Landslides Triggered by the 2002 Denali Fault, Alaska, Earthquake and the Inferred Nature of the Strong Shaking

2004 ◽  
Vol 20 (3) ◽  
pp. 669-691 ◽  
Author(s):  
Randall W. Jibson ◽  
Edwin L. Harp ◽  
William Schulz ◽  
David K. Keefer

The 2002 M7.9 Denali fault, Alaska, earthquake triggered thousands of landslides, primarily rock falls and rock slides, that ranged in volume from rock falls of a few cubic meters to rock avalanches having volumes as great as 15×106m3. The pattern of landsliding was unusual; the number of slides was less than expected for an earthquake of this magnitude, and the landslides were concentrated in a narrow zone 30-km wide that straddled the fault rupture over its entire 300-km length. The large rock avalanches all clustered along the western third of the rupture zone where acceleration levels and ground-shaking frequencies are thought to have been the highest. Inferences about near-field strong shaking characteristics drawn from the interpretation of the landslide distribution are consistent with results of recent inversion modeling that indicate high-frequency energy generation was greatest in the western part of the fault rupture zone and decreased markedly to the east.

2006 ◽  
Vol 83 (1-3) ◽  
pp. 144-160 ◽  
Author(s):  
Randall W. Jibson ◽  
Edwin L. Harp ◽  
William Schulz ◽  
David K. Keefer

Author(s):  
Gabriele Chiaro ◽  
Gavin Alexander ◽  
Pathmanathan Brabhaharan ◽  
Christopher Massey ◽  
Junichi Koseki ◽  
...  

On 16 April 2016, a moment magnitude (Mw) 7.0 earthquake struck the Island of Kyushu, Japan. Two major foreshocks (Mw 6.2 and Mw 6.0) contributed to devastation in Kumamoto City, Mashiki Town and in the mountainous areas of the Mount Aso volcanic caldera. This report summarises geotechnical and geological aspects of the earthquakes that were observed during a field investigation conducted by the NZSEE Team in collaboration with Japanese engineers and researchers. Many houses and other buildings, roads, riverbanks, and an earth dam, either on or adjacent to the surface fault rupture or projected fault trace, were severely damaged as a result of both the strong ground shaking and permanent ground displacement. In the Mount Aso volcanic caldera, traces of medium to large scale landslides and rock falls were frequently observed. A number of landslides impacted homes and infrastructure, and were reported to have killed at least 10 people out of the 69 confirmed deaths associated with the earthquake. In a few suburbs of Kumamoto City and in Mashiki Town, localised liquefaction took place, causing lateral spreading, differential settlements of the ground and riverbanks, sinking and tilting of buildings, foundation failures, cracks on roads, and disruption of water and sewage pipe networks. The overall effects from liquefaction related hazards appeared relatively minor compared to the damage caused by shaking, landslides and surface fault rupture. Based on the field survey, key findings are highlighted and recommendations to NZ engineering practice are made in the report.


2019 ◽  
Vol 91 (1) ◽  
pp. 19-32 ◽  
Author(s):  
Randall W. Jibson ◽  
Alex R. R. Grant ◽  
Robert C. Witter ◽  
Kate E. Allstadt ◽  
Eric M. Thompson ◽  
...  

Abstract Investigation of ground failure triggered by the 2018 Mw 7.1 Anchorage earthquake showed that landslides, liquefaction, and ground cracking all occurred and caused significant damage. Shallow rock falls and rock slides were the most abundant types of landslides, but they occurred in smaller numbers than global models that are based on earthquake magnitude predict; this might result from the 2018 earthquake being an intraslab event. Liquefaction was common in alluvial and intertidal areas; ground deformation probably related to liquefaction damaged numerous houses and port facilities in Anchorage. Ground cracking was pervasive near the edges of slopes in hilly areas and caused perhaps the most significant property damage of all types of ground failure. A complex of slump–earth flows was triggered along coastal bluffs in southern Anchorage where slides also occurred in 1964; the 2018 slides involved both mobilization of new landside material and reactivation of parts of the 1964 landslide deposits. Large translational slides that formed during the 1964 Alaska earthquake showed evidence of deformation along pre‐existing failure surfaces but did not reactivate with new net downslope displacement. Modeling suggests that ground motion in 2018 was of insufficient duration and too high frequency to trigger reactivation of the deep landslides.


2004 ◽  
Vol 20 (3) ◽  
pp. 579-596 ◽  
Author(s):  
Artak Martirosyan ◽  
Roger Hansen ◽  
Natalia Ratchkovski

The MW 7.9 Denali Fault earthquake on 3 November 2002 ruptured a 340-km section along the Susitna Glacier, Denali, and Totschunda faults in central Alaska. The earthquake was digitally recorded at more than 55 strong-motion sites throughout the state at distances up to 280 km from the fault rupture. The site closest to the fault, Trans-Alaska Pipeline Pump Station 10, is located about 3 km north of the surface rupture, where the observed maximum horizontal peak ground acceleration was about 0.35 g. The peak horizontal accelerations observed at the sites closest to the fault rupture were considerably smaller than those yielded by the ground-motion prediction equations. Although the earthquake provided a valuable set of strong-motion data, an important opportunity was missed to capture near-field recordings from such a major strike-slip event. A concerted national effort is needed to prioritize the instrumentation of faults that are likely locations of future great earthquakes.


Atmosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 83
Author(s):  
Yongming Zhang ◽  
Xin Liu ◽  
Jinyun Guo ◽  
Kunpeng Shi ◽  
Maosheng Zhou ◽  
...  

The Mw7.9 Alaska earthquake at 09:31:40 UTC on 23 January 2018 occurred as the result of strike slip faulting within the shallow lithosphere of the Pacific plate. Global positioning system (GPS) data were used to calculate the slant total electron contents above the epicenter. The singular spectrum analysis (SSA) method was used to extract detailed ionospheric disturbance information, and to monitor the co-seismic ionospheric disturbances (CIDs) of the Alaska earthquake. The results show that the near-field CIDs were detected 8–12 min after the main shock, and the typical compression-rarefaction wave (N-shaped wave) appeared. The ionospheric disturbances propagate to the southwest at a horizontal velocity of 2.61 km/s within 500 km from the epicenter. The maximum amplitude of CIDs appears about 0.16 TECU (1TECU = 1016 el m−2) near the epicenter, and gradually decreases with the location of sub-ionospheric points (SIPs) far away from the epicenter. The attenuation rate of amplitude slows down as the distance between the SIPs and the epicenter increases. The direction of the CIDs caused by strike-slip faults may be affected by the horizontal direction of fault slip. The propagation characteristics of the ionospheric disturbance in the Alaska earthquake may be related to the complex conditions of focal mechanisms and fault location.


2007 ◽  
Vol 20 (6) ◽  
pp. 597-604
Author(s):  
Xue-feng Shang ◽  
Qi-ming Liu ◽  
Hai-ming Zhang ◽  
Xiao-fei Chen

AIP Advances ◽  
2014 ◽  
Vol 4 (4) ◽  
pp. 047114 ◽  
Author(s):  
Z. Wu ◽  
A. D. Souza ◽  
B. Peng ◽  
W. Q. Sun ◽  
S. Y. Xu ◽  
...  

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