Pore presure in deep bore-holes:Its measurement and relation with seismic activities

Ｐｏｒｅｐｒｅｓｕｒｅｉｎｄｅｐｂｏｒｅｈｏｌｅｓ：ＩｔｓｍｅａｓｕｒｅｍｅｎｔａｎｄｒｅｌａｔｉｏｎｗｉｔｈｓｅｉｓｍｉｃａｃｔｉｖｉｔｉｅｓＪＩＡＮＬＩＧＡＯ（高建理）ＳＨＩＺＯＮＧＳＵＮ（孙世宗）ＪＩＡＮＭＩＮＤＩＮＧ（丁健民）ＧＵ...     

Study of a 3-D seismic gap

Ｓｔｕｄｙｏｆａ３ＤｓｅｉｓｍｉｃｇａｐＹＵＡＮＱＩＮＧＺＨＵ１）（朱元清）ＣＯＮＧＪＵＮＸＩＡ１）（夏从俊）ＧＥＴＵＺＵＯＬＩ２）（左力格图）ＨＵＩＭＩＮＬＩ１）（李慧民）１）ＳｅｉｓｍｏｌｏｇｉｃａｌＢｕｒｅａｕｏｆＳｈａｎｇｈａｉ，...     

Seismic wave propagation in viscoelastic and saturated rock

ＳｅｉｓｍｉｃｗａｖｅｐｒｏｐａｇａｔｉｏｎｉｎｖｉｓｃｏｅｌａｓｔｉｃａｎｄｓａｔｕｒａｔｅｄｒｏｃｋＹＵＡＮＱＩＡＮＧＣＡＩ（蔡袁强）ＣＨＡＮＧＪＩＥＸＵ（徐长节）ＳＨＩＭＩＮＧＷＵ（吴世明）ＤｅｐａｒｔｍｅｎｔｏｆＣｉｖｉｌＥｎｇｉｎｅ...     

Application research of seismic method in assessment of active fault

ＡｐｐｌｉｃａｔｉｏｎｒｅｓｅａｒｃｈｏｆｓｅｉｓｍｉｃｍｅｔｈｏｄｉｎａｓｅｓｍｅｎｔｏｆａｃｔｉｖｅｆａｕｌｔＭＩＮＧＣＡＩＸＵ（徐明才）ＪＩＮＧＨＵＡＧＡＯ（高景华）ＭＩＮＧＴＡＯＣＨＡＩ（柴铭涛）ＧＵＡＮＧＫＥＷＡＮＧ（王广科）ＪＩ...     

Estimation of seismic stress drop from the peak velocity of ground motion

ＥｓｔｉｍａｔｉｏｎｏｆｓｅｉｓｍｉｃｓｔｒｅｓｄｒｏｐｆｒｏｍｔｈｅｐｅａｋｖｅｌｏｃｉｔｙｏｆｇｒｏｕｎｄｍｏｔｉｏｎＪＩＡＺＨＥＮＧＱＩＮ（秦嘉政）ＺＵＹＩＮＬＩＵ（刘祖荫）ＸＩＡＯＤＯＮＧＱＩＡＮ（钱晓东）ＱＩＮＧＹＩＮＸＩＥ（谢庆...     

Some results of modeling D-D seismogenic pattern by the fracture model experiment of large-scale rock samples(I)

ＳｏｍｅｒｅｓｕｌｔｓｏｆｍｏｄｅｌｉｎｇＤＤｓｅｉｓｍｏｇｅｎｉｃｐａｔｅｒｎｂｙｔｈｅｆｒａｃｔｕｒｅｍｏｄｅｌｅｘｐｅｒｉｍｅｎｔｏｆｌａｒｇｅ－ｓｃａｌｅｒｏｃｋｓａｍｐｌｅｓ（Ｉ）ＹＡＮＧ－ＱＵＡＮＬＵ１）（陆阳泉）ＪＩＡ－ＬＩＵＺＨＡ...     

Crustal deformation of seismogenic fault and its surrounding area after the Tangshane arthquake

ＣｒｕｓｔａｌｄｅｆｏｒｍａｔｉｏｎｏｆｓｅｉｓｍｏｇｅｎｉｃｆａｕｌｔａｎｄｉｔｓｓｕｒｏｕｎｄｉｎｇａｒｅａａｆｔｅｒｔｈｅＴａｎｇｓｈａｎｅａｒｔｈｑｕａｋｅＪＵＥＭＩＮＸＩＥ（谢觉民）ＲＵＯＢＡＩＷＡＮＧ（王若柏）ＷＡＮＧＪＵＢＯ（...     

Reflection and transmission of seismic waves at an interface betwen two saturated soils

ＲｅｆｌｅｃｔｉｏｎａｎｄｔｒａｎｓｍｉｓｉｏｎｏｆｓｅｉｓｍｉｃｗａｖｅｓａｔａｎｉｎｔｅｒｆａｃｅｂｅｔｗｅｎｔｗｏｓａｔｕｒａｔｅｄｓｏｉｌｓＪＵＮＹＡＮＧ（杨峻）ＳＨＩＭＩＮＧＷＵ（吴世明）ＺｈｅｊｉａｎｇＵｎｉｖｅｒｓｉｔｙ，Ｈａｎｇｚ...     

Study of crustal seismic velocity in the Weihe fault depression basin by seismic tomographic imaging

ＳｔｕｄｙｏｆｃｒｕｓｔａｌｓｅｉｓｍｉｃｖｅｌｏｃｉｔｙｉｎｔｈｅＷｅｉｈｅｆａｕｌｔｄｅｐｒｅｓｉｏｎｂａｓｉｎｂｙｓｅｉｓｍｉｃｔｏｍｏｇｒａｐｈｉｃｉｍａｇｉｎｇＧＵＡＮＧＹＩＮＧＸＵＥ１）（薛广盈）ＹＵＮＹＵＤＩＮＧ２）（丁韫玉）ＺＨ...     

CalculationoflongperiodresponsespectratoearthquakegroundmotionfromseismogramsofType513seismographs

ＣａｌｃｕｌａｔｉｏｎｏｆｌｏｎｇｐｅｒｉｏｄｒｅｓｐｏｎｓｅｓｐｅｃｔｒａｔｏｅａｒｔｈｑｕａｋｅｇｒｏｕｎｄｍｏｔｉｏｎｆｒｏｍｓｅｉｓｍｏｇｒａｍｓｏｆＴｙｐｅ５１３ｓｅｉｓｍｏｇｒａｐｈｓＹＡＮＸＩＡＮＧＹＵ（俞言祥）ＳＵＹＵＮＷＡＮ...     

On the seismicity of central Kamchatka before the 1997, M = 7.9 Kronotskii earthquake

We report results from a detailed study of seismicity in central Kamchatka for the period from 1960 to 1997 using a modified traditional approach. The basic elements of this approach include (a) segmentation of the seismic region concerned (the Kronotskii and Shipunskii geoblocks, the continental slope and offshore blocks), (b) studying the variation in the rate of M = 4.5–7.0 earthquakes and in the amount of seismic energy release over time, (c) studying the seismicity variations, (d) separate estimates of earthquake recurrence for depths of 0–50 and 50–100 km. As a result, besides corroborating the fact that a quiescence occurred before the December 5, 1997, M = 7.9 Kronotskii earthquake, we also found a relationship between the start of the quiescence and the position of the seismic zone with respect to the rupture initiation. The earliest date of the quiescence (decreasing seismicity rate and seismic energy release) was due to the M = 4.5–7.0 earthquakes at depths of 0–100 km in the Kronotskii geoblock (8–9 years prior to the earthquake). The intermediate start of the quiescence was due to distant seismic zones of the Shipunskii geoblock and the circular zone using the RTL method, combining the Shipunskii and Kronotskii geoblocks (6 years). Based on the low magnitude seismicity (M≥2.6) at depths of 0–70 km in the southwestern part of the epicentral zone (50–100 km from the mainshock epicenter), the quiescence was inferred to have occurred a little over 3 years (40 months) before the mainshock time and a little over 2 years (25 months) in the immediate vicinity of the epicenter (0–50 km). These results enable a more reliable identification of other types of geophysical precursors during seismic quiescences before disastrous earthquakes.     

On the seismic regime network method

In this paper, based on the previous study of practical use of seismic regime windows and seismic regime belts, the problem of establishing a “seismic regime network” consisting of “windows” and “belts” is further posed and discussed according to the observed fact that many “windows” and “belts” make responses to one earthquake. For the convenience of usage, the “seismic regime network” is divided into two classes, the first class and the second one. The former can be used in tendency prediction for long-term seismic activity in a large area, the latter used in short-term prediction in a small area. In this paper, after briefly discussing the physical significance of “seismic regime network”, it is pointed out that this simple and easily used method can be used to observe and extract seismic precursory information from a large area before a great earthquake, thus it can provide a reliable basis for the analysis and judgement of seismic regime tendency in time and space. No doult, this method is of certain practical significance. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 161–169, 1991. The English version of this paper is improved by Prof. Shaoxie Xu.     

汶川地震频次场异常特征分析

地震频次场是描述地震发生频次时空特征的一种数学方法。将2008年5月12日汶川8.0级地震震中附近区域（30.0°~33.0° N、101.5°~105.5° E）作为研究对象,以自然正交函数展开方法分析频次场典型场时间因子的时间变化特征。当取前8个特征值对应的典型场时,拟合精度可达0.936 8;其中6个典型场显示有异常变化,占总场比重的0.691 1;异常出现时间最早在2004年9月,即震前3年7个月,最迟在震前1个多月,表现出短临异常特征。研究结果表明利用地震频次场方法能够较为理想地提取汶川8.0级地震震前异常。     

2008年10月5日乌恰6.9级地震短临异常研究

对2008年10月5日乌恰6.9级地震前短临异常特征进行了分析总结。强震前短临前兆特征为:①在空区内发生标志地震后围空区附近断裂发生预警地震;②与背景性条带相交出现前兆性小震条带;③地震波低值区出现高值回返;④地震活动异常增强—前兆性平静基础上出现短期增强及新疆大范围地震活动增强;⑤地磁垂直分量低值回返。     

Probable satellite thermal infrared anomaly before the Zhangbei M s=6.2 earthquake on January 10, 1998

This paper used the thermal infrared data of the satellite NOAA-AAVHRR of the north part of North China (113°～119° E, 38°～42° N), and processed the remote sensing data through radiation adjustment, geometric adjustment and so on by the software ＂The Monitoring and Fast Process System of Earthquake Precursor Thermal Infrared Anomaly＂, inversed the earth surface temperature. Some disturbances effect had been excluded, and thermal infrared temperature anomaly had been extracted by the picture difference method. The Zhangbei MS=6.2 earthquake is used as the example in the paper, so that in the paper thermal infrared characteristics on time-space before earthquake and the relationship between the anomaly and the earthquake prediction have been summarized.Within more than ten days before the Zhangbei earthquake, the thermal infrared anomaly had emerged widely along Zhangjiakou-Bohai seismic belt, and the anomalous region seemed like a belt and it is also consistent with the tectonic background there; the anomaly expanded from the outside toward the earthquake focus, but the focus lay at the edge of the thermal infrared region. So it is possible to explore a new anomaly observation method for earthquake prediction by observing and studying the satellite thermal infrared anomaly before big earthquakes happen.     

2007年6月3日云南宁洱6.4级地震异常特征分析

通过对2007年6月3日滇西南宁洱6.4级地震前地震活动和前兆异常跟踪,震前对该地震作了短期预测.宁洱6.4级地震前,云南和滇西南地区的6级、5.8级以上地震出现了长时间的平静,显示了能量的积累过程;中期阶段4.5～5.0级地震在震中区周围形成了地震密集区,中、短期阶段滇西南地区MS≥3地震活动显著增强并形成空区,空区长轴250 km,计算震级为6.37,这与实际发生地震震级完全一致.滇西南地区的前兆异常显示,距离震源区近的以趋势异常为主,外围异常以突变为主.     

山西地区6次MS≥4.5地震前地震活动异常总结

系统梳理了2000年以来山西地区6次M_S≥4.5地震前地震活动异常,结果表明,地震空区/平静、地震条带、显著地震/震群、大同地震窗“开窗”活动等异常在地震发生前具有一定普遍性,且异常基本围绕在震中及附近地区分布,特别是在地震平静/空区、地震条带等异常发展后期出现的显著地震/震群活动,对未来地震发生的地点和时间具有较好的预测意义。异常持续时间与发震间隔统计表明：异常多出现在主震发生前6个月以内,显著地震/震群、大同地震窗“开窗”对未来主震的发生具有短临预测意义。此外,随着区域应力水平的不断增强,在特定敏感地区会发生成组极微震密集活动,监视跟踪这些有别于正常活动背景的极微震活动,对地震短临预测具有一定意义。     

新疆天山近7级地震前震群活动的时空分布演化特征

通过普查与系统研究发现, 新疆天山近7级强震之前, 震群活动携带了丰富震兆信息。 主要结果如下: ① 震前1年半至3年多, 包括未来强震震中在内的整个地震带或某一区段震群活动明显增强; ② 在未来强震震中附近, 震群的数量最多且空间分布最为集中, 这些大量密集的震群构成的震群环包围了未来主震震中, 即形成震群空区或空段。 震群空区或空段的几何形状大多为椭圆, 其最大尺度约200 km; ③ 强震之前, 震群数量的多少, 随未来强震震级的增加而增加; ④ 个别强震前几个月, 震群增加的速率有加快的趋势, 同时震群空区内出现填空, 可作为近7级强震进入短期异常阶段的参考标志。 最后, 对所得结果的物理机制以及在地震预报中的应用等问题进行了讨论。     

Unstable fault deformation and information synthesis

ＵｎｓｔａｂｌｅｆａｕｌｔｄｅｆｏｒｍａｔｉｏｎａｎｄｉｎｆｏｒｍａｔｉｏｎｓｙｎｔｈｅｓｉｓＷＡＮ－ＪＵＢＯ（薄万举），ＪＵＥ－ＭＩＮＸＩＥ（谢觉民）ａｎｄＧＵＡＮ－ＳＨＯＵＬＯＵ（楼关寿）ＦｉｒｓｔＣｒｕｓｔａｌＤｅｆｏｒｍａｔｉｏｎＭｏｎｉｔ...     

A kind of information on short-term and imminent earthquake precursors—research on atmospheric electric field anomalies before earthquakes

The long-time practice of observational research on earthquake prediction has shown that the information on short-term and imminent earthquake precursors can hardly be detected, but it is very important for practical and effective earthquake prediction. The result of analysis and study in this paper has shown that the anomaly of quasi-static atmospheric electric field may be a kind of reliable information on short-term and imminent earthquake precursors. On such a basis, the 20 years’ continuous and reliable data of atmospheric electric field observed at the Baijiatuan seismic station are used to study the correlation between the anomalies in seismic activity and relative quiet periods bear on the occurrence of near earthquakes within 200 km range around Beijing after the Tangshan earthquake. The observational results recently reported before hand in written form and earthquakes that actually occurred in near field in corresponding time periods are compared and analyzed. The efficacy of these written prediction opinions about near earthquakes in the recent 10 years is tested. From the test results, the brilliant prospect that the anomaly of quasi-static atmospheric electric field may really become a reliable mark for making short-term and imminent earthquake predictions is discussed. Besides, as a preliminary step, some judgment indexes for predicting earthquakes by use of the observational data of atmospheric electric field before earthquakes are put forward. In the last part, it is pointed out that it would be possible to obtain more believable judgment indexes for determining the three elements of near earthquakes before greater earthquakes (M _S≥5) only if a relatively reasonable station network (2–4 stations every 10 000 km²) is deployed and further investigation is made. Contribution No. 97A0040, Institute of Geophysics, State Seismological Bureau, China. This subject is sponsored by Program No. 95-04-05-01-04, State Seismological Bureau, China.