Since November 30, 2020, an intense seismic swarm and transient deformation have been continuously observed in the Noto Peninsula, central Japan, which is a non-volcanic/geothermal area far from major plate boundaries. We modeled based on combined analysis of multiple Global Navigation Satellite System (GNSS) observation networks, including one operated by private sector company (SoftBank Corp.), relocated earthquake hypocenters, tectonic settings. Our showed total displacement pattern over...

Real‐time crustal deformation monitoring is extremely important for achieving rapid understanding of actual earthquake scales, because the measured permanent displacement directly gives true size (seismic moment, M w ) information, which in turn, provides tsunami forecasting. We have developed an algorithm to detect/estimate static ground displacements due faulting from real‐time kinematic GPS (RTK‐GPS) time series. The new identifies by difference a short‐term average (STA) long‐term (LTA)...

Seafloor displacements observed after the Tohoku earthquake place large constraints on assessing deformation process.

Abstract The 2024 M w 7.5 Noto Peninsula, Japan, earthquake was initiated within the source region of intense swarm activity. To reveal mainshock early process, we relocated hypocenters and found that many key phenomena, including initiation, foreshocks, earthquakes, deep aseismic slip, occurred at parts a previously unrecognized fault in intricate network. This is subparallel (several kilometers deeper) to known active fault, initiation foreshocks front 2‐year westward migration. location...

We investigated the crustal deformation associated with 2011 off Pacific coast of Tohoku Earthquake (M 9.0) that occurred on March 11, 2011, along plate boundary district, northeastern Japan, based dense GPS observation. Coseismic displacements due to this event were applied estimate causal interplate slip by means a geodetic inversion analysis. The major area is located around asperities 1981 Miyagi-oki 7.2) and 2003 Fukushima-oki 6.8) earthquakes maximum estimated as being up 35 m....

The Great Sumatran Fault system in Indonesia is a major right‐lateral trench‐parallel that can be divided into several segments, most of which have ruptured within the last century. This study focuses on northern portion fault contains 200‐km‐long segment has not experienced earthquake at least 170 years. In 2005, we established Aceh GPS Network for System (AGNeSS) across this segment. AGNeSS observes large displacements include significant postseismic deformation from recent megathrust...

A magnitude 7.3 foreshock occurred at the subducting Pacific plate interface on March 9, 2011, 51 h before 9.0 Tohoku earthquake off coast of Japan. We propose a coseismic and postseismic afterslip model event based global positioning system network ocean bottom pressure gauge sites. The estimated slip areas show complementary spatial distributions; distribution is located up‐dip for northward hypocenter earthquake. amount roughly consistent with that determined by repeating analysis carried...

Ocean-bottom pressure records obtained near the epicenter of 2011 Tohoku-Oki earthquake were examined to test whether was preceded by substantial precursory crustal deformation. The seafloor data enabled us search for small-scale preslip that would be difficult identify from terrestrial geodetic data. After treating reduce nontectonic fluctuations, we a time series vertical deformation in epicentral region with noise level 2–4 cm. No significant related detected period roughly day before...

Abstract The short‐period seismometer‐based magnitude saturation problem, especially for events with > 8, can be improved by a real‐time Global Navigation Satellite System (GNSS) positioning technique, which has enabled rapid estimation of finite fault model large earthquake without any saturation. A new modeling system based on the GNSS Earth Observation Network (GEONET) is developed and under experimental operation in Japan. In this paper, we present newly REGARD (the Real‐time GEONET...

Crustal deformation after the 2011 Tohoku earthquake illuminates complex interplay between transient mantle flow and afterslip.

The tsunami disasters that occurred in Indonesia, Chile, and Japan have inflicted serious casualties damaged social infrastructures. Tsunami forecasting systems are thus urgently required worldwide. We developed a real-time inundation forecast system can complete damage for coastal cities at the level of 10-m grid size less than 20 min. As simulation is vectorizable memory-intensive program, we incorporate NEC's vector supercomputer SX-ACE. In this paper, present an overview our system....

Abstract We have developed a new algorithm that improves near‐field tsunami forecasting based on offshore data soon after an earthquake by incorporating real‐time onshore Global Navigation Satellite System (GNSS) data. In our algorithm, called tFISH/RAPiD (tsunami Forecasting Inversion for initial sea‐Surface Height/Real‐time Automatic detection method Permanent Displacement), the sea surface height distribution estimated from rapidly acquired GNSS provides robust finite source size...

This paper reviews recent studies on methods of realtime forecasting for near-field tsunamis that use either offshore tsunami data or onshore global navigation satellite system (GNSS) data. Tsunami early warning systems coastal communities are vital because evacuation time before arrival is usually very short. We focus between the occurrence a tsunamigenic earthquake and first at coast – typically few tens minutes less after earthquake. Offshore measurement provides with direct information...

We present the initial results of rapid fault estimations for 2016 Kumamoto earthquake on April 16 (M j 7.3), and coseismic displacements caused by two large foreshocks that occurred 14 6.5) 15 6.4) from GEONET real-time analysis system (REGARD), which is based a Global Navigation Satellite System (GNSS) kinematic positioning technique. The finite-fault estimate w 6.85) was obtained within 1 min converged to M 6.96 5 origin time mainshock 7.3). shows right-lateral strike-slip along Futagawa...

Abstract Monitoring of crustal deformation provides essential information for seismology and volcanology. For such earth science fields other purposes, various Global Navigation Satellite System (GNSS) networks have been constructed at the national regional levels. In Japan, continuous nationwide GNSS network, Earth Observation Network (GEONET), is operated by Geospatial Information Authority Japan. Although GEONET has made a substantial contribution to research, large spacing sites makes it...

Abstract A large earthquake of M j 7.2 occurred on June 14, 2008, beneath the border between Iwate and Miyagi prefectures in northeastern Japan. We propose a simple rectangular fault model based dense GPS network, including continuous sites run by four agencies, to describe coseismic deformation. The displacements are estimated kinematic PPP (precise point positioning) analysis. Near hypocenter, colocated independent instruments (integrated accelerogram PPP) measure same displacement caused...

Using GPS data, we evaluate the volume change of magma reservoir associated with eruption Kirishima Shinmoe-dake volcano, southern Kyushu, Japan, in 2011. Because ground deformation around volcano is strongly affected not only by regional tectonic movement but also inflation Sakurajima located approximately 30–40 km to southwest, first eliminate these unwanted contributions from observed data extract signals volcano. Then, estimate source locations and before, during, after highest eruptive...

Abstract We examine seismic velocity changes due to the Earth tide by conducting cross‐correlation function (CCF) analyses of ambient noise recorded at a small array composed seven seismometers in northeastern Japan. calculate CCFs for dilatational and contractional episodes that are predicted from theoretical tidal volumetric strains. two highly correlated, but tiny differences found their phases. The phase explained −0.19 ± 0.06% 1–2 Hz, which interpreted be caused opening/closure cracks...

The subduction rate of an oceanic plate may accelerate after large earthquakes rupture the interplate coupling between and overriding continental plates. To better understand postseismic deformation processes in incoming plate, we directly measured displacement Pacific Plate near Japan Trench 2011 Tohoku-Oki earthquake using a GPS/acoustic technique over period 2 years (September 2012 to September 2014). was be 18.0 ± 4.5 cm yr−1 (N302.0°E) relative North American Plate, which is almost...

Abstract Using two‐dimensional finite element modeling, we reproduced the observed postseismic deformation of 2011 Tohoku‐Oki earthquake. Our model, which accounts for lithosphere‐asthenosphere boundary and weak zones beneath volcanoes, was able to reproduce small‐scale (<20 km) perturbations in by dense geodetic network, such as local subsidence around Quaternary volcanoes. The inverted afterslip has a peak at downdip limit main rupture region on subducting plate interface, consistent...