Untitled

McCalpin, James P.

doi:10.1130/ges00594.1

Cited by 25 publications

(10 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At an even larger scale, Bauer et al (2014) analyze the entire orogen from passive seismic imaging. In contrast, McCalpin et al (2011) and Headley et al (2013) are more focused studies of active deformation and glacial erosion, respectively, affecting the surface and upper crust.…”

Section: Themed Issue Contentsmentioning

confidence: 89%

“…The origin of these surface ruptures has been controversial because, although Carver and McCalpin (1996) described many of these ruptures as fl exural slip scarps related to active folding, they are spatially associated with ridge tops, they seem too numerous for active faults unless deformation rates are very high, and at least some of the ruptures had been clearly associated with gravity collapse sackung (Bruhn et al, 2004;Li et al, 2010). McCalpin et al (2011) carefully document a series of these surface ruptures, including trenching studies of several of the scarps as well as geomorphic analyses of local scarp arrays, and conclude that the system is a mix of gravity driven spreading structures and tectonic scarps with gravity structures including sackung and bedding-plane toppling scarps. An eastnortheast-trending oblique-normal fault system was recognized within the area as an active fault system with slip clarifi ed by both geomorphology and slickenlines on a trenched fault surface.…”

Section: Themed Issue Contentsmentioning

confidence: 98%

“…The study by McCalpin et al (2011) considers the active tectonics of the western part of the St. Elias orogen through an analysis of surface ruptures. This area, between the Bering Glacier and Copper River, has long been a puzzle in the local geology because it is characterized by swarms of surface ruptures.…”

Section: Themed Issue Contentsmentioning

confidence: 99%

See 2 more Smart Citations

Introduction: Neogene tectonics and climate-tectonic interactions in the southern Alaskan orogen themed issue

et al. 2014

View full text Add to dashboard Cite

Section: Themed Issue Contentsmentioning

confidence: 89%

Section: Themed Issue Contentsmentioning

confidence: 98%

See 1 more Smart Citation

Introduction: Neogene tectonics and climate-tectonic interactions in the southern Alaskan orogen themed issue

et al. 2014

View full text Add to dashboard Cite

“…The accreted terrain is partly indented into the plate margin, but it is also escaping toward the southwest over the northeastern part of the Aleutian megathrust Pavlis et al, 2004;Elliott, 2011). Geological evidence for active deformation includes sinistral faulting on oblique-slip faults McCalpin et al, 2011), thrust faulting Chapman et al, 2012), and structural reactivation of a deformed remnant of the Chugach-Saint Elias suture (Fig. 2;Bruhn et al, 2004).…”

Section: Tectonic Setting Of the Yakutat Blockmentioning

confidence: 99%

“…2;Bruhn et al, 2004). Antislope fault scarps and landslides in mountain blocks attest to the instability of the steep and recently deglaciated slopes (e.g., Li et al, 2010;McCalpin et al, 2011).…”

Section: Tectonic Setting Of the Yakutat Blockmentioning

confidence: 99%

Untitled

et al. 2012

View full text Add to dashboard Cite

Structural syntaxes, tectonic aneurysms, and fault-bounded fore-arc slivers are important tectonic elements of orogenic belts worldwide. In this study we used high-resolution topography, geodetic imaging, seismic, and geologic data to advance understanding of how these features evolved during accretion of the Yakutat Terrane to North America. Because glaciers extend over much of the orogen, the topography and dynamics of the glaciers were analyzed to infer the location and nature of faults and shear zones that lie buried beneath the ice. The Fairweather transform fault system terminates by obliqueextensional splay faulting within a structural syntaxis, where thrust faulting and contractional strain drive rapid tectonic uplift and rock exhumation beneath the upper Seward Glacier. West of the syntaxis, oblique plate convergence created a dextral shear zone beneath the Bagley Ice Valley that may have been reactivated by reverse faulting when the subduction megathrust stepped eastward during the last 5-6 Ma. The Bagley fault zone dips steeply through the upper plate to intersect the subduction megathrust at depth, forming a fault-bounded crustal sliver capable of partitioning oblique convergence into strike-slip and thrust motion. Since ca. 20 Ma the Bagley fault accommodated more than 50 km of dextral shearing and several kilometers of reverse motion along its southern fl ank during terrane accretion. The fault is considered capable of generating earthquakes because it is suitably oriented for reactivation in the contemporary stress fi eld, links to faults that

show abstract

Seismic velocity structure and anisotropy of the Alaska subduction zone based on surface wave tomography

Wang

Tape

2014

JGR Solid Earth

View full text Add to dashboard Cite

Southcentral Alaska is a complex tectonic region that transitions from subduction of Pacific crust to flat slab subduction—and collision—of overthickened Yakutat crust. Because much of the Yakutat crust has been subducted, seismic imaging is needed in order to understand the crustal and upper mantle structural framework for this active tectonic setting. Here we use teleseismic Rayleigh waves to image large‐scale variations in shear wave structure. Our imaging technique employs a two‐plane wave representation with finite frequency sensitivity kernels. Our 3‐D isotropic model reveals several features: the subducting Pacific/Yakutat slab, slow wave speeds characterizing the onshore Yakutat collision zone, slow wave speeds of the Wrangell subduction zone, and a deep tomographic contrast at the eastern edge of the Pacific/Yakutat slab. We produce anisotropic phase velocity maps that exhibit variations in the fast direction of azimuthal anisotropy. These maps show the dominance of the Yakutat slab on the observed pattern of anisotropy. West of the Yakutat slab the fast directions are approximately aligned with the plate convergence direction. In the region of the Yakutat slab the pattern is more complicated. Along the margins of the slab the fast directions are roughly parallel to the margins. We identify notable differences and similarities with published SKS splitting measurements. Integrative modeling using 3‐D anisotropy models and different seismic measurements will be needed in order to establish a detailed 3‐D anisotropic velocity model for Alaska. This study provides a large‐scale starting point for such an effort.

show abstract

Untitled

Cited by 25 publications

References 21 publications

Introduction: Neogene tectonics and climate-tectonic interactions in the southern Alaskan orogen themed issue

Introduction: Neogene tectonics and climate-tectonic interactions in the southern Alaskan orogen themed issue

Untitled

Seismic velocity structure and anisotropy of the Alaska subduction zone based on surface wave tomography

Contact Info

Product

Resources

About