A multi-hazard risk model with cascading failure pathways for the Dawlish (UK) railway using historical and contemporary data

The failure of the vital economic railway link between London and the southwest of the United Kingdom in the 2014 storm chain incurred up to £1.2bn of economic losses. This incident highlighted the urgent need to understand the cascading nature of multi hazards involved in storm damage. This study focuses on the Dawlish railway where a seawall breach caused two months of railway closure in 2014. We used historical and contemporary data of severe weather damage and used failure analysis to develop a multi-hazard risk model for the railway. Twenty-nine damage events caused significant line closure in the period 1846–2014. For each event, hazards were identified, the sequence of failures were deconstructed, and a flowchart for each event was formulated showing the interrelationship of multiple hazards and their potential to cascade. The most frequent damage mechanisms were identified: (I) landslide, (II) direct ballast washout, and (III) masonry damage. We developed a risk model for the railway which has five layers in the top-down order of: (a) root cause (storm); (b) force generation (debris impact, wave impact, overtopping, excess pore pressure, wind impacts); (c) common cause failure (slope instability, rail flooding, coping and parapet damage, foundation failure and masonry damage); (d) cascading failure (landslide, ballast washout, upper masonry seawall failure, loss of infill material), and (e) network failure forcing service suspension. We identified five separate failure pathways and damage mechanisms by analysing these 29 major events

Extratropical cyclone damage to the seawall in Dawlish, UK: eyewitness accounts, sea level analysis and numerical modelling

The February 2014 extratropical cyclonic storm chain, which impacted the English Channel (UK) and Dawlish in particular, caused significant damage to the main railway connecting the south-west region to the rest of the UK. The incident caused the line to be closed for two months, £50 million of damage and an estimated £1.2bn of economic loss. In this study, we collate eyewitness accounts, analyse sea level data and conduct numerical modelling in order to decipher the destructive forces of the storm. Our analysis reveals that the disaster management of the event was successful and efficient with immediate actions taken to save lives and property before and during the storm. Wave buoy analysis showed that a complex triple peak sea state with periods at 4–8, 8–12 and 20–25 s was present, while tide gauge records indicated that significant surge of up to 0.8 m and wave components of up to 1.5 m amplitude combined as likely contributing factors in the event. Significant impulsive wave force of up to 286 KN was the most likely initiating cause of the damage. Reflections off the vertical wall caused constructive interference of the wave amplitudes that led to increased wave height and significant overtopping of up to 16.1 m3/s/m (per metre width of wall). With this information and our engineering judgement, we conclude that the most probable sequence of multi-hazard cascading failure during this incident was: wave impact force leading to masonry failure, loss of infill and failure of the structure following successive tides

Developing the Principles of Parental Mental Health in the Neonatal Intensive Care Unit (NICU)

Background: Hospitalization of infants in the neonatal intensive care unit (NICU) may disrupt the proper interaction with infants and lead to anxiety and depression, while adversely affecting the role of families. Therefore, it is necessary for healthcare teams to be familiar with the principles of parental mental health in the NICU. The present study aimed to codify the principles of parental mental health in the NICU. Methods: This study was conducted with a triangulation methodology in two steps. In the first step, the principles of mental health care for parents in the NICU were compiled and translated. In the second step, the principles were edited using the Delphi method based on the opinion of experts (physicians, faculty members, and health policymakers). Final principles of parental mental health in the NICU were codified. Results: In total, four general principles of holistic care, relationship with parents in the NICU, special care for establishing communication with families in the NICU, and principles of infants and family care were obtained. Conclusion: Since healthcare teams may not be familiar with the principles of parental mental health in the NICU, the results of the present study could lay the groundwork for promoting the knowledge of healthcare team members in interaction with parents

The effect of posture in premature infants on the arterial oxygen saturation, fraction of inspired oxygen and abdominal distension

Background: Putting infants in a posture that reduces oxygen requirement and the complications of the continuous positive airway pressure method is very important. This study aimed at examining the effect of the posture on the arterial oxygen saturation, fraction of inspired oxygen (FIO2) and abdominal distension in premature infants with the respiratory distress syndrome under nasal continuous positive airway pressure. Materials and Methods: In this clinical trial study, 41 premature infants were selected by the simple random sampling and one-group before-after design. The amounts of arterial oxygen saturation, FIO2 and abdominal distension in supine and prone positions were recorded in a data-collection form. Results: There was a significant difference between the mean FIO2 and between the mean abdominal circumference in the prone and supine positions (P=0.022, P<0.001, respectively). There was no significant difference in the mean of arterial oxygen saturation between the two positions (P=0.749). Conclusion: According to the results of the present study, the neonates’ abdominal distension and FIO2 decreased in the prone position. Thus, this supportive, free of charge and effective method can be recommended for these neonates

Multi-level emulation of tsunami simulations over Cilacap, South Java, Indonesia

Carrying out a Probabilistic Tsunami Hazard Assessment (PTHA) requires a large number of simulations done at a high resolution. Statistical emulation builds a surrogate to replace the simulator and thus reduces computational costs when propagating uncertainties from the earthquake sources to the tsunami inundations. To reduce further these costs, we propose here to build emulators that exploit multiple levels of resolution and a sequential design of computer experiments. By running a few tsunami simulations at high resolution and many more simulations at lower resolutions we are able to provide realistic assessments whereas, for the same budget, using only the high resolution tsunami simulations do not provide a satisfactory outcome. As a result, PTHA can be considered with higher precision using the highest spatial resolutions, and for impacts over larger regions. We provide an illustration to the city of Cilacap in Indonesia that demonstrates the benefit of our approach.</p

Multi-level emulation of tsunami simulations over Cilacap, South Java, Indonesia

Carrying out a Probabilistic Tsunami Hazard Assessment (PTHA) requires a large number of simulations done at a high resolution. Statistical emulation builds a surrogate to replace the simulator and thus reduces computational costs when propagating uncertainties from the earthquake sources to the tsunami inundations. To reduce further these costs, we propose here to build emulators that exploit multiple levels of resolution and a sequential design of computer experiments. By running a few tsunami simulations at high resolution and many more simulations at lower resolutions we are able to provide realistic assessments whereas, for the same budget, using only the high resolution tsunami simulations do not provide a satisfactory outcome. As a result, PTHA can be considered with higher precision using the highest spatial resolutions, and for impacts over larger regions. We provide an illustration to the city of Cilacap in Indonesia that demonstrates the benefit of our approach

Application of dense offshore tsunami observations from Ocean Bottom Pressure Gauges (OBPGs) for tsunami research and early warnings

We introduce a new data source of dense deep-ocean tsunami records 7 from Ocean Bottom Pressure Gauges (OBPGs) which are attached to Ocean Bottom 8 Seismometers (OBS) and apply them for far-field and near-field tsunami warnings. 9 Tsunami observations from OBPGs are new sources of deep-ocean tsunami 10 observations which, for the first time, provide dense tsunami data with spacing 11 intervals in the range of 10–50 km. Such dense data are of importance for tsunami 12 research and warnings and are capable of providing new insights into tsunami 13 characteristics. Here, we present a standard procedure for the processing of the 14 OBPG data and extraction of tsunami signals out of these high-frequency data. 15 Then, the procedure is applied to two tsunamis of 15 July 2009 Mw 7.8 Dusky 16 Sound (offshore New Zealand) and 28 October 2012 Mw 7.8 Haida Gwaii (offshore 17 Canada). We successfully extracted 30 and 57 OBPG data for the two aforesaid 18 tsunamis, respectively. Numerical modeling of tsunami was performed for both 19 tsunamis in order to compare the modeling results with observation and to use the 20 modeling results for the calibration of some of the OBPG data. We successfully 21 employed the OBPG data of the 2012 Haida Gwaii tsunami for tsunami forecast by 22 applying a data assimilation technique. Our results, including two case studies, 23 demonstrate the high potential of OBPG data for contribution to tsunami research 24 and warnings. The procedure developed in this study can be readily applied for the 2526 extraction of tsunami signals from OBPG data

Possible dual earthquake-landslide source of the 13 November 2016 Kaikoura, New Zealand tsunami

A complicated earthquake (Mw 7.8) in terms of rupture mechanism occurred in the NE coast of South Island, New Zealand on 13 November 2016 (UTC) in a complex tectonic setting comprising a transition strike-slip zone between two subduction zones. The earthquake generated a small tsunami with zero-to-crest amplitude of 257 cm at the near-field tide gauge station of Kaikoura. Spectral analysis of the tsunami observations showed dual peaks at 3.6–5.7 and 5.7–56 min, which we attribute to the potential landslide and earthquake sources of the tsunami, respectively. Tsunami simulations showed that a source model with slip on an offshore plate-interface fault reproduces the near-field tsunami observation in terms of amplitude but fails in terms of tsunami period. On the other hand, a source model without offshore slip fails to reproduce the first peak, but the later phases are reproduced well in terms of both amplitude and period. It can be inferred that an offshore source is necessary to be involved, but it needs to be smaller in size than the plate-interface, which most likely points to a confined submarine landslide source; consistent with the dual-peak tsunami spectrum. We estimated the dimension of the potential submarine landslide at 8–10 km.This research was funded by Brunel Research Initiative & Enterprise Fund 2017/18 (BUL BRIEF) at the Brunel University London to the lead author (MH)