S33B-1307
Possible Mechanism of Earthquake Triggering due to Magnetostriction of Rocks in the Crust
In this study, stress changes due to magnetostriction of rocks in the crust are estimated. Many studies on electromagnetic phenomena caused by earthquakes have been carried out. However, we focused on the inverse effect, that is to say possibilities of earthquakes triggered by magnetic changes. Magnetostrictions are mechanical deformations of magnetic minerals accompanied by remanent or induced magnetization changes of them. They are characterized by magnetostriction constants, which are proportional coefficients between magnetization changes and mechanical deformations. In the calculation, only the magnetostriction for induced magnetization changes is considered. The magnetostriction constant of the crust is assumed to be 1×10- 5 ppm/nT, which is nearly the same as that for iron. Geomagnetic secular changes derived from the IGRF model for each 5 years are used as the surrounding field, and Coulomb Failure Function changes on a horizontal plain at the depth of 5 km are estimated. The result of the calculation shows that nearly 100 Pa/year forces can be caused by the magnetostriction in some area. Recent seismological studies suggest that small stress changes such as tidal forces can trigger earthquakes. Stress changes estimated from our calculations are about one order smaller than those caused by tidal forces. However, the geomagnetic field varies far more rapidly in times of magnetic storms. In such cases, stress accumulation rates due to the magnetostriction can be larger than those due to tidal forces. Therefore, the magnetostriction can be one of the mechanisms to trigger earthquakes, and this effect is worthy to be investigated in detail. We are now planning to investigate the relationship between the magnetostriction and the seismicity statistically with the mechanisms of earthquakes taking into account. Results of them will also be discussed at the meeting.
S33B-1308
Possibility Of The Electromagnetic Earthquake Precursor Source Localization
The existence of earthquake electromagnetic (EM) precursors is permanently discussed by the scientific community and there is no generally accepted opinion about their origin. A wide instrumentation array at California does not reveal any EM precursors of several recently occurred earthquakes (EQ), whereas rather simple set of magnetometers and/or electrometers in India, Greece, Japan very often reliably detected them. So, it appears that these precursors are very different in their peculiarities and they vary not only at diverse places but also for different times even at the same place. Apparently this depends on the specifics of geological formation in seismically active zones. This report is an attempt to explain some experimental facts with observed seismogenic ULF emissions. The possible phenomenological model of such diversity is discussed and some conditions of precursory signal detection are outlined. The approach to the determination of the EQ precursory EM signals source location is proposed based on multi-points observations of ULF electromagnetic signals in the monitored area. The main principle of the following data processing is based on the assumption that at relatively small distance between future EQ epicenter and observation points (no more than ~ 200 km), we are always in near zone of electromagnetic wave propagation what allows us to use as informative carrier signal amplitude only. This peculiarity can be used for enhancing the signal-to-noise ratio by processing simultaneously the synchronously collected signals at several observation points. One recent example of the EQ precursory EM signals detection in India, Koyna region, is discussed in details. It is shown that the obtained results fit rather well with previous theoretical modelling and the study of EM signal parameters (amplitude, polarization) allows us to simulate possible geological structure in the EQ epicenter which can generate the signals with observed parameters. In the conclusion, the critical requirements to the field observation system for electric and magnetic parameters monitoring in the seismically active regions are presented. The example of practical realization is given: the design features of the automated ULF observation system LEMI-30 with large dynamic range and satellite synchronization of signals sampling are discussed and the example of its practical realization is shown. This study is supported by STCU grant 3165.
S33B-1309
Observations Of The Low-Frequency Electric Field Fluctuations In The Ionosphere Over The Crust Faults
Based on the results of the satellite Dynamic Explorer-2 measurements it is established that the earth's crust large geological structure peculiarities influence on the ionosphere parameters outside of Auroral zone. It is characterized by occurrence in the ionosphere of areas of the sharp increasing of the low-frequency electric field in the range 1-500 kHz and the spectral density of the plasma fluctuations of the decameter scale; in these zones of the epithermal electrons penetrations are observed also. The specified effects do not depend on the seismic activity, local time, seasons and the level of the geomagnetic activity. Some hypotheses about the possible mechanisms of the lithosphere-ionosphere coupling, which are responsible for the found out effects, are stated.
S33B-1310
Studying Thermal Anomaly before Japan Earthquake with NCEP Data
Thermal anomaly before earthquake was widely studied with satellite data such as AVHRR and MODIS. A big disadvantage is that satellite thermal data can not penetrate thick clouds to retrieve surface temperature, and the distance between thermal anomaly and future epicenter is too far to estimate the possible epicenter. Here we first introduced NCEP Reanalysis data which is widely used in atmosphere research area, found the possible thermal anomalies before earthquakes, and in this research the distance between thermal anomaly and future epicenter is about 1degree. This method is easy, quick and low cost compared with the traditional geophysical method. According to this anomaly we can verify the possible epicenter within an reasonable spatial error of about 1 degree. If other geophysical method is combined with this method together, the false alarm may be reduced and the accuracy may be promoted.
S33B-1311
Ionosphere Responses to Large Earthquakes of Different Focal Mechanisms: Case Study of 1994, 2006 and 2007 Kuril Islands Earthquakes
Using GPS TEC measurements we studied ionosphere response to the Kuril Islands Earthquakes of 04 October 1994, 15 November 2006 and 13 January 2007 (all M>8.0). High spatial resolution of the Japanese dense GPS array (GEONET) allowed us to analyze dynamical characteristics of the propagation of the observed coseismic ionospheric disturbances (CID) in detail. The CID appeared ~10-15 minutes after the main shock and manifested themselves as 'positive' and 'negative' N-waves in TEC series with the amplitude of 0.6-1.0 TEC units. The CID were found to propagate with a spherically-similar wavefronts outward from the epicenters with the velocity of about of 800-1000 m/s that correspond to the sound speed at the height of the F-layer of the ionosphere. Then, at distances 500-600 km from the epicenter the propagation velocity increased to ~4 km/sec. This suggests that the TEC signals of the secondary acoustic waves excited by the Rayleigh surface waves became dominant as the subionospheric points went farther from the epicenter. Another important point is the dependence of the shape of TEC response on the type of fault that ruptured in the earthquake. The three earthquakes are of different types. The 2006 earthquake was a low-angle thrust event and the 2007 one was a normal fault event in the outer rise of the trench. Their coseismic movements are characterized as crustal uplift and subsidence, respectively. The 1994 earthquake occurred in the subducting Pacific Plate slab as a high-angle (~50 deg) reverse faulting resulting in both surface uplift and subsidence of comparable size. TEC response to a reverse faulting is known to show a 'positive' N-wave a typical compression-rarefaction wave, and this was the case for the 2006 event. On the other hand, normal faulting seems to cause a 'negative' N-wave, the negative TEC changes appear first, and this was the case for the 2007 outer rise earthquake. The TEC response to the October 1994 earthquake was a 'complex' one, i.e. it contains the two types of N-waves excited at the uplifted and subsided parts, and either one becomes dominant depending on the azimuth of subionospheric points relative to the epicenter.
S33B-1312
In Search for Thermal Precursors to Earthquakes in California Using MODIS Land Surface Temperature Data
We test claims that earthquakes are preceded by thermal anomalies by analyzing daily nighttime land surface temperatures (LSTs) derived from data collected by the MODIS (Moderate Resolution Imaging Spectroradiometer) instruments mounted on the Terra and Aqua satellites. Terra precedes Aqua by ~3 hours, so the LST difference between the two satellites provides an estimate of nighttime cooling/warming rates. The MODIS LST data used cover the period between 2000 and 2006 and are with ~1 km spatial resolution. They cover a 10ox10o tile including most of California, parts of neighboring Nevada and Arizona, and northern Mexico. Our focus is on quantifying various factors influencing the background variability of LSTs and estimating the uniqueness and statistical significance of any apparent LST anomalies. For this purpose, the LSTs and their Aqua-Terra differences are used to calculate parameters similar to the Robust Estimator of Thermal Infrared Anomalies (RETIRA) index, first described by Tramutoli (1998) and subsequently reported to show anomalously high values preceding a number of earthquakes (e.g., Tramutoli et al., 2005; Corrado et al., 2005; Genzano et al, 2007). We develop the RETIRA concept further in order to account better for meteorological and other effects on the LSTs. In particular, we quantify cloud edge effects and the effects of topography. The RETIRA index is computed for Terra LSTs, Aqua LSTs, and Aqua-Terra LST differences. We examine the relationship between M>4.5 earthquakes and anomalous RETIRA by generating movies of RETIRA time evolution. We also compare and test for statistical significance of the differences among four types of combined time periods - pre-seismic, during seismic clusters, post-seismic and seismically quiet periods. Although some statistically significant differences are established, they do not involve uniquely the pre-seismic periods and anomalies appear too ubiquitous during all types of periods to be useful for earthquake prediction. We will be further testing smaller areas around "hot spots" (Holliday and Rundle, 2005) and past earthquakes in California.
S33B-1313
Polarization Study of ELF-Emissions at Pre-earthquakes Time
ELF-emissions events below 100Hz from Aug. 24, 2003 to July 9, 2004 were observed at ELF station in Lulin Observatory of Taiwan (120o52' 25" E , 23o28' 07" N, 2862m) [\it Wang \it et \it al., 2005]. Various types of emission patterns are identified. Statistical analysis of these ELF emissions and earthquakes (M ≥ 5.0) occurred in Taiwan at the same observational period have shown that both the occurrence rates and numbers of these emissions significantly enhanced within several days prior to earthquakes. In this presentation, polarizations of these events signals as well as the propagation directions of associated waves will be investigated. The polarization changes prior to occurrences of earthquakes will be the primary focus to study to understand how they are associated with source regions of earthquakes. Reference Wang, K., Y. C. Wang, H. T. Su, and R. R. Hsu, Low-Latitude ELF Emissions Below 100Hz Observed in Taiwan (2005), Eos Trans. AGU, 86(52), Fall Meet. Suppl., Abstract SM41B-1180.
S33B-1314
Satellite Thermal Infrared Stress Field and Earthquake Prediction in Short-term and Imminent
It has been recognized that there is a temperature-increase anomaly before earthquake. Meteorological satellite based thermal infrared (IR) radiation in detecting ground surface temperature, thus anomaly, has its advantages, such as data accuracy, large areal coverage, a large amount of information and capability of capturing the time- space dynamic variation of the temperature - increase before earthquakes (Qiang Zuji et al., 1996). Earthquake precursors should enable a predicator to give the three elements of a future earthquake: location, magnitude and time, (Max Wyss, 1993) in which the method of thermal anomaly detection can provide all three elements. Practice is the only criterion to examine a truth. Chinese scientists in the satellite thermal-infrared earthquake-prediction group led by QIANG Zuji and DIAN Changgong have carried on practicing short and imminent earthquake prediction since 1990. Over the years we have made steady and exciting progress. During the 11 years from 1990 to 2000, we made 119 predictions. of which 58 were valid and 15 were false alarms. The success rate of those predictions increases from 24% during period of 1990-1995, to 46% in 1996, 53% in 1997, 76% in 1998, to 80% in 1999 and 2000, summarized by Wang (2005). The satellite infrared detected thermal stress field is a reflection of the earth's crust stress condition when rock stress increases the spot along the stress to produce micro fissures in rock. Therefore, hot plane and line that have the closet relation with the stress condition and the rock faulted structure can demonstrate the compression stress direction. The thermal stress types have been recognized over years include isolated X shear structure, en echelon, single arm form, the string of beads shape, ~{!J~} type, rotation shear ellipse, and the advancement rotation shear ellipse (Wu Li-xin, Liu Shan-jun, 2006,Qiang Zuji et al 1991,1993,1995,1996,1997,2001)
S33B-1315
Discrimination of the earthquake-origin microwave emission from the data of the spaceborne radiometer
Formerly, we found the microwave emission during rock crash in a laboratory for the first time in the world, and calibrated the emitted power. The detected signal is a sequence of pulses which include microwaves at the selected frequency bands of 300MHz, 2GHz and 22GHz. This fact suggested another means to detect an earthquake which is associated with rock crash or plate slip. For this purpose, we have analyzed the data obtained by the microwave radiometer, AMSR-E loaded on the satellite Aqua. Generally, since a microwave emission observed by AMSR-E is affected by various factors (e.g., emission of the earth's surface and emission, absorption and scattering of the atmosphere), we developed some analysis techniques first. Then, we have successfully extracted features observed only at the earthquake occurrence by these techniques. This earthquake was occurred at Morocco in 2004. Since the depth of the seismic center was shallower and the magnitude was larger, we have specifically focused on analysis of this earthquake. This presentation first presents the estimation of the received power by a receiver aboard a satellite. Then, the data obtained by AMSR-E are described including the disturbances or ambiguity of the data. The techniques to extract microwave signatures out of disturbances are given. Finally, an example of the data analysis is explained in the case of Morocco earthquake to show distinct emission of microwaves in relation with geological features.
S33B-1316
Observation of electromagnetic signals in an underground observation room
We constructed an underground room to observe electromagnetic signals in the terrestrial environment associated with earthquake in 2004. Underground observation has an advantage; it is hardly influenced by the meteorological conditions and artificial noises. The observation room locates in the middle of a drift that penetrates the tuff and andesite bedrock, in Miyagi Prefecture, northeast Japan. This room is 1.5 km deep from the pithead and 70 m below the ground surface, and the room size is about 15 m x 12 m area with about 2.5 m height. In the observation room, we have observed the vertical electrostatic field, geomagnetic field, seismic wave, air ion concentration and static electricity on the wall, as well as the air pressure, air temperature and humidity. The observed data are stored in recorders with a GPS time stamp system, so that the time accuracy of 1 ms is assured. As a result, the normal signal levels of air ion concentration exhibit daily and seasonal changes slightly that can be explained by the air movement in the drift system and the earth tide effects. In addition, we often got anomalous signals when seismic waves arrived. In this presentation, we report the details of the underground observation system and some of the anomalous signals.
S33B-1317
Positive electrification on rock surface in field observation and laboratory experiments
We have observed the vertical electrostatic field using a large plate antenna under ground. This observatory space (12 m x 15 m x 2.4 m) locates middle of a mine-gallery penetrating tuff and andesite bedrock in northeast Japan. This plate antenna (4 m x 4 m) is placed 1.2 m above the floor with insulator pillars and connected to the floor through a recorder with 1-MØmega impedance. When seismic waves reached the room floor, the antenna often detected the electric field upwards. One of the potential mechanisms is the positive electrification of the floor. Here, we inspected such electrification using air-dried brocks of igneous rocks in laboratory. As results, the rock samples that were pressed partially also showed the positive electrification on the surface of the unstressed volume. Because the rock samples were air-dried and normally good insulators against electrons, the assumption of positive holes is reasonable to explain the electrification. They can be activated from the deformation of positive hole pairs that are populous lattice defects also known as peroxy bonds. The activated positive holes in the stressed volume can spread away into the unstreesed volume through the mineralfs valence band network. In case of the underground detection, the seismic wave would activate positive holes near the underground room floor.
S33B-1318
A preliminary study on correlation between thermal infrared radiation of land surface and borehole strain
To predict earthquake by using thermal infrared radiation (TIR) is attended widely in recent years although there are still some basic problems to be solved. In fact, earthquake is only one kind of fault activity. Not all fault motions could generate earthquakes. Therefore the shift of research focus from seeking seismic precursors to monitoring processes of current tectonic activity through satellite remote sensing will provide more definite physical evidence and more chances. However, one of the problems that we have to know is how to obtain physical relation between TIR and tectonic deformation. In order to construct physical relation between TIR and tectonic deformation, some works on theoretic analyses and results of borehole strain are accomplished: Firstly, theoretic relation between volume strain and temperature is built up according to tensor decomposition with thermodynamics and elastic strain theory. As for elastic body, there exists definite linear relation between volume strain increment(Δθ) and temperature increment(Δ T): Δ T=α TΔθ, where α is constant and T is initial temperature. Namely, TIR produced by volume change is positive correlated with volume strain increment. Secondly, correlation between land surface TIR and borehole strain is analyzed by taking an example for borehole strain data more than 10 years from Kuerle and Shuimogou stations in Xing Jiang, located nearby Tiemenguan fault and Bogda fault in Tianshan area, respectively. Result indicates that strains are accorded with TIR when volume strain is dominant. When deviatoric strain is dominant, strain of one direction is positively related with TIR while another direction is negative. Consequently, tensor decomposition is helpful to analyze correlation between thermal infrared radiation and crust deformation if strain tensor is decomposed into spherical tensor related with volume strain and deviatoric tensor related with shape change. In sum, there exists definite physical correlation between TIR and crust deformation, which would provide a certain theoretic background for studying current tectonic activity with thermal infrared remote sensing.
S33B-1319
Sources of EMF in Near Earth and Planetary Environments
The realization that extensive electrical activates occur in and above the troposphere, extending to the ionosphere and ultimately coupling to the magnetosphere have raised the theoretical and experimental questions regarding the sources of EMF which create the observed effects. The current work has identified 17 Local Electrical Batteries (LEBs), which provide the electrical EMF that can be linked to the observed effects of Sprites, Elves, etc. and which additionally are shown to directly power the tropospheric storm systems and counter-rotating jet streams (rotating in the easterly direction in the northern and southern latitudes and westerly near the equator). The path of these sources of EMF can be followed from the passing solar wind through "tunnels" that end in electrical currents that pass into the atmosphere via the ionosphere to storm cloud systems in the lower atmosphere. These are the sources of electrical energy that power the severe lower atmospheric storm systems such as hurricanes and tornadoes. The model for these storm systems is included. The connection is made theoretically with the solar wind that drives the 17 identified LEBs. The dynamics of small dust particles including water molecules and droplets in the LEB environment shows that these particles become electrically charged and their Debye shielding takes on a new form which is extended from that of the neutral environment typically considered in previous theoretical models. An attempt is made to solve the fundamental problem of the source of energy that drives these systems. Previous meteorological models considered that the energy sources for lightning and other energetic phenomenon came from within the storm systems. The current work shows that the original sources of EMF are actually in the passing solar wind. Additionally, the effects of moons and their positions relative to the planet and solar wind are shown to contribute to the overall discharge phenomenon. A connection is made between these energy sources and earth quake and volcanic "trigger" mechanisms.
S33B-1320
Data Exploration Study of Atmospheric TIR Signals Associated with Tectonic Faulting and Earthquake Processes
This paper extends previous research to explore statistically the relationship between earthquake processes and atmospheric thermal anomalies in order to study the phenomena and their significance. Specifically, we analyzed and compared long time series atmospheric thermal field data over California to create statistical summaries of the correlation of thermal variations with earthquake events (both spatially and temporally) in terms of average plots, upper and lower standard deviations and anomalies. Our data exploration methodology is based of an analysis of: (1) Outgoing long wave radiation (OLR) observed by the AVHRR sensor on NOAA POES series satellites (data provided by the NOAA Climate Prediction Center); and (2) seismic activity in the study site as recorded by the USGS. We perform analysis of earth radiation on the atmosphere (daytime and nighttime) and OLR by analyzing monthly and daily averages around the area of major tectonic faulting and earthquake epicenters. Both "normal" and "anomalous" states of the satellite and ground segments were defined for 27 years of data, for both monthly and daily averages. Preliminary results show correlation of the OLR and tectonic activity during the time of the major earthquake occurrence, and existence of false alarms (positive /negative) for the period of data analysis. The outcome of this study has potential to contribute in two major areas of interests: (i) performance of a comprehensive statistical analysis of the correlation between transient atmospheric signatures and (ii) development of a methodology to evaluate the requirements of TIR signal measurement for future observation system development associated with tectonic faulting