First motions from seismic sources near a free surface

The radiation patterns of first motions are calculated for the sudden occurrence of an arbitrarily oriented fault (dislocation) at the surface of a half space; the dislocation in the fault plane is also arbitrarily oriented and is assumed to occur over a very small area of the fault plane. Initially the source is considered at a finite depth and the solution is obtained by allowing the depth to tend to zero. In general the results show a surprising directionality for the radiation of SV. In the focal plane projection the first motions of P and SH for a strike-slip fault show the familiar four-lobed radiation patterns. The first motions of SV show some reversals in polarity with angular distance from the source. The first motions for all components of motion for a dip-slip fault have characteristics governed strongly by the presence of the free surface, and hence differ markedly from the usual radiation patterns for a deeply imbedded source

Race and Transit Investment in DeKalb County, Georgia

MCRP Applied Research Paper, Class of 2021This paper aims to dissect intra-county neighborhood-level attitudes to transit in DeKalb County, Georgia, and the way in which they have fallen along racial and class lines during the five decades that the county has funded MARTA. This paper explores how these attitudes and their expression in neighborhood organizing have affected where transit dollars have been spent, where they have been wasted, and where they have not gone despite general support for them

Undertaking Doctoral Research with Children and Young People with Life-limiting or Life-threatening Conditions

Doctoral level research can contribute to the evidence base, particularly in under‐researched areas and numerically small fields such as children and young people's palliative care. It is acknowledged that much of what we currently do in children's and young people's palliative care is eminence‐based, rather than evidence‐based (Together for Short Lives, 2018). Whilst sharing experience and wisdom was valuable, particularly when the specialty was in its infancy, it is important now to develop an evidence base to ensure that children, young people and their families receive the highest standard of care. This requires fostering the development of a research culture, including trained clinical and non‐clinical researchers, who will pursue a penetrating and rigorous research agenda (Beecham et al., 2016)

Development of a research-based classification of approaches to paediatric palliative medicine service provision within children's and young adults' hospices: A mixed methods study.

BACKGROUND: Globally, pioneers in children's palliative care influenced this speciality's development through individual initiatives leading to diverse models of care. Children's and young adults' hospices have now been established around the world. However, service provision varies widely leading to inequities both within countries and internationally. AIM: To describe and classify existing approaches to paediatric palliative medicine in children's and young adults' hospices across the UK. DESIGN: A mixed methods study conducted by telephone interview. SETTING/PARTICIPANTS: Thirty-one leaders of children's hospice care, representing 28 services, 66% of UK children's and young adults' hospice organisations. RESULTS: A geographic-specialist classification was developed through integration of findings, enabling hospices to be classified as Regional specialist, Regional non-specialist, Local specialist and Local non-specialist. Both qualitative and quantitative data demonstrated diversity and inequity in paediatric palliative medicine provision. Of 159 doctors (63.5% of whom were general practitioners) working in participating hospices only 27.5% had specialist training in paediatric palliative medicine. The majority of participating hospices (67.9%) did not have involvement from a paediatric palliative medicine consultant. CONCLUSIONS: Internationally, the integration of specialist children's palliative care teams with existing services is a current challenge. Despite differing approaches to children's palliative care world-wide, models of care which facilitate integration of specialist children's palliative care could benefit a range of countries and contexts. The geographic-specialist classification could be used to inform recommendations for a networked approach to paediatric palliative medicine within children's and young adults' hospices to promote equity for children with life-limiting and life-threatening conditions

Housing for the cost burdened: a step toward a just society

Affordable housing is one of Atlanta, Georgia’s most pressing, pervasive, and persistent urban planning crises. Additionally, the advent of the ongoing COVID-19 pandemic has exacerbated the preexisting affordable housing issues across housing security, demographics, the supply and demand of affordable housing policy, and the health of low-income housing occupants. This report aims to address these issues, as they currently persist in Atlanta, and offer recommendations and considerations for their solutions. This document consists of four sections: Affordable Housing Finance in the City of Atlanta, Wealth Divide and Housing, Homelessness, Health & Hazards. A case study of Atlanta’s Healthy Hotel Project, and the Nexus of Housing, Transit, and Jobs. This report was created by graduate students in the master’s in City and Regional Planning Program (MCRP) at the Georgia Institute of Technology in collaboration with multiple local stakeholders. Though this report will not solve the affordable housing issue in the city of Atlanta, it will address the current conditions and numerous challenges associated with affordable housing in Atlanta and will offer a pointed recommendation to create a path toward solutions for these wicked problems

Convective instability of 3-D fluid-saturated geological fault zones heated from below

We conduct a theoretical analysis to investigate the convective instability of 3-D fluid-saturated geological fault zones when they are heated uniformly from below. In particular, we have derived exact analytical solutions for the critical Rayleigh numbers of different convective flow structures. Using these critical Rayleigh numbers, three interesting convective flow structures have been identified in a geological fault zone system. It has been recognized that the critical Rayleigh numbers of the system have a minimum value only for the fault zone of infinite length, in which the corresponding convective flow structure is a 2-D slender-circle flow. However, if the length of the fault zone is finite, the convective flow in the system must be 3-D. Even if the length of the fault zone is infinite, since the minimum critical Rayleigh number for the 2-D slender-circle flow structure is so close to that for the 3-D convective flow structure, the system may have almost the same chance to pick up the 3-D convective flow structures. Also, because the convection modes are so close for the 3-D convective flow structures, the convective flow may evolve into the 3-D finger-like structures, especially for the case of the fault thickness to height ratio approaching zero. This understanding demonstrates the beautiful aspects of the present analytical solution for the convective instability of 3-D geological fault zones, because the present analytical solution is valid for any value of the ratio of the fault height to thickness. Using the present analytical solution, the conditions, under which different convective flow structures may take place, can be easily determined

Hydrothermally-induced melt lens cooling and segmentation along the axis of fast- and intermediate-spreading centers

Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 38 (2011): L14307, doi:10.1029/2011GL047798.The heat output and thermal regime of fast and intermediate spreading centers are strongly controlled by boundary layer processes between the hydrothermal system and the underlying crustal magma chamber (AMC), which remain to be fully understood. Here, we model the interactions between a shallow two-dimensional cellular hydrothermal system at temperatures <700°C, and a deeper AMC at temperatures up to 1200°C. We show that hydrothermal cooling can freeze the AMC in years to decades, unless melt injections occur on commensurate timescales. Moreover, the differential cooling between upflow and downflow zones can segment the AMC into mush and melt regions that alternate on sub-kilometric length scales. These predictions are consistent with along-axis variations in AMC roof depth observed in ophiolites and oceanic settings. In this respect, fine-scale geophysical investigations of the structure of AMCs may help constrain hydrothermal recharge locations associated with active hydrothermal sites