Plate kinematics of the Denali fault system

1980 ◽  
Vol 17 (11) ◽  
pp. 1527-1537 ◽  
Author(s):  
James H. Stout ◽  
Clement G. Chase
Keyword(s):  
Plate Tectonics ◽  
Plate Boundary ◽  
Gulf Of Alaska ◽  
Fault System ◽  
Time Interval ◽  
Intrinsic Properties ◽  
Denali Fault ◽  
Tectonic Transport ◽  
The Right ◽  
Plate Kinematics

Two segments of the Denali fault system, the McKinley strand west of the Delta River and the Dalton–Shakwak fault east of the Delta River, have nearly perfect small circle geometries. This geometry permits interpretation of the right-lateral slip along these faults in terms of rigid plate tectonics. Their poles of rotation are in the Gulf of Alaska at 59.63°N, 147.38°W and 50.38°N, 154.02°W respectively. A model in which there has been simultaneous motion on both faults since 38 Ma ago predicts a third fault at their juncture which must act as a plate boundary with northwesterly thrust motion in this time interval. The Broxson Gulch thrust, which extends from near the Susitna River to its termination at the Delta River, meets these requirements. Paleozoic and Mesozoic volcanics, as well as Oligocene or younger strata, are thrust beneath sillimanite schists along this fault, and major pre-Tertiary fold structures are truncated by it. Given the direction of tectonic transport on all three faults and a displacement of 38 km on the McKinley strand, the minimum displacements on the Broxson Gulch and the Denali (Dalton–Shakwak) faults in the last 38 Ma are approximately 54 and 90 km respectively. The previously correlated Maclaren and Ruby Range metamorphic belts, however, indicate 300–400 km offset since about 55 Ma ago. Our results require that about 300 km of this be taken up west of the Maclaren belt, either on the McKinley strand or on thrust segments similar to the Broxson Gulch, or both. Our results further indicate that the arcuate shape of these segments of the Denali fault system are intrinsic properties of the faults themselves and that oroclinal bending need not be invoked to explain them.

scholarly journals The Ulakhan fault surface rupture and the seismicity of the Okhotsk–North America plate boundary

Solid Earth ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 561-580 ◽  
Author(s):  
David Hindle ◽  
Boris Sedov ◽  
Susanne Lindauer ◽  
Kevin Mackey
Keyword(s):  
North America ◽  
Plate Tectonics ◽  
Plate Boundary ◽  
Slip Rate ◽  
Field Work ◽  
Alluvial Fan ◽  
Age Dating ◽  
Aerial Photographs ◽  
Fault System ◽  
Fault Surface

Abstract. New field work, combined with analysis of high-resolution aerial photographs, digital elevation models, and satellite imagery, has identified an active fault that is traceable for ∼90 km across the Seymchan Basin and is part of the Ulakhan fault system, which is believed to form the Okhotsk–North America plate boundary. Age dating of alluvial fan sediments in a channel system that is disturbed by fault activity suggests the current scarp is a result of a series of large earthquakes (≥Mw 7.5) that have occurred since 11.6±2.7 ka. A possible channel feature offset by 62±4 m associated with these sediments yields a slip rate of 5.3±1.3 mm yr−1, in broad agreement with rates suggested from global plate tectonics. Our results clearly identify the Ulakhan fault as the Okhotsk–North America plate boundary and show that tectonic strain release is strongly concentrated on the boundaries of Okhotsk. In light of our results, the likelihood of recurrence of Mw 7.5 earthquakes is high, suggesting a previously underestimated seismic hazard across the region.

scholarly journals The Ulakhan fault surface rupture and the seismicity of the Okhotsk-North America plate boundary

2018 ◽  
Author(s):  
David Hindle ◽  
Boris Sedov ◽  
Susanne Lindauer ◽  
Kevin Mackey
Keyword(s):  
North America ◽  
Plate Tectonics ◽  
Plate Boundary ◽  
Slip Rate ◽  
Field Work ◽  
Alluvial Fan ◽  
Age Dating ◽  
Aerial Photographs ◽  
Fault System ◽  
Fault Surface

Abstract. New field work, combined with analysis of aerial photographs, high resolution, digital elevation models, and satellite imagery has identified an active fault that is traceable for ∼ 90 km across the Seymchan Basin, and is part of the Ulakhan fault system, which is believed to form the Okhtotsk-North America plate boundary. Age dating of alluvial fan sediments in a channel system that is disturbed by and abandoned due to fault activity, suggest the current scarp is a result of a series of large earthquakes (≥ Mw 7.5) that have occurred since ∼11.5 ka. A possible offset channel edge associated with these sediments yields a slip rate of ∼ 5–6 mm yr−1, in broad agreement with rates suggested from global plate tectonics and other theoretical studies. Our results clearly identify the Ulakhan fault as the Okhotsk-North America plate boundary, and show that tectonic strain release is strongly concentrated on the boundaries of Okhotsk. In the light of our results, the likelihood of recurrence of Mw 7.5 earthquakes is high, raising serious questions of seismic hazard across the region.

scholarly journals Latest Quaternary Active Faulting and Paleoearthquakes on the Southern Segment of the Xiaojiang Fault Zone, SE Tibetan Plateau

Lithosphere ◽  
2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Peng Guo ◽  
Zhujun Han ◽  
Shaopeng Dong ◽  
Zebin Mao ◽  
Nan Hu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Fault Zone ◽  
Dominant Role ◽  
Fault System ◽  
Tectonic Deformation ◽  
Time Interval ◽  
The Tibetan Plateau ◽  
Lateral Extrusion ◽  
The Right ◽  
Xiaojiang Fault

Abstract The Xiaojiang fault zone (XJFZ) is an important part of the Xianshuihe-Xiaojiang fault system, acting as the eastern boundary of the Chuan-Dian block on the southeastern margin of the Tibetan Plateau and accommodating the lateral extrusion of the block. The faulting activity and paleoseismic history on the southern segment of the XJFZ remain poorly understood. Here, trench excavations and radiocarbon dating revealed that four recent surface-rupturing paleoearthquakes have occurred on the Jianshui fault (JSF) in the southern segment of the XJFZ since ~15370 yr BP. The ages of these events, labeled E4-E1 from oldest to youngest, are limited to the following time ranges: 15360-12755, 10845-6900, 1455-670, and 635-145 yr BP, respectively. The most recent event E1 was most likely the 1606 Jianshui earthquake. These events appear to occur unregularly in time. The time interval between the last two events is 726±235 yr, and the average recurrence interval for all four events is 4589±3132 yr. The deformed strata show that the JSF is characterized kinematically by transtension, which likely respond to the apparent change in the direction of clockwise rotation of the Chuan-Dian block around the eastern Himalayan syntaxis. Combined with the analysis of the neighboring NW-striking faults, our study suggests that the south-southeastward motion of the Chuan-Dian block is likely to be firstly accommodated in part by the right-lateral shear and dip-slip motions of the Qujiang and Shiping faults and continues across the Red River fault zone, then is transmitted southward along the Dien Bien Phu fault. Therefore, the southern segment of the XJFZ plays a dominant role in the tectonic deformation of the southeastern Chuan-Dian block, with a high seismic hazard.

EVIDENCE FOR AND AGAINST MID-CRUSTAL DETACHMENT HORIZONS BASED ON CA. 25 MYR OF HETEROGENEOUS TRANSPRESSION IN THE DENALI FAULT SYSTEM

2019 ◽  
Author(s):  
Trevor S. Waldien ◽  
◽  
Sarah M. Roeske ◽  
Jeffrey A. Benowitz ◽  
Daniel F. Stockli
Keyword(s):  
Fault System ◽  
Denali Fault

Tail asymptotics of an infinitely divisible space-time model with convolution equivalent Lévy measure

2021 ◽  
Vol 58 (1) ◽  
pp. 42-67 ◽  
Author(s):  
Mads Stehr ◽  
Anders Rønn-Nielsen
Keyword(s):  
Space Time ◽  
Time Interval ◽  
Lévy Measure ◽  
Infinitely Divisible ◽  
Time Model ◽  
Spatial Object ◽  
Tail Behaviour ◽  
Fixed Radius ◽  
The Right ◽  
Space Time Model

AbstractWe consider a space-time random field on ${{\mathbb{R}^d} \times {\mathbb{R}}}$ given as an integral of a kernel function with respect to a Lévy basis with a convolution equivalent Lévy measure. The field obeys causality in time and is thereby not continuous along the time axis. For a large class of such random fields we study the tail behaviour of certain functionals of the field. It turns out that the tail is asymptotically equivalent to the right tail of the underlying Lévy measure. Particular examples are the asymptotic probability that there is a time point and a rotation of a spatial object with fixed radius, in which the field exceeds the level x, and that there is a time interval and a rotation of a spatial object with fixed radius, in which the average of the field exceeds the level x.

scholarly journals Consecutive ruptures on a complex conjugate fault system during the 2018 Gulf of Alaska earthquake

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shinji Yamashita ◽  
Yuji Yagi ◽  
Ryo Okuwaki ◽  
Kousuke Shimizu ◽  
Ryoichiro Agata ◽  
...  
Keyword(s):  
Gulf Of Alaska ◽  
Source Model ◽  
Fault System ◽  
Complex Conjugate ◽  
Inversion Method ◽  
Fault Geometry ◽  
Conjugate System ◽  
Finite Fault Inversion ◽  
Finite Fault ◽  
Alaska Earthquake

AbstractWe developed a flexible finite-fault inversion method for teleseismic P waveforms to obtain a detailed rupture process of a complex multiple-fault earthquake. We estimate the distribution of potency-rate density tensors on an assumed model plane to clarify rupture evolution processes, including variations of fault geometry. We applied our method to the 23 January 2018 Gulf of Alaska earthquake by representing slip on a projected horizontal model plane at a depth of 33.6 km to fit the distribution of aftershocks occurring within one week of the mainshock. The obtained source model, which successfully explained the complex teleseismic P waveforms, shows that the 2018 earthquake ruptured a conjugate system of N-S and E-W faults. The spatiotemporal rupture evolution indicates irregular rupture behavior involving a multiple-shock sequence, which is likely associated with discontinuities in the fault geometry that originated from E-W sea-floor fracture zones and N-S plate-bending faults.

The connection between the «color revolutions» and the strategic doctrines of the United States (late 20th century — 2014)

2021 ◽  
Author(s):  
Anna Igorevna Filimonova
Keyword(s):  
United States ◽  
20Th Century ◽  
American Foreign Policy ◽  
Use Of Force ◽  
The United States ◽  
Time Interval ◽  
Late 20Th Century ◽  
The Us ◽  
Color Revolutions ◽  
The Right

After the collapse of the USSR, fundamentally new phenomena appeared on the world arena, which became a watershed separating the bipolar order from the monopolar order associated with the establishment of the US global hegemony. Such phenomena were the events that are most often called «revolutions» in connection with the scale of the changes being made — «velvet revolutions» in the former Eastern Bloc, as well as revolutions of a different type, which ended in a change in the current regimes with such serious consequences that we are also talking about revolutionary transformations. These are technologies of «color revolutions» that allow organizing artificial and seemingly spontaneous mass protests leading to the removal of the legitimate government operating in the country and, in fact, to the seizure of power by a pro-American forces that ensure the Westernization of the country and the implementation of "neoliberal modernization", which essentially means the opening of national markets and the provision of natural resources for the undivided use of the Western factor (TNC and TNB). «Color revolutions» are inseparable from the strategic documents of the United States, in which, from the end of the 20th century, even before the collapse of the USSR, two main tendencies were clearly traced: the expansion of the right to unilateral use of force up to a preemptive strike, which is inextricably linked with the ideological justification of «missionary» American foreign policy, and the right to «assess» the internal state of affairs in countries and change it to a «democratic format», that is, «democratization». «Color revolutions», although they are not directly mentioned in strategic documents, but, being a «technical package of actions», straightforwardly follow from the right, assigned to itself by Washington, to unilateral use of force, which is gradually expanding from exclusively military actions to a comprehensive impact on an opponent country, i.e. essentially a hybrid war. Thus, the «color revolutions» clearly fit into the strategic concept of Washington on the use of force across the entire spectrum (conventional and unconventional war) under the pretext of «democratization». The article examines the period of registration and expansion of the US right to use force (which, according to the current international law, is a crime without a statute of limitations) in the time interval from the end of the twentieth century until 2014, filling semantic content about the need for «democratic transformations» of other states, with which the United States approached the key point of the events of the «Arab spring» and «color revolutions» in the post-Soviet space, the last and most ambitious of which was the «Euromaidan» in Ukraine in 2014. The article presents the material for the preparation of lectures and seminars in the framework of the training fields «International Relations» and «Political Science».

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