Hey guys! Sorry for the long hiatus. Things got quite busy after I returned from the boat. Also, the cable which I need to download photos off my camera mysteriously went missing while I was on the ship. Anyways, photos and more stuff about the boat will be coming as soon as a replacement cable arrives later this week.
For now, however, I'm going to tell you a little bit about the data I have been/will be working with. My project is focussed on resolving inconsistencies in the locations of a swarm of earthquakes which occurred over four days in 2008 near Explorer Ridge off the coast of Vancouver Island. The earthquakes themselves have been located by the Canadian National Seismic Network (CNSN), the Advanced National Seismic System (ANSS), and by Dr. Dziak's group using data from the Navy's Sound Surveillance System (SOSUS). Both the CNSN and ANSS locations are derived from land-based seismometer networks in Canada and the US respectively. The SOSUS network is an array of hydrophones, originally designed to detect foreign submarines, which also record acoustic waves generated by submarine earthquakes. Due to its national security purpose, the data from the SOSUS hydrophones is classified, hence I will only be examining the locations reported by the Dziak group.
Fortunately the seismographs for the CNSN and ANSS locations are in the public domain. P and S arrival picks have already been made for the Canadian data and I hope to be able to use those picks in my analysis. The instruments in the Canadian array are about half broadband and half extremely short period and preprocessing has already been done. In case you're not well versed in seismometer jargon, broadband and and extremely short period refer to which range of the seismic spectrum the instruments "hear". By analogy you can think about how human ears can pickup sounds in the range from 12 Hz to 20 kHz whereas bat ears are most sensitive to higher pitched sounds in the 15 kHz to 90 kHz range (see http://en.wikipedia.org/wiki/Hearing_range). Since these datasets are public it is possible that many other researchers have used them. However, to my knowledge no one else has published about these earthquakes using this dataset.
In addition to the land-based networks, I have been examining data from ocean bottom seismometers that were part of the Central Oregon Locked Zone Array (COLZA) experiment. This data, too, is publicly available but I am unaware of anyone outside of our lab group using it to examine these earthquakes. A previous IRIS intern in my lab has gone through the data and examined the T-phases (acoustic waves generated by submarine earthquakes which travel through the ocean). I will be filtering and processing the data and hope to be able to glean some insights about its usefulness in relocating these types of earthquakes.
Okay, that's pretty much it for my datasets. As soon as the camera cable comes in I'll upload photos from the boat and the mountain we climbed this weekend!
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