TELESEISMIC AND NEAR-FIELD ANALYSIS OF THE NAHANNI EARTHQUAKES IN THE NORTHWEST TERRITORIES, CANADA
The analysis of the Nahanni earthquakes of October 5, 1985 (Ms 6.6), and December 23, 1985 (Ms 6.9), will have important implications for the assessment of seismic hazards in intraplate environments. To maximize the information available to seismic engineers, broadband data recorded teleseismically...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.133.4909 http://bssa.geoscienceworld.org/cgi/reprint/78/5/1627.pdf |
| Summary: | The analysis of the Nahanni earthquakes of October 5, 1985 (Ms 6.6), and December 23, 1985 (Ms 6.9), will have important implications for the assessment of seismic hazards in intraplate environments. To maximize the information available to seismic engineers, broadband data recorded teleseismically are analyzed jointly with strong-motion data recorded in the near field. The time-domain analysis of teleseismic data yields the source mechanisms, depths, and complexities of rupture of each earthquake. Both earthquakes occurred as shallow thrusts with centroid depths (6 to 7 km) and shallowly dipping fault planes that correspond well with the aftershock distributions obtained from a local survey run by the Canadian Geological Survey. The shallow nodal plane for the October 5 earthquake dips 30 ° to the WSW, while the shallow nodal planes of the subevents for the December 23 earthquake dip an average of 23 ° to the WSW. The October 5 earthquake has an impulsive initial rupture, followed by a weak subevent of longer duration but smaller moment release. The December 23 |
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