Earthquakes are no strangers to New Zealand, lying on the volatile “Ring of Fire,” making the early morning rocking on Tuesday, Jan.6, 2014 a dramatic but not unheard of wakeup. The magnitude 6.0 quake hit South Island in the Southern Alps, less than 100 miles from Christchurch which is still recovering from the devastating damage of a 2011 quake. Aftershocks continued for several hours after the quake, although no reports of deadly injury or destruction such as followed the earlier earthquake. Nonetheless, the Earthquake Commission reports receipt of over a dozen property damage claims around Christchurch and mid-Canterbury (like that shown above).
Residents felt the first jolts at 6:48 New Zealand time, which were felt as far away as Christchurch, 63 miles to the northwest of the epicenter on the western side of the Southern Alps near Arthur’s Pass, Methven on the opposite side as originally thought. The West Coast, Otago and Canterbury also sensed the rocking. GeoNet, the agency responsible for local earthquake monitoring, received 2,700 reports of area residents of Waikato, Southland and Christchurch that felt the earthquake rock the ground. There was discrepancy in different people’s perception of the quake which emanated from a 10 kilometer depth. Some called it short and sharp while others labeled it long and rolling. Liz McMillan, a resident of Methven, described the temblor as coming in two rolling shake waves.
GeoNet originally measured the intensity of the earthquake at 6.4 on the Richter scale but reduced it to 6.0 after further analysis. The U.S. Geological Survey took a reading of 5.6 at 10 kilometers deep. Geonet confirmed that the 6.0 rating ranks the earthquake as severe. A small foreshock just seconds before the main quake skewed the initial recordings.
The earthquake sparked a series of 30 aftershocks in the first four hours after the original shake, but did not trigger any tsunami warning, unlike quakes on other island regions around the world in recent years. The largest recorded post-quake jolt measured 4.8 magnitude at five kilometers deep near Arthur’s Pass at 5:04 p.m. John Ristau, a seismologist with GNS Science says that larger to come are within the realm of possibility. Geonet anticipates aftershocks as high as magnitude 5.0 could continue to rock the island. Damage seems to be minimal but New Zealand property owners who wish to make a property damage claim can do so online or by phone within the next three months.
Response plans are well in place in a country seasoned in up to 20,000 seismic incidents every year due to its placement on top of the border between two tectonic plates, including a few of the 6.0 or higher magnitude. In recent memory, the 2011 6.3 magnitude Christchurch earthquake claimed 185 lives earning it a reputation of one of New Zealand’s most cataclysmic tragedies in modern times. The nation’s most powerful earthquake on record is the 1855 Wellington shake which measured in at 8.2 magnitude and resulted in four fatalities, rearranging the areas’ whole geography and altering the coastline.
West Coast train lines were suspended while officials checked the tracks. Police officers were dispatched to check for road damage in Arthur’s Pass after the rocking subsided, about 18 miles east of the main earthquake zone. New Zealand authorities have received no calls for help from the area and have not issued a civil defense notice. Although some seismologists speculate that Tuesday’s earthquake could have stemmed from a previously undetected fault line, Ristau insists that this quake is comparable to others that rocked the same area over the last 100 years of seismic history in New Zealand.
by Tamara Christine Van Hooser
BBC News Asia
Image courtesy of Jocelyn Kinghorn – Flickr License