Effect of pressure on 3D distribution of P-wave velocity and attenuation in antigorite serpentinite

0475899 - GLÚ 2018 RIV US eng J - Článek v odborném periodiku
Svitek, Tomáš - Vavryčuk, Václav - Lokajíček, Tomáš - Petružálek, Matěj - Kern, H.
Effect of pressure on 3D distribution of P-wave velocity and attenuation in antigorite serpentinite.
Geophysics. Roč. 82, č. 4 (2017), WA33-WA43. ISSN 0016-8033. E-ISSN 1942-2156
Grant CEP: GA ČR GA13-13967S; GA ČR(CZ) GA16-03950S; GA ČR(CZ) GC16-19751J
Institucionální podpora: RVO:67985831 ; RVO:67985530
Klíčová slova: antigorite * serpentinite * P-wawe velocity
Obor OECD: Geology; Geology (GFU-E)
Impakt faktor: 2.368, rok: 2017

We have developed a detailed study on the pressure dependence of P-wave velocities and amplitudes on a spherical sample of antigorite serpentinite from Val Malenco, Northern Italy. Measurements were done at room temperature and hydrostatic pressures up to 400 MPa in a pressure vessel with oil as a pressure medium. The transducer/sample assembly allows simultaneous velocity and amplitude measurements on the spherical sample in 132 independent directions.
Three significant directions of the foliated sample were selected to study changes of the directional dependence (anisotropy) of velocity, amplitude, and Q-factor with increasing pressure. Remarkable differences are observed between the changes of velocity and attenuation anisotropy as pressure is increased. Although the velocity anisotropy is quite stable through all pressure levels, the attenuation anisotropy and the Q-factor vary significantly in magnitude and orientation. The variations are probably caused by the closing of microcracks due to acting hydrostatic pressure, so the contact conditions between individual minerals consolidate
and the transmitting energy is less attenuating.
Trvalý link: http://hdl.handle.net/11104/0272615