Marlborough Tsunami Evacuation Zones

Red Evacuation Zone –Shore Exclusion Zone: 0.2-1m threat level warning Orange Evacuation Zone: 1- 3m and3 –5m threat level warning –500 year return period –includes the Red Evacuation Zone Yellow Evacuation Zone: > 5m threat level warning –“worst scenario”2,500 year return period The definitions of the three tsunami warning / evacuation zones are generically described below. The Red Zone MCDEM (2008) define the Red Zone as “a shore-exclusion zone” that can be designated off limits in the event of any expected tsunami. This represents the highest risk zone and is the first place people should evacuate from in any sort of tsunami warning. People could expect ‘activation’ of this zone several times during their life.” The Red Zone is to be evacuated in response to the 0.2–1 m threat level warning. NOTE HAS TO BE TAKEN THAT THE ‘RED ZONE’ (GENERALLY UP TO 2 M ABOVE HIGH TIDE FOR EVACUATION PLANNING PURPOSES) IS CURRENTLY NOT SHOWN ON THE MAPS; THIS HAS BEEN INCORPORATED INTO THE ORANGE ZONE. The Orange Zone MCDEM (2008) define the Orange Zone as “the area evacuated in most if not all distant- and regional-source official warnings” (i.e., warnings that extend beyond the red zone, for tsunami from sources more than one hour of travel time away from the mapped location). The Orange Zone matches the 3–5m threat level warning and is to be evacuated in the event of either the 1–3m, or 3–5m threat level warning being issued (area inundated by a tsunami with a 500 year return period). The Orange Zone encompasses the Red Zone and care should be taken on the interpretation of these layers. In a situation that requires Orange Zone evacuation it is preferable to say ‘Evacuate Orange and Red Zones’, rather than ‘Evacuate the Orange Zone’ in order to avoid ambiguity. Coast Water Elevation 10.6 m at Cloudy Bay and at the Tory Channel; this is the doubled height (Powell 2013) to allow for run-up on top of MHWS (Tide levels for each Domain from LINZ). The Yellow Zone MCDEM (2008) define the Yellow Zone as covering “the maximum credible tsunami, including the highest impact events.” People should evacuate this zone in natural or informal warnings from a local source event. The Yellow Zone takes into account the worst cases from both modelling and known geological deposits and has been designed to encompass the area inundated by the tsunami with a 2,500 year return period at the 84% confidence level (Power 2013). The Yellow Zone is designed primarily for use as a self-evacuation zone in the event of a strongly felt earthquake (one that it is hard to stand up in) or a long duration earthquake (one that lasts for longer than one minute). The earthquake does not need to be both long and strong. In many cases it will be one or the other and making this clearly understood by the public is an education challenge. These earthquakes usually have a local source and if they generate a tsunami it will have a quite short arrival time for which immediate self-evacuation is necessary. The Yellow Zone should also be evacuated in an official warning for larger than the 3 – 5 m threat level or in the case of a natural or informal warning where the potential wave height is unknown. While the Yellow Zone encompasses the Orange and Red zones, care should be taken on the interpretation of these layers. In a situation that requires Yellow Zone evacuation it is preferable to say ‘Evacuate All Zones’, rather than ‘Evacuate the Yellow Zone’ in order to avoid ambiguity. Coast Water Elevation at 22.8 m at Cloudy Bay and 25.0 m at the Tory Channel; this is the doubled height (Powell 2013) to allow for run-up on top of MHWS (Tide levels for each Domain from LINZ).

This layer represents a combined coverage of the LIDAR and RAW data. Where LIDAR data is available, the RAW has been excluded. Areas where LIDAR data is truncated by the extent of the LIDAR capture, RAW data has been used e.g. Awatere and Waima Rivers.

Data and Resources

Additional Info

Field Value
Theme ["geospatial"]
Author
Maintainer mdcAGSOnline
Source http://data-marlborough.opendata.arcgis.com/datasets/75c1683dba2144a79927b1eb3718be42_16
Created 2017-11-03T01:50:43.000Z
Date modified 2019-07-08T04:33:01.000Z
Language English
Spatial {"type": "Polygon", "coordinates": [[[173.5986, -41.9722], [174.4342, -41.9722], [174.4342, -40.6545], [173.5986, -40.6545], [173.5986, -41.9722]]]}
Source Identifier http://data-marlborough.opendata.arcgis.com/datasets/75c1683dba2144a79927b1eb3718be42_16
Record created January 29, 2020, Last Updated April 10, 2020