Aftershock Sequence of the Mw 7.9 Denali Fault, Alaska, Earthquake of 3 November 2002 from Regional Seismic Network Data

Ratchkovski, Natalia A.; Hansen, R. A.; Stachnik, J. C.; Cox, T.; Fox, O.; Rao, Lubei; Clark, Edward P.; Lafevers, M.; Estes, S.; MacCormack, J. B.; Williams, T.

doi:10.1785/gssrl.74.6.743

Cited by 38 publications

(18 citation statements)

References 24 publications

(13 reference statements)

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“…This region has previously been suggested as a region of low moment release by Eberhart‐Phillips et al [2003], Ozacar and Beck [2004], and Oglesby et al [2004]. The lack of aftershocks in the region led Ratchkovski et al [2003] to suggest that this is a creeping section of the fault. Geodetic data from the Black Rapids Glacier region (44–54 km east of the epicenter) suggest ∼4 m of slip in the region and our preferred coseismic slip model shows 2–4 m of slip from about 30 to 60 km east of the epicenter, smoothly varying along strike and with depth.…”

Section: Discussionmentioning

confidence: 76%

“…Aftershocks occurring within an hour of the earthquake indicate that the earthquake ruptured about 30 km of the Denali Fault toward the west from the epicenter. Relocated aftershocks show that the majority of the aftershocks occurred between 3 and 12 km depth, forming a vertical plane beneath the surface trace [ Ratchkovski et al , 2003]. …”

Section: Coseismic Deformation Of the Nenana Mountain Earthquakementioning

confidence: 99%

“…The upper plane, from 0 to 2 km depth, intersects the surface roughly at the observed surface rupture with a dip of 19° to match estimates from geological field measurements [ Crone et al , 2004]. From 2 to 8.6 km depth we use a plane with a dip of 48° to match the first motion focal mechanism from the local network [ Ratchkovski et al , 2003]. The lower plane intersects with the Denali Fault at its base.…”

Section: Inversion On 3‐d Fault Model In Elastic Half‐spacementioning

confidence: 99%

“…Prior to the 2002 earthquake sequence, the level of recorded seismicity along the Denali Fault was very low. The seismic behavior of the Denali Fault seems to be characterized by infrequent large earthquakes with quiet periods in between [ Ratchkovski et al , 2003]. In 1912 an M 7.2 earthquake occurred in the region (between −144.5 and −149.5°E) and possibly ruptured the Denali Fault [ Doser , 2004].…”

Section: Introductionmentioning

confidence: 99%

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Coseismic deformation of the 2002 Denali Fault earthquake: Insights from GPS measurements

et al. 2006

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[1] We estimate coseismic displacements from the 2002 M w 7.9 Denali Fault earthquake at 232 GPS sites in Alaska and Canada. Displacements along a N-S profile crossing the fault indicate right-lateral slip on a near-vertical fault with a significant component of vertical motion, north-side up. We invert both GPS displacements and geologic surface offsets for slip on a three-dimensional (3-D) fault model in an elastic half-space. We restrict the motion to right-lateral slip and north-side-up dip slip. Allowing for oblique slip along the Denali and Totschunda faults improves the model fit to the GPS data by about 30%. We see mostly right-lateral strike-slip motion on the Denali and Totschunda faults, but in a few areas we see a significant component of dip slip. The slip model shows increasing slip from west to east along the Denali Fault, with four localized higherslip patches, three near the Trans-Alaska pipeline crossing and a large slip patch corresponding to a M w 7.5 subevent about 40 km west of the Denali-Totschunda junction. Slip of 1-3 m was estimated along the Totschunda Fault with the majority of slip being at shallower than 9 km depth. We have limited resolution on the Susitna Glacier Fault, but the estimated slip along the fault is consistent with a M w 7.2 thrust subevent. Total estimated moment in the Denali Fault earthquake is equivalent to M w 7.89. The estimated slip distribution along the surface is in very good agreement with geological surface offsets, but we find that surface offsets measured on glaciers are biased toward lower values.

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Section: Discussionmentioning

confidence: 76%

Section: Coseismic Deformation Of the Nenana Mountain Earthquakementioning

confidence: 99%

Section: Inversion On 3‐d Fault Model In Elastic Half‐spacementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Coseismic deformation of the 2002 Denali Fault earthquake: Insights from GPS measurements

et al. 2006

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“…The entire Denali fault is low in seismic activity prior to the mainshock, and even after the event, deep microseismicity is absent for nearly all segments over depths greater than ~8 km (Fig. S6, panel A, B; 25,52).…”

Section: Microseismicity Vs the Depth Extent Of Earthquakes From Slimentioning

confidence: 99%

Deeper penetration of large earthquakes on seismically quiescent faults

Jiang

Lapusta

2016

Science

119

110

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A microseismic turn off Certain strike-slip faults do not have the expected number of microearthquakes between larger earthquakes. Jiang and Lapusta suggest that this behavior is down to what the last big earthquake looked like. They found that microseismicity turns off if an earthquake's rupture runs deeper than the fault's locking depth. This appears to be the case along the famous San Andreas Fault and also along other strike-slip faults around the world. The discovery may allow for better estimates of historic earthquake magnitudes and improve hazard assessments. Science , this issue p. 1293

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Aftershocks of the 2010 M_w 7.2 El Mayor‐Cucapah earthquake reveal complex faulting in the Yuha Desert, California

et al. 2013

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[1] We detect and precisely locate over 9500 aftershocks that occurred in the Yuha Desert region during a 2 month period following the 4 April 2010 M w 7.2 El Mayor-Cucapah (EMC) earthquake. Events are relocated using a series of absolute and relative relocation procedures that include Hypoinverse, Velest, and hypoDD. Location errors are reduced to 40 m horizontally and 120 m vertically. Aftershock locations reveal a complex pattern of faulting with en echelon fault segments trending toward the northwest, approximately parallel to the North American-Pacific plate boundary and en echelon, conjugate features trending to the northeast. The relocated seismicity is highly correlated with published surface mapping of faults that experienced triggered surface slip in response to the EMC main shock. Aftershocks occurred between 2 km and 11 km depths, consistent with previous studies of seismogenic thickness in the region. Three-dimensional analysis reveals individual and intersecting fault planes that are limited in their along-strike length. These fault planes remain distinct structures at depth, indicative of conjugate faulting, and do not appear to coalesce onto a throughgoing fault segment. We observe a complex spatiotemporal migration of aftershocks, with seismicity that jumps between individual fault segments that are active for only a few days to weeks. Aftershock rates are roughly consistent with the expected earthquake production rates of Dieterich (1994). The conjugate pattern of faulting and nonuniform aftershock migration patterns suggest that strain in the Yuha Desert is being accommodated in a complex manner.

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Aftershock Sequence of the Mw 7.9 Denali Fault, Alaska, Earthquake of 3 November 2002 from Regional Seismic Network Data

Cited by 38 publications

References 24 publications

Coseismic deformation of the 2002 Denali Fault earthquake: Insights from GPS measurements

Coseismic deformation of the 2002 Denali Fault earthquake: Insights from GPS measurements

Deeper penetration of large earthquakes on seismically quiescent faults

Aftershocks of the 2010 M_w 7.2 El Mayor‐Cucapah earthquake reveal complex faulting in the Yuha Desert, California

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Aftershock Sequence of the Mw 7.9 Denali Fault, Alaska, Earthquake of 3 November 2002 from Regional Seismic Network Data

Cited by 38 publications

References 24 publications

Coseismic deformation of the 2002 Denali Fault earthquake: Insights from GPS measurements

Coseismic deformation of the 2002 Denali Fault earthquake: Insights from GPS measurements

Deeper penetration of large earthquakes on seismically quiescent faults

Aftershocks of the 2010 Mw 7.2 El Mayor‐Cucapah earthquake reveal complex faulting in the Yuha Desert, California

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Aftershocks of the 2010 M_w 7.2 El Mayor‐Cucapah earthquake reveal complex faulting in the Yuha Desert, California