Acta Geodaetica et Geophysica Hungarica

The gravimetric model of the Moho discontinuity is usually derived based on isostatic adjustment theories considering floating crust on the viscous mantle. In computation of such a model some a priori information about the density contrast between the crust and mantle and the mean Moho depth are required. Due to our poor knowledge about them they are assumed unrealistically constant. In this paper, our idea is to improve a computed gravimetric Moho model, by the Vening Meinesz-Moritz theory, using the seismic model in Fennoscandia and estimate the error of each model through a combined adjustment with variance component estimation process. Corrective surfaces of bi-linear, bi-quadratic, bi-cubic and multi-quadric radial based function are used to model the discrepancies between the models and estimating the errors of the models. Numerical studies show that in the case of using the bi-linear surface negative variance components were come out, the bi-quadratic can model the difference better and delivers errors of 2.7 km and 1.5 km for the gravimetric and seismic models, respectively. These errors are 2.1 km and 1.6 km in the case of using the bi-cubic surface and 1 km and 1.5 km when the multi-quadric radial base function is used. The combined gravimetric models will be computed based on the estimated errors and each corrective surface.

M. Eshagh

M. Bagherbandi

Quality description for gravimetric and seismic moho models of fennoscandia through a combined adjustment

通过综合调整对芬诺斯堪的亚重力和地震莫霍面模型的质量描述

A new, alternative solution of the exterior orientation in photogrammetry is given. The exterior orientation of sensors (e.g. camera-systems) is one of the basic tasks of photogrammetry. The parameters for exterior orientation can be determined from the mathematical equations between the image coordinates and the corresponding object or ground coordinates. The mathematical models for this problem have been available since decades, huge program packages utilize the methods which have proved to be successful in practice. In spite of this we propose in this work an alternative solution which does not use iteration and approximative data. The equations in this work are in coherence with the photogrammetric theory of exterior orientation, the only difference is in the mathematical solution. This kind of mathematical treatment of the problem can be considered as novel, its practical application may come later.

J. Závoti

D. Fritsch

A first attempt at a newalgebraic solution of the exterior orientation of photogrammetry

摄影测量外方位元素新代数解法初探

Outliers in geodetic networks badly affect all parameters and their variances estimated by least-squares. Tests for outliers (e.g. Baarda’s and Pope’s tests) are frequently used to detect outliers in geodetic networks. To measure the ability of these tests, the mean success rate (MSR) is proposed. Studies have shown that the MSRs of these tests in geodetic networks are low due to the smearing effect of the least-squares estimation even if there is only one outlier in the data set. In this paper, a new approach, for small outliers, is presented to increase the MSRs of the tests for outliers in geodetic networks. The main idea is that if the weight of one observation is increased, the corresponding studentized or normalized residuals are increased, too. This thesis is proved. Hence, the ability of the tests to detect outliers can be increased by appropriately increasing the weight of one observation at a time and repeating this for all observations. This approach is applied to three simulated geodetic networks. We show that the MSRs of the outlier tests are improved by approximately 5% if there is one small outlier in the data set. However, the improvements in the MSRs for more than one outlier are low.

S. Hekimoglu

B. Erdogan

R. C. Erenoglu

R. G. Hosbas

Increasing the efficacy of the tests for outliers for geodetic networks

提高大地测量网中异常值检测的效率

Low velocity surface layers can significantly increase ground accelerations during earthquakes. When saturated sandy sediments are present, because of pore pressure increase, decrease of soil strength or even liquefaction can occur. Some volume change follows the dissipation of excess pore pressure after the earthquake resulting surface settlements. To determine the liquefaction probability and post-liquefaction settlement is very important for critical facilities e.g. for the site of Paks Nuclear Power Plant, Hungary. Pore pressure increase and so the liquefaction and surface settlements depend on the characteristics of seismic loading and soil parameters. To quantify the extent of these phenomena is rather difficult. Uncertainties arise both from the probabilistic nature of the earthquake loading and from the simplifications of soil models as well. In the paper, the most important semi-empirical and dynamical effective stress methods for liquefaction and post-liquefaction settlement assessment are summarized. Most significant contributors to the uncertainties are highlighted, and particular examples through the investigation of Paks NPP site are given. Finally, a probabilistic procedure is proposed where the uncertainties will be taken into account by applying a logic tree methodology. At the same time, the uncertainties are reduced by the use of site-specific UHRS and stress reduction factors.

E. Győri

L. Tóth

Z. Gráczer

T. Katona

Liquefaction and post-liquefaction settlement assessment — A probabilistic approach

液化及液化后沉降评估——一种概率方法

Exceptional geomagnetic storms were observed in late August and early September 1859. Auroras were observed around the world, and telegraph wires were damaged. Until now, there has been no evidence published of auroral observations in Spain during this famous space weather event. This paper presents Spanish observations that show the aspect of this great aurora from Spain, and the concurrent effects on European telegraph wires. We also computed the variation of the geomagnetic declination in Spain during recent centuries to put these records into context.

A. M. M. Farrona

M. C. Gallego

J. M. Vaquero

F. Domínguez-Castro

Spanish eyewitness accounts of the great space weather event of 1859

1859年特大空间天气事件的西班牙目击者证词

In connection with the EURISGIC WP2 project the authors present those procedures which have been used to construct a map in cells on the electrical resistivity distribution in Europe at least till to the asthenosphere. The data are based on the deep magnetotelluric soundings published in the international literature. This map is the basis of the calculation of the induction risk endangering the electric network and communication systems.

A. Ádám

E. Prácser

V. Wesztergom

Estimation of the electric resistivity distribution (EURHOM) in the european lithosphere in the frame of the eurisgic WP2 project

欧洲岩石圈电阻率分布（EURHOM）在EURISGIC WP2项目框架下的估算

In the present study the crustal structures of Nile Delta, including Greater Cairo province, and its surroundings, were evaluated using 3D forward gravity and magnetic modeling. The interpretation is also based on the seismic reflection results, well logs data and previous density models. The present results allow to improve the understanding of both the crustal thicknesses and density distributions between the sedimentary cover and the upper mantle in the study area.The high Bouguer anomalies near the Mediterranean coast are mainly caused by deep-seated structures. The crust beneath the Mediterranean coastal region is typically continental, with a thickness of 24 km beneath Rositta and Damitta branches, which increases toward the south. The Greater Cairo province has been modeled with maximum crustal thickness of ca. 34 km. The negative gravity anomalies with minimum values are due to the effect of sedimentary cover and/or basement relief geometry.The main results of this work suggest that the study area...

S. Saleh

3D crustal structure and its tectonic implication for nile delta and greater cairo regions, egypt, from geophysical data

埃及尼罗河三角洲及大开罗地区三维地壳结构及其构造意义的地震数据研究

This paper presents a new approach for precision estimation for algebraic ellipse fitting based on combined least squares method. Our approach is based on coordinate description of the ellipse geometry to determine the error distances of the fitting method. Since it is an effective fitting algorithm the well-known Direct Ellipse Fitting method was selected as an algebraic method for precision estimation. Once an ellipse fitted to the given data points, algebraic distance residuals for each data point and fitting accuracy can be computed. Generally, the adopted approach has revealed geometrical aspect of precision estimation for algebraic ellipse fitting. The experimental results revealed that our approach might be a good choice for precision estimation of the ellipse fitting method.

O. Kurt

O. Arslan

Geometric interpretation and precision analysis of algebraic ellipse fitting using least squares method

代数椭圆拟合的解析几何解释与精度分析

A new probabilistic seismic hazard assessment for Albania is carried out using the smoothed gridded seismicity approach. Albania's earthquake catalogue is already revised and expanded, covering a study area limited by 38 − 44.5°N Latitude and 18 − 24°E Longitude, and the time period from 58BC to 31/12/2008. The ground motion hazard map is presented over a 10 km grid in terms of peak ground acceleration for 10% probability of exceedance in 50 years, corresponding to 475-year return period. The reference site condition is firm rock, defined as having an average shear-wave velocity in the upper 30 m of the crust of 800 m/sec. It is the standard reference site condition used by the European seismic code (Eurocode 8) for seismic zonation and building codes. The main finding is that if this map is accepted as a reference indicator to establish a new regulatory national seismic zonation, design acceleration will be much higher than that applied in the current regulation. This implies that the competent authorities should take into consideration the obtained results to improve the existing design code in a more reliable and realistic basis in order to increase the safety level of constructions in the country.

涉及主题	地质学物理地理工程类量子力学计算机科学生物数学大地测量学天文地震学古生物学地球物理学几何学
出版信息	出版商: Akademiai Kiado，出版周期: Quarterly，期刊类型: journal，开源期刊: 否
基本数据	创刊年份: 1994，原创研究文献占比: 0.00%，自引率:N.A.， Gold OA占比: 0.00%
平均审稿周期	网友分享经验：>12周，或约稿
平均录用比例	网友分享经验：容易

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Quality description for gravimetric and seismic moho models of fennoscandia through a combined adjustment

A first attempt at a newalgebraic solution of the exterior orientation of photogrammetry

Increasing the efficacy of the tests for outliers for geodetic networks

Liquefaction and post-liquefaction settlement assessment — A probabilistic approach

Spanish eyewitness accounts of the great space weather event of 1859

Estimation of the electric resistivity distribution (EURHOM) in the european lithosphere in the frame of the eurisgic WP2 project

3D crustal structure and its tectonic implication for nile delta and greater cairo regions, egypt, from geophysical data

Quality description for gravimetric and seismic moho models of fennoscandia through a combined adjustment

Geometric interpretation and precision analysis of algebraic ellipse fitting using least squares method

Probabilistic seismic hazard assessment of Albania