Preface

Preface

The satellite remote sensing technique has emerged as a powerful tool in recent years in mapping changes on land and land cover after various kinds of natural hazards. In recent years, the remote sensing technique has developed significantly in monitoring earth at larger to smaller scale in terms of hundred kilometres to few metres. The use of broadband wavelengths has provided the remote sensing community with a tool to exploit its applications in mapping multiple parameters of land, ocean and atmosphere. Numerous countries have initiated space science programmes and also planned to launch satellites to have detailed information about the landuse and land cover, natural resources and information about weather conditions. Using these satellites, one can get information about the changes throughout the globe within one hour to several days depending upon the objectives.

The application of satellite remote sensing data has been used in a very limited manner in order to map the damages after natural hazards such as floods, earthquakes, landslides, forest fires, cyclones/hurricanes, etc. for a long time. Uses of multi sensor data in a broad, visible to microwave, wavelength range have opened a new era in the management of natural hazards. For the first time, scientists made efforts to exploit multi‐sensor data to study the changes in land, ocean and atmospheric parameters associated with the Gujarat earthquake that occurred on 26 January 2001. Numerous studies, using optical and microwave remote sensing data, have provided information on the damages that were caused by the earthquake and also changes on land, ocean and atmospheric parameters associated with the deadly Gujarat earthquake which took 20 000 lives and million dollar properties. These studies have also given evidence based on multi‐sensor optical and microwave data that the land, ocean and atmospheric changes prior to the earthquake in the epicentral region of the earthquake. After the Gujarat earthquake, the remote sensing community made serious efforts to use remote sensing data to study changes associated with major earthquakes throughout the globe. These efforts have given evidence about the strong coupling between land–ocean–atmosphere–ionosphere associated with earthquakes of magnitudes of more than 5.5 occurring up to a focal depth of 35 km. Scientists believe that the continuous monitoring of land, ocean and atmospheric parameters in the seismically active regions of the world using multi‐satellites sensors are likely to provide early information about an impending disastrous earthquake.

Soon after the occurrence of the mega Sumatra earthquake (magnitude 9.3) of 26 December 2004 which took more than 200 000 lives and affected people living along the coastal regions of Indonesia, Thailand, India, Bangladesh, Malaysia, Myanmar, Sri Lanka and Maldives, remote sensing images showing damages and changes in the land patterns were seen by people in the local, national and international newspapers and on television. These images clearly showed the changes along the coastal regions, water logging, ocean wave pattern, loss of vegetation and forests along the coasts. Using remote sensing data, estimates of loss due to the mega Sumatra earthquake were made. Advantage of optical and microwave remote sensing data from various remote sensing satellites was also taken to quantify the changes in land and ocean temperature, atmospheric and ocean parameters, wave height and wind parameters and also in ionospheric parameters. This Special Issue of the International Journal of Remote Sensing provides a set of 18 research papers dealing with satellite remote sensing and ground observations of land, ocean, atmosphere and ionosphere associated with the Sumatra tsunami. The research papers provide information on the advancement of satellite observations over the epicentral and surrounding regions of the deadly earthquake of 26 December 2004. The research papers demonstrate the potential of satellite observations associated with the Sumatra earthquake and also show significant changes of few parameters prior and after the earthquake. Some of these parameters, if monitored properly, may prove to provide early information about an impending earthquake. Some of the papers included in this Special Issue show the application of remote sensing data for accurate estimation of crustal movements and ocean wave height and changes in the atmospheric and ionospheric parameters. This Special Issue provides a detailed account of damages and changes associated with the Sumatra earthquake observed from satellite data.

I would like to thank the authors for their scientific contributions, to Professor Arthur Cracknell for encouragement in bringing this Special Issue to fruition and to Ms Catherine Murray for providing technical support in handling the manuscripts. Additionally, I would like to thank the manuscript reviewers for providing valuable comments and suggestions to the authors that helped greatly in improving the quality of the papers.