Microearthquake Reconnaissance Near Bully Creek, Oregon And Seismic Records, Chalk Butte And Bully Creek Areas

Two Sprengnether Meq-800 Seismographs Were Operated Side-By-Side In A Mercury Mine Adit Of Hope Butte, 5 1/2 Km Nnw Of Bully Creek School, Or About 20Km Nw Of Vale, Oregon (Figure 1). The Instruments Were Operated Between 11 - 19 September, 1975, And Produced Legible Records During About 90 Percent Of That Interval. Gains Of 90 To 96Db Were Utilized. Portions Of Some Records Were Obscured By Wind Noise And 60 Hz Ac. The Operator Was John Deymonaz. The Seismometers Were Spaced About 150M Apart In A Mine (Figure 2). The North One Was A Mark Products L-4C 1Hz Vertical Component Seismometer Planted In The Mine; The South Unit Was A 4 Hz Vertical Component Geophone Of Somewhat Lower Response Than The Former. Hope Butte Is Composed Of Silicified Chalk Butte Sediments. Throughout Historic Time, No Earthquakes Have Been Recorded From The Chalk Butte Area. The Nearest Recorded Earthquake Was Of A Magnitude 1.8 Near Vale, 16 Kilometers To The North, On 8 November 1975. A High-Gain Microseismic Network With A Detection Threshold Below Magnitude 0 Was Operated For A Period Of 10 Days In February, 1975, By Microgeophysics Corporation. The Nine Stations, Deployed Between Vale And Chalk Butte, Detected No Microearthquakes. Their Conclusion Is: "Seismicity As Recorded In This Survey Poses No Threat To The Structures Or Works Of Man". Egi Reference Number Gl04926_4

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Citation Date 1976-03-12T00:00:00

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Original ID C0FE9280272E498D9EDFB5976B307E0B
Index Date 2014-06-17T12:37:29
Original Format ISO-USGIN
Original Version 1.2


Name A. L. Lange
Email sbivens@egi.utah.edu

Geographic Extent

North Bound 46.3
South Bound 42
East Bound -116.46
West Bound -124.61