Geodesy for the Sendai Framework

Geodesy for the Sendai Framework


This activity will establish the Geodesy4Sendai Community Activity with its first project: organizing the Global Navigation Satellite System (GNSS) Tsunami Shield Consortium of international organizations to enhance tsunami early warning systems with the unique powerful capabilities of GNSS real time positioning and ionospheric imaging for the GNSS enhancement for Tsunami Early Warning Systems (GTEWS). Through the Geodesy4Sendai activity, the Consortium will implement the recommendations of the GTEWS 2017 workshop as presented within the 2019 Global Assessment Report on Disaster Risk Reduction (GAR19) of the United Nations Office for Disaster Risk Reduction (UNDRR).

The GTEWS 2017 workshop was supported by the eleven nation GATEW working group of the Global Geodetic Observing System, the Association of Pacific Rim Universities (APRU), the  International Research Institute of Disaster Science of Tohoku University, and United States National Aeronautics and Space Administration. The GTEWS 2017 report provides the rationale and strategy to implement Resolution #4 of the 2015 International Union of Geodesy and Geophysics (IUGG) General Assembly. As its first task, Geodesy4Sendai will bring together these supporting organizations, the GEO community and several national real time GNSS networks within the Indo-Pacific and Caribbean basins to establish a prototype GTEWS network to demonstrate the implementation of IUGG 2015 Resolution #4.

This activity was influenced by the objectives and approaches of the Earth Observations for Disaster Risk Management component of the GEO 2017-2019 Work Programme. The application of advanced GNSS real time processing for positioning and ionospheric imaging provides very significant improvements to Tsunami Disaster Early Warning. Furthermore, the GTEWS initiative is in significant alignment with the goals of the Sendai Framework as outlined in the GTEWS supporting paper of the GAR19 report.

Planned Activities

Geodesy4Sendai will work to influence the development of international ministerial level support and financial support for the GTEWS program for the Asia-Pacific and Caribbean economies while also accelerating the development of the GTEWS products to enhance existing and planned tsunami warning systems. These efforts will provide GNSS information to regional tsunami warning systems and national emergency services in formats that are readily assimilated.

Development activities will include:

  • Encouragement of software, data exchange, and continued improvement of GTEW network design and performance.  Geodesy4Sendai will develop protocols for the exchange of real-time GNSS tsunami warning data, the sharing of research results, and the development of support agreements. 
  • Strengthen broadband communication to underserved regions of the GNSS Tsunami Shield. Portions of the prototype GTEWS networks are not connected through real-time communications between receiver and analysis centres. Real-time GTEWS communications requirements can be met with current Fourth Generation wireless technology.
  • Encourage national organizations including those mandated for natural hazards mitigation to develop agreements for inclusion of their GNSS receivers within the GNSS Tsunami Shield. National or agency level restrictions for access to real-time GNSS data is the greatest challenge to the integration of an effective GTEW system.
  • Design an optimal GNSS Tsunami Shield network for both crustal displacement and high-resolution Total Electron Content (TEC) monitoring. The GTEWS 2017 workshop recommended a numerical analysis that includes local geology, seismicity and communications infrastructure. Use existing GNSS sites wherever possible.
  • Understand the operational requirements of existing tsunami warning systems and determine the steps required to interface these tsunami warning systems. GTEWS is an observational and analysis capability that must be integrated with public advisory and warning capability. The rapid and successful implementation of GTEWS will rely upon fluid interactions amongst national agencies.


For more information about the Geodesy for the Sendai Framework please contact GEO Secretariat