Crustal Deformation Release, Failure and Tilts in Alaska
Abstract
The main purpose of the contract was to gain insight into the crustal failure mechanism and the associated source phenomenon in Alaska. This effort includes the operation of the short-period telemetry network and the three long- period borehole installations used for the measurements of crustal tilts. Through the telemetry system there is now on hand an almost complete record on the seismicity of Central Alaska, covering a total of four years, and of much higher accuracy than was hitherto available. The operation of the borehole long- period seismometer has revealed tilts associated with earthquakes as small as magnitude 3, which are consistent with the tectonic stress axis, but do not seem to conform to elastic fault dislocation models. Analysis of literature suggests that Russian observations of the Vp/Vs ratio, diminishing by about 0.1 prior to larger earthquakes, can be explained by the decrease in Vp/Vs ratio due to micro-fracturing (observed in the laboratory) and theoretical as well as experimental work on Vp/Vs changed as a function of porosity.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1971
- Accession Number
- AD0719840
Entities
People
- Eduard Berg
Organizations
- University of Alaska Fairbanks