Tsunami and its Hazard in the Indian and Pacific Oceans: Introduction -- The 26 December 2004 Sumatra Tsunami: Analysis of Tide Gauge Data from the World Ocean Part 1. Indian Ocean and South Africa -- Quantification of Hydrophone Records of the 2004 Sumatra Tsunami -- Seismic Records of the 2004 Sumatra and Other Tsunamis: A Quantitative Study -- M TSU : Recovering Seismic Moments from Tsunameter Records -- The Tsunami of 26 December, 2004: Numerical Modeling and Energy Considerations -- Field Survey of Tsunami Effects in Sri Lanka due to the Sumatra-Andaman Earthquake of December 26, 2004 -- Field Signatures of the SE-Asian Mega-Tsunami along the West Coast of Thailand Compared to Holocene Paleo-Tsunami from the Atlantic Region -- Eyewitness Accounts of the Impact of the 1998 Aitape Tsunami, and of Other Tsunamis in Living Memory, in the Region from Jayapura, Indonesia, to Vanimo, Papua New Guinea -- Phases Representing Source Lengths of Tsunami in Tide Gauge Records -- Numerical Simulations of Tsunami Waves and Currents for Southern Vancouver Island from a Cascadia Megathrust Earthquake -- Overview of Holocene Tsunami Deposits along the Nankai, Suruga, and Sagami Troughs, Southwest Japan -- Micromorphological Analysis of Coastal Sediments from Willapa Bay, Washington, USA: A Technique for Analysing Inferred Tsunami Deposits -- Volcanogenic Tsunamis in Lakes: Examples from Nicaragua and General Implications -- Estimation of Tsunami Hazard in New Zealand due to South American Earthquakes -- Tsunami Assessment for Risk Management at Nuclear Power Facilities in Japan -- Logic-tree Approach for Probabilistic Tsunami Hazard Analysis and its Applications to the Japanese Coasts -- Conditional Probability Approach of the Assessment of Tsunami Potential: Application in Three Tsunamigenic Regions of the Pacific Ocean -- Steps Towards the Implementation of a Tsunami Detection, Warning, Mitigation and Preparedness Program for Southwestern Coastal Areas of Mexico -- A Study of Tsunami Wave Fission in an Undistorted Experiment. Tsunamis like the Indian Ocean tsunami caused by the Sumatra-Andaman earthquake in 2004 or the Chilean earthquake in the Pacific Ocean in 1960 motivate international collaborations for the development of tsunami warning systems. Since 1960 the Tsunami Commission, established by the International Union of Geodesy and Geophysics, has been holding a biannual International Tsunami Symposium (ITS). This volume contains 20 contributions of leading scientists mostly presented at the 22nd International Tsunami Symposium held in summer 2005 in Greece. Consolidated findings based on hydrophone records, seismometer readings, and tide gauges are presented. Reports of post-tsunami surveys and numerical simulations for tsunamis such as the 2004 Indian Ocean event, as well as geological studies of tsunamis in Japan, Central and North America are given. Probabilistic tsunami hazard analysis and tsunami warning systems, among others, are described as are methods to predict tsunamis and mitigate their hazards.