Location and Mechanism of Very Long Period Tremor During the 2008 Eruption of Okmok Volcano from Interstation Arrival Times

We describe continuous, very long period (VLP) tremor that occurred during the 2008 eruption of Okmok Volcano, Alaska. Due to its low frequency content in band from the 0.2–0.4 Hz, the wave field of the VLP tremor is relatively free of path effects. From continuous recordings of the VLP tremor on 2 three-component broadband and 3 single-component short‐period instruments, we devise a method to locate the epicenter of the tremor based on interstation arrival times computed with cross correlation. We find the epicenter since the vertical and radial components of the VLP tremor wave field are dominated by Rayleigh waves and the time shifts are related to lateral propagation. Over the 4 h period studied, this procedure yields a location NNW of Cone D, close to the new cone built over the course of the eruption. Similar analysis using the transverse horizontal components from the 2 three‐component broadband instruments yields strong constraints on the source mechanism of the VLP tremor. We observe an anomalous interstation arrival time due to the existence of a nodal plane in the Love wave radiation pattern. The orientation of a compensated linear vector dipole (CLVD) source estimated from the transverse components closely aligns with the regional maximum horizontal stress direction. The depth of the CLVD source is constrained by matching the vertical components to the Rayleigh wave radiation pattern at all five stations. We find the VLP tremor source depth to be 2 km BSL, positioned between the magma chamber at Okmok (\u3e3 km BSL) and the surface

Infrasonic Ambient Noise Interferometry From Correlations of Microbaroms

We show that microbaroms, continuous infrasound fluctuations resulting from the interaction of the ocean with the atmosphere, have long-range correlation properties that make it possible to estimate the impulse response between two microphones from passive recordings. The processing is analogous to methods employed in the emerging field of ambient noise seismology, where the random noise source is the ocean coupling with the solid Earth (microseisms) instead of the atmosphere (microbaroms). We find that timedependent temperature fields and temperature inversions determine the character of infrasonic impulse responses at Fourpeaked Volcano in Alaska. Applications include imaging and monitoring the gross structure of the Earth’s atmospheric boundary layer

Back to Reality: A Study of Reality Television Tourism

With movies and television providing entertainment in almost every American household, reality programming has become an integral part of the marketing industry today. This form of entertainment has influenced viewers and marketers alike as the number of programs have increased on nearly every network. This paper explores the gap in available academic research as to how this explosion in programming affects tourism to the locations presented in films and television shows. Data was collected by means of a self-administered survey completed through Qualtrics; snowball sampling was used. The survey was posted and completed through reality television message boards and blogs and via social media. Data analysis involved multiple statistical measurements but relied primarily on Structural Equation Modeling. Components adapted from Crompton’s push/pull model in additional to others introduced items provided the base work for the analysis. This study found that the primary viewer of reality television was female, thirty years-of-age or older, well educated, married, and at a higher income level. The findings of the study exhibited three factors that influenced consumer likelihood of visiting a reality television destination. These were: Personal Involvement, Destination Image, and Motivation. This study provides traditional print marketers, destination marketers, film and television producers as well as the destination location, much valuable and useful information. The data obtained provides an opportunity to capitalize upon different mediums through the use of advertisements and specified promotions that are directly related to locations and/or destinations portrayed within the program. It also provides a look at the consumers of the programming and what would attract the viewers to a location. KEYWORDS: Reality television tourism, Push/Pull, structural equation modeling, film-induced tourism, destination image, travel and touris

Autism, Social Comprehension, and Cognitive Impenetrability

Autism is a neurodevelopmental disorder featuring severe social and communicative deficits. Cognitive impenetrability is the inability of systems to be affected by an individual’s beliefs and desires. Individuals with autism have delayed performance on mindreading tasks. Mindreading is the interpretation of others which enables successful social interactions. This task performance is not correlated with everyday social function in autism. These deficits are in contrast with general intelligence and reasoning abilities within the normal range, resistant to cognitive behavioral training, and partially attributable to atypical social predispositions. This suggests individuals with autism perform social tasks differently than typicals. I argue that this mindreading deficit is cognitively impenetrable, then position this deficit within a theoretical framework, enactivism, emphasizing cognitive embodiment and inseparability of social comprehension and action. This framework helps explain the cognitive impenetrability of these social deficits by locating failure to penetrate in individuals\u27 failure to properly interact with the environment

Perturbational and nonperturbational inversion of Rayleigh-wave velocities

The inversion of Rayleigh-wave dispersion curves is a classic geophysical inverse problem. We have developed a set of MATLAB codes that performs forward modeling and inversion of Rayleigh-wave phase or group velocity measurements. We describe two different methods of inversion: a perturbational method based on finite elements and a nonperturbational method based on the recently developed Dix-type relation for Rayleigh waves. In practice, the nonperturbational method can be used to provide a good starting model that can be iteratively improved with the perturbational method. Although the perturbational method is well-known, we solve the forward problem using an eigenvalue/eigenvector solver instead of the conventional approach of root finding. Features of the codes include the ability to handle any mix of phase or group velocity measurements, combinations of modes of any order, the presence of a surface water layer, computation of partial derivatives due to changes in material properties and layer boundaries, and the implementation of an automatic grid of layers that is optimally suited for the depth sensitivity of Rayleigh waves

Nonperturbational surface-wave inversion: A Dix-type relation for surface waves

We extend the approach underlying the well-known Dix equation in reflection seismology to surface waves. Within the context of surface wave inversion, the Dix-type relation we derive for surface waves allows accurate depth profiles of shear-wave velocity to be constructed directly from phase velocity data, in contrast to perturbational methods. The depth profiles can subsequently be used as an initial model for nonlinear inversion. We provide examples of the Dix-type relation for under-parameterized and over-parameterized cases. In the under-parameterized case, we use the theory to estimate crustal thickness, crustal shear-wave velocity, and mantle shear-wave velocity across the Western U.S. from phase velocity maps measured at 8-, 20-, and 40-s periods. By adopting a thin-layer formalism and an over-parameterized model, we show how a regularized inversion based on the Dix-type relation yields smooth depth profiles of shear-wave velocity. In the process, we quantitatively demonstrate the depth sensitivity of surface-wave phase velocity as a function of frequency and the accuracy of the Dix-type relation. We apply the over-parameterized approach to a near-surface data set within the frequency band from 5 to 40 Hz and find overall agreement between the inverted model and the result of full nonlinear inversion