Broadband body waves recorded at 15 digital seismic stations worldwide are used to study the rupture process of the May 23, 1989 Macquarie Ridge earthquake. The centroidal solution (strike 211°, dip 86°, rake 180°, and depth of 10 km below the seafloor) indicates shallow rupture with pure right-lateral strike-slip motion...
Here we use SKS shear wave splitting observations from ocean-bottom seismometer data to infer patterns of mantle deformation beneath the Juan de Fuca plate and its adjoining boundaries. Our results indicate that the asthenosphere beneath the Juan de Fuca plate responds largely to absolute plate motion with an anisotropic layer...
From December 2006 to November 2011, the Pacific Northwest Seismic Network (PNSN)
reported 467 earthquakes in a swarm 60 km east of Mt Hood near the town of Maupin, Oregon.
The swarm included 20 M[subscript D] ≥ 3.0 events, which account for over 80 per cent of the cumulative
seismic...
Faults break under the stress of plate tectonic forces, but the processes immediately preceding rupture are enigmatic. Monitoring of a remote oceanic fault that breaks
regularly indicates that rupture is controlled by physical properties of the fault
zone.
Low-angle normal faulting is widely discussed as a possible mechanism for continental extension, however, unambiguous evidence for seismogenic low-angle normal faulting is lacking. Here, we investigate seismicity along a short segment of the Pumqu-Xianza Rift (PXR) in southern Tibet, where the HiCLIMB seismic array recorded over 500 earthquakes between 2004...
The Blanco Transform Fault Zone (BTFZ) forms the ~350 km long Pacific–Juan de
Fuca plate boundary between the Gorda and Juan de Fuca ridges. Nearby broadband seismic networks provide a unique framework for a detailed, long-term seismotectonic study of an entire oceanic transform fault (OTF) system. We use regional waveforms...
We use regional broadband seismograms to obtain
seismic moment-tensor solutions of the two September 20, 1993,
Mw =6, Klamath Falls, Oregon earthquakes, their foreshock and
largest aftershocks (MD>3.5). Several sub-groups with internally
consistent solutions indicate activity on several fault segments
and faults. From the estimated moment-tensors and depths of the...
The Explorer region offshore western Canada is a tectonically complex area
surrounded by the Pacific, North America, and Juan de Fuca plates. Existing tectonic
models for the region differ fundamentally. Proposed plate configurations range from
multiple independent plate fragments to an Explorer plate now fused to North America
along the...
Teleseismic body waves from large earthquakes are used to study the downdip
geometry of continental normal faults in the Aegean. Waveform modeling technique together with rigorous statistical tests are applied to put firm bounds on the amount of downdip curvature of these faults and the role of coseismic slip on...