The paper presented a new regular pattern (network structure ) of great earthquakes occurred in China's Mainland during the past 700 years, which may be helpful to improve the understanding of great earthquakes ...The paper presented a new regular pattern (network structure ) of great earthquakes occurred in China's Mainland during the past 700 years, which may be helpful to improve the understanding of great earthquakes and can serve as a base for the study of prediction of future great earthquakes. It can be done because there are quite complete and confident records of historical and recent earthquakes in a wide extent in China.展开更多
We collect seismic moment tensors of the earthquakes occurring from 1900 to 2013 in and around the Chinese mainland and summarize the surface ruptures and displacements of 70 earthquakes with M S≥7. 0. We divide thes...We collect seismic moment tensors of the earthquakes occurring from 1900 to 2013 in and around the Chinese mainland and summarize the surface ruptures and displacements of 70 earthquakes with M S≥7. 0. We divide these large earthquakes into three types. Type A contains earthquakes with surface ruptures and displacements. Type B is earthquakes without displacements and Type C is those without any of this data. We simulate a triangular distribution of displacements for Type B and C. Then,we segment these large earthquakes by using their displacements and surface ruptures. Finally,kinematic models are determined from earthquake data and Bicubic Bessel spline functions. The results show that,first of all,the reasonability and spatial consistency of defined models are advanced.Strain rates have better continuity and are comparable with geologic and geodetic results in Himalaya thrust fault zones. The strain rates decrease in the Tarim basin and the Altun Tagh fault zones because of their low seismicity. The direction of compressional deformation in Gobi-Altay is changed from SE to NE and its extensional direction is changed from NE to NW. The extensional deformation in the Ordos block is diminished obviously. Secondly,earthquakes account for 30- 50% of expected motion of India relative to Eurasia determined from the NUVEL-1A model,with a missing component of 20 mm / a which may contain aseismic deformation such as fault creep and folds,the missing parts of earthquake data and elastic strain energy released by potential earthquakes.展开更多
A major earthquake occurrence zone means a place where M ≥6 events have occurred since the Holocene and similar shocks may happen again in the future. The dynamic context of the major earthquake occurrence zones in C...A major earthquake occurrence zone means a place where M ≥6 events have occurred since the Holocene and similar shocks may happen again in the future. The dynamic context of the major earthquake occurrence zones in China is primarily associated with the NNE-directed push of the India plate, next with the westward subduction of the Pacific plate. The Chinese mainland is a grand mosaic structure of many crust blocks bounded by faults and sutures. When it is suffered from boundary stresses, deformation takes place along these faults or sutures while the block interiors remain relatively stable or intact. Since the Quaternary, for example, left slip on the Xianshuihe-Xiaojiang fault zone in southwestern China has produced a number of fault-depression basins in extensional areas during periods Q1 and Q2. In the Q3, the change of stress orientation and enhancement of tectonic movement made faults of varied trends link each other, and continued to be active till present day, producing active fanlt zones in this region. Usually major earthquakes occur at some special locations on these active fault zones. During these events, in the epicenter areas experience intensive deformation character- ized by large-amplitude rise and fall of neighboring sections, generation of horst-graben systems and dammed rivers. The studies on palaeoearthquakes suggest that major shocks of close magnitudes often repeated for several times at a same place. By comparison of the Chi-Chi, Taiwan event in 1999 and Yuza, Yunnan event in 1955, including contours of accelerations and intensities, destruction of buildings, and in contrast to the Xigeda formation in southwestern China, a sandwich model is established to account for the mechanism of deformation caused by major earthquakes. This model consists of three layers, i.e. the two walls of a fault and the ruptured zone intercalated between them. This ruptured zone is just the loci where stress is built up and released, and serves as a channel for seismic waves.展开更多
In this paper,we focused on earthquakes with M S≥7.0 in the Chinese mainland from1900 to 2012,calculated the lunisolar tidal Coulomb failure stress on the seismic fault plane and got the tidal phase through Schuster&...In this paper,we focused on earthquakes with M S≥7.0 in the Chinese mainland from1900 to 2012,calculated the lunisolar tidal Coulomb failure stress on the seismic fault plane and got the tidal phase through Schuster's test,then quantitatively analyzed the correlation between strong earthquakes in the Chinese mainland and tidal Coulomb failure stress.Research shows that among 57 strong earthquakes with focal mechanism solutions,over 71.9%took place within the tidal loading phase,with the p-value of 3.83%,indicating that strong earthquakes with M S≥7.0 in Chinese mainland have a certain correlation with lunisolar tidal Coulomb failure stress.In the active period,the p-value is4.56%,75.5%of earthquakes occurred in the tidal loading phase zone,and 50%of earthquakes occurred in the quiescence period,indicating that strong earthquakes in the active period were obviously triggered with the tidal Coulomb failure stress loading.展开更多
Wavelets are a useful tool for analyzing the time-frequency of a non-stable series and are widely applied in many fields. The process of earthquake preparation and occurrence is a non-linear process. In the paper, the...Wavelets are a useful tool for analyzing the time-frequency of a non-stable series and are widely applied in many fields. The process of earthquake preparation and occurrence is a non-linear process. In the paper, the wavelet method is used to analyze the series of earthquake data for the time period from 1900 to 2003 in the west of the Chinese mainland and its adjacent area (WCMAA), and to obtain the characteristic information for different time scales. In the past 103 years, there were four primary periods of regional earthquake activity in the area with durations of 42, 22, 7 and 14 years, respectively and the intensity of earthquake activity changing with time. It doesn’t make sense to talk about active or quiet periods of earthquake activity unless it is based on a specific time scale. In addition, the tendency analysis of earthquake activity using the primary period of seismic activity and wavelet coefficients of varied time scales indicates that the earthquake activity in this region will be high in the forthcoming years.展开更多
Previous studies have shown that the active tectonic block boundaries in the Chinese mainland are the main belts and concentration areas of strong earthquakes occurring in the Chinese mainland.It is essential to carry...Previous studies have shown that the active tectonic block boundaries in the Chinese mainland are the main belts and concentration areas of strong earthquakes occurring in the Chinese mainland.It is essential to carry out follow-up analysis of strong earthquake risk of active tectonic block boundaries.In this paper,we carry out the analysis on the tendency of strong earthquakes along each active tectonic block boundary from three aspects respectively,including the evolutionary characteristics of the Load/Unload Response Ratio time series,the probability method based on the log-normal distribution function,and variation of b value.The estimation of strong earthquake criticality on each active tectonic block boundary is done based on the evolutionary characteristics of the Load/Unload Response Ratio time series,the cumulative probability and conditional probability,and the decrease of the b value.Finally,according to the results of analyses on the above three aspects,the potential strong earthquake areas in the forthcoming 5 years in the Chinese mainland are discussed.展开更多
A checking on seismic and tsunami hazard for coastal nuclear power plant (NPP) of Chinese continent has been made after Japanese Fukushima nuclear accident caused by earthquake tsunami. The results of the checking are...A checking on seismic and tsunami hazard for coastal nuclear power plant (NPP) of Chinese continent has been made after Japanese Fukushima nuclear accident caused by earthquake tsunami. The results of the checking are introduced briefly in this paper,including the evaluations of seismic and tsunami hazard in NPP siting period,checking results on seismic and tsunami hazard. Because Chinese coastal area belongs to the continental shelf and far from the boundary of plate collision,the tsunami hazard is not significant for coastal area of Chinese continent. However,the effect from tsunami still can't be excluded absolutely since calculated result of Manila trench tsunami source although the tsunami wave is lower than water level from storm surge. The research about earthquake tsunami will continue in future. The tsunami warning system and emergency program of NPP will be established based on principle of defense in depth in China.展开更多
The regulation of the National Significant Seismic Monitoring and Protection Regions(NSSMPR for short) is defined by the Law of the Peoples Republic of China on Protecting Against and Mitigating Earthquake Disasters.T...The regulation of the National Significant Seismic Monitoring and Protection Regions(NSSMPR for short) is defined by the Law of the Peoples Republic of China on Protecting Against and Mitigating Earthquake Disasters.The first stage of implementation of the regulation of NSSMPR in the Chinese mainland was finished from 1996 to 2005.The second stage is being carried on from 2006 to 2020.With the support of the National Social Science Foundation,this paper follows up and evaluates the implementation of the regulation of NSSMPR from 1996 to 2012 in the Chinese mainland.Based on analysis of earthquake examples and investigation data,we find that the effect of disaster mitigation is good,and on this basis,some suggestions are proposed to improve the regulation of NSSMPR.展开更多
Two types of changes in apparent resistivity (AR) have been linked to earthquake occurrences. This paper studies the changes and their causes, in detail with the ultimate purpose of developing and assessing a method o...Two types of changes in apparent resistivity (AR) have been linked to earthquake occurrences. This paper studies the changes and their causes, in detail with the ultimate purpose of developing and assessing a method of earthquake (EQ) prediction. The AR changes of the first type (CFT) are considered to be precursors related to earthquakes (EQs); these appear mostly in the medium-term period before EQs and in the short-term period preceding EQs. The changes of the second type (CST) are characterized by a turning anomaly of a long-trend AR variation or the drastically descending/ascending anomaly superimposed on such a variation; these appear synchronously in large areas, such as the Chinese mainland, and northern and northwestern China, ect. Their spatio-temporal clusters correspond well to high seismicities in the areas and distant great EQs around the Chinese mainland. Based on the behaviors of the two types of changes, the AR changes observed prior to the Ms8.0 Wenchuan EQ of 2008 are studied. The results show that in the medium-term period before the EQ, noticeable anomalies appeared synchronously at four stations around the Songpan-Ganzi active block, but only weak upward changes were observed in the short-term period preceding the EQ, which caused the prediction of the imminent EQ to fail.展开更多
39473 Pn travel times are inverted to tomographically image both lateral variation and anisotropy of uppermost mantle velocities beneath China continent. The result indicates that the overall average Pn velocity of up...39473 Pn travel times are inverted to tomographically image both lateral variation and anisotropy of uppermost mantle velocities beneath China continent. The result indicates that the overall average Pn velocity of uppermost mantle in the studied region is 8.0 km/s and the regional velocity fluctuation varies from ?0.30 km/s to +0.35 km/s. Pn velocities higher than 8.2 km/s are found in the regions surrounding Qingzang Plateau, such as Junggar Basin, Tarim Basin, Qaidam Basin and Sichun Basin. Pn velocities slightly lower than the average are found in western Sichuan and Yunnan, Shanxi Graben and Bohai Bay region. A Pn velocity as low as 7.8 km/s may exist in the region striding the boundary between Guangxi and Guangdong provinces. In general, Pn velocity in tectonically stable region like cratonic platform tends to be high, while that in tectonically active region tends to be low. The regions in compressive setting usually show higher Pn velocity, while extensional basins or grabens generally display lower one. Anisotropy of Pn velocity is seen in some regions. In the southeastern region of Qingzang Plateau the directions of fastest Pn velocity show a rotation pattern, which may be related to southeastward escape of the plateau material due to the collision and compression of Indian Plate to Asia along Himalaya arc. Notable anisotropy also exists around Bohai Bay region, likely indicating crustal extending and possible magma activity therein.展开更多
Butterworth band-pass filter has been applied to S-wave data recorded at 8 stations in China mainland, and S-wave splitting at different frequency bands is analyzed. The results show that the delay time and the fast p...Butterworth band-pass filter has been applied to S-wave data recorded at 8 stations in China mainland, and S-wave splitting at different frequency bands is analyzed. The results show that the delay time and the fast polarization directions of S-wave splitting depend upon the frequency bands. There is an absence of S-wave splitting at the station of Urumqi (WMQ) for the band of 0.1-0.2 Hz. With the frequency band broadening, the delay time of S-wave splitting decreases at the stations of Beijing (BJI), Enshi (ENH), Kunming (KMI) and Mudanjiang (MDJ); the fast polarization direction changes from westward to eastward at Enshi (ENH), and from eastward to westward at Hailaer (HIA). The variations of delay time with bands at Lanzhou (LZH) and Qiongzhong (QIZ) are similar, and there is a coherent trend of fast polarization directions at BJI, KMI and MDJ, respectively. Initial interpretations to the results of frequency band-dependence of S-wave splitting are also presented.展开更多
Accurately characterizing the threedimensional geometric contacts between the crust of the Chinese mainland and adjacent regions is important for understanding the dynamics of this part of Asia from the viewpoint of g...Accurately characterizing the threedimensional geometric contacts between the crust of the Chinese mainland and adjacent regions is important for understanding the dynamics of this part of Asia from the viewpoint of global plate systems. In this pa per, a method is introduced to investigate the geometric contacts between the Eurasian and Indian plates at the Burma arc sub duction zone using earthquake source parameters based on the Slabl.0 model of Hayes et al. (2009, 2010). The distribution of earthquake focus depths positioned in 166 sections along the Burma Arc subduction zone boundary has been investigated. Linear plane fitting and curved surface fitting has been performed on each section. Threedimensional geometric contacts and the extent of subduction are defined quantitatively. Finally, the focal depth distribution is outlined for six typical sections along the Burma arc subduction zone, combining focal mechanisms with background knowledge of geologic structure. Possible dy namic interaction patterns are presented and discussed. This paper provides an elementary method for studying the geometric contact of the Chinese mainland crust with adjacent plates and serves as a global reference for dynamic interactions between plates and related geodynamic investigations.展开更多
基金The Central Level,Scientific Research Institutes for Basic R & D Special Fund Business (No.2060302)National Natural Science Foundation of China(No.40841016,No.40372131 and No.40702056)Old Experts Science Foundation of China Earthquake Administration(No.201039)
文摘The paper presented a new regular pattern (network structure ) of great earthquakes occurred in China's Mainland during the past 700 years, which may be helpful to improve the understanding of great earthquakes and can serve as a base for the study of prediction of future great earthquakes. It can be done because there are quite complete and confident records of historical and recent earthquakes in a wide extent in China.
基金sponsored by the Youth Fund of National Natural Science Foundation of China(41302171)National Natural Science Foundation of China(41372345)
文摘We collect seismic moment tensors of the earthquakes occurring from 1900 to 2013 in and around the Chinese mainland and summarize the surface ruptures and displacements of 70 earthquakes with M S≥7. 0. We divide these large earthquakes into three types. Type A contains earthquakes with surface ruptures and displacements. Type B is earthquakes without displacements and Type C is those without any of this data. We simulate a triangular distribution of displacements for Type B and C. Then,we segment these large earthquakes by using their displacements and surface ruptures. Finally,kinematic models are determined from earthquake data and Bicubic Bessel spline functions. The results show that,first of all,the reasonability and spatial consistency of defined models are advanced.Strain rates have better continuity and are comparable with geologic and geodetic results in Himalaya thrust fault zones. The strain rates decrease in the Tarim basin and the Altun Tagh fault zones because of their low seismicity. The direction of compressional deformation in Gobi-Altay is changed from SE to NE and its extensional direction is changed from NE to NW. The extensional deformation in the Ordos block is diminished obviously. Secondly,earthquakes account for 30- 50% of expected motion of India relative to Eurasia determined from the NUVEL-1A model,with a missing component of 20 mm / a which may contain aseismic deformation such as fault creep and folds,the missing parts of earthquake data and elastic strain energy released by potential earthquakes.
文摘A major earthquake occurrence zone means a place where M ≥6 events have occurred since the Holocene and similar shocks may happen again in the future. The dynamic context of the major earthquake occurrence zones in China is primarily associated with the NNE-directed push of the India plate, next with the westward subduction of the Pacific plate. The Chinese mainland is a grand mosaic structure of many crust blocks bounded by faults and sutures. When it is suffered from boundary stresses, deformation takes place along these faults or sutures while the block interiors remain relatively stable or intact. Since the Quaternary, for example, left slip on the Xianshuihe-Xiaojiang fault zone in southwestern China has produced a number of fault-depression basins in extensional areas during periods Q1 and Q2. In the Q3, the change of stress orientation and enhancement of tectonic movement made faults of varied trends link each other, and continued to be active till present day, producing active fanlt zones in this region. Usually major earthquakes occur at some special locations on these active fault zones. During these events, in the epicenter areas experience intensive deformation character- ized by large-amplitude rise and fall of neighboring sections, generation of horst-graben systems and dammed rivers. The studies on palaeoearthquakes suggest that major shocks of close magnitudes often repeated for several times at a same place. By comparison of the Chi-Chi, Taiwan event in 1999 and Yuza, Yunnan event in 1955, including contours of accelerations and intensities, destruction of buildings, and in contrast to the Xigeda formation in southwestern China, a sandwich model is established to account for the mechanism of deformation caused by major earthquakes. This model consists of three layers, i.e. the two walls of a fault and the ruptured zone intercalated between them. This ruptured zone is just the loci where stress is built up and released, and serves as a channel for seismic waves.
基金supported by the Earthquake Science and Technology Development Fund of Lanzhou Institute of Seismology,CEA(2012M01)National Natural Science Foundation(41174059)China Earthquake Administration as a Work Assignment for Seismic Situation Tracing(2012020101)
文摘In this paper,we focused on earthquakes with M S≥7.0 in the Chinese mainland from1900 to 2012,calculated the lunisolar tidal Coulomb failure stress on the seismic fault plane and got the tidal phase through Schuster's test,then quantitatively analyzed the correlation between strong earthquakes in the Chinese mainland and tidal Coulomb failure stress.Research shows that among 57 strong earthquakes with focal mechanism solutions,over 71.9%took place within the tidal loading phase,with the p-value of 3.83%,indicating that strong earthquakes with M S≥7.0 in Chinese mainland have a certain correlation with lunisolar tidal Coulomb failure stress.In the active period,the p-value is4.56%,75.5%of earthquakes occurred in the tidal loading phase zone,and 50%of earthquakes occurred in the quiescence period,indicating that strong earthquakes in the active period were obviously triggered with the tidal Coulomb failure stress loading.
文摘Wavelets are a useful tool for analyzing the time-frequency of a non-stable series and are widely applied in many fields. The process of earthquake preparation and occurrence is a non-linear process. In the paper, the wavelet method is used to analyze the series of earthquake data for the time period from 1900 to 2003 in the west of the Chinese mainland and its adjacent area (WCMAA), and to obtain the characteristic information for different time scales. In the past 103 years, there were four primary periods of regional earthquake activity in the area with durations of 42, 22, 7 and 14 years, respectively and the intensity of earthquake activity changing with time. It doesn’t make sense to talk about active or quiet periods of earthquake activity unless it is based on a specific time scale. In addition, the tendency analysis of earthquake activity using the primary period of seismic activity and wavelet coefficients of varied time scales indicates that the earthquake activity in this region will be high in the forthcoming years.
基金sponsored by the Special Basic Scientific Research Program of Institute of Earthquake Science(02092425),China Earthquake Administration
文摘Previous studies have shown that the active tectonic block boundaries in the Chinese mainland are the main belts and concentration areas of strong earthquakes occurring in the Chinese mainland.It is essential to carry out follow-up analysis of strong earthquake risk of active tectonic block boundaries.In this paper,we carry out the analysis on the tendency of strong earthquakes along each active tectonic block boundary from three aspects respectively,including the evolutionary characteristics of the Load/Unload Response Ratio time series,the probability method based on the log-normal distribution function,and variation of b value.The estimation of strong earthquake criticality on each active tectonic block boundary is done based on the evolutionary characteristics of the Load/Unload Response Ratio time series,the cumulative probability and conditional probability,and the decrease of the b value.Finally,according to the results of analyses on the above three aspects,the potential strong earthquake areas in the forthcoming 5 years in the Chinese mainland are discussed.
文摘A checking on seismic and tsunami hazard for coastal nuclear power plant (NPP) of Chinese continent has been made after Japanese Fukushima nuclear accident caused by earthquake tsunami. The results of the checking are introduced briefly in this paper,including the evaluations of seismic and tsunami hazard in NPP siting period,checking results on seismic and tsunami hazard. Because Chinese coastal area belongs to the continental shelf and far from the boundary of plate collision,the tsunami hazard is not significant for coastal area of Chinese continent. However,the effect from tsunami still can't be excluded absolutely since calculated result of Manila trench tsunami source although the tsunami wave is lower than water level from storm surge. The research about earthquake tsunami will continue in future. The tsunami warning system and emergency program of NPP will be established based on principle of defense in depth in China.
基金sponsored by the National Social Science Foundation of China"Research on the Status,Efficiencies and the Policy on the National Significant Seismic Monitoring and Protection Regions"(11&ZD054)
文摘The regulation of the National Significant Seismic Monitoring and Protection Regions(NSSMPR for short) is defined by the Law of the Peoples Republic of China on Protecting Against and Mitigating Earthquake Disasters.The first stage of implementation of the regulation of NSSMPR in the Chinese mainland was finished from 1996 to 2005.The second stage is being carried on from 2006 to 2020.With the support of the National Social Science Foundation,this paper follows up and evaluates the implementation of the regulation of NSSMPR from 1996 to 2012 in the Chinese mainland.Based on analysis of earthquake examples and investigation data,we find that the effect of disaster mitigation is good,and on this basis,some suggestions are proposed to improve the regulation of NSSMPR.
基金supported by National Key Technology Research and Development Program of China (Grant Nos. 2008BAC35B01-8 and 2006BAC01B02-04-03)
文摘Two types of changes in apparent resistivity (AR) have been linked to earthquake occurrences. This paper studies the changes and their causes, in detail with the ultimate purpose of developing and assessing a method of earthquake (EQ) prediction. The AR changes of the first type (CFT) are considered to be precursors related to earthquakes (EQs); these appear mostly in the medium-term period before EQs and in the short-term period preceding EQs. The changes of the second type (CST) are characterized by a turning anomaly of a long-trend AR variation or the drastically descending/ascending anomaly superimposed on such a variation; these appear synchronously in large areas, such as the Chinese mainland, and northern and northwestern China, ect. Their spatio-temporal clusters correspond well to high seismicities in the areas and distant great EQs around the Chinese mainland. Based on the behaviors of the two types of changes, the AR changes observed prior to the Ms8.0 Wenchuan EQ of 2008 are studied. The results show that in the medium-term period before the EQ, noticeable anomalies appeared synchronously at four stations around the Songpan-Ganzi active block, but only weak upward changes were observed in the short-term period preceding the EQ, which caused the prediction of the imminent EQ to fail.
基金This work was supported by the National Key Basic Research Project (Grant No. G1998040700)and partly by US National Science Foundation grant (EAR9614616). Contribution No. 01FE2013, Institute of Geophysics, China Seismological Bureau. We sincerely than
文摘39473 Pn travel times are inverted to tomographically image both lateral variation and anisotropy of uppermost mantle velocities beneath China continent. The result indicates that the overall average Pn velocity of uppermost mantle in the studied region is 8.0 km/s and the regional velocity fluctuation varies from ?0.30 km/s to +0.35 km/s. Pn velocities higher than 8.2 km/s are found in the regions surrounding Qingzang Plateau, such as Junggar Basin, Tarim Basin, Qaidam Basin and Sichun Basin. Pn velocities slightly lower than the average are found in western Sichuan and Yunnan, Shanxi Graben and Bohai Bay region. A Pn velocity as low as 7.8 km/s may exist in the region striding the boundary between Guangxi and Guangdong provinces. In general, Pn velocity in tectonically stable region like cratonic platform tends to be high, while that in tectonically active region tends to be low. The regions in compressive setting usually show higher Pn velocity, while extensional basins or grabens generally display lower one. Anisotropy of Pn velocity is seen in some regions. In the southeastern region of Qingzang Plateau the directions of fastest Pn velocity show a rotation pattern, which may be related to southeastward escape of the plateau material due to the collision and compression of Indian Plate to Asia along Himalaya arc. Notable anisotropy also exists around Bohai Bay region, likely indicating crustal extending and possible magma activity therein.
基金the National Natural Science Foundation of China (NSFC) (Grant No. 49774225), and the Outstanding Youth Scientist Project from NSFC (Grant No. 49825108).
文摘Butterworth band-pass filter has been applied to S-wave data recorded at 8 stations in China mainland, and S-wave splitting at different frequency bands is analyzed. The results show that the delay time and the fast polarization directions of S-wave splitting depend upon the frequency bands. There is an absence of S-wave splitting at the station of Urumqi (WMQ) for the band of 0.1-0.2 Hz. With the frequency band broadening, the delay time of S-wave splitting decreases at the stations of Beijing (BJI), Enshi (ENH), Kunming (KMI) and Mudanjiang (MDJ); the fast polarization direction changes from westward to eastward at Enshi (ENH), and from eastward to westward at Hailaer (HIA). The variations of delay time with bands at Lanzhou (LZH) and Qiongzhong (QIZ) are similar, and there is a coherent trend of fast polarization directions at BJI, KMI and MDJ, respectively. Initial interpretations to the results of frequency band-dependence of S-wave splitting are also presented.
基金supported by the National Science and Technology Support Plan Project (Grant No.2012BAK19B01-04)
文摘Accurately characterizing the threedimensional geometric contacts between the crust of the Chinese mainland and adjacent regions is important for understanding the dynamics of this part of Asia from the viewpoint of global plate systems. In this pa per, a method is introduced to investigate the geometric contacts between the Eurasian and Indian plates at the Burma arc sub duction zone using earthquake source parameters based on the Slabl.0 model of Hayes et al. (2009, 2010). The distribution of earthquake focus depths positioned in 166 sections along the Burma Arc subduction zone boundary has been investigated. Linear plane fitting and curved surface fitting has been performed on each section. Threedimensional geometric contacts and the extent of subduction are defined quantitatively. Finally, the focal depth distribution is outlined for six typical sections along the Burma arc subduction zone, combining focal mechanisms with background knowledge of geologic structure. Possible dy namic interaction patterns are presented and discussed. This paper provides an elementary method for studying the geometric contact of the Chinese mainland crust with adjacent plates and serves as a global reference for dynamic interactions between plates and related geodynamic investigations.