Active Faulting of Landforms along the Tuosuhu-Maoniushan Fault and Its Seismotectonic Implications in Eastern Qaidam Basin, China

2022 ◽  
Author(s):  
Guihua Chen ◽  
Xun Zeng ◽  
Zhongwu Li ◽  
Xiwei Xu
Keyword(s):  
Late Quaternary ◽  
Qaidam Basin ◽  
Slip Rate ◽  
Northern Margin ◽  
The North ◽  
Fold And Thrust Belt ◽  
Field Investigations ◽  
High Resolution Satellite Images ◽  
Geomorphic Features ◽  
Tectonic Belt

Abstract The fold-and-thrust belt along the northern margin of the Qaidam basin is a typical active tectonic belt located in the northeast Tibetan Plateau. This belt is at a high risk of strong earthquakes with magnitudes larger than 6, as shown by multiple recorded events during 1962–2009. The lack of detailed late Quaternary surficial faulting data and systematic seismotectonic studies has posed difficulties in properly assessing the seismic risks and understanding the ongoing geodynamics in this region. In this study, we mapped the geomorphic features and fault traces from high-resolution satellite images and field investigations of the Tuosuhu-Maoniushan fault (TMF). Field photogrammetry was conducted to obtain deformation measurements using a DJI M300 real-time kinematic (RTK) drone. The TMF displaces the Holocene and late Pleistocene alluvial terraces in the eastern Qaidam basin. This fault dips to the south in the west and central segments (as a boundary of the Denan depression) and to the north in the eastern segment along the piedmont of the Maoniushan Mountains. The vertical slip rate is estimated to be 0.37 ± 0.08 mm/yr, which is similar to that of the active southern Zongwulongshan fault. By integrating our investigations with the previously published studies on deep structures and Cenozoic geology of the region, we propose a deep-seated thrust model for the seismotectonics of the northern margin of the Qaidam basin. The Aimunike, Tuosuhu-Maoniushan, southern Zongwulongshan, and Zongwulong faults, along with many folds, form an active compressional zone. The complex across-strike structures and along-strike segmentation could facilitate the release of strain through earthquakes of magnitude 6–7 in this broad seismotectonics belt, rather than through strong surface-rupturing events resulting from a single mature large fault.

scholarly journals The Subsurface Geology and Landscape Evolution of the Volturno Coastal Plain, Italy: Interplay between Tectonics and Sea-Level Changes during the Quaternary

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3386
Author(s):  
Giuseppe Corrado ◽  
Sabrina Amodio ◽  
Pietro P. C. Aucelli ◽  
Gerardo Pappone ◽  
Marcello Schiattarella
Keyword(s):  
Cross Sections ◽  
Coastal Plain ◽  
Late Quaternary ◽  
Slip Rate ◽  
Tectonic Activity ◽  
Paleoenvironmental Reconstruction ◽  
Sea Level Changes ◽  
Plan View ◽  
North West ◽  
The North

The Volturno alluvial-coastal plain is a relevant feature of the Tyrrhenian side of southern Italy. Its plan-view squared shape is due to Pliocene-Quaternary block-faulting of the western flank of the south-Apennines chain. On the basis of the stratigraphic analysis of almost 700 borehole logs and new geomorphological survey, an accurate paleoenvironmental reconstruction before and after the Campania Ignimbrite (CI; about 40 ky) eruption is here presented. Tectonics and eustatic forcing have been both taken into account to completely picture the evolution of the coastal plain during Late Quaternary times. The upper Pleistocene-Holocene infill of the Volturno plain has been here re-organized in a new stratigraphic framework, which includes seven depositional units. Structural analysis showed that two sets of faults displaced the CI, so accounting for recent tectonic activity. Yet Late Quaternary tectonics is rather mild, as evidenced by the decametric vertical separations operated by those faults. The average slip rate, which would represent the tectonic subsidence rate of the plain, is about 0.5 mm/year. A grid of cross sections shows the stratigraphic architecture which resulted from interactions among eustatic changes, tectonics and sedimentary input variations. On the basis of boreholes analysis, the trend of the CI roof was reconstructed. An asymmetrical shape of its ancient morphology—with a steeper slope toward the north-west border—and the lack of coincidence between the present course of the Volturno River and the main buried bedrock incision, are significant achievements of this study. Finally, the morpho-evolutionary path of the Volturno plain has been discussed.

Spatio-temporal behaviour of continental transform faults: implications from the late Quaternary slip history of the North Anatolian Fault, Turkey

2019 ◽  
Vol 56 (11) ◽  
pp. 1218-1238 ◽  
Author(s):  
Cengiz Zabcı
Keyword(s):  
Shear Zone ◽  
Late Quaternary ◽  
Slip Rate ◽  
Secondary Structures ◽  
North Anatolian Fault ◽  
Marmara Region ◽  
Temporal Behaviour ◽  
The North ◽  
Slip History ◽  
History Of

The slip history of the North Anatolian Fault (NAF) is constrained by displacement and age data for the last 550 ka. First, I classified all available geological estimates as members of three groups: Model I for the eastern, Model II for the central, and Model III for the western segments where the North Anatolian Shear Zone gradually widens from east to west. The short-term uniform slip solutions yield similar results, 17.5 +4/–3.5 mm/a, 18.9 +3.7/–3.3 mm/a, and 16.9 +1.2/–1.1 mm/a from east to the west. Although these model rates do not show any significant spatial variations among themselves, the correlation with geodetic estimates, ranging between 15 mm/a and 28 mm/a for different sections of the NAF, displays significant discrepancies especially for the central and western segments of the fault. Discrepancies suggest that most strain is accumulated along the NAF, but some portion of it is distributed along secondary structures of the North Anatolian Shear Zone. The deformation rate is constant at least for the last 195 ka, whereas the limited number of data show strain transfer from northern to the southern strand between 195 and 320 ka BP in the Marmara Region when the incremental slip rate decreases to 13.2 +3.1/–2.9 mm/a for the northern strand of the NAF. Considering the possible uncertainties of incremental displacements and their timings, more studies on slip rate are needed at different sites, including major structural elements of the North Anatolian Shear Zone. Although most of the strain is localized along the main displacement zone, the NAF, secondary structures are still capable of generating earthquakes that can hardly reach Mw 7.

scholarly journals Steady late quaternary slip rate on the Cinarcik section of the North Anatolian fault near Istanbul, Turkey

2013 ◽  
Vol 40 (17) ◽  
pp. 4555-4559 ◽  
Author(s):  
Hulya Kurt ◽  
C. C. Sorlien ◽  
L. Seeber ◽  
M. S. Steckler ◽  
D. J. Shillington ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Slip Rate ◽  
North Anatolian Fault ◽  
The North

scholarly journals Incipient evolution of the Eastern California shear zone through the transpressional zone of the San Bernardino Mountains and San Gorgonio Pass, California

Geosphere ◽  
2020 ◽  
Vol 16 (4) ◽  
pp. 919-935
Author(s):  
William J. Cochran ◽  
James A. Spotila ◽  
Philip S. Prince
Keyword(s):  
Shear Zone ◽  
Slip Rate ◽  
San Bernardino Mountains ◽  
Eastern California Shear Zone ◽  
The North ◽  
San Bernardino ◽  
Geomorphic Features ◽  
Aerial Vehicle ◽  
Mountainous Landscape ◽  
High Topography

Abstract The nature of the connection between the Eastern California shear zone (ECSZ) and the San Andreas fault (SAF) in southern California (western United States) is not well understood. Northwest of San Gorgonio Pass, strands of the ECSZ may be migrating south and west into the convergent zone of the San Bernardino Mountains (SBM) as it is advected to the southeast via the SAF. Using high-resolution topography and field mapping, this study aims to test whether diffuse faults within the SBM represent a nascent connection between the ECSZ and the SAF. Topographic resolution of ≤1 m was achieved using both lidar and unmanned aerial vehicle surveys along two Quaternary strike-slip faults. The Lone Valley fault enters the SBM from the north and may form an along-strike continuation of the Helendale fault. We find that its geomorphic expression is obscured where it crosses Quaternary alluvium, however, suggesting that it may have a low rate of yet-undetermined activity. The Lake Peak fault is located farther south and cuts through the high topography of the San Gorgonio massif and may merge with strands of the SAF system. We find that this fault clearly cuts Quaternary glacial deposits, although the magnitude of offset is difficult to assess. Based on our interpretation of geomorphic features, we propose that the Lake Peak fault has predominantly dextral or oblique-dextral motion, possibly with a slip rate that is comparable to the low rates observed along other strands of the ECSZ (i.e., ≤1 mm/yr). Comparing the geomorphic expressions of these faults is difficult, however, given that the erosive nature of the mountainous landscape in the SBM may obscure evidence of active faulting. Based on these observations, as well as the occurrence of other diffuse faults in the region, we suggest that dextral strain is overprinting the actively convergent zone of the SBM, thereby creating a throughgoing connection between the ECSZ and the SAF west of San Gorgonio Pass.

scholarly journals Neotectonics, Kinematics, and Evolution of the Vernon, Awatere, and Cloudy Faults of the Marlborough Fault System, New Zealand

2021 ◽  
Author(s):  
◽  
Timothy David Bartholomew
Keyword(s):  
Late Quaternary ◽  
Normal Component ◽  
Slip Rate ◽  
Vertical Axis ◽  
Fault System ◽  
Clockwise Rotation ◽  
The North ◽  
Fault Network ◽  
Seismic Lines ◽  
Good Agreement

<p>The coastal Awatere, Vernon, and Cloudy faults are bent and mutually intersecting, forming a complexly deforming dextral-oblique fault network. To try to explain the kinematic, paleoseismic and evolutionary complexities of this network, I present the results of an investigation into the rates, timing, and direction of slip on the faults within the network; which bifurcate eastwards from the central Awatere fault at the northeast end of the Marlborough Fault System. Displacements of dated and nondated late Quaternary features by the three faults were measured both onshore and offshore, constraining the kinematics of the fault network. The Vernon fault oddly maintains a dextral-reverse structure although it varies over 90° in strike and the Cloudy and coastal Awatere faults change from nearly pure strike slip to having a normal component eastwards. These data indicate that the fault-bounded blocks between the coastal Awatere, Vernon and Cloudy faults are rotating anticlockwise about a vertical axis relative to the block to the north of the fault system. Slip-rate data also indicate that of the 6 ± 1 mm/yr of slip on the central Awatere Fault, 1.1 ± 0.6 mm/yr has been partitioned ENE onto the coastal Awatere Fault and <4.9 mm/yr has been partitioned NNE onto the Vernon Fault. A slip-rate shortage in the splays of the Vernon Fault in the Vernon Hills is caused by a combination of unsighted faults and rotation of smaller splay-bounded blocks within the Vernon Hills. Paleoseismic records on the Vernon Fault were analysed onshore in a trench and offshore on seismic lines, with the records in good agreement. 3-5 earthquakes are recognised at different sites, with the last earthquake occurring 3.3 ka and a mean recurrence interval of 3-4 ka on the Vernon Fault. When combined with the paleseismic records from the Awatere and Cloudy faults I find that separate faults ruptured at similar times, suggesting a connectivity of the faults, as separate faults could mutually rupture during one earthquake or an earthquake could subsequently trigger an earthquake on a nearby fault. Finally I present the finite slip of geologic units and use these data as well as the late Quaternary slip data to describe the evolution of the fault network. I propose that the fault network at the NE end of the Awatere fault has stepped northwards into several splays, caused by clockwise rotation of the NE tips of the Marlborough faults.</p>

Coseismic surface rupture during the 2018 Mw 7.5 Palu earthquake, Sulawesi Island, Indonesia

2020 ◽  
Author(s):  
Dengyun Wu ◽  
Zhikun Ren ◽  
Jinrui Liu ◽  
Jie Chen ◽  
Peng Guo ◽  
...  
Keyword(s):  
Slip Rate ◽  
Flower Structure ◽  
Surface Rupture ◽  
Sand Liquefaction ◽  
Field Surveys ◽  
The North ◽  
Field Investigations ◽  
Surface Ruptures ◽  
Lateral Offset ◽  
Coseismic Offset

Sulawesi Island is located at the triple junction between the converging Australian, Sunda, and Philippine plates. The magnitude (Mw) 7.5 Palu earthquake occurred on 28 September 2018 on Sulawesi Island and caused serious casualties. The causative fault of the Palu earthquake was the left-lateral, strike-slip Palu-Koro fault, which has a rapid slip rate. We experienced this earthquake in Palu City and conducted field investigations on coseismic surface ruptures 1 d after the earthquake. Field surveys revealed that the coseismic surface ruptures were characterized by left-lateral offset, en echelon tensional cracks, mole tracks within a narrow zone, and large areas of sand liquefaction that increased the damage and losses. We measured the coseismic displacements along surface ruptures and observed a maximum coseismic offset of ∼6.2 m. The rupture traces in the north Palu Basin near Palu City mark the previously unmapped Palu-Koro fault. Based on the field investigations, we determined the exact location of the Palu-Koro fault within the Palu Basin and found that the Palu-Koro fault zone can be divided into three branches: F1, F2, and F3, forming a typical flower structure.

Holocene slip rate of the frontal thrust in the western Qilian Shan, NE Tibetan Plateau

2019 ◽  
Vol 219 (2) ◽  
pp. 853-865
Author(s):  
Xingwang Liu ◽  
Daoyang Yuan ◽  
Wenjun Zheng ◽  
Yanxiu Shao ◽  
Bingxu Liu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Slip Rate ◽  
Slip Rates ◽  
Northern Margin ◽  
Field Investigations ◽  
Western Segment ◽  
Aerial Vehicle ◽  
High Resolution Satellite Imagery ◽  
Fault Scarps ◽  
Geomorphic Surfaces

SUMMARY The activities of frontal thrusts in the northern Qilian Shan are critical for understanding the deformation of the Qilian Shan and the northeastern Tibetan Plateau. In this study, we estimate the slip rate of the active Fodongmiao–Hongyazi thrust along the northern margin of the Qilian Shan. High-resolution satellite imagery interpretations and detailed field investigations suggest that the fault displaced late Pleistocene terraces and formed fresh prominent north-facing fault scarps. To quantify the slip rate of the fault, we measured the displacements along the fault scarps using an unmanned aerial vehicle system and dated the displaced geomorphic surfaces using optically stimulated luminescence (OSL) and 14C methods. The vertical slip rate of the fault is estimated at 1.0 ± 0.3 mm yr−1 for the western segment. The slip rates for two branches in the eastern segment are 0.3 ± 0.1 and 0.6 ± 0.1 mm yr−1. Using a fault dip of 40 ± 10°, we constrain the corresponding shortening rates to 1.4 ± 0.5 and 1.2 ± 0.4 mm yr−1, respectively. The rates are consistent with values over different timescales, which suggests steady rock uplift and northeastward growth of the western Qilian Shan. Crustal shortening occurs mainly on the range-bounding frontal thrust.

scholarly journals Neotectonics, Kinematics, and Evolution of the Vernon, Awatere, and Cloudy Faults of the Marlborough Fault System, New Zealand

2021 ◽  
Author(s):  
◽  
Timothy David Bartholomew
Keyword(s):  
Late Quaternary ◽  
Normal Component ◽  
Slip Rate ◽  
Vertical Axis ◽  
Fault System ◽  
Clockwise Rotation ◽  
The North ◽  
Fault Network ◽  
Seismic Lines ◽  
Good Agreement

<p>The coastal Awatere, Vernon, and Cloudy faults are bent and mutually intersecting, forming a complexly deforming dextral-oblique fault network. To try to explain the kinematic, paleoseismic and evolutionary complexities of this network, I present the results of an investigation into the rates, timing, and direction of slip on the faults within the network; which bifurcate eastwards from the central Awatere fault at the northeast end of the Marlborough Fault System. Displacements of dated and nondated late Quaternary features by the three faults were measured both onshore and offshore, constraining the kinematics of the fault network. The Vernon fault oddly maintains a dextral-reverse structure although it varies over 90° in strike and the Cloudy and coastal Awatere faults change from nearly pure strike slip to having a normal component eastwards. These data indicate that the fault-bounded blocks between the coastal Awatere, Vernon and Cloudy faults are rotating anticlockwise about a vertical axis relative to the block to the north of the fault system. Slip-rate data also indicate that of the 6 ± 1 mm/yr of slip on the central Awatere Fault, 1.1 ± 0.6 mm/yr has been partitioned ENE onto the coastal Awatere Fault and <4.9 mm/yr has been partitioned NNE onto the Vernon Fault. A slip-rate shortage in the splays of the Vernon Fault in the Vernon Hills is caused by a combination of unsighted faults and rotation of smaller splay-bounded blocks within the Vernon Hills. Paleoseismic records on the Vernon Fault were analysed onshore in a trench and offshore on seismic lines, with the records in good agreement. 3-5 earthquakes are recognised at different sites, with the last earthquake occurring 3.3 ka and a mean recurrence interval of 3-4 ka on the Vernon Fault. When combined with the paleseismic records from the Awatere and Cloudy faults I find that separate faults ruptured at similar times, suggesting a connectivity of the faults, as separate faults could mutually rupture during one earthquake or an earthquake could subsequently trigger an earthquake on a nearby fault. Finally I present the finite slip of geologic units and use these data as well as the late Quaternary slip data to describe the evolution of the fault network. I propose that the fault network at the NE end of the Awatere fault has stepped northwards into several splays, caused by clockwise rotation of the NE tips of the Marlborough faults.</p>

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