GNS partners with tectonic colleagues in Japan to increase natural hazard resilience

Reducing the uncertainties of natural hazard events means governments can have more confidence to invest in the things that matter, rather than recouping sunken costs from major social and economic disruptions and rebuilds.

Constraining Hikurangi earthquake scenarios by CAT scanning the Tohoku M9 rupture area

GNS geophysicist Dan Bassett will lead a project exploring structural similarities between the Japan Trench and New Zealand’s Hikurangi Subduction Margin to investigate whether past mega tsunami generating earthquake events in Japan, particularly the 2011 M9 Tohoku-oki earthquake, could play out similarly in New Zealand.

“The Hikurangi subduction zone is New Zealand’s largest source of earthquake and tsunami hazard. However, the lack of large earthquakes in historical records means we have key uncertainties on both the magnitude and location of future earthquakes, as well as the size and impact of resulting tsunami,” Dr Bassett said.

“By partnering with Japan, we can tap into a rich data source compiled from their world-leading earthquake monitoring networks, extensive geophysical datasets and recent history of giant earthquakes to investigate whether there are specific lessons from Tohoku that we can use to refine, calibrate or test scenarios of earthquake and tsunami generation along New Zealand’s Hikurangi margin.”

The project will CAT-scan the subduction zone that produced the Tohoku earthquake using a pioneering technique to build a high-resolution 3D model of the structure and elasticity of the Tohoku subduction fault. The model will be studied to assess:

• whether the distribution and elastic properties of crustal rocks played a role in producing the 60-metre fault slip that generated a tsunami wave up-to 40-metre high, impacting more than 2,000 kms of coastline, and
• whether the southern Hikurangi Subduction Zone exhibits similar or different properties to the Tohoku subduction fault, which may impact the likelihood of a similar earthquake rupture occurring in New Zealand.

Building a Japan Aotearoa network for catastrophic eruption planning

GNS risk scientists Christina Magill and Josh Hayes will co-lead a project to develop new ways to model the impacts of ashfall from large explosive volcanic eruptions. Their work aims to support mitigation measures, limit damage, restore services and minimise socio-economic disruptions of future events. 

“Ashfall can cause substantial impacts in both urban and rural areas, affecting critical lifelines, transport, health, farming, manufacturing, and business. Our research will focus on the impacts that must be quickly mitigated to enable effective emergency response and return functionality to wider society,” Dr Magill said.

“Japan experiences frequent ash falls from volcanoes such as Sakurajima in Kagoshima. By partnering with Japan, we can learn much from their experiences with volcanic eruptions.

“Researchers and stakeholders from both countries will share expertise and experiences and form a volcano alliance, enabling each country to support the other in preparing for future widespread ashfall events.

“Having this alliance in place means each partner is well-prepared to quickly support the other should the time come.”

• The project will:
  leverage ashfall hazard simulations to develop plausible scenarios that consider ash deposition over a prolonged time and remobilisation due to wind and rain,
• develop new volcano impact modelling methodologies, and simulate response and recovery strategies,
• work with emergency managers and lifeline providers to prioritise and determine how quickly services such as electricity and transport need to be restored to support optimal response,
• explore optimisation strategies for ash clean-up and infrastructure system restoration that would minimise socio-economic disruptions.

The research teams will each receive $300,000 from the Government’s Catalyst Fund.  Japanese research teams will receive equivalent funding from our Japanese partner – the Japan Science and Technology Agency.

GNS Science will work with the Japan Agency for Marine Earth Science and Technology (JAMSTEC) to undertake the seismic study of the Hikurangi subduction zone.

GNS Science will work Japan’s National Research Institute for Earth Science and Disaster Resilience (NIED) and the University of Canterbury on tolerable levels of ashfall following volcanic events.