65 km Semangko Fault is part of southern segments of Sumatran Fault Zone(SFZ)which is complex corresponds to the transition from the strike-slip regime of the SFZ to the normal faulting tectonics of the Sunda Strait.T...65 km Semangko Fault is part of southern segments of Sumatran Fault Zone(SFZ)which is complex corresponds to the transition from the strike-slip regime of the SFZ to the normal faulting tectonics of the Sunda Strait.The recent publication showed branches of Semangko Fault:West Semangko Fault(WSF)and East Semangko Fault(ESF).This study estimated geodetic slip rate and locking depth of ESF using Global Positioning System(GPS)time series data from 2007 to 2019 from all available GPS sites.GPS velocities refer to Sundaland Plate were used to estimate the fault parameters of the WSF and ESF simultaneously.Non-uniformity of velocity direction shows the complexities of Semangko Fault possibly caused by the contribution of all faults around ESF.An ESF geodetic slip rate,which is 12.5±2 mm/yr was lower than WSF,which is 16.5±2 mm/yr.It is consistent with the rigid block nature of the SFZ system as northern segment slip rates have similar value.Small slip rates are possibly leading to lower generated seismic moment than the major segment of SFZ.展开更多
Understanding the viscoelastic structure of subduction zones is essential for assessing seismic hazards and understanding subduction-zone dynamics.However,the influence of lateral variations in elastic upper-plate thi...Understanding the viscoelastic structure of subduction zones is essential for assessing seismic hazards and understanding subduction-zone dynamics.However,the influence of lateral variations in elastic upper-plate thickness(H_(c))remains poorly constrained and is often overlooked.In this study,we use two-dimensional forward viscoelastic earthquake-cycle models to fit both horizontal and vertical Global Navigation Satellite System(GNSS)observations.We identify a clear trade-off between locking depth(D)and H_(c)in both components.To resolve this ambiguity,we incorporate constraints from thermal models and tremor distributions along the Cascadia Subduction Zone.As a novel result extending beyond previous kinematic models,our results reveal a systematic northward increase in H_(c)from~20 km to~30 km.This trend correlates with increasing oceanic plate age and likely reflects variations in the subaccretion and wedge-cooling processes along the trench-parallel direction.In contrast,D remains relatively uniform at~10 km,consistent with previous findings.These results demonstrate the robustness of our approach for simultaneously constraining H_(c)and D,and they suggest it may be applied to other subduction zones.Lateral variations in H_(c)significantly affect crust deformation and should not be ignored in earthquake-cycle models.Accounting for these heterogeneities improves estimates of H_(c)and D and enhances our understanding of megathrust locking,seismic hazard potential,and the physical conditions controlling episodic tremor and slip events.展开更多
Skid resistance is an important parameter for highway designs, construction, management, maintenance and safety. The purpose of this manuscript is to propose the correlation between skid resistance, which is measured ...Skid resistance is an important parameter for highway designs, construction, management, maintenance and safety. The purpose of this manuscript is to propose the correlation between skid resistance, which is measured as skid resistance trailer, and mean profile depth （MPD） or the macro surface texture, which is measured by vehicle mounted laser, so that highway agencies can predict the skid resistance of pavement without the use of expensive and time consuming skid resistance trailer, which also causes disruption of traffic in use. In this research skid numbers and MPD from 5 new asphalt pavements and 4 old asphalt pavements were collected using a locked wheel skid trailer and a vehicle mounted laser. Using the data collected, a correlation between the skid number （SN40R） collected by locked wheel skid tester and the texture data or MPD collected by a vehicle mounted laser operating at highway speeds was developed. The proposed correlation for new pavements was positive for MPD values less than 0.75 mm to reach a peak SN40R value, then there was a negative correlation as the MPD increases until the MPD value was equal to 1.1 mm and beyond the MPD value of 1.1 mm to the maximum value of 1.4 mm, SN40R value remained almost constant. There were significant data scatter for the MPD value of 0.8 mm. To explain these results, water film thickness during the friction test was calculated and the critical MPD was defined. The effect of sealed water pool on the SN40R was discussed. The test result showed a similar trend for older asphalt pavements, but with lower SN40R values due to the polishing of pavement micro-texture by traffic. Hence, a reduction factor was proposed for older pavements based on cumulative traffic volume for the above correlation to predict the skid resistance of older pavements.展开更多
基金funded by Institut Teknologi Sumatera Smart Mandiri 2019 Research Grant Fund No.B/364/IT9.C1/PT.01.03/2019
文摘65 km Semangko Fault is part of southern segments of Sumatran Fault Zone(SFZ)which is complex corresponds to the transition from the strike-slip regime of the SFZ to the normal faulting tectonics of the Sunda Strait.The recent publication showed branches of Semangko Fault:West Semangko Fault(WSF)and East Semangko Fault(ESF).This study estimated geodetic slip rate and locking depth of ESF using Global Positioning System(GPS)time series data from 2007 to 2019 from all available GPS sites.GPS velocities refer to Sundaland Plate were used to estimate the fault parameters of the WSF and ESF simultaneously.Non-uniformity of velocity direction shows the complexities of Semangko Fault possibly caused by the contribution of all faults around ESF.An ESF geodetic slip rate,which is 12.5±2 mm/yr was lower than WSF,which is 16.5±2 mm/yr.It is consistent with the rigid block nature of the SFZ system as northern segment slip rates have similar value.Small slip rates are possibly leading to lower generated seismic moment than the major segment of SFZ.
基金supported by the National Key R&D Program of China(Grant No.2023YFF0803200)the National Natural Science Foundation of China(Grant No.42288201).
文摘Understanding the viscoelastic structure of subduction zones is essential for assessing seismic hazards and understanding subduction-zone dynamics.However,the influence of lateral variations in elastic upper-plate thickness(H_(c))remains poorly constrained and is often overlooked.In this study,we use two-dimensional forward viscoelastic earthquake-cycle models to fit both horizontal and vertical Global Navigation Satellite System(GNSS)observations.We identify a clear trade-off between locking depth(D)and H_(c)in both components.To resolve this ambiguity,we incorporate constraints from thermal models and tremor distributions along the Cascadia Subduction Zone.As a novel result extending beyond previous kinematic models,our results reveal a systematic northward increase in H_(c)from~20 km to~30 km.This trend correlates with increasing oceanic plate age and likely reflects variations in the subaccretion and wedge-cooling processes along the trench-parallel direction.In contrast,D remains relatively uniform at~10 km,consistent with previous findings.These results demonstrate the robustness of our approach for simultaneously constraining H_(c)and D,and they suggest it may be applied to other subduction zones.Lateral variations in H_(c)significantly affect crust deformation and should not be ignored in earthquake-cycle models.Accounting for these heterogeneities improves estimates of H_(c)and D and enhances our understanding of megathrust locking,seismic hazard potential,and the physical conditions controlling episodic tremor and slip events.
基金sponsored by a research contract from the New Jersey Department of Transportation (FHWA-NJ-2009020)
文摘Skid resistance is an important parameter for highway designs, construction, management, maintenance and safety. The purpose of this manuscript is to propose the correlation between skid resistance, which is measured as skid resistance trailer, and mean profile depth （MPD） or the macro surface texture, which is measured by vehicle mounted laser, so that highway agencies can predict the skid resistance of pavement without the use of expensive and time consuming skid resistance trailer, which also causes disruption of traffic in use. In this research skid numbers and MPD from 5 new asphalt pavements and 4 old asphalt pavements were collected using a locked wheel skid trailer and a vehicle mounted laser. Using the data collected, a correlation between the skid number （SN40R） collected by locked wheel skid tester and the texture data or MPD collected by a vehicle mounted laser operating at highway speeds was developed. The proposed correlation for new pavements was positive for MPD values less than 0.75 mm to reach a peak SN40R value, then there was a negative correlation as the MPD increases until the MPD value was equal to 1.1 mm and beyond the MPD value of 1.1 mm to the maximum value of 1.4 mm, SN40R value remained almost constant. There were significant data scatter for the MPD value of 0.8 mm. To explain these results, water film thickness during the friction test was calculated and the critical MPD was defined. The effect of sealed water pool on the SN40R was discussed. The test result showed a similar trend for older asphalt pavements, but with lower SN40R values due to the polishing of pavement micro-texture by traffic. Hence, a reduction factor was proposed for older pavements based on cumulative traffic volume for the above correlation to predict the skid resistance of older pavements.
