Warn­ing over threat from gi­ant megath­rust quake

The Hastings Mail - - FRONT PAGE - STAFF RE­PORTER

An 8.4 mag­ni­tude quake off the East Coast of New Zealand could re­lease 2000 times more en­ergy than the 2011 Christchurch earth­quake, ex­perts say.

It could cause a ‘‘megath­rust’’ earth­quake, and the dan­gers it poses were be­ing dis­cussed at a sum­mit in Napier last week – with lo­cal coun­cils, iwi and civil de­fence in­volved.

The po­ten­tial risk comes from the Hiku­rangi sub­duc­tion zone, a mas­sive fault line run­ning from Marl­bor­ough and right past the East Coast where the Pa­cific and Aus­tralian tec­tonic plates col­lide.

It is po­ten­tially the largest source of earth­quake and tsunami haz­ards in New Zealand, but sci­en­tists say there is still much to learn about it.

GNS Sci­en­tist Dr Laura Wal­lace told TVNZ ‘‘it’s a mas­sive plate bound­ary fault and sub­duc­tion zones. Be­cause they’re so large [they] have the po­ten­tial to pro­duce the world’s largest earth­quake and tsunamis’’.

Mar­cus Hayes-Jones from Napier Civil De­fence said he ‘‘can’t em­pha­sise how se­ri­ous’’ New Zealand must take this ‘‘gen­uine risk’’.

In 2015, sci­en­tists fi­nally found proof that cen­tral New Zealand could be tick­ing down to a highly dam­ag­ing ‘‘megath­rust’’ earth­quake.

Pre­vi­ous re­search has shown the Hiku­rangi-south­ern Ker­madec sub­duc­tion zone seg­ment had the char­ac­ter­is­tics of the lo­ca­tions of pre­vi­ous gi­ant earth­quakes.

In a gi­ant earth­quake a very large part of a fault slips.

In the Box­ing Day 2004 quake off Su­ma­tra, which caused a tsunami that killed more than 200,000 peo­ple, about 1300 kilo­me­tres of the sub­duc­tion zone fault slipped.

The Hiku­rangi sub­duc­tion zone is part of a larger sub­duc­tion zone called the Hiku­rangiKer­madec-Tonga sub­duc­tion zone which stretchs all the way to Tonga.

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