On February 6, 2023, two destructive earthquakes struck southern and central Turkey and northern and western Syria. The epicenter of the first event(M_W7.8)was 37km west-northwest of Gaziantep. The earthquake had a maximum Mercalli intensity of Ⅻ around the epicenter and in Antakya. It was followed by a M_W7.7 earthquake nine hours later. This earthquake was centered 95km north-northeast from the first one. There was widespread damage and tens of thousands of fatalities. In response to these catastrophic events, in March 2023, a seismic scientific expedition led by China Earthquake Administration(CEA)was promptly organized to investigate the surface ruptures caused by these earthquakes. Here, we focus on the surface ruptures of the second earthquake, known as the Elbistan earthquake. The post-earthquake field survey revealed that the Elbistan earthquake occurred on the East Anatolian fault zone's northern branch(the Cardak Fault). This event resulted in forming a main surface rupture zone approximately 140km long and a secondary fault rupture zone approximately 20km long, which is nearly perpendicular to the main rupture.

We combined the interpretation of high-resolution satellite imagery and geomorphic investigations along the fault to determine the fault geometry and kinematics of the second earthquake event. The Elbistan earthquake formed a main surface rupture zone approximately 140km long, which strikes in an east-west direction along the Cardak Fault. The main rupture zone starts from Göksun in the west and extends predominantly eastward until the western end of the Sürgü Fault. It then propagates northeast along the southern segment of the Malatya fault zone. The entire Cardak Fault and the Malatya fault zone's southern segment are considered seismic structures for this earthquake. The overall surface rupture zone exhibits a linear and continuous distribution. Secondary ruptures show a combination of left-lateral strike-slip or left-lateral oblique-thrust deformation. Along the rupture zone, a series of en echelon fractures, moletracks, horizontal fault striations, and numerous displaced piercing markers, such as mountain ridges, wheat fields, terraces, fences, roads, and wheel ruts, indicate the predominance of pure left-lateral strike-slip motion for most sections. The maximum measured horizontal displacement is(7.6±0.3)m. According to the empirical relationship between the seismic moment magnitude of strike-slip faulting earthquakes and the length of surface rupture(SRL), a main rupture zone of 140km in length corresponds to a moment magnitude of approximately 7.6. Based on the relationship between the seismic moment magnitude and the maximum coseismic displacement, a maximum coseismic displacement of(7.6±0.3)m corresponds to a moment magnitude of about 7.5. The magnitudes derived from the two empirical relationships are essentially consistent, and they also agree with the moment magnitude provided by the USGS. Besides the main surface rupture zone, a secondary fault rupture zone extends nearly north-south direction for approximately 20km long. Unfortunately, due to the limited time and traffic problem, we did not visit this north-south-trending secondary fault rupture zone.

According to the summary of the history of earthquakes, it is evident that the main surface rupture zone has only recorded one earthquake in history, the 1544 M_S6.8 earthquake, which indicates significantly less seismic activity compared to the main East Anatolian Fault. Moreover, the “earthquake doublet” will inevitably significantly impact the stress state and seismic hazard of other faults in the region. Seismic activity in this area remain at a relatively high level for years or even decades to come. The east-west striking fault, which has not been identified on the published active fault maps at the western end of the surface rupture zone, and the north-east striking Savrun Fault, which did not rupture this time, will experience destructive earthquakes in the future. It remains unknown why the east-west striking rupture did not propagate to the Sürgü Fault this time. More detailed paleoearthquake studies are needed to identify whether it is due to insufficient energy accumulation or because this section acts as a barrier. If the Sürgü Fault, about 40km long, was to rupture entirely in the future, the magnitude could reach 7 based on the empirical relationship.

Considering the distribution of historical earthquakes along the East Anatolian fault zone, as well as the geometric distribution of the surface ruptures from the recent “earthquake doublet” and the surrounding active faults, it is believed that the future earthquake hazards in the northeastern segment of the East Anatolian fault zone, the northern segment of the Dead Sea Fault, and the Malatya Fault deserve special attention.

Low-temperature thermochronology is a key technology for studying neotectonics and landscape evolution. However, it is intrinsically different from the other geochronological methods in the data expression, analysis and interpretation. In recent years, with the widespread adoption of low-temperature thermochronology techniques, the size volume of data has continuously increased, giving rise to many studies on tectonic geomorphic evolution based on big data. However, these data are mostly scattered across literature from different sources, with inconsistent formats and contents, and varying data quality, which to a certain extent hampers innovative research based on big data. There is a need to construct specialized databases to cope with the growing low-temperature thermochronology data and meet the demands of innovative research using big data.

In this paper, four conventional geochronological databases, including National Geochronological Data Base, Geochron, Petlab, DataView, and recent databases, AusGeochem and Sparrow are reviewed for comparison of their capability in data sources, data volume, data storage structure, completeness of data content, data entry methods, data retrieval methods, coverage areas, database update patterns, and data analysis tools. The conventional geochronological databases, of which the thermochronological data comprise only a small part, are generally stored in databases similar to or outside this subject, such as radioisotope chronology database, geochronology database, petrological mineral and geological analysis databases. They amplify the commonalities between different disciplines, and thus focus only on the presentation of sample units. It is not suitable for “big data” research, because all the data are managed by relational database with strictly structured tables and limited data sources. It was found that conventional geochronological databases design approaches are often suitable for absolute age data. However, low-temperature thermochronology differs from conventional geological dating methods, as its age values only record cooling time. The more geologically significant cooling history comes from numerical simulations based on elevation profiles, track lengths, and the diffusion dynamics models of the(U-Th)/He system. Additionally, the innovation in experimental techniques also imposes new requirements on the construction of thermochronology databases.

Comparing with the conventional geochronology databases, recent databases focus more on low-temperature thermochronological data and support both the structured and unstructured data with variable data sources, which makes it more comprehensive and professional. These databases own the characteristics of flexibility and expandability, especially for the addition of new dating methods and experimental methods, the storage of big data and the linkage between laboratories and database. Using different types of database platform and associated APIs, both relational and non-relational data can be involved and managed for data query, analysis and visualization. However, the construction of these recent databases is still in the preliminary exploration stage, and ensuring the continuous growth of data remains a challenge. Moreover, establishing a flexible numbering system for sustainable and expandable unique identification of samples and data is also an important task for recent databases. Finally, in addition to raw data, numerous thermal history information is included in published paper related to fission track. These interpretations or inverted results constitute interpretive data, which are crucial for reconstructing cooling history or tectonic uplift. Therefore, how to incorporate such data into the database is also a question that must be considered during database design.

The key to supporting the database lies in the users who it oriented. Considering the needs of users in professional field for scientific research management, experimental analysis and “big data” innovative research, as well as in view of the problems existing in the current databases, we put forward following suggestions for the future construction of low-temperature thermochronology database.

Firstly, in order to ensure the activity of specific low-temperature thermochronology database. from a technical perspective, artificial intelligence technologies such as natural language processing or other forms of machine learning algorithms should be utilized to semi-automatically or automatically extract information from paper, assisting users in quickly extracting relevant information and understanding the content of the literature. Platforms like Semantic Scholar, GeoDeepDive, and DeepShovel have implemented interactive features in data mining, wherein data is normalized and automated into the database based on user-specified rules, significantly reducing manpower and time costs in data acquisition, providing great convenience. In terms of ideology, the open-sharing academic ecosystem has given rise to open-sharing platforms such as arXiv for preprints, data repositories like Pangaea, and the Deep-Time Digital Earth integrated online research platforms, drastically shortening the cycle from research and experimentation to publication. This facilitates the incorporation of the latest research data into databases, greatly expanding the data sources. Regarding user volume, academic social networks possess advantages in academic tracking and dissemination, breaking down academic-related hierarchies, promoting academic exchange and cooperation, and attracting more users.

Secondly, more detailed data storage capabilities and simpler data operation behaviors help improve the expansibility of the database. Most existing geochronological databases use relational databases, which are a strictly structured way of storing data. The most typical data structure presentation form is two-dimensional table, which is very suitable for logical geological data. However, non-relational databases are not tables but databases oriented towards structured and unstructured data storage requirements, which have filled the gaps in relational databases. In practical applications, the advantages of both types of databases can be combined to comprehensively include basic geological information and interpretive information, achieving the effect of New SQL.

Thirdly, highlight its highlight. Chronological data of sample and the single data that make up the sample chronology are significant, it will be effective in distinguishing low-temperature thermochronology from other similar disciplines if the coding style of sample and single data that are not registered on IGSN can be standardized to highlight the characteristics of subject data.

Finally, by combining the strengths of both conventional and recent databases, incorporating the concept of open academia, leveraging advanced information mining and transmission technologies, and utilizing a storage approach that combines structured and unstructured data, it can greatly meet the comprehensive needs of users, ranging from laboratories to scientists, and further to data consumers.

Slip rate is an important parameter for the quantitative study of active fault and can be used to reflect the mode and intensity of fault activity. However, the selection of geomorphic surface, the acquisition of displacements, and the limitation of chronologic methods result in challenges to constrain the slip rate. A series of boreholes and geochronology studies revealed a continuous sedimentary sequence of the Quaternary in the Yuncheng Basin in the southern Shanxi Graben System. Multiple late Quaternary river terraces have developed and been preserved in the northern piedmont of the Zhongtiao Shan. The activities of the north Zhongtiao Shan Fault resulted in the elevation difference between the strata in the Yuncheng Basin and the river terraces. In this study, we chose the geomorphic units of the Xiaolicun River and combined them with the results of boreholes in the Yuncheng Basin to constrain the slip rates of the north Zhongtiao Shan Fault since the Late Pleistocene. Based on field observation and remote sensing image interpretation, we established the distribution and sedimentary characteristics of four terraces and the latest alluvial fan of the Xiaolicun River. Two main faults(F₁ and F₂)and a series of fractures or branch faults have been identified in these sedimentary strata. The high-resolution DEM of the faulted landform of the Xiaolicun River was obtained using UAV photogrammetry technology. Combined with a stratigraphic outcrop survey, the landform and sedimentary section across the fault were constructed. The abandonment ages of the terraces T₄, T₃, T₂, and T₁ have been determined as(214.3±13.9)ka, (118.5±6.4)ka, (59.6±2.4)ka, and(10.9±0.5)ka by OSL dating, respectively. The chronological results of the AMS ¹⁴C dating show that the alluvial fan north of F₂ was deposited at 35~1ka. Based on these results, this study established the relationship between the geomorphic evolution of the Xiaolicun River and the activities of the north Zhongtiao Shan Fault. Since the late Middle Pleistocene, F₁ had been active, accompanied by the abandonment of the T₄. At~120ka, the terrace T₃ was formed, F₁ was no longer active, but F₂ began to be active and raise T₃ and T₄ in the footwall. Since then, the Xiaolicun River has undergone rapid incision and formed T₂ and T₁. The continuous activities of F₂ maintained T₄-T₁ in an uplifted state and formed a series of fractures in the alluvial fan. Based on this evolutionary relationship, T₄, T₃ and their corresponding strata in the boreholes of the Yuncheng Basin were used to constrain the slip rate of the north Zhongtiao Shan Fault in this study. After determining the depth in boreholes corresponding to the abandoned ages of T₄ and T₃, subtracting the influence of the surface slope and the activities of the southern Salty Lake Fault, and considering the depth error caused by climate change, the vertical displacements of the north Zhongtiao Shan Fault since the two periods were obtained with the vertical slip rate of(0.31±0.05)mm/a and(0.34±0.04)mm/a, respectively. Our results indicate that the slip rates of the north Zhongtiao Shan Fault since the late Middle Pleistocene are greater than those since the Late Pliocene and Quaternary.

Coulomb stress change on active faults is critical for seismic hazard analysis and has been widely used at home and abroad. The Sichuan-Yunnan region is one of the most tectonically and seismically active regions in Mainland China, considering some highly-populated cities and the historical earthquake records in this region, stress evolution and seismic hazard on these active faults capture much attention.
    From the physical principal, the occurrence of earthquakes will not only cause stress drop and strain energy release on the seismogenic faults, but also transfer stress to the surrounding faults, hence alter the shear and normal stress on the surrounding faults that may delay, hasten or even trigger subsequent earthquakes. Previously, most studies focus on the coseismic Coulomb stress change according to the elastic dislocation model. However, the gradually plentiful observation data attest to the importance of postseismic viscoelastic relaxation effect during the analysis of seismic interactions, stress evolution along faults and the cumulative effect on the longer time scale of the surrounding fault zone. In this paper, in order to assess the seismic hazard in Sichuan-Yunnan region, based on the elastic dislocation theory and the stratified viscoelastic model, we employ the PSGRN/PSCMP program to calculate the cumulative Coulomb stress change on the main boundary faults and in inner blocks in this region, by combining the influence of coseismic dislocations of the M≥7.0 historical strong earthquakes since the Yongsheng M7.8 earthquake in 1515 in Sichuan-Yunnan region and M≥8.0 events in the neighboring area, and the postseismic viscoelastic relaxation effect of the lower crust and upper mantle.
    The results show that the Coulomb stress change increases significantly in the south section of the Xianshuihe Fault, the Anninghe Fault, the northern section of the Xiaojiang Fault, the southern section of the Longmen Shan Fault, the intersection of the Chuxiong-Jianshui Fault and the Xiaojiang Fault, and the Shawan section of the Litang Fault, in which the cumulative Coulomb stress change exceeds 0.1MPa. The assuming different friction coefficient has little effect on the stress change, as for the strike-slip dominated faults, the shear stress change is much larger than the normal stress change, and the shear stress change is the main factor controlling the Coulomb stress change on the fault plane. Meanwhile, we compare the Coulomb stress change in the 10km and 15km depths, and find that for most faults, the results are slightly different. Additionally, based on the existing focal mechanism solutions, we add the focal mechanism solutions of the 5 675 small-medium earthquakes(2.5≤M≤4.9)in Sichuan-Yunnan region from January 2009 to July 2019, and invert the directions of the three principal stresses and the stress shape factor in 0.1°×0.1° grid points; by combining the grid search method, we compare the inverted stress tensors with that from the actual seismic data, and further obtain the optimal stress tensors. Then, we project the stress tensors on the two inverted nodal planes separately, and select the maximum Coulomb stress change to represent the stress change at the node. The results show that the cumulative Coulomb stress change increase in the triple-junction of Sichuan-Yunnan-Tibet region is also significant, and the stress change exceeds 0.1MPa.
    Comprehensive analysis of the Coulomb stress change, seismic gaps and seismicity parameters suggest that more attention should be paid to the Anninghe Fault, the northern section of the Xiaojiang Fault, the south section of the Xianshuihe Fault, the southern section of the Longmen Shan Fault and the triple-junction of the Sichuan-Yunnan-Tibet region. These results provide a basis for future seismic hazard analysis in the Sichuan-Yunnan region.

The Huashan piedmont fault, forming a part of the southern margin of the Weihe graben, is one of the important normal faults that control the subsidence of the intracontinental rift. Developing on the footwall of the fault, the Huashan block has experienced rapid cooling during the Cenozoic, especially since the early-middle Miocene. Mountain exhumation causes and transports a great amount of sediments to the adjacent hanging wall, setting a typical case of mountain-basin coupling system. Studies on active tectonics, historical and paleo earthquakes and field investigations reveal that the middle section(Huaxian-Huayin)of the fault is much more active than the west(Lantian-Huaxian)and east(Huayin-Lingbao)sections.
    We extracted channel profiles of rivers that originate from the main water divide of the northern flank of the Huashan Mountain. Based on the method of slope-area analysis and the integral approach, we identified knickpoints, calculated channel concavity and steepness indices, and constructed paleo river profiles. Of most rivers, the concavities are within a relatively narrow range of 0.3~0.6, with no obvious correlation with tectonics. However, channel steepness and knickpoint distribution vary spatially. In the east section, rivers are under steady-state with smooth, concave-up channels and lower steepness((104±30)m^0.9). In the other two sections, rivers are mainly under transient state with slope-break knickpoints. For the channel segments below knickpoints, steepness indices are much higher in the middle section((230±92)m^0.9)than in the west((152±53)m^0.9). Thus, the variance of fault activity can be reflected by channel steepness pattern. Above the knickpoints, channel steepness indices are much lower(middle(103±23)m^0.9, west(60±14)m^0.9). What's more, we found a statistically significant power-law scaling between knickpoint retreat distance and catchment drainage area. Thus, we attributed these knickpoints to be the results of recent rapid uplift of the Huashan block. The relief of paleo channels(middle(1000±153)m, west(751±170)m)accounts for~60%~80% of the relief of modern rivers(middle(1323±249)m, west(1057±231)m), which means that ~20%~40% of modern channel relief was caused by the episode of the rapid uplift. Assuming a balance between the rates of rock uplift and downstream river incision, a power-law function between uplift rates and channel steepness can be derived. According to the fault throw rates of the middle section 1.5~3mm/a(since late Pleistocene), we constrained slope exponent n~0.5 and channel erodibility K~1.5×10^-4m^0.55/a. Combining the knickpoint age formula, we estimated that the rapid mountain uplift/fault throw began at ~(0.55±0.25)Ma BP. Therefore, the middle of the Huashan piedmont fault is more active than the west and east sections. The fast fault throw of the west and middle sections since the middle Pleistocene has caused rapid mountain uplift and high topographic relief.

Influenced by the far-field effect of India-Eurasia collision, Tianshan Mountains is one of the most intensely deformed and seismically active intracontinental orogenic belts in Cenozoic. The deformation of Tianshan is not only concentrated on its south and north margins, but also on the interior of the orogen. The deformation of the interior of Tianshan is dominated by NW-trending right-lateral strike-slip faults and ENE-trending left-lateral strike-slip faults. Compared with numerous studies on the south and north margins of Tianshan, little work has been done to quantify the slip rates of faults within the Tianshan Mountains. Therefore, it is a significant approach for geologists to understand the current tectonic deformation style of Tianshan Mountains by studying the late Quaternary deformation characteristics of large fault and fold zones extending through the interior of Tianshan. In this paper, we focus on a large near EW trending fault, the Baoertu Fault (BETF) in the interior of Tianshan, which is a large fault in the eastern Tianshan area with apparent features of deformation, and a boundary fault between the central and southern Tianshan. An M_S5.0 earthquake event occurred on BETF, which indicates that this fault is still active. In order to understand the kinematics and obtain the late Quaternary slip rate of BETF, we made a detailed research on its late Quaternary kinematic features based on remote sensing interpretation, drone photography, and field geological and geomorphologic survey, the results show that the BETF is of left-lateral strike-slip with thrust component in late Quaternary. In the northwestern Kumishi basin, BETF sinistrally offsets the late Pleistocene piedmont alluvial fans, forming fault scarps and generating sinistral displacement of gullies and geomorphic surfaces. In the bedrock region west of Benbutu village, BETF cuts through the bedrock and forms the trough valley. Besides, a series of drainages or rivers which cross the fault zone and date from late Pleistocene have been left-laterally offset systematically, resulting in a sinistral displacement ranging 0.93~4.53km. By constructing the digital elevation model (DEM) for the three sites of typical deformed morphologic units, we measured the heights of fault scarps and left-lateral displacements of different gullies forming in different times, and the result shows that BEFT is dominated by left-lateral strike-slip with thrust component. We realign the bended channels across the fault at BET01 site and obtain the largest displacement of 67m. And we propose that the abandon age of the deformed fan is about 120ka according to the features of the fan. Based on the offsets of channels at BET01 and the abandon age of deformed fan, we estimate the slip rate of 0.56mm/a since late Quaternary. The Tianshan Mountains is divided into several sub-blocks by large faults within the orogen. The deformation in the interior of Tianshan can be accommodated or absorbed by relative movement or rotation. The relative movement of the two sub-blocks surrounded by Boa Fault, Kaiduhe Fault and BETF is the dominant cause for the left-lateral movement of BETF. The left-lateral strike-slip with reverse component of BETF in late Quaternary not only accommodates the horizontal stain within eastern Tianshan but also absorbs some SN shortening of the crust.

At 3:05, September 4, 2017, an M_L4.4 earthquake occurred in Lincheng County, Xingtai City, Hebei Province, which was felt obviously by surrounding areas. Approximately 60km away from the hypocenter of Xingtai M_S7.2 earthquake in 1966, this event is the most noticeable earthquake in this area in recent years. On the one hand, people are still shocked by the 1966 Xingtai earthquake that caused huge disaster, on the other hand, Lincheng County is lack of strong earthquakes. Therefore, this quake has aroused widespread concerns by the government, society and seismologists. It is necessary to clarify whether the seismogenic structure of this event is consistent with the previous seismicity and whether it has any new implications for the seismic activity and seismic hazard in this region. Therefore, it is of great significance to study its seismogenic mechanism for understanding the earthquake activity in Xingtai region where a M_S7.2 earthquake had occurred in 1966.
In this study, the Lincheng earthquake and its aftershocks are relocated using the multi-step locating method, and the focal mechanism and focal depth are determined by the "generalized Cut and Paste"(gCAP)method. The reliability of the results is analyzed based on the data of Hebei regional seismic network. In order to better constrain the focal depth, the depth phase sPL fitting method is applied to the relocation of focal depth. The inversion and constraint results show that aftershocks are mainly distributed along NE direction and dip to SE direction as revealed by depth profiles. Focal depths of aftershocks are concentrated in the depths of 6.5~8.2km with an average of about 7km. The best double-couple solution of the mainshock is 276°, 69° and -40° for strike, dip and slip angle for nodal plane I and 23°, 53° and -153° for nodal plane Ⅱ, respectively, revealing that it is a strike-slip event with a small amount of normal-fault component. The initial rupture depth of mainshock is about 7.5km obtained by the relocation while the centroid depth is 6km derived from gCAP method which was also verified by the seismic depth phase sPL observed by several stations, indicating the earthquake is ruptured from deep to shallow. Combined with the research results on regional geological structure and the seismic sequence relocation results, it is concluded that the nodal plane Ⅱ is the seismogenic fault plane of this earthquake.
There are several active faults around the hypocenter of Lincheng earthquake sequence, however, none of the known faults on the current understanding is completely consistent with the seismogenic fault. To determine the seismogenic mechanism, the lucubrated research of the M_S7.2 Xingtai earthquake in 1966 could provide a powerful reference. The seismic tectonic characteristics of the 1966 Xingtai earthquake sequence could be summarized as follows:There are tensional fault in the shallow crust and steep dip hidden fault in the middle and lower crust, however, the two faults are not connected but separated by the shear slip surfaces which are widely distributed in the middle crust; the seismic source is located between the hidden fault in the lower crust and the extensional fault in the upper crust; the earthquake began to rupture in the deep dip fault in the mid-lower crust and then ruptured upward to the extensional fault in the shallow crust, and the two fault systems were broken successively. From the earthquake rupture revealed by the seismic sequence location, the Lincheng earthquake also has the semblable feature of rupturing from deep to shallow. However, due to the much smaller magnitude of this event than that of the 1966 earthquake, the accumulated stress was not high enough to tear the fracture of the detachment surface whose existence in Lincheng region was confirmed clearly by the results of Lincheng-Julu deep reflection seismology and reach to the shallower fault. Therefore, by the revelation of the seismogenic mechanism of the 1966 Xingtai earthquake, the seismogenic fault of Lincheng earthquake is presumed to be a concealed fault possessing a potential of both strike-slip and small normal faulting component and located below the detachment surface in Lincheng area. The tectonic significance indicated by this earthquake is that the event was a stress adjustment of the deep fault and did not lead to the rupture of the shallow fault. Therefore, this area still has potential seismic hazard to a certain extent.

Traditional method to generate Digital Elevation Model (DEM)through topographic map and topographic measurement has weak points such as low efficiency, long operating time and small range. The emergence of DEM-generation technology from high resolution satellite image provides a new method for rapid acquisition of large terrain and geomorphic data, which greatly improves the efficiency of data acquisition. This method costs lower compared with LiDAR (Light Detection and Ranging), has large coverage compared with SfM (Structure from Motion). However, there is still lack of report on whether the accuracy of DEM generated from stereo-imagery satisfies the quantitative research of active tectonics. This research is based on LPS (Leica Photogrammetry Suit)software platform, using Worldview-2 panchromatic stereo-imagery as data source, selecting Kumishi Basin in eastern Tianshan Mountains with little vegetation as study area. We generated 0.5m resolution DEM of 5-km swath along the newly discovered rupture zone at the south of Kumishi Basin, measured the height of fault scarps on different levels of alluvial fans based on the DEM, then compared with the scarp height measured by differential GPS survey in the field to analyze the accuracy of the extracted DEM. The results show that the elevation difference between the topographic profiles derived from the extracted DEM and surveyed by differential GPS ranges from -2.82 to 4.87m. The shape of the fault scarp can be finely depicted and the deviation is 0.30m after elevation correction. The accuracy of measuring the height of fault scarps can reach 0.22m, which meets the need of high-precision quantitative research of active tectonics. It provides great convenience for rapidly obtaining fine geometry, profiles morphology, vertical dislocations of fault and important reference for sites selection for trench excavation, slip rate, and samples. This method has broad prospects in the study of active tectonics.

The topography and geomorphology of active orogens result from the interaction of tectonics and climate. In most orogens, a fluvial channel is most sensitive to the coupling between tectonics, lithology, and climate. Meanwhile, the related signals have been recorded by both the drainage geometry and channel longitudinal profile. Thus, how to extract tectonic information from fluvial channels has been a focused issue in geologic and geomorphologic studies.
The well known stream-power river incision model bridges the gap between tectonic uplift, river incision and channel profile change, making it possible to retrieve rock uplift pattern from river profiles. In this model, the river incision rate depends on the rock erodibility, contributing drainage area and river gradient. The steady-state form of the river incision model predicts a power-law scaling between the drainage area and channel gradient. Via a linear regression to the log-transformed slope-area data, the slope and intercept are channel concavity and steepness indices, respectively. The concavity relates to lithology, climatic setting and incision process while the channel steepness can be used to map the spatial pattern of rock uplift. For its simple calculation process, the slope-area analysis has been widely used in the study of tectonic geomorphology during past decades.
However, to calculate river slope, the coarse channel elevation data must be smoothed, re-sampled, and differentiated without any reasonable smooth window or rigid mathematical fundamentals. One may lose important information and derive stream-power parameters with high uncertainties. In this paper, we introduce the integral approach, a procedure that has been widely used in the latest four years and demonstrated to be a better method for river profile analysis than the traditional slope-area analysis. Via the integration to the steady-state form of the stream-power river incision equation, the river longitudinal profile can be converted into a straight line of which the independent variable is the integral quantity χ with the unit of distance and the dependent variable is the relative channel elevation. We can calculate the linear correlation coefficient between elevation and χ based on a series of concavity values and find the best linear fit to be the reasonable channel concavity index. The slope of the linear fit to the χ value and elevation is simply related to the ratio of the uplift rate to the erodibility.
Without calculating channel slope, the integral approach makes up for the drawback of the slope-area analysis. Meanwhile, via the integral approach, a steady-state river profile can be expressed as a continuous function, which can provide theoretical principle for some geomorphic parameters (e.g., slope-length index, hypsometric integral). In addition, we can determine the drainage network migration direction using this method. Therefore, the integral approach can be used as a better method for tectonogeomorphic research.

Interactions of two global-scale geodynamic systems control Cenozoic tectonic evolution of continental eastern Asia: the collisional and convergent system between Indian and Eurasian plates, the subduction and back-arc extensional system along the western Pacific and Indonesian oceanic margins. The warm and broad Tethys Ocean separates the Indian plate in the south from the Eurasian plate in the north, while the former subducts beneath the latter. In the meanwhile, the Pacific plate continuously subducts westward beneath the Eurasian plate. As the rate of subduction decreases with the time, back-arc extensional basins began to form due to trench rollback along the subduction zone. Though it is still under debate on the timing of initiation of collision between India and Eurasia, the main stage or significant collision probably took place between 55 and 45Ma. The collision and subsequent penetration of India into Eurasia cause retreat of the Tethys Ocean, crustal thickening of the southern and central Tibet, uplifting of Proto-Tibetan plateau, and southeastward extrusion of crustal material of Tibetan plateau. The timing and direction of extrusion of Tibet's crustal material coincide with acceleration of trench rollback of back-arc extensional system along the western Pacific and Indonesian oceanic margins. The collision caused shortening and trench rollback induced extension appear to form a causal "source-sink relationship". In the period of 30 to 20Ma, the northeastward convergence of the Tibetan plateau increased as the southeastward extrusion slowed down that in turn caused northeastward and eastward growth of the plateau. The Main Boundary Thrust became southern collisional boundary between the Indian and Eurasian plates. The northern deformational boundary migrated to the Kunlun Fault zone, forming compressional foreland basins such as the Qaidam, Hexi Corridor, and Longxi Basins. The rapid trench rollback has decreased along the subduction and back-arc extensional system along the western Pacific and Indonesian oceanic margins. As a result, the Japan Sea has ceased extension and the North China Plain Basin has changed from rifting to thermal subsidence. The east-west direction extension initiates in the interior of Tibetan plateau since approximate 10Ma ago, forming a series of north-trending grabens and half-grabens in the high altitudes above 5 000m. In the same time, the Tibetan plateau grows outward so that the Qilian Shan uplifted to form a major mountain range along the northern boundary and the Longmen Shan uplifted again to form an about 4000 relief with respect to Sichuan Basin. Along the eastern coast of Eastern Asia, subduction of Pacific plate beneath the Eurasian plate has accelerated to terminate back-arc extension.

Tectonic geomorphology introduces the quantitative topographic factors to describe and characterize the landform in real world, which is accepted as one efficient approach in neotectonics study now. More and more qualitative and quantitative researches have been implemented to delve into the response of surface topography to tectonic activity, or discuss the further subsequent geomorphology evolution. The various topographic characteristics along the middle-east segment of the Haiyuan Fault, which is located on the northeastern margin of Tibet plateau, indicate the different geotectonic backgrounds and evolution processes. Five quantitative topographic factors (i.e. elevation, slope, local relief, residual relief and channel steepness)derived from 90-m-grid SRTM DEMs all demonstrate higher values on the western section, lower values on the eastern section and middle section as well. However, all factors slightly increase to local peak values at the southeastern tailing end. Combining with average annual precipitation and geologic mapping, we discuss the basic mechanism about how geotectonic, climate and bedrock type would impose and build up various landforms. As demonstrated by our analysis our analysis, the precipitation is thought to aggravate the surface erosion and accelerate the landform evolution, and there is no significant correlation between the distribution of topographic factors and the bedrock type. Statistic result indicates the relative strong extrusion uplift on the western section. The middle part is a transitional zone and affected by Yellow River incision and widespread fluvial terraces. The influence of compressive folding at the southeastern tail of large strike-slip fault is also revealed by topographic variations.

Because of lack of Quaternary volcano activity in China,Quaternary sediments become the main dating material in the study of geological structure, topographic feature and environment evolution,etc.ESR is a potential dating method for the sediments older than 200ka.After sunlight bleaching or heating,the quartz ESR signals,including E'-,Ge-,Al-,Ti-center,can attenuate or be reset.The sediments deposited during Quaternary period only have the effect of sunlight bleaching before the last burial time.Therefore,the sunlight bleaching characteristics of ESR signal centers is one of the most important factors in ESR dating.In this study,the paper firstly makes a simple introduction on the ESR theoretical basis and the measuring process of dose rate(D) and equivalent dose(ED),and then,reviews the sunlight bleaching characteristics and the applications in Quaternary geochronology of different ESR signal centers.The E'-center ESR signal increases with the sunlight bleaching during first 72 hours,it is not suitable for the sediment dating.Ge-center ESR signal is bleachable and can be reset after several hours sunlight bleaching,so,it is the most light sensitive signal center.However,it is very difficult to measure the Ge-center ESR signal in laboratory because it is very weak.Al-center can attenuate 20 percent after 2 hours sunlight bleaching and after tens to hundreds of hours bleaching it still maintains a stable residual signal,50-80 percent.The remnant signals are not equal under different sediment environment.We usually gain a bigger age using Al-center ESR signal for the uncertain remnant.Ti-center ESR signals can be totally bleached after tens to hundreds of hours sunlight bleaching,and this ESR signal also has enough intensity for measurements.According to the review of all the ESR signal centers' sunlight bleaching characteristics and several successful application examples,we suggest that Ti-center ESR signal is more suitable than others for the ESR dating of Quaternary sediment.

Terrestrial in situ cosmogenic nuclides burial dating has a promising application in dating of late Cenozoic detrital sediments,for example,cave sediments,fluvial sediments and moraine.This method relies on a pair of cosmic-ray-produced nuclides that are produced in the same rock or mineral target at a fixed ratio,but have different half-lives.For example, ²⁶ Al and ¹⁰ Be are produced in quartz at ²⁶ Al :¹⁰ Be=6.75 :1.The ratio is not affected by latitude and altitude.After sediments are buried,the ratio would become less as time goes.Therefore, ²⁶ Al/¹⁰ Be ratio can be used as a geological clock.The dating range can be from several hundreds of thousand years to five million years.In this article,we introduce four methods and their applications: exposure-burial diagram method,depth profile method,isochron method, ²⁶ Al-²¹ Ne and ¹⁰ Be-²¹ Ne method.Exposure-burial diagram method is often applied to cave sediments dating, for exposure-burial history of cave deposits is easy.Depth profile method is applied to fluvial sediments dating.There is a good application for isochron approach in till-paleosol sequences in North America. ²⁶ Al-²¹ Ne and ¹⁰ Be-²¹ Ne method has a great potential applicaton in future for its larger dating time and less uncertainty than other methods.The dating method still has many problems.Firstly,there are no exact half-lives.For example,there is still controversy for ¹⁰ Be half-life.Its estimate is 1.51±0.06Ma or 1.36±0.07Ma.Secondly,it is also a debate how to determine nuclides' production rates.In addition,post-burial or preburial erosion rate,inheritance nuclides concentration,post-burial nuclide production,effect of post-burial or preburial muonic production,sediment rework,complicated exposure-burial history of sediments all bring great challenges to cosmogenic nuclides dating.

Based on careful selection of underground fluid observation wells(springs),and using the monthly means and subordinate function method,we select the precursory anomalies information of underground water level before the moderately strong earthquakes in Hainan and its vicinity from these wells(springs)and analyze the characteristics of these precursory anomalies.Anomalies in water level are categorized into two classes: ascending medium term anomalies and descending medium-short term anomalies.Statistics show that the average time of medium-short term anomalies in subordinate function is approximately one year before the earthquake,which can be used as reference time index for mid and short term earthquake prediction in this area.

No moderate and strong earthquake occurred for many years in Wenxian since the M8.0 great earthquake occurring in 1879 A.D. The June 21,2006 Wenxian earthquake with M5.0 occurred in an area where the tectonic setting is complex. Seismic activity level in Wenxian would enhance after the occurrence of this earthquake(M5.0). Since the earthquake did not produce surface rupture zone,it is very difficulty to study the seismogenic fault. However,we can still study the seismogenic fault based on geological map(1∶200 000),remote sensing interpretation,inversion of focal mechanism and seismic sequence precise location method. In order to determine the future seismic risk of the region,the paper intends to analyze the earthquake causative structure by jointly using the remote sensing interpretation,various methods of inversion of focal mechanism,and double-difference earthquake location algorithm. The geological map(1:200 000)shows there are many faults in this area,and the interpretation of remote sensing reveals that only one fault named Shifang-Linjing Fault is active. Focal mechanisms derived from the two methods show that the earthquake is of left-lateral strike-slip and thrust,and the principal compressive stress is in the direction of N60°E. The results of double-difference earthquake locations also support this result. The distribution of aftershocks is related to the thrust faulting. Results of combined analyses show that the Shifang-Linjiang Fault is the seismogenic fault of this earthquake,and the direction of the principal compressive stress is N60°E.

Active tectonics studies focus on the active faults,active folds,active basins and the crustal and lithosphere blocks confined by the above-mentioned active structures.Tectonic deformation style,magnitude,and corresponding rate determined by active tectonic studies are fundamental for testing and constructing some kinematic and kinetic models.And these rates are necessary boundary conditions for testing and proposing the kinematic and kinetic models.Therefore,active tectonic rates must be quantified for better understanding and interpreting the above key models.Terrestrial in situ cosmogenic nuclides(TCNs)dating techniques have been discovered and developed for decades following the AMS emergence.And then they were widely utilized for geological issues,especially for the geomorphic processes and active tectonics.Production rates of cosmogenic nuclides can change spatially and temporally,therefore,they must be corrected before being applied and interpreted.During the field investigation,the influences such as sample depth,height,latitude and shielding features,intermittent covering and sample location shifting,should be carefully and impersonally considered because of their necessity for applying the results.Based on the samples and detailed field investigation,slip rates of the active faults,river incision rates within active domain,paleoearthquake events and active volcanic eruption events can be constrained by TCNs dating.Active fault slip rate is widely utilized for paleoearthquake research and earthquake prediction,and many classic models for plateau uplift and evolution were conceived based on distribution features and slip rates of active faults.While the river incision processes within active orogen are becoming key issues for studying tectonic and fluvial geomorphology.The incision process and its rate are one of the new insights for understanding the tectonic uplift and climatic change processes.Paleoearthquake and historical earthquake studies can provide the parameters for earthquake recurrence interval,and for consequent earthquake prediction and mitigating earthquake disasters.Besides the above active rates,the volcanic eruption events during the Quaternary can help us know the relative tectonic activities,crustal and mantle geochemistry process and landscape evolution history.After briefly introducing the basic theory of TCNs,the present paper will generalize recent results and data by TCNs dating in active tectonic studies,and then put its emphasis on the procedure and consequent interpretation for these active tectonic rates.

We have conducted an integrated survey and investigation on the Quaternary activity of the Liaocheng-Lankao buried fault. The used methods include geochemical exploration, shallow seismic exploration, drilling geological profile and neo-strata dating. The object is to determine the accurate location of the fault, dislocation amount of each time period since Quaternary and the offset age of the last time of dislocation. The results show that the dislocation of the fault extends upward to the depth 20m or so below the surface. This fault has been active in early Holocene time. The average slip rate of the fault is 0.12mm/a.

In this paper, a new method, general reciprocal method(GRM), is used in interpretation of P_g wave data along HQ-13 line in Jiangsu Province. By the GRM method, wave data are firstly processed on microcomputer and then interpreted. The procedure is more fast and more effective than traditional method. The result of processing of drill data comfirms that the GRM solution is more accurate than that of T_oT_p method.

The virtual geomagnetic poles (V. G. P) in Late Paleozoic for the Junggar block are not distinct obviously from those of the Tarim and the Kazakhstan blocks but the observed paleolatitudes close to the expected values calculated from paleopoles of Kazakhstan block. Therefore the Junggar and the Kazakhstan blocks were a coherent geotec-tonic unit in the Late Paleozoic. The paleomagenetic data show that the Junggar ocean in the Devonian was closed in late Carboniferous at Urlunqur River area. The tectonic evolution of Tarim and Kazakhstan blocks underwent an almost the same course as that of Siberian platform which is representative of eastern Laurasia. Siberian platform has moved northwestward from lower to higher latitudes from Late Paleozoic to early Meso-zoic and migrated southeastward since Jurassic.