Department of Geoscience, University of Calgary
CMC Theme Lead, Secure Carbon Storage
When: 4 p.m., Nov. 2, 2012
Where: ES162, University of Calgary
Don Lawton, University of Calgary Professor of Geophysics and CMC’s Secure Carbon Storage theme lead, will be speaking about seismic work he undertook in Christchurch, New Zealand after the devastating 2010 earthquake. After the quake, Lawton was invited by the New Zealand government to help assess the risk of further earthquakes using seismic equipment.
Lawton’s talk is one of 20 he is undertaking as part of the 2013 Canadian Society of Exploration Geophysicists Distinguished Lecture tour. He will be travelling to 20 cities across Canada and the US to discuss his work in New Zealand.
On September 4, 2010, an earthquake struck the Christchurch region in New Zealand. The Mw 7.1 quake was centered about 40 km west of the city of Christchurch and caused significant damage but no loss of life. A key manifestation of the earthquake was a fault (Greendale Fault) that ruptured to the ground surface with a maximum dextral displacement of 5.1 m and a vertical displacement of 1.5 m, upthrown to the south. On February 22, 2011, a Mw 6.2 aftershock struck with a shallow hypocenter very close to Christchurch. This earthquake resulted in the loss of 182 lives and devastating damage (|$23B) to the city infrastructure. Since September 2010, the region has experienced over 10,500 aftershocks, with 42 of these being greater than 5M.
Seismic data recorded
Approximately 45 line-km of high-fold reflection seismic data were recorded in and around Christchurch following the February 22, 2011 aftershock. The goal of the seismic program was to map previously unknown shallow faults in and around the city for hazard assessment and to assist in the post-earthquake recovery effort. Reflection seismic data were collected along six 2D lines, two of which were within the Christchurch metropolitan area and four were in rural areas west of the city. Recording conditions were challenging within the city, but good quality images were obtained along all of the seismic lines, with events interpretable to a depth of approximately 1.5 km. Numerous faults were imaged along the lines and these were interpreted in two groups – older faults that showed clear offsets in deep (> 1 km) reflections and younger faults that showed displacement in shallow reflections. Some faults in the latter group were interpreted to be directly associated with hypocentres of the earthquake and aftershocks.