Contents: Introduction/Sujit Dasgupta. I. Earthquake: 1. A preliminary report on investigation of effects of the Sumatra - Andaman Earthquake of 26 December 2004 in Andaman and Nicobar Islands/K.N. Mathur, S.K. Ray, S. Sengupta, Prabhas Pande and Sujit Dasgupta. 2. Macroseismic survey in Andaman and Nicobar Island in the aftermath of the great earthquake of 26 December 2004/A.K. Ghosh Roy, S. Bardhan, P. Jana and S.R. Basir. 3. Analysis of satellite data for detection of changes in coastal geomorphology of Andaman - Nicobar Islands due to 26 December 2004 earthquake/D.P. Das, S.S. Ghosh, D. Chakraborty and K. Pramanik. 4. 26 December 2004 earthquake: coseismic vertical ground movement in the Andaman Islands/Sumit Kumar Ray and Anshuman Acharyya. 5. Bathymetry and magnetic observations along Andaman Arc-Trench gap in the post-earthquake scenario of 26 December 2004/R. Sengupta and 12 others. 6. Seismotectonics of the Andaman - Nicobar region: constraints from aftershocks within 24 hours of the great 26 December 2004 earthquake/Sujit Dasgupta, Basab Mukhopadhyay and A. Acharyya. 7. Aftershock investigation of the 26 December 2004 Sumatra-Andaman Islands earthquake/O.P. Mishra, G.K. Chakraborty and O.P. Singh. II. Tsunami: 8. Tsunami survey in the Andaman-Nicobar group of Islands/T. Ghosh, P. Jana, T.S. Giritharan, S. Bardhan, S.R. Basir and A.K. Ghosh Roy. 9. Tsunami survey in the Srikakulam-Pulicat segment, Andhra Pradesh/M. Raju, B.K. Bhandaru, V. Singaraju and B.M. Shah. 10. Tsunami survey in the Chennai - Nagapattinam segment, Tamil Nadu coast/R. Srinivasan and K. Nagarajan. 11. Tsunami survey in the Nagapattinam - Kanyakumari segment, Tamil Nadu coast/B. Kanishkan and B. Lakshminarayanan. 12. Tsunami survey in the Kanyakumari - Cochin segment in parts of Tamil Nadu and Kerala/K. Jayabalan and U. Durairaj. Appendix I: Locality index.