Civil protection authorities need guidance in order to establish comprehensive emergency plans for tsunami-prone communities.
Tsunami hazard scenarios are built up by specifying the various characteristics of one or more tsunamigenic sources (possibility of earthquakes and sub-marine landslides, historical earthquakes and sub-marine landslides). A tsunami evacuation plan is a plan that will be invoked if a tsunami alarm has been triggered. Figure 2: Generalized scheme of evacuation planning (Nagao 2005)At first sight, one will choose those higher located areas as safe locations (shelters) that will not get flooded according to predictions of the tsunami hazard scenario.
The decision to declare a scenario instance as a valid instance (suitable to be taken up within a tsunami evacuation plan) depends on whether all affected persons will have arrived at “their” safe location within the given time span. On basis of the matrix of Table 3 and on basis of the to-be-expected tsunami wave height, a decision maker has sufficient means to create an inventory of buildings suitable to be included in the list of additionally to be considered vertical shelters. The inventory of vertical shelter buildings provides a good basis for an optimization of evacuation plans.
In a first category, one can include all those objects that can easily be mobilized and carried away by tsunami currents, to avoid huge amounts of debris that can significantly increase the destructive power of atsunami. As defined in the SCHEMA project, damage maps could also be enhanced by a quantitative assessment of the wave velocities (at each location) as an additional outcome of the tsunami hazard scenario; alternatively, if possible, a qualitative assessment could be made for each location considering its exposure to the waves. A valid instance of a tsunami evacuation plan is a scenario that allows evacuating all affected people toward safe locations in time. Prior to the selection of vertical shelters, an evacuation plan may be a valid instance; in that case the selection of additional vertical shelters may improve the performance of an evacuation plan. Mid-term maintenance of an existing evacuation plan consists in constantly checking the availability as well as the accessibility (including the escape routes) of horizontal and vertical shelters. Long-term maintenance consists of counterchecking an existing plan against its acceptance within the population in addition to the postulation of changes within the basic parameters resulting from the tsunami hazard scenario. Evacuation plan generation should consider, on top of local topologies, the outcome of tsunami hazard analysis. The proposed damage matrix serves as input for decision makers who, on basis of the expected inundation depth, select those buildings that could withstand a to-be-expected tsunami and which could serve as additional vertical shelter buildings. Emergencies come in many shapes and sizes, but, here on the coast, the primary threat to residents and visitors are tsunamis, earthquakes, and severe winter storms. Each community has worked with the County OES and the state to develop evacuation plans based on their topography, inundation zones and populations along the coast.
The California Governor’s Office of Emergency Services and the California Geological Survey announced the revised plans earlier this week as part of Tsunami Preparedness Week. Prior to the new playbooks, the tsunami plan was a single, one-size-fits-all response for communities--from those with steep cliffs and no population to those with docked boats, homes or businesses along the water.


Last year, OES mailed tsunami flood surge maps and evacuation routes to the homes and businesses in the tsunami flood surge zone of each of the ten communities. San Diego’s 70 miles of coastline could experience a tsunami caused by a faraway earthquake or one close to shore. If a local quake or undersea landslide produced the tsunami, shaking from the quake itself or rapidly receding water might be the only warning signs. The tsunami preparedness strategy will later include maritime response playbooks with harbor planning and guidance for reinforcing harbor structures. In particular, the safe evacuation of all potentially affected persons prior to the arrival of the first devastating tsunami wave should be the primary goal in case of a tsunami alert. Through computer simulations, the oceanic tsunami wave propagation (arrival time of first tsunami wave on land, time intervals between the various waves) and its local effects on land (extent of inundation, wave heights) can be calculated. Hence, such a plan will affect preparedness measures among which the evacuation of the population is the most important. A mathematically-based, time-cost algorithm does the necessary simulation; as positive outcome a complete evacuation of the affected population is guaranteed, while in the negative case, the simulation will show that some parts of the affected population may still be affected by tsunami waves. In the contrary case, those parameters should be changed in such a way that an improvement (with respect to full evacuation) can be measured within a simulation repetition. Among the most important ones in terms of evacuation measures are lifelines, such as roads usable as escape routes, and buildings, usable as additional vertical shelters.
The latter, though not being of primary importance for the tsunami evacuation planning, could be of use during a first range of response actions by identifying those buildings that could have hosted evacuees. These functions have been developed empirically from a database compiled in the southwest area of Banda Aceh (Indonesia) being hit by the 2004 Indian Ocean tsunami (see Figure 3). Though quantitative assessment of tsunami damage to these elements could become quite complex, a qualitative assessment could at least be of importance with respect to the feasibility of an evacuation plan. One characteristic here is that – after a tsunami – debris may block access to (and exit from) that building. Courtesy of CRTS (Morocco) and ACRI-ST (France)The final list of potential vertical shelter buildings provides suitable options to use for further improving a tsunami evacuation plan.
Safe locations are by definition situated outside the inundated area; however, with the availability of additional vertical shelters, it is advisable for inhabited regions to augment the number of nearby shelters thus reducing the time for evacuation and making evacuation less complex.
On the other hand, if an evacuation plan does not demonstrate that all affected persons could evacuate in time, and that all other parametric options like choosing appropriate escape routes have been considered, the selection and inclusion of additional vertical shelters becomes mandatory. On the basis of additional shelters, the evacuation simulation procedure should be launched again and eventually produce satisfying results.
Among the many preparedness tasks for authorities, there is in particular the proper training of residents and proper education of specific parts of the population (children, elderly, handicapped, etc.), on evacuation measures on top of well-elaborated instruction and divulgation of the existing evacuation plan.


The latter, in particular, could easily make an evacuation plan obsolete which, in turn, requires a restart of the whole evacuation plan generation procedure. This basically means to overlay the expected maximum inundation zone with the topology and to set a basic time constraint for a full evacuation to take place.
Within various optimization steps, each simulation procedure can be fine-tuned by adding suitable vertical shelters to the map of shelters within the evacuation map. Naval installations could refer to new tsunami response “playbooks” that include tailored, phased evacuation and mitigation plans for each area. In San Diego County, emergency managers had one of two choices: clear the beaches only or evacuate the whole region’s tsunami evacuation zone, with its approximately 33,000 homes and businesses. If a distant quake caused a tsunami, the federal National Tsunami Warning Center in Alaska would warn local officials of the approaching surge.
Evacuation is usually done on basis of well developed evacuation plans that operate on a given topography.
Hence, as basic input to the generation of tsunami evacuation plans, the expected flooded areas and the expected maximum wave height in these areas will be exploited in order to define the maximum number of affected persons and the time constraints to evacuate these persons onto safe areas. The flow of debris brought forward and left behind by tsunami waves is also of importance as evacuation may be tampered and rescue operations may be hindered dramatically.
Such areas, for example, pose the risk that many other objects are hit by tsunami waves thus creating additional problems. Hence a valid instance of an evacuation plan is created step by step, including more and more vertical shelter buildings into the plan [Scheer et al., 2011]. New tsunami damage functions developed in the framework of SCHEMA project: application to Euro-Mediterranean coasts, Nat. She is an expert in numerical modelling of seismotectonic processes and works on natural hazard and vulnerability assessment, especially focusing on earthquakes and tsunamis. In particular and prior to their inclusion within an evacuation plan, vertical shelters (buildings, platforms) have to successfully pass damage scenarios that check their stability during a tsunami. Analyse spatiale des dommages au bati de Banda Aceh (Sumatra, Indonesie): contribution a la connaissance du phenomene et a l’elaboration de scenarios de risque tsunami.



How to prepare for a tsunami video
What is an emergency preparedness and response plan


Comments

  1. 07.06.2015 at 13:28:52


    The potential to can your own outdoor odyssey will asthma.

    Author: NIGHTWOLF
  2. 07.06.2015 at 14:20:53


    Recognize how dependent you stranded someplace, I would.

    Author: LINKINPARK