IRIS Seismographs in Schools recordings of the Magnitude 2.6 Earthquake located beneath Portland, Oregon, on November 6, 2006, at 05:34:35 UTC.
John C. Lahr, Jenda Johnson, and Robert Butler (Revised 11/26/2006)
As part of the Portland Public School’s 2006 Summer Science Institute, which was organized Portland’s Science Curriculum Specialist, Roy Chambers, and University of Portland Professor Robert Butler, teachers from twelve schools participated in a two-day seismology workshop in June. The focus of the workshop was learning enough about basic seismology in order to be able to operate a classroom seismic system. Six AS-1 seismic systems and associated PC computers were provided by the IRIS (Incorporated Research Institutions for Seismology) Education and Outreach Program.
The map above shows the current location of these six instruments, along with the location of the East Bank fault (purple), the Portland Hills fault (blue), and the November 6th earthquake. The systems located at Binnsmead (BSOR), Sellwood (SMOR), Winterhaven (WSOR), and
were working well and recorded this event. Although their clocks are not set accurately and the sample rate is only slightly higher than 6 Hz, records from these stations can be used to provide S minus P times and first motions. The table below summarizes the date from these stations. The stations coordinates could still be refined to agree with the placement of the instrument within the school building. The polarity of stations BSOR, SMOR, and WSOR was checked on November 9, 2006.
Binnsmead (BSOR) / 45.506540N, 122.574760W 82m / Compression / 2.3 or 3.4
Sellwood (SMOR) / 45.46268N, 122.64970W 31m / Compression / 1.8
Winterhaven (WSOR) / 45.4949N, 122. 65096W 15m / Compression / Uncertain
Portsmouth (PSOR) / 45.5843N, 122 .719750W 38m / Emergent Compression / Uncertain
Madison (MAOR) / 45.5426N, 122.58003W 72 m / No record
Meek ProTech (MEOR) / 45.55851N, 122.62178W 59 m / No record
Binnsmead (BSOR) unfiltered record.
A high-pass filter with 1.6 second-period corner has been applied to the Binnsmead (BSOR) record. The S minus P time for the picks shown is 3.4 seconds.
A less steep high-pass filter with 1.6 second-period corner has been applied to the Binnsmead (BSOR) record. The S minus P time for the picks shown is 2.3 seconds. The first motion is impulsive compression.
Sellwood Middle School (SMOR) unfiltered record.
Sellwood Middle School (SMOR) unfiltered record with S minus P interval of 1.8 seconds. The first motion is impulsive compression.
Winterhaven K-8 School (WSOR) unfiltered record. The first motion is impulsive compression.
Portsmouth (PSOR) unfiltered record.
Portsmouth (PSOR) after application of a high-pass filter with 1.6 second-period corner.
Acknowledgements
Many thanks are due to Roy Chambers and the teachers who have been running these seismic stations in their classrooms. The teachers include Joanne Barda, Edwin Wack, Gerilyn Nichols, Tom Bright, Ric Oleksak, Rod Kitson, Joanne Barta, and Edwin Wack.