China Earthquake Research Articles

Spatial Weibull regression with multivariate log gamma process and its applications to China earthquake economic loss

Spatial Weibull regression with multivariate log gamma process and its applications to China earthquake economic loss

Deep metallogenic mechanism in southeastern Chinabased on receiver function data

Crustal deformation and deep metallogenic mechanisms in southeastern (SE) China are still debated. In this study, we applied the receiver function method to measure crustal thickness and Poisson's ratio for crustal rock using teleseismic data recorded at 207 seismic stations from China Earthquake Administration Network. The results showed that crustal thickness varied from ~27 km in the eastern part to ~43 km in the western part of the study area, with an average crustal thickness of 31 km. The crust is thick in the west and thin in the east. The observed Poisson's ratio for crustal rock was relatively high in the southern Cathaysia Block (CB), with an average of 0.295, while in the Qinling—Dabie terrane, it was relatively low, with an average of 0.257. In the middle of the Yangtze craton and central east of the CB, Poisson's ratio for crustal rock varied from 0.257 to 0.286. By comparing Poisson's ratio of the intrusive deposits with that of igneous rocks in volcanic complexes, we deduced that the metallic mineral system might be associated with orogenic and hydrothermal deposits. These results indicated that multistage magma and mineralization in the study area might be attributed to the tectonic-magma-thermal event. The high Poisson's ratio for crustal rock in the southeastern margin of the CB and northeastern Upper Yangtze Cratonmight be related to Mesozoic lower crustal mafic partial melt, which provides an important environment for various magmatic intrusions and metallogenies.

Factors related to early and rapid assessment of in-hospital mortality among older adult trauma patients in an earthquake

There is limited evidence for emergency physicians and emergency trauma surgeons regarding the determinants of early and rapid assessment of older adult in-hospital mortality due to earthquakes. This study explored factors related to the early and rapid assessment of the mortality among older adult earthquake trauma patients (OAETPs) and created a screening model. Data on 7,308 OAETPs from the West China Earthquake Patients Database were analyzed retrospectively. The 35 variables that can be obtained rapidly on arrival at the hospital were collected. Least absolute shrinkage and selection operator (LASSO) regression analysis was performed. Then, the nomogram for assessing the mortality of OAETPs was constructed. We identified 10 independent mortality-related factors that contributed to the in-hospital mortality of OAETPs. The 10 factors included age (odds ratio [OR]=1.061, 95% confidence interval [CI]:1.031-1.090), dementia (OR=5.146, 95%CI: 1.169-17.856), coronary heart disease (CHD; OR=23.441, 95%CI: 4.799-83.927), malignant tumor (OR=8.497, 95%CI: 3.583-17.967), deep vein thrombosis (DVT; OR=7.110, 95%CI: 1.369-27.168), chronic kidney disease(CKD; OR=11.783, 95%CI: 5.419-24.407), pulse rate (PR; OR=1.036, 95%CI: 1.022-1.048), mean artery pressure (MAP; OR=0.960, 95%CI: 0.945-0.975), Glasgow Coma Scale (GCS; OR=0.864, 95%CI: 0.760-0.972), and Triage Revised Trauma Score (T-RTS, OR=0.485, 95%CI: 0.351-0.696). The 10 mortality-related factors could be quickly obtained on hospital arrival and should be the focal point of future earthquake response strategies regarding hospitalized older adults with trauma. A nomogram was constructed based on the factors for screening OAETPs with a higher risk of in-hospital mortality.

Male adolescents with Interleukin 10 rs1800872 AA genotype had higher prevalence and slower recoveries of post-traumatic stress disorder at late stage of a follow-up

BackgroundPathophysiological mechanisms of post-traumatic stress disorder (PTSD) are elusive and heterogeneous relationships have been reported among PTSD, Interleukin 10 (IL-10), and other factors after stresses. The present study aimed to longitudinally investigate associations of PTSD with environmental factors and genetic variation of rs1800872 at IL-10 gene. MethodsSymptoms of PTSD were measured by PTSD Checklist-Civilian Version (PCL-C) in 462 high school students at 6, 12, and 18 months after Wenchuan earthquake in China. Genotypes of IL-10 rs1800872 were identified by polymerase chain reaction-restriction fragment length polymorphism analysis and verified by DNA sequencing. ResultsAA homozygotes had higher PTSD prevalence than C allele carriers only at 18 months in male, but not female subjects. PTSD prevalence at 18 months was lowered in all subjects except male AA homozygotes when compared to that at 6 months, and only in female C allele carriers when compared to that at 12 months. PCL-C scores at 18 months were decreased in all students but not in male AA homozygotes when compared to those at 6 months. IL-10 rs1800872 was associated with PTSD at 18 months. Patterns of predictors of PCL-C scores were different between AA homozygotes and C allele carriers at different times during the follow-up. ConclusionThere were different reciprocal actions of IL-10 rs1800872 with other potential factors or predictors on PTSD in a time-course and gender-dependent manner. Male students with IL-10 rs1800872 AA genotype had higher prevalence and slower recoveries of PTSD at late stage of the follow-up, suggesting requirements of special psychiatric care or drug supplementation at this stage.

Dynamic emergency inspection routing and restoration scheduling to enhance the post-earthquake resilience of a highway–bridge network

In the immediate aftermath of earthquakes, effective scheduling of emergency restoration for transportation networks depends fundamentally on information about damage to those networks, which for the most part can only be acquired via a lengthy process of inspection. This paper proceeds from the insight that, rather than waiting to commence restoration activities until after all inspection activities are completed, damage information revealed gradually via inspection efforts could be incorporated into parallel scheduling of inspection routes and restoration schedules, allowing inspection and restoration to occur simultaneously, thus more efficiently boosting transportation networks’ resilience. To achieve this, however, it will be necessary to understand the real-time interaction between inspection and restoration, as well as such interaction's impacts on the inspection-routing and restoration-scheduling process. Assuming that multiple inspection and restoration crews operate simultaneously and that their optimal routes and schedules are updated dynamically whenever additional inspection information is obtained, this study proposes an integer program for modeling inspection-routing and restoration-scheduling problems and determining the optimal inspection routes and restoration schedules for damaged highway–bridge networks, with the specific aim of maximizing a resilience measure, network travel time. The results of a case study using the proposed method and data from the 2008 Wenchuan Earthquake in China show that, as compared to a traditional inspection-restoration model, simultaneously performing and dynamically scheduling inspection and restoration can significantly boost networks’ resilience.

Post-disaster trauma and cultural healing in children and adolescents: Evidence from the Wenchuan earthquake

This study combines quantitative and qualitative methods, used non-verbal, sandplay work with children and adolescents to understand the psychological changes and features of trauma and healing amongst children and adolescents after the Wenchuan earthquake in China. Coding analysis and symbolic analysis were performed for 96 initial sandplay works by children and adolescents who had experienced the Wenchuan earthquake, at 1, 6, 12, 18, and 24 months respectively after the earthquake. The trauma scores at 1 and 6 months were significantly lower than those recorded at 12, 18, and 24 months after the earthquake. The highest incidence of traumatic themes shown in the sandplay works was “split” (65%). The highest incidence of healing themes was “energy” (76%). The most used sandplay miniatures were animal (83%), people (76%), plant (75%), and building (75%), of which the most frequently used animals were turtles, goats, and butterflies; the most frequently used human characters were angels; and the most frequently used buildings were houses. Those children and adolescents suffered the most severe mental trauma at approximately 12–18 months after the earthquake. Culture is a psychological resource that can help heal the trauma caused by natural disasters. Psychological assistance needs to be continued over several years and emphasis should be placed on the establishment of four therapeutic stages: relationship, connection, trust, and freedom.

Largest scale successful real-time evacuation after the Wenchuan earthquake in China: lessons learned from the Zengda gully giant debris flow disaster

A catastrophic debris flow occurred in the Zengda gully, a branch of the Dajinchuan River in Zengda town, Jinchuan County, Sichuan Province, China. The successful implementation of a real-time evacuation avoided 820 casualties for people living in 200 settlements. This was the largest-scale successful real-time evacuation for a debris flow disaster after the Wenchuan earthquake in China. In order to better reveal the causes of the successful real-time evacuation process of the giant debris flow disaster, the characteristics, formation and movement process of the debris flow were studied using multi-temporal remote sensing images, field investigation, laboratory analysis, and empirical formula calculations. It was found that the successful real-time evacuation was possible because of a well-executed monitoring system, timely release of early warning information, a highly effective operation disaster prevention system, and decisive and advanced avoidance. It also transferred strategies through in-depth analysis of several important stages in the real-time evacuation process. Finally, an exemplary mode of community-based warning is proposed based on the Zengda gully giant debris flow disaster real-time evacuation. Specifically, the mode was led by government, implemented by local residents and proceeded with the guidance by experts in the field. The experience and effective risk avoidance mode presented in this paper can be shared and employed by other countries or regions at serious risk for debris flow disasters.

Physics-based large-deformation analysis of coseismic landslides: A multiscale 3D SEM-MPM framework with application to the Hongshiyan landslide

A multiscale framework is developed based on the spectral element method (SEM) and material point method (MPM) for the large-deformation analysis of coseismic landslides. At a regional scale, SEM is used to model elastic wave propagation from a seismic source to a local site with complex topography. At a local scale, the coseismic landslide process and large deformation behavior are simulated by a nonlinear MPM model. Therefore, the proposed SEM-MPM model is able to reproduce the entire coseismic landslide process, including triggering, sliding and deposition. In this study, the coupled SEM-MPM method is used to simulate the massive Hongshiyan landslide triggered by the 2014 Ms6.5 Ludian earthquake in China. The study shows that the domain reduction method is able to reproduce the complex wave field across the SEM and MPM platforms, especially the strong topographic amplification of ground motion on the mountain ridge, which triggered the catastropic failure of the Hongshiyan landslide. The simulated volume of the sliding mass, sliding velocity, and final deposition profile are comparable with the field data and previous numerical studies, showing that the SEM-MPM method is a promising physics-based numerical tool for an integrated study of coseismic landslides.

The LAI Coupling Associated with the M6 Luxian Earthquake in China on 16 September 2021

Periodic signals replaced noise that was found in continuous seismic data, particularly in the nighttime, from the broadband seismometer at the MVP-LAI (monitoring vibrations and perturbations in the lithosphere, atmosphere and ionosphere) system before the occurrence of the Luxian earthquake on 16 September 2021. A short distance of ~150 km between the MVP-LAI system and the epicenter of the Luxian earthquake suggests the periodic singles as promising seismo-phenomena, due to that the radius of the earthquake preparation zone is ~380 km for an M6 event. Integration of geophysical parameters, including atmospheric pressure, vertical electric field, radon concentration, groundwater level and precipitation, at the MVP-LAI system provides an excellent opportunity for studying the seismo-LAI coupling associated with the Luxian earthquake. Analytical results show that ground vibrations, atmospheric pressure and total electron content varied from ~10−3 to ~10−2 Hz before the Luxian earthquake. The seismo-LAI coupling in the relatively low frequency band (~10−3 Hz) can be referred to as the acoustic-gravity waves triggered by the amplified ground vibrations. In contrast, the seismo-LAI coupling in a relatively high frequency band (~10−2 Hz) would be caused by micro-cracks and/or the high-mode natural frequency that further drives changes of TEC due to the atmospheric resonance.

Factors controlling the spatial distribution of coseismic landslides triggered by the Mw 6.1 Ludian earthquake in China

Understanding the spatial distribution regularity of coseismic landslides is important for mitigation in future earthquakes. Unveiling the controlling factors of the distribution of coseismic landslides is a long-standing unsolved problem. On 3 August 2014, a Mw 6.1 earthquake occurred in Ludian County, Yunnan Province, China, and resulted in a great number of landslides and substantial losses. The coseismic landslide distribution in this earthquake, which was triggered by an unmapped fault, shows a different pattern. This paper conducted a spatial analysis to reveal the controlling factors in the Ludian earthquake. A spatial database of landslides has been built by interpreting the ZY-3 pre-earthquake, unmanned aerial vehicle (UAV), GeoEye-1 and GF-1 post-earthquake. A total of 1414 landslides were identified after a combination of image interpretation and field investigation in an area of 704.7 km2. The geological setting of the study area, including the tectonics and lithology, has been mapped in detail. The digital elevation model (DEM) of the study area with a resolution of 30 m × 30 m was presented to address the topographic characteristics. A geographic information system (GIS) was used to analyse the spatial characterization of the landslides. Correlations between the occurrences of landslides and factors, i.e., slope gradient, elevation, slope aspect, intensity, distance to coseismic fault, distance to the epicentre, lithology, distance to non-coseismic faults, distance to rivers and distance to road, were characterized with a spatial analysis in GIS. It can be concluded that the slope gradient and the distance to the coseismic fault are the two most important factors for determining the spatial distribution of coseismic disasters. Some other factors play a role by influencing the slope gradient to a certain extent, and the movement of the coseismic fault is the prone direction of coseismic landslides. Slope cutting fractures the rock mass, increases the slope gradient, and significantly increases the occurrence of coseismic landslides. A statistics analysis indicates that the landslide concentration (LC) generally has an obvious exponential decrease with an increasing distance to the coseismic fault, while it has a good Weibull cumulative distribution with the slope gradient.

Seismic sentinel? An analysis of captive giant panda behavior in response to the Lushan earthquake in China

It is widely believed that various animal species can sense and respond to the geophysical stimuli that precede earthquakes, especially electromagnetic fields, although supporting field evidence is mostly anecdotal. Here we report on the reactions of four female giant pandas under observation over the three days prior to the Lushan (30.1°N, 103.0°E) magnitude 7.0 earthquake that occurred in Sichuan province, China, on April 20, 2013. We observed no significant generalized behavioral anomalies indicative of them perceiving an impending earthquake. We also observed no startle behaviors in the 5 s prior to tremors commencing, indicating that these pandas either did not detect or did not respond to precursor P-waves. Our findings suggest that although giant pandas have evolved in, and continue to occupy exclusively, a seismically active range in central China, they do not appear to perceive pre-earthquake geophysical warning signs.

Tectonic Block Model of Continental Earthquakes in China: Twenty-years Retrospective

Abstract At the beginning of the 21st century, the ‘active tectonic block model’, described by hierarchical crustal tectonic blocks, was proposed to explain the distribution of continental earthquakes in China. The blocks, as well as the block boundary zones, were determined by geological, geophysical, and geodetic observations. The model, indicating that large earthquakes, especially great earthquakes, occur mainly in the boundary zones, plays an important role in seismic hazard assessment and earthquake forecast in China. The model has been tested by the seismicity in continental China in the past 20 years. Meanwhile, with new data accumulating and new technology emerging, it is possible to update the model into a new version, e.g., from 2D to 3D by considering deep structures such as crustal channel flow, and from a kinematic model to a dynamic one by computational geodynamics. The updated model could also be applied to broader continental regions for international collaborative and comparative studies.

Extraction and Discrimination of MBT Anomalies Possibly Associated with the Mw 7.3 Maduo (Qinghai, China) Earthquake on 21 May 2021

Earthquakes are one of the most threatening natural disasters to human beings, and pre- and post-earthquake microwave brightness temperature (MBT) anomalies have attracted increasing attention from geosciences as well as remote sensing communities. However, there is still a lack of systematic description about how to extract and then discriminate the authenticity of seismic MBT anomalies. In this research, the first strong earthquake occurring near the northern edge of eastern Bayan Har block in nearly 20 years, the recent Mw 7.3 Maduo earthquake in Qinghai province, China on 21 May 2021, was selected as a case study. Based on the monthly mean background of MBT, the spatiotemporal features of MBT residuals with 10.65 GHz before and after the earthquake was firstly revealed. Referring to the spatial patterns and abnormal amplitudes of the results, four typical types of evident MBT positive residuals were obtained, and the time series of intensity features of each category was also quantitatively analyzed. Then, as the most influential factor on surface microwave radiation, air temperature, soil moisture and precipitation were analyzed to discriminate their contributions to these residuals. The fourth one, which occurred north to the epicenter after the earthquake, was finally confirmed to be caused by soil moisture reduction and thus ruled out as being related to seismicity. Therefore, the three retained typical MBT residuals with 10.65 GHz could be identified as possible anomalies associated with the Maduo earthquake, and were further analyzed collaboratively with some other reported abnormal phenomena related to the seismogenic process. Furthermore, through time series analysis, the MBT positive residuals inside the Bayan Har block were found to be more significant than that outside, and the abnormal behaviors of MBT residuals in the elevation range of 4000–5000 m reflected the shielding effect on microwave radiation from thawing permafrost on the plateau in March and April, 2021. This research provides a detailed technique to extract and discriminate the seismic MBT anomaly, and the revealed results reflect well the joint effect of seismic activity and regional coversphere environment on satellite-observed MBT.

The Medium-to-Short-Term Earthquake Predictions in China and Their Evaluations Based on the R-Score

Abstract The earthquake tendency consultations in China, which have been carried out by the China Earthquake Administration for more than 40 yr, are really forward prediction of earthquakes. The results, experiences, and data accumulation are valuable for seismic researches. In this article, the annual, monthly, and weekly predictions produced by the regular earthquake tendency consultations and the rapid postearthquake tendency prediction derived from the irregular ones are presented systematically. In the regular predictions, the areas where earthquakes tend to occur are identified by specific space–time windows. To evaluate the efficiency of the predictions, we apply the R-score method to all the medium-to-short-term efforts. The R-score has been used as a routine tool to test annual predictions in China, in which the hit rate and the percentage of spatial alarms over the whole territory are taken into consideration. Results show that the annual R-scores, during the period of 1990–2020, increased gradually, with the average of 0.293. The examples in 2018 indicate that a considerable proportion of earthquakes with the Ms 5.0 and above were detected by the annual prediction; some earthquakes were detected by the monthly prediction, whereas just only a few earthquakes could be detected by the weekly prediction. The corresponding R-scores are 0.46, 0.11, and 0.002, decreasing obviously with reduction of the prediction time windows, and the smallest one, which is very close to zero, may suggest the minimum time scale for an effective earthquake prediction. We also evaluated efficiency of the irregular predictions by analyzing the practices of 29 Ms≥5.0 earthquakes since January 2019 and found that it is highly possible to do rapid postearthquake tendency prediction in China.

Does disaster knowledge affect residents' choice of disaster avoidance behavior in different time periods? Evidence from China's earthquake-hit areas

Based on the survey data of 327 peasant households in Wenchuan and Lushan earthquakes in China, this study analyzed the characteristics of residents' disaster knowledge and their disaster avoidance behavior before, during and after the earthquake, and constructed the binary Logit model and the disordered multi-classification logistic regression model to explore the impact of disaster knowledge on residents' disaster avoidance behavior in different periods. The results show that:(1) Generally speaking, the residents have strong disaster knowledge. Among them, 55% of the residents have good basic knowledge of disasters, 66% and 68% of the residents have sufficient knowledge of emergency response skills and resistance skills, respectively. (2) Before the earthquake, residents' awareness of disaster preparedness was poor; When an earthquake occurs, the number of residents who choose to leave their houses immediately (60%) is the largest, while the number of residents who choose to continue to do things (5%) is the least. After the earthquake, the highest percentage of residents (40%) chose to evacuate again to a safer place, while the lowest percentage (7%) chose to continue with their work. (3) The regression results show that the stronger the disaster knowledge is, the better the disaster preparedness will be. When a disaster occurs, compared with the residents who evacuate their houses immediately, the residents who do not have sufficient knowledge of the disaster are more willing to continue to do things. Residents without adequate disaster knowledge are more likely to stop doing things and stay put than to evacuate their homes immediately. After a disaster occurs, residents with less knowledge of the disaster are more likely to stay put and wait for the latest information and confirmation that their families are safe than those who evacuate again to a safer place. Residents with stronger disaster knowledge were more likely to continue their work than those who had to evacuate again to a safer place.

Assessment and determination of earthquake casualty gathering area based on building damage state and spatial characteristics analysis

Timely determination of the spatial distribution of post-earthquake relief forces and appropriate levels of response is a daunting task. This paper proposes a method based on building damage state and spatial characteristics analysis to assess the hotspot distribution of earthquake casualties and determine the dangerous gathering area. The method comprises three steps: (1) use the basic information of the buildings in the study area to calculate the building damage state and build the relationship with the casualties; (2) mesh the research area and establish the mapping relationship with the casualties caused by the building damage; (3) use grid data for spatial autocorrelation analysis (Moran's I) and hotspot analysis (Getis-Ord Gi*) to comprehensively assess the casualty cluster area. The feasibility of the proposed method was validated using the seismic damages of Longtoushan Town in the 2014 Ludian earthquake of China. The damage state of buildings and the number of casualties evaluated by this method coincide quite well with the actual earthquake results, and the casualty concentration area is determined. This method quantifies the degree of spatial risk aggregation of casualties and provides scientific guidance for disaster prevention planning and rescue.

Aftershock sequence of the 2017 Mw 6.5 Jiuzhaigou, China earthquake monitored by an AsA network and its implication to fault structures and strength

SUMMARY We deployed a seismic network near the source region of the 2017 Mw 6.5 Jiuzhaigou earthquake to monitor aftershock activity and to investigate the local fault structure. An aftershock deployment of Array of small Arrays (AsA) and a Geometric Mean Envelop (GME) algorithm are adopted to enhance detection performance. We also adopt a set of association, relocation and matched-filter techniques to obtain a detailed regional catalogue. 16 742 events are detected and relocated, including 1279 aftershocks following the Mw 4.8 aftershock. We develop a joint inversion algorithm utilizing locations of event clusters and focal mechanisms to determine the geometry of planar faults. Six segments were finally determined, in which three segments are related to the Huya fault reflecting a change in fault dip direction near the main shock hypocentre, while the other segments reflect branches showing orthogonal and conjugate geometries with the Huya fault. Aftershocks were active on branching faults between the Huya and Minjiang faults indicating that the main shock may have ruptured both major faults. We also resolve a fault portion with ‘weak strength’ near the main shock hypocentre, which is characterized by limited coseismic slips, concentrated afterslip, low aftershock activities, high b-value and high sensitivity to stress changes. These phenomena can be explained by fault frictional properties at conditional stable sliding status, which may be related to the localized high pore-fluid pressure produced by the fluid intrusion.

A real-time AI-assisted seismic monitoring system based on new nodal stations with 4G telemetry and its application in the Yangbi MS 6.4 aftershock monitoring in southwest China

A rapidly deployable dense seismic monitoring system which is capable of transmitting acquired data in real time and analyzing data automatically is crucial in seismic hazard mitigation after a major earthquake. However, it is rather difficult for current seismic nodal stations to transmit data in real time for an extended period of time, and it usually takes a great amount of time to process the acquired data manually. To monitor earthquakes in real time flexibly, we develop a mobile integrated seismic monitoring system consisting of newly developed nodal units with 4G telemetry and a real-time AI-assisted automatic data processing workflow. The integrated system is convenient for deployment and has been successfully applied in monitoring the aftershocks of the Yangbi MS 6.4 earthquake occurred on May 21, 2021 in Yangbi County, Dali City, Yunnan in southwest China. The acquired seismic data are transmitted almost in real time through the 4G cellular network, and then processed automatically for event detection, positioning, magnitude calculation and source mechanism inversion. From tens of seconds to a couple of minutes at most, the final seismic attributes can be presented remotely to the end users through the integrated system. From May 27 to June 17, the real-time system has detected and located 7 905 aftershocks in the Yangbi area before the internal batteries exhausted, far more than the catalog provided by China Earthquake Networks Center using the regional permanent stations. The initial application of this integrated real-time monitoring system is promising, and we anticipate the advent of a new era for Real-time Intelligent Array Seismology (RIAS), for better monitoring and understanding the subsurface dynamic processes caused by Earth's internal forces as well as anthropogenic activities.

Atmospheric Anomaly Analysis Related to Ms > 6.0 Earthquakes in China during 2020–2021

The attention towards links of atmospheric parameter variation and earthquakes has increased exponentially by utilizing new methods and more accurate observations. Persistent research makes it possible to gain insight into the precursor mechanism of earthquakes. In this paper, we studied the universality of detecting atmospheric anomalies associated with earthquakes based on tidal force fluctuation in China for earthquakes of Ms > 6.0, and explored the influence of tidal force on tectonic stress. The data of air temperature, geopotential height, ozone mixing ratio, and relative humidity from the National Center for Environmental Prediction (NCEP) were analyzed to reveal the spatiotemporal variation of atmospheric anomalies at multiple isobaric surfaces. Furthermore, the coupling of atmospheric parameters was investigated. The results showed that continuous solicitation exerted by tidal forces could change the strength of tectonic stress that causes earthquakes. The evolution pattern of air temperature, geopotential height, and relative humidity could be supported by atmospheric thermal vertical diffusion, while the anomalies of ozone mixing ratio was not evident. This verified the feasibility of detecting multi-parameter atmospheric anomalies associated with earthquakes based on tidal force fluctuation. Our results provide more evidence for understanding the atmospheric precursor characteristics of earthquakes.

Associations Between Strong Earthquakes and Local Rainfall in China

Strong earthquakes are a major cause of natural disasters and may also be related to heavy rainfall events. Both phenomena have received considerable attention in seismology and meteorology, two relatively independent disciplines, but we do not yet know whether there is a connection between them. We investigated the characteristics of daily rainfall over seismic areas in China. Our statistical analyses showed that there is a strong correlation between strong earthquakes (Ms ≥ 6.0) and rainfall over the seismic area, with 74.9% of earthquakes in China accompanied by seismic epicenter rainfall and 86.6% by seismic area rainfall. The statistics also showed that the daily precipitation over the seismic area, including the epicenter, was mainly light rain, with only a few instances of torrential or storm rain, with 80% of the rainfall events lasting two or more days. The maximum cumulative precipitation corresponded well with the strong earthquakes occurring over steep terrain, such as the Taiwan central mountains and the eastern Tibetan Plateau. The earthquake area rainfall had a higher frequency than the 30-years climatological average and was dominated by earthquake events in the wet season. The WRF-ARW numerical simulation of seismic local rainfall during the devastating Ms 8.0 Wenchuan earthquake in May 2008 showed that the geothermal heat from the earthquake strengthened the local convergence of moisture and vertical motion near the epicenter and the upward transport of the sensible heat flux, which favored seismic rainfall. The results of this study show that rainfall in the seismic area is closely related to strong earthquakes and can be triggered and enhanced by geothermal heat.