My Job: Earth's shocks a stimulating challenge

Stephen Bannister says nearly all of New Zealand is susceptible to seismic activity. Photo / Mark Mitchell

Name: Stephen Bannister
Occupation: Earthquake seismologist
Employer: GNS Science
Age: 51
Working hours: 50-60
Pay scale: Starting range for a scientist is $60-65k
Qualification: PhD in geophysics

Describe your job

As a seismologist I work as part of the team at GNS Science to develop our understanding of New Zealand earthquakes and their effects.

Our work ranges from examining the physics behind the earthquake rupture - how the seismic energy is released - to how seismic waves from some earthquakes can trigger other earthquakes and to imaging the structure of New Zealand (which affects how seismic waves are felt strongly or weakly beneath different regions).

I work 50-60 hours a week and I'm based at the main GNS office in Avalon, near Wellington.

As part of my research I often deploy seismometer arrays in different parts of New Zealand, for several months at a time, to try to answer different science questions. Before the Christchurch earthquakes, for example, we had a focus on understanding earthquake activity on the central and northern alpine fault, so we had recorders up in the alps and on the West Coast near Hokitika.

With field work we're dependent on the farmers' goodwill to let us leave our seismometers and recorders on their farms for a few months.

Back in the office in our analysis we have strong links with colleagues in Japan and California, sharing data, ideas, experiences and results, so we all learn from each other.

What is GNS Science?

GNS Science is a Crown Research Institute (CRI) which is a Government-owned research organisation. We are not a Government department!

Before 1992 the scientists at GNS were part of the old DSIR, so there is a 150-year heritage behind our work.

GNS has 390 staff and an annual revenue of $64 million from both private and Government sources.

As well as geological sciences and mapping, GNS Science is known for its work in understanding earthquakes, volcanoes, landslides and tsunamis and in advising on measures to mitigate the physical, economic, and social impacts of these hazards. It also has expertise in identifying and managing oil and gas accumulations, geothermal energy, groundwater and mineral resources.

What is your background?

As a science graduate I spent a year working in the Australian desert and Timor Sea, exploring for oil.

I returned to New Zealand to do my PhD in seismology, recording earthquakes beneath Hawkes Bay and Mahia. On a subsequent OE, I held a fellowship in Norway, where I helped develop techniques for detecting small nuclear explosions, for the comprehensive nuclear monitoring treaty.

I returned to New Zealand in 1990 to the DSIR. In the 90s I was involved in research detecting earthquakes and icequakes in Antarctica - a wonderful experience. Now I lead the seismology research programme at GNS.

Is this a lifelong interest?

Yes, I always enjoyed science. I was encouraged to move into seismology by an inspiring lecturer at university, Dr Jim Ansell. My career pathway is reasonably typical for a scientist.

What qualifications are needed for job like yours?

A PhD is usually a requirement, although many scientists start working in a technical role, perhaps with an MSc. My own strength is ... high-resolution location of small microearthquakes, to "image" faults in the earth's crust.

Is there much work for seismologists in New Zealand?

New Zealand is an exciting natural laboratory for all earth science - one of the best places in the world for our work. The job opportunities are very limited, however - constrained by the available funding. I feel privileged to be doing the work I do.

Have other projects been put on hold while research is carried out on the Canterbury earthquakes?

Yes - we have diverted a lot of our research effort to a Christchurch focus. We've been working hard to understand the earthquakes and aftershock activity, especially the strong ground motion effects, working to provide as much information as we can which (we hope) will assist the recovery.

What areas of NZ are the most susceptible to seismic activity?

Nearly all of New Zealand is susceptible to seismic activity. The quietest seismic regions in New Zealand are Northland and Otago-Invercargill, but even those regions experience earthquakes.

Why is your job significant?

Our work helps to underpin further development of the New Zealand building code - especially for defining the expected strength of shaking beneath different regions of New Zealand.

What do you enjoy most about your work?

I find my work stimulating and challenging. I have a wonderful balance of field work, in the mountains or farms, collecting new data, as well as working on data interpretation in the office. I've been privileged to be involved in field experiments in the Transantarctic Mountains, as well as the Southern Alps.

What are your role's main challenges?

We know so little about the extreme power of nature, and are often frustrated that we can't answer many of the questions asked of us - which inspires us further. Personally, I am often challenged by the limits of my physics understanding.

Advice to those interested in a similar role?

As a college student, focus on the maths and physics basics, which will always be very useful. There is no need to specialise too early.