On the CTBT Monitoring Potential of Using LG-Phase Arrival Times at Local and Regional Distance Ranges

The prominent Lg wave is nearly always observed at local and regional distances. It is a surface wave propagating with almost constant group velocity around 3.5 km/s over a vast distance range of hundreds to thousands of kilometers. Thus, Lg propagation should in principle simplify epicenter locatio...

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Bibliographic Details
Main Authors: Pinsky, Vladimir I., Husebye, Eystein S., Matveeva, Tatiana S., Fedorenko, Yury V.
Other Authors: GEOPHYSICAL INST OF ISRAEL HOLON (ISRAEL)
Format: Text
Language:English
Published: 2008
Subjects:
Test Facilities
Equipment and Methods
Target Direction
Range and Position Finding
*MONITORING
*ARRIVAL
*RANGE(DISTANCE)
*PHASE
SYMPOSIA
SURFACE WAVES
PROBABILITY
TIME
GROUP VELOCITY
BEAM FORMING
GROUND BASED
EQUATIONS
EPICENTERS
HILBERT SPACE
PROPAGATION
NUCLEAR EXPLOSIONS
BALTIC SEA
ALGORITHMS
ISRAEL
*ARRIVAL TIME
FOREIGN REPORTS
Apatity
Bergen
Norway
Fennoscandia
Online Access:http://www.dtic.mil/docs/citations/ADA516244
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA516244
Description
Summary:The prominent Lg wave is nearly always observed at local and regional distances. It is a surface wave propagating with almost constant group velocity around 3.5 km/s over a vast distance range of hundreds to thousands of kilometers. Thus, Lg propagation should in principle simplify epicenter location schemes, based on relative travel time equations. In our ongoing efforts to accomplish this we computed Hilbert or STA-envelopes and showed that in many recordings from Fennoscandia and Central Europe the Lg group velocities measured using the envelope peak arrival times are remarkably consistent. However, they tightly concentrate around 3.4 km/sec for the Baltic shield of Fennoscandia and around 3.2 km/sec for the much younger crust of Central Europe. These Lg picks were subsequently used in the Pinsky (2008) relative time location algorithms of "group beamforming" and "probabilistic beamforming" for refined epicenter locations in Balticum. Presented at the Conference on Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies (30th), held in Portsmouth, VA, on 23-25 Sep 2008. Published in the proceedings of the conference, p435-444, 2008. Prepared in collaboration with Bergen Center of Computational Science, UNIFOB/UoBergen, Norway, and the Polar Geophysical Institute, Apatity, Russia. Sponsored in part by the National Nuclear Security Administration (NNSA) and the Bergen Center of Computational Science. The original document contains color images.

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