This weekend I attended the New Zealand Society for Earthquake Engineering conference, entitled From Inangahua to Kaikoura and Beyond. The NZSEE publishes conference papers (with a small delay) at its website, so it’d be unnecessary as well as presumptuous to attempt to summarise individual presentations. What I do want to do, briefly, is set down my impression of the two conflicting schools of thought at the conference about the …and Beyond part of the theme. Why? Because the way in which this apparent dichotomy gets resolved might make a big difference for heritage conservation.
Blinded by Science
One camp says that engineers have started to believe their own hype. Dazzled by the potential of Big Data, and the promise of sophisticated software models, engineers have started to believe that they can not just model events and natural phenomena but predict them. They’ve been quoting coefficients to two decimal places as though that were meaningful, and producing special studies to permit themselves to avoid meeting minimum performance standards.
Instead of getting more and more specialised, this argument says, and instead of running ahead of the capabilities of the profession and the reality of commercial practice by dreaming up increasingly complex methods, let’s adopt a basic risk model that covers the whole country more or less equally. And let’s not focus on a minimum standard of safety, but on designing structures that might still be useful for something once the dust settles.
In the Weeds
It’s a technical conference. Many of the presenters were there to talk about their research into specific avenues of knowledge: how earthquake waves propagate; how concrete floors deform; the probable intensity of shaking at a given time and place. Instead of generalising across the country and working from first principles, their goal is to discriminate between individual cases and to know how to treat ’em. Research, modelling, and better, more ubiquitous instrumentation holds the key to tailoring solutions to specific problems.
Heritage in the hinterlands
I’m not qualified to judge; but I do have an opinion. For what it’s worth (you decide), I’m leaning towards the idea that—for the moment—we need to accept a different level of risk in different places. I got interested in working with heritage and engineering in part because I was thinking about the fate of small-town New Zealand in a post-Christchurch era. I don’t want to see the embodied history in those places obliterated. To my way of thinking, it’s clear that if we adopt the school of thought that everywhere in the country should be treated more or less the same, we’re going to have to demolish a lot of old buildings. They just don’t make enough money to pay for their own repair.
At Pompeii, the state-of-the-art archaeological practice is to leave everything in the ground. There’s masses of unexcavated material. But too much has already been excavated—we can’t conserve it all— and it’s getting ruined by exposure. Besides, the science is advancing so much that it’s smart to leave plenty untouched. Analysis methods that haven’t been developed yet might be able to tell us marvellous things about Roman life—if we don’t get too eager and stuff up all the raw data.
What’s the analogy? The pace of innovation in earthquake engineering is immense. In my opinion, it might be smarter to use the science we have to tell us where shaking is likely to be less intense, and, for now, do little or nothing to historic buildings in those places. Yes, it would be riskier living in an old building in Paeroa than in Ponsonby. And it’s all very well for me to say, since I don’t live in an old building and I don’t live in a small town. But the alternative is that we bulldoze our history too hastily. Let’s be smart about fixing the worst stuff, and be equally smart about leaving the less risky stuff for a later, wiser time.
To the kind and generous real engineers who spent their time talking to a wannabe engineer! And also to the speakers and organisers of the conference. It was excellent.