An earthquake of Ms=7.4 occurred in Mani, Xizang (Tibet), China on November 8, 1997. The moment tensor ofthis earthquake was inverted using the long period body wave form data from China Digital Seismograph Network(CD...An earthquake of Ms=7.4 occurred in Mani, Xizang (Tibet), China on November 8, 1997. The moment tensor ofthis earthquake was inverted using the long period body wave form data from China Digital Seismograph Network(CDSN). The apparent source time functions (AS TFs) were retrieved from P and S waves, respectively, using thedeconvolution technique in frequency domain, and the tempo-spatial rupture process on the fault plane was imagedby inverting the azimuth dependent AS TFs from different stations. The result of the moment tensor inversionindicates that the P and T axes of earthquake-generating stress field were nearly horizontal, with the P axis in theNNE direction (29), the T axis in the SEE direction (122) and that the NEE-SWW striking nodal plane andNNW-SSE striking nodal plane are mainly left-lateral and right-lateral strike-slip, respectively; that this earthquakehad a scalar seismic moment of 3.4xl02o N. .m, and a moment magnitude of Mw=7.6. Taking the aftershock distribution into account, we proposed that the earthquake rupture occurred in the fault plane with the strike of 250,the dip of 88 and the rake of 19. On the basis of the result of the moment tensor inversion, the theoretical seismograms were synthesized, and then the AS T Fs were retrieved by deconvoving the synthetic seismograms fromthe observed seismograms. The A S T Fs retrieved from the P and S waves of different stations identically suggestedthat this earthquake was of a simple time history, whose ASTF can be approximated with a sine function with thehalf period of about 10 s. Inverting the azimuth dependent A S T Fs from P and S waveforms led to the imageshowing the tempo-spatial distribution of the rupture on the fault plane. From the 'remembering' snap-shots, therupture initiated at the western end of the fault, and then propagated eastward and downward, indicating an overallunilateral rupture. However, the slip distribution is non-uniform, being made up of three sub-areas, one in thewestern end, about 10 km deep ('western area'), another about 55 kin away from the western end and about 35 Iondeep ('eastern area'), the third about 30 km away from the western end and around 40 km deep ('central area').The total rupture area was around 70 km long and 60 km wide. From the 'forgetting' snap-shots, the rupturingappeared quite complex, with the slip occurring in different position at different time, and the earthquake being ofthe characteristics of 'healing pulse'. Another point we have to stress is that the locations in which the ruptureinitiated and terminated were not where the main rupture took place. Eventually, the static slip distribution wascalculated, and the largest slip values of the three sub-areas were 956 cm, 743 cm and 1 060 cm, for the western.eastern and central areas, respectively. From the slip distribution, the rupture mainly distributed in the fault about70 km eastern to the epicenter; from the aftershock distribution. however, the aftershocks were very sparse in thewest to the epicenter while densely clustered in the east to the epicenter It indicated that the Maul Ms=7.9 earthquake was resulted from the nearly eastward extension of the NEE-SWW to nearly E-W striking fault in thenorthwestern Tibetan plateau.展开更多
By using the D-InSAR technique, we have acquired the temporal-spatial evolution images of preseismic.cosesimci-postseismic interferometric deformation fields associated with the M 7.9 earthquake of Mani, Tibet on 8 No...By using the D-InSAR technique, we have acquired the temporal-spatial evolution images of preseismic.cosesimci-postseismic interferometric deformation fields associated with the M 7.9 earthquake of Mani, Tibet on 8 November 1997. The analysis of these images reveals the relationships between the temporal-spatial evolution features of the interferometric deformation fields and locking, rupturing, and elastic restoring of the source rupture plane, which represent the processes of strain accumulation, strain release, and postseismic restoration. The result shows that 10 months prior to the Mani event, a left-lateral shear trend appeared in the seismic area, which was in accordance with the earthquake fault in nature. The quantity of local deformation on the north wall was slightly larger than that on the south wall, and the deformation distribution area of the north wall was relatively large. With the event impending, the deformation of the south wall varied increasingly, and the deformation center shifted eastward. Two and half monthd before the event, the west side of the fault was still locked while the east side began to slide, implying that the whole fault would rupture at any moment. These features can be regarded as short-term precursors to this earthquake. Within the period from 16 April 1996 to two and half months before the earthquake, the most remarkable deformation zones appeared in the north and south walls, which were parallel to and about 40 km apart from the fault, with accumulated local displacements of 344 mm and 251 mm on the north and south walls, respectively. The south wall was the active one with larger displacements. Five months after the earthquake, the distribution feature of interferometric fringes was just opposite to that prior to the event, expressing evident right-lateral shear. The recovered displacements are -179 mm on the north wall and -79 mm on the south wall, close to the east side of the fault. However, in the area of the south wall far from the fault there still existed a trend of sinistral motion. The deformation of the north wall was small but recovered fast in a larger area, while the active south wall began to recover from the east section of the fault toward the WSW.展开更多
Breakthrough point source model, extended earthquake source model is used to calculate more seismic source parameters in this paper. We express seismic source using higher degree moment tensors, to reduce a Iarge numb...Breakthrough point source model, extended earthquake source model is used to calculate more seismic source parameters in this paper. We express seismic source using higher degree moment tensors, to reduce a Iarge number terms originally presenting in higher degree moment tensor representation, Haskell rupture model is used. We in verted the source parameters of Mani earthquake in Tibet using broad-band body wave of 32 stations of Global Seismograph Network (GSN), the results show that it is a strike-slip fault, rupture direction is 75°, rupture duration is 19 s, the fault plan is φ=77°， δ5=88°, A=0°, the auxiliare plane is φ=347°, δ=90°, k=178°, and the fault dimension is 47 km×28 km. These results will give new quantitative data for earth dynamics and have practical meaning for seismic source tomography research.展开更多
DEAR EDITOR,The key features of functional extinction include continuous reproductive failure,lack of new recruitment,and persistent population decline(Jarićet al.,2016;Roberts et al.,2017).However,the conclusion of f...DEAR EDITOR,The key features of functional extinction include continuous reproductive failure,lack of new recruitment,and persistent population decline(Jarićet al.,2016;Roberts et al.,2017).However,the conclusion of functional extinction for the Chinese pangolin(Manis pentadactyla)by the China Biodiversity Conservation and Green Development Foundation(CBC-GDF)based on preliminary field information is unconvincing as they did not assess reproductive function or new individual recruitment of Chinese pangolin populations(Supplementary Materials).展开更多
In this paper, we give a local Hamilton＇s gradient estimate for a nonlinear parabol- ic equation on Riemannian manifolds. As its application, a Harnack-type inequality and a Liouville-type theorem are obtained.
Origin of ancient Indian toxicology can be dated back to vedic literature.Toxins of both animate and inanimate world were very well understood during the era.Rig and Atharva vedic texts describe such details.After cla...Origin of ancient Indian toxicology can be dated back to vedic literature.Toxins of both animate and inanimate world were very well understood during the era.Rig and Atharva vedic texts describe such details.After classifying such toxins,Charaka Samhitha,thebasic literature of Indian Medicine used gold and ghee as panaceas to counter act them.Ayurveda considers toxicology as one among the eight specialized branches of medical wisdom.Unfortunately,the available literature on this is very limited.Moreover,they have been discussed briefly in Charaka and Sushrutha Samhitha.Mangarasa I,a Jain scholar who lived on the foothills of the Western Ghats,in Southern India in 1350 A.D.,felt this vacuum and composed an independent,elaborate Kannada text on toxicology.His less known text Khagendra Mani Darpana(KMD)is the first ever documented complete text on toxicology in the world.Medieval Indian wisdom on plant and animal diversities are very well reflected in this unique toxicological text.Centuries past to Linnean era,KMD gives vivid descriptions on zoological and botanical diversities of the time.This astonishing fact is an evidence of our ancestor's curiosities about the nature around them.A critical overview of the bio-diversity described in KMD text is discussed in this paper.展开更多
Interferometry Synthetic Aperture Radar (InSAR) is a kind of new earth observation technique and great development has been made in the recent ten years. In the paper, InSAR and Differential Interferometric Synthetic ...Interferometry Synthetic Aperture Radar (InSAR) is a kind of new earth observation technique and great development has been made in the recent ten years. In the paper, InSAR and Differential Interferometric Synthetic Aperture Radar (D-InSAR) are generally introduced; then the factors affecting the data accuracy are primarily discussed. The 1997 Mani earthquake was selected as an example to obtain the coseismic deformation field with the three-pass differential interferometric processing method. The results show that the coseismic deformation field is about 200 km in length and 115 km in width. The interferometric fringes spread in the area with the NEE-trending seismogenic fault the Margaichaka fault as the center and they are primarily parallel to the fault. Based on the analysis to the interferogram, the seismogenic fault can be divided into three segments. The whole fault is about 110 km and the length of each segment from the west to the east is about 23 km, 60 km and 26 km. The maximum uplifting displacement in the side-looking direction near the seismic center is about 162.4 cm, the maximum subsiding displacement in the side-looking direction in the western part of the fault is about 103.6 cm, and the maximum horizontal surface dislocation near the seismic center is about 7.96 m.展开更多
Chinese pangolin(Manis pentadactyla) has important value in Chinese medicine,economy and ecology.At present,Chinese pangolin is about to go extinct due to over hunting and habitat destruction,which has caused a dramat...Chinese pangolin(Manis pentadactyla) has important value in Chinese medicine,economy and ecology.At present,Chinese pangolin is about to go extinct due to over hunting and habitat destruction,which has caused a dramatic decline in the wild population.Breeding Chinese pangolin in captivity is very difficult and has not succeeded yet.This paper is to review the wild population,habitat,foraging,activity rhythm,breeding and physiology of Chinese pangolin.It provides theoretical basis of ecology and biology for the protection and artificial domestication of Chinese pangolin.Meanwhile,given the demands of protection,future research directions are suggested.展开更多
We obtain the co-seismic ground deformation field of the Mani M7.9 earthquake on November 8, 1997 through three-pass differential interferometric processing. Then we get the geometric and kinematics parameters of this...We obtain the co-seismic ground deformation field of the Mani M7.9 earthquake on November 8, 1997 through three-pass differential interferometric processing. Then we get the geometric and kinematics parameters of this event by the elastic half-space model and forward modeling with the InSAR data. The following results have been obtained: (i) The deformation fields on both sides of the seismogenic fault are affected by the co-seismic deformation field even in 110 km away from the fault. The loss of phase coherence belt caused by the zone of ground rupture crosses the image from east to west with a length of an area 110 km. (ii) The maximum horizontal displacement caused by the earthquake reaches 7.96 m. (iii) The earthquake fault can be divided into four parts, and the deformation field of the middle two parts is bigger than that of the other two, with lengths of 27 km and 37 km, respectively. And their average sliding values on the rupture surface are 6500 mm and 6000 mm, respectively, and their depths both are 35 km. The segment of 27 km length is the major rupture surface of this earthquake. The west part and the east part of the fault have lengths of 23 km and 26 km, respectively. The sliding value of the west one is 4000 mm and that of the east one is 5800 mm. They extend to depths of 20 km and 18 km, respectively.展开更多
文摘An earthquake of Ms=7.4 occurred in Mani, Xizang (Tibet), China on November 8, 1997. The moment tensor ofthis earthquake was inverted using the long period body wave form data from China Digital Seismograph Network(CDSN). The apparent source time functions (AS TFs) were retrieved from P and S waves, respectively, using thedeconvolution technique in frequency domain, and the tempo-spatial rupture process on the fault plane was imagedby inverting the azimuth dependent AS TFs from different stations. The result of the moment tensor inversionindicates that the P and T axes of earthquake-generating stress field were nearly horizontal, with the P axis in theNNE direction (29), the T axis in the SEE direction (122) and that the NEE-SWW striking nodal plane andNNW-SSE striking nodal plane are mainly left-lateral and right-lateral strike-slip, respectively; that this earthquakehad a scalar seismic moment of 3.4xl02o N. .m, and a moment magnitude of Mw=7.6. Taking the aftershock distribution into account, we proposed that the earthquake rupture occurred in the fault plane with the strike of 250,the dip of 88 and the rake of 19. On the basis of the result of the moment tensor inversion, the theoretical seismograms were synthesized, and then the AS T Fs were retrieved by deconvoving the synthetic seismograms fromthe observed seismograms. The A S T Fs retrieved from the P and S waves of different stations identically suggestedthat this earthquake was of a simple time history, whose ASTF can be approximated with a sine function with thehalf period of about 10 s. Inverting the azimuth dependent A S T Fs from P and S waveforms led to the imageshowing the tempo-spatial distribution of the rupture on the fault plane. From the 'remembering' snap-shots, therupture initiated at the western end of the fault, and then propagated eastward and downward, indicating an overallunilateral rupture. However, the slip distribution is non-uniform, being made up of three sub-areas, one in thewestern end, about 10 km deep ('western area'), another about 55 kin away from the western end and about 35 Iondeep ('eastern area'), the third about 30 km away from the western end and around 40 km deep ('central area').The total rupture area was around 70 km long and 60 km wide. From the 'forgetting' snap-shots, the rupturingappeared quite complex, with the slip occurring in different position at different time, and the earthquake being ofthe characteristics of 'healing pulse'. Another point we have to stress is that the locations in which the ruptureinitiated and terminated were not where the main rupture took place. Eventually, the static slip distribution wascalculated, and the largest slip values of the three sub-areas were 956 cm, 743 cm and 1 060 cm, for the western.eastern and central areas, respectively. From the slip distribution, the rupture mainly distributed in the fault about70 km eastern to the epicenter; from the aftershock distribution. however, the aftershocks were very sparse in thewest to the epicenter while densely clustered in the east to the epicenter It indicated that the Maul Ms=7.9 earthquake was resulted from the nearly eastward extension of the NEE-SWW to nearly E-W striking fault in thenorthwestern Tibetan plateau.
基金This work was supported by the National Natural Science Foundation of China （grants 40574007 and 40374013）he radar data used are partially offered by the project ENVISAT A0-711 of Europe Space Administration.
文摘By using the D-InSAR technique, we have acquired the temporal-spatial evolution images of preseismic.cosesimci-postseismic interferometric deformation fields associated with the M 7.9 earthquake of Mani, Tibet on 8 November 1997. The analysis of these images reveals the relationships between the temporal-spatial evolution features of the interferometric deformation fields and locking, rupturing, and elastic restoring of the source rupture plane, which represent the processes of strain accumulation, strain release, and postseismic restoration. The result shows that 10 months prior to the Mani event, a left-lateral shear trend appeared in the seismic area, which was in accordance with the earthquake fault in nature. The quantity of local deformation on the north wall was slightly larger than that on the south wall, and the deformation distribution area of the north wall was relatively large. With the event impending, the deformation of the south wall varied increasingly, and the deformation center shifted eastward. Two and half monthd before the event, the west side of the fault was still locked while the east side began to slide, implying that the whole fault would rupture at any moment. These features can be regarded as short-term precursors to this earthquake. Within the period from 16 April 1996 to two and half months before the earthquake, the most remarkable deformation zones appeared in the north and south walls, which were parallel to and about 40 km apart from the fault, with accumulated local displacements of 344 mm and 251 mm on the north and south walls, respectively. The south wall was the active one with larger displacements. Five months after the earthquake, the distribution feature of interferometric fringes was just opposite to that prior to the event, expressing evident right-lateral shear. The recovered displacements are -179 mm on the north wall and -79 mm on the south wall, close to the east side of the fault. However, in the area of the south wall far from the fault there still existed a trend of sinistral motion. The deformation of the north wall was small but recovered fast in a larger area, while the active south wall began to recover from the east section of the fault toward the WSW.
文摘Breakthrough point source model, extended earthquake source model is used to calculate more seismic source parameters in this paper. We express seismic source using higher degree moment tensors, to reduce a Iarge number terms originally presenting in higher degree moment tensor representation, Haskell rupture model is used. We in verted the source parameters of Mani earthquake in Tibet using broad-band body wave of 32 stations of Global Seismograph Network (GSN), the results show that it is a strike-slip fault, rupture direction is 75°, rupture duration is 19 s, the fault plan is φ=77°， δ5=88°, A=0°, the auxiliare plane is φ=347°, δ=90°, k=178°, and the fault dimension is 47 km×28 km. These results will give new quantitative data for earth dynamics and have practical meaning for seismic source tomography research.
基金supported by the National Key Program of Research and Development,Ministry of Science and Technology(2022YFF1301500)National Nature Science Foundation of China(32070522,31572286)+1 种基金China State Forestry and Grassland Administration(2018-HS01)the Ministry of Ecology and Environment of the People’s Republic of China(2019-6-2)。
文摘DEAR EDITOR,The key features of functional extinction include continuous reproductive failure,lack of new recruitment,and persistent population decline(Jarićet al.,2016;Roberts et al.,2017).However,the conclusion of functional extinction for the Chinese pangolin(Manis pentadactyla)by the China Biodiversity Conservation and Green Development Foundation(CBC-GDF)based on preliminary field information is unconvincing as they did not assess reproductive function or new individual recruitment of Chinese pangolin populations(Supplementary Materials).
基金Supported by the National Natural Science Foundation of China(Grant Nos.1126103811271132)the Jiangxi Normal University Youth Development Fund
文摘In this paper, we give a local Hamilton＇s gradient estimate for a nonlinear parabol- ic equation on Riemannian manifolds. As its application, a Harnack-type inequality and a Liouville-type theorem are obtained.
基金Supported by Indian National Science Academy(under Ministry of Science and Technology Govt.of India)HS/RC/NC/700 dated 22.6.2009
文摘Origin of ancient Indian toxicology can be dated back to vedic literature.Toxins of both animate and inanimate world were very well understood during the era.Rig and Atharva vedic texts describe such details.After classifying such toxins,Charaka Samhitha,thebasic literature of Indian Medicine used gold and ghee as panaceas to counter act them.Ayurveda considers toxicology as one among the eight specialized branches of medical wisdom.Unfortunately,the available literature on this is very limited.Moreover,they have been discussed briefly in Charaka and Sushrutha Samhitha.Mangarasa I,a Jain scholar who lived on the foothills of the Western Ghats,in Southern India in 1350 A.D.,felt this vacuum and composed an independent,elaborate Kannada text on toxicology.His less known text Khagendra Mani Darpana(KMD)is the first ever documented complete text on toxicology in the world.Medieval Indian wisdom on plant and animal diversities are very well reflected in this unique toxicological text.Centuries past to Linnean era,KMD gives vivid descriptions on zoological and botanical diversities of the time.This astonishing fact is an evidence of our ancestor's curiosities about the nature around them.A critical overview of the bio-diversity described in KMD text is discussed in this paper.
基金Joint Seismological Science Foundation of China (102096) and State Natural Scientific Foundation of China (40142031 49802027) and State Key Basic Research Development and Programming Project (G1998040703).
文摘Interferometry Synthetic Aperture Radar (InSAR) is a kind of new earth observation technique and great development has been made in the recent ten years. In the paper, InSAR and Differential Interferometric Synthetic Aperture Radar (D-InSAR) are generally introduced; then the factors affecting the data accuracy are primarily discussed. The 1997 Mani earthquake was selected as an example to obtain the coseismic deformation field with the three-pass differential interferometric processing method. The results show that the coseismic deformation field is about 200 km in length and 115 km in width. The interferometric fringes spread in the area with the NEE-trending seismogenic fault the Margaichaka fault as the center and they are primarily parallel to the fault. Based on the analysis to the interferogram, the seismogenic fault can be divided into three segments. The whole fault is about 110 km and the length of each segment from the west to the east is about 23 km, 60 km and 26 km. The maximum uplifting displacement in the side-looking direction near the seismic center is about 162.4 cm, the maximum subsiding displacement in the side-looking direction in the western part of the fault is about 103.6 cm, and the maximum horizontal surface dislocation near the seismic center is about 7.96 m.
基金Supported by National Natural Science Foundation of China(31470570)Chongqing Natural Science Foundation(cstc2014jcyj A80013)+1 种基金Science Foundation of Chongqing Education Commission(kj1400534)Chongqing Creative Program for Graduate Students(CYS15155)
文摘Chinese pangolin(Manis pentadactyla) has important value in Chinese medicine,economy and ecology.At present,Chinese pangolin is about to go extinct due to over hunting and habitat destruction,which has caused a dramatic decline in the wild population.Breeding Chinese pangolin in captivity is very difficult and has not succeeded yet.This paper is to review the wild population,habitat,foraging,activity rhythm,breeding and physiology of Chinese pangolin.It provides theoretical basis of ecology and biology for the protection and artificial domestication of Chinese pangolin.Meanwhile,given the demands of protection,future research directions are suggested.
基金This work was supported by the National Key Basic Research Program (Grant No. G1998040703) the National Natural Science Foundation of China (Grant Nos.49989001,49802027) Some of SAR data were provided by ESA for the ENVISAT Project (A0-711).
文摘We obtain the co-seismic ground deformation field of the Mani M7.9 earthquake on November 8, 1997 through three-pass differential interferometric processing. Then we get the geometric and kinematics parameters of this event by the elastic half-space model and forward modeling with the InSAR data. The following results have been obtained: (i) The deformation fields on both sides of the seismogenic fault are affected by the co-seismic deformation field even in 110 km away from the fault. The loss of phase coherence belt caused by the zone of ground rupture crosses the image from east to west with a length of an area 110 km. (ii) The maximum horizontal displacement caused by the earthquake reaches 7.96 m. (iii) The earthquake fault can be divided into four parts, and the deformation field of the middle two parts is bigger than that of the other two, with lengths of 27 km and 37 km, respectively. And their average sliding values on the rupture surface are 6500 mm and 6000 mm, respectively, and their depths both are 35 km. The segment of 27 km length is the major rupture surface of this earthquake. The west part and the east part of the fault have lengths of 23 km and 26 km, respectively. The sliding value of the west one is 4000 mm and that of the east one is 5800 mm. They extend to depths of 20 km and 18 km, respectively.
