THREAT: An orange zone has been identified around Te Waihora/Lake Ellesmere and Selwyn’s coastline, based on tsunami risk.
About 500 Selwyn households close to the ocean or Te Waihora/Lake Ellesmere have received a letter with advice on what to do if there is a tsunami threat.
These properties are located within an ‘orange zone’ which may need to be evacuated in the event of a tsunami warning.
Selwyn civil defence controller Douglas Marshall said the boundaries for the orange zone had been identified based on scientific advice from Environment Canterbury on the maximum credible event that could impact Selwyn.
None of Selwyn’s main townships are considered to be at risk from tsunamis with the closest, Leeston and Southbridge, both outside the orange zone. Smaller settlements inside the orange zone include Rakaia Huts, Taumutu, Upper Selwyn Huts, Lower Selwyn Huts and Greenpark Huts.
“If a tsunami warning was issued, people inside the orange zone may need to evacuate this area,” Mr Marshall said.
“We have written to these property owners to advise them to sign up for our emergency text and email alert system Selwyn Gets Ready and to provide advice on what to do in a tsunami threat.”
Three types of tsunamis could affect Selwyn.
Distant tsunamis are generated from a significant distance, such as from across the Pacific in Chile. There will be more than three hours warning time for New Zealand for these tsunamis, and more likely longer.
Regional tsunamis are generated between one and three hours travel time away from their destination. An eruption from an underwater volcano in the Kermadec Trench to the north of New Zealand could generate a regional tsunami.
Local tsunamis are generated very close to New Zealand. With this type of tsunami there is no time to issue an official warning and people will need to respond immediately.
Three evacuation centre locations have been identified at Lincoln Event Centre, Leeston Library and Southbridge Hall where people can go after evacuating.
If there is time to do so, volunteer community response teams will door-knock in affected townships and district council and emergency services will also warn residents using emergency vehicle sirens.
“In a close to shore tsunami there will not be time to issue a warning,” Mr Marshall said.
“If you feel a long or strong earthquake or see a sudden rise or fall in sea level or hear loud or unusual noises from the sea then people should move inland or go to higher ground as soon as possible.”
The orange zone extends between 1km and 7km from the coast depending on local factors. Mr Marshall said it was likely to be reviewed and reduced next year as the initial zoning had been very cautious.
For more information on tsunami risk and warnings in Selwyn, visit www.selwyn.govt.nz/tsunami