Optical Fiber Interferometric Sensors

The contributions presented in this book series portray the advances of the research in the field of interferometric photonic technology and its novel applications. The wide scope explored by the range of different contributions intends to provide a synopsis of the current research trends and the state of the art in this field, covering recent technological improvements, new production methodologies and emerging applications, for researchers coming from different fields of science and industry. The manuscripts published in the Special issue, and re-printed in this book series, report on topics that range from interferometric sensors for thickness and dynamic displacement measurement, up to pulse wave and spirometry applications

Seismic Waves

The importance of seismic wave research lies not only in our ability to understand and predict earthquakes and tsunamis, it also reveals information on the Earth's composition and features in much the same way as it led to the discovery of Mohorovicic's discontinuity. As our theoretical understanding of the physics behind seismic waves has grown, physical and numerical modeling have greatly advanced and now augment applied seismology for better prediction and engineering practices. This has led to some novel applications such as using artificially-induced shocks for exploration of the Earth's subsurface and seismic stimulation for increasing the productivity of oil wells. This book demonstrates the latest techniques and advances in seismic wave analysis from theoretical approach, data acquisition and interpretation, to analyses and numerical simulations, as well as research applications. A review process was conducted in cooperation with sincere support by Drs. Hiroshi Takenaka, Yoshio Murai, Jun Matsushima, and Genti Toyokuni

Understanding Acoustics

This open access textbook, like Rayleigh’s classic Theory of Sound, focuses on experiments and on approximation techniques rather than mathematical rigor. The second edition has benefited from comments and corrections provided by many acousticians, in particular those who have used the first edition in undergraduate and graduate courses. For example, phasor notation has been added to clearly distinguish complex variables, and there is a new section on radiation from an unbaffled piston. Drawing on over 40 years of teaching experience at UCLA, the Naval Postgraduate School, and Penn State, the author presents a uniform methodology, based on hydrodynamic fundamentals for analysis of lumped-element systems and wave propagation that can accommodate dissipative mechanisms and geometrically-complex media. Five chapters on vibration and elastic waves highlight modern applications, including viscoelasticity and resonance techniques for measurement of elastic moduli, while introducing analytical techniques and approximation strategies that are revisited in nine subsequent chapters describing all aspects of generation, transmission, scattering, and reception of waves in fluids. Problems integrate multiple concepts, and several include experimental data to provide experience in choosing optimal strategies for extraction of experimental results and their uncertainties. Fundamental physical principles that do not ordinarily appear in other acoustics textbooks, like adiabatic invariance, similitude, the Kramers-Kronig relations, and the equipartition theorem, are shown to provide independent tests of results obtained from numerical solutions, commercial software, and simulations. Thanks to the Veneklasen Research Foundation, this popular textbook is now open access, making the e-book available for free download worldwide. Provides graduate-level treatment of acoustics and vibration suitable for use in courses, for self-study, and as a reference Highlights fundamental physical principles that can provide independent tests of the validity of numerical solutions, commercial software, and computer simulations Demonstrates approximation techniques that greatly simplify the mathematics without a substantial decrease in accuracy Incorporates a hydrodynamic approach to the acoustics of sound in fluids that provides a uniform methodology for analysis of lumped-element systems and wave propagation Emphasizes actual applications as examples of topics explained in the text Includes realistic end-of-chapter problems, some including experimental data, as well as a Solutions Manual for instructors. Features “Talk Like an Acoustician“ boxes to highlight key terms introduced in the text

Dunedin rock and roll: 3D seismic wave velocity modelling for seismic hazard analysis.

Earthquake hazards are significant in New Zealand. Many active faults are known to be close to urban areas, and damaging earthquakes have been known to occur on previously unknown faults (such as the Mw~7.1 Darfield earthquake of September 2010). The potential for a large earthquake on the Akatore Fault represents a significant seismic hazard to Dunedin City. The Akatore Fault may be within 15~km of the city, and paleoseismological studies suggest the fault may be in a period of heightened activity. Determining the geometry of the Akatore Fault is key to seismic hazard analysis in South Dunedin, as is ground motion prediction. As Dunedin has not experienced a large earthquake since it was settled in 1840, the best way to quantify ground motion is through earthquake ground motion simulation. This study aims to investigate the geophysical properties of rocks and sediments pertinent to 3D ground motion simulations for an Akatore Fault earthquake event in Dunedin City and contribute to determining the geometry of the Akatore Fault. New data acquired as a part of this study include three strategically placed seismic lines. A seismic line was collected across the Kaikorai Stream estuary, intersecting a proposed onshore location of the Akatore Fault. Two seismic lines were collected in South Dunedin. The data were processed to produce near-surface velocity models, stacked reflection profiles and stacking velocity models. The stacked profiles were interpreted in terms of mapped stratigraphic and basement geological units. The stacked reflection profile at Kaikorai Estuary contained no evidence of the Akatore Fault extending onshore. This sets an upper limit on the fault's length for future hazard analysis. Active source and passive surface wave data were collected at four sites across South Dunedin and analysed to estimate the near-surface S-wave velocity profile. Surface wave data were extracted from existing seismic lines, analysed, and compared to the dedicated active source seismic surveys to assess the potential for inversion. The data were found to be too low quality to invert alone but could be used in conjunction with MASW data collected at the same site. Gravity data collected across South Dunedin by Lutter (2018) was reprocessed to produce a fence diagram of 2D profiles following significant roads. These were used to create a surface between the low-density late Quaternary sediments and the higher density Dunedin sequence sediments. Ambient seismic vibrations recorded across South Dunedin were used to produce Horizontal to Vertical Spectral Ratio (HVSR) curves which were used to identify site period. The HVSR peaks were analysed in conjunction with the gravity data and the S-wave information to estimate the thickness of the soft sediments overlying the rocks of the Dunedin sequence below. The data collected in this study, existing mapped contacts, and borehole data were used to build a 3D geological model of the path between the Akatore Fault and Dunedin City. The velocities of the units were informed, where possible, by the P-wave stacking velocities used in seismic lines collected. S-wave velocities were constrained in the near surface with surface wave methods. For deeper units s-wave velocities were calculated using empirical equations. This study has collected and prepared the data and models required to characterise the path and site used in 3D ground motion simulations. This is a significant step forward concerning earthquake hazard analysis in Dunedin

Ocean Noise

Scientific and societal concern about the effects of underwater sound on marine ecosystems is growing. While iconic megafauna was of initial concern, more and more taxa are being included. Some countries have joined in multi-national initiatives to measure, monitor and mitigate environmental impacts of ocean noise at large, trans-boundary spatial scales. Approaches to regulating ocean noise change as new scientific evidence becomes available, but may also differ by country. The OCEANOISE conference series has provided a platform for the exchange of scientific results, management approaches, research needs, stakeholder concerns, etc. Attendees have represented various sectors, including academia, offshore industry, defence, NGOs, consultants and government regulators. The published articles in the Special Issue cover a range of topics and applications central to ocean noise