Development and application of an advanced ocean floor network system for megathrust earthquakes and tsunamis

Kaneda, Yasufumi; Kawaguchi, Katsuyoshi; Araki, Eiichiro; Matsumoto, Hiroyuki; Nakamura, Takeshi; Kamiya, Shinichiro; Ariyoshi, Keisuke; Hori, Takane; Baba, Toshitaka; Takahashi, Narumi

doi:10.1007/978-3-642-11374-1_25

Cited by 145 publications

(89 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We used ocean‐floor observation data from off the Kii Peninsula obtained by temporarily deployed broadband ocean‐bottom seismometers (BBOBSs; Sugioka et al, ) and by the permanent Dense Oceanfloor Network System for Earthquakes and Tsunamis (DONET1; Kaneda et al, ; Kawaguchi et al, ; Figure ). VLFE activity was observed in this region in 2009, 2015, and 2016 (Nakano et al, , ; Sugioka et al, ), and tremor activity was detected in 2018.…”

Section: Datamentioning

confidence: 99%

Event Size Distribution of Shallow Tectonic Tremor in the Nankai Trough

Yabe

Sugioka

Shinohara

et al. 2019

Geophysical Research Letters

View full text Add to dashboard Cite

Slow earthquake size distributions have been found to follow either a power law or an exponential law, depending on the data set. We investigated the size distribution of shallow tectonic tremor events along the Nankai trough, southwestern Japan, observed in 2009, 2015, 2016, and 2018 and estimated the seismic energy radiated during the events as a measure of event size. The obtained size distributions mostly followed a power law with a b value of about 1, but an exponential law also fits well the data of the largest events; this result indicates that the size distribution follows the Gutenberg‐Richter law with an exponential taper. If only the largest events were observed, an exponential size distribution would be obtained. This exponential taper could be attributed to a source fault limitation. Because the maximum event size differed among activity periods, the source fault size varied among them, although the source areas largely overlap.

show abstract

Section: Datamentioning

confidence: 99%

Event Size Distribution of Shallow Tectonic Tremor in the Nankai Trough

Yabe

Sugioka

Shinohara

et al. 2019

Geophysical Research Letters

View full text Add to dashboard Cite

show abstract

“…However, the recent development of seafloor observation networks equipped with ocean-bottom pressure gauges (OBPGs) such as DONET (Kaneda et al 2015;Kawaguchi et al 2015) and S-net (Uehira et al 2012;Kanazawa 2013) may lead to further applications of the monitoring method based on the displacement rate gradients. We may infer the relative vertical displacement rates in the seafloor observation networks from the OBPG records, even though the sensor drift of OBPGs makes the estimation of the absolute vertical displacement at each OBPG site difficult.…”

Section: T Iinumamentioning

confidence: 99%

Monitoring of the spatio-temporal change in the interplate coupling at northeastern Japan subduction zone based on the spatial gradients of surface velocity field

Iinuma

2017

Geophysical Journal International

View full text Add to dashboard Cite

S U M M A R YA monitoring method to grasp the spatio-temporal change in the interplate coupling in a subduction zone based on the spatial gradients of surface displacement rate fields is proposed. I estimated the spatio-temporal change in the interplate coupling along the plate boundary in northeastern (NE) Japan by applying the proposed method to the surface displacement rates based on global positioning system observations. The gradient of the surface velocities is calculated in each swath configured along the direction normal to the Japan Trench for time windows such as 0.5, 1, 2, 3 and 5 yr being shifted by one week during the period of 1997-2016. The gradient of the horizontal velocities is negative and has a large magnitude when the interplate coupling at the shallow part (less than approximately 50 km in depth) beneath the profile is strong, and the sign of the gradient of the vertical velocity is sensitive to the existence of the coupling at the deep part (greater than approximately 50 km in depth). The trench-parallel variation of the spatial gradients of a displacement rate field clearly corresponds to the trenchparallel variation of the amplitude of the interplate coupling on the plate interface, as well as the rupture areas of previous interplate earthquakes. Temporal changes in the trench-parallel variation of the spatial gradient of the displacement rate correspond to the strengthening or weakening of the interplate coupling. We can monitor the temporal change in the interplate coupling state by calculating the spatial gradients of the surface displacement rate field to some extent without performing inversion analyses with applying certain constraint conditions that sometimes cause over-and/or underestimation at areas of limited spatial resolution far from the observation network. The results of the calculation confirm known interplate events in the NE Japan subduction zone, such as the post-seismic slip of the 2003 M8.0 Tokachi-oki and 2005 M7.2 Miyagi-oki earthquakes and the recovery of the interplate coupling around the rupture area of the 1994 M7.6 Sanriku-Haruka-oki earthquake. The results also indicate the semi-periodic occurrence of slow slip events and the expansion of the area of slow slip events before the 2011 Tohoku-oki earthquake (M9.0) approaching the hypocentre of the Tohoku-oki earthquake.

show abstract

“…Deep-sea pressure gauges are operating at 63 stations, and GPS sea-surface buoys are operating at eight stations (Tsushima and Ohta 2014). The pressure gauges are connected to land via seafloor cables, which are operated by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) (Momma et al 1997;Kasaya et al 2009;Kaneda et al 2015), JMA (Isozaki et al 1980;Fujisawa et al 1986;Saito et al 2007), and NIED (Eguchi et al 1998). The GPS buoys are operated by the Port and Airport Research Institute (PARI) (Kawai et al 2013).…”

Section: Nankai Trough Great Earthquakementioning

confidence: 99%

“…Japan has the world's densest earthquake and tsunami observatories in both land and ocean (Okada et al 2004;Kanazawa 2013;Kaneda et al 2015). Rapid earthquake and tsunami warning and forecast systems are expected to work well for future great Nankai Trough and Japan Trench earthquakes and tsunamis .…”

Section: Summary and Remarksmentioning

confidence: 99%

Assessment of GNSS-based height data of multiple ships for measuring and forecasting great tsunamis

et al. 2016

View full text Add to dashboard Cite

Ship height positioning by the Global Navigation Satellite System (GNSS) was investigated for measuring and forecasting great tsunamis. We first examined GNSS height-positioning data of a navigating vessel. If we use the kinematic precise point positioning (PPP) method, tsunamis greater than 10 −1 m will be detected by ship height positioning. Based on Automatic Identification System (AIS) data, we found that tens of cargo ships and tankers are usually identified to navigate over the Nankai Trough, southwest Japan. We assumed that a future Nankai Trough great earthquake tsunami will be observed by the kinematic PPP height positioning of an AIS-derived ship distribution, and examined the tsunami forecast capability of the offshore tsunami measurements based on the PPP-based ship height. A method to estimate the initial tsunami height distribution using offshore tsunami observations was used for forecasting. Tsunami forecast tests were carried out using simulated tsunami data by the PPP-based ship height of 92 cargo ships/ tankers, and by currently operating deep-sea pressure and Global Positioning System (GPS) buoy observations at 71 stations over the Nankai Trough. The forecast capability using the PPP-based height of the 92 ships was shown to be comparable to or better than that using the operating offshore observatories at the 71 stations. We suppose that, immediately after the occurrence of a great earthquake, stations receiving successive ship information (AIS data) along certain areas of the coast would fail to acquire ship data due to strong ground shaking, especially near the epicenter. Such a situation would significantly deteriorate the tsunami-forecast capability using ship data. On the other hand, operational real-time analysis of seismic/geodetic data would be carried out for estimating a tsunamigenic fault model. Incorporating the seismic/geodetic fault model estimation into the tsunami forecast above possibly compensates for the deteriorated forecast capability.

show abstract

Development and application of an advanced ocean floor network system for megathrust earthquakes and tsunamis

Cited by 145 publications

References 0 publications

Event Size Distribution of Shallow Tectonic Tremor in the Nankai Trough

Event Size Distribution of Shallow Tectonic Tremor in the Nankai Trough

Monitoring of the spatio-temporal change in the interplate coupling at northeastern Japan subduction zone based on the spatial gradients of surface velocity field

Assessment of GNSS-based height data of multiple ships for measuring and forecasting great tsunamis

Contact Info

Product

Resources

About