How GIS and Remote Sensing could have helped in the Gujarat disaster

How GIS and Remote Sensing could have helped in the Gujarat disaster

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Ajay Lavakare

Could the GIS technology have been used more effectively to save some of the lives that were snuffed out and to have reduced the damage caused to property and facilities?

The magnitude 8 earthquake that struck Gujarat on the morning of January 26th, 2001, and that has killed over 20,000 people and caused estimated damages to the tune of Rs. 15,000 crore, has once again forced the GIS community in India to introspect. To ask ourselves the question – could this technology have been used more effectively to save some of the lives that were snuffed out and to have reduced the damage caused to property and facilities? And to ask an even more important question – can the technology be used to reduce or prevent loss of life, property and infrastructure in future disasters?

This article attempts to describe a few of the application of GIS and remote sensing technologies that could have been used before, during and after the Gujarat earthquake, and also infers how it could be used for mitigation in future disaster scenarios.


Fig 1: Affected transport network mapped using GIS

Role of GIS and Remote Sensing in Pre Disaster Planning
One of the most common tools used in pre-disaster planning by government and disaster management planners is Hazard mapping. “Hazard” is a measure of the physical intensity of the peril (in this case earthquake) at a particular location and the associated probabilities of these intensities. Some of the types of maps useful for hazard mapping include: active fault maps, location of past earthquake events and their impact, seismic zonation and micro-zonation maps, soil and geology maps, etc. These maps can be generated by traditional means such as field surveys, and supplemented by remote sensing analysis. From these map data sets and additional geographic data sets such as terrain and water table levels, additional hazard maps can be generated using GIS functionality, such as liquefaction potential and landslide susceptibility maps. In most earthquake-prone developed nations, hazard mapping is undertaken at the county (or district) level and is an on-going activity. Typically, hazard maps are generated in a GIS through partnerships between local governments, government mapping agencies, and the engineering consulting companies. The hazard maps are then disseminated to the local population, not only through traditional means such as the media but also by publishing them on the Internet and allowing public access to this GIS data.

In India, most of the fundamental data sets required for hazard mapping are available, but at low resolutions. Also, these data sets are held by different government or engineering organisations and rarely if ever disseminated even within their organisation, much less to the public at large. Small-scale hazard maps for the entire country, showing seismicity and active faults, can be purchased from agencies like NATMO, but in order to be useful, these maps need to be developed at the district level, at scales of at least 1:100,000, in order to be really useful.


Fig 2: Map created using GIS showing the epicentre, active faults and geology of the epicentral region

The power of a GIS in pre-disaster planning is heightened when these hazard maps are super-imposed with mapping of infrastructure and lifelines. These include mapping of water supply lines, bridges, transportation, telecommunication, and power networks, as well as critical facilities such as hazardous material locations, power generating plants, refineries, ports, etc. Remote sensing and photogrammetry techniques can be easily applied to generate or update these maps. By looking at these super-imposed data sets, planners can immediately identify the areas that would be worst impacted in an earthquake, and plan their emergency response activities accordingly.

Had hazard maps of Gujarat been available to planners, engineers, and the public at large, there would have been greater awareness of the fact that the area is indeed earthquake prone with a high hazard score. The government could have focused its efforts on educating the population on how to react and respond during an earthquake. Builders may have been more careful about adhering to the building code, and inspections and approvals of plans may have been slightly more stringent. In fact, one of the reasons that large earthquakes in countries like Japan and the United States do not kill as many people is because of the high level of awareness that the planners, builders, developers and the population have, resulting in people taking adequate precautions in their daily lives as well as during an event. It would have also been more apparent to central planners that an earthquake in a highly industrialised region of Gujarat could have far-reaching economic implications, since the mapping of infrastructure and lifelines in Gujarat would show that hazard prone regions of the state are also the heart of Indian industries such as petroleum, power and steel.

Another GIS-based tool used in pre-disaster management is Vulnerability Mapping. Vulnerability mapping for Gujarat would have included documentation of the building stock, identification of vulnerable areas based on the demographic details and the building types in Gujarat. A Vulnerability Atlas of India has been developed, but this work has not received the attention it deserves, not has it been disseminated to the public at large. I believe many of the maps in the atlas were generated digitally from a GIS, and could have lent themselves to easy dissemination. An understanding of vulnerability, through vulnerability maps, would have allowed owners of property and infrastructure in Gujarat to seek appropriate insurance coverage against earthquake. It would also have helped alert builders to the criticality of adhering to building codes and focussed their attention to the seismic-proofing details in their designs. It would also have allowed insurance companies to price their policies appropriately, and seek adequate levels of re-insurance.


Fig 3: A short segment of the fault that was mapped and recorded using GPS

Lastly, there has been a lot of work done internationally in the area of loss estimation methodologies, using comprehensive GIS data sets with engineering models. The United States government commissioned the development of a standardised earthquake loss estimation methodology called HAZUS, (developed by RMSI) and has made this system available to regional planners in counties. Using this software application, planners can carry out “what-if” scenario analyses. They can simulate the likely impact of scenario events. This helps them in assessing the possible impact of such an event including direct and indirect economic losses. The knowledge to develop similar models for India is available with us. What are missing are the consolidated and reliable data sets that are needed as the base of the models, along with the funding to build these models for at least the most earthquake prone regions of the country. Role of GIS and Remote Sensing in post disaster scenario The power of GIS and remote sensing can be used to save lives in a post-disaster scenario, by providing decision support in prioritising relief efforts and by helping relief crews get to affected areas in a timely manner. It can also help provide people made destitute by an earthquake with quicker relief, in the form of relocation planning and quick settlement of damage claims. When an earthquake strikes, the first question on everyone’s lips is – where did it strike; followed by the question – how widespread is the impact and the damage (loss of lives and property).

Using aerial photography, affected regions can be quickly identified and the photographs and maps generated from them used to quickly communicate the areas and extent of damage to the relief crews. These maps generated from aerial photos would provide a spatial coverage of the damaged areas, identifying the worst affected regions to prioritise the relief efforts; for example – mapping of the earthquake intensity, and casualties, industrial damage etc. in the affected areas in Gujarat

While relief crews are rushed to the affected areas, they, as well as their controlling command centres are hampered by the fact that they are usually unfamiliar with the affected areas. They can use GIS based applications for transport and logistics planning – GIS based application with the latest information on alternate routes, and the demographics of the affected area can be used by all the agencies to coordinate their efforts in a more effective manner. For example, many of the roads were damaged in and around the Bhuj area, seriously hampering the relief efforts. A mapping of the affected roads, and alternatives could have been very helpful in getting rescue and relief teams to the devastated areas in a more timely manner. A recent case study also illustrates how GIS was actually deployed in the post-disaster scenario of the Gujarat earthquake. A team of international disaster management experts from Japan, USA and UK, comprising of seismologists, earth scientists, civil and earthquake engineers were planning a reconnaissance visit to Bhuj and other areas to gather as much information about the event before that information got destroyed over time. The information that they were particularly seeking was related to geo-technical data such as liquefaction and fault trace that will erode away with time and damaged buildings that will be either retrofitted or demolished. In order to assist the team in their reconnaissance planning, RMSI quickly put all the available maps and satellite imagery of the region in to a GIS workspace and provided access to this workspace over the web, allowing the team members living in different countries to quickly familiarise themselves with the geography, terrain, seismicity and geology of the area. Working from data from the GIS including satellite imagery and published geological studies of the region, the team was able to locate in the field traces of the fault that they believe may have generated the earthquake. At this time, only a short segment of the fault that may extend tens of kilometers has been mapped and recorded through Global Positioning System (GPS). This segment is located near the village of Budarmora 53 km east of Bhuj and 16 km west of Bhachau. GIS could also be used as a support tool for relocation planning. The GIS could be queried for identification of alternative sites for relocating people rendered homeless by the quake. This would require reliable information on demographics, terrain, and location of the “lifelines” like water supply and transportation networks, to be readily available in the GIS, so that various alternatives for relocation could be evaluated and the best option(s) selected.

Conclusions
The Indian GIS industry comprising of the private sector, government, academia and media, is amongst the most vibrant and advanced GIS industries in Asia. Many of us have worked on and developed applications of GIS and remote sensing in disaster management for regions around the world, and have the satisfaction of knowing that these applications are being used to save lives and money. What is ironical is that very few of us have the satisfaction of saying that these applications are being developed or used to save lives and money in our own country.

I am pretty certain that GIS technologies were grossly under-utilised, if utilised at all, during and post disaster in Gujarat. I do hope however, that we all finally learn our lessons from this tragedy, and put to use the technologies that we have mastered, for the benefit of our own people.