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Abstract-Tsunamis are high-impact disasters that can cause death and destruction locally within a few minutes of their occurrence and across oceans hours, even up to a day, afterward. Efforts to establish tsunami warning systems to protect life and property began in the Pacific after the 1946 Aleutian Islands tsunami caused casualties in Hawaii. Seismic and sea level data were used by a central control center to evaluate tsunamigenic potential and then issue alerts and warnings. The ensuing events of 1952, 1957, and 1960 tested the new system, which continued to expand and evolve from a United States system to an international system in 1965. The Tsunami Warning System in the Pacific (ITSU) steadily improved through the decades as more stations became available in real and near-real time through better communications technology and greater bandwidth. New analysis techniques, coupled with more data of higher quality, resulted in better detection, greater solution accuracy, and more reliable warnings, but limitations still exist in constraining the source and in accurately predicting propagation of the wave from source to shore. Tsunami event data collected over the last two decades through international tsunami science surveys have led to more realistic models for source generation and inundation, and within the warning centers, real-time tsunami wave forecasting will become a reality in the near future. The tsunami warning system is an international cooperative effort amongst countries supported by global and national monitoring networks and dedicated tsunami warning centers; the research community has contributed to the system by advancing and improving its analysis tools. Lessons learned from the earliest tsunamis provided the backbone for the present system, but despite 45 years of experience, the 2004 Indian Ocean tsunami reminded us that tsunamis strike and kill everywhere, not just in the Pacific. Today, a global intergovernmental tsunami warning system is coordinated under the United Nations. This paper reviews historical tsunamis, their warning activities, and their sea level records to highlight lessons learned with the focus on how these insights have helped to drive further development of tsunami warning systems and their tsunami warning centers. While the international systems do well for teletsunamis, faster detection, more accurate evaluations, and widespread timely alerts are still the goals, and challenges still remain to achieving early warning against the more frequent and destructive local tsunamis.

Airborne volcanic ash is one of the most common, far-travelled, direct hazards associated with explosive volcanic eruptions worldwide. Management of volcanic ash cloud hazards often requires coordinated efforts of meteorological, volcanological, and aviation authorities from multiple countries. These international collaborations during eruptions pose particular challenges due to variable crisis response protocols, uneven agency responsibilities and technical capacities, language differences, and the expense of travel to establish and maintain relationships over the long term. This report introduces some of the recent efforts in enhancing international cooperation and collaboration in the Northern Pacific region.

To enhance the tsunami warning operation system in the Philippines caused by earthquakes in and around the country, staff members of the Japan Meteorological Agency (JMA) joined the SATREPS program in 2012 to help building a tsunami simulation database in the Philippine Institute of Volcanology and Seismology (PHIVOLCS), which storesmultiple results of tsunami simulations such as estimated tsunami arrival times and heights at coasts for multiple hypothetical earthquakes of various hypocenter locations and magnitudes. The procedure to construct a database consists of several steps starting from setting assumed fault parameters and others, proceeding to tsunami simulations and data creation to be stored in the database, and as the last step, creating a searching system which picks results from the database according to the location and magnitude of an earthquake. As of July 2014, the PHIVOLCS has stored the results of tsunami simulations conducted for more than 30,000 assumed faults for local tsunamis. The searching system is also prepared which enables to get a quick grasp of expected tsunami features quantitatively. With this database and the searching system, the PHIVOLCS is in near future to issue initial tsunami warnings based on the information of estimated tsunami arrival times and heights immediately after the hypocenter location and magnitude of an earthquake are determined. When the necessary coordination with related organizations as well as the public education for the system and warning messages are ready, the PHIVOLCS will start the enhanced local tsunami warning operation.