Layer | Fill | Outline |
---|
Map layers
Theme | Visible | Selectable | Appearance | Zoom Range (now: 0) |
---|
Fill | Stroke |
---|---|
Collaborating Authors
Results
Two coupled objectives for this decreased of the reflections. Thus, spatial sampling (source/receiver spatial sampling are more effective coherent noise spacing), because of its influence on the effectiveness of attenuation, and higher image resolution, both lateral and coherent noise attenuation, can have a strong effect on both vertical. We demonstrate, using field experiment results.
Summary CREWES, in conjunction with Husky Energy, Geokinetics, INOVA and Nanometrics, conducted a low-frequency 2D seismic experiment near Hussar, Alberta, Canada, in September of 2011. The purpose of the experiment was to study acquisition of low-frequency data in order to improve inversion results. Sources included three different Vibroseis units, and dynamite. Receivers on the ground were ION-sensor SM-7 10 Hz 3C geophones at 10 m station spacing, VectorSeis 3-C accelerometers at 10 m spacing, Sunfull 4.5 Hz 1C geophones at 20 m spacing, a partial line of SM-24 10 Hz high-sensitivity geophones at 20 m spacing, and Nanometrics compact broadband seismometers at 200 m spacing. Total receiver line length was 4.5 kilometers. On the last day of acquisition, a magnitude 6.3 earthquake occurred offshore Vancouver Island, British Columbia, Canada, approximately 1050 kilometers from the test line. The predominant frequency of earthquake arrivals was about 0.4 Hz, which is well out of the frequency range of 4.5 and 10 Hz geophones. However, the earthquake was recorded by all sensors that were part of the low-frequency experiment, and after correcting the data for geophone response, it is clear that data less than 1 Hz can be recorded on these geophones, for a sufficiently energetic source.
- North America > Canada > Alberta (0.35)
- North America > Canada > British Columbia (0.25)
Summary Approximately 42 line-km of high-fold reflection seismic data were recorded in and around the city of Christchurch, New Zealand, following a devastating Mw 6.3 earthquake on February 22, 2011. The goal of the seismic program was to map previously unknown faults in and around the city for hazard assessment and to assist in the post-earthquake recovery effort. 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.