Jefford on Monday: Wine in the ring of fire

Earthquakes are a part of life for most of us - the UK, for example, gets several hundred a year.

Size, though, is all.

Half a million earthquakes affect our planet every year, but humans only sense one in five of them. The world can expect 18 major quakes (magnitude 7-7.9 on the Richter scale) a year, plus one great quake (magnitude 8 or more).

Europe isn’t immune. The Lisbon earthquake of November 1755 (in fact it happened 200 km out in the Atlantic) was, at 8.7, one of the greatest in recorded history, and the Messina catastrophe of December 1908 was one of three major quakes to affect Italy since the late seventeenth century.

It’s in what’s known as the Pacific Ring of Fire, though, that the risk rises steeply: this zone experiences 91 per cent of all the world’s earthquakes, and 81 per cent of the largest.

As the name suggests, jostling tectonic plates in and around the Pacific are to blame.

If, as an aspiring winemaker, you feel that earthquakes are simply one risk too far, then the zones to avoid are Chile (the highest risk of all, with three of the nine worst earthquakes in recorded history — last year’s Maule quake caused USD $250 million’s worth of damage); the Western seaboard of the USA, and especially Southern California; Japan … and New Zealand, where two significant earthquakes in the last six months in and around Christchurch on the South Island have struck to tragic effect.

The country sits on the boundary of the Pacific and Australia plates with an unusually large movement zone between them, hence the fact that the country has suffered 17 major and one great quake since 1843 alone.

The most earthquake-prone parts of New Zealand are, in fact, wine regions: Hawkes Bay, Wairarapa (Martinborough), Marlborough and Canterbury have all experienced one or more major quake since 1843, and they won’t be the last.

Indeed Kiwi geologists (like the great Harold Wellman) have made a speciality of reading recent earth movements in the landscape.

The ridges, hills, mountains and rivers in key New Zealand wine zones are all unusually mobile, displaced by diagonal fault lines which move almost 50 mm a year from northeast to southwest.

It’s some of the greatest winemaking terroir in the Southern Hemisphere; it’s beautiful country; but it will always be dangerous.

Written by Andrew Jefford