A seismological study of landquakes using a real-time broad-band seismic network

Chen, Chi Hsuan; Chao, Wei An; Wu, Yih‐Min; Zhao, Li; Chen, Yue‐Gau; Ho, Wan Yun; Lin, Tsair-Fuh; Kuo, Kuan Hung; Chang, Jui Ming

doi:10.1093/gji/ggt121

Cited by 61 publications

(79 citation statements)

References 37 publications

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“…Dynam. These events lasted between a few seconds and a minute and have characteristics such as emergent onsets, slowly decaying 5 tails, and triangularly shaped spectrograms that have been described elsewhere from slope failures (Dammeier et al, 2011;Burtin et al, 2013;Chen et al, 2013). We attribute these signals to smaller slope failures that occurred after the main landslide.…”

Section: Tremor Modellingmentioning

confidence: 62%

Dynamics of the Askja caldera July 2014 landslide, Iceland, from seismic signal analysis: precursor, motion and aftermath

Schöpa¹,

Chao²,

Lipovsky³

et al. 2017

Preprint

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Abstract. Using data from a network of 58 seismic stations, we characterise a large landslide that occurred at the southeastern corner of the Askja caldera, Iceland, on 21 July 2014, including its precursory tremor and mass wasting aftermath. Our study is motivated by the need for deeper generic understanding of the processes operating not only at the time of catastrophic slope failure, but also in the preparatory phase and during the transient into the subsequent stable state.In addition, it is prompted by the high hazard potential of the steep caldera lake walls at Askja as tsunami waves created by 15 the landslide reached famous tourist spots 60 m above the lake level. Since direct observations of the event are lacking, the seismic data give valuable details on the dynamics of this landslide episode. The excellent seismic data quality and coverage of the stations of the Askja network made it possible to jointly analyse the long-and short-period signals of the landslide to obtain information about the triggering, initiation, timing, and propagation of the slide. The seismic signal analysis and a landslide force history inversion of the long-period seismic signals showed that the Askja landslide was a single, large event 20starting at the SE corner of the caldera lake at 23:24:05 UTC and propagating to the NW in the following 2 min. The bulk sliding mass was 7-16×10 10 kg, equivalent to a collapsed volume of 35-80×10 6 m 3 , and the centre of mass was displaced horizontally downslope by 1260±250 m during landsliding. The seismic records of stations up to 30 km away from the landslide source area show a tremor signal that started 30 min before the main landslide failure. It is harmonic, with a fundamental frequency of 2.5 Hz and shows time-dependent changes of its frequency content. We attribute the complex 25 tremor signal to accelerating and decelerating stick-slip motion on failure planes at the base and the sides of the landslide body. The accelerating motion culminated in aseismic slip of the landslide visible as a drop in the seismic amplitudes down to the background noise level 2 min before the landslide high-energy signal begins. We propose that the seismic signal of the precursory tremor may be developed as an indicator for landslide early-warning systems. The 8 hours after the main landslide failure are characterised by smaller slope failures originating from the destabilised caldera wall decaying in 30 frequency and magnitude. We introduce the term afterslides for this subsequent, declining slope activity after a large landslide.Earth Surf. Dynam. Discuss., https://doi

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Section: Tremor Modellingmentioning

confidence: 62%

Dynamics of the Askja caldera July 2014 landslide, Iceland, from seismic signal analysis: precursor, motion and aftermath

Schöpa¹,

Chao²,

Lipovsky³

et al. 2017

Preprint

Self Cite

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“…Hence, this allows a seismic detection of the events that do not generate long-period seismic waves (e.g. Deparis et al, 2008;Helmstetter and Garambois, 2010;Dammeier et al, 2011Dammeier et al, , 2016Hibert et al, 2011Hibert et al, , 2014bClouard et al, 2013;Chen et al, 2013;Burtin et al, 2013;Tripolitsiotis et al, 2015;Zimmer and Sitar, 2015). The limitation of this approach is that high-frequency seismic waves are more prone to be influenced by propagation effects (attenuation, dispersion, scattering) and, more importantly, that the source of the high-frequency seismic waves associated with gravitational instabilities is not yet well understood.…”

Section: As Well As Theirmentioning

confidence: 99%

Single-block rockfall dynamics inferred from seismic signal analysis

et al. 2017

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Abstract. Seismic monitoring of mass movements can significantly help to mitigate the associated hazards; however, the link between event dynamics and the seismic signals generated is not completely understood. To better understand these relationships, we conducted controlled releases of single blocks within a soft-rock (black marls) gully of the Rioux-Bourdoux torrent (French Alps). A total of 28 blocks, with masses ranging from 76 to 472 kg, were used for the experiment. An instrumentation combining video cameras and seismometers was deployed along the travelled path. The video cameras allow reconstructing the trajectories of the blocks and estimating their velocities at the time of the different impacts with the slope. These data are compared to the recorded seismic signals. As the distance between the falling block and the seismic sensors at the time of each impact is known, we were able to determine the associated seismic signal amplitude corrected for propagation and attenuation effects. We compared the velocity, the potential energy lost, the kinetic energy and the momentum of the block at each impact to the true amplitude and the radiated seismic energy. Our results suggest that the amplitude of the seismic signal is correlated to the momentum of the block at the impact. We also found relationships between the potential energy lost, the kinetic energy and the seismic energy radiated by the impacts. Thanks to these relationships, we were able to retrieve the mass and the velocity before impact of each block directly from the seismic signal. Despite high uncertainties, the values found are close to the true values of the masses and the velocities of the blocks. These relationships allow for gaining a better understanding of the physical processes that control the source of high-frequency seismic signals generated by rockfalls.

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“…For comparison, similar evaluations resulted in E = 150 TJ, µ = 0.12, v = 298 km h −1 , and V = 10 7 m 3 for the 2009 Hsiaolin landslide in Taiwan (Lin et al, 2010Lin, 2015), and E = 55 TJ, v = 101 km h −1 and V = 2.1 × 10 7 m 3 for the 2011 Atakani landslide in Japan (Yamada et al, 2013). Systematic evaluations of landslide characteristics based on seismic recordings are also given by Chen et al (2013).…”

Section: Open Discussion: the Lesson Of A Killer Landslidementioning

confidence: 94%

“…In fact, it is known that landslides generate seismic signals, "landquakes", which contain a specific signature: low-frequency waves released by the bedrock when the mass detaches, and high-frequency waves produced by the landslide mass while it is sliding, peaking when it impacts the deposition area (e.g. Yamada et al, 2012;Chen et al, 2013). If analysed separately, they can give information on both landslide initiation and impact (Fig.…”

Section: Open Discussion: the Lesson Of A Killer Landslidementioning

confidence: 99%

Brief communication: Post-seismic landslides, the tough lesson of a catastrophe

Fan

Scaringi

2018

Nat. Hazards Earth Syst. Sci.

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Abstract. The rock avalanche that destroyed the village of Xinmo in Sichuan, China, on 24 June 2017, brought the issue of landslide risk and disaster chain management in highly seismic regions back into the spotlight. The long-term postseismic behaviour of mountain slopes is complex and hardly predictable. Nevertheless, the integrated use of field monitoring, remote sensing and real-time predictive modelling can help to set up effective early warning systems, provide timely alarms, optimize rescue operations, and perform secondary hazard assessments. We believe that a comprehensive discussion on post-seismic slope stability and on its implications for policy makers can no longer be postponed.

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A seismological study of landquakes using a real-time broad-band seismic network

Cited by 61 publications

References 37 publications

Dynamics of the Askja caldera July 2014 landslide, Iceland, from seismic signal analysis: precursor, motion and aftermath

Dynamics of the Askja caldera July 2014 landslide, Iceland, from seismic signal analysis: precursor, motion and aftermath

Single-block rockfall dynamics inferred from seismic signal analysis

Brief communication: Post-seismic landslides, the tough lesson of a catastrophe

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