The mutation sequence of earth resistivity and earthquakes

ＴｈｅｍｕｔａｔｉｏｎｓｅｑｕｅｎｃｅｏｆｅａｒｔｈｒｅｓｉｓｔｉｖｉｔｙａｎｄｅａｒｔｈｑｕａｋｅｓＸｉｎ－ＨｅｎｇＬＩＵ（刘心恒）ａｎｄＹｕｎ－ＳｈｅｎｇＺＨＯＵ（周郧生）（ＳｅｉｓｍｏｌｏｇｉｃａｌＢｕｒｅａｕｏｆＹｕｎｎａｎＰｒｏｖｉｎｃｅ，...     

The pattern characteristics of the tendency variations of earth resistivity and its relation to earthquakes

ＴｈｅｐａｔｔｅｒｎｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｔｈｅｔｅｎｄｅｎｃｙｖａｒｉａｔｉｏｎｓｏｆｅａｒｔｈｒｅｓｉｓｔｉｖｉｔｙａｎｄｉｔｓｒｅｌａｔｉｏｎｔｏｅａｒｔｈｑｕａｋｅｓＨｅ－ＹｕｎＺＨＡＯ（赵和云）（ＥａｒｔｈｑｕａｋｅＲｅｓｅａｒ...     

The crustal fluid evolution and the causes of earthquakes(Ⅲ)

Ｔｈｅｃｒｕｓｔａｌｆｌｕｉｄｅｖｏｌｕｔｉｏｎａｎｄｔｈｅｃａｕｓｅｓｏｆｅａｒｔｈｑｕａｋｅｓ（Ⅲ）ＣＨＡＮＧ－ＦＡＮＧＸＵ（徐常芳）ＩｎｓｔｉｔｕｔｅｏｆＧｅｏｌｏｇｙ，ＳｔａｔｅＳｅｉｓｍｏｌｏｇｉｃａｌＢｕｒｅａｕ，Ｂｅｉｊｉｎｇ１０００...     

The change of the earth’s dimensions determined from paleogeographical data

Summary It is shown that paleogeographical data give evidence for the increase of the Earth’s radius. The average annual increase computed is 0.5 mm/year. The formation of the continents and ocean basins may be easily explained on the basis of the Earth’s expansion. The rate of the annual radius increase derived from this explanation is in good agreement with the value determined from paleogeographical data. The theoretically computed duration of a transgression-regression period corresponds also with geological observations. Prof. Dr. L. Egyed, Geophysical Institute, E?tv?s-University,Budapest (Hungary).     

Simulation of non-stationary ground motion processes(I)

Introduction Up to now,simulation of non-stationary ground motion processes in engineering usually is bygenerating stationary ground motion processes,then making them non-stationary by an enve-lope function(Amin and Ang,1968);and the envelope function is usually calculated based on sta-tistical analysis of ground motion records,and the stationary ground motion processes are simu-lated using filtering method,spectral representation method,or time domain method,etc.Because the envelope function …     

Simulation of non-stationary ground motion processes (II)

Introduction When doing Monte Carlo analysis of stochastic earthquake response of nonlinear structures, it is necessary to have a great number of ground motion processes with an identical statistical feature; In theoretical analysis of earthquake resistance of structures, to study the effect of one parameter, it is required to keep other parameters fixed, and it is often needed one set of ground motion proc-esses having an identical statistical feature; Similarly, while doing structural model…     

The synthetical elastic characteristic parameters of earth tide and its abnormal precursor evolution

ＴｈｅｓｙｎｔｈｅｔｉｃａｌｅｌａｓｔｉｃｃｈａｒａｃｔｅｒｉｓｔｉｃｐａｒａｍｅｔｅｒｓｏｆｅａｒｔｈｔｉｄｅａｎｄｉｔｓａｂｎｏｒｍａｌｐｒｅｃｕｒｓｏｒｅｖｏｌｕｔｉｏｎＹＡＮ－ＢＩＮＺＨＡＮＧ（张雁滨）ＪＵＮＪＩＡＮＧ（蒋骏）ＸＵ－ＤＯＮＧＬ...     

Rare earth element and yttrium compositions of the Paleoproterozoic Yuanjiacun BIF in the Lüliang area and their implications for the Great Oxidation Event(GOE)

In China, most Precambrian banded iron formations(BIFs) are situated in the North China Craton. The Yuanjiacun iron deposit, located in the Lüliang area, is arguably the most representative Superior-type BIF. This iron deposit is coherent with the sedimentary rock succession of the Yuanjiacun Formation in the lower Lüliang Group, and was interpreted to be deposited at 2.3–2.1 Ga, based on ages of overlying and underlying volcanic strata. This age overlaps with the time range of the Great Oxidation Event(GOE, 2.4–2.2 Ga). The Yuanjiacun BIF consists mainly of subhedral-xenomorphic magnetite and quartz and rarely other minerals with a lower degree of metamorphism, from greenschist to lower amphibolite facies. The geochemical characteristics of this BIF are similar to those of Superior-type BIFs. Prominent positive La, Y, and Eu anomalies normalized by the Post Archean Australian Shale(PAAS) indicate that the primary chemical precipitate is a result of solutions that represent mixtures of seawater and high-T hydrothermal fluids. The contamination from crustal detritus found is negligible based on low abundances of Al2O3 and TiO2(0.5%) and of trace elements such as Th, Hf, Zr, and Sc(1.5 ppm), as well as the lack of co-variations between Al2O3 and TiO2. In particular, the Yuanjiacun BIF samples do not display significant negative Ce anomalies like those of the Archean iron formations, but rather, the Yuanjiacun BIF samples exhibit prominent positive Ce anomalies, low Y/Ho ratios, and high light to heavy REE((Pr/Yb)SN) ratios, which are essentially consistent with the late Paleoproterozoic(2.0 Ga) BIFs around the world. These characteristics of the Yuanjiacun BIF samples imply that the ancient ocean(2.3–2.1 Ga) was redox-stratified from oxic shallow water to deeper anoxic water. The specific redox conditions of the ancient ocean may be related to the GOE, which gave rise to the oxidation of Ce and Mn in the upper water, and to the presence of a Mn oxide shuttle in the ocean, resulting in varying REE patterns due to the precipitation and dissolution of this Mn oxide shuttle under different redox states. Therefore, the Yuanjiacun BIF appears to have formed near the redoxcline and lower-level reduced marine water.     

Long-period ground motion characteristic of the 1999 Jiji (Chi-Chi),Taiwan,main-shock and aftershocks

Introduction The study of attenuation relations for long-period ground motion is to meet the requirement of economy development. During the earthquakes such as the June 16, 1964 Niigata, Japan, M=7.5 earthquake, the March 24, 1977 Romania M=7.3 earthquake, the March 29, 1970 Gediz, Turkey, M=7.1 earthquake, the May 26, 1983 M=7.7 earthquake in the middle Japanese Sea, the September 19, 1985 Mexico M=8.1 earthquake, the September 16, 1994 M=7.3 earthquake in Tai- wan Strait, and the No…     

Comparison of the spatial distribution of ground motion between main shocks and strong aftershocks

Using the ground motion attenuation relation, we calculated and compared the effective peak acceleration (EPA) generated by main shocks and their strong aftershocks of 21 earthquake sequences with MS≥7 occurred in Chinese mainland and offing of China during 1966~2002. The result shows that EPA of strong aftershocks usually exceed that of main shock for 76.2% earthquake sequences and EPA of more than 50% strong aftershocks are greatly lar-ger than that of main shocks in large area, which suggests that it is necessary to take damage produced by strong aftershock into account in the probabilistic seismic hazard analysis and the seismic design.     

Short-term and imminent anomalies of earthquake of load and unload response ratio of the well level to earth tides

Ｓｈｏｒｔ┐ｔｅｒｍａｎｄｉｍｍｉｎｅｎｔａｎｏｍａｌｉｅｓｏｆｅａｒｔｈ┐ｑｕａｋｅｏｆｌｏａｄａｎｄｕｎｌｏａｄｒｅｓｐｏｎｓｅｒａｔｉｏｏｆｔｈｅｗｅｌｌｅｖｅｌｔｏｅａｒｔｈｔｉｄｅｓＺＨＡＯ－ＤＯＮＧＺＨＡＮＧ（张昭栋）１）ＸＵＥ－ＺＨＯ...     

Seasonal and Long-Term Changes in the Intensity of O2(b1Σ) and OH(X2Π) Airglow in the Mesopause Region

Geomagnetism and Aeronomy - Spectral observations of the mesopause airglow at the Zvenigorod Scientific Station have been used to obtain the midnight emission intensities of molecular oxygen...     

Ionization of the earth’s atmosphere by solar and galactic cosmic rays

A brief review of the research of atmospheric effects of cosmic rays is presented. Numerical models are discussed, that are capable to compute the cosmic ray induced ionization at a given location and time. Intercomparison of the models, as well as comparison with fragmentary direct measurements of the atmospheric ionization, validates their applicability for the entire atmosphere and the whole range of the solar activity level variations. The effect of sporadic solar energetic particle events is shown to be limited on the global scale, even for the most severe event, but can be very strong locally in polar regions, affecting the physical-chemical properties of the upper atmosphere, especially at high altitudes. Thus, a new methodology is presented to study cosmic ray induced ionization of the atmosphere in full detail using realistic numerical models calibrated to direct observations.     

The geochronology and origin of mantle sources for late cenozoic intraplate volcanism in the frontal part of the Arabian plate in the Karacadağ neovolcanic area of Turkey. Part 2. The results of geochemical and isotope (Sr-Nd-Pb) studies

A geochemical and isotope-geochemical (Sr-Nd-Pb) study has been carried out for the Karacada? neovolcanic area, which is situated within the frontal part of the Arabian plate. The obtained data and the results of petrological modeling show that the petrogenesis of parental magmas in the Karacada? neovolcanic area involved two compositionally different mantle sources; one consisted of garnet-bearing peridotites of the asthenosphere mantle and the other was spinel-bearing peridotites of the enriched subcontinental lithosphere mantle. During early stages in the evolution of the magmatic system, deep-seated asthenospheric magmas were ascending to the surface while intensively interacting with the melts that had been generated at upper mantle depths. The interaction gradually diminished, so that the later effusive rocks mostly have compositions that are similar to those of the primitive asthenospheric magmas. It is shown that a significant (up to 17–18 wt % of the mantle melt) assimilation of crustal material could take place only during the initial phases of the magmatism. Periodic replenishment of the magma chambers by primitive magmas, which resulted in an observable high degree of homogeneity in the composition of young effusive rocks, was also of importance in the petrogenesis of lavas during the evolution of volcanic activity.     

Professor Yu.D. Kalinin: The founder and first Editor-in-Chief of the Journal “Geomagnetism and Aeronomy” (Towards the Centenary of the Birth and to the 50th Anniversary of the Foundation of This Journal)

Information is given regarding the life, work, scientific research, and organizational activities of Professor Yu.D. Kalinin, the founder and the first editor-in-chief of the journal “Geomagnetism and Aeronomy.” The paper is devoted to the centenary of the birth of Yu.D. Kalinin and to the 50th anniversary of the beginning of the publication of the journal.     

The CO2 Discharge in the Boundary Fault Areas of the Sichuan-Yunnan Block and Its Sources

A large number of CO2 springs outcrop along the boundary faults of the Sichuan-Yunnan block and in their neighboring areas.These springs are of a roughly similar distribution as the epicenters of strong earthquakes since 1900.This similarity indicates that the CO2 discharges could be directly related to the modern seismic activity in that area.The evidences of stable carbon and oxygen isotopes indicate that an overwhelming majority of the CO2 released from modern active faults is derived from the deep earth crust.There are 2 main mechanisms of CO2 discharge.Modern active faults are able both to produce directly a lot of CO2 due to thermodynamic metamorphism and to provide passages for the CO2 constituent coming from the lower crust or upper mantle.By continuously monitoring the dynamic changes of CO2 discharges,it would be possible to obtain the information of earthquake precursors that reflect the physical and chemical changes of the earthquake sources.     

The Carbonate System of the Estuaries of the Syran and Ul’ban Rivers (Ul’banskii Bay,the Sea of Okhotsk) during Spring Flood

Water Resources - In the period of summer flood 2016, a number of chemical characteristics associated with carbon cycle were studied in the estuaries of the Syran and Ul’ban rivers in the...     

Effective relaxation time and viscosity of the earth inferred from the postseismic vertical deformations of the 1990 MS=7.0 Gonghe earthquake

Ｅｆｅｃｔｉｖｅｒｅｌａｘａｔｉｏｎｔｉｍｅａｎｄｖｉｓｃｏｓｉｔｙｏｆｔｈｅｅａｒｔｈｉｎｆｅｒｅｄｆｒｏｍｔｈｅｐｏｓｔｓｅｉｓｍｉｃｖｅｒｔｉｃａｌｄｅｆｏｒｍａｔｉｏｎｓｏｆｔｈｅ１９９０ＭＳ＝７．０ＧｏｎｇｈｅｅａｒｔｈｑｕａｋｅＱＩ...     

Performance of the Italian strong motion network during the 2009, L��Aquila seismic sequence (central Italy)

On April 6, 2009, the town of L’Aquila in the Abruzzo region (central Italy) was struck by a seismic event at 01:32 (UTC), of magnitude M_W = 6.3. The mainshock was followed by a long period of intense seismic activity and within seven days after the mainshock there were seven events of magnitude M_W ≥ 5 that occurred from April 6 to April 13. This long seismic sequence was characterized by a complex rupture mechanism that involved two major normal faults of the central Apennines: the Paganica and the Gorzano faults. The strong-motions of the mainshock were recorded by 64 stations of the Italian Strong-motion Network (RAN) operated by the National Civil Protection Department (DPC). Six stations of a local strong-motion array were working in NW L’Aquila suburb area. One of them, located at about 6 km from the Paganica fault surface tip-line, set up in trigger mode, recorded continuously for more than 20 min the mainshock and the aftershocks. Besides the mainshock, the RAN stations recorded in total 78 foreshocks and aftershocks of M_L ≥ 3.5, during the period from January to December 2009. The corresponding waveforms provide the most extensive digital strong ground motion data set ever recorded in Italy. Moreover, the 48 three-component observations of events of magnitude M_W ≥ 5, recorded at a distance less than 15 km from each of the major involved faults, provide a significant increasing of near-field records available for the Italian territory. Six days after the mainshock, the strong-motion dataset, referred to preliminary locations of the events with M_L ≥ 4.0, was made available on the DPC web site () and at the same time it was delivered to the ITACA database (). This dataset has been used by many authors in scientific papers and by engineers, geophysicists and geologists for professional technical works. In this paper, the present-day available strong-motion signals from the L’Aquila sequence and the performance of the Italian strong-motion network in terms of the number and quality of recorded data, the geometry and data transmission system are described. In addition the role of the temporary network that represents an extension of the permanent Italian strong-motion network, supporting the emergency response by civil protection authorities and improving the network coverage has been evaluated.     

Introduction to Acta Seismologica Sinica (The Bulletin of the Seismological Society of China)

Acta Seismologica Sinica (ASS) is a comprehensive publication on seismology by the Seismological Society of China. Its Honorary Editor-in-Chief is Academician QIN Xin-ling of Chinese Academy of Sciences (CAS) and Editor-in-Chief is Academician CHEN Yun-tai of the CAS. The first issue of Chinese edition of the ASS was published in 1979, and that of the English edition in 1988. From 1994 both of the English and the Chinese editions started to publish not only one-to-one correspon…