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See our New Zealand Earthquakes page for ongoing updates - infonews.co.nz
Staff at the Geophysics Institute, School of Geography, Environment and Earth Sciences at Victoria University are dismayed at yesterday's devastating earthquake in Christchurch.
Professor Martha Savage says that they, and most other seismologists in New Zealand had thought that the aftershocks were dying down, and a network of portable seismometers that were deployed by Victoria University and their colleagues at the University of Wisconsin after the 4 September earthquake was removed in January.
"We consider the recent magnitude 6.3 earthquake to be a late aftershock of the magnitude 7.2 earthquake on 4 September," says Professor Savage.
"Because it was shallower and closer to the city, it caused larger motion and more damage in the main city centre than the September earthquake. This new, large aftershock, will have disturbed the area, and the numbers and magnitudes of aftershocks will be larger than they were before the magnitude 6.3 aftershock. Some of the new aftershocks could be magnitude 5 or higher, and people should take normal precautions."
Continuing seismicity is being monitored by the GeoNet group at GNS Science, and their website can be found here: http://www.geonet.org.nz/
When the 7.1 magnitude earthquake struck Canterbury on 4 September, Victoria academics were called upon to provide on-the-ground advice, research-based insight and analysis as well as media commentary.
Professors Martha Savage, Euan Smith and John Townend worked with collaborators at GNS Science to analyse the earthquake. They used seismometers to get more data on aftershocks and the previously undiscovered fault line.
Professor John McClure from the School of Psychology conducted a survey of people's perceptions of risk before and after the September earthquake. He says yesterday's quake is another wakeup call to New Zealanders, and shows the importance of being prepared.
"As with all earthquakes, this earthquake shows the importance of preparation including strengthening buildings, not only having survival items such as an emergency kit. It shows that New Zealanders need to get over the idea that Wellington is the only place vulnerable to a major earthquake. As seismologists are well aware, they can happen in many parts of New Zealand.
"It is not enough to be aware of the risk, people also need to have an attitude that their actions can prevent harm and help them survive. Our recent study on perceptions of Christchurch citizens showed that Christchurch citizens who perceived the risk of an earthquake in the region as high before the September earthquake were no more prepared than those who perceived the risk as low."