The Longriqu fault zone, eastern Tibetan Plateau: Segmentation and Holocene behavior

Ansberque, Claire; Bellier, Olivier; Godard, Vincent; Lasserre, Cécile; Wang, Mingming; Braucher, Régis; Talon, Brigitte; Sigoyer, Julia de; Xu, Xiwei; Bourlès, Didier

doi:10.1002/2015tc004070

Cited by 21 publications

(19 citation statements)

References 80 publications

(162 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Morphotectonics analysis on the Boconó fault geometry, segmentation, and geomorphology allows us to identify 18 segments as well as several and truncated parallel traces (Figures S2 and S3). This puts in evidence a fault immaturity [ Manighetti et al ., ; Ansberque et al ., ]. The passive clockwise rotation of catchments in the Sierra de Aroa is similar to catchment geometries (in terms of topographic elevation and rotation) along the right strike‐slip faults of the Southern Alps in New Zealand, modeled by Castelltort et al .…”

Section: Discussionsupporting

confidence: 53%

Pleistocene slip rates on the Boconó fault along the North Andean Block plate boundary, Venezuela

et al. 2017

View full text Add to dashboard Cite

The Boconó fault is a strike‐slip fault lying between the North Andean Block and the South American plate which has triggered at least five Mw > 7 historical earthquakes in Venezuela. The North Andean Block is currently moving toward NNE with respect to a stable South American plate. This relative displacement at ~12 mm yr−1 in Venezuela (within the Maracaibo Block) was measured by geodesy, but until now the distribution and rates of Quaternary deformation have remained partially unclear. We used two alluvial fans offset by the Boconó fault (Yaracuy Valley) to quantify slip rates, by combining 10Be cosmogenic dating with measurements of tectonic displacements on high‐resolution satellite images (Pleiades). Based upon a fan dated at >79 ka and offset by 1350–1580 m and a second fan dated at 120–273 ka and offset by 1236–1500 m, we obtained two Pleistocene rates of 5.0–11.2 and <20.0 mm yr−1, consistent with the regional geodesy. This indicates that the Boconó fault in the Yaracuy Valley accommodates 40 to 100% of the deformation between the South American plate and the Maracaibo Block. As no aseismic deformation was shown by interferometric synthetic aperture radar analysis, we assume that the fault is locked since the 1812 event. This implies that there is a slip deficit in the Yaracuy Valley since the last earthquake ranging from ~1 to 4 m, corresponding to a Mw 7–7.6 earthquake. This magnitude is comparable to the 1812 earthquake and to other historical events along the Boconó fault.

show abstract

Section: Discussionsupporting

confidence: 53%

Pleistocene slip rates on the Boconó fault along the North Andean Block plate boundary, Venezuela

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Yet the activity of the LFS has only been only documented so far for the Quaternary, but no data exist for its longer‐term (Meso‐Cenozoic) activity. Since at least the late Pleistocene, the Longriqu and Maoergai faults are active with a dominant right‐lateral component (Ansberque et al, ; Ren, Xu, Yeats, Zhang, Ding, & Gong, ; Ren et al, ). The Maoergai and Longriqu faults have a Quaternary dextral slip rate of 0.7 to 2.1 mm/yr (from 21 to 9 ka, respectively; Ren, Xu, Yeats, Zhang, Ding, & Gong, ) for the first one and ~3.2 mm/yr for the second one (Ansberque et al, ).…”

Section: Geological Settingmentioning

confidence: 99%

“…Since at least the late Pleistocene, the Longriqu and Maoergai faults are active with a dominant right‐lateral component (Ansberque et al, ; Ren, Xu, Yeats, Zhang, Ding, & Gong, ; Ren et al, ). The Maoergai and Longriqu faults have a Quaternary dextral slip rate of 0.7 to 2.1 mm/yr (from 21 to 9 ka, respectively; Ren, Xu, Yeats, Zhang, Ding, & Gong, ) for the first one and ~3.2 mm/yr for the second one (Ansberque et al, ). No vertical motion has been documented on the Maoergai fault (Ren, Xu, Yeats, Zhang, Ding, & Gong, ), while the Longriqu fault accommodated ~0.1 mm/yr of reverse slip in the Holocene (Figure a, Ren et al, ; Xu et al, ).…”

Section: Geological Settingmentioning

confidence: 99%

“…This assumption implies an old age (Triassic) of this system. Yet the activity of the LFS has only been only documented so far for the Quaternary, but no data exist for its longer-term (Ansberque et al, 2016;Ren, Xu, Yeats, Zhang, Ding, & Gong, 2013;Ren et al, 2013a). The Maoergai and Longriqu faults have a Quaternary dextral slip rate of 0.7 to 2.1 mm/yr (from 21 to 9 ka, respectively; Ren, Xu, Yeats, Zhang, Ding, & Gong, 2013) for the first one and~3.2 mm/yr for the second one (Ansberque et al, 2016).…”

Section: Geological Settingmentioning

confidence: 99%

“…Second, the discovery of the Longriba fault system (LFS), located~200 km northwest and parallel to the Longmen Shan (Shen et al, 2009), has fostered new questions concerning the accommodation of longwavelength deformation across this part of the plateau (Figure 1a, Ansberque et al, 2015;Guo et al, 2013). The late Quaternary dextral strike-slip activity of the LFS has been demonstrated by paleoseismology and morphotectonic studies (Ansberque et al, 2016;Ren, Xu, Yeats, Zhang, Ding, & Gong, 2013, Ren et al, 2013a. Geodetic measurements provide evidence that the system partitions deformation at the scale of the entire margin with~5 mm/yr of right-lateral displacement (Shen et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Differential Exhumation Across the Longriba Fault System: Implications for the Eastern Tibetan Plateau

et al. 2018

Self Cite

View full text Add to dashboard Cite

The deformation processes at work across the eastern margin of the Tibetan Plateau remain controversial. The interpretation of its tectonic history is often polarized between two deformation models: ductile flow in the lower crust and shortening and crustal thickening accommodated by brittle structures in the upper crust. Many geological investigations on this plateau margin focused on the Longmen Shan, at the western edge of the Sichuan Basin. However, the Longriba fault system (LFS) located 200 km northwest and parallel to the Longmen Shan structures provides an opportunity to understand the role of hinterland faults in eastern Tibet geodynamics. For this reason, we investigate the exhumation history of rocks across the LFS using (U‐Th)/He and fission track ages from apatite and zircon. Results show a significant contrast in cooling histories across the Maoergai fault, the southernmost fault of the LFS. South of the Maoergai fault, the bedrock records a rapid increase in exhumation rate since ~10–15 Ma. In contrast, the area north of the fault has experienced steady cooling since ~25–35 Ma. We attribute this cooling contrast to ~2 km of differential rock uplift across the Maoergai fault, providing the first evidence of activity of the LFS in the Late Cenozoic. Our results indicate that deformation of the eastern Tibetan margin has been partitioned into the LFS and the Longmen Shan over an ~200 km wide block, which should be incorporated in future studies on the region's deformation, and in both above‐mentioned deformation models.

show abstract

“3D_Fault_Offsets,” a Matlab Code to Automatically Measure Lateral and Vertical Fault Offsets in Topographic Data: Application to San Andreas, Owens Valley, and Hope Faults

et al. 2018

View full text Add to dashboard Cite

Measuring fault offsets preserved at the ground surface is of primary importance to recover earthquake and long‐term slip distributions and understand fault mechanics. The recent explosion of high‐resolution topographic data, such as Lidar and photogrammetric digital elevation models, offers an unprecedented opportunity to measure dense collections of fault offsets. We have developed a new Matlab code, 3D_Fault_Offsets, to automate these measurements. In topographic data, 3D_Fault_Offsets mathematically identifies and represents nine of the most prominent geometric characteristics of common sublinear markers along faults (especially strike slip) in 3‐D, such as the streambed (minimum elevation), top, free face and base of channel banks or scarps (minimum Laplacian, maximum gradient, and maximum Laplacian), and ridges (maximum elevation). By calculating best fit lines through the nine point clouds on either side of the fault, the code computes the lateral and vertical offsets between the piercing points of these lines onto the fault plane, providing nine lateral and nine vertical offset measures per marker. Through a Monte Carlo approach, the code calculates the total uncertainty on each offset. It then provides tools to statistically analyze the dense collection of measures and to reconstruct the prefaulted marker geometry in the horizontal and vertical planes. We applied 3D_Fault_Offsets to remeasure previously published offsets across 88 markers on the San Andreas, Owens Valley, and Hope faults. We obtained 5,454 lateral and vertical offset measures. These automatic measures compare well to prior ones, field and remote, while their rich record provides new insights on the preservation of fault displacements in the morphology.

show abstract

The Longriqu fault zone, eastern Tibetan Plateau: Segmentation and Holocene behavior

Cited by 21 publications

References 80 publications

Pleistocene slip rates on the Boconó fault along the North Andean Block plate boundary, Venezuela

Pleistocene slip rates on the Boconó fault along the North Andean Block plate boundary, Venezuela

Differential Exhumation Across the Longriba Fault System: Implications for the Eastern Tibetan Plateau

“3D_Fault_Offsets,” a Matlab Code to Automatically Measure Lateral and Vertical Fault Offsets in Topographic Data: Application to San Andreas, Owens Valley, and Hope Faults

Contact Info

Product

Resources

About