NOTE: The contents of this handbook are patterned after previous LANTEX and CARIBE WAVE Exercises (e.g., Commission Océanographique Intergouvernementale. Exercise Caribe Wave 11. A Caribbean Tsunami Warning Exercise, 23 March 2011, IOC Technical Series No. 93. Paris, UNESCO, 2011 (English/ French/ Spanish), Intergovernmental Oceanographic Commission Exercise Caribe Wave/Lantex 13, A Caribbean Tsunami Warning Exercise, 20 March 2013, Volume 1: Participant Handbook, IOC Technical Series No. 101, Paris, UNESCO, 2012 and Intergovernmental Oceanographic commission. 2013. Exercise Caribe Wave/Lantex 14. A Caribbean and Northwestern Atlantic Tsunami Warning Exercise, 26 Marc 2014. Volume 1: Participant Handbook. IOC Technical Series, 109 vol. 1. Paris: UNESCO. (English and Spanish)). These CARIBE WAVE handbooks followed the Pacific Wave 08 manual published by the Intergovernmental Oceanographic Commission (Exercise Pacific Wave 08, A Pacific-wide Tsunami Warning and Communication Exercise, 28-30 October 2008, IOC Technical Series No. 82, Paris, UNESCO, 2008). The UNESCO How to Plan, Conduct and Evaluate Tsunami Wave Exercises. IOC Manuals and Guides No. 58 rev., Paris: UNESCO, 2013 (English, Spanish) is another important reference.
Appendix E: Sample Press Release for Local Media....................116
NOAA and the U.S. National Tsunami Hazard Mitigation Program (NTHMP) are providing the framework for the LANTEX16 tsunami exercise, which is being conducted to assist tsunami preparedness efforts throughout the northern Atlantic region. Recent earthquakes and their associated tsunamis, such as those in Samoa-2009, Haiti-2010, Chile-2010, Japan-2011, and Chile-2015, attest to the importance of proper planning for tsunami response. Similar recent exercises in the Pacific and Caribbean Basins have proven effective in strengthening preparedness levels of emergency management organizations.
This exercise will provide simulated tsunami alert messages from the NOAA/NWS National Tsunami Warning Center (NTWC) for the eastern coasts of Canada and the United States. The alert is based on a magnitude 6.8 earthquake located approximately 130 miles south of Halifax, Nova Scotia and 400 miles east of Boston, Massachusetts at 42.7ºN, 63.2ºW (Figure 1) which triggers a sub-sea landslide. The sub-sea landslide in turn generates a tsunami.
Figure 1. LANTEX16 source location.
Tsunami warning services for the United States and Canada are provided by the NTWC in Palmer, Alaska, while the Pacific Tsunami Warning Center (PTWC) in Pearl Harbor, Hawaii provides services for locations within the Caribbean region. These Centers issue messages to the region approximately two to six minutes after an earthquake’s occurrence. The NTWC products include warnings, advisories, watches, and information statements. Primary recipients of Tsunami Warning Center messages include national tsunami warning focal points, Weather Forecast Offices (WFO), state/territory emergency operation centers, national Coast Guards, and military contacts. These agencies disseminate the messages to people potentially impacted by a tsunami.
A short description of landslide generated tsunamis is given below and is based on information at the following web sites:
http://projects.noc.ac.uk/landslide-tsunami/project-information, http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.16.9503&rep=rep1&type=pdf, and
Submarine landslides are known to generate tsunamis by displacing a large amount of sea water in a short time frame. The 1929 Grand Banks earthquake and tsunami is an excellent example. This magnitude 7.3 earthquake located south of Newfoundland triggered a massive sub-sea landslide estimated at 100 cubic kilometers in size which generated a tsunami reaching 13m runup (maximum vertical elevation reached onshore) along the Newfoundland coast. Twenty-eight people were killed by this tsunamis.
Landslide tsunamis possibly constitute the biggest tsunami hazard to the U.S. and Canadian Atlantic coasts. In addition to the 1929 tsunami mentioned previously, other landslides have been identified off the U.S. east coast. Only a small number have been dated and they are generally older than 10,000 years. Analysis of landslide statistics along the fluvial and glacial portions of the margin indicate that most of the landslides are translational, were probably initiated by seismic acceleration, and failed as aggregate slope failures.
Submarine landslides can be much larger (two orders of magnitude) than those on land. For example, the Storegga Slide off Norway affected an area larger than Scotland, and the amount of sediment it mobilized is enough to cover Scotland to a depth of 80m. The largest of all submarine landslides occur on nearly flat (<2º) continental slopes. Since the volume of mobilized material in a landslide is a critical parameter for tsunami generation, these enormous landslides often generate tsunamis.
Figure 2 shows the evolution of a submarine landslide on its way from the continental slope to the abyssal plain On its downslope journey, the slide mass itself remains intact, breaks up into distinct blocks or deforms internally. A cloud of suspended particles forms and divides into a debris flow at the bottom and a turbidity current on top. The debris flow travels faster on steeper portions of the slope but stops eventually due to frictional forces, while the turbidity current can travel very long distances.