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1.
This paper discusses observations of varying tectonic forces in the Kamchatka volcanic belt around the Avacha Bay using a
geomechanical sensor. These observations are used to infer an estimate of the earthquake hazard to Petropavlovsk-Kamchatskii. 相似文献
2.
S. E. Smirnov G. A. Mikhailova Yu. M. Mikhailov O. V. Kapustina 《Geomagnetism and Aeronomy》2017,57(5):610-617
The diurnal variations in electrical (quasistatic electric field and electrical conductivity) and meteorological (temperature, pressure, relative humidity of the atmosphere, and wind speed) parameters, measured simultaneously before strong earthquakes in Kamchatka region (November 15, 2006, М = 8.3; January 13, 2007, М = 8.1; January 30, 2016, М = 7.2), are studied for the first time in detail. It is found that a successively anomalous increase in temperature, despite the negative regular trend in these winter months, was observed in the period of six–seven days before the occurrences of earthquakes. An anomalous temperature increase led to the formation of “winter thunderstorm” conditions in the near-surface atmosphere of Kamchatka region, which was manifested in the appearance of an anomalous, type 2 electrical signal, the amplification of and intensive variations in electrical conductivity, heavy precipitation (snow showers), high relative humidity of air, storm winds, and pressure changes. With the weak flow of natural heat radiation in this season, the observed dynamics of electric and meteorological processes can likely be explained by the appearance of an additional heat source of seismic nature. 相似文献
3.
Approaches to the estimation of lateral heterogeneity of the upper mantle by electromagnetic methods
V. V. Plotkin A. Yu. Belinskaya P. A. Gavrysh 《Izvestiya Physics of the Solid Earth》2007,43(3):245-250
The paper addresses the construction of maps showing lateral distributions of the apparent electrical conductivity in various time periods from data of the worldwide network of observatories. The lateral distribution of the apparent conductivity of the Earth is determined by a self-consistent estimation of variations in three components of the geomagnetic field recorded at all stations. The results of processing of data on daily geomagnetic variations observed at the worldwide network in 1964–1968 are presented. 相似文献
4.
针对高邮-宝应4.9级地震发生前后附近地区未发生其它中等以上地震、地震事件孤立及周边地磁台站分布较密有利于研究地震地磁异常时空特征的特点,较为系统地分析总结了该地震发生前后地磁谐波振幅比的变化特征,研究结果进一步验证了目前对地磁谐波振幅比异常特征的认识,即地磁谐波振幅比异常特征表现出与地电阻率类似的下降-转折-恢复上升的异常变化过程,地震一般发生在异常转折或恢复上升过程中,距震中较近的台站会出现不同步现象——南北向与东西向的不同步以及长短周期的不同步。 相似文献
5.
本文是“地震的感应磁效应（一）--三维电磁感应的数值理论”一文的继续。首先从理论和实际计算两个方面证明了三维电磁感应数值方程解的唯一性、收敛性和稳定性,从而充实了作为研究地壳、上地幔电性结构横向不均匀性理论基础的“三维数值方法”。作为这一理论方法的实际应用,文中对不同源场周期和具有不同埋藏深度的三维电导率异常体进行了模拟计算,以研究地震感应磁效应的大小、空间分布特征和频率特性。模拟计算结果表明,对于周期从数秒到数分钟的地磁短周期变化,若电导率异常体的线度与5至7级地震的震源体积大体相当,其电导率较原背景电导率高近一个量级,其感应磁效应主要特征为:在异常体正上方,地面磁场的水平分量变化最大,相对变化量约30％;在异常体于源场方向一致的两侧,垂直分量变化最大,相对变化量约40-50％。因此,观测短周期地磁场的异常变化,有可能是监测地震孕育过程地下电性变化的一种试验途径。但由于上述异常强度在空间上衰减迅速,所以观测必须接近震源区,这对测点的选择是个不利的因素。 相似文献
6.
地磁月均值的长期变化结果表明，1994年台湾海峡7．3级地震前4年，泉州台与仑坪台的X和Z分量均出现异常，X分量呈现负异常，Z分量呈现正异常，异常幅度达20－30nT.另外，地震前一年半，泉州台与通海台的视深比或仑坪台与通海台的视深比（周期为24h)都出现过先降后升的异常变化。 相似文献
7.
Yu. M. Mikhailov G. A. Mikhailova O. V. Kapustina G. I. Druzhin S. E. Smirnov 《Geomagnetism and Aeronomy》2006,46(6):796-808
Simultaneous records of the diurnal variations in the quasistatic electric field in the near-Earth atmosphere, fluxes of discrete electromagnetic pulses in the VLF band, source azimuths, narrowband filter output emission intensity at frequencies of 4.65 and 5.3 kHz, and time forms and spectra of VLF pulses have been analyzed. The anomalous behavior of these parameters in October 2002 and August 2004 with different time delay was accompanied by earthquakes near the southeastern coast of Kamchatka at distances of 250–400 km from the registration points. Based on the results of a fine frequency-time analysis of the broadband records of VLF signals, it has been indicated for the first time that discrete electromagnetic pulses observed in anomalous fluxes before earthquakes were signals of local thunderstorm processes. 相似文献
8.
—The 1989 M s = 7.1 Loma Prieta earthquake was preceded for 12 days by what have been claimed as precursory ultra-low-frequency (ULF) magnetic noise anomalies ten times background, and by a very high peak up to 100 times background just 3 hours before the earthquake. We propose that these anomalous fields could have been due to the formation of a long thin highly-conductive region along the earthquake fault, which magnified the external electromagnetic waves incident on the earth’s surface. We use a simplified quantitative model, assuming a highly-conductive elliptic cylinder embedded in a layered resistivity structure, which we base on independent magnetotelluric measurements. The magnetic-field anomaly observed 3 hours before the main shock can be modeled by assuming an elliptic conductor extending from the surface to the hypocenter with a conductivity of 5 S · m?1. Our computed anomaly matches the observed anomaly to within a deviation of 35% over an observed frequency range of over 2 orders of magnitude, over which the measured anomaly varies from only about twice background (at 5 Hz) to about 100 times background (at 0.01 Hz). In addition, other anomalies recorded up to 12 days before the earthquake, can be modeled in detail by varying only the size of the elliptic conductor.¶We show that such an increase in conductivity could be caused by a precursory reorganization of the geometry of fluid-filled porosity in the fault-zone, which we call a dilatant-conductive effect. The extreme observed magnetic anomalies can be modeled using the high fault-zone porosity (c. 10%) and fluid conductivity (equivalent to 2 M NaCl) implied by other workers’ magneto-telluric measurements, but without requiring the large-scale precursory fluid flow characteristic of other published models for the magnetic-field precursors. 相似文献
9.
Variations of geomagnetic components X, Y, and Z recorded in 19 Intermagnet European observatories in 2004 were analysed. The original data from all observatories were preliminarily
processed. In the first step, periods longer than three hours were filtered out. In the second step, variations of vertical
geomagnetic component Z were separated into external and internal parts. We introduced a non-dimensional index η defined as the square root of a ratio of the energy of the external part of the vertical component to that of the horizontal
components. Maps of the surface distribution of a new magnetic index η for the area of Europe at selected time periods were created, and their time changes are presented. The time changes of η for selected observatories are also shown. Moreover, we discuss a very interesting phenomenon we discovered, that has never
been described in geophysical literature. Namely, in the recordings of all the observatories we noticed the presence of very
regular variations, observed almost exclusively in the vertical component Z, which is quite unusual. These regular variations occur in the form of sinusoidal “wave packets”. The amplitudes of these
variations do not depend on the geomagnetic latitude and appear in the records of all the observatories we analyzed. They
occur in quiet days, which suggests that their source is in the ionosphere. 相似文献
10.
L. B. Slavina N. B. Pivovarova V. I. Levina 《Journal of Volcanology and Seismology》2009,3(5):326-337
We present computations of 3D P-wave velocity field for the segment of the Benioff zone of Kamchatka between 51.5° N to Avacha Bay to Cape Shipunskii to
Kronotskii Bay. P-wave travel times for regional earthquakes were used to compute and construct 3D models of the velocity field for this segment
of the Benioff zone. We examined the velocity structure to interpret it in conjunction with neotectonic morphostructures.
The computations showed a complex structure of the field and the presence of inhomogeneities, both along and across the Benioff
zone. Of special interest are the results for the Avacha and Kronotskii basins, where high velocity masses are unusually shallow
beneath the low velocity layers in the top of the earth section. This creates high-gradient zones that can possibly generate
large earthquakes. 相似文献
11.
日本鹿屋台地磁静日变化中可能存在的震磁效应 总被引：2，自引：1，他引：1
１９９６年１０月１９日日本九州宫崎（Ｍｉｙａｚａｋｉ）发生７．１级地城,城中距鹿层地磁台约９０ｋｍ。利用Ｓｑ单台Ｚ／Ｈ法分析了１９８１～１９９８年鹿屋台与佘山台的资料,再研究两台视深比随时间的变化,结果表明,地震前一年多时间内视深化出现较大的负异常,同期的佘山与武汉台的视深比曲线未出现类似的异现象。因此,上述异常可能与宫崎地震有关。 相似文献
12.
Metasomatized harzburgite xenoliths from Avacha volcano as fragments of mantle wedge of the Kamchatka arc: Implication for the metasomatic agent 总被引：6，自引：0，他引：6
Abstract Abundant peridotite xenoliths have been found in pyroclasitics of Avacha (Avachinsky) volcano, the south Kamchatka arc, Russia. They are mostly refractory harzburgite with or without clinopyroxene: the Fo of olivine and Cr/(Cr + Al) atomic ratio of spinel range from 91 to 92 and from 0.5 to 0.7, respectively. They are metasomatized to various extents, and the metasomatic orthopyroxene has been formed at the expense of olivine. The metasomatic orthopyroxene, free of deformation and exsolution, is characterized by low contents of CaO and Cr2 O3 . The complicated way of replacement possibly indicates low viscosity of the metasomatic agent, namely hydrous fluids released from the relatively cool slab beneath the south Kamchatka arc. This is a good contrast to the north Kamchatka arc, where the slab has been hot enough to provide slab-derived melts. High content of total orthopyroxene, 40 vol% on average, in metasomatized harzburgite from Avacha suggests silica enrichment of the mantle wedge, and is equivalent to some subcratonic harzburgite. Some subcratonic harzburgites therefore could have been formed by transportation of subarc metasomatized peridotites to a deeper part of the upper mantle. 相似文献
13.
陈伯舫 《地震学报(英文版)》1994,7(3):457-464
ＩｎｖｅｓｔｉｇａｔｉｏｎｓｏｆｔｈｅｓｅｉｓｍｏｍａｇｎｅｔｉｃｅｆｆｅｃｔｉｎｔｈｅｇｅｏｍａｇｎｅｔｉｃｄｉｕｒｎａｌｖａｒｉａｔｉｏｎｓＰｏ－ＦａｎｇＣＨＥＮ（陈伯舫）（ＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃｓａｎｄＤｅｐａｒｔｍｅｎｔｏｆＧｅ... 相似文献
14.
IntroductionGenerallyspeaking,thedataofprecursorymonitoringwhichmightbeassociatedwiththepreparationofthefutureearthquakes,couldberepresentedbyatimeseries.There,however,wouldbenotonlyanomalouschangesassociatedwiththeearthquakeoccurrences,butalsosomechangeswhichwouldberelatedtosourcesotherthantheearthquakepreparation,eitherknownorunknowntotheinvestigatorsandbecalledas(thechangesfromnon-earthquakeeffects(,inthetimeseries,inpractice,tillnow.ItistosaythatthetimeseriesF(t)showingthetemporalchangesof… 相似文献
15.
I. A. Shirokov N. A. Zharinov B. P. Pertsev K. M. Anokhina 《Journal of Volcanology and Seismology》2009,3(6):405-413
We consider the results of ground tilt observations in the area of Klyuchevskoi Volcano, Kamchatka at the Klyuchi and Apakhonchich
stations using photoelectric tiltmeters. An anomalous tilt was recorded during a period of increased activity in the summit
crater of Klyuchevskoi Volcano in November 1979. In January and February 1980 three more cases of anomalous tilting before
the volcano’s active periods were observed. The tilts exhibit some common kinematic features that are quite consistent with
the activity periods. Various disturbing influences were estimated as affecting the observations of tilts related to seismic
and volcanic events. For the first time in Kamchatka, the parameters of the five principal elastic-tide waves have been determined.
Sea tides exerted an indirect effect on the amplitude factors γ(M2) on the E-W component at both sites to decrease them relative
to the global value, γ(M2) = 0.7. We investigated the influence of sea tides on the elastic solid earth tide along the Trans-Kamchatka
and Kola traverses. The observed and theoretical γ(M2) factors at both traverses situated in different geodynamic areas are
in approximate agreement. 相似文献
16.
根据捷克和斯洛伐克电磁台站的数据 ,得到波西米亚块体地壳和上地幔的电阻率分布模型。估计电阻率时特别使用了短周期和长周期的电磁数据以及用连续谱方法对固定台站数据的分析结果。根据欧洲地磁感应矢量分布绘出了显著的地电不均匀带的地图 ,将波西米亚块体的视电阻率与中欧有关台站的感应标量长度与W1响应做了比较 ,并根据电阻率 /深度图估计了电导率范围 ,该图与替代性理想导体反演相对应 相似文献
17.
O. A. Girina S. V. Ushakov N. A. Malik A. G. Manevich D. V. Mel’nikov A. A. Nuzhdaev Yu. V. Demyanchuk L. V. Kotenko 《Journal of Volcanology and Seismology》2009,3(1):1-17
Eight strong eruptions of four Kamchatka volcanoes (Bezymyannyi, Klyuchevskoi, Shiveluch, and Karymskii) and Chikurachki Volcano on Paramushir Island, North Kurils took place in 2007. In addition, an explosive event occurred on Mutnovskii Volcano and increased fumarole activity was recorded on Avacha and Gorelyi volcanoes in Kamchatka and Ebeko Volcano on Paramushir Island, North Kurils. Thanks to close cooperation with colleagues involved in the Kamchatkan Volcanic Eruption Response Team (KVERT) project from the Elizovo Airport Meteorological Center and volcanic ash advisory centers in Tokyo, Anchorage, and Washington (Tokyo VAAC, Anchorage VAAC, and Washington VAAC), all necessary precautions were taken for flight safety near Kamchatka. 相似文献
18.
The manner in which the dynamics of geoelectric earth inhomogeneities can be studied using receiving lines oriented in different directions at a single site is considered. It is shown that the presence of a local geoelectric inhomogeneity allows monitoring the state of electric conductivity in the earth by observation of the telluric tensor. We quote results from long-continued monitoring of the electrotelluric tensor in Kamchatka. The tensor’s behavior showed an appreciable anomaly, which may have been related to great (magnitude 8.2 and 8.3) earthquakes in the Kuril-Kamchatka region. 相似文献
19.
Investigation of the electrical conductivity beneath China using geomagnetic spatial gradient method
Ｉｎｖｅｓｔｉｇａｔｉｏｎｏｆｔｈｅｅｌｅｃｔｒｉｃａｌｃｏｎｄｕｃｔｉｖｉｔｙｂｅ┐ｎｅａｔｈＣｈｉｎａｕｓｉｎｇｇｅｏｍａｇｎｅｔｉｃｓｐａｔｉａｌｇｒａｄｉ┐ｅｎｔｍｅｔｈｏｄＧＵＯ－ＨＵＡＦＡＮ（范国华）ＴＯＮＧ－ＱＩＹＡＯ（姚同起）ＺＵＯ... 相似文献
20.
The seismic waves excited by the M
w
7.6 Olyutorskii earthquake that occurred on April 20, 2006 in the Koryak Upland gave rise to water-level changes in five
wells situated in continental areas of Kamchatka at hypocentral distances of 750–1150 km. We describe the effects due to seismic
waves, as well as the water-level anomalies for February–April 2006 before the earthquake. We used an original technique for
the processing of water-level records based on the study of barometric and tidal water-level responses in order to estimate
the volume strain in water-saturated rocks during synchronous level variations at two wells. We discuss possible mechanisms
for producing anomalous water-level changes due to elastic deformation of monitored groundwater reservoirs and to crack dilatancy
in the water-saturated rocks. 相似文献