Grid-based RealtIme Determination of Moment Tensors

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.

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 2015
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 2015

--> ALL REGION
[ 2003 result ] [ 2004 result ] [ 2005 result ] [ 2006 result ] [ 2007 result ] [ 2008 result ] [ 2009 result ] [ 2010 result ]

References

LINK

ACKNOWLEDGEMENT

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

tsuru@eri.u-tokyo.ac.jp