Relocation of the 1998 Zhangbei-Shangyi earthquake sequence using the double difference earthquake location algorithm

Introduction On January 10, 1998, at 11h50min Beijing Time (03h50min UTC), an earthquake of ML=6.2 occurred in the border region between the Zhangbei County and Shangyi County of Hebei Province. In total 87 events with ML3.0 were recorded by Beijing Telemetry Seismic Network (BTSN) before March of 1999. Before relocation the preliminary hypocenters determined by BTSN showed an epicentral distribution of 25 km long and 25 km wide without any predominate orientation. The epicentral a…     

Study on the earthquake fault of the Lulong ML=6.2 earthquake by precise relocation of aftershock

Introduction The Lulong county is about 75 km northeast to Tangshan in Hebei Province. An earthquake of ML=6.2 took place on October 19, 1982 about 4 km northeast to the county town. The epicenter of the mainshock is located at 39°57′N, 119°04′E by the Beijing seismic network. The 1976 Tang- shan 7.8 earthquake and the successive Luanxian 7.1, Ninghe 6.9 and the Lulong earthquake spread in NE-SW direction in space. SONG and WANG et al of Institute of Geophysics, China Seismolog…     

Strong earthquake activity all over the world and strong-moderate earthquake activity within and nea

Ｓｔｒｏｎｇｅａｒｔｈｑｕａｋｅａｃｔｉｖｉｔｙａｌｌｏｖｅｒｔｈｅｗｏｒｌｄａｎｄｓｔｒｏｎｇ－ｍｏｄｅｒａｔｅｅａｒｔｈｑｕａｋｅａｃｔｉｖｉｔｙｗｉｔｈｉｎａｎｄｎｅａｒＣｈｉｎａ（Ｆｅｂｒｕａｒｙ,１９９８－Ｍａｒｃｈ,１９９８）ＰＥＩ－ＳＨ...     

Preliminary study on the duration of earthquake activity

ＰｒｅｌｉｍｉｎａｒｙｓｔｕｄｙｏｎｔｈｅｄｕｒａｔｉｏｎｏｆｅａｒｔｈｑｕａｋｅａｃｔｉｖｉｔｙＦｕ－ＭｉｎｇＨＵＡＮＧ（黄福明）（ＩｎｓｔｉｔｕｔｅｏｆＣｒｕｓｔａｌＤｙｎａｍｉｃｓ，ＳｔａｔｅＳｅｉｓｍｏｌｏｇｉｃａｌＢｕｒｅａｕ，Ｂｅｉｊｉｎ...     

Analysis of the geothermal vortexes triggering the Xingtai earthquake in 1966

ＡｎａｌｙｓｉｓｏｆｔｈｅｇｅｏｔｈｅｒｍａｌｖｏｒｔｅｘｅｓｔｒｉｇｇｅｒｉｎｇｔｈｅＸｉｎｇｔａｉｅａｒｔｈｑｕａｋｅｉｎ１９６６ＭＡＯＣＡＮＧＴＡＮＧ（汤懋苍）ＸＩＡＯＱＩＮＧＧＡＯ（高晓清）ＬａｎｚｈｏｕＩｎｓｔｉｔｕｔｅｏｆＰｌａｔｅ...     

Seismicity anomalies before the great earthquake of M_S=8.1 in the Kunlun Pass and its significance to earthquake prediction

Introduction The MS=8.1 earthquake occurred in west of the Kunlun Pass on November 14, 2001. It is the greatest earthquake occurred in China since the last half of the century and is an important event in recent seismic history of China. Some specialists consider that the earthquake occurred in the area where the earthquake monitoring capability is lowest in Chinese mainland; no striking precursory seismicity was found. The study on the precursory seismicity before the earthquake has not b…     

The GIS and analysis of earthquake damage distribution of the 1303 Hongtong M=8 earthquake

Introduction The 1303 Hongtong earthquake is an important earthquake in the eastern China. There is a lot of information in historical documents about the earthquake and many traces destroyed by the earthquake in the southern Shanxi Province. Many scholars have studied the earthquake from dif-ferent aspects, but mainly limited the definitions of the isoseismal and three factors of the earth-quake. Owing to being limited by the analysis technique, many useful damage information of the earthqu…     

The fracture characteristic of the 1989 Datong-Yanggao earthquake sequence

Ｔｈｅｆｒａｃｔｕｒｅｃｈａｒａｃｔｅｒｉｓｔｉｃｏｆｔｈｅ１９８９Ｄａｔｏｎｇ－ＹａｎｇｇａｏｅａｒｔｈｑｕａｋｅｓｅｑｕｅｎｃｅＳｉ－ＣｈａｎｇＺＨＡＮＧ（张四昌），Ｇｕｉ－ＬｉｎｇＤＩＡＯ（刁桂苓）ａｎｄＬｉ－ＭｉｎＹＵ（于利民）（Ｓｅｆｒｍｏ...     

The initial subevent of the 1994 Northridge, California, earthquake: Is earthquake size predictable?

We examine the initial subevent (ISE) of the M 6.7, 1994 Northridge, California, earthquake in order to discriminate between two end-member rupture initiation models: the preslip and cascade models. Final earthquake size may be predictable from an ISE's seismic signature in the preslip model but not in the cascade model. In the cascade model ISEs are simply small earthquakes that can be described as purely dynamic ruptures. In this model a large earthquake is triggered by smaller earthquakes; there is no size scaling between triggering and triggered events and a variety of stress transfer mechanisms are possible. Alternatively, in the preslip model, a large earthquake nucleates as an aseismically slipping patch in which the patch dimension grows and scales with the earthquake's ultimate size; the byproduct of this loading process is the ISE. In this model, the duration of the ISE signal scales with the ultimate size of the earthquake, suggesting that nucleation and earthquake size are determined by a more predictable, measurable, and organized process. To distinguish between these two end-member models we use short period seismograms recorded by the Southern California Seismic Network. We address questions regarding the similarity in hypocenter locations and focal mechanisms of the ISE and the mainshock. We also compare the ISE's waveform characteristics to those of small earthquakes and to the beginnings of earthquakes with a range of magnitudes. We find that the focal mechanisms of the ISE and mainshock are indistinguishable, and both events may have nucleated on and ruptured the same fault plane. These results satisfy the requirements for both models and thus do not discriminate between them. However, further tests show the ISE's waveform characteristics are similar to those of typical small earthquakes in the vicinity and more importantly, do not scale with the mainshock magnitude. These results are more consistent with the cascade model.     

The variations of the degree of ground resistivity anisotropy during the Tangshan earthquake

ＴｈｅｖａｒｉａｔｉｏｎｓｏｆｔｈｅｄｅｇｒｅｅｏｆｇｒｏｕｎｄｒｅｓｉｓｔｉｖｉｔｙａｎｉｓｏｔｒｏｐｙｄｕｒｉｎｇｔｈｅＴａｎｇｓｈａｎｅａｒｔｈｑｕａｋｅＴｏｎｇ－ＥｎＭＡＯ（毛桐恩）；Ｔｉｅ－ＣｈｅｎｇＷＡＮＧ（王铁成）；Ｊｉａ－ＬｉｕＹＡＯ...     

Spheroidal oscillations of the Earth stimulated by the Sumatra-Andaman earthquake with CDSN data

The 0S2~0S54 spheroidal modes of Earth’s free oscillations, triggered by the great Sumatra-Andaman earthquake of 26 December 2004 are retrieved from VHZ data recorded by seven upgraded stations of China Digital Seismograph Network (CDSN). We compare these spheroidal modes with theoretical free oscillation spectra calculated from the Preliminary Reference Earth Model (PREM) and find a coincidence between their periods. Spectral splitting phenomenon is observed obviously in 0S2, 0S3, 0S4, 2S1 and 1S2 free oscillation modes. What is most noticeable is that the oscillation mode 2S1 is reported for the second time (the first time by Rosat et al) without any data stacking. We simulated the split singlet of 0S2 mode on seven CDSN stations based on general focal mechanism and seismic moment of the earthquake. The result shows that seismic moment of the earthquake can reach 1023 N.m. We also find that the recording of Earth’s free oscillations carries abundant information of source mechanism and earthquake location, which is applicable to the detailed study of source rupture parameters.     

Relocation and seismogenic structure of the 1998 Zhangbei-Shangyi earthquake sequence

Introduction The January 10, 1998 Zhangbei-Shangyi, Hebei Province, earthquake has been the third large event of magnitude 6.0 and greater since the 1976 great Tangshan earthquake of magnitude 7.8 in the northern China (33皛42癗, 110皛124癊). Before this event, there were only two events of magnitude 6.0 and greater occurred in or around the Tangshan area since 1976: the M=6.9 Ninghe, Tianjin, earthquake of November 15, 1976 and the M=6.2 Hangu, Tianjin, earthquake of May 12, 1977. The …     

The numerical simulation of thesource development of the Tangshan earthquake

Ｔｈｅｎｕｍｅｒｉｃａｌｓｉｍｕｌａｔｉｏｎｏｆｔｈｅｓｏｕｒｃｅｄｅｖｅｌ┐ｏｐｍｅｎｔｏｆｔｈｅＴａｎｇｓｈａｎｅａｒｔｈｑｕａｋｅＺＨＩ－ＲＥＮＮＩＵ（牛志仁）ＤＡＮＧ－ＭＩＮＣＨＥＮ（陈党民）ＢＩＮＧ－ＱＩＡＮＬＩ（李炳乾）Ｓｅｉｓｍｏｌｏ...     

Experimental examination on the heterogeneity parameter C_v of earthquake precursors

Introduction Many earthquake cases indicate that there exists obvious heterogeneity in temporal-spatial distribution of earthquake precursors (FENG, 1983; MEI, et al, 1993). Therefore, it is very crucial for the study of earthquake prediction to describe the heterogeneity in temporal-spatial distribution of earthquake precursors and to understand its physical mechanism. Up to now, a lot of useful researches have been done in this field. Recently, WANG, et al (1999) and CHEN, et al (2000)…     

Automatic recognition of damaged town buildings caused by earthquake using remote sensing information: Taking the 2001 Bhuj, India, earthquake and the 1976 Tangshan, China, earthquake as examples

Introduction As we well know, the hazard of earthquake is very wide especially in cities. The conventionalmethods to investigate the damage are difficult to meet the requirements in applications. In recentyears, with the rapid development of remote sensing, especially the successful launch and applica-tion of high-resolution commercial remote sensing satellite, it has become possible to recognize andextract damage information by using remote sensing. The researchers at home and abroad hav…     

Numerical analysis of the interaction of soil-structure under earthquake loading

Ｎｕｍｅｒｉｃａｌａｎａｌｙｓｉｓｏｆｔｈｅｉｎｔｅｒａｃｔｉｏｎｏｆｓｏｉｌ┐ｓｔｒｕｃｔｕｒｅｕｎｄｅｒｅａｒｔｈｑｕａｋｅｌｏａｄｉｎｇＧＥＮ－ＤＥＺＨＡＮＧ１）（章根德）ＳＨＵ－ＣＨＥＮＧＮＩＮＧ２）（宁书成）１）ＩｎｓｔｉｔｕｔｅｏｆＭｅ...     

An example of earthquake nucleation of the strong continental earthquakes

IntroductionThe study on earthquake nucleation is widely concerned by seismologists in the world. The experimental and theoretical studies indicate that earthquakes should be preceded by quasi-static slip within a nucleation zone (Ohnaka, 1992; Dodge, Beroza, 1995; Dodge, et al, 1996; Ohnaka, Kuwahara, 1990; Yamashita, Ohnaka, 1991). The earthquake nucleation process means a transition from quasi-static to quasi-dynamic rupture process, and it itself is a short-term precursor. Immediate fo…     

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...     

The earthquake distribution and the resistivity structure in the Chinese mainland（Ⅰ）

ＴｈｅｅａｒｔｈｑｕａｋｅｄｉｓｔｒｉｂｕｔｉｏｎａｎｄｔｈｅｒｅｓｉｓｔｉｖｉｔｙｓｔｒｕｃｔｕｒｅｉｎｔｈｅＣｈｉｎｅｓｅｍａｉｎｌａｎｄ（Ⅰ）ＣＨＡＮＧ－ＦＡＮＧＸＵ（徐常芳）（ＩｎｓｔｉｔｕｔｅｏｆＧｅｏｌｏｇｙ，ＳｔａｔｅＳｅｉｓｍｏｌｉｇ...     

Development of attenuation relation for the near fault ground motion from the characteristic earthquake

A composite source model has been used to simulate a broadband strong ground motion with an associated fault rupture process. A scenario earthquake fault model has been used to generate 1 000 earthquake events with a magni-tude of Mw8.0. The simulated results show that, for the characteristic event with a strike-slip faulting, the character istics of near fault ground motion is strongly dependent on the rupture directivity. If the distance between the sites and fault was given, the ground motion in the forward direction (Site A) is much larger than that in the backward direction (Site C) and that close to the fault (Site B). The SH waves radiated from the fault, which corresponds to the fault-normal component plays a key role in the ground motion amplification. Corresponding to the sites A, B, and C, the statistical analysis shows that the ratio of their aPG is 2.15:1.5:1 and their standard deviations are about 0.12, 0.11, and 0.13, respectively. If these results are applied in the current probabilistic seismic hazard analysis (PSHA), then, for the lower annual frequency of exceedance of peak ground acceleration, the predicted aPG from the hazard curve could reduce by 30% or more compared with the current PSHA model used in the developing of seismic hazard map in the USA. Therefore, with a consideration of near fault ground motion caused by the rupture directivity, the regression model used in the development of the regional attenuation relation should be modified accordingly.