Applied High-Resolution Geophysical Methods: Offshore by Peter K Trabant

By Peter K Trabant

The self-discipline encompassing using high-resolution geophysics for acquiring geoengineering survey information has developed speedily during the last many years to turn into an interdisciplinary topic encompassing the fields of Geophysics, engineering, geology, marine geology, oceanography, and civil engineering. whereas high-resolution geophysical surveys are typically played offshore this present day, this has been so purely because the overdue Sixties. High-resolution geophysical tools are hired within the offshore atmosphere to procure a finished photograph of the sea-floor mor­ phology and underlying shallow stratigraphy. the aim of the survey tools is to help within the layout and set up of bottom-supported constructions similar to drilling and creation systems and pipelines. Drilling constructions and pipelines of metal and/or concrete became behemoths with appreciate to their measurement and the complexity in their layout which will face up to, for sessions of as much as twenty-five years, an incredibly harsh atmosphere, together with hurricane waves, robust currents, volatile sea­ flooring stipulations, and nice water depths. it really is for this reason of paramount significance that the geometry and actual homes of the ocean flooring be good understood so that it will offer an sufficient beginning for the layout lives of such buildings. On land, engineering origin info frequently will be acquired through visual view inspection and shallow borehole info, yet offshore the presence of the water column locations sure constraints on geoengineering investigations. High-resolution geophysical equipment hired within the acquisition of geoengineering facts offshore are outlined because the use of seismic resources and receivers that function at acoustic frequencies more than a hundred Hz.

Show description

Read Online or Download Applied High-Resolution Geophysical Methods: Offshore Geoengineering Hazards PDF

Similar conservation books

The New Consumers: The Influence Of Affluence On The Environment

Whereas overconsumption via the constructed world's approximately 1000000000 population is an abiding challenge, one other one thousand million more and more prosperous "new shoppers" in constructing international locations will position extra traces at the earth's assets, argue authors Norman Myers and Jennifer Kent during this vital new ebook.

Biodiversity: Exploring Values and Priorities in Conservation

Biodiversity has turn into a buzzword within the environmental circulate and in technological know-how, and is more and more being taught in collage measure classes. This new textual content is designed as a primer, giving non-specialists an creation to the historic context, present debates, and ongoing study during this topic.

Thorium: energy cheaper than coal

Thorium strength might help money CO2 and worldwide warming, minimize lethal pollution, supply inexhaustible strength, and elevate human prosperity. Our international is beset by way of worldwide warming, toxins, source conflicts, and effort poverty. thousands die from coal plant emissions. We battle over mideast oil. meals provides from sea and land are threatened.

Extra resources for Applied High-Resolution Geophysical Methods: Offshore Geoengineering Hazards

Example text

20 20 (/) (") J>. , 3 30 .. 6 Typical diffraction pattems from a pipeline and shallow gas pockets as revealed on a 14-kHz subbottom profiler recording off the Mississippi River delta. ) The resolution of a given seismic reflection system is the ability to distinguish between adjacent or overlying strata. The ability of a given system to resolve a particular unit is a function of the source frequency and the receiver/recorder system, and its ability to display a seismic reflector. While mostly a function of the frequency, other factors must also be taken into consideration, such as the thickness of the reflecting horizon and the sharpness of the boundary between the strata producing a reflection.

Returned echoes (reflections) from the sea floor, at the transmitted frequency, activate the transducer (piezo-electric effect) and generate an electronic pulse within the receiver of the echo sounder. The received echopulse may be very weak, depending upon transmitted power, water 4. 6 Digital/analog echo souoder electronic block diagram. ) depth, and the acoustic reflectivity of the sea floor, and must therefore be filtered in order to increase the signal-to-noise ratio, and amplified for display on the recorder by the sweeping stylus, which has moved a distance proportional to the water depth.

RECORDER PRECISION The accuracy of the depths recorded is mainly a function of the time base employed to drive the stylus belt or the digital sampling counter. Thus, an 4. Hz record depicting effect of heave compensator. , 58 Hz instead of 60Hz). On the other hand, when very high time base frequencies are used, such as in digital- and crystal-based systems, apower supply error of a few Hz is not significant. MOTION COMPENSATORS Heave- and motion-compensated echo sounders have been developed for precision bathymetric work where the effects of a survey vessel's motion, such as roll, pitch and heave, would produce poor estimates of the actual water depths.

Download PDF sample

Rated 4.39 of 5 – based on 10 votes