Origins of blade-like dikes in volcanic rift zones

TitleOrigins of blade-like dikes in volcanic rift zones
Publication TypeGovernment Report
Year of Publication1987
AuthorsRubin A.M, Polland D.D
Series TitleVolcanism in Hawaii
PublisherUS Geological Survey Professional Paper
Report Number1350

Seismic and geodetic data have demonstrated that dikes in the rift zones of Kilauea Volcano in Hawaii and Krafla Volcano in Iceland are typically intruded laterally from a central magma reservoir and acquire a blade-like form. A remarkable feature of many such dikes is that they propagate at shallow depths for 10s of km without erupting. Using concepts of fracture mechanics, we can specify the conditions necessary for this type of growth. A dike will propagate if the stress-intensity factor at the dike tip exceeds a critical value, known as the fracture toughness of the host rock. An increase in the rift-zone fracture toughness with depth could limit the depth to which dikes extend, but little existing evidence supports this possibility. We find that several geological processes could contribute to a distribution of the stress-intensity factor along the dike perimeter that would promote the development of a blade-like form.-from Authors