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...
New analyses of teleseismic body waves from moderate earthquakes in western Argentina demonstrate that active shortening of the Andean foreland occurs on reverse faults extending to 40–50 km depth. Existing crustal‐scale models of foreland deformation invoke thin‐skinned fault geometries, which root into an east‐dipping mid‐crustal décollement. Whereas thin‐skinned thrust sheets...
In this paper we outline a procedure we use for routine moment-tensor analysis of regional data from broadband seismic stations in northwestern North America and apply it to the moment magnitude 5.5, March, 1993, Scotts Mills, Oregon, earthquake. The results compare favorably with those obtained from teleseismic data. We found...
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...
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...
The actively subsiding North China sedimentary basin is associated with an unusually high level of seismic activity. This oil- and gas-producing basin has been the site of nine large (M ≥ 7), destructive earthquakes since 1600 A. D. An analysis of faulting during the Tangshan earthquake sequence, which includes some...
The fault plane orientation of the July 30, 1967, Caracas earthquake (Mw=6.6) has been a source of controversy for several years. This strike-slip event was originally thought to have occurred on an east-west oriented fault plane, reflecting the relative motion between the Caribbean and South American plates. More recently, however,...
The 1994 Northridge and 1987 Whittier Narrows earthquakes warned Los Angeles residents of the threat of earthquakes due to unmapped, blind reverse faults and emphasized the importance of identifying and characterizing blind reverse faults in assessing the seismic hazard to the region. The East and West Coyote Hills in the...
Measuring surface heat flow at the Hikurangi Trough is key toward characterizing the local thermal regime and the influence of thermally sensitive processes such as fluid flow and slow slip. Marine heat flow data were collected during May– June 2015 in the northern Hikurangi Trough at sites seaward and landward...
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...