In January, a 7.0 quake hit Haiti, and 230,000 people died. Today, a 7.0 quake hit New Zealand, and early indications are that it caused relatively few serious casualties. Why the difference? The main reasons don't have to do so much with the earthquakes themselves. "This was very similar to the earthquake that struck Haiti," said Paul Caruso, a geophysicist at the U.S. Geological Survey's National Earthquake Information Center in Golden, Colo. "The main difference is that New Zealand has a lot of experience with earthquakes, and they have good construction codes to make sure that their buildings withstand a strong earthquake." In contrast, Haiti is one of the poorest nations in the world, was far less prepared to withstand a seismic shock. Building standards were virtually non-existent. The infrastructure simply couldn't withstand a quake, in a place that's more used to weathering hurricanes than seismic shocks. January's quake was the biggest to hit the island of Hispaniola since an 8.1 event in 1946. Looking at it in purely geological terms, you could see lots of eerie similarities between the quakes in Haiti and New Zealand: Both involved strike-slip faults, meaning most of the shaking was side to side. Both were shallow, which is usually a bad sign for earthquake damage (8.1 miles for Haiti, 7.5 miles for New Zealand). Both were close to major population centers (25 miles from Port-au-Prince in Haiti, 35 miles from Christchurch in New Zealand). Both events sparked some seismological intrigue: Scientists recently determined that the surprisingly strong Haiti quake occurred along a fault line that was previously undetected. The New Zealand quake occurred close to two well-known fault lines, the Alpine and the Hope faults. Seismologists have been particularly concerned about the Alpine Fault, which is known to have produced several quakes in the range of magnitude 8 over the past 900 years. The New Zealand government's GNS Science agency recently said the Alpine Fault had a "high probability" of rupturing within 40 years. "The rupture will produce one of the biggest earthquakes since European settlement of New Zealand, and it will have a major impact on the lives of many people," the agency said. However, this doesn't appear to be New Zealand's Big One. Caruso of the USGS said seismologists were still trying to reconstruct the exact cause of today's quake. "We think that this is a very complex event," he told me. "We think that the main shock may have consisted actually of three earthquakes." Looking beyond the infrastructure, the other main reason why the casualties were so great in Haiti, and so few in New Zealand, had to do with the time of day. Haiti's 7.0 event came at 4:53 p.m., when lots of people were out in the streets of the city. New Zealand's came at 4:35 a.m., when most folks were home in bed. If you have to weather a 7.0 shock, that's not a bad place to be, Caruso told me. "One of the worst things you can do in an earthquake is run outside, because stuff is falling down," he said. "If people stay in their houses, they're a lot safer." It's way too early to say precisely how serious the quake's impact is: Reports of damage and injuries from the field don't typically flow in as fast as Twitter updates. (To keep up with the stream, search for the hashtag #eqnz. You can also check the minute-by-minute reports from the New Zealand Herald.) Some New Zealanders are being evacuated, and others are encountering outages in electrical power as well as water and sewer service. The quake caused serious damage to buildings and transportation infrastructure, and it's clear that significant repair and rebuilding will be required in the months ahead. But even at this early stage, it's also clear that New Zealand is no Haiti. Thank goodness. More about earthquakes:
- Survivor: 'We got the animals and ran'
- Photoblog: First pics from quake scene
- Gallery: A dozen killer earthquakes
- Interactive: What causes earthquakes?
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