Earthquakes in the Pamplona zone, Yakutat block, south central Alaska

Doser, Diane I.; Pelton, John R.; Veilleux, Annette M.

doi:10.1029/97jb01729

Cited by 28 publications

(21 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Three main foci of seismicity (Fig. 1A) help defi ne the plate kinematics: (1) thrust events along the eastern edge of the Pamplona zone (Doser et al, 1997), (2) thrust events at the eastern end of the Transition fault (Doser and Lomas, 2000), and (3) dextral strike-slip events along the Gulf of Alaska shear zone within the Pacifi c plate (Pegler and Das, 1996). We suggest a tectonic model of the plate boundaries (Fig.…”

Section: Discussionmentioning

confidence: 88%

Geophysical insights into the Transition fault debate: Propagating strike slip in response to stalling Yakutat block subduction in the Gulf of Alaska

Gulick

Lowe

Pavlis

et al. 2007

Geol

112

View full text Add to dashboard Cite

On the basis of faulting mapped on seismic refl ection and bathymetric data, seismicity, current plate motions, and evidence that the Yakutat block may be anomalously thick, we propose a tectonic model for Yakutat-Pacifi c interactions, including the often-debated Transition fault. To the east, deformation associated with the Queen Charlotte-Fairweather fault system is extending offshore, facilitating westward propagation of strike-slip motion along the eastern segment of the Transition fault. To the west, the oblique-slip Pamplona zone and Transition faults merge at an embayment in the continental margin, where a north-south dextral strikeslip fault within the Pacifi c plate, illuminated by the 1987-1992 earthquake swarm, intersects the Pacifi c-Yakutat tectonic boundary. These fault patterns are consistent with modern plate motions and refl ect a plate boundary reorganization that may be caused by resistance to subduction by the Yakutat block, a possible moderate-sized oceanic plateau.

show abstract

Section: Discussionmentioning

confidence: 88%

Geophysical insights into the Transition fault debate: Propagating strike slip in response to stalling Yakutat block subduction in the Gulf of Alaska

Gulick

Lowe

Pavlis

et al. 2007

Geol

112

View full text Add to dashboard Cite

show abstract

“…[] (1979 event), Doser et al . [] (1958 and 1970 events), Pegler and Das [] (1987–1992 Gulf of Alaska sequence), and U.S. Geological Survey/National Earthquake Information Center (2012 Gulf of Alaska event). BG is the Bering Glacier, PZ is the Pamplona Zone, and MG is the Malaspina Glacier.…”

Section: Tectonic Settingmentioning

confidence: 97%

“…The Pamplona zone was also the locus of an M 6.7 earthquake in 1970. This event was preceded and followed by several M 5–6 earthquakes with predominately N‐NW dipping thrust mechanisms [ Doser et al ., ]. At the end of February 1979, an M w 7.4 earthquake occurred northwest of Mount St. Elias.…”

Section: Tectonic Settingmentioning

confidence: 99%

Active tectonics of the St. Elias orogen, Alaska, observed with GPS measurements

2013

View full text Add to dashboard Cite

[1] We use data from campaign and continuous GPS sites in southeast and south central Alaska to constrain a regional tectonic block model for the St. Elias orogen. Active tectonic deformation in the orogen is dominated by the effects of the collision of the Yakutat block with southern Alaska. Our results indicate that~37 mm/yr of convergence is accommodated along a relatively narrow belt of N-NW dipping thrust faults in the eastern half of the orogen, with the present-day deformation front running through Icy Bay and beneath the Malaspina Glacier. Near the Bering Glacier, the collisional thrust fault regime transitions into a broad, northwest dipping décollement as the Yakutat block basement begins to subduct beneath the counterclockwise rotating Elias block. The location of this transition aligns with the Gulf of Alaska shear zone, implying that the Pacific plate is fragmenting in response to the Yakutat collision. Our model indicates that the Bering Glacier region is undergoing internal deformation and could correspond to the final stage of offscraping and accretion of sediments from the Yakutat block prior to subduction. Predicted block motions at the western edge of the orogen suggest that the crust is laterally escaping along the Aleutian fore arc.

show abstract

“…Early studies concentrated on attempts to use earthquake locations to delineate geometry of the subducting plate [ van Wormer et al , 1974; Stephens et al , 1984; Pulpan and Frohlich , 1985; Page et al , 1989]. Later seismicity studies worked on improving earthquake locations and providing better seismological constraints on tectonics of the region [ Estabrook et al , 1992; Doser et al , 1997; Ratchkovski et al , 1997, 1998; Doser et al , 1999; Doser and Lomas , 2000; Doser and Brown , 2001; Ratchkovski and Hansen , 2002]. A few tomographic studies used regional seismic data to constrain the extent and properties of the subducting plate [ Kisslinger and Lahr , 1991; Zhao et al , 1995; Searcy , 1996] and upper plate crust [ McNamara and Pasyanos , 2002].…”

Section: Previous Workmentioning

confidence: 99%

Imaging the transition from Aleutian subduction to Yakutat collision in central Alaska, with local earthquakes and active source data

Eberhart‐Phillips¹,

Christensen²,

Brocher³

et al. 2006

J. Geophys. Res.

299

520

View full text Add to dashboard Cite

[1] In southern and central Alaska the subduction and active volcanism of the Aleutian subduction zone give way to a broad plate boundary zone with mountain building and strike-slip faulting, where the Yakutat terrane joins the subducting Pacific plate. The interplay of these tectonic elements can be best understood by considering the entire region in three dimensions. We image three-dimensional seismic velocity using abundant local earthquakes, supplemented by active source data. Crustal low-velocity correlates with basins. The Denali fault zone is a dominant feature with a change in crustal thickness across the fault. A relatively high-velocity subducted slab and a low-velocity mantle wedge are observed, and high V p /V s beneath the active volcanic systems, which indicates focusing of partial melt. North of Cook Inlet, the subducted Yakutat slab is characterized by a thick low-velocity, high-V p /V s crust. High-velocity material above the Yakutat slab may represent a residual older slab, which inhibits vertical flow of Yakutat subduction fluids. Alternate lateral flow allows Yakutat subduction fluids to contribute to Cook Inlet volcanism and the Wrangell volcanic field. The apparent northeast edge of the subducted Yakutat slab is southwest of the Wrangell volcanics, which have adakitic composition consistent with melting of this Yakutat slab edge. In the mantle, the Yakutat slab is subducting with the Pacific plate, while at shallower depths the Yakutat slab overthrusts the shallow Pacific plate along the Transition fault. This region of crustal doubling within the shallow slab is associated with extremely strong plate coupling and the primary asperity of the M w 9.2 great 1964 earthquake.

show abstract

Earthquakes in the Pamplona zone, Yakutat block, south central Alaska

Cited by 28 publications

References 19 publications

Geophysical insights into the Transition fault debate: Propagating strike slip in response to stalling Yakutat block subduction in the Gulf of Alaska

Geophysical insights into the Transition fault debate: Propagating strike slip in response to stalling Yakutat block subduction in the Gulf of Alaska

Active tectonics of the St. Elias orogen, Alaska, observed with GPS measurements

Imaging the transition from Aleutian subduction to Yakutat collision in central Alaska, with local earthquakes and active source data

Contact Info

Product

Resources

About