10 Sep 2016

Raising the alarm when quakes strike

From Mediawatch, 9:08 am on 11 September 2016

Reports of a post-quake tsunami on the way caused near-panic around Gisborne 10 years ago, and prompted a promise it wouldn't happen again. Did the authorities and the media get it right when a closer quake raised the same fears last week?​

Civil Defence released this map showing Tsunami threat levels.

Civil Defence released this map showing Tsunami threat levels. Photo: MCDEM

Many people around the country woke up on September 2 to news of a big quake off the East Coast of the North Island.

But those in the region were shaken awake by it at 4:38 am and some near the coast were alerted to evacuate soon after the 7.1 quake.

Major broadcasters have a memo of understanding with the Ministry of Civil Defence and Emergency Management (MCDEM) for broadcasting emergency information. RNZ and TVNZ are designated as “lifeline utilities” and are obliged to broadcast official information no matter where the emergency is.

But in the past, issuing and the crucial information hasn’t always gone smoothly.

In 2006, there was near panic in and around Gisborne when BBC World TV said a tsunami would strike within an hour after a quake near Tonga. That  It turned out to be a false alarm, but the Civil Defence system hadn’t taken into account the possibility of international media reporting a threat before the local ones.

Promises were made about getting it right next time, and a red emergency hotline phone was installed in RNZ’s newsroom.

When a big quake struck near Samoa last 2009 – that red phone never rang – though it did work after Chile in 2010, which prompted a full rolling news special on a Sunday.

What happened this time round on 2 September?

Shortly after 5:15 am, RNZ National and RNZ.co.nz reported that people in coastal areas near East Cape had been advised by the local civil defence to evacuate. But at 5:30 Newstalk ZB said it didn’t have any advice, and it reported CNN as saying a tsunami was possible.  

TVNZ put information on its One New Now website from 5:15 am onwards, but nothing was broadcast on TV One until its Breakfast show got going at 6 am.  

This week Mediawatch asked MCDEM about the emergency response on the day - and if the media had done its job.

We received this statement from the director of Civil Defence and Emergency Management, Sarah-Stuart Black.

  • Friday’s tsunami was a local source event, i.e. it resulted from an earthquake that occurred within 500km of New Zealand. In a local source tsunami, the travel time of the first waves to the nearest coasts is potentially only a few minutes.  There may therefore be little time to issue official warnings and it is possible that an official alert will not be issued before the first waves actually arrive at the areas nearest to the earthquake.

  • This magnitude 7.1 earthquake did not trigger the threshold for an immediate decision to issue a tsunami warning (the threshold is a magnitude 7.5 earthquake at less than 100km deep). 

  • When the earthquake does not meet the threshold, it is agreed practice for the Ministry to receive advice from tsunami experts (GNS Science and the Tsunami Experts Panel) on the likely threat, prior to issuing a potential threat advisory or warning. It generally takes up to 30 minutes to produce a tsunami threat assessment. GNS Science have subsequently noted that the earthquake may have been two earthquakes, and its complexity made it hard to estimate how deep the earthquake was and whether there was any tsunami threat.

  • We may proactively issue an advisory prior to receiving that advice, which we did in this case. This decision is balanced against issuing premature notifications which could be seen as ‘crying wolf’, leading to a lack of trust in our communications.
  • MCDEM’s public education emphasises that following a local source tsunami there may not be time for the public to receive an ‘official’ notification. Our advice is that people should heed the natural warning signs of tsunami and take appropriate action (i.e. do not wait for official warnings). If the earthquake makes it hard to stand up, or is a rolling earthquake that lasts a minute or more, or where changes in the sea are observed (rapidly going out, rapidly coming in or making noise) this should be taken as an immediate warning for coastal populations to take action to move inland or uphill to keep themselves and their families safe.
  • We are pleased that local communities around Gisborne, East Cape and Tolaga Bay followed this advice and self-evacuated on Friday morning to pre-planned locations, once the earthquake was felt.  This is exactly the right action to take and those communities deserve to be applauded. Local Civil Defence Emergency Management (CDEM) officials worked effectively and efficiently in responding to this event, in line with their pre-prepared plans.
  • In regards to the performance of media – we believe the media performed well in acting promptly to get the word out through a multitude of channels and in an informative and timely way.  The media plays an important role in public safety during events such as tsunami, and we are grateful to media organisations for helping to alert the public to the threat of an approaching tsunami.
  • We note that some media called the Pacific Tsunami Warning Centre (PTWC) for more information, who subsequently informed there was no threat while there was actually a warning in place for New Zealand. The PTWC is not the correct source to go to for information about specific risks to New Zealand. It is important that New Zealanders have a single authoritative source to go to, and during a tsunami threat this is MCDEM and local Civil Defence Emergency Management.
  • In regards to criticism of the response time as reported by media, some outlets focused on the 5.58am time at which the warning was issued. We note that a ‘Potential threat’ advisory had been issued earlier (5.36am). As noted earlier, we advise coastal communities to take action immediately, rather than wait for an official warning. This is exactly what affected communities did, which shows that our advice – and the hard work of local Civil Defence Emergency Management Groups* – has been effective in helping to protect the public.
  • The Ministry has a project currently underway looking at our current processes for national warnings, including looking at the timeliness of alerts. Any changes to our processes will be considered as part of this project.

Timeline - supplied by MCDEM

  1. At 4.41am on Friday, we received from GNS Science initial notification of a magnitude 6.3 earthquake, 34km deep off the East Cape of the North Island.  At this magnitude, no action is required under the tsunami response indicators the Ministry has agreed with GNS Science. The Ministry’s scientific advice and initial assessment of the threat to New Zealand from an earthquake comes from GNS Science and the Tsunami Experts Panel.
  2. We were made aware at 4.53am that the earthquake had been upgraded by GNS Science to a magnitude 7.1 and depth 55km. To be proactive in the meantime, we issued an ‘Earthquake Advisory’ at 5:10am.  The earthquake advisory confirms the size and depth of the earthquake and provides public safety information.
  3. Whilst GNS Science were assessing the tsunami threat, we took the decision to proactively issue a ‘Potential Tsunami Threat Advisory’ at 5:36 am.  The potential tsunami threat advisory confirms the current threat is unknown, the impact of the earthquake is being assessed to determine the potential tsunami threat to New Zealand or the characteristics of the earthquake are such that there is a possibility a tsunami has been generated. The advisory also provides public safety information.
  4. A ‘Tsunami Warning’ was issued at 5:58am after the Experts Panel confirmed the tsunami threat to MCDEM. We continued to liaise with GNS Science and the Tsunami Expert Panel to reassess the threat. Subsequent updates were issued until the threat was cancelled at 8:30am.