Crustal structure of the Island of Hawaii from seismic-refraction measurements

In August of 1964 the U. S. Geological Survey established seismic-refraction profiles along the northeast, southwest, and west coasts of the roughly triangular-shaped Island of Hawaii. Shots were fired at 10-km intervals along each coast from the U. S. Coast Guard Cutter CAPE SMALL and were recorded on shore by five refraction units spaced at approximately 25 km intervals along each coast. Most of these shots were also recorded on the 13 seismograph stations maintained on Hawaii by the U. S. Geological Survey's Hawaiian Volcano Observatory. These data were supplemented by recordings on the 13-station seismograph network and two mobile systems of three 500-ton chemical explosions deronated by the U. S. Navy on Kahoolawe as part of the SAILOR HAT program and by a re-evaluation of arrivals recorded on the seismograph network from seismic-refraction profiles shot off the northeast coast of Hawaii by Scripps Institution of Oceanography in 1962. Interpretation of the resulting seismograms suggests that the crust under Hawaii can be divided into two principal layers: (1) a basal layer 4 to 8 km thick with P-wave velocities of 7.0 to 7.2 km/sec, and (2) an upper layer 4 to 8 km thick in which P-wave velocities increase with depth from 1.8 to 3.3 km/sec at the surface to 5.1 to 6.0 km/sec at depth. The basal layer is probably the original oceanic crust under Hawaii plus the intrusive system associated with central vents and rift zones, and the upper layer is the accumulated pile of lava flows that form the bulk of the island. The crust along the northeast and southwest flanks of Kilauea is 11 to 12 km thick with P-wave velocities increasing in the upper layer from 1.8 km/sec at the surface to 5.1 km/sec at depth. The basal layer is 4 km thick and has a P-wave velocity of 7.1 km/sec. A 7.0-km/sec layer at depths of 3 to 5 km under the northeast flanks of Mauna Kea and Kohala Mountain masks first-arrival evidence for deeper structure, but secondary arrivals interpreted as reflections from the M discontinuity suggest that the underlying crust may be anywhere between 12 and 20 km thick. This shallow 7.0-km/sec layer is probably associated with the nearby rift zones of Kohala Mountain and Mauna Kea. The crust increases in thickness along the west coast of Hawaii from about 14 km under the flanks of Kohala Mountain and Hualalai to about 18 km under the flank of Mauna Loa. P-wave velocities along this coast increase with depth from 2.5 km/sec at the surface to 6.0 km/sec at about 10 km, and the lower 4 to 6 km of the crust has a P-wave velocity of about 7.2 km/sec. The upper mantle P-wave velocity under most of the island is 8.2 km/sec but may decrease to 8.1 km/sec under the southeast flank of Kilauea. Material with mantle-like P-wave velocity appears to bulge up under the summit of Kilauea to a depth as shallow as 10 or 11 km. Early P-wave arrivals associated with the summits and major rift zones of the volcanoes indicate that material with velocities as high as 7.0 km/sec approaches within 2 or 3 km of the surface under these structures and merges at depth with the 7.1- to 7.2-km/sec layer forming the base of the crust

An earth-flattening transformation for waves from a point source

An earth-flattening transformation is developed for wave-propagation problems that can be formulated in terms of uncoupled scalar Helmholtz equations. Through the transformation, wave problems in isotropic, spherically symmetric media with a specified radial heterogeneity can be expressed in terms of a flat geometry with a suitably vertical heterogeneity. The transformation is exact for homogeneous (no source) problems and is useful for normal mode studies. When a point source of waves is present, the earth-flattening transformation together with the Watson transform converts the reflected wave field from a sum over discrete, spherical eigenfunctions to an integral over continuous wave numbers in a flat geometry. The far-field form of this integral shares many properties with the Weyl integral and is useful for body-wave studies in a spherical earth

A note on the earth-stretching approximation for Love waves

Earth-flattening transformations provide an efficient means for computing Love-wave dispersion and torsional normal mode frequencies in radially heterogeneous, spherically symmetric earth models. These transformations involve simple algebraic sealing factors applied to solutions for SH waves in a layered half-space. They result in considerable computational savings over solutions expressed directly in spherical geometry. Several earth-flattening transformations for SH waves are described in the literature (Anderson and Toksöz, 1973; Sato, 1968; Biswas and Knopoff, 1970). Chapman (1973) has examined the general class of power-law earth-flattening transformations and their application to body-wave problems

The Components Of A Successful CEO Apology

Although most research suggests that apologies are associated with positive outcomes, the relationship can be equivocal. An apology’s effectiveness is highly dependent on whether certain components are present. The current study investigates the effectiveness of various apology components proposed by Boyd (2011). Twenty-five CEO apologies were coded for seven components: revelation, recognition, responsiveness, responsibility, remorse, restitution, and reform. These apologies were then shown to 151 participants who rated their willingness to forgive and trust the apologizers. All components were significant except for responsibility

Gene Ontology annotations: what they mean and where they come from

To address the challenges of information integration and retrieval, the computational genomics community increasingly has come to rely on the methodology of creating annotations of scientific literature using terms from controlled structured vocabularies such as the Gene Ontology (GO). Here we address the question of what such annotations signify and of how they are created by working biologists. Our goal is to promote a better understanding of how the results of experiments are captured in annotations, in the hope that this will lead both to better representations of biological reality through annotation and ontology development and to more informed use of GO resources by experimental scientists

Cross-Product Extensions of the Gene Ontology

The Gene Ontology is being normalized and extended to include computable logical definitions. These definitions are partitioned into mutually exclusive cross-product sets, many of which reference other OBO Foundry ontologies. The results can be used to reason over the ontology, and to make cross-ontology queries

Stepped care treatment delivery for depression: a systematic review and meta-analysis

The article has been accepted for publication and will appear in a revised form, subsequent to peer review and/or editorial input by Cambridge University Press, in Psychological Medicine, published by Cambridge University Press.Background In stepped care models patients typically start with a low-intensity evidence-based treatment. Progress is monitored systematically and those patients who do not respond adequately step up to a subsequent treatment of higher intensity. Despite the fact that many guidelines have endorsed this stepped care principle it is not clear if stepped care really delivers similar or better patient outcomes against lower costs compared with other systems. We performed a systematic review and meta-analysis of all randomized trials on stepped care for depression. Method We carried out a comprehensive literature search. Selection of studies, evaluation of study quality and extraction of data were performed independently by two authors. Results A total of 14 studies were included and 10 were used in the meta-analyses (4580 patients). All studies used screening to identify possible patients and care as usual as a comparator. Study quality was relatively high. Stepped care had a moderate effect on depression (pooled 6-month between-group effect size Cohen's d was 0.34; 95% confidence interval 0.20–0.48). The stepped care interventions varied greatly in number and duration of treatment steps, treatments offered, professionals involved, and criteria to step up. Conclusions There is currently only limited evidence to suggest that stepped care should be the dominant model of treatment organization. Evidence on (cost-) effectiveness compared with high-intensity psychological therapy alone, as well as with matched care, is required