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M13" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi>A</mi><mn mathvariant="normal">0</mn><mn mathvariant="normal">0.44</mn></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="17pt" class="svg-formula" dspmath="mathimg" md5hash="bbe2ff3286b8731e8c9c326689d0b922"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="esurf-9-505-2021-ie00001.svg" width="25pt" height="17pt" src="esurf-9-505-2021-ie00001.png"/></svg:svg></span></span> derived in this study provide the lower bound of volume estimation, as the seismic parameters based on peak amplitudes cannot represent the full process of mass loss. Second, while video records correspond to seismic signals, the processes of toppling and sliding present column- and V-shaped spectrograms, respectively. The impacts of rockfall link directly to the pulses of seismic signals. Here, all spectrogram features of events can be identified for events with volumes larger than 2000 <span class="inline-formula">m<sup>3</sup></span>, corresponding to the farthest epicenter distance of <span class="inline-formula">∼</span> 2.5 <span class="inline-formula">km</span>. These results were obtained using the GeoLoc scheme for providing the government with rapid reports for reference. Finally, a recent event on 12 June 2020 was used to examine the GeoLoc scheme's feasibility. We estimated the event's volume using two scalings: 3838 and 3019 <span class="inline-formula">m<sup>3</sup></span>. These values were roughly consistent with the volume estimation of 5142 <span class="inline-formula">m<sup>3</sup></span> from the digital elevation model. The physical processes, including rockfall, toppling, and complex motion behaviors of rock interacting with slope inferred from the spectrogram features were comprehensively supported by the video record and field investigation. We also demonstrated that the GeoLoc scheme, which has been implemented in Sinwulyu catchment, Taiwan, can provide fast reports, including the location, volume, and physical process of events, to the public soon after they occur.</p>https://esurf.copernicus.org/articles/9/505/2021/esurf-9-505-2021.pdf
spellingShingle J.-M. Chang
W.-A. Chao
W.-A. Chao
W.-A. Chao
H. Chen
H. Chen
Y.-T. Kuo
C.-M. Yang
Locating rock slope failures along highways and understanding their physical processes using seismic signals
Earth Surface Dynamics
title Locating rock slope failures along highways and understanding their physical processes using seismic signals
title_full Locating rock slope failures along highways and understanding their physical processes using seismic signals
title_fullStr Locating rock slope failures along highways and understanding their physical processes using seismic signals
title_full_unstemmed Locating rock slope failures along highways and understanding their physical processes using seismic signals
title_short Locating rock slope failures along highways and understanding their physical processes using seismic signals
title_sort locating rock slope failures along highways and understanding their physical processes using seismic signals
url https://esurf.copernicus.org/articles/9/505/2021/esurf-9-505-2021.pdf
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