[1] Using the measurements of $726 GPS stations around the Tibetan Plateau, we determine the rigid rotation of the entire plateau in a Eurasia-fixed reference frame which can be best described by an Euler vector of (24.38°± 0.42°N, 102.37°± 0.42°E, 0.7096°± 0.0206°/Ma). The rigid rotational component accommodates at least 50% of the northeastward thrust from India and dominates the eastward extrusion of the northern plateau. After removing the rigid rotation to highlight the interior deformation within the plateau, we find that the most remarkable interior deformation of the plateau is a ''glacier-like flow'' zone which starts at somewhere between the middle and western plateau, goes clockwise around the Eastern Himalayan Syntaxis (EHS), and ends at the southeast corner of the plateau with a fan-like front. The deformation feature of the southern plateau, especially the emergence of the flow zone could be attributed to an eastward escape of highly plastic upper crustal material driven by a lower crust viscous channel flow generated by lateral compression and gravitational buoyancy at the later developmental stage of the plateau. The first-order feature of crustal deformation of the northeastern plateau can be well explained by a three-dimensional elastic half-space dislocation model with rates of dislocation segments comparable to the ones from geological observations. In the eastern plateau, although GPS data show no significant convergence between the eastern margin of the plateau and the Sichuan Basin, a small but significant compressional strain rate component of $10.5 ± 2.8 nstrain/yr exists in a relatively narrow region around the eastern margin. In addition, a large part of the eastern plateau, northeast of the EHS, is not undergoing shortening along the northeastward convergence direction of the EHS but is stretching.

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China is a country of intense intracontinental seismicity. Most earthquakes in western China occur within the diffuse Indo-Eurasian plate-boundary zone, which extends thousands of kilometers into Asia. Earthquakes in eastern China mainly occur within the North China block, which is part of the Archean Sino-Korean craton that has been thermally rejuvenated since late Mesozoic. Here, we summarize neotectonic and geodetic results of crustal kinematics and explore their implications for geodynamics and seismicity using numerical modeling. Quaternary fault movements and global positioning system (GPS) measurements indicate a strong infl uence of the Indo-Asian collision on crustal motion in continental China. Using a spherical three-dimensional (3-D) fi nite-element model, we show that the effects of the collisional plate-boundary force are largely limited to western China, whereas gravitational spreading of the Tibetan Plateau has a broad impact on crustal deformation in much of Asia. The intense seismicity in the North China block, and the lack of seismicity in the South China block, may be explained primarily by the tectonic boundary conditions that produce high deviatoric stresses within the North China block but allow the South China block to move coherently as a rigid block. Within the North China block, seismicity is concentrated in the circum-Ordos rifts, refl ecting the control of lithospheric heterogeneity. Finally, we calculated the change of Coulomb stresses associated with 49 major (M ≥ 6.5) earthquakes in the North China block since 1303. The results show that ~80% of these events occurred in regions of increasing Coulomb stresses caused by previous events.

Sediment transported from interrill areas is generally finer than the in situ soil matrix. We hypothesized that sediment size depends on the processes dominating interrill sediment transport, i.e., splash or wash, which, in turn, are influenced by rainfall intensity and slope gradient. Aggregate size distribution of directional splash and wash sediment from a Rhodic Eutrustox (Wahiawa silty clay) was measured at 4, 9, 18, 27, and 36% slopes under simulated rainfall with 45, 65, 90, and 135 mm h−1 intensities. Mean sediment geometric mean diameter (GMD) was 0.74 mm for downslope splash, 0.67 mm for lateral splash, 0.59 mm for upslope splash, and 0.40 mm for wash. Both splash and wash preferentially transported aggregates <0.063 mm. However, mean enrichment ratios (ER) for this fraction were <2 for splash and ≈12 for wash. Wash sediment GMD significantly increased with increasing rainfall intensity and slope, and was thus positively correlated with the erosion rate of wash (r = 0.95). In contrast, splash sediment GMD was much less influenced by rainfall intensity and slope, and was weakly correlated with the corresponding splash rate (r = −0.17 for total splash). Splash tended to generate sediment with similar size to the in situ soil and the size sorting process was in a matrix‐limited regime. Wash appeared to be in a force‐limited regime and produced sediment that was much finer than the in situ soil.

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Episodic slow slip (ESS) events have been detected at several circum-Pacific subduction zones, such as Cascadia, Japan, and Mexico. Notably, at least eight ESS events along the northern Cascadia subduction zone recurred with a period of 13-16 months. We study the relationship between pole-tide (associated with Chandler wobble with a period of ϳ14 months)-induced stress and the occurrence of the ESS events. Our quantitative analysis shows that 14 of the 20 documented ESS events occurred during the ascension phase, prior to the maximum, of a pole-tide-induced Coulomb failure stress change, and three events occurred at the stress-change peak. The pole tides modulate the stress field at the downdip edge of the transition zone along the plate interface and may trigger ESS events when conditions are favorable. The phase advance of the triggered events with respect to the induced Coulomb failure stress change may reflect that the fault slip is dictated by a rate-and statedependent friction law inferred from laboratory experiments.