Two problems in WKBJ theory: the interpolation of sampled velocity profiles and the use of frequency-dependent, complex velocities     

L. Neil Frazer 《Geophysical Journal International》1983,72(1):193-211

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Burial history of Late Neogene sedimentary basins on part of the New Zealand convergent plate margin     

PATRICIA Wells 《Basin Research》1989,2(3):145-160

Abstract Burial histories of Late Neogene sedimentary basins on the Wairarapa fold and thrust belt of the Hikurangi convergent plate margin (New Zealand) have been deduced from decompacted sedimentary columns and palaeo-waterdepths. These indicate that at least two major cycles of basement subsidence and uplift have occurred since 15 Ma. The older (15-10 Ma) cycle affected outer areas of the forearc. Subsidence, at a minimum rate of 0.5-0.6 mm/yr, was followed by rapid uplift. The subsequent (10 Ma to present) cycle affected a broad area of the inner forearc. Subsidence, at an average rate 0.33 mm/yr, was followed by uplift at an average rate of 0.5-1.5 mm/yr. Vertical movement is continuing, with uplift of the axial greywacke ranges and development of the Wairarapa Depression.
Palinspastic reconstructions of the inner forearc region indicate that basin development was characterized by a see-saw oscillation in basin orientation, with the axis of the basin and direction of basin tilt switching back and forth from east to west through time. A large-scale change in basin orientation took place around 2 Ma when the westernmost part of Wairarapa began to rise on the flanks of the rising Tararua Range, associated with the ramping of the Australian Plate up and over the subducted Pacific Plate. Loading of the forearc is unlikely to have been a significant cause of basement subsidence before this event. Earlier phases of basin development associated with basement subsidence and uplift may be related to a complex interplay of tectonic factors, including the westward migration of the subducted Pacific Plate as it passed beneath southern North Island during Miocene time, episodes of locking and unlocking of parts of the plate interface, and growth of the accretionary prism.  相似文献   

Theories of Underdevelopment: A Response to Reitsma     

Neil Smith 《The Professional geographer》1982,34(3):332-337

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Kirchhoff–Helmholtz reflection seismograms in a laterally inhomogeneous multi-layered elastic medium – II. Computations     

Mrinal K. Sen  L. Neil Frazer 《Geophysical Journal International》1985,82(3):415-437

Summary. High-frequency reflection and refraction seismograms for laterally variable multi-layered elastic media are computed by using the frequency domain elastic Kirchhoff–Helmholtz (KH) theory of Frazer and Sen. Both source and receiver wavefields are expanded in series of generalized rays and then elastic (KH) theory is applied to determine the coupling between each source ray and each receiver ray at each interface. The motion at the receiver is given as a series of integrals, one for each generalized ray. We use geometrical optics and plane wave reflection and transmission coefficients for rapid evaluation of the integrand. When the source or the receiver ray field has caustics on the surface of integration geometrical ray theory breaks down and this gives rise to singularities in the KH integrand. We repair this using methods suggested by Frazer and Sen.
Examples of reflection seismograms for 2-D structures computed by elastic KH theory are shown. Those for a vertical fault scarp structure are compared with the seismograms obtained by physical modelling. Then OBS data obtained from the mid-America trench offshore Guatemala area are analysed by computing KH synthetics for a velocity model that has been proposed for that area. Our analysis indicates the existence of a small low-velocity zone off the trench axis.
No head wave arrivals are obtained in our KH synthetics since we do not consider multiple interactions of a ray with an interface. The nearly discontinuous behaviour of elastic R/T coefficients near the critical angle causes small spurious phases which arrive later than the correct arrivals.  相似文献   

An Introduction to the Martian Grid System     

R. A. Wells 《Geophysical Journal International》1969,17(2):209-224

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Use of the spherical layer matrix in inhomogeneous media     

L. Neil FIazer 《Geophysical Journal International》1977,50(3):743-749

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Bringing in Race     

Olivia Mitchell  Neil Smith 《The Professional geographer》1990,42(2):232-234

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Structure and kinematics of the northern Simano Nappe, Central Alps, Switzerland     

Roger Rütti  Michael Maxelon  Neil S. Mancktelow 《Eclogae Geologicae Helvetiae》2005,98(1):63-81

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Comment on “An experimental study of oxygen isotope fractionation between inorganically precipitated aragonite and water at low temperatures” by G.-T. Zhou and Y.-F. Zheng     

Sang-Tae Kim  James R. O’Neil 《Geochimica et cosmochimica acta》2005,69(12):3195-3197

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Reversal of eutrophication following sewage treatment upgrades in the New River Estuary, North Carolina     

Michael A. Mallin  Matthew R. McIver  Heather A. Wells  Douglas C. Parsons  Virginia L. Johnson 《Estuaries and Coasts》2005,28(5):750-760

The New River Estuary consists of a series of broad shallow lagoons draining a catchment area of 1,436 km², located in Onslow County, North Carolina. During the 1980s and 1990s it was considered one of the most eutrophic estuaries in the southeastern United States and sustained dense phytoplankton blooms, bottom water anoxia and hypoxia, toxic outbreaks of the dinoflagellatePfiesteria, and fish kills. High nutrient loading, especially of phosphorus (P), from municipal and military sewage treatment plants was the principal cause leading to the eutrophic conditions. Nutrient addition bioassay experiments showed that additions of nitrogen (N) but not P consistently yielded significant increases in phytoplankton production relative to controls. During 1998 the City of Jacksonville and the U.S. Marine Corps Base at Camp Lejeune completely upgraded their sewage treatment systems and achieved large improvements in nutrient removal, reducing point source inputs of N and P to the estuary by approximately 57% and 71%, respectively. The sewage treatment plant upgrades led to significant estuarine decreases in ammonium, orthophosphate, chlorophylla, and turbidity concentrations, and subsequent increases in bottom water dissolved oxygen (DO) and light penetration. The large reduction in phytoplankton biomass led to a large reduction in labile phytoplankton carbon, likely an important source of biochemical oxygen demand in this estuary. The upper estuary stations experienced increases in average bottom water DO of 0.9 to 1.4 mg l⁻¹, representing an improvement in benthic habitat for shellfish and other organisms. The reductions in light attenuation and turbidity should also improve the habitat conditions for growth of submersed aquatic vegetation, an important habitat for fish and shellfish.  相似文献