Microearthquake measurements near South Sebec, Maine, 1989-1990

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Earthquake monitoring in Maine since 1975 by the ten-station Weston Observatory network indicates a high concentration of earthquakes between the towns of Milo and Dover-Foxcroft. This regional network is capable of detecting events having magnitudes greater than 2.0 with a nominal location resolution of 3-5 km. Earlier literature reports and sparser networks indicate that the area has been active since at least the early 1800’s. As a result of these observations, an array of portable seismographs was deployed in the epicentral region during the summers of 1989 and 1990. It was anticipated that this deployment would capture a number of events (including many below the threshold of the regional network) and would better characterize the seismicity of the area. Specifically, we sought to determine the locations, depths, and focal mechanisms for a number of events. During the study, 73 earthquakes were identified and for 28 of these there was sufficient data to calculate a hypocenter. In this report, we present a compilation of our observations. Analysis of these results are published elsewhere (Doll et al., in preparation).

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  • Report


  • critical issues, database publication, earthquake, hazards, maine