The Turkish Dilatancy Project (TDP3): multidisciplinary studies of a potential earthquake source region
Evans, Russ; Beamish, David; Crampin, Stuart; Ucer, S. Balamir. 1987 The Turkish Dilatancy Project (TDP3): multidisciplinary studies of a potential earthquake source region. Geophysical Journal of the Royal Astronomical Society, 91 (2). 265-286. 10.1111/j.1365-246X.1987.tb05227.x
Before downloading, please read NORA policies.Preview |
Text
NORA_1987_TDP_GJRAS.pdf - Accepted Version Download (1MB) | Preview |
Abstract/Summary
The section of the North Anatolian Fault lying near the city of Izmit, at the east of the Marmara Sea, has been identified as a seismic gap and the possible site of a future major earthquake. Previously published studies of records from an earthquake swarm within the gap (TDPl and TDP2) provided the first evidence that shear-wave splitting occurs in earthquake source regions, a conclusion since verified by many studies at other locations. A third field study (TDP3) was mounted in the Izmit region during the summer of 1984. Observations were made over an eight-month period and included geomagnetic and geoelectric measurements in addition to a series of observations utilising dense arrays of three-component seismometers. Earthquake activity in the principal study area was monitored over a period of eight months. Records showed features similar to those observed in the earlier studies. In particular: (1) almost all shear waves emerging within the shear-wave window displayed shear-wave splitting; (2)the polarizations of the first arriving (faster) split shear-waves showed sub-parallel alignments, characteristic of propagation through a distribution of parallel vertical cracks striking perpendicular to the minimum compressional stress. These and other observations support the conclusion of earlier studies - that the upper crust is pervaded by distributions of micro cracks aligned by stress, known as extensive-dilatancy anisotropy. A search for time dependence in shear-wave phenomena has revealed temporal variations in the delays between the split shear-waves throughout the course of the TDP3 study, but as yet this has not been correlated wi th specific earthquake activity.
Item Type: | Publication - Article |
---|---|
Digital Object Identifier (DOI): | 10.1111/j.1365-246X.1987.tb05227.x |
Programmes: | BGS Programmes > Seismology and Geomagnetism |
NORA Subject Terms: | Earth Sciences |
Date made live: | 18 Apr 2016 11:48 +0 (UTC) |
URI: | https://nora.nerc.ac.uk/id/eprint/513460 |
Actions (login required)
View Item |
Document Downloads
Downloads for past 30 days
Downloads per month over past year