Holly F. Ryan — Page 2 | Geology Reports

USGS1987

Recording and processing procedures for multi-channel seismic-reflection data collected in the western Ross Sea, Antarctica

During 1984, over 2300 km of multichannel seismic-reflection data were recorded by the U.S. Geological Survey in the western Ross Sea and Iselin Bank regions. A temporary loss and sinking of the streamer led to increasing the streamer tow depth to 20 m, which resulted in some attenuation of frequencies in the 30-50 Hz range but no significant difference in resolution of the stacked data. Severe water bottom multiples were encountered and removed by dip-filtering, weighted stacking, and severe post-NMO muting.

Book chapter↗

USGS1983

Maps showing aeromagnetic data and interpretation for the Kalmiopsis Wilderness, southwestern Oregon

The distinctive magnetic properties of the major rock types in the Kalmiopsis Wilderness of southwestern Oregon facilitate interpretation of aeromagenetic data. The region is composed of tectonic slices of magnetic ultramafic, gabboric, and other ophiolitic rocks faulted against the realitively nonmagnetic Dothan Formation, the equivalent of the Franciscan Complex of Western California. The sharp contacts between these rocks are manifested in the data by abrupt contrases in the nature of the magnetic anomalies which provide insights into the structural relations of major geologic elements. Most individual anomalies in this area are caused by known geologic boundaries or topographic features; those that are not are of particular interest because they may reflect areas of increased or decreased magnetization associated with zones of minerlization.

Oregon↗