Global Service Definition Document

The Global Service Definition Document (GSDD) describes global tsunami warning services that are provided by regional tsunami warning systems operating in different ocean basins as a global system of systems and coordinated by the Intergovernmental Oceanographic Commission of UNESCO (UNESCO-IOC). The document also provides guidance for global harmonisation of tsunami watch operations.

This document is prepared by the Task Team on Tsunami Watch Operations (TTTWO) established by the Working Group on Tsunamis and Other Hazards related to Sea-Level Warning and Mitigation Systems (IOC/TOWS-WG). This is intended to be a living document that will undergo additions and modifications as finalized by the TTTWO from time to time as it works towards global harmonization of tsunami watch operations.

The recommendations put forth in this document are based on best-practice and intend to serve as a broad guidance to the to the Intergovernmental Coordination Groups (ICGs) in different ocean basins in planning and development of their systems. While the specific requirements of each region will continue to drive the evolution of each regional tsunami warning system, following a common framework as put forth in this document will ensure that operations within and among different regional systems become seamless and interoperable.