The classic concepts of fluid transport derived for sedimentary environments are generally not applicable to the study of magmatic transport. High fluid viscosity and negligible rock permeability should preclude magma transport, yet dikes, sills, and other intrusive features are commonly observed. Relationships between intrusive units and regional paleo-stress fields are well described, but the dynamic interactions between igneous fluid and competent rock that ultimately produce magma intrusions are not. Elevated seismicity is often observed in conjunction with volcanic activity, and is generally thought to indicate magmatic intrusion.

This study examined the unique information that seismic data can provide about magmatic processes as they occur. Specifically, methods for deriving transport volume from fluid induced seismicity were evaluated. An approach proposed by Herbert Shaw linked total scalar seismic moment release and source region volume distortion. This relationship was tested using data from various fluid injection experiments by comparing observed seismicity with injected fluid volume. A second method examined seismic events from an earthquake swarm near the Yellowstone caldera for evidence of tensile-crack source mechanisms, which couldindicate igneous intrusion. Similar investigations have been successfully conducted using larger magnitude events. The Yellowstone swarm events were too small for traditional approaches, but were appropriately sized to assess the suitability of a different inversion technique for characterizing smaller events. A technique for improving the quality of the seismic dataset is also discussed. After further development, the techniques described may provide additional constraints on rates of active magma transport in volcanic areas.

The results obtained by this study were generally consistent with predictions of the McGarr-Shaw method, and have illuminated the additional considerations that must be addressed when testing the relationship using aqueous fluid injection rather than magmatic intrusion. Analysis of non-double-couple (NDC) events during earthquake swarms revealed that the currently deployed seismic network does not provide the coverage necessary to examine events of such low magnitude. Conducting a proper evaluation of the NDC inversion technique for inferring fluid transport will require additional broadband seismometer deployment at Yellowstone, or the selection of a new study area.