Observation and research on ULF and VLF seismo－electromagnetic radiation

ＯｂｓｅｒｖａｔｉｏｎａｎｄｒｅｓｅａｒｃｈｏｎＵＬＦａｎｄＶＬＦｓｅｉｓｍｏ－ｅｌｅｃｔｒｏｍａｇｎｅｔｉｃｒａｄｉａｔｉｏｎＪＩＡ－ＺＨＩＹＵＡＮ（袁家治）；ＫｏｚｏＴａｋａｈａｓｈｉ；ＳＨＵ－ＱＩＮＧＱＩＡＮ（钱书清），ＹｏｋｉｏＦｕｊｉｎａｗ...     

Accurate determination of calibration factor for tidal gravity observation of a GWR-superconducting gravimeter

Introduction The superconducting gravimeters (SGs) are widely used to observe the change in temporal and spatial gravity field by many countries along the world, considering their characteristics as of the high-precision, good continuity and stability. By using the temporal variation of the tidal grav-ity obtained from the global network of SGs, the Global Geophysics Project (GGP) aims at some hot problems in geophysics and geodynamics (SUN, HSU, 1997). The original observations of the c…     

The application of the high-frequency electromagnetic sounding method in the exploration of underground thermal water

High-frequency electromagnetic sounding is an electromagnetic exploration method using the natural high-frequency electromagnetic field as a field source. It has higher resolution and greater depth penetration than the direct current method and is especially fit for geothermal energy exploration and low- and mid-level groundwater detection. We introduce a successful application of high-frequency electromagnetic sounding for evaluating geothermal water resources. The high frequency electromagnetic system （MT-USA with a frequency range from 10 KHz to 1 Hz） is first applied to sample field data from China. A remote reference station is used to assure sampled data quality. We then perform 2D inversion image processing with the electrical method data. The results basically indicate the spatial distribution of underground geothermal water and provide favorable clues to finding the sources of the subsurface geothermal water in this area.     

The influencing factors and mechanisms of the electromagnetic radiation during rock fracture

ＴｈｅｉｎｆｌｕｅｎｃｉｎｇｆａｃｔｏｒｓａｎｄｍｅｃｈａｎｉｓｍｓｏｆｔｈｅｅｌｅｃｔｒｏｍａｇｎｅｔｉｃｒａｄｉａｔｉｏｎｄｕｒｉｎｇｒｏｃｋｆｒａｃｔｕｒｅＹＵ－ＺＨＯＮＬＩＵ１）（刘煜洲）ＹＩＮＬＩＵ１）（刘因）ＹＩＮ－ＳＨＥＮＧＷＡＮＧ２...     

The quasi－static solutions of two kinds of the thermo－elastic problem and the time spacedistributionfeatureoftheseismicprecursorfields

Ｔｈｅｑｕａｓｉ┐ｓｔａｔｉｃｓｏｌｕｔｉｏｎｓｏｆｔｗｏｋｉｎｄｓｏｆｔｈｅｔｈｅｒｍｏ┐ｅｌａｓｔｉｃｐｒｏｂｌｅｍａｎｄｔｈｅｔｉｍｅｓｐａｃｅｄｉｓｔｒｉｂｕｔｉｏｎｆｅａｔｕｒｅｏｆｔｈｅｓｅｉｓｍｉｃｐｒｅｃｕｒｓｏｒｆｉｅｌｄｓＹＯＮ...     

Seismicity of the Baikal rift zone for the digital recording period of earthquake observation (2001–2006)

Some characteristics of the seismic regime of the Baikal rift zone for the analogue (1960–2000) and digital (2001–2006) registration modes are considered. It was ascertained that the general number of seismic events recorded by digital equipment increased by two times in comparison with the analogue observation period and the catalog completeness level was lowered to K _P = 7.0 as well. The focal mechanisms of 110 earth-quakes with K _P ≥ 8.0 were examined. The overwhelming majority of them during 2001–2006 were due to normal faulting and normal faulting with strike-slip components. Special attention was given to study of the strong events (K _P ≥ 13.5 and MPSP ≥ 4.7), whose focal solutions reveal the regional stress field.     

Study of calibration function for surface wave magnitude of DK1 seismographs

ＳｔｕｄｙｏｆｃａｌｉｂｒａｔｉｏｎｆｕｎｃｔｉｏｎｆｏｒｓｕｒｆａｃｅｗａｖｅｍａｇｎｉｔｕｄｅｏｆＤＫ１ｓｅｉｓｍｏｇｒａｐｈｓＦＥＮＧＸＵＥ（薛峰）ＹＯＮＧＺＨＡＯ（赵永）ＣｅｎｔｅｒｆｏｒＡｎａｌｙｓｉｓａｎｄＰｒｅｄｉｃｔｉｏｎ，Ｓｔａｔ...     

The Mathematic Models of the Kalman Filtering for Across-Fault Measurement

This paper makes a probe into the application of the Kalman filtering method to the data processing of across-fault measurements.On the basis of statistical regression,the mathematic and stochastic models of filtration are established by combining the regression method with Kalman filtering.In the filtering computation,not only the randomness of fault movements but also the time-dependent variation of environmental effects have been taken into consideration.By use of the adaptive filtering method,an estimation of the dynamic noise variance matrix is obtained through iteration.Models for one measuring line(leveling line or baseline),two measuring lines(both leveling lines or both baselines)and four measuring lines(two leveling lines and two baselines)are derived and established systematically.By means of these models,the data of across-fault measurements can be processed dynamically in real-time to provide the filtered values of height difference between benchmarks or baseline length at different time in     

Estimation of the temperature in the Earth’s interior from surface measurements of the electromagnetic field

The possibility of contactless remote estimation of the temperature in the Earth’s interior from surface magnetotelluric (MT) measurements is examined. The neuronet analysis of MT and temperature measurements in the Bishkek geodynamic research area (the Northern Tien Shan) showed that a contactless electromagnetic geothermometer can in principle be realized. An optimal method including MT measurements and treatment of available thermograms is developed. The method minimizes uncertainties of the remote temperature estimation. The use of six to eight thermograms for calibration of electromagnetic data is shown to provide a 12% relative error of prediction, and a priori geological information available for the region under study can reduce this error. Areas of practical application of a contactless electromagnetic geothermometer are outlined.     

Experimental study of ultralong wave band for electro－magnetic signals and acoustic emission during rock fracture

Ｅｘｐｅｒｉｍｅｎｔａｌ　ｓｔｕｄｙ　ｏｆ　ｕｌｔｒａｌｏｎｇ　ｗａｖｅ　ｂａｎｄ　ｆｏｒ　ｅｌｅｃｔｒｏ－ｍａｇｎｅｔｉｃ　ｓｉｇｎａｌｓ　ａｎｄ　ａｃｏｕｓｔｉｃ　ｅｍｉｓｓｉｏｎ　ｄｕｒｉｎｇ　ｒｏｃｋ　ｆｒａｃｔｕｒｅ（曹惠馨）（钱书清）（吕...     

The Rigid body of Paleo－continent in the crust of Taiwan and the recent plate movement

ＴｈｅＲｉｇｉｄｂｏｄｙｏｆＰａｌｅｏ－ｃｏｎｔｉｎｅｎｔｉｎｔｈｅｃｒｕｓｔｏｆＴａｉｗａｎａｎｄｔｈｅｒｅｃｅｎｔｐｌａｔｅｍｏｖｅｍｅｎｔＧａｎｇ－ＸｉａＬＩＵ（刘光夏），Ｗｅｎ－ＪｕｎＺＨＡＯ（赵文俊）Ｗｅｎ－ＪｕＲＥＮ（任文菊）ａｎｄＸｉｕ...     

The Akp-Btk value method and the results for the retrieval of the parameters of the Earth's free core nutation

The rotation of the Earth's liquid core creates the Nearly Diurnal Free Wobble (NDFW). It is one of the problems of researching the Earth's liquid core for us to retrieve the parameters of the Earth's Free Core Nutation (FCN), from the Earth's liquid core resonance of gravity tide waves on the diurnal frequency band. Since 1987, some scientists in many different countries have come to calculate the parameters of FCN by using the observational data of gravity tide waves on the diurnal frequency band. They basically followed the Stacking method, which needed five diurnal waves for the resolution. In this paper, authors introduced the Akp-Btk value method with clearly geometrical meaning as a new method, which only requires three very high signal-noise-ratio waves O1, K1 and P1 for the resolution. Authors chose the observational data of the three superconducting gravimeter stations respectively located in Cantley of Canada, Wuhan of China and Brussels of Belgium, to compute the parameters of FCN. It was the first time that the observational results of the parameters of FCN obtained from gravitational tide were in accord with the parameters of FCN gained from VLBI since 1987.     

The fine velocity structure of sediment－base－ment layer in the Three－GorgesRegionoftheChangjiangRiver（YangtzeRiver）

Ｔｈｅｆｉｎｅｖｅｌｏｃｉｔｙｓｔｒｕｃｔｕｒｅｏｆｓｅｄｉｍｅｎｔ┐ｂａｓｅ┐ｍｅｎｔｌａｙｅｒｉｎｔｈｅＴｈｒｅｅ┐ＧｏｒｇｅｓＲｅｇｉｏｎｏｆｔｈｅＣｈａｎｇｊｉａｎｇＲｉｖｅｒ（ＹａｎｇｔｚｅＲｉｖｅｒ）ＨＯＮＧ－ＸＩＡＮＧＨＵ（胡鸿翔），...     

The spatial characteristic of the short－term and imminent anomalies of waterradonbe┐foreearthquakeinthemainlandofChina

Ｔｈｅｓｐａｔｉａｌｃｈａｒａｃｔｅｒｉｓｔｉｃｏｆｔｈｅｓｈｏｒｔ┐ｔｅｒｍａｎｄｉｍｍｉｎｅｎｔａｎｏｍａｌｉｅｓｏｆｗａｔｅｒｒａｄｏｎｂｅ┐ｆｏｒｅｅａｒｔｈｑｕａｋｅｉｎｔｈｅｍａｉｎｌａｎｄｏｆＣｈｉｎａＸＵＥ－ＢＩＮＤＵ（杜学彬），Ｘ...     

Seismic response to electromagnetic sounding of the Earth’s lithosphere

The seismic catalogues of 1967?C2008 for the Bishkek geodynamical test site are analyzed for the purpose of studying the response of seismic activity to the electromagnetic sounding of the Earth??s crust during two series of field experiments with high-power controlled sources. The first series of the experiments, which were carried out in 1982?C1990, utilized the pulses provided by a magnetohydrodynamic (MHD) generator. The sounding signals in the second series of the experiments (2000?C2005) were generated by the capacitor-thyristor source ERGU 600-2. In these experiments, temporal variations of the set of statistical parameters characterizing the seismicity, which are typically used in the studies of the background and transient modes of seismicity, were investigated in a selected spatial domain within 150 km from the current electrodes. In terms of time, the analysis was conducted on two levels of detail. The study on a temporal scale of a few years was focused on the variations that preceded, accompanied, and followed the series of the experiments, while the day-scale analysis considered variations that were observed within 10 days after each sounding event. The day-scale analysis yields the following results. The slope of the frequency-magnitude diagram of the earthquakes (b value) during the sounding events is substantially larger than its background value. The slope of the graph gradually becomes gentler within about a day and a half after termination of sounding. The seismic activity slightly enhances during the interval of sounding and abates after its termination to a minimum, which corresponds to the interval of decreasing b value. This character of variations in seismicity differs from the scenario previously established for other transitional seismic regimes. The analysis on a temporal scale of a few years revealed variations in the studied parameters of the seismicity, some of which fall in both sounding intervals of 1983?C1990 and 2000?C2005. However, these variations are not unique; their character and durations suggest their being associated with the processes of preparation and after effects of the strong earthquakes that occurred in the vicinity of the sounding dipole.     

The use of bioestimation—a new method for the control of water self-purification

Examples are given of the application of bioestimation??a conceptually new hydrobiological method used to control the process of water quality formation. This paper is the continuation of the paper ??Bioestimation: A New Method for the Control of Water Self-Purification Process and Its Comparison with Bioindication??. The experience in the use of bioestimation in water bodies with different use type, size, salinity, flowage, and geographic position confirmed its universal character, information value, promptness, and the possibility to limit the volume of sample to be sent to 10?C20 cm³, thus simplifying the field works. Each significant factor, which affects the self-purification process, is identified independently, since the bioestimators reflecting it are biotically independent; their number varies depending only on changes in the environmental factors that are external with respect to the community of environmental factors. Bioestimation shows prognostic properties, since it makes it possible to prevent water quality deterioration and to restore the normal course of water self-purification at the stage of its quality formation. The use of bioestimation will extend the positive anthropogenic impact on water bodies.     

Comparison of the Penman‐Monteith method and regional calibration of the Hargreaves equation for actual evapotranspiration using SWAT-simulated results in the Seolma-cheon basin,South Korea

ABSTRACT

The Hargreaves method provides reference evapotranspiration (ET_o) estimates when only air temperature data are available, although it requires previous local calibration for an acceptable performance. This method was evaluated using the data from 71 meteorological stations in the Seolma-cheon basin (8.48 km²), South Korea, comparing daily estimates against those from the Penman‐Monteith (PM) method, which was used as the standard. To estimate reference ET_o more exactly, considering the climatological characteristics in South Korea, parameter regionalization of the Hargreaves equation is carried out. First, the modified Hargreaves equation is presented after an analysis of the relationship between solar radiation and temperature. Second, parameter (K_ET) optimization of the regional calibration of the Hargreaves equation (RCH) is performed using the PM method and the modified equation at 71 meteorological stations. Next, an application was carried out to evaluate the evapotranspiration methods (PM, original Hargreaves and RCH) in the SWAT (Soil and Water Assessment Tool) model by comparing these with the measured actual evapotranspiration (AET) in the basin. The SWAT model was calibrated using 3 years (2007–2009) of daily streamflow at the watershed outlet and 3 years (2007–2009) of daily AET measured at a mixed forest. The model was validated with 3 years (2010‐2012) of streamflow and AET. RCH will contribute to a better understanding of evapotranspiration of an ungauged watershed in areas where meteorological information is scarce.

EDITOR D. Koutsoyiannis ASSOCIATE EDITOR Not assigned     

The Q value variations in the preparing pro－cess of rock rupture

ＴｈｅＱｖａｌｕｅｖａｒｉａｔｉｏｎｓｉｎｔｈｅｐｒｅｐａｒｉｎｇｐｒｏ┐ｃｅｓｏｆｒｏｃｋｒｕｐｔｕｒｅＢＩＮＷＡＮＧ１）（王彬），ＺＨＡＯ－ＹＯＮＧＸＵ１）（许昭永），ＪＩＮ－ＭＩＮＧＺＨＡＯ１）（赵晋明）ＹＩ－ＬＩＨＵ２）（胡毅力）１）Ｓｅｉ...     

3D Modeling and Born approximation inversion for the borehole surface electromagnetic method

We present a 3D approach to numerical modeling of the borehole-surface electromagnetic （BSEM） method. The 3D electromagnetic response created by a vertical line current source in a layered medium is modeled using the 3D integral equation method. The modeling results are consistent with analytical solutions. 3D Born approximation inversion of BSEM data is also conducted for reservoir delineation. The inversion method is verified by a synthetic reservoir model.