MOWLAS: NIED observation network for earthquake, tsunami and volcano

Aoi, Shin; Asano, Youichi; Kunugi, Taiseki; Kimura, Takeshi; Uehira, Kenji; Takahashi, Narumi; Ueda, Hitoshi; Shiomi, Katsuhiko; Matsumoto, Takumi; Fujiwara, Hiroyuki

doi:10.1186/s40623-020-01250-x

Cited by 185 publications

(139 citation statements)

References 121 publications

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“…Despite these scientific efforts, there is still a high level of uncertainty and low level of accuracy in the estimation of tsunami hazards 58 . Nowadays, the acquisition of the sea level variation in real-time at the earthquake source is only available for submarine sensors networks 59 , 60 (e.g., DONET in Japan and NEPTUNE in Canada). In the analyzed area, Chile has an extensive real-time tide gauges network that provides quality information of tsunami coastal propagation.…”

Section: Discussionmentioning

confidence: 99%

Tsunami detection by GPS-derived ionospheric total electron content

Shrivastava

Maurya

González

et al. 2021

Sci Rep

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To unravel the relationship between earthquake and tsunami using ionospheric total electron content (TEC) changes, we analyzed two Chilean tsunamigenic subduction earthquakes: the 2014 Pisagua Mw 8.1 and the 2015 Illapel Mw 8.3. During the Pisagua earthquake, the TEC changes were detected at the GPS sites located to the north and south of the earthquake epicenter, whereas during the Illapel earthquake, we registered the changes only in the northward direction. Tide-gauge sites mimicked the propagation direction of tsunami waves similar to the TEC change pattern during both earthquakes. The TEC changes were represented by three signals. The initial weaker signal correlated well with Acoustic Rayleigh wave (AWRayleigh), while the following stronger perturbation was interpreted to be caused by Acoustic Gravity wave (AGWepi) and Internal Gravity wave (IGWtsuna) induced by earthquakes and subsequent tsunamis respectively. Inevitably, TEC changes can be utilized to evaluate earthquake occurrence and tsunami propagation within a framework of multi-parameter early warning systems.

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Section: Discussionmentioning

confidence: 99%

Tsunami detection by GPS-derived ionospheric total electron content

Shrivastava

Maurya

González

et al. 2021

Sci Rep

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“…Crustal deformation in Japan can be evaluated with abundant data from seismic and geodetic observation stations (Aoi et al 2020). The crust is affected by perturbations from volcanic and seismic activities (Ueda et al 2013) and surface loads (Heki 2004), including non-tidal ocean loading (Sato et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Spatial and temporal influence of rainfall on crustal pore pressure based on seismic velocity monitoring

Andajani

Tsuji

Snieder

et al. 2020

Earth Planets Space

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Crustal pore pressure, which controls the activities of earthquakes and volcanoes, varies in response to rainfall. The status of pore pressure can be inferred from observed changes in seismic velocity. In this study, we investigate the response of crustal pore pressure to rainfall in southwestern Japan based on time series of seismic velocity derived from ambient noise seismic interferometry. To consider the heterogeneity of the area, rainfall and seismic velocity obtained at each location were directly compared. We used a band-pass filter to distinguish the rainfall variability from sea level and atmospheric pressure, and then calculated the cross-correlation between rainfall and variations in S-wave velocity (Vs). A mostly negative correlation between rainfall and Vs changes indicates groundwater recharge by rainfall, which increases pore pressure. The correlations differ between locations, where most of the observation stations with clear negative cross-correlations were located in areas of granite. On the other hand, we could not observe clear correlations in steep mountain areas, possibly because water flows through river without percolation. This finding suggests that geographical features contribute to the imprint of rainfall on deep formation pore pressure. We further modelled pore pressure change due to rainfall based on diffusion mechanism. A strong negative correlation between pore pressure estimated from rainfall and Vs indicates that the Vs variations are triggered by pore pressure diffusion in the deep formation. Our modelling results show a spatial variation of diffusion parameter which controls the pore pressure in deep formation. By linking the variations in seismic velocity and crustal pore pressure spatially, this study shows that seismic monitoring may be useful in evaluating earthquake triggering processes or volcanic activity.

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“…In this study, spacing varies between 50 and 200 km. This geometry recognizes the ambiguity of recorded signals from large numbers of interior shelf and slope nodes (Hilmo & Wilcock, 2020) as well as the economic infeasibility of such a task as in the Japanese dedicated early warning systems S-net, DONET, and N-net (Aoi et al, 2020).…”

Section: Earthquake and Tsunami Early Warning In Sumatramentioning

confidence: 99%