Probabilistic predictive model with complex remembrance

（王键）Ｐｒｏｂａｂｉｌｉｓｔｉｃｐｒｅｄｉｃｔｉｖｅｍｏｄｅｌｗｉｔｈｃｏｍｐｌｅｘｒｅｍｅｍｂｒａｎｃｅ￥ＪｉａｎＷＡＮＧ（ＩｎｓｔｉｔｕｔｅｏｆＧｅｏｐｈｙｓｉｃｓ，ＳｔａｔｅＳｅｉｓｍｏｌｏｇｉｃａｌＢｕｒｅａｕ，Ｂｅｉｊｉｎｇ１０００８１，...     

Binomial model on seismic risk analysis

ＢｉｎｏｍｉａｌｍｏｄｅｌｏｎｓｅｉｓｍｉｃｒｉｓｋａｎａｌｙｓｉｓＪｉａｎＷＡＮＧ（王健）ａｎｄＺｈｅｎ－ＬｉａｎｇＳＨＩ（时振梁）（ＩｎｓｔｉｔｕｔｅｏｆＧｅｏｐｈｙｓｉｃｓ，ＳｔａｔｅＳｅｉｓｍｏｌｏｇｉｃａｌＢｕｒｅａｕ，Ｂｅｉｊｉｎｇ１００...     

Parker’s model in geodynamo

The eigenvalue problem for Parker’s dynamo model is considered. We study how the intensity of convection in the liquid core of the Earth affects the generation of the geomagnetic field with different directions of latitudinal field propagation. The scenarios of transition of the geomagnetic field from frequent to rare reversals are suggested.     

A kinematics-uplift model for the HimalayanTibetan region

Ａｋｉｎｅｍａｔｉｃｓ－ｕｐｌｉｆｔｍｏｄｅｌｆｏｒｔｈｅＨｉｍａｌａｙａｎＴｉｂｅｔａｎｒｅｇｉｏｎＸｉａｎ－ＪｉｅＳＨＥＮ（沈显杰）ａｎｄＬａｄｉｓｌａｕｓＲＹＢＡＣＨ（ＩｎｓｔｉｔｕｔｅｏｆＧｅｏｌｏｇｙ，ＡｃａｄｅｍｉａＳｉｎｉｃａ，Ｂｅｉｊ...     

Cellular automation model of faults and algorithmic complexity

Ｃｅｌｌｕｌａｒ　ａｕｔｏｍａｔｉｏｎ　ｍｏｄｅｌ　ｏｆ　ｆａｕｌｔｓ　ａｎｄ　ａｌｇｏｒｉｔｈｍｉｃ　ｃｏｍｐｌｅｘｉｔｙ（陆远忠）（吕悦军）Ｃｅｌｌｕｌａｒａｕｔｏｍａｔｉｏｎｍｏｄｅｌｏｆｆａｕｌｔｓａｎｄａｌｇｏｒｉｔｈｍｉｃｃｏｍｐｌｅｘｉ...     

NOC model of the earth's main magnetic field

The international geomagnetic reference field (IGRF) is a standard model for describing the spatial structure and temporal variation of the earth抯 main magnetic field[1—3]. The first IGRF model, designated IGRF 1965, was adopted by IAGA in 1968[4]. In l…     

Construction of constant-Q viscoelastic model with three parameters

The popularly used viscoelastic models have some shortcomings in describing relationship between quality factor (Q) and frequency, which is not consistent with the observation data. Based on the theory of viscoelasticity, a new approach to construct constant-Q viscoelastic model in given frequency band with three parameters is developed. The designed model describes the frequency-independence feature of quality factor very well, and the effect of viscoelasticity on seismic wave field can be studied relatively accurate in theory with this model. Furthermore, the number of required parameters in this model has been reduced fewer than that of other constant-Q models, this can simplify the solution of the viscoelastic problems to some extent. At last, the accuracy and application range have been analyzed through numerical tests. The effect of viscoelasticity on wave propagation has been briefly illus-trated through the change of frequency spectra and waveform in several different viscoelastic models.     

Application of a time-magnitude prediction model for earthquakes

In this paper we discuss the physical meaning of the magnitude-time model parameters for earthquake prediction. The gestation process for strong earthquake in all eleven seismic zones in China can be described by the magnitude-time prediction model using the computations of the parameters of the model. The average model parameter values for China are： b = 0.383, c=0.154, d = 0.035, B = 0.844, C = -0.209, and D = 0.188. The robustness of the model parameters is estimated from the variation in the minimum magnitude of the transformed data, the spatial extent, and the temporal period. Analysis of the spatial and temporal suitability of the model indicates that the computation unit size should be at least 4°× 4°for seismic zones in North China, at least 3° × 3° in Southwest and Northwest China, and the time period should be as long as possible.     

Global test of seismic static stress triggering model

Introduction Whether static stress change generated by earthquakes can trigger subsequent earthquakes heretofore is still in debate. Some researchers believe that seismic Coulomb failure stress change generated by earthquake can affect the seismicity nearby (King, et al, 1994; Toda, et al, 1998; Stein, 1999; Seeber, Armbruster, 2000). However, some researchers believe that this model is wrong. For example, Beroza and Zoback (1993) found that stress change generated by the 1989 Loma Prieta …     

A swallow-tail type catastrophic model of earthquake process

（殷有泉）（杜静）Ａｓｗａｌｌｏｗ－ｔａｉｌｔｙｐｅｃａｔａｓｔｒｏｐｈｉｃｍｏｄｅｌｏｆｅａｒｔｈｑｕａｋｅｐｒｏｃｅｓｓ￥Ｙｏｕ－ＱｕａｎＹＩＮａｎｄＪｉｎｇＤＵ（ＰｅｋｉｎｇＵｎｉｖｅｒｓｄｙ，Ｂｅｉｊｉｎｇ１００８７１，Ｃｈｉｎａ）（Ｎｏｒｔ...     

Wavefield continuation datuming using a near surface model

When topography and low velocity zone differences vary greatly, conventional vertical static time shifts will cause wavefield distortion and influence wave equation seismic imaging for seismic data acquired on a complex near surface. In this paper, we propose an approach to datum correction that combines a joint tomography inversion with wavefield continuation to solve the static problem for seismic data on rugged acquisition topography. First, the near surface model is obtained by refracted wave tomography inversion. Second, the wavefield of sources and receivers are continued downward and upward to accomplish datum correction starting from a flat surface and locating the datum above topography. Based on the reciprocal theorem, Huygens＇ and Fresnel principles, the location of sources and receivers, and regarding the recorded data on the surface as a secondary emission, the sources and receivers are upward-continued to the datum above topography respectively. Thus, the datum correction using joint tomography inversion and wavefield continuation with the condition of a complex near surface is accomplished.     

Data assimilation in Parker’s dynamo model

Application of the extended Kalman filter in the data assimilation problem of the one-dimensional (1D) Parker dynamo model is considered for two extreme cases: (1) when the magnetic field observations are taken uniformly across the entire surface of the liquid core of the Earth and (2) when the observations are taken at one spatial point. The algorithm allows the model solution with arbitrary initial conditions to be modified based on observations. It is shown that the redundancy of the noised data can reduce the efficiency of the recovery of the solution. Considerations on the applicability of data assimilation for the case of a higher dimension and a solution’s convergence dependent on the density of the flow of information assimilated are suggested.     

Modelling of fluid–solid interactions using an adaptive mesh fluid model coupled with a combined finite–discrete element model

Fluid–structure interactions are modelled by coupling the finite element fluid/ocean model ‘Fluidity-ICOM’ with a combined finite–discrete element solid model ‘Y3D’. Because separate meshes are used for the fluids and solids, the present method is flexible in terms of discretisation schemes used for each material. Also, it can tackle multiple solids impacting on one another, without having ill-posed problems in the resolution of the fluid’s equations. Importantly, the proposed approach ensures that Newton’s third law is satisfied at the discrete level. This is done by first computing the action–reaction force on a supermesh, i.e. a function superspace of the fluid and solid meshes, and then projecting it to both meshes to use it as a source term in the fluid and solid equations. This paper demonstrates the properties of spatial conservation and accuracy of the method for a sphere immersed in a fluid, with prescribed fluid and solid velocities. While spatial conservation is shown to be independent of the mesh resolutions, accuracy requires fine resolutions in both fluid and solid meshes. It is further highlighted that unstructured meshes adapted to the solid concentration field reduce the numerical errors, in comparison with uniformly structured meshes with the same number of elements. The method is verified on flow past a falling sphere. Its potential for ocean applications is further shown through the simulation of vortex-induced vibrations of two cylinders and the flow past two flexible fibres.     

Modelling of fluid–solid interactions using an adaptive mesh fluid model coupled with a combined finite–discrete element model

Fluid–structure interactions are modelled by coupling the finite element fluid/ocean model ‘Fluidity-ICOM’ with a combined finite–discrete element solid model ‘Y3D’. Because separate meshes are used for the fluids and solids, the present method is flexible in terms of discretisation schemes used for each material. Also, it can tackle multiple solids impacting on one another, without having ill-posed problems in the resolution of the fluid’s equations. Importantly, the proposed approach ensures that Newton’s third law is satisfied at the discrete level. This is done by first computing the action–reaction force on a supermesh, i.e. a function superspace of the fluid and solid meshes, and then projecting it to both meshes to use it as a source term in the fluid and solid equations. This paper demonstrates the properties of spatial conservation and accuracy of the method for a sphere immersed in a fluid, with prescribed fluid and solid velocities. While spatial conservation is shown to be independent of the mesh resolutions, accuracy requires fine resolutions in both fluid and solid meshes. It is further highlighted that unstructured meshes adapted to the solid concentration field reduce the numerical errors, in comparison with uniformly structured meshes with the same number of elements. The method is verified on flow past a falling sphere. Its potential for ocean applications is further shown through the simulation of vortex-induced vibrations of two cylinders and the flow past two flexible fibres.

     

Seismotectonic model of the Tainan basin, southwestern Taiwan

Introduction In the 20th century, there are 5 destructive earthquakes and their associated earthquake faults happened in the Tainan basin. They are the 1906 Chiayi earthquake and Meishan fault (Omori, 1907), the 1941 Chungpu earthquake and Ichu fault (LIN, et al, 1998), the 1946 Tainan earthquake and Hsinhua fault (ZHANG, et al, 1947), the 1994 Taiwan Strait earthquake and transtenssion zone of Ichu fault (KAO, WU, 1996), the 1999 Chiayi earthquake and the contractional strike-slip d…     

Cone model for two surface foundations on layered soil

In this paper, the cone model is applied to the vibration analysis of two foundations on a layered soil half space. In the analysis, the total stress field in the subsoil is divided into the free-field and the scattering field. Seed＇s simplified method is adopted for the free-field analysis, while the cone model is proposed for analyzing the dynamic scattering stress wave field. The shear stress field and the compressive stress field in the layered stratum with two scattering sources are calculated by shear cone and compressive cone, respectively. Furthermore, the stress fields in the subsoil with two foundations are divided into six zones, and the P wave and S wave are analyzed in each zone. Numerical results are provided to illustrate features of the added stress field for two surface foundations under vertical and horizontal sinusoidal force excitation. The proposed cone model may be useful in handling some of the complex problems associated with multi-scattering sources.     

A poincaré model for the earth's fluid core

Abstract

The superconducting-gravimeter data of Melchior and Ducarme (1986) has been interpreted as internal motion in the Earth's core by Aldridge and Lumb (1987) using a Poincaré model. Several low-order modes with periods of 13–16 hours have been tentatively identified in the core which is taken to be an incompressible, homogeneous fluid within a rigid, rotating container. The identification is based on asymptotic values of the frequencies which change slowly with time while the modes decay with an e-folding time of about 280 days. The slow change in frequency with time implies a small temporal variation in the rotation rate of the core. This mean flow is a nonlinear effect often observed in laboratory experiments designed to excite Poincaré modes. Interaction among modes during free ringdown is also observed in those experiments and apparently in the data of Melchior et al. (1988) as well. Laboratory work thus provides the link to extend the Poincaré model to include viscous and nonlinear effects in order to interpret the gravimetric observations as core modes.     

A traveling epidemic model of space–time disease spread

This work presents a random field model of disease attribute (incidence, mortality etc.) that transfers the study of the attribute distribution from the original spatiotemporal domain onto a lower-dimensionality traveling domain that moves along the direction of disease velocity. The partial differential equations connecting the disease attribute covariances in the original and the traveling domain are derived with coefficients that are functions of the disease velocity. These equations offer epidemiologic insight concerning the strength of the space–time dependence between the disease attribute values in the two domains. The traveling disease model has certain theoretical and computational advantages in the study and prediction of space–time disease attribute distributions in conditions of uncertainty. Estimates of the disease attribute are derived in the traveling domain and then used to generate maps of space–time disease attribute distribution in the original domain. The theoretical model is illustrated and additional insight is gained by means of a numerical mortality simulation study, which shows that the proposed model is at least as accurate but computationally more efficient than mainstream mapping techniques of higher dimensionality. These findings concerning the very good predictability of the proposed model also strongly support its adequacy to represent the space–time mortality distribution.     

Antarctic circumpolar modes in a coupled ocean–atmosphere model

Eastward-propagating patterns in anomalous potential temperature and salinity of the Southern Ocean are analyzed in the output of a 1000-year simulation of the global coupled atmosphere–ocean GCM ECHO-G. Such features can be associated with the so-called Antarctic Circumpolar Wave (ACW). It is found that time–longitude diagrams that have traditionally been used to aid the visualization of the ACW are strongly influenced by the width of the bandpass time filtering. This is due to the masking of considerable low-frequency variability that occurs over a broad range of time scales. Frequency–wavenumber analysis of the ACW shows that the eastward-propagating waves do have preferred spectral peaks, but that both the period and wavenumber change erratically when comparing different centuries throughout the simulation. The variability of the ACW on a variety of time scales from interannual to centennial suggests that the waiting time for a sufficient observational record to determine the time scale of variability of the real world ACW (and the associated decadal time scale predictability of climate for southern landmasses) will be a very long one.Responsible Editor: Dirk Olbers     

：~orous-grain-upper-boundary model and its application to Tarim Basin carbonates

Most of the carbonates in the Tarim Basin in northwest China are low-porosity and low-permeability rocks. Owing to the complexity of porosity in carbonates, conventional rock- physics models do not describe the relation between velocity and porosity for the Tarim Basin carbonates well. We propose the porous-grain-upper-boundary （PGU） model for estimating the relation between velocity and porosity for low-porosity carbonates. In this model, the carbonate sediments are treated as packed media of porous elastic grains, and the carbonate pores are divided into isolated and connected pores The PGU model is modified from the porous-grain-stiff-sand （PGST） model by replacing the critical porosity with the more practical isolated porosity. In the implementation, the effective elastic constants of the porous grains are calculated by using the differential effective medium （DEM） model. Then, the elastic constants of connected porous grains in dry rocks are calculated by using the modified upper Hashin-Shtrikman bound. The application to the Tarim carbonates shows that relative to other conventional effective medium models the PGU model matches the well log data well.