Horizontal compressive stress regime on the northern Cascadia margin inferred from borehole breakouts.

Riedel, Michael , Malinverno, A., Wang, K., Goldberg, D. and Guerin, G. (2016) Horizontal compressive stress regime on the northern Cascadia margin inferred from borehole breakouts. Open Access Geochemistry, Geophysics, Geosystems, 17 (9). pp. 3529-3545. DOI 10.1002/2016GC006443.

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Abstract

During Integrated Ocean Drilling Program Expedition 311 five boreholes were drilled across the accretionary prism of the northern Cascadia subduction zone. Logging-while-drilling borehole images are utilized to determine breakout orientations to define maximum horizontal compressive stress orientations. Additionally, wireline logging data at two of these sites and from Site 889 of Ocean Drilling Program Leg 146 are used to define breakouts from differences in the aperture of caliper arms. At most sites, the maximum horizontal compressive stress SHmax is margin-normal, consistent with plate convergence. Deviations from this trend reflect local structural perturbations. Our results do not constrain stress magnitudes. If the margin-normal compressional stress is greater than the vertical stress, the margin-normal SHmax direction we observe may reflect current locking of a velocity-weakening shallow megathrust and thus potential for trench-breaching, tsunamigenic rupture in a future megathrust earthquake.

Document Type: Article
Additional Information: WOS:000386929500001
Keywords: Borehole breakouts; Cascadia margin; IODP Expedition 311
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1002/2016GC006443
ISSN: 1525-2027
Projects: IODP
Expeditions/Models/Experiments:
  • IODP Exp.311
Date Deposited: 19 Sep 2016 07:41
Last Modified: 01 Feb 2019 15:06
URI: http://oceanrep.geomar.de/id/eprint/33831

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