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The Yushu fault, part of the Yushu–Ganzi fault zone, is one of several E‐W‐trending left‐lateral, strike‐slip fault zones that extend across the Tibetan Plateau accommodating lateral transfer of crustal material out of the collision zone between the Indian and Eurasian plates. Discontinuous left‐lateral surface rupture occurred along WNW‐ESE‐striking, near‐vertical faults during two Mw 6.9 14 April 2010 Yushu earthquakes. Geomorphic and surface‐rupture characteristics change at the base of a red cliff separating the Guoqiong and Buqionggei segments. Excavations across these segments near the Jinsha River show: (a) more continuous deposition on the down‐dropped side; and (b) how frequently these surface‐rupture histories were linked or sequential (major to great earthquakes) versus not linked (moderate/strong to large earthquakes). Trench CUG‐2011‐1 and roadcut CUG‐2012‐1 (Guoqiong segment) were on older fan surfaces and Trench CUG‐2012‐2 (Buqionggei segment) crossed a narrow graben. On the Guoqiong segment, using OxCal v.4.4 that works with IntCal20 database for Bayesian‐ordered ages from four 14C and nine OSL ages, surface ruptures occurred during earthquakes at 2010CE, ∼200BCE, ∼2400BCE, ∼4250BCE, ∼6750BCE, ∼7400BCE and ∼10400BCE consistent with an ∼2200‐year Holocene recurrence interval. For the Buqionggei segment, Bayesian‐ordered ages from six OSL ages indicate three Holocene surface ruptures occurred at 2010CE, ∼4600BCE and ∼6750BCE. Surface ruptures on both segments (suggesting linked or sequential major to great earthquakes) only occurred two to three times at 2010CE, ∼4500BCE and/or ∼6750BCE. Thus, risk of infrequent major to great Holocene earthquakes is ∼2400–∼8800 years along the Yushu fault. Plain Language Summary: We dug trenches across the Yushu fault near Guoqingyi Rodgsongdub where surface rupture related to 2010 Yushu earthquake first crosses the Jinsha River. Left lateral slip‐slip, surface rupture diminishes from 2.1 m in wide terraces and the floodplain just west of the river to 0.2 m across the narrow youngest late Holocene terrace east of the river. Thus, the river roughly separates two different segments of the Yushu fault. To the west, seven surface ruptures occurred regularly every ∼2200 years for the last 12000 years. To the east, three irregularly spaced surface ruptures occurred over the same time. We suggest stronger earthquakes (i.e., 2010 Yushu earthquake) occur when both segments lock and rupture as Major to Great earthquakes whereas unlocked Moderate to Large earthquakes occur when only one segment ruptures. Key Points: Earthquake characteristics change across a segment boundary of the active Yushu faultWest of where the Jinsha River first crosses the Yushu fault, seven surface ruptures occurred regularly every ∼2200 years for the last ∼12000 years; east of the river's terraces, only three irregularly spaced surface ruptures occurred over the same time periodWe suggest stronger earthquakes (e.g., 2010 Yushu earthquake) occur when both segments rupture as Major to Great earthquakes whereas only Moderate to Large earthquakes occur when only one segment ruptures [ABSTRACT FROM AUTHOR]

InSAR technique can measure the surface deformation with the accuracy of centimeter-level or even millimeter and therefore has been widely used in the deformation monitoring associated with earthquakes, volcanoes, and other geologic process. However, ionospheric irregularities can lead to the wavy fringes in the low frequency SAR interferograms, which disturb the actual information of geophysical processes and thus put severe limitations on ground deformations measurements. In this paper, an application of two common methods, the range split-spectrum and azimuth offset methods are exploited to estimate the contributions of the ionosphere, with the aim to correct ionospheric effects in interferograms. Based on the theoretical analysis and experiment, a performance analysis is conducted to evaluate the efficiency of these two methods. The result indicates that both methods can mitigate the ionospheric effect in SAR interferograms and the range split-spectrum method is more precise than the other one. However, it is also found that the range split-spectrum is easily contaminated by the noise, and the achievable accuracy of the azimuth offset method is limited by the ambiguous integral constant, especially with the strong azimuth variations induced by the ionosphere disturbance. [ABSTRACT FROM AUTHOR]

In the process of exploring pre-earthquake thermal anomalies using satellite infrared data, Blackett et al. (2011) found that the previously reported anomalies before the 2001 Mw 7.7 Gujarat earthquake, in India, were related to positive biases caused by data gaps due to cloud cover and mosaicing of neighboring orbits of MODIS satellite data. They supposed that such effects could also be responsible for other cases. We noted a strip-shaped TIR anomaly on March 17th, 2010, 28 days before the Ms. 7.1 Yushu earthquake (Qin et al., 2011). Here we again investigate multi-year infrared satellite data in different bands to discriminate whether the anomaly is associated with the earthquake, or is only bias caused by the data gaps. From the water vapor images, we find lots of clouds that have TIR anomalies. However, on the cloudiness background, there is an obvious strip-shaped gap matching the tectonic faults almost perfectly. In particular, the animation loops of hourly water vapor images show that the cloud kept moving from west to east, while they never covered the strip-shaped gap. We consider that the cloud with this special spatial pattern should have implied the abnormal signals associated with the seismogenic process. Based on current physical models, the satellite IR anomalies both on TIR and water vapor bands can qualitatively be explained using synthetic mechanisms. [ABSTRACT FROM AUTHOR]

The left-lateral strike-slip Xianshuihe fault system, located in eastern Tibet, is one of the most tectonically active intracontinental fault systems in China, if not in the world, along which more than 20 M >6.5 earthquakes have occurred since A.D. 1700, including the 2010 Mw 6.9 Yushu earthquake. It is therefore essential to precisely determine its slip rate, which remains poorly constrained at all time scales, in order to evaluate regional earthquake hazard. Here, we focus on the NW segment of the Xianshuihe fault system, the Ganzi fault. We studied three sites where the active Ganzi fault cuts and left-laterally offsets moraine crests and fan edges. We constrained left-lateral offsets using light detection and ranging (LiDAR) and kinematic global positioning system (GPS) methods, and we used cosmogenic dating to determine the abandonment age of the offset surfaces. We found that the slip rate remains constant along the entire Ganzi fault (~300 km) at 6-8 mm/yr at the late Quaternary time scale, consistent with geodetic (interferometric synthetic aperture radar [InSAR] and GPS) as well as geologic slip rates (4.9-7.5 mm/yr since ca. 12.6 Ma). This implies that the Manigango segment of the Ganzi fault could potentially produce a M 7.6 earthquake in the near future. While the Xianshuihe fault system propagated from west to east, the fact that the Ganzi fault's long-term slip rate is similar to that of the Xianshuihe fault to the SE suggests that the onset of the Xianshuihe fault system at ca. 13 Ma marked a major transition in tectonic regime in SE Tibet. [ABSTRACT FROM AUTHOR]

We evaluated 2011-2015 mobile relative gravity data from the Hexi monitoring network that covers the epicenter of the 2016 Menyuan Ms6.4 earthquake, Qinghai Province, China and examined the spatiotemporal characteristics of the gravity field at the focal depth. In addition, we assessed the regional gravity field and its variation the half-year before the earthquake. We use first different interpolation algorithms to build a grid for the gravity data and then introduce potential field interpolation-cutting separation techniques and adaptive noise filtering. The results suggest that the gravity filed at the focal depth of 11.12 km separated from the total gravity field at about-400~150 × 10−8 m/s2 in the second half of 2015, which is larger than that in the same period in 2011 to 2014 (±30 × 10−8 m/s2). Moreover, at the same time, the gravity field changed fast from September 2014 to May 2015 and May 2015 to September 2015, reflecting to some extent material migration deep in the crust before the Menyuan earthquake. [ABSTRACT FROM AUTHOR]

Background: An earthquake struck Yushu in Qinghai province of China on April 14, 2010, causing 2698 deaths and 12,135 injuries.The present study aimed to assess the health status, and associated determinants, of child survivors in the epicenter of the Yushu earthquake 6 years after the event.Methods: A cross-sectional survey was performed among students from two junior schools in Yushu County. Descriptive statistics, t-tests, ANOVA, Wilcoxon rank sum tests, Kruskal-Wallis H tests and stepwise linear regression analysis were used for data analysis.Results: The mean scores onmental component summary (MCS)and physical component summary (PCS) were 42.13 (SD 7.32) and 42.04 (SD 8.07), respectively. Lower PCS in the aftermath of an earthquake was associated with being trapped/in danger, injured to self, receiving no escape training while lowerMCS in the aftermath of an earthquake was associated with a lower grade level, not living with parents, fear during the earthquake, death in the family, and not receiving psychological counseling after the earthquake.Conclusions: In conclusion, the results of the present study help to expand our knowledge regarding the health status of child survivors 6 years after the Yushu earthquake. Our study provides evidence-based suggestions for specific long-term health interventions in such vulnerable populations. [ABSTRACT FROM AUTHOR]

The VLF radio signals recorded both from the ground based VLF radio wave monitoring network and the DEMETER satellite are investigated during the 2010 Ms 7.1 Yushu earthquake. The ground-based observations show that the disturbance intensity of VLF wave’s amplitude relative to the background gets an enhancement over 22% at 11.9 kHz, 27% at 12.6 kHz and 62% at 14.9 kHz VLF radio wave along the path from Novosibirsk - TH one day before the main shock, as compared to the maximum 20% observed during non-earthquake time. The space based observations indicate that there is a decrease of the signal to noise ratio (SNR) for the power spectral density data of 14.9 kHz VLF radio signal at electric field four days before the main shock, with disturbance intensity exceeding the background by over 5% as compared to the maximum 3% observed during non-earthquake time. The geoelectric field observations in the epicenter region also show that a sharp enhancement from ∼340 to 430 mV/km simultaneously appeared at two monitors 14 days before main shock. The comparative analysis from the ground and space based observations during the earthquake and non-earthquake time provides us convincible evidence that there exits seismic anomalies from the VLF radio wave propagation before the 2010 Ms 7.1 Yushu earthquake. The possible mechanism for VLF radio signal propagation anomaly during 2010 Yushu earthquake maybe related to the change of the geoelectric field nearby the earthquake zone. [ABSTRACT FROM AUTHOR]

A sliding principal component analysis (PCA) method is proposed to detect pre-earthquake ionospheric anomalies. We analyzed the precision of this new method with different length of time window in detecting the reference background total electron content (TEC). The results showed that the most suitable window length is 27 days which is consistent with the solar rotation period. We compared the precision of this new method with the sliding inter quartile range (IQR) method and the sliding average method in detecting the background TECs, and found that the precision of sliding PCA is better than those of the traditional methods in the middle and low latitudes because the detected background TEC residual errors by the sliding PCA method are less than that by the traditional methods. We adopted a more reasonable method to calculate the background value's upper and lower bounds and then take four strong earthquakes (Qinghai earthquake, Honshu earthquake, Hotan earthquake and Nepal earthquake) as examples to prove the effectiveness of the sliding PCA method. From the detection results of the sliding PCA we found that obvious ionospheric anomalies appeared on April 1, 2010, March 8, 2011, February 2, 2014, April 11, 23, year 2015. After the further analysis of the solar-terrestrial environment and the distribution of TEC anomaly area, it can be considered that the pre-earthquake anomalies on these days before the earthquake may have a large correlation with the following earthquake. In addition, the TEC anomaly area spans largely in the longitude direction along the bound of equator anomalous zone, and the anomalous morphology has the conjugate structure. This regular can provide a valuable reference for the short-impending earthquake prediction in the future. [ABSTRACT FROM AUTHOR]

The role of trust in natural hazards risk management has not been widely examined yet. In this paper, the correlation between trust in government and individuals' risk perception, as well as the perceived preparedness for earthquakes is examined. Survey data from 501 households in a Tibetan area in China affected by the 2010 Yushu earthquake are analyzed. The dependent variables are perceived seismic risk probability and consequences, as well as reported household preparedness for future earthquakes. The main predictor variable is trust in government, while trust in family members, trust in most of people in the society, trust in friends/relatives/colleagues, disaster impact, social support, socioeconomic and demographic variables (income, estimated house value, owned land, number of kids, gender, age, ethnicity, education, job categories, marriage status, political affiliation, religion, rural/urban residence) are used as control variables. Ordinal logistic regression models are employed in the analysis. The results indicate that people with higher degrees of trust in government perceive lower consequences of potential earthquakes and tend to prepare less. In the preparedness model, both perceived probability and consequences are additional strong and significant predictors. Potential theoretical and practical implications of these results are discussed. [ABSTRACT FROM AUTHOR]

Purpose The purpose of this paper is to examine the impact of media attention on corporate disaster relief.Design/methodology/approach The authors used a matched sample research design, which is considered more appropriate than a random sample design for studying events that have low-occurrence rates in general. For each donor firm in the Yushu earthquake, the authors matched the firm with a non-donor firm in the same industry and with a firm size of within ±30 percent of the total assets in the year prior to the year of the occurrence of the Yushu earthquake. Then, using the Baidu engine, which is the most popular Chinese search engine, the authors captured the online media attention to the donor firms and their disaster relief.Findings The authors found that media attention drove corporate disaster relief.Research limitations/implications Although the authors highlighted the role of the media as an important stakeholder in influencing corporate disaster relief, the authors did not fully explore the media’s influence. Future research should delve more deeply into the impact of the tenor of media coverage on corporate disaster relief.Originality/value This study reveals that the media, a particularly powerful stakeholder, can be a corporate disaster relief driver in China. [ABSTRACT FROM AUTHOR]

Using SAR interferometry on C band Envisat descending track and L band ALOS ascending track SAR images, respectively, we firstly obtain two coseismic deformation fields and one postseismic deformation of the 2010 Yushu earthquake, Tibet, China. In the meanwhile, we also obtain the azimuthal coseismic deformation of the Yushu event by Multi Aperture Interferometry (MAI) technique. With the 3 components of one-dimensional coseismic InSAR measurements, we resolve the complete 3-dimensional deformation of the 2010 Yushu event, which shows conformity and complexity to left lateral slip mechanism. The horizontal deformation is basically consistent with a sinistral slip event; whereas the vertical displacement does show certain level of complexity, which we argue is indicative of local fault geometry variation. Based on the InSAR data and elastic dislocation assumption, we invert for coseismic fault slip and early after-slip of the Yushu event. Our inversion results show major coseismic left lateral strike slip with only minor thrust component. The after-slip model fills most of the slip gaps left by the coseismic fault slip and finds a complementary slip distribution to the coseismic fault slip, which is a good indicator that future earthquake potential on the Yushu segment has been significantly reduced. [ABSTRACT FROM AUTHOR]

After an earthquake, rapidly and accurately obtaining building damage information can help to effectively guide the implementation of the emergency rescue and can reduce disaster losses and casualties. Using a single post-earthquake fully-polarimetric synthetic aperture radar (PolSAR) image to interpret building damage information not only involves a guaranteed data source but is also easy and can be rapidly implemented. This paper is focused on rapid building earthquake damage detection in urban areas using post-earthquake PolSAR data. In PolSAR images, the undamaged buildings parallel to satellite flight pass are different from the collapsed buildings, but the undamaged buildings divergent to satellite flight pass are very similar to collapsed buildings because of their volume scattering characteristics. In this paper, the method of polarization orientation angle (POA) compensation is employed to increase the scattering power of buildings divergent to satellite flight pass, and then Wishart supervised classification is implemented on the PolSAR data after POA compensation. In addition, the two parameters of normalized difference of the dihedral component (NDDC) and pHHHV are proposed to improve the classification accuracy of theWishart supervised classification, and both the undamaged buildings and collapsed buildings are determined. The study was carried out after the "4.14" Yushu earthquake in Yushu County, Qinghai province, China. The three damage levels are set for the urban area at the city block scale according to the values of the BBCR building damage index. The experimental results confirm that the scheme proposed in this paper can greatly improve the accuracy of the extraction of building damage information. [ABSTRACT FROM AUTHOR]

Background: After the earthquake on 14, April 2010 at Yushu in China, a plague epidemic hosted by Himalayan marmot (Marmota himalayana) became a major public health concern during the reconstruction period. A rapid assessment of the distribution of Himalayan marmot in the area was urgent. The aims of this study were to analyze the relationship between environmental factors and the distribution of burrow systems of the marmot and to predict the distribution of marmots.Methods: Two types of marmot burrows (hibernation and temporary) in Yushu County were investigated from June to September in 2011. The location of every burrow was recorded with a global positioning system receiver. An ecological niche model was used to determine the relationship between the burrow occurrence data and environmental variables, such as land surface temperature (LST) in winter and summer, normalized difference vegetation index (NDVI) in winter and summer, elevation, and soil type. The predictive accuracies of the models were assessed by the area under the curve of the receiving operator curve.Results: The models for hibernation and temporary burrows both performed well. The contribution orders of the variables were LST in winter and soil type, NDVI in winter and elevation for the hibernation burrow model, and LST in summer, NDVI in summer, soil type and elevation in the temporary burrow model. There were non-linear relationships between the probability of burrow presence and LST, NDVI and elevation. LST of 14 and 23 °C, NDVI of 0.22 and 0.60, and 4100 m were inflection points. A substantially higher probability of burrow presence was observed in swamp soil and dark felty soil than in other soil types. The potential area for hibernation burrows was 5696 km(2) (37.7% of Yushu County), and the area for temporary burrows was 7711 km(2) (51.0% of Yushu County).Conclusions: The results suggested that marmots preferred warm areas with relatively low altitudes and good vegetation conditions in Yushu County. Based on these results, the present research is useful in understanding the niche selection and distribution pattern of marmots in this region. [ABSTRACT FROM AUTHOR]

On April 14, 2010, a devastating Ms 7.1 earthquake occurred in Yushu, China. In the most severely struck area of Jiegu Town, approximately 94 % of the structures were damaged. A seismic intensity map was obtained based on field investigation data of structural damage in 63 residential areas, and the differences in structural damage in four intensity regions were quantitatively compared using a seismic capacity index and a damage index. The typical damage for five types of structures in the epicentral area of Jiegu Town was described and summarized in detail. Some recommendations for improving seismic capacity of buildings are provided; they include avoiding mountainous topography, non-uniform materials, and irregular layouts, as well as considering an appropriate arrangement of structural columns and belt courses for hollow concrete block and brick masonry structures. This paper provides valuable information for structural seismic design, post-earthquake reconstruction, and related work. [ABSTRACT FROM AUTHOR]

Fault zone head waves (FZHWs) travel along the bimaterial fault interface and can be used to provide high-resolution imaging of fault zone properties. Here we use aftershock data following the 2010/04/13 Mw6.9 Yushu earthquake to quantify velocity contrast along the Garzê–Yushu Fault (GYF). FZHWs are identified as low-amplitude, long-period seismic signals with polarities opposite to the direct P arrivals. We observe FZHWs at 4 stations near faults that bound both sides of the Jielong basin, which is a pull-apart basin that is partially filled by Longbao Lake. The time delays between the direct P and FZHWs increase systematically with along-strike distances, and the corresponding observed velocity contrast is on the order of 5–8%. However, we do not observe a clear increase of time delay with hypocentral depth, suggesting that the pull-apart basin forms a thick low-velocity zone that likely exists in the top few kilometers of the crust. The velocity contrast southeast of the mainshock epicenter is very small (1–3%), consistent with both field observations and seismic tomographic results. [ABSTRACT FROM AUTHOR]

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The April 14, 2010 Yushu, China, earthquake (Mw 6.9) triggered a great number of landslides. At least 2,036 co-seismic landslides, with a total coverage area of 1.194 km, were delineated by visual interpretation of aerial photographs and satellite images taken following the earthquake, and verified by field inspection. Based on the mapping results, a statistical analysis of the spatial distribution of these landslides is performed using the landslide area percentage (LAP), defined as the percentage of the area affected by the landslides, and landslide number density (LND), defined as the number of landslides per square kilometer. The purpose is to clarify how the landslides correlate the control factors, which are the elevation, slope angle, slope aspect, slope position, distance from drainages, lithology, distance from the surface rupture, and peak ground acceleration (PGA). The results show that both LAP and LND have strongly positive correlations with slope angle and negative correlations with distance from the surface rupture and distance from drainages. The highest LAP and LPD values are in places of elevations from 3,800 to 4,000 m. The slopes producing landslides are mostly facing toward NE, E, and SE. The geological units of Q al- pl, N, and T kn have the highest concentrations of co-seismic landslides. No apparent correlations are present between LAP and LND values and PGA. On both sides of the surface rupture, the landslide distributions are almost similar except a few exceptions, likely associated with the nature of the strike-slip seismogenic fault for this event. The bivariate statistical analysis shows that, in descending order, the earthquake-triggered landslide impact factors are distance from surface rupture > slope angle > distance from drainages > lithology > PGA. Besides, as the detailed co-seismic landslides inventories related to strike-slip earthquakes are still few compared with that of thrusting-fault earthquakes, this case study would shed new light on the subject. For instance, the landslide spatial distribution on both sides of the strike-slip seismogenic fault is rather different from that of thrusting-fault earthquakes. It reminds us to take different strategies of measures for prevention and mitigation of landslides induced by earthquakes with different mechanisms. [ABSTRACT FROM AUTHOR]

The Garzê-Yushu Fault is a large left-lateral shear zone in the margin of the Tibetan Plateau. It is part of the slip fault system through which the upper crust material on the margin of the Tibetan Plateau moves eastward. At Xiala Village, Luoxu Town, Shiqu County, Sichuan Province, the Garzê-Yushu Fault cuts through the front edge of the alluvial fan, resulting in fault scarps with heights of 0.2–3.7 m. Some fissures and pressure ridges caused by the Dengke AD 1896 earthquake can be found here. The main tributary river and some gullies on the alluvial fan were also left-laterally displaced. Based on active tectonic geomorphologic surveys, detailed topographic mapping, four trench excavations, and test results from radiocarbon (14C) dating and optically stimulated luminescence (OSL), the following conclusions were drawn in this paper. The trenches uncovered five paleoseismic events in the past 5000 BP, including three paleoearthquake events since AD 1100 ± 70, occurring in AD 1100 ± 70, AD 1550 ± 100, and AD 1896. The latest three paleoearthquakes led to an accumulated 8.7 ± 0.5 m sinistral dislocation with a recurrence interval of approximately 400 y. This is consistent with the quasi-periodic earthquake recurrence behavior model. [ABSTRACT FROM AUTHOR]

The Tanjianshan Group, which was previously divided into a, b, c and d formations, has been controversial for a long time. It mainly distributes in the northern margin of Qaidam Basin and is an important early Paleozoic greenschist facies metamorphic volcanic sedimentary rock formation. Detailed field investigation and zircon LA-ICPMS U-Pb dating of the key strata suggest that the original lower part of a Formation (a-1) versus the original middle upper of d Formation (d-3 and d-4), the original upper part of a Formation (a-2) and b Formation versus the original lower part of d Formation (d-1 and d-2) of Tanjianshan Group are contemporaneous heterotopic facies volcanicclasolite deposit, respectively. The former formations formed during the middle-late Ordovician (463-458 Ma), while the latter ones formed in the late Ordovician (about 445 Ma). The original c formation of Tanjianshan Group, which formed after 430 Ma, is similar to the Maoniushan Formation of Kunlun Mountains and north Qaidam Basin. According to the rules of stratigraphic division and naming, new stratum formations of Tanjianshan Group are re-built and divided into Duancenggou (O1-2 td), Zhongjiangou (O2-3 tz) and Xitieshan (O3 tx) formations. The original c Formation is separated from Tanjianshan Group and is renamed as the Wuminggou Formation (S3-D1 w), which shows a discordant contact with underlying Tanjianshan Group and overlying Amunike Formation (D3 a). The zircon U-Pb age frequency spectrogram of Tanjianshan Group indicates three prominent peaks of 430 Ma, 460 Ma and 908 Ma, which is consistent with the metamorphic and magmatic crystallization ages obtained from para- and orthogneisses in north Qaidam HP-UHP metamorphic belt, implying that strong Caledonian and Jinningian tectonic and magmatic events have ever happened in North Qaidam. [ABSTRACT FROM AUTHOR]

In this paper we present new zircon U-Pb ages, whole-rock major and trace element analyses, and zircon Hf isotopic data for magmatic rocks in the Tuotuohe region of the western segment of the Jinshajiang suture. Our aim is to constrain the Early Permian-Late Triassic tectonic evolution of the region. Zircons from the magmatic rocks of the Tuotuohe region are euhedral-subhedral in shape and display fine-scale oscillatory zoning as well as high Th/U ratios (0.4-4.6), indicating a magmatic origin. The zircon U-Pb ages obtained using LA-ICP-MS are 281 ± 1 Ma, 258 ± 1 Ma, 244 ± 1 Ma, and 216 ± 1 Ma, which indicate magmatism in the Early Permian-Late Triassic. A diorite from Bashihubei (BSHN) has SiO2= 57.18-59.97 wt%, A12O3= 15.70-16.53 wt%, and total alkalis (Na2O + K2O) = 4.46-6.34 wt%, typical of calc-alkaline and metaluminous series. A gabbro from Bashibadaoban (BSBDB) belongs to the alkaline series, and is poor in SiO2 (45.46-54.03 wt%) but rich in A12O3 (16.19-17.39 wt%) and total alkalis (Na2O + K2O = 5.48-6.26 wt%). The BSHN diorite and the BSBDB gabbro both display an enrichment of LREEs and LILEs and depletion of HFSEs, and they have no obvious Eu anomaly; they have relatively low MgO contents (2.54-4.93 wt%), Mgs# values of 43 to 52, and low Cr and Ni contents (8.07-33.6 ppm and 4.41-14.2 ppm, respectively), indicating they differentiated from primitive mantle magmas. They have low Nb/U, Ta/U, and Ce/Pb ratios (1.3-9.6, 0.2-0.8, and 0.1-18.1, respectively), and their initial Hf isotopic ratios range from +9.6 to +16.9 (BSHN diorite) and +6.5 to +12.6 (BSBDB gabbro), suggesting their primary magmas were derived mainly from the partial melting of a mantle wedge that had been metasomatized by subduction fluids. Taking all the new data together, we conclude that the western and eastern segment of the Jinshajiang suture regions underwent identical processes of evolution in the Early Permian-Late Triassic: oceanic crust subduction before the Early Permian, continental collision during the Early-Middle Triassic, and post-collisional extension from the Late Triassic. [ABSTRACT FROM AUTHOR]

Located on the northeast margin of the Qiangtang terrane between the Jinshajiang suture zone and Bangonghu-Nujiang suture zone, the Dongmozhazhua and Mohailaheng Pb-Zn deposits in the Yushu area of Qinghai Province are representative Pb-Zn deposits of the Pb-Zn-Cu polymetallic mineralization belt in the northern part of the Nujiang-Lancangjiang-Jinshajiang area, which are in the front belt of the Yushu thrust nappe system. The formed environments of these two deposits are different from those of sediment-hosted base metal deposits elsewhere in the world. The authors hold that they were formed during the Indian-Asian continental collision and developed within the fold-thrust belt combined with thrust and strike-slip-related Cenozoic basins in the interior of the collisional zone. Studying on the metallogenic epochs of these two deposits is helpful to the understanding of ore-forming regularity of the regional Pb-Zn-Cu mineralization belt and also to the search for new deposits in this region. The age of the Dongmozhazhua deposit has been determined by the Rb-Sr isochron method for sphalerite residues, whereas the age of the Mohailaheng deposit has been determined by the Rb-Sr isochron method for sphalerite residues and the Sm-Nd isochron method for fluorite. The age of the Dongmozhazhua deposit is 35.0±0.0 Ma ((87Sr/86Sr)0=0.708807) for sphalerite residues. The age of the Mohailaheng deposit is 32.2±0.4 Ma ((87Sr/86Sr)0=0.708514) for sphalerite residues and 31.8±0.3 Ma ((143Nd/144Nd)0=0.512362) for fluorite with an average of 32.0 Ma. Together with the regional geological setting during mineralization, a possible tectonic model for metallogeny of the Dongmozhazhua and Mohailaheng Pb-Zn deposits has been established. These two ages are close to the ages of the Pb-Zn deposits in the Lanping and Tuotuohe basins, indicating that it is possible that the narrow 1000-kilometer-long belt controlled by a thrust nappe system on the eastern and northern margins of the Tibetan plateau could be a giant Pb-Zn mineralized belt. [ABSTRACT FROM AUTHOR]

Unlike many western countries, China is absolutely a freshman in emergency management and newly starts to set up Incident Command Systems (ICS) suitable for national situations by learning from those of America gradually. According to comparison of two cases, Gas Blowout Accident in 2003 and Yushu Earthquake in 2010, this article presents the development of ICS in last decade of China, shows some dilemmas it confronted and reveals the reasons we need to make standardization of ICS of our priority as well. [ABSTRACT FROM AUTHOR]

Recent large earthquakes in China (e.g., Wenchuan earthquake and Yushu earthquake) resulted in enormous damage to school buildings and took many students' lives. Recognizing the seismic vulnerability of existing school buildings, the Chinese government started a nationwide mission in 2009, aiming at increasing the seismic capacity of school buildings through inspection and retrofit activities. This paper presents the experiences of the authors in the retrofits of school buildings in which seismic isolation by using rubber and/or sliding bearings was adopted as a new and efficient retrofit technique, as compared with conventional ones. The retrofitted school buildings include masonry buildings, RC frame buildings, and a mixture of both. Design methods and the corresponding requirements in the modified seismic design code are presented, and typical construction procedures of the seismic retrofit are summarized from an engineer's point of view. Procedures regarding the contract and review of the retrofit projects are also introduced. To this end, a case study is made to demonstrate the proposed design and construction methods. The presented work provides references to the seismic retrofit of existing buildings. [ABSTRACT FROM AUTHOR]

Abstract: Background: On April 14, 2010, a catastrophic earthquake hit Yushu, China, causing 2698 deaths and 12,135 injuries. A large number of patients were evacuated by air to hospitals in unaffected areas for specialty treatment. Study Objective: To investigate the overall process and details of patients' aeromedical evacuation (AE) after the Yushu earthquake. Methods: The study was an observational, retrospective investigation conducted in December 2010 in Qinghai province. Information was gathered from Yushu Batang airport, the Ministry of Health, the Health Department of Qinghai Province, and rear echelon hospitals in five provinces. Results: A total of 2796 patients were evacuated by 152 separate flights from Yushu. The number of AE patients reached a peak (55.8%) within 72 h after the earthquake. Of the total 2796 patients, 2533 were admitted to rear echelon hospitals. This number included 2111 (83.3%) with earthquake-related trauma, 422 (26.7%) with non-traumatic diseases, and 166 (6.6%) with acute mountain sickness. No accident or medical error was reported during the evacuation process. The aircraft used for AE included IL-76 transport aircraft from the Air Force, Airbus A-319s from civil aviation, and MI-17 helicopters from Army aviation. According to our investigation, the need for professional AE training was great (83.7%). In addition, almost all participants (99.3%) agreed that the aircraft needed to be improved for the purpose of AE. Conclusions: Aeromedical evacuation of a large number of patients after major disasters in remote areas can be done safely and effectively; however, problems such as a lack of suitable AE aircraft and medical equipment, as well as insufficient professional medical training in AE, were revealed after the Yushu earthquake. [Copyright &y& Elsevier]

In the current study we investigated the prevalence and predictors of posttraumatic stress disorder (PTSD) among Chinese youths after an earthquake. A total of 753 middle school students participated in the survey and 99.5% of them were of Tibetan ethnicity. The University of California, Los Angeles PTSD Reaction Index was used to assess PTSD symptoms and a total of 101 participants were identified as probable PTSD cases. Independent predictors of PTSD included female sex, being injured, witnessing death, and derealization during the earthquake. Our results add to extant understanding of the impact of disasters on youth mental health, and carry implications for revising the current Criterion A2 of PTSD in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders. [ABSTRACT FROM AUTHOR]

The 14 April 2010 Ms = 7.1 Yushu Earthquake (YE) had caused severe damage in the Jiegu township, the residential centre of Yushu Tibetan Autonomous Prefecture, Qinghai Province, China. In view of the fragile geological conditions after YE, risk assessment of secondary geohazards becomes an important concern for the reconstruction. A quantitative methodology was developed to assess the risk of debris flow by taking into account important intensity information. Debris flow scenarios were simulated with respect to rainfall events with 10, 50 and 100 yr returning period, respectively. The possible economic loss and fatalities caused by damage to buildings were assessed both in the settlement area and in the low hazard settlement area regarding the simulated debris flow events. Three modelled building types were adopted, i.e. hollow brick wood (HBW), hollow brick concrete (HBC) and reinforced concrete (RC) buildings. The results suggest that HBC structure achieves a good balance for the cost-benefit relationship compared with HBW and RC structures and thus could be an optimal choice for most of the new residential buildings in the Jiegu township. The low hazard boundary presents significant risk reduction efficiency in the 100 yr returning debris flow event. In addition, the societal risk for the settlement area is unacceptable when the 100 yr returning event occurs but reduces to ALARP (as low as reasonably practicable) level as the low hazard area is considered. Therefore, the low hazard area was highly recommended to be taken into account in the reconstruction. Yet, the societal risk might indeed approach an unacceptable level if one considers that YE has inevitably increased the occurrence frequency of debris flow. The quantitative results should be treated as a perspective for the reconstruction rather than precise numbers of future losses, owing to the complexity of the problem and the deficiency of data. [ABSTRACT FROM AUTHOR]

The particular process of LCA (Lithosphere-Coversphere-Atmosphere) coupling referring to local tectonic structures and coversphere conditions is very important for understanding seismic anomaly from GEOSS (Global Earth Observation System of Systems). The LCA coupling based multiple-parameters analysis should be the foundation for earthquake prewarning. Three improved criterions: deviation notable enough, time quasi-synchronism, and space geo-adjacency, plus their quantify indices are defined for earthquake anomaly recognition, and applied to thermal parameters as a DTS-T (Deviation-Time-Space-Thermal) method. A normalized reliability index is preliminarily defined considering three quantify indices for deviation-time-space criterions. As an example, the DTS-T method is applied to the Ms 7.1 Yushu earthquake of 14 April 2010 in China. Furthermore, combining with the previous analysis of six recent significant earthquakes in the world, the statistical results regarding effective parameters, the occurrence of anomaly before the main shocks and a reliability index for each earthquake are introduced. It shows that the DTS-T method is reasonable and can be applied for routine monitoring and prewarning in the tectonic seismicity region. [ABSTRACT FROM AUTHOR]

By considering an area affected by a Ms 7.1 earthquake in Yushu Tibetan Autonomous Prefecture, Qinghai Province, in 2010 as an example, this paper analyzed the public response level after an earthquake disaster and discussed the principal factors influencing public response behaviors using a questionnaire survey. The results showed that the local public's response level is low in the studied area. The average response scoring rate is only 0.50. Gender, family income, experience and religion are the most significant factors influencing the public response level. Females or individuals with low family income and little education tend to have lower response capability and are more vulnerable during an earthquake disaster. Furthermore, on the whole, participants who had experience coping with unexpected safety events appear to adopt more reasonable response behavior during an earthquake disaster. The relatively undeveloped economy and low education level are the basic limiting factors for improving the public response capability in the studied area. Certain policies and suggestions to improve the response capability and disaster reduction were discussed. [ABSTRACT FROM AUTHOR]

We used interferometric SAR (InSAR) crustal deformation data sets to explore the fault slip involved in the 2010 April 14 (Mw = 6.9) Yushu earthquake modelled using angular dislocations. A refined rupture trace of the Yushu fault was extracted from two InSAR coseismic interferograms and field investigation results. We present a new method to discretize the fault geometry using triangular dislocation elements (TDEs), which are able to maintain consistency with the fault geometry modelled using rectangular dislocation elements (RDEs) and to avoid dislocation gaps and overlaps. Comprehensive comparisons between RDE and TDE models indicate that the classic Laplacian operator, which has not been carefully explored in many published studies, minimizes the slip on the boundary RDEs of the fault. A modification is proposed for the development of reasonable RDE models. The inversion shows that there were two larger concentrated slip zones during the Yushu earthquake. The largest was southeast of the hypocentre, near Luorongda, with a maximum slip of ∼1.6 m at the surface. The smaller slip patch was in the middle of the fault at a depth of ∼6 km, near the hypocentre. To improve the computational efficiency, we re-derived the analytic expressions for the strains associated with angular dislocations in an elastic half-space. The Coulomb stress changes increase at the northwestern and southeastern ends of the fault, and the small number of aftershocks in the southeast indicates that the seismic risk may be elevated in this area. [ABSTRACT FROM AUTHOR]

On 14 April 2010 at 07:49 (Beijing time), a catastrophic earthquake with Ms 7.1 struck Yushu County, Qinghai Province, China. A total of 2,036 landslides were interpreted from aerial photographs and satellite images, verified by selected field checking. These landslides cover about a total area of 1.194 km. The characteristics and failure mechanisms of these landslides are presented in this paper. The spatial distribution of the landslides is evidently strongly controlled by the locations of the main co-seismic surface fault ruptures. The landslides commonly occurred close together. Most of the landslides are small; there were only 275 individual landslide (13.5 % of the total number) surface areas larger than 1,000 m. The landslides are of various types. They are mainly shallow, disrupted landslides, but also include rock falls, deep-seated landslides, liquefaction-induced landslides, and compound landslides. Four types of factors are identified as contributing to failure along with the strong ground shaking: natural excavation of the toes of slopes, which mean erosion of the base of the slope, surface water infiltration into slopes, co-seismic fault slipping at landslide sites, and delayed occurrence of landslides due to snow melt or rainfall infiltration at sites where slopes were weakened by the co-seismic ground shaking. To analyze the spatial distribution of the landslides, the landslide area percentage (LAP) and landslide number density (LND) were compared with peak ground acceleration (PGA), distance from co-seismic main surface fault ruptures, elevation, slope gradient, slope aspect, and lithology. The results show landslide occurrence is strongly controlled by proximity to the main surface fault ruptures, with most landslides occurring within 2.5 km of such ruptures. There is no evident correlation between landslide occurrences and PGA. Both LAP and LND have strongly positive correlations with slope gradient, and additionally, sites at elevations between 3,800 and 4,000 m are relatively susceptible to landslide occurrence; as are slopes with northeast, east, and southeast slope aspects. Q al-pl, N, and T kn have more concentrated landslide activity than others. This paper provides a detailed inventory map of landslides triggered by the 2010 Yushu earthquake for future seismic landslide hazard analysis and also provides a study case of characteristics, failure mechanisms, and spatial distribution of landslides triggered by slipping-fault generated earthquake on a plateau. [ABSTRACT FROM AUTHOR]

The article presents abstracts on geological topics which include the 2010 earthquake in Yushu, Tibet, the crustal flow beneath the Tibetan Plateau, and slip-rates at the Karakorum fault.

The paper presents a wavelet transform method to identify possible seismic brightness temperature anomalies that might be associated with the Yushu (Ms = 7.1) earthquake that occurred in Qinghai province of China on 14 April 2010. Daily infrared data from the Chinese geostationary meteorological satellite FY-2E were used for the period from 1 January 2010 to 31 December 2011 and the spatial region 28.1-38.1° N by 91.7-101.7° E. We find that the wavelet transform is an effective method to analyse time series which contain nonstationary power, and identify here anomalous power both in the time and frequency domain. The results show that, over the two years, the relative wavelet power spectrum (RWPS) showed anomalous RWPS variations in nine cases: two of these were followed by earthquakes; seven were not. One of the two RWPS anomalies that were followed by an earthquake was in the southern area of the epicentre of the Yushu earthquake, with the RWPS anomaly starting to appear around 29 March 2010, decreasing in the period before the earthquake, and completely gone by 14 April 2010. The Yushu earthquake was the only strong earthquake within the region and two-year time period chosen, so the abnormal change of RWPS during this time period was possibly associated with the Yushu earthquake. [ABSTRACT FROM AUTHOR]

After the Yushu M7.1 earthquake on April 14, 2010, a large number of aftershocks were recorded by the surrounding permanent network and temporary seismic stations. Due to the distribution of stations, knowledge about velocity structure, the reliability of seismic phases, and so on, the location result from conventional method is usually of low precision, from which it is difficult to recognize the spatial and temporal distribution and the trends of aftershock activity. In this paper, by using teleseismic waveforms recorded by permanent station, the seismic velocity structure beneath the vicinity is obtained from receiver function stacking and inversion methods. And the Yushu earthquake sequences are relocated from seismic phase data by HypoDD. The results show that the Yushu M7.1 earthquake occurred at 13 km depth; the aftershock sequences were distributed mainly in the NWW along the Garzê-Yushu fault, and most aftershocks were concentrated in a 100 km length and 5-20 km depth. Combined with the velocity structure, it can be inferred that the earthquake mainly destroys the high-velocity layer of the upper crust. In the west of the seismic fault near (33.3°N, 96.2°E), the aftershock sequences were distributed like a straight column, suggesting there was a comminuted break from 25km depth to the ground. [ABSTRACT FROM AUTHOR]

Recent earthquakes such as the Haiti earthquake of 12 January 2010 and the Qinghai earthquake on 14 April 2010 have highlighted the importance of rapid estimation of casualties after the event for humanitarian response. Both of these events resulted in surprisingly high death tolls, casualties and survivors made homeless. In the Mw = 7.0 Haiti earthquake, over 200,000 people perished with more than 300,000 reported injuries and 2 million made homeless. The Mw = 6.9 earthquake in Qinghai resulted in over 2,000 deaths with a further 11,000 people with serious or moderate injuries and 100,000 people have been left homeless in this mountainous region of China. In such events relief efforts can be significantly benefitted by the availability of rapid estimation and mapping of expected casualties. This paper contributes to ongoing global efforts to estimate probable earthquake casualties very rapidly after an earthquake has taken place. The analysis uses the assembled empirical damage and casualty data in the Cambridge Earthquake Impacts Database (CEQID) and explores data by event and across events to test the relationships of building and fatality distributions to the main explanatory variables of building type, building damage level and earthquake intensity. The prototype global casualty estimation model described here uses a semi-empirical approach that estimates damage rates for different classes of buildings present in the local building stock, and then relates fatality rates to the damage rates of each class of buildings. This approach accounts for the effect of the very different types of buildings (by climatic zone, urban or rural location, culture, income level etc), on casualties. The resulting casualty parameters were tested against the overall casualty data from several historical earthquakes in CEQID; a reasonable fit was found. [ABSTRACT FROM AUTHOR]

Abstract: To investigate upper crust anisotropy, a tomography algorithm was reformulated to include lateral variations in both velocity and azimuthal anisotropy, and it was applied to Pg travel time data around the epicenter of the 14 April 2010 Ms=7.1 Yushu earthquake. A high-resolution two-dimensional (horizontal) seismic velocity and azimuthal anisotropy model was obtained using this simple tomography method including both station and event depth corrections. The results show clear anisotropy in the upper crust and it is as important as the velocity variation in explaining the travel time residuals. The most striking result is a high velocity anomaly with large anisotropy at the epicenter on the Yushu–Garze fault. The main rupture originated within this high velocity anomaly and propagated southeastward into a low velocity anomaly with small anisotropy at Yushu. The azimuthal anisotropy shows fast velocity direction along Yushu–Garze fault and larger anisotropy exists in the epicenter than surrounding regions. These results demonstrate a clear example that lateral variation and anisotropy in seismic structures of the upper crust controlled the origination (stress accumulation) and rupture propagation of the 2010 Yushu earthquake and distribution of aftershocks as well. The simple 2D Pg-wave travel time tomography method presented here introduces a new approach utilizing abundant aftershocks data for investigating the rupturing process of a major earthquake and possible fracture distribution around seismogenic zone. [Copyright &y& Elsevier]

Abstract: The 14 April 2010 Mw 6.9 Yushu earthquake ruptured the northwestern segment of the Ganzi-Yushu fault in Qinghai Province, China. Using GPS data obtained from 1999 to 2007 in the vicinity of the Ganzi-Yushu fault, we estimate the slip rates of the Fenghuoshan and Ganzi-Yushu faults, and the northwestern segment of the Xianshuihe fault as 6.1±1.9, 6.6±1.5, and 9.7±0.7mm/a for left lateral components, and 2.8±1.9, 1.7±1.6, and −2.0±0.9mm/a for shortening components, respectively. The Maduo-Gande fault slips left laterally at a rate of about 1–2mm/a, and ~3mm/a sinistral shear motion is left unexplained, possibly caused by deformation across one or more unknown faults in the region. These results agree with geological estimates of the fault slip rates, and show a progressive increase of shear motion from northwest to southeast across segments of the Xianshuihe–Ganzi-Yushu fault zone, implying variation in transferring and absorbing deformation in different regions in and around the Tibetan plateau. [Copyright &y& Elsevier]

Abstract: We applied a joint inversion of teleseismic data and InSAR measurements, aiming at obtaining a robust rupture process and slip distribution of the 2010 Yushu earthquake, through reducing the trade-off between slip timing and location. With the condition of the final static deformation of InSAR measurements, the rupture history can be achieved with more confidence. Surface offset constraint is also applied to our inversion. Through synthetic data inversion we find that InSAR data can resolve better fault slip at near surface depth range of 0–15km than teleseismic data; yet it has much poorer resolution at near hypocenter area, where teleseismic data has a relatively better resolution. Our final joint inversion results show that the 2010 Yushu earthquake has an essential rupture time around 20s, during which 90% of the seismic moment has been released. Two peak energy releasing moments occur at 8 and 12s after the earthquake initiation, respectively. The fault slip breaks the surface at most segments of the total 76km fault model and the maximum slip reaches 2.2m. We also find two peak-slip asperities, one at near hypocentral area, mainly distributed at depth around 10–15km; the other distributed in a large area at the eastern segments at near surface. Our most robust estimation of the seismic moment reaches 2.30×1019 N.m, equivalent to a moment magnitude of M w 6.9. [Copyright &y& Elsevier]

Abstract: We obtained the coseismic deformation field of the Ms7.1 earthquake in Yushu, Qinghai, China on 14 April 2010 using L band and C band SAR images. The results show that the deformation fields derived from L and C bands separately are consistent in general. They are all characterized by concentric elliptic interference fringes surrounding a NW trending fault with two local intensively deformed regions. Meanwhile they have small differences in area coverage of the deformation field, magnitude of LOS displacements and other details of deformation nearby the fault. The deformation from C band and L band covers 89∗59km square and 77∗43km square, with maximum displacements of about 45cm and 65cm in the radar line of sight, respectively. Using these two kinds of InSAR measurements separately and jointly, we constructed a three-segment fault model and inverted the coseismic fault slip of the Yushu event. The inversion results show that the slip distributions constrained by the two kinds of inSAR data are in agreement on the whole. They all indicate two concentration regions of slip distribution, one is located near the Jiegu town on the southeastern segment of the Yushu fault with a large area and the maximum slip of 2.4m, and the other is at the epicenter on the northwestern segment of the fault with a relatively small area. There are also discrepancies between the two kinds of slip distribution models. In general, the scale, magnitude, and depth of slip distribution constrained by C band ASAR data are larger than that by L band PALSAR data. The slip distribution from a joint inversion of the two kinds of SAR data is considered to be the most robust model compared to the results of that constrained by L band SAR data or C band SAR data alone. [Copyright &y& Elsevier]

On 14 April 2010, an Mw = 6.9 earthquake occurred in the Yushu county of China, which caused ~3000 people to lose their lives. Integrated with the information from the observed surface ruptures and aftershock locations, the faulting pattern of this earthquake is derived from the descending wide-swath and ascending strip mode PALSAR data collected by ALOS satellite. We used a layered crustal model and stress drop smoothing constraint to infer the coseismic slip distribution. Our model suggests that the earthquake fault can be divided into four segments and the slip mainly occurs within the upper 12 km with a maximum slip of 2.0 m at depth of 3 km on the Jiegu segment. The rupture of the upper 12 km is dominated by left-lateral strike-slip motion. The relatively small slip along the SE region of Yushu segment suggests a slip deficit there. The inverted geodetic moment is approximately Mw = 6.9, consistent with the seismological results. The average stress drop caused by the earthquake is about 2MPa with a maximum stress drop of 8.3MPa. Furthermore, the calculated static Coulomb stress changes in surrounding regions show increased Coulomb stress occurred in the SE region along the Yushu segment but with less aftershock, indicating an increased seismic hazard in this region after the earthquake. [ABSTRACT FROM AUTHOR]

Differential synthetic aperture radar interferometry (D-InSAR) can only measure one-dimensional surface displacements along the line-of-sight (LOS) direction which greatly inhibits its development and application. In this paper, we introduce a novel approach to measuring two-dimensional (2-D) surface displacements by exploiting a single InSAR pair, which is called multi-aperture InSAR (MAI) technology. We study the effects of baseline errors and the ionosphere on MAI technology and develop a directional filter and interpolator to minimize the ionospheric effects. A PALSAR image pair covering the 2010 Yushu earthquake is used to estimate the 2-D displacement fields of the earthquake using the MAI approach. The experimental results show that MAI is superior to conventional Offset-Tracking and therefore has great potential in co-seismic displacement measurement and source parameter inversion. [ABSTRACT FROM AUTHOR]

Background: On April 14, 2010, an earthquake registering 7.1 on the Richter scale shook Qinghai Province in southwest China. The earthquake caused numerous casualties and much damage. The epicenter, Yushu County, suffered the most severe damage. As a part of the psychological relief work, the present study evaluated the mental health statuses of the people affected and identified the mental disorder risk factors related to earthquakes. Methods: Five hundred and five earthquake survivors living in Yushu County were investigated 3-4 months after the earthquake. Participant demographic data including gender, age, marital status, ethnicity, educational level, and religious beliefs were collected. The Earthquake-Specific Trauma Exposure Indicators assessed the intensity of exposure to trauma during the earthquake. The PTSD Checklist-Civilian version (PCL-C) and the Hopkins Symptoms Checklist-25 (HSCL-25) assessed the symptoms and prevalence rates of probable Posttraumatic Stress Disorder (PTSD) as well as anxiety and depression, respectively. The Perceived Social Support Scale (PSSS) evaluated subjective social support. Results: The prevalence rates of probable PTSD, anxiety, and depression were 33.7%, 43.8% and 38.6%, respectively. Approximately one fifth of participants suffered from all three conditions. Individuals who were female, felt initial fear during the earthquake, and had less social support were the most likely to have poor mental health. Conclusions: The present study revealed that there are serious mental problems among the hard-hit survivors of the Yushu earthquake. Survivors at high risk for mental disorders should be specifically considered. The present study provides useful information for rebuilding and relief work. [ABSTRACT FROM AUTHOR]

On the morning of 14 April 2010, the Ms 7.1 Yushu earthquake struck the eastern Tibet Plateau and an Ms 6.3 aftershock followed west-southwest of the mainshock epicenter one and a half hours later. The Yushu earthquake occurred on the northwestern continuation of the Ganzi-Xianshuihe fault zone and reactivated two segments of the fault. Ruptures associated with Yushu earthquake span a zone ≈70 km long, extending from south of Jielong in the west to south of Gyêgu (Yushu) in the east. Detailed mapping of the surface rupture zone shows that it consists of two strike-slip segments, the western and eastern segments, separated by the Longbao Lake step-over (pull apart) basin. Our analysis suggests that the 18-km-long western segment of the surface rupture south of the Longbao Lake basin may have been associated with the Ms 6.3 aftershock. The eastern rupture segment, which is inferred to be associated with the mainshock, is 32 km long. The main surface rupture can also be divided into two sections, with a 2-km-long gap between them. The surface rupture exhibits left-lateral slip and is localized in a zone about 50 m wide along the present-day trace of the Yushu fault. A single break, without splays or branching traces, characterizes most of the surface rupture zone. The observed magnitudes of surface displacement are typically 0.5-1 m with a maximum slip of ≈2 m. Both field observations and seismic inversion results suggest, rupture of Ms 7.1 Yushu earthquake nucleated near the Longbao Lake step-over basin in the west, propagated unilaterally eastward, and terminated within the east segment margin of the Yushu fault. [ABSTRACT FROM AUTHOR]

The Yushu County, Qinghai Province, China, April 14, 2010, earthquake triggered thousands of landslides in a zone between 96°20′32.9″E and 97°10′8.9″E, and 32°52′6.7″N and 33°19′47.9″N. This study examines the use of geographic information system (GIS) technology and Bayesian statistics in creating a suitable landslide hazard-zone map of good predictive power. A total of 2,036 landslides were interpreted from high-resolution aerial photographs and multi-source satellite images pre- and post-earthquake, and verified by selected field checking before a final landslide-inventory map of the study area could be established using GIS software. The 2,036 landslides were randomly partitioned into two subsets: a training dataset, which contains 80 % (1,628 landslides), for training the model; and a testing dataset 20 % (408 landslides). Twelve earthquake triggered landslide associated controlling parameters, such as elevation, slope gradient, slope aspect, slope curvature, topographic position, distance from main surface ruptures, peak ground acceleration, distance from roads, normalized difference vegetation index, distance from drainages, lithology, and distance from all faults were obtained from variety of data sources. Landslide hazard indices were calculated using the weight of evidence model. The landslide hazard map was compared with training data and testing data to obtain the success rate and predictive rate of the model, respectively. The validation results showed satisfactory agreement between the hazard map and the existing landslide distribution data. The success rate is 80.607 %, and the predictive rate is 78.855 %. The resulting landslide hazard map showed five classes of landslide hazard, i.e., very high, high, moderate, low and very low. The landslide hazard evaluation map should be useful for environmental recovery planning and reconstruction work. [ABSTRACT FROM AUTHOR]

Abstract: Objective: By analysing the injuries of the orthopaedic wounded during the 2010 Yushu earthquake, we aim to provide useful medical information for the rational application and allocation of medical resources and better implementation of medical relief in earthquake-stricken areas. Patients and methods: Five hundred and eighty-two orthopaedic patients injured during the earthquake. The clinical data, injury conditions and epidemiological features (including age composition, gender ratio, distribution of injury, etc.) were collected and analysed. Results: Altogether 582 orthopaedic patients were analysed. The average age for all patients was 38.8±13.08 years (0–86 years). Adults accounted for 81.62%. There was no gender difference. The most common injuries included limb fractures, pelvic/acetabular fractures and spinal fractures. Fractures accompany with nerve injury were relatively low, only 17 patients account for 2.92%. Fractures complicated by crush syndrome were even lower, only 7 patients account for 1.20%. Conclusion: The patients who experienced fractures in the Yushu earthquake were mostly adults. This was correlated with population composition in Yushu area. This time all the orthopaedic injuries were relative mild with less complication as nerve injury or crush syndrome mainly because of the characteristics of the house structure in Yushu area. [Copyright &y& Elsevier]

The Yushu Ms 7.1 earthquake occurred on April 14, 2010 in Qinghai Province, China. It induced a mass of secondary geological disasters, such as collapses, landslides, and debris flows. Risk assessment maps are important for geological disaster prevention and mitigation, and also can serve as a guide for post-earthquake reconstruction. Firstly, a hazard assessment index system of secondary geological disasters in the earthquake region was built in this paper, which was based on detailed analysis of environmental and triggering factors closely related to geological disasters in the study area. GIS technology was utilized to extract and analyze the assessment index. Hazard assessment maps of secondary geological disasters were obtained by spatial modeling and overlaying analysis. Secondly, an analysis of the vulnerability of hazard bearing bodies in the area was conducted, important information, such as, population density, percentage of arable land, industrial and agricultural outputs per unit area were regarded as assessment indices to evaluate socioeconomic vulnerability. Thirdly, the risk level of secondary geological disasters of the area was obtained by the formula: Risk=Hazard × Vulnerability. Risk assessment maps were categorized into four levels, including 'low', 'moderate', 'high' and 'very high'. These results show that some urban areas are at very high risk, including Jiegu, Chengwen, Xiaxiula and Sahuteng towns. This research can provide some references and suggestions to improve decision-making support for emergency relief and post-earthquake reconstruction in the study area. [ABSTRACT FROM AUTHOR]

Adolescents who have suffered through earthquakes often experience symptoms of posttraumatic stress disorder (PTSD). This particular population has received increasing attention from researchers. The goals of the present study are to describe longitudinally the prevalence and the severity of PTSD in adolescent survivors of the Yushu earthquake in China and to explore the risk factors which lead to psychiatric disorders. The PTSD Check List (Civilian Version) was used to assess the PTSD symptoms in participants. The rates of PTSD were found to be 10.9% after 6 months and 5.8% after 24 months. Bereavement, being buried in the ruins and personal injury were found to be significant risk factors for the development of PTSD. We suggest that intervention strategies should be addressed and more attention should be paid to adolescents. [ABSTRACT FROM AUTHOR]