Rupture Kinematics of the 11 January 2021 Mw 6.7 Hovsgol, Mongolia, Earthquake and Implications in the Western Baikal Rift Zone

2021 ◽  
Author(s):  
Gang Liu ◽  
Xuejun Qiao ◽  
Pengfei Yu ◽  
Yu Zhou ◽  
Bin Zhao ◽  
...  
Keyword(s):  
Baikal Rift Zone ◽  
Tien Shan ◽  
Deformation Pattern ◽  
Convergence Region ◽  
The North ◽  
Finite Fault Inversion ◽  
Teleseismic Data ◽  
Finite Fault ◽  
The Right ◽  
Rupture Kinematics

Abstract The Mongolia plateau is the farthest intracontinental region of the India–Eurasia collision and is a transition zone between north–south convergence to the south in the Tien Shan and northwest–southeast extension to the north in the Baikal rift. Mongolia has experienced four M 8 earthquakes since 1905, but due to limited observations, the mechanism of these strong earthquakes and regional tectonics are poorly understood. The 11 January 2021 Mw 6.7 Hovsgol, Mongolia, earthquake is the largest event that has occurred in the Hovsgol graben, which is noted for being the northernmost convergence region of the India–Eurasia collision and the youngest extension region of the Baikal rift. In this article, the coseismic displacements are retrieved by space geodesy for the first time in this region, providing good constraints for the deformation pattern. We use a finite-fault inversion of InSAR and teleseismic data, and a backprojection analysis to reveal the rupture kinematics of this event. The geometry of the Hovsgol fault is determined as east-dipping with a dip of 45°. The rupture process is characterized by a northwestward propagation with a moderate average rupture velocity of ∼2.0  km/s and a complex slip pattern composed of two major slip patches with dimensions of 40  km×20  km. The oblique slip, illustrated by predominate extension and significant dextral striking, confirms the right-lateral-striking faulting in the Hovsgol rift, which indicates that the eastwardly north–south convergence across the southwest segment of the Baikal rift has decreased.

scholarly journals THE 2014 MW 6.9 NORTH AEGEAN TROUGH (NAT) EARTHQUAKE: SEISMOLOGICAL AND GEODETIC EVIDENCE

2017 ◽  
Vol 50 (3) ◽  
pp. 1583
Author(s):  
V. Saltogianni ◽  
M. Gianniou ◽  
T. Taymaz ◽  
S. Yolsal-Çevikbilen ◽  
S. Stiros
Keyword(s):  
Broad Band ◽  
Strike Slip ◽  
Fault Geometry ◽  
Coseismic Slip ◽  
The North ◽  
Finite Fault Inversion ◽  
Seismological Data ◽  
Finite Fault ◽  
Slip History ◽  
North Aegean

A strong earthquake (Mw 6.9) on 24 May 2014 ruptured the North Aegean Trough (NAT) in Greece, west of the North Anatolian Fault Zone (NAFZ). In order to provide unbiased constrains of the rupture process and fault geometry of the earthquake, seismological and geodetic data were analyzed independently. First, based on teleseismic long-period P- and SH- waveforms a point-source solution yielded dominantly right-lateral strike-slip faulting mechanism. Furthermore, finite fault inversion of broad-band data revealed the slip history of the earthquake. Second, GPS slip vectors derived from 11 permanent GPS stations uniformly distributed around the meizoseismal area of the earthquake indicated significant horizontal coseismic slip. Inversion of GPS-derived displacements on the basis of Okada model and using the new TOPological INVersion (TOPINV) algorithm permitted to model a vertical strike slip fault, consistent with that derived from seismological data. Obtained results are consistent with the NAT structure and constrain well the fault geometry and the dynamics of the 2014 earthquake. The latter seems to fill a gap in seismicity along the NAT in the last 50 years, but seems not to have a direct relationship with the sequence of recent faulting farther east, along the NAFZ.

scholarly journals Construction of fault geometry by finite-fault inversion of teleseismic data

2020 ◽  
Author(s):  
Kousuke Shimizu ◽  
Yuji Yagi ◽  
Ryo Okuwaki ◽  
Yukitoshi Fukahata
Keyword(s):  
Fault Geometry ◽  
Finite Fault Inversion ◽  
Teleseismic Data ◽  
Finite Fault

Two main rupture stages during the 2018 magnitude 7.5 Sulawesi earthquake

2020 ◽  
Vol 221 (3) ◽  
pp. 1873-1882
Author(s):  
Qi Li ◽  
Bin Zhao ◽  
Kai Tan ◽  
Wenbin Xu
Keyword(s):  
Body Wave ◽  
Geographical Location ◽  
Strike Slip ◽  
Inversion Method ◽  
The North ◽  
Finite Fault Inversion ◽  
Strike Direction ◽  
Finite Fault ◽  
The Moment ◽  
North And South

SUMMARY On 28 September 2018, a Mw 7.5 strike-slip earthquake occurred in Sulawesi Island, Indonesia, and it unexpectedly triggered a tsunami. To clearly understand the spatiotemporal evolution process of source rupture, we collected the far-field body wave data and utilized the back-projection method together with finite fault inversion method to investigate the rupture kinematics of this earthquake. Results obtained with the two methods have good consistency and complementarity. We hold that the rupture expanded from the epicentre and propagated bilaterally towards the north and south along the strike direction during the first 24 s, and then to the south. Therefore, the whole rupture process consists of two main stages. For the second stage, the fault segment experienced most of the moment release between 0 and 15 km depth, while the fault plane tended to slip at greater depth (down to 20 km) in the first stage. The total length of the rupture was about 200 km and the seismic moment was ∼2.48 × 1020 Nm, which was equivalent to Mw 7.5. The surface rupture was evident and the maximum slip of 6.24 m was observed in the Palu basin, which was close to Palu city. The rupture was dominated by left-lateral strike-slip with both normal and thrust components as well. The normal slip exhibited in the shallow part of the fault on the north side of Palu bay together with the special geographical location of Palu bay likely favored tsunami genesis.

scholarly journals The 10 June 2012 MW 6.0 earthquake sequence in the easternmost end of the Hellenic arc.

2016 ◽  
Vol 47 (3) ◽  
pp. 1138
Author(s):  
A. Kiratzi ◽  
M. Aktar ◽  
N. Svigkas
Keyword(s):  
Moment Tensor ◽  
Strike Slip ◽  
Earthquake Sequence ◽  
Deformation Pattern ◽  
Slip Vector ◽  
Hellenic Arc ◽  
Finite Fault Inversion ◽  
Finite Fault ◽  
Dextral Strike Slip ◽  
Shed Light

The 10 June 2012 (UTC 12:44:17.3; lat. 36.441°N, long. 28.904°E, Mw6.0) earthquake sequence, 60 km to the west of Rodos Island, is studied, in an attempt to shed light to the obscure deformation pattern at the easternmost end of the Hellenic Arc. Moment tensor solutions for the mainshock and the strongest aftershocks revealed the operation of WNW-ESE dextral strike-slip faulting, with slip vector at~N295°E, approximately orthogonal to the GPS velocity vectors. The strike of the activated structure generally aligns with bathymetric linear escarpments observed in the region, bordering the eastern section of the Rodos basin. The best constrained focal depths are in the range 10 to 25 km, with the mainshock at the depth of 24 km.The slip model for the mainshock, obtained through a finite-fault inversion scheme, showed that slip was mainly concentrated in a single patch, with the locus of peak slip (~125 cm) located ~ 4km to the NW of the hypocenter. The sequence which lies in the western continuation of the Fethiye – Burdur sinistral strike-slip zone into theAegean Sea and Rodos basin, is not connected with activation of this zone. Its characteristics comply with the activation of a dextral strike-slip structure, oblique to this zone, which accommodates along – arc NE-SW extension. 

Investor-State Dispute Settlement under NAFTA Chapter 11: The Shape of Things to Come?

1998 ◽  
Vol 35 ◽  
pp. 263-290
Author(s):  
J. Anthony VanDuzer
Keyword(s):  
Free Trade Agreement ◽  
Dispute Settlement ◽  
Trade Agreement ◽  
Minimum Standards ◽  
The North ◽  
State Behaviour ◽  
Nafta Chapter 11 ◽  
To Come ◽  
The Right

SummaryRecently, there has been a proliferation of international agreements imposing minimum standards on states in respect of their treatment of foreign investors and allowing investors to initiate dispute settlement proceedings where a state violates these standards. Of greatest significance to Canada is Chapter 11 of the North American Free Trade Agreement, which provides both standards for state behaviour and the right to initiate binding arbitration. Since 1996, four cases have been brought under Chapter 11. This note describes the Chapter 11 process and suggests some of the issues that may arise as it is increasingly resorted to by investors.

Why Has There Been No People’s Power Rebellion in North Korea?

2018 ◽  
pp. 1-34
Author(s):  
Andrew Jackson
Keyword(s):  
Rural Areas ◽  
North Korea ◽  
Large Scale ◽  
Political Elite ◽  
Information Control ◽  
Al Jazeera ◽  
The North ◽  
New Information ◽  
Effective System ◽  
The Right

One scenario put forward by researchers, political commentators and journalists for the collapse of North Korea has been a People’s Power (or popular) rebellion. This paper analyses why no popular rebellion has occurred in the DPRK under Kim Jong Un. It challenges the assumption that popular rebellion would happen because of widespread anger caused by a greater awareness of superior economic conditions outside the DPRK. Using Jack Goldstone’s theoretical expla-nations for the outbreak of popular rebellion, and comparisons with the 1989 Romanian and 2010–11 Tunisian transitions, this paper argues that marketi-zation has led to a loosening of state ideological control and to an influx of infor-mation about conditions in the outside world. However, unlike the Tunisian transitions—in which a new information context shaped by social media, the Al-Jazeera network and an experience of protest helped create a sense of pan-Arab solidarity amongst Tunisians resisting their government—there has been no similar ideology unifying North Koreans against their regime. There is evidence of discontent in market unrest in the DPRK, although protests between 2011 and the present have mostly been in defense of the right of people to support themselves through private trade. North Koreans believe this right has been guaranteed, or at least tacitly condoned, by the Kim Jong Un government. There has not been any large-scale explosion of popular anger because the state has not attempted to crush market activities outright under Kim Jong Un. There are other reasons why no popular rebellion has occurred in the North. Unlike Tunisia, the DPRK lacks a dissident political elite capable of leading an opposition movement, and unlike Romania, the DPRK authorities have shown some flexibility in their anti-dissent strategies, taking a more tolerant approach to protests against economic issues. Reduced levels of violence during periods of unrest and an effective system of information control may have helped restrict the expansion of unrest beyond rural areas.

Traditionalism and politics: A case study of Northern Nigeria

1967 ◽  
Vol 2 (4) ◽  
pp. 509-524 ◽  
Author(s):  
B. J. O. Dudley
Keyword(s):  
Social Change ◽  
Local Government ◽  
Status Quo ◽  
Political Elite ◽  
High Time ◽  
The Political ◽  
Northern Nigeria ◽  
The North ◽  
The Right

In the debate on the Native Authority (Amendment) Law of 1955, the late Premier of the North, Sir Ahmadu Bello, Sardauna of Sokoto, replying to the demand that ‘it is high time in the development of local government systems in this Region that obsolete and undemocratic ways of appointing Emirs’ Councils should close’, commented that ‘the right traditions that we have gone away from are the cutting off of the hands of thieves, and that has caused a lot of thieving in this country. Why should we not be cutting (off) the hands of thieves in order to reduce thieving? That is logical and it is lawful in our tradition and custom here.’ This could be read as a defence against social change, a recrudescence of ‘barbarism’ after the inroads of pax Britannica, and a plea for the retention of the status quo and the entrenched privilege of the political elite.

Geodetic analysis of the tectonic crustal deformation pattern in the North Aegean Sea, Greece

2021 ◽  
Author(s):  
Ilias Lazos ◽  
Sotirios Sboras ◽  
Christos Pikridas ◽  
Spyros Pavlides ◽  
Alexandros Chatzipetros
Keyword(s):  
Crustal Deformation ◽  
Aegean Sea ◽  
Deformation Pattern ◽  
The North ◽  
North Aegean ◽  
North Aegean Sea

Present-day orogenic processes in the western Kalpin nappe explored by interseismic GNSS measurements and coseismic InSAR observations of the 2020 Mw 6.1 Kalpin event

2021 ◽  
Author(s):  
Ping He ◽  
Yangmao Wen ◽  
Shuiping Li ◽  
Kaihua Ding ◽  
Zhicai Li ◽  
...  
Keyword(s):  
Source Parameters ◽  
Satellite System ◽  
Tien Shan ◽  
Dislocation Model ◽  
Maximum Displacement ◽  
Finite Fault ◽  
Instantaneous Deformation ◽  
Gnss Measurements ◽  
Global Navigation Satellite ◽  
Finite Fault Model

Summary As the largest and most active intracontinental orogenic belt on Earth, the Tien Shan (TS) is a natural laboratory for understanding the Cenozoic orogenic processes driven by the India-Asia collision. On 19 January 2020, a Mw 6.1 event stuck the Kalpin region, where the southern frontal TS interacts with the Tarim basin. To probe the local ongoing orogenic processes and potential seismic hazard in the Kalpin region, both interseismic and instantaneous deformation derived from geodetic observations are employed in this study. With the constraint of interseismic global navigation satellite system (GNSS) velocities, we estimate the décollement plane parameters of the western Kalpin nappe based on a two-dimensional dislocation model, and the results suggest that the décollement plane is nearly subhorizontal with a dip of ∼3° at a depth of 24 km. Then, we collect both Sentinel-1 and ALOS-2 satellite images to capture the coseismic displacements caused by the 2020 Kalpin event, and the interferometric synthetic aperture radar (InSAR) images show a maximum displacement of 7 cm in the line of sight near the epicentral region. With these coseismic displacement measurements, we invert the source parameters of this event using a finite-fault model. We determine the optimal source mechanism in which the fault geometry is dominated by thrust faulting with an E–W strike of 275° and a northward dip of 11.2°, and the main rupture slip is concentrated within an area 28.0 km in length and${\rm{\,\,}}$10.3 km in width, with a maximum slip of 0.3 m at a depth of 6–8 km. The total released moment of our preferred distributed slip model yields a geodetic moment of 1.59 × 1018 N$\cdot $m, equivalent to Mw 6.1. The contrast of the décollement plane depth from interseismic GNSS and the rupture depth from coseismic InSAR suggests that a compression still exists in the Kalpin nappe forefront, which is prone to frequent moderate events and may be at risk of a much more dangerous earthquake.

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.

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