Description: A series of severe earthquakes hit Central Chile on Saturday, 27th February 2010. The main shock off Concepcion at 06:34 UTC (3:34 AM local time) had a magnitude of 8.8 Mw. The Pacific Tsunami Warning Center PTWC in Hawaii, USA issued a regional warning at 06:46 UTC (12 minutes after the event). This was the first ocean wide test of a system that was put in place nearly 45 years ago by UNESCO’s Member States through its Intergovernmental Oceanographic Commission (IOC), after a 9.5 magnitude earthquake on 22 May 22 1960 off Chile triggered a wide ocean tsunami that caused 61 fatalities in Hawaii and 142 fatalities in Japan, several hours after the earthquake. As indicated above, 12 minutes after the 27th February 2010 earthquake the Pacific Ocean Tsunami Warning System (PTWS) went into action, with timely and adequate information produced and disseminated across the Pacific Ocean. There were no fatalities reported far from the epicenter, however, near the epicenter off the Chilean coast, official accounts indicate over 156 fatalities due to the tsunami. Preliminary measures of a Rapid Survey Team deployed the week after the event by UNESCO showed run up measurements as high as 30 meters with most common measurements between 6 and 10 meters in the most affected area of the Chilean coast. This earthquake and tsunami event presented an ideal opportunity to assess the performance of the PTWS. To that end the UNESCO/IOC Secretariat for the PTWS sent out a post-event survey questionnaire to the Tsunami Warning Focal Points (TWFPs) and Tsunami National Contacts (TNCs) from its 32 Member States and territories. This report has been prepared by the Secretariat based on the responses received from 19 TWFPs and TNCs. Factual details of the earthquake event and the tsunami are presented and the results of the survey are listed in tables and displayed as timelines and maps. We underscore that all TWFPs received the first PTWC bulletin. In addition, most of the countries reported PTWC as source of awareness of the earthquake. Fourteen countries issued a tsunami warning and in 9 Member States coastal zones were evacuated. It would be pertinent that each Member State analyze if an evacuation would have been necessary in zones where no evacuation was made. In four countries, some areas were evacuated preventively (self-evacuation). Moreover, it was observed that sea level was monitored by most of the countries. In addition, some countries used results from numerical modelling and calculated earthquake parameters. Based on data and information collected from Member States the PTWS acted promptly and efficiently throughout the Pacific. However, and at the same time, this event demonstrated the need to reinforce the work of PTWS for near field events, particularly with denser sea level real time networks close to active subduction areas. Indeed, as it has been demonstrated by the case of the sea level station located in Talcahuano, Chile, sea level stations close to the epicenter may be partially or totally destroyed by the impact of an earthquake and/or a tsunami. Given the critical role sea level readings have in all tsunami warning systems, the sea level monitoring networks should be densified close to active subduction areas and redundancy of sensors and transmission paths be strongly considered. Most of the issues revealed by the survey can be addressed both by the PTWS and at the national level through increased regional cooperation and training where needed. Post-event assessments assist in this process by highlighting the strengths and weaknesses of the PTWS at regional, national and local levels and by raising the awareness of how Member States responded, both individually and collectively. The true value of such assessments is that it allows Member States to share information and experiences for the mutual benefit of improving the PTWS performance for all members.

Description: OpenASFA input

Description: Published

Description: Non Refereed

Description: The 26 December 2004 tsunami in the Indian Ocean killed over 230,000 people, displaced more than 1 million people and left a trail of destruction. Considering that the Caribbean is a region prone to tsunamis, and recognising the need for an early warning system, the Intergovernmental Coordination Group (ICG) for the Tsunami and other Coastal Hazards Warning System for the Caribbean and Adjacent Regions (CARIBE EWS) was established in 2005 as a subsidiary body of the IOC-UNESCO with the purpose of providing assistance to all Member States of the region to establish their own regional early warning system. The main objective of the CARIBE EWS is to identify and mitigate the hazards posed by local and distant tsunamis. The goal is to create a fully integrated end-to-end warning system comprising four key components: hazard monitoring and detection; hazard assessment; warning dissemination; and community preparedness and response. The Pacific Tsunami Warning Centre (PTWC) in Hawaii is the interim tsunami warning service provider for the Caribbean. The West Coast and Alaska Tsunami Warning Centre (WC/ATWC) is providing tsunami warning service for the USA territories in the Caribbean region. The magnitude 7.0 earthquake in Haiti on the 12 January 2010 was one of the most severe earthquakes that occurred in this country in the last 100 years. It caused a large number of casualties and material destruction.In addition, the earthquake generated a tsunami that caused a runup of 3m at both Jacmel and Petit Paradis, Haiti and 1m in Pedernales, Dominican Republic. Furthermore, it was recorded with an amplitude of 12 cm (peak to trough) at the Santo Domingo sea level station in the Dominican Republic. The arrival time was at 22:40 UTC, namely 47 minutes after the earthquake occurred. This tsunami recalled the need to effectively implement the CARIBE EWS to be prepared for future potentially destructive tsunamis in the region. The event therefore presented an ideal opportunity to evaluate the performance of the CARIBE EWS to highlight both the strengths and weaknesses of the system, to identify areas that require further attention, and to provide a benchmark of the present status of the system. The UNESCO IOC Secretariat for the CARIBE EWS sent out a post-event survey questionnaire to Member States and territories that have identified their Tsunami Warning Focal Points (TWFP). Out of 28 questionnaires sent out, 23 responses were returned to the CARIBE EWS Secretariat in Paris. The objectives of the survey were to confirm that the NTWCs received bulletins from the interim advisory service in a timely manner, to determine what actions were taken by the NTWCs, and to find out if the Member States activated their emergency response plans based on the available information. The survey was very useful to get an overview of the current status of the CARIBE EWS. Tsunami bulletins were received timely by most of the countries that answered the survey. On the other hand, it was identified that sea level was scarcely monitored during the event, and that some National Warning Centres (NWC) do not know how to access sea level data over the GTS or over the IOC Sea Level Observation Facility website. Most NWCs did not use any numerical models during the event. It was observed, as well, that countries placed in watch level were able to distribute warnings and even preventively evacuate some areas. It is beyond the scope of this report to conduct a detailed interpretation of the results, and the survey results have been presented so that individual Member States and the ICG can draw conclusions from this exercise and decide on future action. Although progress has been made since 2005, it should be recognized that the CARIBE EWS is not yet fully implemented and much remains to be done to bring the system to full operational status. The ICG will continue to monitor the system to ensure continuous improvement during the development phase.

Description: OpenASFA input

Description: Published

Description: Non Refereed