Identifying the most explainable fault ruptured of the 2018 Palu-Donggala earthquake in Indonesia using coulomb failure stress and geological field report

This study investigates the relation between the Coulomb failure stress of the mainshock with the aftershocks sequence following the 2018 Palu-Donggala earthquake in Indonesia.We calculate the Coulomb failure stress using the available coseismic fault models,which had varied moment magnitudes between M_W7.53~M_W7.62.Different interpretations of the fault sources were suggested by previous studies.While two fault models suggested that one inland fault segment ruptured during the earthquake,another fault model proposed that two fault segments ruptured inland of Central Sulawesi and along the coast of Palu bay.We further overlay the positive and negative values of Coulomb failure stress with the reported relocated aftershock.We find that only by conducting Coulomb failure stress analysis,we can not favour the preference of the coseismic fault which explains aftershock distribution.This investigation demonstrates that additional observational data from geological field surveys are required to identify the surface rupture in comparison with the coseismic fault model.

THE CHARACTERISTICS OF GEOLOGICAL GENERAL FIELD OF VOLCANIC BELT IN LANCANG RIFT VALLEY AND ITS SIGNIFICANCE FOR EXPLORATION

Based on the theory of dissipative structures and moving character-parameters of elements,this paper examines the characteristics of the geological general field of volcanic belt in the Lancang rift valley,west Yunnan,China-with an open system and lower pressure environment,the volcanic belt is characterized by a large scale continuously graduating dissipative structure and three orders of concentrated minerogenetic material fields,and by the energy fields that influence the time and space structure of material fields.The research shows that the third order minerogenetic material fields which surround volcanic eruptive centers and have hydrothermal superposition and reconstruction after the magma stage possess favorable prognosis targets for copper polymetal.

Spatial data modeling for coalfield geological environment

Presented a study on the design and implementation of spatial data modelingand application in the spatial data organization and management of a coalfield geologicalenvironment database.Based on analysis of a number of existing data models and takinginto account the unique data structure and characteristic, methodology and key techniquesin the object-oriented spatial data modeling were proposed for the coalfield geological environment.The model building process was developed using object-oriented technologyand the Unified Modeling Language (UML) on the platform of ESRI geodatabase datamodels.A case study of spatial data modeling in UML was presented with successful implementationin the spatial database of the coalfield geological environment.The modelbuilding and implementation provided an effective way of representing the complexity andspecificity of coalfield geological environment spatial data and an integrated managementof spatial and property data.

Theory of Geological Anomaly in Remote Sensing

Geological anomaly is geological body or complex body with obviously different compositions, structures or orders of genesis as compared with those in the surrounding areas. Geological anomaly, restrained by the geological factors closely associated with ore forming process, is an important clue to ore deposits. The geological anomaly serves as a geological sign to locate ore deposits. Therefore, it is very important to study how to define the characteristics of geological anomaly and further to locate the changes in these characteristics. In this paper, the authors propose the geological anomaly based on the remote sensing images and data, and expound systematically such image features as scale, size, boundary, morphology and genesis of geological anomalies. Then the authors introduce the categorization of the geological anomalies according to their geneses. The image characteristics of some types of geological anomalies, such as the underground geological anomaly, are also explained in detail. Based on the remote sensing interpretation of these geological anomalies, the authors conclude that the forecasting and exploration of ore deposits should be focused on the following three aspects: (1) the analysis of geological setting and geological anomaly; (2) the analysis of circular geological anomaly, and (3) the comprehensive forecasting of ore deposits and the research into multi source information.

Gravity gradient distribution in China's Mainland from GOCE satellite gravity gradiometry data

At present, gravity field and steady-state ocean circulation explorer（GOCE） gravity data are always used to compute regional gravity anomaly and geoid height. In this study, the latest GOCE gravity field model data（from Oct. 2009 to Jul. 2010） are used to compute the gravity gradient of China's Mainland according to a rigorous recursion formula（in all the six directions）. The results show that the numerical values of the gravity gradients are larger in the T rr direction than those in the other directions. They reflect the terrain characteristics in detail and correlate with the regional tectonics; however, in the T ql and T r l directions,the numerical values are relatively smaller and the gravity gradients in the T r l direction do not reflect the terrain characteristics in detail.