To establish an experimental, practical and open scientific experimental platform for earthquake monitoring and prediction, with reference to that of the southern California earthquake center(SCEC), China Earthquake Administration initiated a project for an experimental field in Sichuan and Yunnan Province in 2014. The chosen area is a seismically active region in the southeastern margin of the Tibetan plateau. A series of work compiling basic maps have been launched to collect fundamental data of this area including geologic structure, earthquake geology, geophysics, geodesy, and geochemistry. The map of earthquake surface ruptures in this region is one of these basic maps. This paper presents the compilation of this map. It includes earthquake epicenters, earthquake surface ruptures, faults, strata, magmatic rocks, and geographical data. This work summarized 87 destructive earthquakes, and 22 earthquake surface rupture zones, and analyzed the distribution characterization of earthquake epicenters, strata and magmatic rocks. The content in the map is reliable and integrated. This work will provide reliable earthquake-geology data for establishing geodynamics models and other future research of the national experimental field of earthquake monitoring and prediction in Sichuan and Yunnan Province.

The NE-trending Xinyi-Lianjiang fault zone is a tectonic belt, located in the interior of the Yunkai uplift in the west of Guangdong Province, clamping the Lianjiang synclinorium and consisting of the eastern branch and the western branch. The southwestern segment of the eastern branch of Xinyi-Lianjiang fault zone, about 34km long, extends from the north of Guanqiao, through Lianjiang, to the north of Hengshan. However, it is still unclear about whether the segment extends to Jiuzhoujiang alluvial plain or not, which is in the southwest of Hengshan. If it does, what is about its fault activity? According to ‘Catalogue of the Modern Earthquakes of China’, two moderately strong earthquakes with magnitude 6.0 and 6.5 struck the Lianjiang region in 1605 AD. So it is necessary to acquire the knowledge about the activity of the segment fault, which is probably the corresponding seismogenic structure of the two destructive earthquakes. And the study on the fault activity of the segment can boost the research on seismotectonics of moderately strong earthquakes in Southeast China. In order to obtain the understanding of the existence of the buried fault of the southwestern segment, shallow seismic exploration profiles and composite borehole sections have been conducted. The results indicate its existence. Two shallow seismic exploration profiles show that buried depth of the upper breakpoints and vertical throw of the buried fault are 60m and 4~7m(L5-1 and L5-2 segment, the Hengshan section), 85m and 5~8m(L5-3 segment), 73m and 3~5m(Tiantouzai section), respectively and all of them suggest the buried fault has offset the base of the Quaternary strata. Two composite borehole sections reveal that the depth of the upper breakpoints and vertical throws of the buried segment are about 66m and 7.5m(Hengshan section) and 75m and 5m(Tiantouzai section), respectively. The drilling geological section in Hengshan reveals that the width of the fault could be up to 27m. Chronology data of Quaternary strata in the two drilling sections, obtained by means of electron spin resonance(ESR), suggest that the latest activity age of the buried fault of the southwestern segment is from late of early Pleistocene(Tiantouzai section) to early stage of middle Pleistocene(Hengshan section). Slip rates, obtained by Hengshan section and Tiantouzai section, are 0.1mm/a and 0.013mm/a, respectively. As shown by the fault profile located in a bedrock exposed region in Shajing, there are at least two stages of fault gouge and near-horizontal striation on the fault surface, indicating that the latest activity of the southwestern segment is characterized by strike-slip movement. Chronology data suggest that the age of the gouge formed in the later stage is(348±49) ka.

China Earthquake Urban Active Fault Surveying Project is a national important scientific and engineering project in recent years.Its map achievement,which includes 1:250,000 regional seismotectonic map and 1:50,000active fault distribution map of twenty cities,is an important integrated document and will be utilized in seismological and geologic research,protecting against earthquake,and relief of disaster.However,these maps are not drawn in uniform standards.As a result,there is lack of normalization in stratigraphic division,map information expression and map layout.The lack of standardization will lead to further problems when publishing and utilizing these documents because of the diverse information expression.This paper discusses the design philosophy,data scheme and expression,cartographic generalization,illustration standard and mapping procedure of the 1:250,000 regional seismotectonic maps and 1:50,000 urban active fault distribution maps.The map information is from urban active fault databases,which are based on ArcGIS Geodatabase technique,and the mapping procedure is based on ArcGIS mapping template technique.Therefore,the paper also introduces the mapping procedure in ArcGIS software and references the information organization in urban active fault database.Since cooperation among industries,universities and geological research institutions becomes increasingly prominent,the mapping achievement of active fault surveying is in urge of standardization and normalization.The work in this paper is based on years of work of active fault survey project.We have collected suggestions and advices from first-line technological staff to scientific experts,and then revised our work in many details.It is expected that this work can promote the standardization and normalization of the active fault map achievements.

The kinematic property of the Wenchan earthquake's surface rupture changes from strike-slip with slightly smaller dip-slip component to the dominant dextral strike-slip at the northeasternmost region between Shikan in Pingwu county and Woqian in Qingchuan county,where,the dip-slip component is reverse between Shikan and Pingxi,normal at Kuangpingzi and its north,with no compressive deformation observed,and it turns to dextral strike-slip near Woqian.The width of the surface deformation zone is less than 10m on this segment.At Dongjia,a village north of Woqian in Qingchuan,the seismic surface rupture zone mainly exhibits as extensional fissures and graben-like negative landform,which are the products of accommodation of the heterogeneous stress and strain at the tip portion of the seismic surface rupture.The width of the surface deformation zone is about 10～12m.No surface rupture evidence was found at Donghekou village in Qingchuan county,so we infer that the surface rupture zone didn't spread through the Qingshui River flowing along the three villages of Donghekou,Guanzhuang and Liangshuijing in Qingchuan county and the structural geomorphology reflects variant vertical motion.Evidence for dextral strike-slip motion was hardly found.The whole length of the rupture zone on the central fault is around 240km.In the course of the Wenchuan earthquake,the tectonic deformation on the surface along the central fault was adjusted within the range of the central fault,and didn't transfer to the external regions.

Primary evidence of the latest tectonic deformation style and the activity age of the Dayi Fault in the Sichuan Basin are obtained by field geological mapping,and surveying with the help of 3D scanner and total station.In the region of Wenshangou-Longfengchang,northeast of Dayi county on the northwestern wall of the fault,the time of Cretaceous and Neogene strata's gentle folding was measured to be between late Neogene and early Pleistocene.And obviously its forming time is later than the Longmen Shan Fault which controls the northwest boundary of Sichuan Basin's Mesozoic strata and shows a thrust-nappe structure.With the help of oil prospecting data,fault plane inclines to northwest,dip angle changes from 10°～20° in the deep to 70° at near-surface,and depth of the upper faulted point is about 200～300m.Geological and geomorphologic evidence shows that Holocene is its latest active time.The latest tectonic deformation on the Dayi Fault is represented by Holocene fold.Topographically,the deformation appears as continuous piedmont hillocks with traceable length of 2.5km,distributed en echelon in the piedmont of the Longmen Mountains and with the plane shape of single hillock being ellipse.Accordingly the Dayi Fault is inferred as a Holocene active blind fault on the basis of hillocks' section shape.

The geodatabase of scientific investigation of Wenchuan earthquake stores many field investigation data,such as the data of field geological survey sites,the surface rupture belts,the Quaternary faults in the earthquake region,paleoseismological trenches,folds,etc.Moreover,it includes some collection data,such as strata data,the catalog of the Wenchuan mainshock and aftershocks,the relocation catalog of aftershocks of the Wenchuan earthquake,the catalog of historical strong earthquake.The field data are recorded,edited,analysed,mapped and output with ArcGis,a powerful function in Gis software.The geodatabase of scientific investigation of M_S8.0 Wenchuan earthquake was initially established,which includes the basic seismological information and realizes the integrated management of spatial location and attribute information.Data can be queried,analyzed and processed for the need of the correlation analysis of the data.Seismic tectonic map and surface rupture map can be drawn with the geodatabase,which can provide the basis for the determination of safety distance from the risky seismic rupture zones in post-disaster reconstruction and for the construction of the Wenchuan earthquake geographic information system.

The Wenchuan earthquake(M_S=8.0)of May 12,2008 in Sichuan Province,China produced surface ruptures along the seismogenic reverse faults.It is very important to analyze the co-seismic surface ruptures quantitatively for the comprehension of tectonic behavior of the great earthquake.We discuss several issues about the quantitative analysis of co-seismic surface ruptures produced by reverse faults with some examples from Wenchuan earthquake.With the geometric relations between the parameters of deformation and survey data from planar and linear geomorphologic benchmark,solution methods for those parameters are provided.The vertical slip,horizontal dip-slip and dip angles on survey profiles were measured to calculate the actual deformation of the fault.The relationship between the apparent deformation and the real value was provided quantitatively for oblique profiles and linear benchmarks.We also made some discussions on the application of the survey data to the analysis of regional structural geometry and kinematics.

Field investigations show that the M_S8.0 Wenchuan earthquake of 12^th May 2008 ruptured two NW-dipping imbricate reverse faults along the Longmenshan Fault zone at the eastern margin of the Tibetan Plateau.This earthquake generated a 240km long surface rupture along the Beichuan-Yingxiu Fault characterized by right-lateral oblique faulting and a 90km long surface rupture along the Guanxian-Jiangyou Fault characterized by dip-slip reverse faulting.Maximum vertical and horizontal dispacements of 6.2m and 4.9m,respectively,were observed along the Beichuan-Yingxiu Fault,whereas a maximum vertical displacement of 3.5m occurred along the Guanxian-jiangyou Fault.This co-seismic surface rupture pattern,involving multiple structures,is among the most complicated of recent great earthquakes.Its surface rupture length is the longest among the co-seismic surface rupture zones for reverse faulting events ever reported.Aftershocks recorded by local network clearly outline the hanging wall of the Beichuan-Yingxiu Fault and indicate that the fault dips about 47? to the west.Industry seismic lines,in addition to surface ruptures and aftershocks,allow us to build a 3D model for the rupture geometry that shows crustal shortening is the dominant process along the Longmen Shan to accommodate long-term deformation.Oblique thrusting accomplished by the earthquake indicates that the east-southeastward extrusion of Tibet Plateau accommodates,in part,the continuing penetration of the Indian plate into the Eurasian plate,and this extrusion is transformed at the eastern margin of the Tibetan Plateau into crustal thickening and shortening along the Longmenshan Fault zone that is responsible for the growth of high topography in the region.