Automated machine learning for rainfall-induced landslide hazard mapping in Luhe County of Guangdong Province,China

Landslide hazard mapping is essential for regional landslide hazard management.The main objective of this study is to construct a rainfall-induced landslide hazard map of Luhe County,China based on an automated machine learning framework(AutoGluon).A total of 2241 landslides were identified from satellite images before and after the rainfall event,and 10 impact factors including elevation,slope,aspect,normalized difference vegetation index(NDVI),topographic wetness index(TWI),lithology,land cover,distance to roads,distance to rivers,and rainfall were selected as indicators.The WeightedEnsemble model,which is an ensemble of 13 basic machine learning models weighted together,was used to output the landslide hazard assessment results.The results indicate that landslides mainly occurred in the central part of the study area,especially in Hetian and Shanghu.Totally 102.44 s were spent to train all the models,and the ensemble model WeightedEnsemble has an Area Under the Curve(AUC)value of92.36%in the test set.In addition,14.95%of the study area was determined to be at very high hazard,with a landslide density of 12.02 per square kilometer.This study serves as a significant reference for the prevention and mitigation of geological hazards and land use planning in Luhe County.

Preliminary geological interpretation of long-wavelength magnetic anomalies over China and surrounding regions

Long-wavelength(>500 km)magnetic anomalies originating in the lithosphere were first found in satellite magnetic surveys.Compared to the striking magnetic anomalies around the world,the long-wavelength magnetic anomalies in China and surrounding regions are relatively weak.Specialized research on each of these anomalies has been quite inadequate;their geological origins remain unclear,in particular their connection to tectonic activity in the Chinese and surrounding regions.We focus on six magnetic high anomalies over the(1)Tarim Basin,(2)Sichuan Basin(3)Great Xing’an Range,(4)Barmer Basin,(5)Central Myanmar Basin,and(6)Sunda and Banda Arcs,and a striking magnetic low anomaly along the southern part of the Himalayan-Tibetan Plateau.We have analyzed their geological origins by reviewing related research and by detailed comparison with geological results.The tectonic backgrounds for these anomalies belong to two cases:either ancient basin basement,or subduction-collision zone.However,the geological origins of large-scale regional magnetic anomalies are always subject to dispute,mainly because of limited surface exposure of sources,later tectonic destruction,and superposition of multi-phase events.

Identification and distribution of 13003 landslides in the northwest margin of Qinghai-Tibet Plateau based on human-computer interaction remote sensing interpretation

The periphery of the Qinghai-Tibet Plateau is renowned for its susceptibility to landslides.However,the northwestern margin of this region,characterised by limited human activities and challenging transportation,remains insufficiently explored concerning landslide occurrence and dispersion.With the planning and construction of the Xinjiang-Tibet Railway,a comprehensive investigation into disastrous landslides in this area is essential for effective disaster preparedness and mitigation strategies.By using the human-computer interaction interpretation approach,the authors established a landslide database encompassing 13003 landslides,collectively spanning an area of 3351.24 km^(2)(36°N-40°N,73°E-78°E).The database incorporates diverse topographical and environmental parameters,including regional elevation,slope angle,slope aspect,distance to faults,distance to roads,distance to rivers,annual precipitation,and stratum.The statistical characteristics of number and area of landslides,landslide number density(LND),and landslide area percentage(LAP)are analyzed.The authors found that a predominant concentration of landslide origins within high slope angle regions,with the highest incidence observed in intervals characterised by average slopes of 20°to 30°,maximum slope angle above 80°,along with orientations towards the north(N),northeast(NE),and southwest(SW).Additionally,elevations above 4.5 km,distance to rivers below 1 km,rainfall between 20-30 mm and 30-40 mm emerge as particularly susceptible to landslide development.The study area’s geological composition primarily comprises Mesozoic and Upper Paleozoic outcrops.Both fault and human engineering activities have different degrees of influence on landslide development.Furthermore,the significance of the landslide database,the relationship between landslide distribution and environmental factors,and the geometric and morphological characteristics of landslides are discussed.The landslide H/L ratios in the study area are mainly concentrated between 0.4 and 0.64.It means the landslides mobility in the region is relatively low,and the authors speculate that landslides in this region more possibly triggered by earthquakes or located in meizoseismal area.

An open-accessed inventory of landslides triggered by the M_(S)6.8 Luding earthquake,China on September 5,2022

This study constructs a preliminary inventory of landslides triggered by the M_(S) 6.8 Luding earthquake based on field investigation and human-computer interaction visual interpretation on optical satellite images.The results show that this earthquake triggered at least 5007 landslides,with a total landslide area of 17.36 km^(2),of which the smallest landslide area is 65 m^(2)and the largest landslide area reaches 120747 m^(2),with an average landslide area of about 3500 m^(2).The obtained landslides are concentrated in the IX intensity zone and the northeast side of the seismogenic fault,and the area density and point density of landslides are 13.8%,and 35.73 km^(-2) peaks with 2 km as the search radius.It should be noted that the number of landslides obtained in this paper will be lower than the actual situation because some areas are covered by clouds and there are no available post-earthquake remote sensing images.Based on the available post-earthquake remote sensing images,the number of landslides triggered by this earthquake is roughly estimated to be up to 10000.This study can be used to support further research on the distribution pattern and risk evaluation of the coseismic landslides in the region,and the prevention and control of landslide hazards in the seismic area.

Application and Regulation of Legal Science and Technology on the Pilot Program of the Reform of Separation between Complicated Cases and Simple Ones in Civil Procedure in the Basic People’s Courts

Blockchain,artificial intelligence,and other technologies have been increasingly integrated with the law,and the construction of smart justice and Internet courts in various places has a prominent effect on court informatization.The Supreme People’s Court is currently carrying out the pilot reform of separation between complicated and simple cases in civil procedure,and legal technology will inevitably become a major means to enable the reform.In the field of electronic litigation,legal technology itself has become a goal of the reform.Regarding the trials of pilot basic courts,legal technology has been more deeply applied in many links such as trial activities and trial management,playing an essential role in improving judicial efficiency,and becoming an important way to solve judicial dilemmas such as“litigation explosion.”However,the history of modern society reminds us that we should be reasonably optimistic about the development of technology,especially in the field of justice.

Activity evolution of landslides and debris flows after the Wenchuan earthquake in the Qipan catchment,Southwest China

The Wenchuan earthquake that occurred on 12 May 2008 induced numerous landslides.Loose landslide materials were deposited on hillslopes,and deep channels were easily remobilized and transformed into debris flows by extreme rainstorms.Twelve years after the Wenchuan earthquake,debris flows were still active in the Qipangou Ravine in the quake-hit area.In this paper,we continuously tracked the spatiotemporal evolution of the landslides and vegetation restoration and evaluated the evolution of debris flow activity in the Qipan catchment with the aid of a GIS platform and field investigations from 2008 to 2019.We observed that the area with active landslides increased sharply immediately following the earthquake,and then decreased with time;however,the total area of landslides continued to increase from 6.93 km^(2)in 2008 to 10.55 km^(2)in 2019.The active landslides shifted towards lower angles and higher elevations after 2013.Since 2009,the vegetation coverage has been gradually increasing and approaching the coverage present before the earthquake as of 2019.The landslide activity was high and the vegetation recovery rates were rapidly rising during the first five years after the earthquake;the recovery rates then slowed over time.Therefore,we divided the evolution that occurred during the post landslide period into an active period(2008-2013),a self-adjustment period(2013-2026)and a stable period(after 2026).We then proposed a quantitative model to determine the trends of landslide activity rates and NDVI values in the catchment,which indicated that the landslide activities and postseismic vegetation restoration rates in this catchment will return to preseismic levels within approximately two decades.We also analysed the runout volumes of the debris flows after the earthquakes(Diexi and Wenchuan)and the standard deviation of the vegetation coverage and predicted that the debris flow activities will last for an additional 50 years or more.

Exploration of Waterproofness of Concrete and Alkali-Aggregate Using Hydrophobic Impregnation and Coating

Part of the tunnel spoil can not be used for concrete due to alkali aggregate reaction(AAR).Water is an indis-pensable condition for AAR,so separating the alkali-aggregate from water is of great benefit to controlling the AAR.This paper investigates the modification of concrete and aggregate by hydrophobic impregnation and organic coating and then evaluates their waterproof and me chanical properties by dynamic contact angle(DCA),ultrasonic wave velocity,scanning electron microscope(SEM),nuclear magnetic resonance(NMR),and so on.For waterproofness,hydrophobic impregnation and organic coating can both improve the waterproof-ness of concrete and aggregate.The organic coating is suitable for aggregate because it wrap aggregate well.And aggregate coated by PVA can improve the interfacial transition zone(ITZ).For mechanical properties,both mate-rials will weaken the strength of the interface.Furthermore,concrete made by aggregate with organic coating shows plastic deformation and has a good correlation with the film thickness,a plastic estimation model based on flm thickness is proposed.This paper evaluates the waterproof of concrete and aggregate and finds plastic con-crete with good aggregate waterproofness which provides a new idea for the application of alkali aggregate in see-page control facilities of water conservancy projects.

Surficial stability analysis of soil slope under seepage based on a novel failure mode

Normally,the edge effects of surficial landslides are not considered in the infinite slope method for surficial stability analysis of soil slopes.In this study,the limit stress state and discrimination equation of an infinite slope under saturated seepage flow were analyzed based on the Mohr-Coulomb strength criterion.Therefore,a novel failure mode involving three sliding zones(upper tension zone,middle shear sliding zone,and lower compression zone)was proposed.Accordingly,based on the limit equilibrium analysis,a semi-analytical framework considering the edge effect for the surficial stability of a soil slope under downslope seepage was established.Subsequently,the new failure mode was verified via a numerical finite element analysis based on the reduced strength theory with ABAQUS and some simplified methods using SLIDE software.The results obtained by the new failure mode agree well with those obtained by the numerical analysis and traditional simplified methods,and can be efficiently used to assess the surficial stability of soil slopes under rainwater seepage.Finally,an evaluation of the infinite slope method was performed using the semi-analytical method proposed in this study.The results show that the infinite slope tends to be conservative because the edge effect is neglected,particularly when the ratio of surficial slope length to depth is relatively small.

Evaluation of Key Factors for the Port Logistics Development in Countries Along the Belt and Road

The port logistics capacity of countries along the Belt and Road is of great significance to promoting Chinese overseas comprehensive supporting system. The study combines quality data with numerical data to extract the key factors affecting the port logistics development for countries along the Belt and Road. Based on grey correlation analysis and factor analysis, 17 major ports of these countries are evaluated from 11 key factors. The results show that infrastructure, transportation,and entering and leaving costs are crucial for the development of port logistics. The research provides scientific decision-making basis for the construction of an overseas comprehensive supporting system under the context of the Belt and Road Initiative.