Diving behaviour of short-finned pilot whales is often described by two states; deep foraging and shallow, non-foraging dives. However, this simple classification system ignores much of the variation that occurs during subsurface periods. We used multi-state hidden Markov models (HMM) to characterize states of diving behaviour and the transitions between states in short-finned pilot whales. We ...

Shallow Radar (SHARAD) on board NASA’s Mars Reconnaissance Orbiter has successfully detected tens of reflectors in the subsurface of the north polar layered deposits (NPLD) of Mars. Radar reflections are hypothesized to originate from the same material interfaces that result in visible layering. As a first step towards verifying this assumption, this study uses signal analyses and geometric com...

Geophysical techniques coupled with the modern computer workstation have not been widely used in environmental geology. The Kansas Geological Survey is investigating the application of the computer workstation in a number of projects underway that involve environmental questions and problems associated with salt dissolution. The computer workstation provides an efficient approach to integrate g...

Non-destructive detection and evaluation of invisible cracks in metal structures is an important matter in several critical environments including ground transportation, air transportation and power plants. In this paper, a high-Q near-field Microwave probe is designed and fabricated using defected ground structures for surface and subsurface crack detection in metal structures. For this purpos...

[1] We assess the sensitivity of a subsurface thermodynamic model to the depth of its lower-boundary condition. Analytic solutions to the one-dimensional thermal diffusion equation demonstrate that boundary conditions imposed at shallow depths (2–20 m) corrupt the amplitudes and phases of propagating temperature signals. The presented solutions are for: 1) a homogeneous infinite half-space driv...

  In this study, a new method for joining aluminum tubes in subsurface structures using steel converting and aluminum welding are presented and reviewed. But near the weld area is under high thermal cycle and will cause residual stresses in heat affected zone. Therefore for assessment of proposed connection from the perspective of residual stress by using the finite element method welding of tu...

The long-term objective of the GEOCLUTTER program is to understand the causes and implications of geologic clutter (reverberation) in a geologically well-characterized shallow-water environment. The original field area selected for the GEOCLUTTER program was the mid-outer continental shelf off New Jersey, USA. The New Jersey margin was chosen for the GEOCLUTTER study because the bathymetry and ...

The common goals of the Geoclutter program are to: (1) understand the acoustic scattering process in shallow water, in order to design physics-based signal processing algorithms to distinguish acoustic returns originating from naturally-occurring features on the world's continental shelves (e.g., iceberg scours, shallow gas accumulations, outcrops of high-amplitude shallow subsurface reflectors...