Studia Geophysica et Geodaetica最新文献

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Medium- and long-term prediction of length-of-day changes with the combined singular spectrum analysis and neural networks 奇异谱分析与神经网络相结合的日变化中长期预测
IF 0.5 4区 地球科学
Studia Geophysica et Geodaetica Pub Date : 2023-07-04 DOI: 10.1007/s11200-022-0558-6
Yu Lei, Danning Zhao, Min Guo
{"title":"Medium- and long-term prediction of length-of-day changes with the combined singular spectrum analysis and neural networks","authors":"Yu Lei,&nbsp;Danning Zhao,&nbsp;Min Guo","doi":"10.1007/s11200-022-0558-6","DOIUrl":"10.1007/s11200-022-0558-6","url":null,"abstract":"<div><p>Real-time estimates of the Earth orientation parameters (EOP) are currently unavailable for users owing to the delay caused by complex data processing and heavy computation procedures. Accurate short-term predictions of the EOP are therefore essential for several real-time applications such as navigation and tracking of interplanetary spacecrafts and precise orbit determination of Earth satellites, whilst medium- and long-term predictions are required for Global Navigation Satellite System (GNSS) autonomous satellite navigation, climate forecasting as well as for astrogeodynamic studies. Universal time (UT1 – UTC) or its first time derivative, length of day (ΔLOD), representing the changes of the Earth’s rotation rate, are the most challenging to predict among the EOP. Various methods and techniques have been used to improve ΔLOD predictions since the present prediction accuracy is yet unsatisfactory even up a few days into the future. This study employs a popular time-series analysis method, called singular spectrum analysis (SSA), in combination with the neural network (NN) technique for medium- and long-term prediction of ΔLOD up to 2 years in the future. The SSA is first applied to extracting the predominant periodic components including annual and semiannual oscillations and irregular short-period signals in ΔLOD data. These extracted predominant periodic components are then extrapolated by the proposed SSA-based data filling strategy. Next, the residuals (the difference between these predominant components and the data themselves) are modeled and predicted by the NN technique. The predicted ΔLOD value is sum of the extrapolation of the predominant periodic components and the prediction of the residuals. The results show that the accuracy of the 180-day ahead predictions is worse than that by the combination of least squares (LS) extrapolation and a stochastic method including autoregressive and NN technology in terms of the mean absolute prediction error. However, the proposed SSA extrapolation in combination with NN modeling can achieve a noticeably better accuracy for the medium- and long-term predictions out 180 days than the combined LS + stochastic technology. The improvement in the prediction accuracy for lead time of 1 year and 2 years can reach up to 53% and 56%, respectively. The combined SSA extrapolation and NN modeling is thus very promising for medium- and long-term prediction of ΔLOD.</p></div>","PeriodicalId":22001,"journal":{"name":"Studia Geophysica et Geodaetica","volume":"67 3-4","pages":"107 - 123"},"PeriodicalIF":0.5,"publicationDate":"2023-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43876707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Mesoproterozoic geomagnetic field strength from Nova Guarita mafic dykes (Amazon Craton) 亚马逊克拉通Nova Guarita岩脉的中元古代地磁场强度
IF 0.5 4区 地球科学
Studia Geophysica et Geodaetica Pub Date : 2023-07-04 DOI: 10.1007/s11200-022-0647-6
Anita Di Chiara, Adrian R. Muxworthy, Ricrdo I. F. Trindade, Franklin Bispo-Santos, Evelyn B. Baker
{"title":"Mesoproterozoic geomagnetic field strength from Nova Guarita mafic dykes (Amazon Craton)","authors":"Anita Di Chiara,&nbsp;Adrian R. Muxworthy,&nbsp;Ricrdo I. F. Trindade,&nbsp;Franklin Bispo-Santos,&nbsp;Evelyn B. Baker","doi":"10.1007/s11200-022-0647-6","DOIUrl":"10.1007/s11200-022-0647-6","url":null,"abstract":"<div><p>Palaeointensity data from the Precambrian are key to understanding the timing of the Earth’s Inner Core Nucleation (ICN). Due to the scarcity of data, the ICN timing is still poorly constrained and is thought to have occurred between 2500 to 500 Ma. Numerical dynamo simulation models predict an increase in entropy, a stronger driving force for convection that could affect the field strength and show an anomaly in the palaeointensity record at ICN. We present new estimates of the geomagnetic field intensity (palaeointensity) from the Mid-Mesoproterozoic (1406 ± 1424 Ma) Nova Guarita dyke swarm, in the northern Mato Grosso State (SW Amazon Craton, Brazil). To obtain palaeointensity estimates, we used the non-heating Preisach method, with palaeointensity criteria at the specimen, and site level. Five sites provided accepted palaeointensity results, yielding virtual dipole moment (VDM) estimate of 65 ± 12 ZAm<sup>2</sup> at 1416 ± 13 Ma, 53 ± 4 ZAm<sup>2</sup> at 1418 ± 3 Ma, 12 ± 2 and 8 ± 2 ZAm<sup>2</sup> at 1418 ± 5 Ma, and 71 ± 16 ZAm<sup>2</sup> at 1424 ± 16 Ma, thus an average estimate of 43 ± 30 ZAm<sup>2</sup> for ∼1410 Ma. The estimate is similar to the average VDM data (∼50 ZAm<sup>2</sup>), calculated for the period from 1600 to 1000 Ma. This average represents only a snapshot of the Earth’s magnetic field strength. While the new data are too limited in time to contribute directly to the question of ICN, they nevertheless contribute to constraints useful for assessing numerical simulations of the Mesoproterozoic geodynamo.</p></div>","PeriodicalId":22001,"journal":{"name":"Studia Geophysica et Geodaetica","volume":"67 3-4","pages":"161 - 182"},"PeriodicalIF":0.5,"publicationDate":"2023-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11200-022-0647-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48160970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A priori and effective estimation of variance factors based on the code chipping rate in BeiDou navigation satellite system positioning 基于码片率的北斗卫星导航系统定位方差因子先验有效估计
IF 0.9 4区 地球科学
Studia Geophysica et Geodaetica Pub Date : 2023-05-18 DOI: 10.1007/s11200-022-0452-2
Xuezhen Li, Zhetao Zhang, Yuan Li, Xiaomin Luo, Vagner G. Ferreira
{"title":"A priori and effective estimation of variance factors based on the code chipping rate in BeiDou navigation satellite system positioning","authors":"Xuezhen Li,&nbsp;Zhetao Zhang,&nbsp;Yuan Li,&nbsp;Xiaomin Luo,&nbsp;Vagner G. Ferreira","doi":"10.1007/s11200-022-0452-2","DOIUrl":"10.1007/s11200-022-0452-2","url":null,"abstract":"<div><p>In multi-frequency and multi-constellation BeiDou Navigation Satellite System (BDS), the observation type is increased, and the observation precision is inevitably different. Consequently, it is difficult to determine the variance factors of various observations. Variance component estimation can reasonably determine the weights of different types of observations and greatly improve positioning accuracy, but the prerequisite is that there are enough redundant observations, which may not be met in the case of BDS. In addition, it has relatively high time and space complexity. In this study, a priori and effective estimation of variance factors based on the code chipping rate is proposed to properly adjust and determine the observation weights in BDS, thus better characterizing the observation precision while simplifying the calculation. Both static and kinematic experiments were conducted to verify the effectiveness of the new method. The results show that the proposed method is suitable for both open and obstructed environments, and the accuracy and reliability of single point positioning are improved while high efficiency is met.</p></div>","PeriodicalId":22001,"journal":{"name":"Studia Geophysica et Geodaetica","volume":"67 1-2","pages":"39 - 59"},"PeriodicalIF":0.9,"publicationDate":"2023-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4733374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
On the topographic bias by analytical continuation in geoid determination 大地水准面测定中解析延拓的地形偏差
IF 0.9 4区 地球科学
Studia Geophysica et Geodaetica Pub Date : 2023-04-25 DOI: 10.1007/s11200-022-0337-4
Lars E. Sjöberg
{"title":"On the topographic bias by analytical continuation in geoid determination","authors":"Lars E. Sjöberg","doi":"10.1007/s11200-022-0337-4","DOIUrl":"10.1007/s11200-022-0337-4","url":null,"abstract":"<div><p>We consider the topographic bias in gravimetric geoid determination when analytically downward continuing the disturbing potential from the Earth’s surface to sea level. The total bias is subdivided into those of the Bouguer shell or plate and the terrain. In this process, the potential of the Bouguer shell always has a downward continuation bias in the process, which increases with the square of the topographic height and typically exceeds 1–2 cm for elevations higher than 1 km. The main conclusion is that the terrain does not provide a potential bias except possibly for masses located inside a dome of height of about 0.4 times the height of the computation point, and base radius equal to the height of the computation point. This result implies that the potential of all terrain masses of arbitrary density located exterior to the Bouguer shell as well as those outside the dome are unbiasedly downward continued to sea level.</p></div>","PeriodicalId":22001,"journal":{"name":"Studia Geophysica et Geodaetica","volume":"67 1-2","pages":"27 - 38"},"PeriodicalIF":0.9,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11200-022-0337-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5316535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The gravitational potential and its first- and second-order partial derivatives of an ellipsoidal tesseroid based on the Cartesian integral kernel 基于笛卡尔积分核的椭球曲面引力势及其一阶和二阶偏导数
IF 0.9 4区 地球科学
Studia Geophysica et Geodaetica Pub Date : 2023-03-21 DOI: 10.1007/s11200-022-0344-5
Shuai Wang, Zhaoxi Chen, Longjun Qiu
{"title":"The gravitational potential and its first- and second-order partial derivatives of an ellipsoidal tesseroid based on the Cartesian integral kernel","authors":"Shuai Wang,&nbsp;Zhaoxi Chen,&nbsp;Longjun Qiu","doi":"10.1007/s11200-022-0344-5","DOIUrl":"10.1007/s11200-022-0344-5","url":null,"abstract":"<div><p>Gravity forward modelling is a fundamental problem in the fields of geophysics and geodesy at regional and global scales. Considering the curvature of the Earth, tesseroids are suitable to accurately simulate the theoretical gravity field. In general, the spherical tesseroid is regarded as an ideal model, but it cannot consider the oblateness of the Earth. Therefore, we define an ellipsoidal tesseroid at the local Cartesian coordinate system. Then we propose the formulas of the gravitational potential and its first- and second-order partial derivatives of the ellipsoidal tesseroid based on the Cartesian integral kernel. To enhance the practicality, we approximate the ellipsoidal tesseroid to the spherical tesseroid and derive the formulas of the gravitational potential and its partial derivatives. Moreover, we discuss the formulas of the gravity field for the model with linear variable density. The ellipsoidal tesseroid, which is selected as the fundamental mass element, can more accurately simulate the gravity and gravity gradient anomalies of the Earth. Compared with methodologies that make use of integral kernels expressed in spherical coordinate system, the formulas based on the Cartesian integral kernel are given in compact and computationally attractive form. Besides, these formulas can avoid the polar singularity of the spherical coordinate system. The numerical simulation and comparison with previous methods validate the new ellipsoidal tesseriod formulas.</p></div>","PeriodicalId":22001,"journal":{"name":"Studia Geophysica et Geodaetica","volume":"67 1-2","pages":"1 - 26"},"PeriodicalIF":0.9,"publicationDate":"2023-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11200-022-0344-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4829781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Magnetic susceptibility in soil pedons developed on different parent rocks in Kerman province (Iran) 伊朗克尔曼省不同母质岩石发育的土壤土墩磁化率
IF 0.9 4区 地球科学
Studia Geophysica et Geodaetica Pub Date : 2023-01-11 DOI: 10.1007/s11200-021-0771-8
Elham Soleimani Sardoo, Mohammad Hady Farpoor, Majid Mahmoodabadi, Azam Jafari
{"title":"Magnetic susceptibility in soil pedons developed on different parent rocks in Kerman province (Iran)","authors":"Elham Soleimani Sardoo,&nbsp;Mohammad Hady Farpoor,&nbsp;Majid Mahmoodabadi,&nbsp;Azam Jafari","doi":"10.1007/s11200-021-0771-8","DOIUrl":"10.1007/s11200-021-0771-8","url":null,"abstract":"<div><p>Lithology and soil formation affect magnetic susceptibility and its distribution along soil pedons. Kerman province in Iran is typical for variable lithology. However, only limited data on soil magnetic susceptibility in this province and its relation to the lithology are available. We investigate the effect of soil properties and processes on magnetic susceptibility values of soils with different geology in central Iran. Seven soil pedons with different lithology including sedimentary and igneous bedrocks were selected in arid and semi-arid parts of northern Kerman. Routine physical and chemical properties, different forms of iron, and mass-specific magnetic susceptibility values were measured in all the collected samples. Four selected samples underwent magnetic separation. Two of them, which yielded the highest amount of magnetically extracted material, were subjected to X-ray diffraction analysis. In addition, polished sections from the sample with the highest mass-specific magnetic susceptibility were prepared. The results show that lithology strongly affects the magnetic susceptibility in the studied soils, ranging from the minimum value of 4.3 × 10<sup>−8</sup> m<sup>3</sup> kg<sup>−1</sup> (in the soils developed on Cretaceous marls and limestone) to 1264 × 10<sup>−8</sup> m<sup>3</sup> kg<sup>−1</sup> (on andesite rocks). Frequency-dependent susceptibility values of soils (from 0 to 5.3%) showed that coarse multi domain grains inherited from parent material were the main source of magnetism in the area under study. The average amount of free, non-crystalline, crystalline, and active iron oxides in the studied samples were 0.5, 9.96, 8.45, and 0.05 g kg<sup>−1</sup>, respectively. The weighted mean for different factors was calculated in three depth ranges. Slope of linear regression was used to investigate the relation between mass-specific susceptibility and physicochemical parameters for different soil depths. The argilluviation process caused a decrease in the magnetic susceptibility in moderately developed soils of the region. The highest magnetic susceptibility values were found for Cambic Calcisols, followed by the Abruptic Solonetz, both developed on the andesite and gypsiferous marl. A positive relationship between magnetic susceptibility and Fe<sub>o</sub>, Fe<sub>d</sub> and Fe<sub>d</sub> — Fe<sub>o</sub>, and a negative correlation between magnetic susceptibility and Fe<sub>o</sub>/Fe<sub>d</sub> were found. According to X-ray diffraction analyses, diamagnetic minerals are dominant, while antiferromagnetic minerals are rare. The results suggest that changes in the magnetic susceptibility values are highly affected by the processes of soil formation, lithology, and soil classification.</p></div>","PeriodicalId":22001,"journal":{"name":"Studia Geophysica et Geodaetica","volume":"67 1-2","pages":"83 - 106"},"PeriodicalIF":0.9,"publicationDate":"2023-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4460958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Numerical simulation and time-frequency analysis of borehole acoustic logging in fractured formations 裂缝性地层声波测井数值模拟及时频分析
IF 0.9 4区 地球科学
Studia Geophysica et Geodaetica Pub Date : 2023-01-11 DOI: 10.1007/s11200-021-1145-y
Min Xiang, Ran An, Xinghua Qi
{"title":"Numerical simulation and time-frequency analysis of borehole acoustic logging in fractured formations","authors":"Min Xiang,&nbsp;Ran An,&nbsp;Xinghua Qi","doi":"10.1007/s11200-021-1145-y","DOIUrl":"10.1007/s11200-021-1145-y","url":null,"abstract":"<div><p>Currently, using the finite difference method to simulate millimeter-sized fractures in formations requires intensive calculations. However, only the time domain characteristics of the calculated borehole acoustic signal are often analysed, while the frequency domain characteristics are ignored. This study aims to obtain the time-frequency characteristics of full acoustic waveforms in different types of fractured formations while reducing operational time and to analyze more comprehensively the influence of fractures on time-frequency characteristics. Therefore, the variable grid finite difference method is used to simulate full acoustic waveforms in boreholes in formations with millimeter-sized horizontal fractures to reduce the computational time of the finite difference method. Afterwards, the wavelet transform is used to analyze the influence of fracture width, fracture number, and radial extension length on the waveform time-frequency characteristics. The results show that with increasing fracture width or number, the P- and S-wave arrival times are delayed, amplitude attenuation is enhanced, and the dominant frequency increases gradually. The frequency and amplitude attenuation of each Stoneley wave component also increases, and the arrival time of the 20–28 kHz high-frequency Stoneley wave is delayed. When the fracture radial length is limited, an increase in radial length delays the P- and S-wave arrival times, and the amplitude attenuation increases. The main S-, Stoneley, and pseudo-Rayleigh wave frequencies increase, and the Stoneley wave and pseudo-Rayleigh wave amplitude attenuation increases. When the fracture radial length is infinite, the P-wave and pseudo-Rayleigh wave amplitude attenuation increases, whereas that of the S-wave and Stoneley wave decreases. This study reveals the influence of fractures on the time-frequency characteristics of full acoustic waveforms in boreholes, provides a theoretical basis for the time-frequency analysis of full acoustic waveforms, and is significant for further clarification of the propagation characteristics of borehole acoustic waves in fractured formations.</p></div>","PeriodicalId":22001,"journal":{"name":"Studia Geophysica et Geodaetica","volume":"67 1-2","pages":"60 - 82"},"PeriodicalIF":0.9,"publicationDate":"2023-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11200-021-1145-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4460955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
New methods for numerical evaluation of ultra-high degree and order associated Legendre functions 超高次阶相关勒让德函数数值计算的新方法
IF 0.9 4区 地球科学
Studia Geophysica et Geodaetica Pub Date : 2022-11-14 DOI: 10.1007/s11200-022-0830-9
Mehdi Goli, Ismael Foroughi, Pavel Novák
{"title":"New methods for numerical evaluation of ultra-high degree and order associated Legendre functions","authors":"Mehdi Goli,&nbsp;Ismael Foroughi,&nbsp;Pavel Novák","doi":"10.1007/s11200-022-0830-9","DOIUrl":"10.1007/s11200-022-0830-9","url":null,"abstract":"<div><p>We improve the precision and computation speed of the fully-normalized associated Legendre functions (fnALFs) for ultra-high degrees and orders of spherical harmonic transforms. We take advantage of their numerical behaviour of and propose two new methods for solving an underflow/overflow problem in their calculation. We specifically discuss the application of the two methods in the fixed-order increasing-degree recursion computation technique. The first method uses successive ratios of fnALFs and the second method, called the Midway method, starts iteration from tiny initial values, which are still in the range of the IEEE double-precision environment, rather than from sectorial fnALFs. The underflow/overflow problem in the successive ratio method is handled by using a logarithm-based method and the extended range arithmetic. We validate both methods using numerical tests and compare their results with the X-number method in terms of precision, stability, and speed. The results show that the relative precision of the proposed methods is better than 10<sup>−9</sup> for the maximum degree of 100000, compared to results derived by the high precision Wolfram’s Mathematica software. Average CPU times required for evaluation of fnALFs over different latitudes demonstrate that the two proposed methods are faster by about 10–30% and 20–90% with respect to the X-number method for the maximum degree in the range of 50–65000.</p></div>","PeriodicalId":22001,"journal":{"name":"Studia Geophysica et Geodaetica","volume":"66 3-4","pages":"81 - 97"},"PeriodicalIF":0.9,"publicationDate":"2022-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11200-022-0830-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4588984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Hybrid geoid model over peninsular Malaysia (PMHG2020) using two approaches 使用两种方法的马来西亚半岛混合大地水准面模型(PMHG2020)
IF 0.9 4区 地球科学
Studia Geophysica et Geodaetica Pub Date : 2022-11-14 DOI: 10.1007/s11200-021-0769-2
Muhammad Faiz Pa’suya, Ami Hassan Md Din, Ramazan Alpay Abbak, Mohammad Hanif Hamden, Nornajihah Mohammad Yazid, Mohamad Azril Che Aziz, Mohd Adhar Abd Samad
{"title":"Hybrid geoid model over peninsular Malaysia (PMHG2020) using two approaches","authors":"Muhammad Faiz Pa’suya,&nbsp;Ami Hassan Md Din,&nbsp;Ramazan Alpay Abbak,&nbsp;Mohammad Hanif Hamden,&nbsp;Nornajihah Mohammad Yazid,&nbsp;Mohamad Azril Che Aziz,&nbsp;Mohd Adhar Abd Samad","doi":"10.1007/s11200-021-0769-2","DOIUrl":"10.1007/s11200-021-0769-2","url":null,"abstract":"<div><p>We describe the development of a hybrid geoid model for Peninsular Malaysia, based on two approaches. The first approach is utilising an ordinary method fitting the gravimetric geoid to the geometric undulation derived from GNSS-levelling data; the second approach directly fits the gravimetric geoid to the reference mean sea level derived from the tide measurements of Port Klang tide gauge station. The hybrid geoid model fitted to Port Klang (PMHGG2020_PK) is produced by adding an offset of 0.446 m to the gravimetric geoid, based on the comparison at the tide gauge benchmark. To calculate the gravimetric geoid, a new model for Peninsular Malaysia (PMGG2020) has been developed based on Least-Squares Modification of Stokes’ Formula with Additive correction (LSMSA). Three different sources of gravity data which are terrestrial, airborne, and satellite altimetry-derived gravity anomaly (DTU17) have been combined to construct the geoid model. The height information has been extracted from the newly released global digital elevation model, TanDEM-X DEM. GO_CONS_GCF_2_SPW_R4 model derived from GOCE data provides long-wavelengths gravity field up to maximum degree and order 130. The gravity datasets are gridded by 3D Least-Squares Collocation method. The PMGG2020 model is consistent with the geometric geoid heights from 173 GNSS-levelling measurements, with a standard deviation of ±5.8 cm. Evaluation of the hybrid geoid model constructed from the first approach shows a significant improvement over the two existing hybrid geoid models. The accuracy of ±4.6 cm has been achieved after evaluating by 20 GNSS-levelling points, externally. Hybrid geoid model fitted to Port Klang has also been evaluated via 173 GNSS-levelling points, and the result shows that 71% of the total data exhibit height differences lower than 10 cm. The overall results indicate that the hybrid geoid model developed in this study can be valuable as an alternative to the current modern height system in Peninsular Malaysia for surveying and mapping.</p></div>","PeriodicalId":22001,"journal":{"name":"Studia Geophysica et Geodaetica","volume":"66 3-4","pages":"98 - 123"},"PeriodicalIF":0.9,"publicationDate":"2022-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11200-021-0769-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4590991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Regionally adjusted ground motion model: Case study of the ML6.2 (Mw6.4) Petrinja (Croatia) 2020 earthquake 区域调整地面运动模型:以2020年克罗地亚佩特里尼亚ML6.2 (Mw6.4)地震为例
IF 0.9 4区 地球科学
Studia Geophysica et Geodaetica Pub Date : 2022-11-14 DOI: 10.1007/s11200-022-0914-6
Jakov Stanislav Uglešić, Filip Skendrović, Iva Lončar, Snježana Markušić, Davor Stanko
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