New estimates of minimum geological convergence for the eastern Himalaya, India

We re-investigate the geological slip along the frontal Nameri Thrust, a local name for the Himalayan Frontal Thrust in the eastern Himalaya, India. Four levels of tectonically displaced and uplifted fluvial terraces preserved along the Kameng River were dated using the Optically Stimulated Luminescence (OSL) method. The OSL ages of the terraces bracket the timing of their abandonment post ~14, 11, 7.2 and 3 ka respectively. Considering the minimum timing of vertical uplift and height of the uplifted and incised bedrock strath beneath the lowermost river terrace T1, we use trigonometric method to infer a vertical uplift rate of ~0.44 mm/a on the Nameri Thrust during the Holocene Period. The mismatch in the geodetic convergence and the geological slip rates proposed for the Himalayan Frontal Thrust in the eastern Himalaya in earlier studies provoked us to re-evaluate the scenario of geological slip in the area. Our results suggest a contrasting estimate of geological slip rate as compared to the earlier studies. Though the results are indicative of a decrease in the Indo-Eurasian convergence in the eastern Himalaya in accordance with the recent GPS observations and models proposed for the region, we, however, suggest that the lower estimation in our study compared to that reported previously could be due to the use of different dating methods for the materials obtained for assigning chronology to the landforms and events. Since the 14C AMS radiocarbon dating method requires a contemporary organic component in the sediments to be dated, an overestimation of the dates is also possible if the sediment has mixed with old carbon, which makes it inferior to the OSL method in which the mineral grains are assumed to have been fully bleached before their burial. This makes the OSL method more reliable to date sediments since it does not encounter the &#8216;old-carbon&#8217; error problem of overestimation of the ages. Two additional samples obtained to the south of the active mountain front yield southwardly-increasing luminescence ages of ~19 and 26 ka suggesting deposition of older sediments toward downstream by the Kameng River as a result of rampant incision in the upstream triggered by episodes of tectonic uplift prior to ~26 ka.

Download Full-text

How to reconcile OSL and TCN data: the potential of high-resolution sampling on the Choushui Tableland (West Central Taiwan)

10.5194/egusphere-egu2020-4595 ◽

2020 ◽

Author(s):

Magali Rizza ◽

Brice Lebrun ◽

Lionel Siame ◽

Valéry Guillou

Keyword(s):

High Resolution ◽

Depth Profile ◽

Slip Rate ◽

Sampling Strategy ◽

Rock Surface ◽

Slip Rates ◽

Fluvial Terraces ◽

Dating Methods ◽

Central Taiwan ◽

Geomorphic Processes

The determination of fault slip rate is often inferred from dating of Quaternary, deformed geomorphological surfaces affected by fault activity. For this reason, cosmogenic and luminescence methods now are widely applied to date the emplacement of geomorphic markers, but each method relates to different geomorphic processes. While the Terrestrial Cosmogenic Nuclides (TCN) method generally dates the exposure duration of the rock surface to cosmic rays, the Optically Stimulated Luminescence (OSL) method provides burial duration of the sediment after deposition. Age differences between these two methods may relate to the erosion-transport-deposition and aggradation processes experienced by the sediment prior its final deposition but combined may provide new insights into the processes affecting alluvial landforms.Our case study is located in the Western Foothills, south of the Choushui River (Central Taiwan). There, slip on the Changhua blind thrust fault has caused the eastward tilt of a wide flight of fluvial terraces but slip rates on frontal faults are still debated due to large epistemic uncertainties in dating alluvial surfaces with OSL and TCN methods. To achieve a finer chronology of the deposits, a high-resolution sampling strategy has been deployed leading to a direct and unique comparison between OSL and TCN dating methods. Taking advantage of a natural exposure, we collected 10 samples for 10Be dating completed by 5 OSL samples along a 7 m depth profile. The depth distribution of 10Be concentrations show a complex depositional history with at least two depositional sequences, modelled to be older than ~38.7&#160;ka.As previous work has shown the difficulties of OSL dating in Taiwan, particular attention has been paid to luminescence characteristics of quartz and potential dosimetry issues. Our OSL analysis are in good agreement with 10Be and previous 14C dating and also reveal three depositional units, dated between ~9 ka and ~66 ka, that are evidenced by different OSL signal characteristics and variations in dosimetry.This study shows that it is informative to have an exhaustive, detailed, and direct comparison between dating methods on a single depth profile to discuss the geomorphic processes and allow a more detailed understanding of the long-term rates of the Changhua Fault.

Download Full-text

10Be exposure dating of river terraces at the southern mountain front of the Dzungarian Alatau (SE Kazakhstan) reveals rate of thrust faulting over the past ~ 400 ka

Quaternary Research ◽

10.1016/j.yqres.2013.10.016 ◽

2014 ◽

Vol 81 (1) ◽

pp. 168-178 ◽

Cited By ~ 14

Author(s):

Anja Cording ◽

Ralf Hetzel ◽

Martin Kober ◽

Jonas Kley

Keyword(s):

Slip Rate ◽

Thrust Fault ◽

Tien Shan ◽

Slip Rates ◽

Exposure Dating ◽

River Terraces ◽

Mountain Front ◽

Mountain Belts ◽

10Be Exposure Dating ◽

Age Constraints

AbstractThe mountain belts of the Dzungarian Alatau (SE Kazakhstan) and the Tien Shan are part of the actively deforming India–Asia collision zone but how the strain is partitioned on individual faults remains poorly known. Here we use terrace mapping, topographic profiling, and 10Be exposure dating to constrain the slip rate of the 160-km-long Usek thrust fault, which defines the southern front of the Dzungarian Alatau. In the eastern part of the fault, where the Usek River has formed five terraces (T1–T5), the Usek thrust fault has vertically displaced terrace T4 by 132 ± 10 m. At two sites on T4, exposure dating of boulders, amalgamated quartz pebbles, and sand from a depth profile yielded 10Be ages of 366 ± 60 ka and 360 + 77/− 48 ka (both calculated for an erosion rate of 0.5 mm/ka). Combined with the vertical offset and a 45–70° dip of the Usek fault, these age constraints result in vertical and horizontal slip rates of ~ 0.4 and ~ 0.25 mm/a, respectively. These rates are below the current resolution of GPS measurements and highlight the importance of determining slip rates for individual faults by dating deformed landforms to resolve the pattern of strain distribution across intracontinental mountain belts.

Download Full-text

Pliocene to Quaternary tectonics in the Horná Nitra Depression (Western Carpathians)

Geologica Carpathica ◽

10.2478/v10096-011-0028-5 ◽

2011 ◽

Vol 62 (4) ◽

pp. 381-393 ◽

Cited By ~ 13

Author(s):

Rastislav Vojtko ◽

Juraj Beták ◽

Jozef Hók ◽

František Marko ◽

Vojtech Gajdoš ◽

...

Keyword(s):

Active Fault ◽

Slip Rate ◽

Normal Fault ◽

Western Carpathians ◽

Early Pleistocene ◽

Tectonic Activity ◽

Slip Rates ◽

Compressional Stress ◽

Mountain Front ◽

Half Graben

Pliocene to Quaternary tectonics in the Horná Nitra Depression (Western Carpathians)The Horná Nitra Depression is an Upper Miocene-Quaternary intramontane sedimentary basin. This N-S elongated half-graben structure is rimmed from the west by the marginal Malá Magura fault which is the most distinctive fault in the Horná Nitra Depression, traditionally considered as an active fault during the neotectonic phase. This dislocation is attended by contrasting landforms and their parameters. The lowS-indexof about 1.10, at least two generations of well-preserved faceted slopes along this fault, and longitudinal river valley profiles point to the presence of a low-destructed actual mountain front line, which is typical for the Quaternary active fault systems. Comparison with known normal fault slip rates in the world makes it possible to set an approximate vertical slip rate between 0.3-1.1 m · kyr-1. The present-day fault activity is considered to be normal, steeply dipping towards the east according to structural and geophysical data. The NNW-SSE present-day tectonic maximum horizontal compressional stressSHand perpendicular minimum horizontal compressional stressShwas estimated in the Horná Nitra region. The Quaternary activity of the Malá Magura fault is characterized by irregular movement. Two stages of important tectonic activity along the fault were distinguished. The first stage was dated to the Early Pleistocene. The second stage of tectonic activity can by dated to the Late Pleistocene and Holocene. The Malá Magura fault is permeable for gases because the soil atmosphere above the ca. 150 meters wide fault zone contains increased contents of methane and radon.

Download Full-text

Variable Thrust Rates of the Eastern Qilianshan Mountain Front, Northeastern Margin of the Tibet Plateau and Its Implication to the Topography of the Yongchangnan Shan

Frontiers in Earth Science ◽

10.3389/feart.2021.622568 ◽

2021 ◽

Vol 9 ◽

Author(s):

Lei Jinghao ◽

Li Youli ◽

Ren Zhikun ◽

Hu Xiu ◽

Xiong Jianguo ◽

...

Keyword(s):

Slip Rate ◽

Strike Slip ◽

Tibet Plateau ◽

The Tibetan Plateau ◽

The West ◽

Slip Rates ◽

Study Region ◽

The North ◽

Mountain Front ◽

The Tibet Plateau

It is commonly assumed a thrust has a constant slip and uplifting rate along strike, however, this simplified model cannot always be consistent with field observations. The along strike slip patterns with variable offsets and rates contain plenty of information about the characteristics of the faulting behavior and its relationship with adjacent faults. The east Qilian Shan, located at the northeastern margin of the Tibetan Plateau, provides us an excellent opportunity to study the faulting behavior in a thrust-bounded range area. Besides the previously reported slip rates of the N-W trending tectonics across the region, we augmented the data by surveying the Fengle fault (FF), one of the north bounding thrusts of the Yongchangnan Shan. Another north bounding fault is the Kangningqiao Fault (KNF), east of the FF. Based on the vertical offsets and rates along the fault, we constructed the slip pattern along strike. The results show the vertical slip rate of the FF ranges from 0.7 ± 0.1 mm/a to 2.8 ± 1.3 mm/a across three surveyed sites. The slip rate decreases from the east to the west. The FF and KNF might be inferred as two segments of a single segmented thrust controlling the uplift of the Yongchangnan Shan. By comparing the uplift onsets in the study region, we discuss the northeastward propagated deformation along the northeastern margin of the Tibet plateau.

Download Full-text

Tire/Road Rolling Resistance Modeling: Discussing the Surface Macrotexture Effect

Coatings ◽

10.3390/coatings11050538 ◽

2021 ◽

Vol 11 (5) ◽

pp. 538

Author(s):

Malal Kane ◽

Ebrahim Riahi ◽

Minh-Tan Do

Keyword(s):

Slip Rate ◽

Rolling Resistance ◽

Friction Model ◽

Slip Rates ◽

Wide Range ◽

Road Surfaces ◽

Profile Depth ◽

Experimental Rolling ◽

Resistance Modeling ◽

Pavement Friction

This paper deals with the modeling of rolling resistance and the analysis of the effect of pavement texture. The Rolling Resistance Model (RRM) is a simplification of the no-slip rate of the Dynamic Friction Model (DFM) based on modeling tire/road contact and is intended to predict the tire/pavement friction at all slip rates. The experimental validation of this approach was performed using a machine simulating tires rolling on road surfaces. The tested pavement surfaces have a wide range of textures from smooth to macro-micro-rough, thus covering all the surfaces likely to be encountered on the roads. A comparison between the experimental rolling resistances and those predicted by the model shows a good correlation, with an R2 exceeding 0.8. A good correlation between the MPD (mean profile depth) of the surfaces and the rolling resistance is also shown. It is also noticed that a random distribution and pointed shape of the summits may also be an inconvenience concerning rolling resistance, thus leading to the conclusion that beyond the macrotexture, the positivity of the texture should also be taken into account. A possible simplification of the model by neglecting the damping part in the constitutive model of the rubber is also noted.

Download Full-text

A revised position for the primary strand of the Pleistocene-Holocene San Andreas fault in southern California

Science Advances ◽

10.1126/sciadv.aaz5691 ◽

2021 ◽

Vol 7 (13) ◽

pp. eaaz5691

Author(s):

Kimberly Blisniuk ◽

Katherine Scharer ◽

Warren D. Sharp ◽

Roland Burgmann ◽

Colin Amos ◽

...

Keyword(s):

Los Angeles ◽

Southern California ◽

San Andreas Fault ◽

Slip Rate ◽

Large Magnitude ◽

Slip Rates ◽

San Andreas ◽

The Pacific ◽

Large Earthquakes ◽

Dependent Probability

The San Andreas fault has the highest calculated time-dependent probability for large-magnitude earthquakes in southern California. However, where the fault is multistranded east of the Los Angeles metropolitan area, it has been uncertain which strand has the fastest slip rate and, therefore, which has the highest probability of a destructive earthquake. Reconstruction of offset Pleistocene-Holocene landforms dated using the uranium-thorium soil carbonate and beryllium-10 surface exposure techniques indicates slip rates of 24.1 ± 3 millimeter per year for the San Andreas fault, with 21.6 ± 2 and 2.5 ± 1 millimeters per year for the Mission Creek and Banning strands, respectively. These data establish the Mission Creek strand as the primary fault bounding the Pacific and North American plates at this latitude and imply that 6 to 9 meters of elastic strain has accumulated along the fault since the most recent surface-rupturing earthquake, highlighting the potential for large earthquakes along this strand.

Download Full-text

Complex Slip Distribution of the 2021 Mw 7.4 Maduo, China, Earthquake: An Event Occurring on the Slowly Slipping Fault

Seismological Research Letters ◽

10.1785/0220210226 ◽

2021 ◽

Author(s):

Rumeng Guo ◽

Hongfeng Yang ◽

Yu Li ◽

Yong Zheng ◽

Lupeng Zhang

Keyword(s):

Slip Rate ◽

Slip Distribution ◽

Seismic Gap ◽

Seismogenic Fault ◽

Coseismic Slip ◽

Slip Rates ◽

Kunlun Mountain ◽

Coulomb Failure ◽

Main Fault ◽

Large Earthquakes

Abstract The 21 May 2021 Maduo earthquake occurred on the Kunlun Mountain Pass–Jiangcuo fault (KMPJF), a seismogenic fault with no documented large earthquakes. To probe its kinematics, we first estimate the slip rates of the KMPJF and Tuosuo Lake segment (TLS, ∼75 km north of the KMPJF) of the East Kunlun fault (EKLF) based on the secular Global Positioning System (GPS) data using the Markov chain Monte Carlo method. Our model reveals that the slip rates of the KMPJF and TLS are 1.7 ± 0.8 and 7.1 ± 0.3 mm/yr, respectively. Then, we invert high-resolution GPS and Interferometric Synthetic Aperture Radar observations to decipher the fault geometry and detailed coseismic slip distribution associated with the Maduo earthquake. The geometry of the KMPFJ significantly varies along strike, composed of five fault subsegments. The most slip is accommodated by two steeply dipping fault segments, with the patch of large sinistral slip concentrated in the shallow depth on a simple straight structure. The released seismic moment is ∼1.5×1020 N·m, equivalent to an Mw 7.39 event, with a peak slip of ∼9.3 m. Combining the average coseismic slip and slip rate of the main fault, an earthquake recurrence period of ∼1250−400+1120 yr is estimated. The Maduo earthquake reminds us to reevaluate the potential of seismic gaps where slip rates are low. Based on our calculated Coulomb failure stress, the Maduo earthquake imposes positive stress on the Maqin–Maqu segment of the EKLF, a long-recognized seismic gap, implying that it may accelerate the occurrence of the next major event in this region.

Download Full-text

New geodetic constraints on southern San Andreas fault-slip rates, San Gorgonio Pass, California

Geosphere ◽

10.1130/ges02239.1 ◽

2020 ◽

Author(s):

Katherine A. Guns ◽

Richard A Bennett ◽

Joshua C. Spinler ◽

Sally F. McGill

Keyword(s):

Velocity Field ◽

Southern California ◽

San Andreas Fault ◽

Plate Boundary ◽

Slip Rate ◽

Fault Slip ◽

Slip Rates ◽

San Andreas ◽

Fault Slip Rates ◽

Gps Velocity Field

Assessing fault-slip rates in diffuse plate boundary systems such as the San Andreas fault in southern California is critical both to characterize seismic hazards and to understand how different fault strands work together to accommodate plate boundary motion. In places such as San Gorgonio Pass, the geometric complexity of numerous fault strands interacting in a small area adds an extra obstacle to understanding the rupture potential and behavior of each individual fault. To better understand partitioning of fault-slip rates in this region, we build a new set of elastic fault-block models that test 16 different model fault geometries for the area. These models build on previous studies by incorporating updated campaign GPS measurements from the San Bernardino Mountains and Eastern Transverse Ranges into a newly calculated GPS velocity field that has been removed of long- and short-term postseismic displacements from 12 past large-magnitude earthquakes to estimate model fault-slip rates. Using this postseismic-reduced GPS velocity field produces a best- fitting model geometry that resolves the long-standing geologic-geodetic slip-rate discrepancy in the Eastern California shear zone when off-fault deformation is taken into account, yielding a summed slip rate of 7.2 ± 2.8 mm/yr. Our models indicate that two active strands of the San Andreas system in San Gorgonio Pass are needed to produce sufficiently low geodetic dextral slip rates to match geologic observations. Lastly, results suggest that postseismic deformation may have more of a role to play in affecting the loading of faults in southern California than previously thought.

Download Full-text