Handbook of Crack Opening Data

Basaltic feeder dykes in rift zones: geometry, emplacement, and effusion rates

“…In contrast to comparatively small wall-erosion effects on feeder-dyke thicknesses, the free-surface effect on feeder-dyke thicknesses is common. It follows from the fact that the opening or aperture of an extension fracture is normally greatest at the free surface because there the elastic constraints on the opening-displacement are partly removed (Gray, 1992;Gudmundsson et al, 2008). The same results as to the commonly observed widening of feeder-dykes towards the surface have been obtained in other studies (e.g., Geshi et al, 2010).…”

“…Here the overpressure (p o ) derives from the term in the brackets, and is partly due to the excess pressure p e in the source magma chamber of the dyke, and partly on the buoyancy term (ρ r − ρ m )g as defined above (note that the term is multiplied by the height or length L to get the proper units). The aperture is thus known to vary with overpressure, and can be modelled in various ways (e.g., Gudmundsson, 1986;Gray, 1992;Kusumoto et al, 2012). Currently, however, there are no available analytical models that allow the coupled changes in overpressure and aperture to be directly related to changes in volumetric flow rates during volcanic eruptions.…”

Geometry, structure and emplacement of mafic dykes in the Red Sea Hills, Sudan

“…It should be understood that large parts of a dyke swarm may be involved in the stress effects. Then dykes in that part act mechanically as a single overpressured fracture (Sneddon and Lowengrub, 1969;Gray, 1992), in which case the stress effects may extend to many tens (or perhaps hundreds) of kilometres to either side of that part of the swarm. For example, the maximum horizontal compressive stress trends subperpendicular to the nearest rift-zone segments in Iceland (Hast, 1973;Haimson and Rummel, 1982), and this stress field can be explained by emplacement of overpressured dykes in the rift zone (Gudmundsson et al, 1996).…”

“…11). Second, we measured the same lineaments, but took into account that if the nearby ends of segments are separated by less than around 10% of the segment lengths, the segments act mechanically essentially as a single fracture (Sneddon and Lowengrub, 1969;Gray, 1992). This applies particularly to the thicknesses of the dyke segments, or generally to the opening displacement of any type of extension fracture, and is valid even if the segments are unconnected at depth.…”

Development of a failure assessment diagram based method for engineering criticality assessment of CO2 transportation pipelines

“…Different sources for well-known geometries, crack shape and loading conditions are presented. [7][8][9][10][11] For certain conditions in which a solution cannot be derived from handbooks, other methods such as finite element analysis, weight function and multiple reference state weight function should be used. 12,13 With these methods, a combination of working load, transient thermal stresses, welding heat affected zone and residual stresses are considered to determine K I to be used in FAD analysis.…”