Seismicity of the Kodiak Island Region (1964-2001) and Its Relation to the 1964 Great Alaska Earthquake

Doser, Diane I.; Brown, Wesley A.; Velasquez, Monique

doi:10.1785/0120010280

Cited by 15 publications

(16 citation statements)

References 30 publications

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“…Similar literature exists for the Semidi segment that spans the region to the southwest of the Kodiak Islands (Johnson and Satake, 1994;Fournier and Freymueller, 2007;Shillington et al, 2015). However, segment boundaries for the Kodiak region have been largely defined by island-based paleoseismic studies and the inferred behavior of subducted lower plate topography from seismicity Doser et al, 2002;von Huene et al, 2012;Briggs et al, 2014;Shennan et al, 2014). Table 1 In this thesis, I explore the geophysical expression of the presumed Kodiak segment boundaries by analyzing several geophysical datasets (potential fields, seismic reflection, and seismicity data) in the context of lower and upper plate structure.…”

mentioning

confidence: 84%

“…The Kodiak segment has experienced larger and more frequent interseismic events relative to the PWS and Kenai segments both before and after the 1964 event (Doser et al, 2002;Doser, 2005;Doser, 2006). Large modern earthquakes have mostly occurred in the southwest Kodiak region, with a majority of these events presumably nucleating within the subducting Pacific slab (Ratchkovski and Hansen, 2001;Doser et al, 2002).…”

Section: Kodiak Segment Seismicitymentioning

confidence: 99%

“…Large modern earthquakes have mostly occurred in the southwest Kodiak region, with a majority of these events presumably nucleating within the subducting Pacific slab (Ratchkovski and Hansen, 2001;Doser et al, 2002). In contrast, there has been a paucity of pre and post-1964 large earthquakes associated with the eastern and central portions of the Kodiak segment (Doser et al, 2002). These observations suggest that consistent seismotectonic controls have persisted along the Kodiak segment for multiple megathrust earthquake cycles, and a kinematic, structural model for these observations has yet to be invoked.…”

Section: Kodiak Segment Seismicitymentioning

confidence: 99%

“…Historic seismicity patterns show that the seaward portion of the southwest Kodiak Islands region has repeatedly had more earthquakes relative to the rest of the segment, which suggests a persistent stress-field across the earthquake cycle in this region (Doser et al, 2002;Doser, 2005;Sauber et al, 2006). Scholz and Campos (2012) showed that megathrust coupling patterns observed during the interseismic period are dependent on the phase of the megathrust earthquake cycle and only in general may asperity and strain accumulation match one another from one earthquake cycle to another.…”

Section: Tsunamigenic Fault Hazards For the Kodiak Segmentmentioning

confidence: 99%

“…The southwest portion of the Kodiak segment experiences greater interseismic moment-release relative to the rest of the Kodiak segment (Doser et al, 2002). In particular, focal mechanisms indicative of low-angle, lower crustal thrusting dominate the interseismic character of intermediate (5 < Mw < 7) magnitude events in this region (Figure 26).…”

Section: Interseismic Observationsmentioning

confidence: 99%

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Earthquake Segment Boundaries and Tsunamigenic Faults of the Kodiak Segment, Alaska-Aleutian Subduction Zone

Ramos¹

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The final reading approval of the thesis was granted by Lee M. Liberty, M.S. Chair of the Supervisory Committee. The thesis was approved by the Graduate College. The northeast Kodiak segment boundary is defined by the subducting 58° fracture zone, which can be traced below the forearc using magnetic and gravitational fields.Subduction of this feature is expressed on post-1964 seismicity, is consistent with oblique shortening, and manifests itself within the upper plate as the Portlock Anticline.The southwest segment boundary marks the transition between the Kodiak and Semidi segments. It is shown to be a region that shifts from significant margin erosion to a region of imbricate thrusting and margin growth. These two zones are bound by fracture zone subduction. I furthermore independently constrain and compliment vii paleoseismological models of joint Kodiak and Semidi segment rupture by identifying and characterizing a through-going marine fault zone across this segment boundary.Finally, I revisit the source mechanisms for the local tsunami that inundated the Kodiak Islands as a result of the 1964 earthquake. I provide a new tsunamigenic source model that suggests discrete uplift of the Kodiak Islands shelf fault system and illuminate its along-strike rupture variability throughout the Holoecene epoch.My findings suggest segment boundaries across Kodiak have a clear geophysical expression and a multi-dataset approach is necessary to decipher tectonic controls on megathrust segmentation.

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confidence: 84%

Section: Kodiak Segment Seismicitymentioning

confidence: 99%

Section: Kodiak Segment Seismicitymentioning

confidence: 99%

Section: Tsunamigenic Fault Hazards For the Kodiak Segmentmentioning

confidence: 99%

Section: Interseismic Observationsmentioning

confidence: 99%

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Earthquake Segment Boundaries and Tsunamigenic Faults of the Kodiak Segment, Alaska-Aleutian Subduction Zone

Ramos¹

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Crustal earthquake triggering by modern great earthquakes on subduction zone thrusts

Gomberg

Sherrod

2014

J. Geophys. Res. Solid Earth

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Among the many questions raised by the recent abundance of great (M > 8.0) subduction thrust earthquakes is their potential to trigger damaging earthquakes on crustal faults within the overriding plate and beneath many of the world's densely populated urban centers. We take advantage of the coincident abundance of great earthquakes globally and instrumental observations since 1960 to assess this triggering potential by analyzing centroids and focal mechanisms from the centroid moment tensor catalog for events starting in 1976 and published reports about the M9.5 1960 Chile and M9.2 1964 Alaska earthquake sequences. We find clear increases in the rates of crustal earthquakes in the overriding plate within days following all subduction thrust earthquakes of M > 8.6, within about ±10°of the triggering event centroid latitude and longitude. This result is consistent with dynamic triggering of more distant increases of shallow seismicity rates at distances beyond ±10°, suggesting that dynamic triggering may be important within the near field too. Crustal earthquake rate increases may also follow smaller M > 7.5 subduction thrust events, but because activity typically occurs offshore in the immediately vicinity of the triggering rupture plane, it cannot be unambiguously attributed to sources within the overriding plate. These observations are easily explained in the context of existing earthquake scaling laws.

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Subduction Zone Interface Structure within the Southern MW9.2 1964 Great Alaska Earthquake Asperity: Constraints from Receiver Functions Across a Spatially Dense Node Array

Onyango¹,

Worthington²,

Schmandt³

et al. 2022

Preprint

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Seismicity of the Kodiak Island Region (1964-2001) and Its Relation to the 1964 Great Alaska Earthquake

Cited by 15 publications

References 30 publications

Earthquake Segment Boundaries and Tsunamigenic Faults of the Kodiak Segment, Alaska-Aleutian Subduction Zone

Earthquake Segment Boundaries and Tsunamigenic Faults of the Kodiak Segment, Alaska-Aleutian Subduction Zone

Crustal earthquake triggering by modern great earthquakes on subduction zone thrusts

Subduction Zone Interface Structure within the Southern MW9.2 1964 Great Alaska Earthquake Asperity: Constraints from Receiver Functions Across a Spatially Dense Node Array

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