The 1904<i>M</i><sub>s</sub> 7.3 Earthquake in Central Alaska

Tape, Carl; Lomax, Anthony; Silwal, Vipul; Agnew, James D.; Brettschneider, Brian

doi:10.1785/0120160178

Cited by 4 publications

(4 citation statements)

References 57 publications

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“…The events with the largest discrepancies are labeled; these events tend to also have the highest uncertainty estimates. The general epicenter differences of 10–30 km agree with estimates of absolute teleseismic location errors (Wyss et al., 2011), and some bias in epicenter is to be expected due to differences in station corrections, location algorithm, and effective weighing of heterogeneously distributed stations (e.g., generally higher density of stations to the north in Europe for earlier events (Tape et al., 2017), and of nearby stations to the northeast in Alaska for later events).…”

Section: Relocation Of 553 Earthquakes Using Nonlinlocsupporting

confidence: 69%

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Aftershock Regions of Aleutian‐Alaska Megathrust Earthquakes, 1938–2021

Tape

Lomax²

2022

JGR Solid Earth

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With five earthquakes (1938, 1946, 1957, 1964, and 1965), the Aleutian‐Alaska subduction plate boundary ruptured a length of 3,548 km. We revisit these five earthquakes—first studied in detail by Sykes (1971, https://doi.org/10.1029/JB076i032p08021)—through probabilistic relocation of carefully selected mainshocks and aftershocks. Our final catalog of 324 events is established from a set of 12 mainshocks that includes all Mw ≥ 7.7 megathrust earthquakes. Using the relocated catalog, we create revised aftershock regions delimited both parallel and normal to the trench. These aftershock regions exhibit significant differences from previous studies, with the following basic findings: the 10 November 1938 Mw 8.3 earthquake extended further west, to the Shumagin Islands, and further east, into the Kodiak region, relative to the prevailing aftershock region established by McCann et al. (1979, https://doi.org/10.1007/978-3-0348-6430-5_2). The 01 April 1946 Mw 8.6 sequence was anomalously concentrated near the trench, which implies near‐trench coseismic slip that contributed to the exceptionally large tsunami. The 09 March 1957 Mw 8.6 aftershocks spanned a 1,230 km length with numerous aftershocks within the outer‐rise region of the incoming Pacific plate. The 28 March 1964 Mw 9.2 aftershocks extended east into the Pamplona thrust system (south of Icy Bay, Alaska), suggesting coseismic rupture into this region; this is consistent with coseismic static displacements, as well as current estimates of interseismic locking. The post‐1965 events we examine are all smaller than the earlier events, but since they occurred in an era of improved data collection (seismic, geodetic, and tsunami), they provide a better opportunity for assessing the link between the distribution of aftershocks and the occurrence of coseismic, postseismic, and interseismic slip.

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Section: Relocation Of 553 Earthquakes Using Nonlinlocsupporting

confidence: 69%

“…A second pass of relocations using these static corrections form the final relocated catalog presented and discussed in this study. For more details see application of NLL using historical data (Lomax, 2005(Lomax, , 2008Silwal et al, 2018;Tape et al, 2017Tape et al, , 2021.…”

Section: Relocation Of 553 Earthquakes Using Nonlinlocmentioning

confidence: 99%

Aftershock Regions of Aleutian‐Alaska Megathrust Earthquakes, 1938–2021

Tape

Lomax²

2022

JGR Solid Earth

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“…Apart from an abundance of seismicity [ Moschetti et al , ; Mueller et al , ; Tape et al , ], earthquake focal mechanism across Alaska [ Ruppert , ] show a variety of faulting regimes, with strike‐slip and reverse faulting contributing the most to the maximum horizontal stress field in south central Alaska [ Ruppert , ; Ghosh and Holt , ]. A regional stress map [ Ruppert , ] shows maximum horizontal stress in a strike‐slip, or fault‐parallel, motion along the eastern Denali fault and more reverse faulting, or compression/convergence, along the central Denali fault, which is similar to the findings in this study.…”

Section: Discussionmentioning

confidence: 99%

Tectonic drivers of the Wrangell block: Insights on fore‐arc sliver processes from 3‐D geodynamic models of Alaska

Haynie

Jadamec

2017

Tectonics

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Intracontinental shear zones can play a key role in understanding how plate convergence is manifested in the upper plate in regions of oblique subduction. However, the relative role of the driving forces from the subducting plate and the resisting force from within intracontinental shear zones is not well understood. Results from high‐resolution, geographically referenced, instantaneous 3‐D geodynamic models of flat slab subduction at the oblique convergent margin of Alaska are presented. These models investigate how viscosity and length of the Denali fault intracontinental shear zone as well as coupling along the plate boundary interface modulate motion of the Wrangell block fore‐arc sliver and slip across the Denali fault. Models with a weak Denali fault (1017 Pa s) and strong plate coupling (1021 Pa s) were found to produce the fastest motions of the Wrangell block (∼10 mm/yr). The 3‐D models predict along‐strike variation in motion along the Denali fault, changing from dextral strike‐slip motion in the eastern segment to oblique convergence toward the fault apex. Models further show that the flat slab drives oblique motion of the Wrangell block and contributes to 20% (models with a short fault) and 28% (models with a long fault) of the observed Quaternary slip rates along the Denali fault. The 3‐D models provide insight into the general processes of fore‐arc sliver mechanics and also offer a 3‐D framework for interpreting hazards in regions of flat slab subduction.

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“…Murphy, 2019). Tape et al (2017) argue a 1904 Ms7.3 earthquake occurred along this fault zone. The fault is shown to be about 355-km long in our model, but only a 113-km-long stretch of the Iditarod-Nixon Fork Fault system has a clear scarp on the ArcticDEM that cuts Quaternary sediments .…”

Section: Fairbanks and North Central Interior Alaskamentioning

confidence: 93%

Updating the Crustal Fault Model for the 2023 National Seismic Hazard Model for Alaska

Haeussler,

Bender,

Powers

et al. 2023

Preprint

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We present the crustal fault model for Alaska, based on geologic observations, as a primary input for the 2023 revision of the U.S. Geological Survey National Seismic Hazard Model (NSHM). We update the 2013 Alaska Quaternary fault and fold database (Koehler, 2013) with subsequent findings to produce a simplified model of 105 fault sections and four fault zone polygons with basic geologic parameters including slip sense and rate. Significant updates from prior maps include: 1) A slip rate of ~53 mm/yr on the Queen Charlotte Fault system indicating it accommodates all of the plate boundary motion. 2) Quantified long-term slip rates on megathrust splay faults in the southern Prince William Sound region and near Kodiak Island. 3) Improved details of structures in the Chugach-St. Elias orogen. 4) Revised characterization of Castle Mountain Fault from right-lateral slip to a predominantly reverse fault. 5) Improved Interior Alaska tectonic models that clarify relationships between the Denali Fault, Totschunda Fault, and thrust faults on both sides of the Alaska Range. 6) Identified large earthquake sources in the eastern Brooks Range. 7) Omission of the Chatham Strait section of the Denali Fault. We also describe the growing body of Alaskan lacustrine paleoseismic records of strong shaking, which may offer a test of ground motion recurrence predicted by the 2023 NSHM for crustal, megathrust, and intraslab events. The fault model underscores that the collision of the Yakutat microplate is the dominant driver of active crustal faulting in most of Alaska.

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The 1904M_s 7.3 Earthquake in Central Alaska

Cited by 4 publications

References 57 publications

Aftershock Regions of Aleutian‐Alaska Megathrust Earthquakes, 1938–2021

Aftershock Regions of Aleutian‐Alaska Megathrust Earthquakes, 1938–2021

Tectonic drivers of the Wrangell block: Insights on fore‐arc sliver processes from 3‐D geodynamic models of Alaska

Updating the Crustal Fault Model for the 2023 National Seismic Hazard Model for Alaska

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The 1904Ms 7.3 Earthquake in Central Alaska

Cited by 4 publications

References 57 publications

Aftershock Regions of Aleutian‐Alaska Megathrust Earthquakes, 1938–2021

Aftershock Regions of Aleutian‐Alaska Megathrust Earthquakes, 1938–2021

Tectonic drivers of the Wrangell block: Insights on fore‐arc sliver processes from 3‐D geodynamic models of Alaska

Updating the Crustal Fault Model for the 2023 National Seismic Hazard Model for Alaska

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The 1904M_s 7.3 Earthquake in Central Alaska