GRiD MT

Introduction A possibility of realtime monitoring of long-period seismic wavefield for simultaneous determination of moment tensor and centroid location was suggested by Kawakatsu (1998).    In JAPAN, Japanese university seismographic Network were constructed by satellite communication system so called VSAT. The packet format is so called WIN FORMAT and now became the most popular recording and transfer format in JAPAN.    Using such realtime waveform data (long-period > 10sec), this system (GRiD MT) automatically determines Momement Tensors every one second at all virtual sources. RealTime Monitoring We perform realtime monitoring for a mesh size of 25 x 25 x 11 (240km x 240km x 90km volume), We take the horizontal and vertical grid size of 10km and 9km, respectively. Movie Demo NEW Readme This page consists of three parts. Monitoring page This page is updated normally every 10 minutes. Events in this page are the best solutions (=MAX Variance Reduction (VR)) of each 10-minutes time window. Most events are unlikely to be real earthquakes. When VR is greater than 65%, however, they are most likely real earthquakes. Triggered event page Triggered event (VR.ge.65) is automatically listed. Event list page Triggered events (VR.ge.50) are checked manually and listed (this page will be eventually automated as well).

Monitoring Regions

Go To Monitoring Page --> IBARAKI-OKI --> IBARAKI-OKI[TSK,YMZ] --> NORTH IBARAKI --> CHIBA-IBARAKI --> TOKAI-OKI --> SHIZUOKA --> NIIGATA-NAGANO --> SANRIKU-OKI --> SANRIKU-OKI(EAST) --> SANRIKU-OKI[YMZ,GJM,TMR] --> TOKACHI-OKI --> DLFT/ESS(1) --> DLFT/ESS(2) o Latest Triggered Event VR>=65

Go To Triggerd Event Page 2023 VR>=65.0 --> IBARAKI-OKI --> IBARAKI-OKI[YMZ,TSK] --> NORTH IBARAKI --> CHIBA-IBARAKI --> TOKAI-OKI --> SHIZUOKA --> NIIGATA-NAGANO --> SANRIKU-OKI --> SANRIKU-OKI(EAST) --> SANRIKU-OKI[YMZ,GJM,TMR] --> TOKACHI-OKI --> DLFT/ESS(1) --> DLFT/ESS(2) --> ALL REGION

Go To Event List 2023 --> ALL REGION

[ 2003 result ] [ 2004 result ] [ 2005 result ] [ 2006 result ] [ 2007 result ] [ 2008 result ] [ 2009 result ] [ 2010 result ]

References

• Kawakatsu, H., (1998) On the realtime monitoring of the long-period seismic wavefield., Bull. Earth. Res. Inst., 73, 267-274.
• Kawakatsu, H. (2002), On the realtime monitoring of the long-period seismic wavefield, in Methods and applications of signal processing in seismic network operations, edited by T. Takanami and G. Kitagawa, Springer, 266pp, 251-257. (reprint of Kawakatsu (1998)).
• Tsuruoka, H., et al., (2001) Feasibility test for realtime continuous monitoring of long-period seismic wave field., AGU 2001, S11B-0567.
• Tsuruoka, H., et al., GRiD MT (Grid-based Realtime Determination of Moment Tensors) monitoring the long-period seismic wavefield , Phys. Earth Planet. Int., Special issue: Earthquakes in subduction zones: A multidisciplinary approach, 175, 8-16, 2009.
• Kawakatsu, H., J.-P. Montagner (2008), Time-reversal seismic-source imaging and moment-tensor inversion, Geophy. J. Int., 175. 686-688, 2008.

LINK

• JOHO
• Hi-net
• F-net
• OLD GRiD MT Page

ACKNOWLEDGEMENT

We use the broadband data recorded in the F-net networks operated by National Research Institute for Earth Science and Disaster Prevention.