{"title":"Editorial Committee of Chinese Journal of Geophysics","authors":"","doi":"10.3724/sp.j.7102632840","DOIUrl":"https://doi.org/10.3724/sp.j.7102632840","url":null,"abstract":"","PeriodicalId":55257,"journal":{"name":"地球物理学报","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49522314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The amplitude or attenuation of casing waves is used to evaluate cement bonding quality in cased wells.At the 70~500 kHz frequency range,the casing waves generated by the acoustic tools are similar to the fundamental symmetric Lamb waves or anti-symmetric Lamb waves in acoustic terminology.The fundamental symmetric Lamb waves are called extensional waves and the fundamental anti-symmetric Lamb waves are called flexural Lamb waves.The two kinds of quasi-Lamb models show different propagation characteristics.The viscoelastic slip theory is applied to reveal the motion characteristics of extensional waves and flexural Lamb waves.The extensional wave propagating in the casing couples with the medium behind casing by shear stiffness.The existence of 0.01 mm micro annulus can cause sharp decrease of the extensional wave attenuation.By contrary,flexural Lamb-wave attenuation is not sensitive to micro annulus with lightweight cement behind the casing.The response characteristic of the flexural Lamb-wave attenuation with heavy cement behind casing is different from that with lightweight cement behind casing.The attenuation of the flexural waves shows evident increase with micro annulus existence.So the flexural Lamb-waves couple with the medium behind casing mainly by normal stiffness.With fluid micro annulus between casing and cement,the equivalent impedance of the media behind casing is less than that of heavy cement.The lower impedance can be prone to normal deformation and acoustic coupling between casing and the medium behind casing.The different response characteristics of extensional waves and flexural Lamb waves in cased wells provide possibility to determine the cementing situation in the comprehensive evaluation of cement bonding quality.
{"title":"Study on the propagation characteristics of the casing waves in cased wells by viscoelastic slip theory","authors":"陈雪莲, 唐晓明, 李盛清, 李疾翎, 江灿, 刘临政","doi":"10.6038/CJG2020N0050","DOIUrl":"https://doi.org/10.6038/CJG2020N0050","url":null,"abstract":"The amplitude or attenuation of casing waves is used to evaluate cement bonding quality in cased wells.At the 70~500 kHz frequency range,the casing waves generated by the acoustic tools are similar to the fundamental symmetric Lamb waves or anti-symmetric Lamb waves in acoustic terminology.The fundamental symmetric Lamb waves are called extensional waves and the fundamental anti-symmetric Lamb waves are called flexural Lamb waves.The two kinds of quasi-Lamb models show different propagation characteristics.The viscoelastic slip theory is applied to reveal the motion characteristics of extensional waves and flexural Lamb waves.The extensional wave propagating in the casing couples with the medium behind casing by shear stiffness.The existence of 0.01 mm micro annulus can cause sharp decrease of the extensional wave attenuation.By contrary,flexural Lamb-wave attenuation is not sensitive to micro annulus with lightweight cement behind the casing.The response characteristic of the flexural Lamb-wave attenuation with heavy cement behind casing is different from that with lightweight cement behind casing.The attenuation of the flexural waves shows evident increase with micro annulus existence.So the flexural Lamb-waves couple with the medium behind casing mainly by normal stiffness.With fluid micro annulus between casing and cement,the equivalent impedance of the media behind casing is less than that of heavy cement.The lower impedance can be prone to normal deformation and acoustic coupling between casing and the medium behind casing.The different response characteristics of extensional waves and flexural Lamb waves in cased wells provide possibility to determine the cementing situation in the comprehensive evaluation of cement bonding quality.","PeriodicalId":55257,"journal":{"name":"地球物理学报","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44840582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Editorial Committee of Chinese Journal of Geophysics","authors":"","doi":"10.3724/sp.j.7102081289","DOIUrl":"https://doi.org/10.3724/sp.j.7102081289","url":null,"abstract":"","PeriodicalId":55257,"journal":{"name":"地球物理学报","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45721670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Editorial Committee of Chinese Journal of Geophysics","authors":"","doi":"10.3724/sp.j.7101788840","DOIUrl":"https://doi.org/10.3724/sp.j.7101788840","url":null,"abstract":"","PeriodicalId":55257,"journal":{"name":"地球物理学报","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46410160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Editorial Committee of Chinese Journal of Geophysics","authors":"","doi":"10.3724/sp.j.7101470010","DOIUrl":"https://doi.org/10.3724/sp.j.7101470010","url":null,"abstract":"","PeriodicalId":55257,"journal":{"name":"地球物理学报","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45001234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Editorial Committee of Chinese Journal of Geophysics","authors":"","doi":"10.3724/sp.j.7101015758","DOIUrl":"https://doi.org/10.3724/sp.j.7101015758","url":null,"abstract":"","PeriodicalId":55257,"journal":{"name":"地球物理学报","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2020-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47081093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
null Lin XiangDong, null Yuan HuaiYu, N. Wen, null Yang Xuan, null Mu LeiYu, null Zhao GuiRu, null Sun HaiXia, null Hou LiJuan, null Wu MinJie, null Dong FeiFei
{"title":"Characteristics of seismic phase Pb and the Conrad interface beneath the Capital Circle region around Beijing","authors":"null Lin XiangDong, null Yuan HuaiYu, N. Wen, null Yang Xuan, null Mu LeiYu, null Zhao GuiRu, null Sun HaiXia, null Hou LiJuan, null Wu MinJie, null Dong FeiFei","doi":"10.6038/CJG2019M0261","DOIUrl":"https://doi.org/10.6038/CJG2019M0261","url":null,"abstract":"","PeriodicalId":55257,"journal":{"name":"地球物理学报","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43677473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Q. Yao, Xi-wei Xu, H. Xing, Jia Cheng, Guoyan Jiang, Weiyu Ma, Jie Liu, Wen Yang
On April 25th, 2015, the moment magnitude (M-w) 7. 8 Gorkha earthquake, Nepal occurred in Himalaya orogenic belt, which seems insufficient to release the accumulated energy as suggested previously. The following seismic risk assessments are mostly based on the two dimensional or pseudo-three dimensional inversions of tectonic deformation. Here we analyze the relationship between the main shock and biggest aftershock of the 2015 Gorkha earthquake sequence, and its unevenness in time and space. Combining focal mechanism solutions, crustal velocity structure, relocated aftershocks, and inversion results from InSAR, we construct a three dimensional model which changes along both the strike and dip directions of the Main Himalayan Thrust. The finite element method with nonlinear friction is used to calculate the fault behavior and block deformation in one earthquake recurrence period. Comparison between the forward calculation results and the co-seismic deformation observed from InSAR, and co-seismic slip inverted from deformation observations, and time-space evolution of historical earthquakes revealed that the three dimension model is close to the reality. The results suggest two potential seismic risk regions in the future: a big earthquake might be located in the east of the 1934 Bihar-Nepal M-w similar to 8. 1 earthquake, and a moderate to major event might take place to the southeast of the aftershock M(w)7. 3 earthquake.
{"title":"3D seismogenic model of the 2015 Gorkha earthquake and subsequent seismic risk","authors":"Q. Yao, Xi-wei Xu, H. Xing, Jia Cheng, Guoyan Jiang, Weiyu Ma, Jie Liu, Wen Yang","doi":"10.6038/CJG2018L0371","DOIUrl":"https://doi.org/10.6038/CJG2018L0371","url":null,"abstract":"On April 25th, 2015, the moment magnitude (M-w) 7. 8 Gorkha earthquake, Nepal occurred in Himalaya orogenic belt, which seems insufficient to release the accumulated energy as suggested previously. The following seismic risk assessments are mostly based on the two dimensional or pseudo-three dimensional inversions of tectonic deformation. Here we analyze the relationship between the main shock and biggest aftershock of the 2015 Gorkha earthquake sequence, and its unevenness in time and space. Combining focal mechanism solutions, crustal velocity structure, relocated aftershocks, and inversion results from InSAR, we construct a three dimensional model which changes along both the strike and dip directions of the Main Himalayan Thrust. The finite element method with nonlinear friction is used to calculate the fault behavior and block deformation in one earthquake recurrence period. Comparison between the forward calculation results and the co-seismic deformation observed from InSAR, and co-seismic slip inverted from deformation observations, and time-space evolution of historical earthquakes revealed that the three dimension model is close to the reality. The results suggest two potential seismic risk regions in the future: a big earthquake might be located in the east of the 1934 Bihar-Nepal M-w similar to 8. 1 earthquake, and a moderate to major event might take place to the southeast of the aftershock M(w)7. 3 earthquake.","PeriodicalId":55257,"journal":{"name":"地球物理学报","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89787138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Qian, J. Mechie, Changqing Yu, Deutsches GeoForschungsZentrum Publikationen aller GIPP-unte Projekte
{"title":"The spherical analytic relocation technique and its application to local seismic tomography in Longmenshan area","authors":"H. Qian, J. Mechie, Changqing Yu, Deutsches GeoForschungsZentrum Publikationen aller GIPP-unte Projekte","doi":"10.6038/CJG2018M0149","DOIUrl":"https://doi.org/10.6038/CJG2018M0149","url":null,"abstract":"","PeriodicalId":55257,"journal":{"name":"地球物理学报","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74917786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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