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A major goal of USArray was to collect detailed seismic images of the North American lithosphere. The data collected from USArray was integrated with geologic observations made on the Earth's surface to help determine the geologic history of North America, as well as to better understand that geologic processes that are at work today. [1] [2] [3]
The exploration of North America by European sailors and geographers was an effort by major European powers to map and explore the continent with the goal of economic, religious and military expansion. The combative and rapid nature of this exploration is the result of a series of countering actions by neighboring European nations to ensure no ...
Exploration geophysics is an applied branch of geophysics and economic geology, which uses physical methods at the surface of the Earth, such as seismic, gravitational, magnetic, electrical and electromagnetic, to measure the physical properties of the subsurface, along with the anomalies in those properties.
The Juan de Fuca plate is subducting northeastward under the North American plate. Nonvolcanic, episodic tremor was first identified in southwest Japan in 2002. [ 2 ] Shortly afterwards, the Geological Survey of Canada coined the term "episodic tremor and slip" to characterize observations of GPS measurements in the Vancouver Island area. [ 3 ]
Reflection seismology (or seismic reflection) is a method of exploration geophysics that uses the principles of seismology to estimate the properties of the Earth's subsurface from reflected seismic waves. The method requires a controlled seismic source of energy, such as dynamite or Tovex blast, a specialized air gun or a seismic
Near-surface geophysics is the use of geophysical methods to investigate small-scale features in the shallow (tens of meters) subsurface. [1] It is closely related to applied geophysics or exploration geophysics. Methods used include seismic refraction and reflection, gravity, magnetic, electric, and
Seismic refraction is a geophysical method for characterizing subsurface geological features. It operates on the principle that seismic waves —specifically P-waves and S-waves —refract, or bend, when they encounter layers with varying seismic velocities.
Seismic waves are recorded on geophones. Seismic methods are split up into three different methods, reflection, refraction, and surface wave, based on the physical property of the waves being considered. The reflection method looks at reflected energy from sharp boundaries to determine contrasts in density and velocity. Reflections methods are ...