GIS in Geoscience: The recent trends
Potential earth science hazards due to earthquakes include ground motion, ground failure (i.e., liquefaction, landslide and surface fault rupture) and tsunamis. Ground motion is characterised by: (1) spectral response, based on a standard spectrum shape, (2) peak ground acceleration and (3) peak ground velocity. The spatial distribution of ground motion can be determined using one of the following methods such as, deterministic ground motion analysis (methodology calculation), probabilistic ground motion maps and other probabilistic or deterministic ground motion user-supplied maps. Deterministic seismic ground motion demands are calculated for user-specified scenario earthquakes. For a given event magnitude, attenuation relationships are used to calculate ground shaking demand for rock sites which is then amplified by factors based on local soil conditions when a soil map is supplied by the user. IIRS has done such studies for Bhuj with respect to recent earthquake and for Dehradun region with respect to a hypothetical event using ARCVIEW. Peak ground acceleration, liquefaction probability and lateral spreading are calculated and cross-checked with actual liquefaction in Bhuj region. For Dehradun region, different scenarios were built for assessing seismic hazard. Although these studies are very much generalised with respect to data variability, at least one point is highlighted that the role of GIS is obvious in creating such maps. Such maps can be used for calculating intensity and damage in different scenarios using damage assessment methodology such as RADIUS in GIS environment.
Seismicity induced landslides can also be assessed in GIS using parameters such as Intensity; slope steep-ness; strength and engineering properties of geologic materials; water saturation existing landslide areas; and vegetative cover. Various integration techniques for seismic induced landslides like the one given in HAZUS methodology, can be implemented using simple matrix overlay in any GIS package.
In recent years, there has been explosion of GIS applications in geosciences, a simple search command in MSN shows 36,000 items for groundwater and GIS, 52,000 items for mining and GIS, 20,000 items for earthquake and GIS. However, the case studies from Indian region are limited to only a few academic departments and research organisations. The single most important reason being late realisation of the role of GIS in geoscience in India. As a result most of the professional departments either have just started or have yet to institutionalise GIS. Any useful Geoscience GIS needs enormous amount of data which lies only with professional departments, therefore, it is highly essential that such departments take a lead in implementing GIS. The need of the hour is that GIS must be seen as a part of the ERP solution in mineral related industry. Apart from the visualisation, simulation and modeling, GIS based Spatial Decision Support Systems must be explored for geological applications.
Mineral Resource Information System
An attempt has been made to develop a prototype of a “Mineral Resource Information System” to provide all basic information related to mineral deposits of a region in a most cost effective manner. In the present study, Singhbhum-Keonjhar region of Orissa and Jharkhand has been selected, as it is one of the most important iron and manganese-producing belt of India. This area is under mineral exploration since last century and quite a large amount of data is generated.
The MRIS concept is derived from basic GIS concept and the concept of MERIGOLD, a database on gold deposits of Australia. It aims to provide spatial and non-spatial information on iron and manganese deposits and geological set up of the region. Most importantly, the non-spatial data can be edited and saved with latest information.
The information content of the MRIS is divided into three parts: spatial, non-spatial and contextual. The spatial information consists of remotely sensed data and thematic information layers. The remotely sensed data consists of raw and processed data products from various sensors such as IRS-LISS-II, Landsat 5-TM, and ERS-1-SAR (Fig. 1). The thematic information layers consists of lithology, lineaments, mine location, road network, drainage network, DEM, slope, aspect and location map. All such information and data layers are organised using GIS and image processing packages such as ERDAS Imagine 8.4 and ARC GIS 8.1. The non-spatial database is stored in a MS Access file and the contextual information is stored in hyper linked MS Word file. The non-spatial database consists of basic information on deposits, year wise, grade wise production, chemical analysis and mining environment.
Fig. 1: Organisation of spatial data
Fig. 2: Organisation of non spatial data
Software design and implementation
The MRIS is designed in such a way that its concept can be used for other related fields, where input data is spatial or non spatial or both. The information regarding a mine can be obtained through graphics by clicking on the appropriate location or selecting from the adjacent scroll bar, where all mine names are kept in order. Following are the information content and salient features of the prototype MRIS v 1.0 (Fig. 3 and 4).
Fig. 3: Front Page of MRIS v 1.0
Fig. 4: Different options for displaying mining locations and satellite
Application potentials and limitations
- It provides information on geology, mining, production, chemical analysis of ore and rock sample’s, and environmental data (air, water and land).
- User friendly information available on point click or through pull down menu.
- Commercial GIS software independent, however, it can be linked to ARC GIS 8.1 if available.
- Produces report various types of line graphs, bar graphs, etc.
- Database updating possible with password option.
- Context help file contains complete geological information in report form, which can be updated in MS WORD with additional information.
- Software uses mostly Microsoft resources (Access and Word)
- MRIS is developed using Visual Basic 6.0
- System used: P-III and Windows NT
- A software package named as “MRIS version 1.0” is developed with all components including database.
- This can be installed in any Windows NT machine and the full capabilities of the software can be utilised.
- System requirement: 133 MB of disk space with 87 MB space for samples, thus total software installation requires 220 MB for full functionality
The MRIS as visualised can be used for various purposes such as for easy accessibility of geological information, for sharing of geochemical data, in mineral exploration, revenue collection, environmental assessment and management, for mineral customer support, and for research and education purposes. In developmental stage as in the present form, MRIS has various limitations. The database is not complete in many respects due to non-availability of information from mining authorities. The satellite data provided also does not cover completely the study area.
The present attempt has demonstrated that an information system with spatial and non-spatial information can be developed and can be used by clients without expensive commercial GIS packages. In the present case only for preparing spatial data layers, GIS and DIP packages were used, For data access, display, query and updating of non-spatial data, MRIS can be used. The system can be packaged and given to users who can update the database and use it as per their needs. Most importantly, it has highlighted that in the era of software customisation, it is essential that some basic component of any information system should be independent of any GIS package, then there should be gradual entry into the GIS system through customised menu system, and finally most experienced users can be exposed to the GIS system as it is, thereby allowing gradual learning of the spatial information system. Secondly, for most of the basic usage of any information system, investment in terms of GIS infrastructure and GIS training is not mandatory. Thus in every attempt to develop spatial information system, particularly targeting different user groups, it is worthwhile to consider this MRIS philosophy.
Authors are thankful to Dr P S Roy, Dean, IIRS and Prof V K Jha and also to various organisations such as Orissa Mining and Geology Directorate, OMC, SAIL, TISCO, OMDC, IBM and various other private mining owners for providing information and help during field work in Singhbhum-Keonjhar region.