Study of the intensity attenuation law in the East China Plain and the northwest of China

ＳｔｕｄｙｏｆｔｈｅｉｎｔｅｎｓｉｔｙａｔｔｅｎｕａｔｉｏｎｌａｗｉｎｔｈｅＥａｓｔＣｈｉｎａＰｌａｉｎａｎｄｔｈｅｎｏｒｔｈｗｅｓｔｏｆＣｈｉｎａ郁曙君Ｓｈｕ－ＪｕｎＹＵ（ＩｎｓｔｉｔｕｔｅｏｆＧｅｏｐｈｙｓｉｃｓ，ＳｔａｔｅＳｅｉｓｍｏｌｏｇｉｃ...     

Investigations of the seismomagnetic effect in the geomagnetic diurnal variations

ＩｎｖｅｓｔｉｇａｔｉｏｎｓｏｆｔｈｅｓｅｉｓｍｏｍａｇｎｅｔｉｃｅｆｆｅｃｔｉｎｔｈｅｇｅｏｍａｇｎｅｔｉｃｄｉｕｒｎａｌｖａｒｉａｔｉｏｎｓＰｏ－ＦａｎｇＣＨＥＮ（陈伯舫）（ＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃｓａｎｄＤｅｐａｒｔｍｅｎｔｏｆＧｅ...     

Regional characteristics of stress field in the southern part of the north－south seismic belt in China and its relation with plate movement

Ｒｅｇｉｏｎａｌｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｓｔｒｅｓｓｆｉｅｌｄｉｎｔｈｅｓｏｕｔｈｅｒｎｐａｒｔｏｆｔｈｅｎｏｒｔｈ－ｓｏｕｔｈｓｅｉｓｍｉｃｂｅｌｔｉｎＣｈｉｎａａｎｄｉｔｓｒｅｌａｔｉｏｎｗｉｔｈｐｌａｔｅ　ｍｏｖｅｍｅｎｔＪｉ－Ｒｅｎ...     

Characteristic of crustal structure in the Shulu fault basin and its vicinity

（王椿镛，张先康，林中洋，李学清）ＣｈａｒａｃｔｅｒｉｓｔｉｃｏｆｃｒｕｓｔａｌｓｔｒｕｃｔｕｒｅｉｎｔｈｅＳｈｕｌｕｆａｕｌｔｂａｓｉｎａｎｄｉｔｓｖｉｃｉｎｉｔｙ￥Ｃｈｕｎ－ＹｏｎｇＷＡＮＧＩ；Ｘｉａｎ－ＫａｎｇＺＨＡＮＧ；Ｚｈｏｎｇ－ＹａｎｇＬ...     

Comparison and analysis of the stress field in the source region of Tangshan and Lancang earthquake sequences

ＣｏｍｐａｒｉｓｏｎａｎｄａｎａｌｙｓｉｓｏｆｔｈｅｓｔｒｅｓｓｆｉｅｌｄｉｎｔｈｅｓｏｕｒｃｅｒｅｇｉｏｎｏｆＴａｎｇｓｈａｎａｎｄＬａｎｃａｎｇｅａｒｔｈｑｕａｋｅｓｅｑｕｅｎｃｅｓＧｕｉ－ＬｉｎｇＤＩＡＯ；（刁桂苓）Ｌｉ－ＭｉｎＹＵ；（于利民）...     

Features of fractal dimension anomaly of radon content in underground water in North China before and after the 1976 Tangshan earthquake

ＦｅａｔｕｒｅｓｏｆｆｒａｃｔａｌｄｉｍｅｎｓｉｏｎａｎｏｍａｌｙｏｆｒａｄｏｎｃｏｎｔｅｎｔｉｎｕｎｄｅｒｇｒｏｕｎｄｗａｔｅｒｉｎＮｏｒｔｈＣｈｉｎａｂｅｆｏｒｅａｎｄａｆｔｅｒｔｈｅ１９７６ＴａｎｇｓｈａｎｅａｒｔｈｑｕａｋｅＣｈａｎｇ－Ｃｈｕ...     

Grouping occurrences being the fundamental feature of the strong earthquakes in Chinese mainland

ＧｒｏｕｐｉｎｇｏｃｃｕｒｒｅｎｃｅｓｂｅｉｎｇｔｈｅｆｕｎｄａｍｅｎｔａｌｆｅａｔｕｒｅｏｆｔｈｅｓｔｒｏｎｇｅａｒｔｈｑｕａｋｅｓｉｎＣｈｉｎｅｓｅｍａｉｎｌａｎｄＱｉｎ－ＺｕＬＩ（李钦祖）；Ｌｉ－ＭｉｎＹＵ（于利民）；Ｊｉ－ＹｉＷＡＮＧ（王吉易...     

Characteristics of tectonic deformation field about strike－slip earthquake－generating structure in the Chinese mainland

Ｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｔｅｃｔｏｎｉｃｄｅｆｏｒｍａｔｉｏｎｆｉｅｌｄａｂｏｕｔｓｔｒｉｋｅ－ｓｌｉｐｅａｒｔｈｑｕａｋｅ－ｇｅｎｅｒａｔｉｎｇｓｔｒｕｃｔｕｒｅｉｎｔｈｅＣｈｉｎｅｓｅｍａｉｎｌａｎｄ环文林，张晓东，宋昭仪Ｗｅｎ－Ｌｉｎ...     

Research on the completeness of earthquake data in the Chinese mainland（I）──North China

ＲｅｓｅａｒｃｈｏｎｔｈｅｃｏｍｐｌｅｔｅｎｅｓｓｏｆｅａｒｔｈｑｕａｋｅｄａｔａｉｎｔｈｅＣｈｉｎｅｓｅｍａｉｎｌａｎｄ（Ｉ）──ＮｏｒｔｈＣｈｉｎａＷｅｉ－ＱｉｏｎｇＨＵＡＮＧ（黄玮琼）；Ｗｅｎ－ＸｉａｎｇＬＩ；（李文香）ａｎｄＸｕｅ－ＦｅｎｇＣ...     

Application of PP cluster method in the earthquake swarm analysis

ＡｐｐｌｉｃａｔｉｏｎｏｆＰＰｃｌｕｓｔｅｒｍｅｔｈｏｄｉｎｔｈｅｅａｒｔｈｑｕａｋｅｓｗａｒｍａｎａｌｙｓｉｓＳｈｉ－ＹｏｎｇＺＨＯＵ；（周仕勇）Ｌｉｎｇ－ＲｅｎＺＨＵ；（朱令人）ａｎｄＣｈｕａｎ－ＬｉｎｇＤＥＮＧ（邓传玲）（Ｓｅｉｓｍｏｌｏｇｉｃ...     

地震供能、储能与放能机制的研究

“双向应变结构”是孕育和发生地震可能的供能、储能与放能的一种机制。它既能缓慢地储存弹性势能与重力势能而孕育地震,又能突然快速地释放弹性势能与重力势能而发生地震。由于地震发生时孕震体是(原应变的)应变逆转的自破裂过程,因此当初始破裂发生后,在破裂的前沿区,地震剪切应力在原有应力集中的基础上,还会再次产生一个突然快速增强(使破裂加速)到快速减弱(使破裂减速到停止)的过程,即产生“应变逆转破裂效应”。这样,不仅会大大增加地震破裂前沿区的剪切应力,而且还会大大减小破裂中的阻力,可能使地震发生中的断层强度佯谬得到解释。“双向应变结构”破裂发生地震的具体物理机制,印证了震源体断层运动的复杂性：既产生了剪切错动的破裂运动,又产生了单向的拉张与单向的压缩运动,同时还产生了整体的膨胀与整体的压缩运动。     

Global shear stress pattern in main seismic active belts

ＧｌｏｂａｌｓｈｅａｒｓｔｒｅｓｐａｔｅｒｎｉｎｍａｉｎｓｅｉｓｍｉｃａｃｔｉｖｅｂｅｌｔｓＬＥＩＸＩＡＯ（肖磊）ＰＥＩ－ＳＨＡＮＣＨＥＮ（陈培善）ＩｎｓｔｉｔｕｔｅｏｆＧｅｏｐｈｙｓｉｃｓ，ＳｔａｔｅＳｅｉｓｍｏｌｏｇｉｃａｌＢｕｒｅａｕ，Ｂｅｉ...     

Application of observed strain steps to the study of remote earthquake stress triggering

IntroductionModernseismologysuggeststhatearthquakesarecausedbyfaultslippingtriggeredbytec-tonicstressesaccumulatedtoacertainextent;andthefaultslip,inturn,releasesstresses.Infact,whenanintensivequakeoccurs,thefracturingoftheseismogenicfaultdoesnotleadtothereleaseofallthestressesbut,accordingtothegeometricrelationsamongthefaults,releasesstressesonsomeofthefaultstomakethemmorestable,whileaccumulatesstressesonotherfaultstomakethemtendtoslip.Asanapproximation,thestrengthofthefaulttobeysByerleylawby…     

Study on determination of stress level by seismic stress drops and the stress axis deflections before and after large earthquakes

Introduction The study of tectonic stress field, a major branch of the Earth science, plays an important role in geodynamics. The world stress map plan started from 1980s and was leaded by Zoback. Lots of scientists from many countries participated this plan. The plan collected global tectonic stress measurements and research results and established global stress database. The world stress map was edited based on the global stress database. The world stress map reflected feature of global li…     

陕西地区环境剪应力的分布特征

利用西安数字地震遥测台网记录的宽频带数字地震资料，测定了陕西地区环境剪应力值τ0的分布，结果显示陕西地区存在着环境剪应力值τ0的高值区，最后对其与地质构造和地震活动性之间的关系进行了探讨。     

新疆两次强震前后地震视应力变化

选取了喀什数字地震台记录的喀什及周边地区地震的宽频带波形资料,分析处理了2001～2005年Ms 3.5以上地震164次,通过数字地震波谱计算了标量地震矩和地震辐射能量,从而进行了视应力的计算.给出了巴楚-伽师Ms 6.8和乌什Ms 6.3强震前后视应力的时序变化情况,发现其视应力均表现出震前低应力阶段-主震前的逐渐上升-震后逐渐恢复的动态变化过程,即地震的孕震-发震-震后调整的阶段性变化特征.这一结果可为喀什及周边地区今后进行地震预测预报研究提供参考依据,对该区开展数字地震方面的研究也有所帮助.     

Stress Sensitivity of Seismic and Electric Rock Properties of the Upper Continental Crust at the KTB

We test the hypothesis that the general trend of P-wave and S-wave sonic log velocities and resistivity with depth in the pilot hole of the KTB site Germany, can be explained by the progressive closure of the compliant porosity with increasingly effective pressure. We introduce a quantity θ_c characterizing the stress sensitivity of the mentioned properties. An analysis of the downhole measurements showed that estimates of the quantitiy θ_c for seismic velocities and electrical formation factor of the in situ formation coincide. Moreover, this quantity is 3.5 to 4.5 times larger than the averaged stress sensitivity obtained from core samples. We conclude that the hypothesis mentioned above is consistent with both data sets. Moreover, since θ_c corresponds approximately to the inverse of the effective crack aspect ratio, larger in situ estimates of θ_c might reflect the influence of fractures and faults on the stress sensitivity of the crystalline formation in contrast to the stress sensitivity of the nearly intact core samples. Finally, because the stress sensitivity is directly related to the elastic nonlinearity we conclude that the elastic nonlinearity (i.e., deviation from linear stress-strain relationship i.e., Hooke's law) of the KTB rocks is significantly larger in situ than in the laboratory.     

川东南地区地震视应力时空分布特征

利用四川数字地震台网记录资料,计算2008年汶川地震后,川东南地区ML 3.0以上地震的震源动力学参数特征,分别得到视应力、应力降与震级之间、震级和地震矩之间,以及地震矩和视应力之间的定标关系。通过扣除震级影响,计算归准化视应力值的时空变化特征。得到结果如下:1从时间分布图来看,研究区4级以上地震频发时段刚好对应视应力涨落较明显时段,而该时段当地工业采矿注水活动强烈,故该区域视应力水平或许反映了工业活动对区域应力场的影响;2从空间分布图来看,自贡隆昌一带震级偏大,视应力反而偏小的现象可能与该区域应力释放不充分、构造应力水平偏低有关,未来要关注该区域发生中强地震的可能。     

Deep mantle flow, global tectonic pattern and the background of seismic stress field in China

In this paper we investigate the sources of two kinds of forces to form the stress field in the lithosphere. These are the drag force caused by mantle flow and the force system along plate boundaries. The results show that both forces control the basic stress pattern in China and compressive stresses can fit with the stress patterns constructed by focal mechanisms,in-situ stress measurements in boreholes and that deduced from other geophysical and geological observation. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 295–306, 1991. This research is sponsored by the Chinese Joint Seismological Science Fundation.