Local earthquake tomography of Scotland

Scotland is a relatively aseismic region for the use of local earthquake tomography, but 40 yr of earthquakes recorded by a good and growing network make it possible. A careful selection is made from the earthquakes located by the British Geological Survey (BGS) over the last four decades to provide a data set maximising arrival time accuracy and ray path coverage of Scotland. A large number of 1-D velocity models with different layer geometries are considered and differentiated by employing quarry blasts as ground-truth events. Then, SIMULPS14 is used to produce a robust 3-D tomographic P-wave velocity model for Scotland. In areas of high resolution the model shows good agreement with previously published interpretations of seismic refraction and reflection experiments. However, the model shows relatively little lateral variation in seismic velocity except at shallow depths, where sedimentary basins such as the Midland Valley are apparent. At greater depths, higher velocities in the northwest parts of the model suggest that the thickness of crust increases towards the south and east. This observation is also in agreement with previous studies. Quarry blasts used as ground truth events and relocated with the preferred 3-D model are shown to be markedly more accurate than when located with the existing BGS 1-D velocity model

Effect of a bereavement support group on female adolescents’ psychological health: a randomised controlled trial in South Africa

Background Bereavement increases children’s risk for psychological disorders, highlighting the need for effective interventions, especially in areas where orphanhood is common. We aimed to assess the effects of an eight-session support group intervention on the psychological health of bereaved female adolescents in South Africa. Methods This randomised controlled trial enrolled female adolescents at 11 schools in three peri-urban towns of Free State province, South Africa. 453 bereaved ninth-grade students aged 13–17 years who had expressed interest in taking part in the group were randomly assigned (1:1) to receive the intervention or to be waitlisted for programme enrolment after the study period and serve as the control group. The intervention, Abangane (“friends” in isiZulu), is a locally derived, curriculum-based support group focused on coping with loss incorporating indigenous stories and cognitive behavioural therapy components. Weekly group sessions were facilitated by trained social workers or social auxiliary workers from a local non-profit organisation. The primary outcomes included indicators of grief and depression as reported by adolescents and behavioural problems reported by their caregivers. Grief was measured with three scales: the grief subscale of the Core Bereavement Items to assess normative grief; and the Intrusive Grief Thoughts Scale and the Inventory of Complicated Grief–Revised for Children to assess maladaptive grief symptoms in the past 4 weeks. Depression symptoms in the past 7 days were measured with the Center for Epidemiological Studies–Depression Scale for Children. Caregivers completed the Brief Problem Monitor-Parent Form to report on adolescent’s behaviour in the previous 4 weeks. Analysis was intention to treat. This study is registered with ClinicalTrials.gov, number NCT02368808. Findings Between Sept 30, 2014, and Feb 5, 2015, eligible female participants were identified, of whom 226 were assigned to the intervention, Abangane, and 227 were assigned to the waitlisted control group. Analysis included 382 adolescents who completed both surveys (193 participants assigned to Abangane and 189 assigned to waitlist). At follow up, the intervention group had significantly lower scores for primary outcomes, including intrusive grief (p=0·000, Cohen’s d=–0·21), complicated grief (p=0·015, d=–0·14), and depression (p=0·009, d=–0·21) relative to the waitlisted group, while core bereavement scores were similar between groups (p=0·269). Caregivers in the intervention group reported lower levels of behavioural problems among adolescents (p=0·017, d=–0·31). Interpretation Short-term, structured, theory-based support groups with contextually relevant content show promise in mitigating psychological and behavioural problems among bereaved adolescents. Abangane is replicable in resource limited settings, using freely available curriculum materials, existing programme structures, and appropriately trained personnel to implement it

Extending local magnitude ML to short distances

Local magnitudes calculated at stations less than 10 km from earthquakes in the British Isles are up to one unit of magnitude higher than local magnitudes calculated at more distant stations. This causes a considerable overestimate of the event magnitude, particularly for small events, which are only recorded at short distances. Data from Central Italy and Norway show that the same problem also occurs in other regions, suggesting that this is a more general issue for local magnitude scales. We investigate the addition of a new exponential term to the general form of the local magnitude scale. This corrects for the higher-than-expected amplitudes at short hypocentral distances. We find that the addition of this new term improves magnitude estimates in the three studied regions and magnitudes at short distances are no longer overestimated. This allows the use of a single scale that can be used at all distances, with a smooth transition between short and long distances. For the UK, the amended scale is M L =log(amp) +1.11log(r)+0.00189r−1.16e −0.2r −2.09 ML =log⁡(amp) +1.11log⁡(r)+0.00189r−1.16e−0.2r−2.09 and this is the scale now used by the British Geological Survey

Environmental Exposure to Emissions from Petrochemical Sites and Lung Cancer: The Lower Mississippi Interagency Cancer Study

To investigate potential links between environmental exposure to petrochemical plant emissions and lung cancer, a population-based case-control study (LMRICS) was conducted in eleven Louisiana parishes bordering the Mississippi River. Cases and age, gender, and race-matched controls were interviewed regarding potential risk factors. Residential history was geocoded to provide indices of long-term proximity to industrial sites. Cases were more likely to have lived near a petrochemical site. Models adjusted for other risk factors, however, showed small or no association with lung cancer (odds ratio for residence within a half-mile of a site = 1.10, 95% confidence interval 0.58–2.08). While associations were strongest for exposures exceeding 15 years, none approached statistical significance and there was no clear dose-response across exposure duration, distance categories, or when sites were grouped according to carcinogenicity rating of chemical releases. Residential proximity to petrochemical plants along the lower Mississippi thus showed no significant association with lung cancer

Pathways to sexual health communication between adolescent girls and their female caregivers participating in a structured HIV prevention intervention in South Africa

RATIONALE : Interventions that promote sexual health communication between adolescents and their parents or other primary caregivers are an important tool for reducing female adolescents’ behavioral risk. Understanding the mechanisms by which interventions effectively foster communication can inform future programs. OBJECTIVE : An initial evaluation of Let's Talk, a structured, family-centered HIV prevention intervention for vulnerable adolescents in South Africa, found an increase in caregiver-adolescent sexual communication. This analysis expands upon initial findings to explore the role of parental knowledge, the quality of the parentadolescent relationship, and the mental health of both parties on caregiver-adolescent sexual health communication. METHOD : Using mixed methods data collected in 2015 and 2016, structural equation modeling of differenced preand postintervention survey data from 64 female Let's Talk participants ages 13–17 and their caregivers was used to explore the pathway to increased frequency of caregiver-adolescent sexual health communication. Focus group discussions (FGDs) were held with intervention participants (n = 25) and facilitators (n = 6). RESULTS : The path analysis indicates that caregivers' mental health indirectly affected caregiver-adolescent relationship quality, and adolescents' mental health exerted a direct effect. Relationship quality, in turn, directly affected the level of parental sexual communication reported by the adolescent. FGDs suggested that cultural norms inhibit frank discussions between caregivers and adolescents about sexual health, but that thoughtfully designed interventions such as Let's Talk can mitigate this barrier. Qualitative findings also echoed quantitative findings about the role of caregiver-adolescent relationship quality and mental health on communication frequency and highlighted the importance of enhancing participants' technical knowledge and particularly their skills related to expression, listening, and anger management to help enable sensitive conversations. CONCLUSIONS : Findings overall suggest that a holistic intervention approach emphasizing caregiver-adolescent relationship development and designed to support the mental health of both parties may hold significant promise for enhancing sexual health communication.The President's Emergency Plan for AIDS Relief (PEPFAR) through United States Agency for International Development (USAID) Southern Africa under the terms of Cooperative Agreement No. AID-674-A-12-00002.http://www.elsevier.com/locate/socscimedam2021Psycholog

Seismicity induced by longwall coal mining at the Thoresby Colliery, Nottinghamshire, U.K.

The United Kingdom has a long history of deep coal mining, and numerous cases of mining-induced seismicity have been recorded over the past 50 yr. In this study, we examine seismicity induced by longwall mining at one of the United Kingdom’s last deep coal mines, the Thoresby Colliery, Nottinghamshire. After public reports of felt seismicity in late 2013 a local seismic monitoring network was installed at this site, which provided monitoring from February to October 2014. This array recorded 305 seismic events, which form the basis of our analysis. Event locations were found to closely track the position of the mining face within the Deep Soft Seam, with most events occurring up to 300 m ahead of the face position. This indicates that the seismicity is being directly induced by the mining, as opposed to being caused by activation of pre-existing tectonic features by stress transfer. However, we do not observe correlation between the rate of excavation and the rate of seismicity, and only a small portion of the overall deformation is being released as seismic energy. Event magnitudes do not follow the expected Gutenberg–Richter distribution. Instead, the observed magnitude distributions can be reproduced if a truncated power-law distribution is used to simulate the rupture areas. The best-fitting maximum rupture areas correspond to the distances between the Deep Soft Seam and the seams that over- and underlie it, which have both previously been excavated. Our inference is that the presence of a rubble-filled void (or goaf) where these seams have been removed is preventing the growth of larger rupture areas. Source mechanism analysis reveals that most events consist of dip-slip motion along near-vertical planes that strike parallel to the orientation of the mining face. These mechanisms are consistent with the expected deformation that would occur as a longwall panel advances, with the under- and overburdens moving upwards and downwards respectively to fill the void created by mining. This further reinforces our conclusion that the events are directly induced by the mining process. Similar mechanisms have been observed during longwall mining at other sites