1) Overview
This page gathers information on
earthquake characteristics
(through the SCARDEC method, see below) and on
GEOSCOPE data
available for these events: The “data” tab provides access to the data seed file (20000s window starting at the earthquake origin time), provides access to the theoretical arrival times, shows earthquake waveforms for each station and channel, and presents the global Earth wave propagation through the visualization of the LHZ channel. The “mechanism” tab illustrates the geometry of the movement during the earthquake, along the two possible faults planes determined by SCARDEC analysis.
Several e-mail alerts are available, as soon as a new earthquake has been analyzed: (1) for all earthquakes, (2) for earthquakes with Mw>=6.5, and (3) for earthquakes with Mw>=7. Please contact Martin Vallee (
vallee@ipgp.fr
) to be added in one of these mailing lists.
2) Analysis of the earthquake source (SCARDEC method)
SCARDEC method uses the teleseismic body waves to retrieve the
depth, focal mechanism, moment magnitude and source time function of earthquakes with magnitudes larger than 5.5-6
. Details of the methodology are described in
Vallee
et al. [2011] and an application to all earthquakes with magnitude larger than 6 in the period 1992-2011 can be found in
Vallee
[2013]. The consolidated SCARDEC catalog, with full access to earthquake parameters and source time functions, can be found
here
.
In the near-real time configuration presented here, the solution is typically posted
45 minutes after earthquake occurrence
. Solution includes a map summing up the SCARDEC results and a figure showing the agreement to the data. The map presents the earthquake location (together with the plate boundaries from
Bird
[2003] and the slab contours of SLAB 1.0 [
Hayes et al.
, 2012]) and the main SCARDEC source parameters. Numerical values of focal mechanism parameters and seismic moment are written below the map. The data agreement figure compares the SCARDEC synthetics (red) with the FDSN data (black), in the frequency range used for focal mechanism determination. The name of GEOSCOPE stations is written in green.
See more information (about the data, the procedure, the reasons that could prevent from providing the earthquake information, the source time function determination...) in
the "detailed notes"
.
If using some of the SCARDEC results, please refer to:
(1) Vallee, M., J. Charlety, A.M.G. Ferreira, B. Delouis, and J. Vergoz, SCARDEC : a new technique for the rapid determination of seismic moment magnitude, focal mechanism and source time functions for large earthquakes using body wave deconvolution, Geophys. J. Int., 184, 338-358, 2011.
(2) Vallee, M., Source time function properties indicate a strain drop independent of earthquake depth and magnitude, Nature Communications, doi: 10.1038/ncomms3606, 2013.
The method is running and maintained at
IPGP
laboratory. Apart from IPGP, past and present support to the development of the method are/were provided by the following institutes/projects :
We are grateful to the organisms providing, managing or federating data:
is used for drawing some maps of the webpage.