On the applicability of KirchofPs law and the principle of heat balance in thermal infrared remote sensing:A non-isothermal system

This paper proposes a basic equation of thermal radiation interaction between surface objects on the basis of the principle of heat balance in the interface. The solution of this equation takes account of the contribution of sensible heat flux and latent heat flux more completely, compared with traditional solution for surface cooling and heating processes. By the aid of the experimental data conducted in the Xiaotangshan experimental site, Beijing, both the non-applicability of Kirchoff's law and the measurability of surface emissivity in a non-isothermal system have been highlighted. Two methods called ventilation and time-delay compensations have been proposed to reduce the error induced by change of surface temperatures of non-isothermal objects during the measurement of emissivity. Based on the solution of the basic equation, this paper has analyzed and pointed out the misunderstanding in comprehension and application of Kirchoff's law published in literature.     

Source time-function as discriminant using empirical Green’s function

Since the sign up of CTBT (Comprehensive Test Ban Treaty), the nuclear monitoring and distinguishing has gained great attention by the treaty countries. Seismology is one of the primary technical means available for monitoring compliance to a CTBT. However, there does not exist a single criterion, so far, that can effectively distinguish explorations from earthquakes. It has been known that source time function (abbreviated to STF) of an underground nuclear explosion contains important p…     

A study on the focal parameters of Shidian M =5.9 earthquake sequences in 2001

On the basis of about 300 earthquake wave forms observed in the Shidian M _S=5.9 sequences on April 12, 2001 recorded in Kunming Digital Seismic Network, the spectra of shear wave have been used to estimate the focal parameters of these earthquake sequences. The results show that within the magnitude range of 1.5–5.3, the seismic moments are 10¹⁰–10¹⁶ N·m, the corner frequencies are 0.2–0.8 Hz, radii of the focal rupture are 200–2 500 m and the stress drops are 0.1×10⁵–20×10⁵Pa. Through the statistical analyses of variation of corner frequency f _c and stress drop Δσ with time, it is discovered that the average corner frequency of the foreshock sequences is obviously lower than that of the aftershock sequences. Contrarily, the average stress drops Δσ of the foreshock sequences are clearly higher than that of the aftershocks. It is considered that these variation characteristics of average corner frequency and stress drops before and after the main shock have index significance to the precursory information before a strong earthquake. The higher stress drops for the foreshock sequences show that the higher shear stresses have been stored in the area of main shock. After the main shock, most of the stresses have been released, so the aftershock sequences show a rupture process of lower stresses. Foundation item: Scientific and Technological Key Project of Yunnan Province (2001NG46)     

2-D crustal Poisson’s ratio from seismic travel time inversion in Changbaishan Tianchi volcanic region

Based on the inversion method of 2D velocity structure and interface, the crustal velocity structures of P-wave and S-wave along the profile L ₁ are determined simultaneously with deep seismic sounding data in Changbaishan Tianchi volcanic region, and then its Poisson’s ratio is obtained. Calculated results show that this technique overcomes some defects of traditional forward calculation method, and it is also very effective to determine Poisson’s ratio distribution of deep seismic sounding profile, especially useful for study on volcanic magma and crustal fault zone. Study result indicates that there is an abnormally high Poisson’s ratio body that is about 30 km wide and 12 km high in the low velocity region under Tianchi crater. Its value of Poisson’s ratio is 8% higher than that of surrounding medium and it should be the magma chamber formed from melted rock with high temperature. There is a high Poisson’s ratio zone ranging from magma chamber to the top of crust, which may be the uprise passage of hot substance. The lower part with high Poisson’s ratio, which stretches downward to Moho, is possibly the extrusion way of hot substance from the uppermost mantle. The conclusions above are consistent with the study results of both tomographic determination of 3D crustal structure and magnetotelluric survey in this region. Foundation item: Key Project from China Earthquake Administration and the Project (95-11-02-01) from Ministry of Science and Technology (2001DIA10003). Contribution No. RCEG200401, Geophysical Exploration Center, China Earthquake Administration.     

Viscosity of peridotite liquid up to 13 GPa: Implications for magma ocean viscosities

The viscosity of synthetic peridotite liquid has been investigated at high pressures using in-situ falling sphere viscometry by combining a multi-anvil technique with synchrotron radiation. We used a newly designed capsule containing a small recessed reservoir outside of the hot spot of the heater, in which a viscosity marker sphere is embedded in a forsterite + enstatite mixture having a higher solidus temperature than the peridotite. This experimental setup prevents spheres from falling before a stable temperature above the liquidus is established and thus avoids difficulties in evaluating viscosities from velocities of spheres falling through a partially molten sample.

Experiments have been performed between 2.8 and 13 GPa at temperatures ranging from 2043 to 2523 K. Measured viscosities range from 0.019 (± 0.004) to 0.13 (± 0.02) Pa s. At constant temperature, viscosity increases with increasing pressure up to  8.5 GPa but then decreases between  8.5 and 13 GPa. The change in the pressure dependence of viscosity is likely associated with structural changes of the liquid that occur upon compression. By combining our results with recently published 0.1 MPa peridotite liquid viscosities [D.B. Dingwell, C. Courtial, D. Giordano, A. Nichols, Viscosity of peridotite liquid, Earth Planet. Sci. Lett. 226 (2004) 127–138.], the experimental data can be described by a non-Arrhenian, empirical Vogel-Fulcher-Tamman equation, which has been modified by adding a term to account for the observed pressure dependence of viscosity. This equation reproduces measured viscosities to within 0.08 log₁₀-units on average. We use this model to calculate viscosities of a peridotitic magma ocean along a liquid adiabat to a depth of  400 km and discuss possible effects on viscosity at greater pressures and temperatures than experimentally investigated.     

Signatures in flowing fluid electric conductivity logs

Flowing fluid electric conductivity logging provides a means to determine hydrologic properties of fractures, fracture zones, or other permeable layers intersecting a borehole in saturated rock. The method involves analyzing the time-evolution of fluid electric conductivity (FEC) logs obtained while the well is being pumped and yields information on the location, hydraulic transmissivity, and salinity of permeable layers. The original analysis method was restricted to the case in which flows from the permeable layers or fractures were directed into the borehole (inflow). Recently, the method was adapted to permit treatment of both inflow and outflow, including analysis of natural regional flow in the permeable layer. A numerical model simulates flow and transport in the wellbore during flowing FEC logging, and fracture properties are determined by optimizing the match between simulation results and observed FEC logs. This can be a laborious trial-and-error procedure, especially when both inflow and outflow points are present. Improved analyses methods are needed. One possible tactic would be to develop an automated inverse method, but this paper takes a more elementary approach and focuses on identifying the signatures that various inflow and outflow features create in flowing FEC logs. The physical insight obtained provides a basis for more efficient analysis of these logs, both for the present trial and error approach and for a potential future automated inverse approach. Inflow points produce distinctive signatures in the FEC logs themselves, enabling the determination of location, inflow rate, and ion concentration. Identifying outflow locations and flow rates typically requires a more complicated integral method, which is also presented in this paper.     

Knowledge Representation Methods in Expert System for Earthquake Prediction ESEP 3.0

INTRODUCTIONKnowledgerepresentationandknowledgeacquisitionarekeyissuesinbuildinganexpertsystem .Theyarecloselyrelatedtothedomainproblem solvinglevelandcompetenceoftheexpertsystem .Intheknowledgeacquisitionprocess,thedomainexpertwillfirstofferandorganizepr…     

南半球对流层气候年代际变化及其与太阳活动的联系

通过南半球对流层温度场谱分析和逐次滤波分析发现，南半球对流层大气温度场半个多世纪以来呈现明显的持续升温趋势，升温幅度由低层到高层逐步增加，其中地面层1 000 hPa年升温率为0.013℃/a，对流层中部500 hPa年升温率为0.019℃/ a，对流层上部300 hPa年升温率为0.036℃/ a；滤除南半球大气温度场的趋势变化，发现南半球大气温度场从地面层直至对流层顶广泛盛行着十分显著的与太阳磁场磁性22年周期变化相一致的变化周期。太阳磁场磁性周期变化趋势略有超前，分析认为，这是南半球对流层大气气候系统对太阳磁场周期性变化的响应。进一步分析还发现，南半球从地面层1 000 hPa到对流层顶，再到平流层中部10 hPa各层次大气温度变化22年周期分量振荡位相基本一致，周期振幅由低层到高层迅速增大，说明太阳磁场变化对对流层高层比低层影响大，对平流层影响更大。其中地面层1 000 hPa温度场的22年变化周期是在滤除趋势变化和11年周期之后才显现出来的，所以太阳磁场磁性周期变化对地面层气候的影响较小并且经常处于被掩盖状态；南半球地面层1 000 hPa温度场滤除趋势变化之后显示出十分显著的与太阳活动11年周期相一致的变化周期，分析认为，这是南半球对流层大气气候系统对太阳活动11周期性变化的响应。对流层上层300 hPa温度场滤除趋势变化和22年周期之后也显示出11年变化周期，而对流层中部500 hPa则无此周期反应，说明太阳活动11年周期对地面层1 000 hPa大气气候影响最明显，对流层中上层影响较弱。     

元谋人时代研究评述——兼论我国早更新世古人类时代问题

我国早更新世古人类遗址时代的确定对于认识早期人类起源、扩散与演化具有重要意义。对元谋人化石的各种年龄测定结果和认识分歧进行了综合评述。综合分析认为，在翔实的岩石地层学和古生物地层学基础上，开展高分辨率磁性地层学研究是解决包括元谋人在内的这一时期哺乳动物时代科学问题的最有效的研究途径。