Strike-slip Rate Research Articles

Imaging underwater neotectonic structures in the Amazonian lowland

Previous documentation has proposed tectonic activity from the Neogene to Holocene as one important control on drainage development in the Amazonian lowland. However, recording tectonic structures in this region has been challenging due to environmental difficulties, including the low topography and dense vegetation cover that do not favor natural exposures. For this reason, the role of tectonics in determining river dynamics, morphology, and sediment deposition in Amazonia has been suggested with caution. Despite limitations, morphostructural lineaments have provided useful information to support fault reactivation in several areas of the Amazonian lowland. However, further documentation is required to map the faults and describe their geometry. This approach is essential to better understand the geotectonic model of this region. In this work, analyses of high-resolution optical imagery of three Amazonian shallow water lakes provided exceptional views of an abundance of linear features on the beds of these lakes. Although based on indirect evidence from remote sensing data, the quality of the images allowed the geometry of these underwater features to be characterized in detail. The most striking are sets of NE–SW lineaments that frequently intercept NW–SE trending lineaments with offsets of up to 500 m in the horizontal plane. These characteristics support dextral faults with strike–slip rates in the study areas. The faults display trends compatible with the geotectonic model proposed for the Brazilian Amazonia region. They also control the morphology of lakes and rivers, as indicated by the parallelism and/or continuity into straight lineaments that define lake margins and river courses, including the courses of large rivers, such as the Solimões and Amazonas Rivers. Available radiocarbon ages of deposits from the lake bed sediments and from related floodplain deposits are consistent with the proposal of faulting during the latest Holocene, even only a few hundred years ago.

Rates of geodetic deformation across active faults in southern Italy

Abstract Active deformation in southern Italy is accommodated by a distributed number of faults with low–moderate slip rates. Outcropping extensional faults and mostly blind transcurrent faults are mapped within a western (or axial) and an eastern domain, respectively. We use a combination of continuous (2001.00–2011.84) and episodic (1995.68–2010.79) GNSS observations to firstly estimate the geodetic deformation rate on 32 faults. Geodetic results were successively compared with geological displacement estimates. In agreement with seismological and geological information, a net spatial segregation emerges between the extensional axial belt, and the eastern domain where strike–slip faults are geodetically active. Although uncertainties are at times large, average displacement rates show broadly consistent patterns within both domains. A longitudinal gradient in extension rate is observed for the axial fault array, with two sectors of higher magnitude (~ 0.8–1.7 mm/yr for individual faults). This result is consistent with geological observations and supports the notion that extension occurs in discrete patches. Faults of the eastern domain have lower (few 0.1 to ~ 1.2 mm/yr) strike–slip rates and an eastward-decreasing extensional component, but significant geodetic displacement is detected in areas lacking clear evidence of activity. Few faults with 1–2 mm/yr extension rate are locally found in the eastern domain, but, based on their limited length and on inconsistency with seismology and geology, they are considered as due to deep-seated gravitational spreading. For crustal faults, although geodetic slip and moment rates are larger than geological rates, the broad trend of long- to short-term rates is similar, indicating the feasibility of geodetic analysis to contribute estimating fault slip rate and testing tectonic models in the region. Whereas the western domain extension is thought to be controlled by potential energy related to the Tyrrhenian Moho uplift beneath the Apennines, strike–slip in the east is related to shear on inherited faults within the Adriatic crust.

New c. 270 kyr strike-slip and uplift rates for the southern Alpine Fault and implications for the New Zealand plate boundary

Along 100 km of the Alpine Fault, major valleys and glacial deposits can be matched across an 8000 m dextral offset. We use paleontologic and stratigraphic age constraints to date c. 270 ka marine sediments uplifted to 600 m elevation and overlying c. 270 ka glacial deposits related to the 8000 m dextral offset. These constraints yield a fault-proximal Australian plate uplift rate of 2.6 (−0.5/+0.4) mm/yr and an Alpine Fault dextral slip rate of 29.6 (−2.5/+4.5) mm/yr. Our rates resolve an apparent along-strike drop in strike-slip rate and instead support a relatively constant along-strike dextral slip rate of ∼28 mm/yr (∼80% of current Australian-Pacific plate boundary motion). We argue that the rate of dextral slip on the southern Alpine Fault has been relatively constant over the last ≥3.5 myr, and that ductile fault processes may rate-limit the fault from accommodating a progressively higher percentage of plate boundary motion through time (i.e., the fault reached maturity long ago). The spatiotemporally constant strike-slip rate of the southern Alpine Fault and a previously published paleoseismic record of near-regular earthquake recurrence both characterize the Alpine Fault as a mature plate boundary fault zone that behaves in a constant way with behavior predictable over timescales of thousands and hundreds of thousands of years.

Laterally propagating slow slip events in a rate and state friction model with a velocity‐weakening to velocity‐strengthening transition

We investigate the behavior of simulated slow slip events using a rate and state friction model that is steady state velocity weakening at low slip speeds but velocity strengthening at high slip speeds. Our simulations are on a one‐dimensional (line) fault, but we modify the elastic interactions to mimic the elongate geometry frequently observed in slow slip events. Simulations exhibit a number of small events as well as periodic large events. The large events propagate approximately steadily “along strike,” and stress and slip rate decay gradually behind the propagating front. Their recurrence intervals can be determined by considering what is essentially an energy balance requirement for long‐distance propagation. It is possible to choose the model parameters such that the simulated events have the stress drops, slip velocities, and propagation rates observed in Cascadia.

Albian syndepositional block rotation and its geological consequences, Basque–Cantabrian Basin (western Pyrenees)

AbstractStratigraphic, structural, palaeocurrent and palaeomagnetic analyses of Upper Albian deep-water deposits in and around the Deba block (Northern Iberia) are presented. Results indicate an anticlockwise vertical-axis rotation of this block by 35° during a maximum time span of c. 1 Ma (Late Albian intra-C. auritus ammonite Subzone). This Albian syndepositional block rotation is interpreted to be the consequence of the coeval activity of conjugate major sinistral strike-slip faults and minor (antithetic) dextral strike-slip faults, which border the Deba block. On the base of conservative estimations, a minimum block-rotation rate of 35° Ma−1 and a sinistral strike-slip rate of 1.2 km Ma−1 are calculated. As a consequence of the interaction of the rotated Deba block with adjacent non-rotated blocks, its corners experienced coeval transpressive (NW and SE corners) and transtensional deformations (SW and, possibly, NE corners). At the transtensional SW corner, two domal high-reflective seismic structures have been recorded and interpreted as high-level magmatic laccoliths. These magmatic intrusions triggered the development of a mineralizing hydrothermal system, which vented to the Late Albian seafloor warm to hot hydrocarbon-rich fluids. Vented hydrocarbon was generated from Albian organic-rich sediments by contact alteration with hydrothermal fluids.

Holocene paleoearthquakes of the Maoergai fault, eastern Tibet

Much work about fault activity and seismic hazard assessment has been conducted on major boundary faults of eastern Tibet, whereas seismic activity on faults between subblocks is poorly understood. The Maoergai fault, ~200km northwest of and parallel to the Longmen Shan, is the eastern branch of the Longriba fault zone that divides the Bayan Har block into the Aba and Longmen Shan subblocks. Field investigation indicates that the Maoergai fault is a purely right-lateral strike–slip fault active in the Late Quaternary. Our trenches, combined with radiocarbon dating and Bayesian analysis, show that three Holocene paleoearthquakes ruptured the Maoergai fault at ~8510±420, ~7100±70, and ~5170±80calyr BP, respectively. This suggests that the fault fits a cluster model with an average recurrence interval of ~1700years and has a high potential of large earthquakes (Mw ~7.2–7.4) in the near future. Our results also indicate that an apparent fault scarp on a sloping tread provides an alternative site for paleoseismic studies to determine coseismic horizontal displacement on a strike–slip fault, and using the age of the upper terrace to determine strike–slip rate by displaced terrace riser is probably closer to the true value in streams with insufficient capacities of lateral erosion. This study provides useful information for the earthquake risk and fault behavior in eastern Tibet.

Kinematic study at the junction of the East Anatolian fault and the Dead Sea fault from GPS measurements

The Hatay Triple Junction (HTJ) is a tectonically complex area located at the intersection between the left-lateral East Anatolian fault (EAF), the Cyprus subduction arc and the left-lateral Dead Sea fault (DSF) which is a transform boundary between the Arabian and Sinai plates as they converge toward Eurasia. Previous GPS studies indicate a left-lateral strike-slip rate across the DSF varying from 5mm/yr (along the southern part) to 2mm/yr (along the northern part) (Alchalbi et al., 2010; Gomez et al., 2007; Le Béon et al., 2008; Mahmoud et al., 2005; Al-Tarazi et al., 2011). In contrast, the EAF has a roughly constant velocity along strike estimated at 9.7+0.9mm/yr (Reilinger et al., 2006). The HTJ contains several well-identified active fault segments (DSF, EAF, Osmaniye fault, Karasu fault, Latakia fault, Jisr-al-shuggur fault, Idleb fault and Afrin fault) (Meghraoui et al., 2011), the fault-slip rates for which are poorly constrained.In order to constrain better the slip rate on faults, we established a network of 57 GPS sites in NW Syria and in SE Turkey. The first campaign was carried out in September 2009; a second took place in September and November 2010 and a third (only in Turkey) in September 2011. Although the velocity field vectors computed from the 2009, 2010 and 2011 measurements appear consistent with other local studies, the results are hampered by large uncertainties due to the short observation period. However, preliminary interpretations are consistent with decreasing velocity along the DSF from south to north reported previously.

Characteristics of the Late Quaternary right-lateral strike-slip movement of Bolokenu-Aqikekuduk fault in northern Tianshan Mountains, NW China

The characteristics of the Bolokenu-Aqikekuduk (Bo-A) fault, a right-lateral strike-slip fault that runs for more than 700 km long and obliquely cuts North Tianshan Mountains, are evaluated here based on remote sensing data, and through an analysis of the results from field investigations as well as climate-geomorphic events. The fault is composed of a western segment with a NW strike and an eastern segment with a NWW strike. The western segment is nearly 250 km long, extending northwestward into Kazakhstan with a right-lateral strike-slip rate of 5 mm/a. This domain consists of 4–5 rupture sections, with 3–4 deformation belts, caused by ancient or historical earthquakes, and suggesting the potential for the occurrence of further strong earthquakes (with M ≈ 7.5) in future. The eastern segment of the fault shows a right-lateral strike-slip rate of 1–1.4 mm/a, with the development of 3–4 deformation belts caused by ancient or historical earthquakes, and with a potential for future strong earthquake with M ≈ 7.0. A typical strain partitioning style in the compression area has developed between the intermontane Bo-A fault and the piedmont thrust structures of Northern Tianshan Mountains, under the effect of oblique compression, as indicated by the piedmont thrust structure and the strike-slip fault in the mountains.

Simulating the recent evolution of the southern big bend of the San Andreas fault, Southern California

[1] The southern big bend of the San Andreas fault has been interpreted to have successively abandoned two strands, the Mission Creek and Mill Creek strands of the San Andreas fault, during the past 1 Ma before taking up activity along its present-day configuration. This evolution is simulated within three-dimensional models to explore the hypothesis that fault systems evolve to increase mechanical efficiency. The three-dimensional boundary element method models are validated by comparison of modeled fault slip rates and uplift rates with geologic data. The model results match well the geologic strike-slip rates and uplift patterns. Overestimation of reverse slip rates along the northern San Bernardino Mountains may reflect model assumptions of fault geometry. The partitioning of slip among active faults changes between the three phases of southern San Andreas fault evolution revealing (1) a trade-off in strike-slip rates between the San Jacinto and San Andreas faults, (2) a trade-off between strike-slip rates on the San Andreas fault and reverse slip along faults associated with uplifting the San Bernardino Mountains, and (3) a trade-off in strike-slip rates along the San Andreas and strike-slip rates along the Eastern California Shear Zone. Mechanical efficiency of the entire model increases from the Mission Creek to Mill Creek fault configuration and decreases from the Mill Creek configuration to the present-day configuration. The decrease in mechanical efficiency with the transition to the present-day fault geometry may reflect gaps in our understanding of tectonic loading and/or fault geometry.

Uniform Strike-Slip Rate along the Xianshuihe-Xiaojiang Fault System and Its Implications for Active Tectonics in Southeastern Tibet

Abstract Recent studies on the Xianshuihe-Xiaojiang fault system suggest that the Late Quaternary strike-slip rate is approximately uniform along the entire length of the fault zone, about 15±2 mm/a. This approximately uniform strike slip rate strongly supports the clockwise rotation model of the southeastern Tibetan crust. By approximating the geometry of the arc-shaped Xianshuihe-Xiaojiang fault system as a portion of a small circle on a spherical Earth, the 15±2 mm/a strike slip rate corresponds to clockwise rotation of the Southeastern Tibetan Block at the (5.2±0.7)×10−7 deg/a angular velocity around the pole (21°N, 88°E) relative to the Northeast Tibetan Block. The approximately uniform strike slip rate along the Xianshuihe-Xiaojiang fault system also implies that the Longmenshan thrust zone is not active, or at least its activity has been very weak since the Late Quaternary. Moreover, the total offset along the Xianshuihe-Xiaojiang fault system suggests that the lateral extrusion of the Southeastern Tibetan Block relative to Northeastern Tibetan Block is about 160 km and 200–240 km relative to the Tarim-North China block. This amount of lateral extrusion of the Tibetan crust should have accommodated about 13–24% convergence between India and Eurasia based on mass balance calculations. Assuming that the slip rate of 15±2 mm/a is constant throughout the entire history of the Xianshuihe-Xiaojiang fault system, 11±1.5 Ma is needed for the Xianshuihe-Xiaojiang fault system to attain the 160 km of total offset. This implies that left-slip faulting on the Xianshuihe-Xiaojiang fault system might start at 11±1.5 Ma.

Structural Geometry and Slip of the Palos Verdes Fault, Southern California: Implications for Earthquake Hazards

Abstract The Palos Verdes fault (PVF) is an active structure in southern California comprised of several segments that together form a complex fault system. The fault has been active since the Miocene and is a major regional seismic source. Using marine petroleum industry seismic data, we define the geometry of the fault and offsets of Tertiary stratigraphic units that constrain the along strike segmentation and slip rates on the fault system. In San Pedro Bay, patterns of deformed stratigraphic units suggest a deep fault geometry that dips moderately to the southwest and was initially formed as a Miocene normal fault. Plio–Pleistocene transpression resulted in the reactivation of this normal fault and its subsequent inversion with oblique, right-lateral reverse displacement. To the south, the Lasuen Knoll segment dips steeply to the northeast and is not a reactivated Miocene-age structure but rather formed in middle Pliocene time. Plio–Pleistocene transpression has linked these and other segments together to form the currently active PVF system. The resulting complex fault geometry and slip patterns suggest that the PVF is a highly segmented fault, which may rupture in moderate-size earthquakes that involve individual segments or large events that are able to propagate across significant geometric discontinuities. Estimates of moment magnitudes based on empirical relationships with rupture (fault) area indicate the possibility of M w 6.6–6.9 earthquakes for single-segment ruptures and M w 7.1–7.3 multisegment ruptures, with recurrence intervals ranging from 181 to 534 yr. Given the high inferred slip rates on the fault and its proximity to the urban population, these events pose significant earthquake hazards to metropolitan Los Angeles.

San Andreas fault geometry through the San Gorgonio Pass, California

Three-dimensional numerical models are needed to investigate the role of nonvertical strike-slip fault segments on the deformation within restraining bends. Numerical models simulate geologic deformation of two alternative three-dimensional present-day configurations for the San Andreas fault through the restraining bend within the San Gorgonio Pass region (SGPR) in Southern California. Both models produce decreasing strike-slip rates southward along the San Bernardino strand of the San Andreas fault, similar to geologic data. The north-dipping San Andreas fault model better matches the available strike-slip data as well as the geologic uplift data for the southern San Bernardino Mountains than the vertical San Andreas fault model. We conclude that a north-dipping fault configuration is preferred for models of the San Andreas fault in the SGPR. The complexity of the active fault geometry at the SGPR promotes the transfer of strike slip from the San Andreas fault to the nearby but unconnected San Jacinto fault. Slip rates and uplift patterns are sensitive to fault geometry within strike-slip restraining bends.

Postglacial (after 20 ka) dextral slip rate of the offshore Alpine fault, New Zealand

Geological displacement rates for major plate boundary strike-slip faults have seldom been determined with precision from the marine environment. In this paper I present high-quality slip rates derived from the southern Alpine fault using multibeam bathymetric data and dated samples from the Fiordland continental margin. These rates are derived from dextral displacements of relict but well-preserved glacial geomorphology (moraines and outwash fans), interpreted to 17 (+2/−1, calendar) ka. The weighted mean slip rate is 27.2 (−3.0/+1.8) mm/yr on the shelf between Milford and George Sounds, increasing southward to 31.4 (−3.5/+2.1) mm/yr between Caswell and Doubtful Sounds, with uncertainties at the 95% confidence level. These offshore rates are higher than those from an adjacent 80-km-length section of the fault on land in south Westland, and are in good agreement with global positioning system data. The southern slip rates represent some of the highest strike-slip rates on Earth, and ~90% of the total plate motion in southern New Zealand. The southward increase in strike-slip rate on the Alpine fault occurs despite a southward reduction in Pacific-Australian relative plate motion rate and despite the prediction of southward-decreasing plate-parallel motion and southward-increasing normal convergence. The Fiordland region is thus an excellent example of geological strain being highly partitioned within an obliquely convergent plate boundary zone.

Nonuniform Slip Rate and Millennial Recurrence Interval of Large Earthquakes along the Eastern Segment of the Kunlun Fault, Northern Tibet

The Kunlun fault is a major, active, left-lateral strike-slip fault upon the Tibet Plateau. Analysis of the long-term behavior of the fault is important in understanding the tectonic behavior of strike-slip faults and in assessing the mode of continental deformation and nature of seismic hazards upon the Tibet Plateau. However, our knowledge of the paleoseismicity and seismic behavior of the Kunlun fault remains limited and controversial because of difficult access, lack of field data, and the low spatial density of modern monitoring instruments. This study involved field investigations, fault-trench excavations, and an analysis of remote sensing images of the eastern (Maqen-Maqu) segment of the Kunlun fault near the town of Maqu in Gansu Province, China, revealing systematic deflections of rivers and gullies and mole track structures along the fault. Trench excavations revealed horizons of fluvial sand–gravel and silt–soil deposits, containing organic soil and peat, deformed by and offset along the fault. Based on the distribution of faulted and unfaulted sediments, fault-related structures, and ![Graphic][1] age data, nine paleoseismic surface-faulting events are identified over the past 9000–10,000 yr, of which the youngest event is constrained to the past 1000–1500 yr. A millennial recurrence interval of large earthquakes is estimated with an average slip of ∼3 m. An average Holocene slip rate of 3 mm/yr is estimated for this portion of the Kunlun fault. These results, together with those of previous studies, demonstrate that the along strike-slip rate is nonuniform, diminishing toward the east at an average gradient of 1 mm/100 km. This is in contrast to previous findings that the slip rate along the Kunlun fault is uniform and on the order of 11.5±2 mm/yr. [1]: /embed/inline-graphic-1.gif

Discovery of the Longriba fault zone in eastern Bayan Har block, China and its tectonic implication

Re-measured GPS data have recently revealed that a broad NE trending dextral shear zone exists in the eastern Bayan Har block about 200 km northwest of the Longmenshan thrust on the eastern margin of the Qinghai-Tibet Plateau. The strain rate along this shear zone may reach up to 4–6 mm/a. Our interpretation of satellite images and field observations indicate that this dextral shear zone corresponds to a newly generated NE trending Longriba fault zone that has been ignored before. The northeast segment of the Longriba fault zone consists of two subparallel N54°±5°E trending branch faults about 30 km apart, and late Quaternary offset landforms are well developed along the strands of these two branch faults. The northern branch fault, the Longriqu fault, has relatively large reverse component, while the southern branch fault, the Maoergai fault, is a pure right-lateral strike slip fault. According to vector synthesizing principle, the average right-lateral strike slip rate along the Longriba fault zone in the late Quaternary is calculated to be 5.4±2.0 mm/a, the vertical slip rate to be 0.7 mm/a, and the rate of crustal shortening to be 0.55 mm/a. The discovery of the Longriba fault zone may provide a new insight into the tectonics and dynamics of the eastern margin of the Qinghai-Tibet Plateau. Taken the Longriba fault zone as a boundary, the Bayan Har block is divided into two sub-blocks: the Ahba sub-block in the west and the Longmenshan sub-block in the east. The shortening and uplifting of the Longmenshan sub-block as a whole reflects that both the Longmenshan thrust and Longriba fault zone are subordinated to a back propagated nappe tectonic system that was formed during the southeastward motion of the Bayan Har block owing to intense resistance of the South China block. This nappe tectonic system has become a boundary tectonic type of an active block supporting crustal deformation along the eastern margin of the Qinghai-Tibet Plateau from late Cenozoic till now. The Longriba fault zone is just an active fault zone newly-generated in late Quaternary along this tectonic system.

Newly-generated Daliangshan fault zone — Shortcutting on the central section of Xianshuihe-Xiaojiang fault system

The Daliangshan fault zone is the eastern branch in the central section of Xianshuihe-Xiaojiang fault system. It has been neglected for a long time, partly because of no destructive earthquake records along this fault zone. On the other hand, it is located on the remote and inaccessible plateau. So far it was excluded as part of the Xianshuihe-Xiaojiang fault system. Based on the interpretation of aerophotographs and field investigations, we document this fault zone in detail, and give an estimation of strike-slip rate about 3 mm/a in Late Quaternary together with age dating data. The results suggest that the Daliangshan fault zone is a newly-generated fault zone resulted from shortcutting in the central section of Xianshuihe-Xiaojiang fault system because of the clockwise rotation of the Southeastern Tibetan Crustal Block, which is bounded by the Xianshuihe-Xiaojiang fault system. Moreover, the shortcutting may make the Daliangshan fault zone replace the Anninghe and Zemuhe fault zones gradually, and finally, the later two fault zones will probably die out with the continuous clockwise rotation.

Late Quaternary activity and dextral strike-slip movement on the Karakax Fault Zone, northwest Tibet

Field observations and interpretations of satellite images reveal that the westernmost segment of the Altyn Tagh Fault (called Karakax Fault Zone) striking WNW located in the northwestern margin of the Tibetan Plateau has distinctive geomorphic and tectonic features indicative of right-lateral strike-slip fault in the Late Quaternary. South-flowing gullies and N–S-trending ridges are systematically deflected and offset by up to ~ 1250 m, and Late Pleistocene–Holocene alluvial fans and small gullies that incise south-sloping fans record dextral offset up to ~ 150 m along the fault zone. Fault scarps developed on alluvial fans vary in height from 1 to 24 m. Riedel composite fabrics of foliated cataclastic rocks including cataclasite and fault gouge developed in the shear zone indicate a principal right-lateral shear sense with a thrust component. Based on offset Late Quaternary alluvial fans, 14C ages and composite fabrics of cataclastic fault rocks, it is inferred that the average right-lateral strike-slip rate along the Karakax Fault Zone is ~ 9 mm/a in the Late Quaternary, with a vertical component of ~ 2 mm/a, and that a M 7.5 morphogenic earthquake occurred along this fault in 1902. We suggest that right-lateral slip in the Late Quaternary along the WNW-trending Karakax Fault Zone is caused by escape tectonics that accommodate north–south shortening of the western Tibetan Plateau due to ongoing northward penetration of the Indian plate into the Eurasian plate.

When the Kunlun fault began its left-lateral strike-slip faulting in the northern Tibet: Evidence from cumulative offsets of basement rocks and geomorphic features

Himalayan Journal of Sciences Vol.2(4) Special Issue 2004 pp. 132

Faulting on the Anninghe fault zone, Southwest China in Late Quaternary and its movement model

The Anninghe fault is one of the significant earthquake-generating fault zones in the Southwest China. Local historical record shows that a M≥7 strong earthquake occurred in the year of 1536. On the basis of the detailed air-photographic interpretation and field investigation, we have acquired the following knowledge: ➀ The average sinistral strike-slip rate since the Late Pleistocene is about 3∼7 mm/a; ➁ There is important reverse faulting along the fault zone besides the main left-lateral strike-slip motion, and the shortening rate across the Anninghe fault zone due to the reverse faulting is about 1.7∼4.0 mm/a. If the Xianshuihe fault zone is simply partitioned into the Anninghe and Daliangshan faults, we can also get a slip rate of 3∼7 mm/a along the Daliangshan fault zone, which is the same as that on the Anninghe fault zone. Moreover, on the basis of our field investigation and the latest knowledge concerning the active tectonics of Tibetan crust, we create a dynamic model for the Anninghe fault zone.

Late Quaternary activity of the Zemuhe and Xiaojiang faults in southwest China from geomorphological mapping

There has been limited detailed geomorphological research on the Kangding fault system, located along the eastern margin of the Tibetan Plateau, despite the system containing active faults with high slip rates. Fault-related landforms such as offset streams were mapped at selected sites along the Zemuhe and Xiaojiang faults in the central and southern sections of the Kangding fault system. The results permitted assessment of the mode and rate of late Quaternary fault movement based on more comprehensive information than used in previous studies. The left-lateral strike-slip of these faults reflects the large-scale clockwise rotation of the Southern Tibetan Plateau. The estimated strike-slip rate of the Zemuhe fault is ca. 5–9 mm yr − 1 , whereas that of the Xiaojiang fault is ca. 14–22 mm yr − 1 . These rates and the known slip rates of the adjacent faults indicate that, in the northern and southern sections of the Kangding fault system, the regional tectonic stress from the clockwise rotation has been released mainly along the major faults; whereas, the stress in the central section has been released by both fault movement and deformation in surrounding areas. The latter mechanism reflects a more complex geological structure in the central system of distinct thrusts and folds. Late Quaternary vertical deformation along the Zemuhe and Xiaojiang faults has mostly resulted from local stresses associated with strike-slip movement, although the Zemuhe fault has also undergone slow but consistent normal faulting since the early Quaternary due to its orientation oblique to the direction of the clockwise rotation.