Michael W Webring (Former Employee)

No abstract available.

Potential field data (gravity and magnetic measurements) are both useful and costeffective tools for many geologic investigations. Significant amounts of these data are traditionally in the public domain. A new magnetic database for North America was released in 2002, and as a result, a cooperative effort between government agencies, industry, and universities to compile an upgraded digital gravit

The North American gravity database together with databases from Canada, Mexico, and the United States are being revised to improve their coverage, versatility, and accuracy. An important part of this effort is revision of procedures and standards for calculating gravity anomalies taking into account our enhanced computational power, modern satellite-based positioning technology, improved terrain

Gravity anomalies have become an important tool for geologic studies since the widespread use of high-precision gravimeters after the Second World War. More recently the development of instrumentation for airborne gravity observations, procedures for acquiring data from satellite platforms, the readily available Global Positioning System for precise vertical and horizontal control, improved global

No abstract available.

The North American gravity database as well as databases from Canada, Mexico, and the United States are being revised to improve their coverage, versatility, and accuracy. An important part of this effort is revising procedures for calculating gravity anomalies, taking into account our enhanced computational power, improved terrain databases and datums, and increased interest in more accurately de

Discoveries from multi-beam sonar mapping and seismic reflection surveys of the northern, central, and West Thumb basins of Yellowstone Lake provide new insight into the extent of post-collapse volcanism and active hydrothermal processes occurring in a large lake environment above a large magma chamber. Yellowstone Lake has an irregular bottom covered with dozens of features directly related to hy

A concerted effort is underway to prepare a substantially upgraded digital gravity anomaly database for the United States and to make this data set and associated usage tools available on the internet. This joint effort, spearheaded by the geophysics groups at the National Imagery and Mapping Agency (NIMA), University of Texas at El Paso (UTEP), U.S. Geological Survey (USGS), and National Oceanic

This publication includes maps, grids, and flightline databases of a detailed aerial survey and maps and grids of satellite data in Berrien County, Michigan. The purpose of the survey was to map aquifers in glacial terrains. This was accomplished by using a DIGHEMVRES mufti-coil, mufti-frequency electromagnetic system supplemented by a high sensitivity cesium magnetometer and 256-channel spectrome

A simplified three-dimensional model for the island of Hawai'i, based on 3300 gravity measurements, provides new insights on magma pathways within the basaltic volcanoes. Gravity anomalies define dense cumulates and intrusions beneath the summits and known rift zones of every volcano. Linear gravity anomalies project southeast from Kohala and Mauna Kea summits and south from Hualālai and Mauna Lo

No abstract available.

Magnetic forward models of the Cement oil field, Oklahoma, were generated to assess the possibility that ferrimagnetic pyrrhotite related to hydrocarbon seepage in the upper 1 km of Permian strata contributes to aeromagnetic anomalies at Cement. Six bodies having different magnetizations were constructed for the magnetic models, based on geology and on petrologic and geochemical results, supplemen