Outcomes in Living Liver Donor “Heroes” After the Spotlight Fades

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149256/1/lt25459_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149256/2/lt25459.pd

The impact of 120 minutes of match-play on recovery and subsequent match performance:a case report in professional soccer players

The influence of a match including extra-time (ET) on subsequent 90 min match performance and recovery has not been investigated. Four professional soccer players played in three competitive matches in a 7-day period: matches one (MD1) and three (MD3) lasted 90 min and match 2 (MD2) lasted 120 min (i.e., included ET). Physical (total and high-intensity (HI) distance covered, accelerations and decelerations, and mechanical load) and technical performances (pass and dribble accuracy) were analyzed throughout match-play. Subjective measures of recovery and countermovement jump (CMJ) height were made 36–42 h post-match. Post-MD2, there were very or most likely harmful effects of ET on CMJ height (−6 ± 9%), muscle soreness (+18 ± 12%), and fatigue (+27 ± 4%) scores, and overall wellness score (−13 ± 5%) compared to post-MD1. Furthermore, there were very likely harmful effects on muscle soreness (+13 ± 14%), wellness scores (−8 ± 10%), and CMJ height (−6 ± 9%) post-MD3 vs. post-MD1. There was a possibly harmful effect of ET on HI distance covered during MD3, along with reductions in pass (−9.3%) and dribble (−12.4%) accuracy. An ET match negatively impacted recovery 36 h post-match. Furthermore, in some players, indices of performance in a 90 min match played 64 h following ET were compromised, with subsequent recovery also adversely affected

QuakeMigrate: a Modular, Open-Source Python Package for Automatic Earthquake Detection and Location

Detecting and locating microearthquakes from continuous waveform records is the fundamental step in microseismic processing. Dense local networks and arrays have introduced the possibility to detect large numbers of far weaker events, but when viewed on seismic records from individual stations their waveforms are often obscured by noise. Furthermore, areas of interest for microseismic monitoring often feature extremely high event rates, highlighting the limitations of traditional techniques based on phase picking and association. In order to maximise the new insights gained, we require fully automated techniques which can exploit modern recordings to produce highly complete earthquake catalogues containing few artefacts. QuakeMigrate is a new modular, open-source Python package providing a framework to efficiently, automatically and robustly detect and locate microseismicity. The user inputs continuous seismic data, a velocity model or pre-calculated look-up table and list of station locations. Instead of reducing the raw waveforms to discrete time picks, they are transformed (by amplitude, frequency and/or polarisation analysis) to continuous functions representing the probability of a particular phase arrival through time. These ‘onset functions’ from stations across the network are then migrated according to a travel-time look-up table and stacked to perform a grid-search for coherent sources of energy in the subsurface. This enables detection of earthquakes at close to or below the signal-to-noise ratio at individual stations, and implicitly associates phase arrivals even at very small inter-event times. We demonstrate the flexibility and power of this approach with examples of basal icequakes detected at the Rutford Ice Stream, Antarctica, dike- and caldera-collapse induced seismicity at Bárðarbunga central volcano, Iceland, and the aftershock sequence from a M5 earthquake at Mt. Kinabalu, northern Borneo. The modular nature of the workflow and wide range of automatic plotting options makes parameter choice straightforward, and robust event location uncertainty statistics facilitate filtering to produce a robust catalogue. QuakeMigrate also outputs phase picks and local magnitude estimates, with an architecture designed to promote further community-driven extension in future

Intense seismicity during the 2014–15 Bárðarbunga-Holuhraun rifting event, Iceland, reveals the nature of dike-induced earthquakes and caldera collapse mechanisms

Over two weeks in August 2014 magma propagated 48km laterally from Bárðarbunga volcano before erupting at Holuhraun for 6 months, accompanied by collapse of the caldera. A dense seismic network recorded over 47,000 earthquakes before, during and after the rifting event. More than 30,000 earthquakes delineate the segmented dike intrusion. Earthquake source mechanisms show exclusively strike-slip faulting, occurring near the base of the dike along pre-existing weaknesses aligned with the rift fabric, while the dike widened largely aseismically. The slip-sense of faulting is controlled by the orientation of the dike relative to the local rift fabric, demonstrated by an abrupt change from right- to left-lateral faulting as the dike turns to propagate from an easterly to a northerly direction. Approximately 4,000 earthquakes associated with the caldera collapse delineate an inner caldera fault zone, with good correlation to geodetic observations. Caldera subsidence was largely aseismic, with seismicity accounting for 10% or less of the geodetic moment. Approximately 90% of the seismic moment release occurred on the northern rim, suggesting an asymmetric collapse. Well-constrained focal mechanisms reveal sub-vertical arrays of normal faults, with fault planes dipping inward at 60 9 , along both the north and south caldera margins. These steep normal faults strike sub-parallel to the caldera rims, with slip vectors pointing towards the center of subsidence. The maximum depth of seismicity defines the base of the seismogenic crust under Bárðarbunga as 6km b.s.l., in broad agreement with constraints from geodesy and geobarometry for the minimum depth to the melt storage region

Seismicity of the Askja and Bárðarbunga volcanic systems of Iceland, 2009–2015,

A large seismic network deployed in the Icelandic highlands recorded >100,000 earthquakes from 2009 to 2015. We develop a local magnitude scale, appropriate for use in central Iceland, which is similar to the scale used by the Iceland Meteorological Office. Using this large catalogue of earthquakes, we analyze the spatial and temporal changes in seismicity rates and b-values. In microearthquakes recorded from the usually ductile lower crust we find that b-values are high, reflecting the presence of high thermal gradients and low stresses driving seismicity associated with the movement of melt. In contrast, b-values in the upper crust are variable. Low b-values, indicative of a high stress environment, are observed during seismic swarms such as those around Mt. Herðubreið and around Bárðarbunga caldera. A persistently seismically active area around a geothermal area within Askja caldera has a b-value around 1 but has a strong annual cycle of seismicity. We attribute the annual cycle to varying load from the snow cover modulating the seismicity. Seismicity driven by the intrusion of a large dyke has a b-value well above 1, driven by the high pore fluid pressures and thermal gradients around the dyke

Evolution of a lateral dike intrusion revealed by relatively-relocated dike-induced earthquakes: the 2014-15 Bárðarbunga-Holuhraun rifting event, Iceland

Understanding dikes is vital as they serve both as bodies that build the crust and as conduits that feed eruptions, and must be monitored to evaluate volcanic hazard. During the 2014–15 Bárðarbunga rifting event, Iceland, intense seismicity accompanied the intrusion of a ∼50 km lateral dike which culminated in a 6 month long eruption. We here present relocations of earthquakes induced by the lateral dike intrusion, using cross-correlated, sub-sample relative travel times. The ∼100 m spatial resolution achieved reveals the complexity of the dike propagation pathway and dynamics (jerky, segmented), and allows us to address the precise relationship between the dike and seismicity, with direct implications for hazard monitoring. The spatio-temporal characteristics of the induced seismicity can be directly linked in the first instance to propagation of the tip and opening of the dike, and following this – after dike opening – indicate a relationship with magma pressure changes (i.e. dike inflation/deflation), followed by a general ‘post-opening’ decay. Seismicity occurs only at the base of the dike, where dike-imposed stresses – combined with the background tectonic stress (from regional extension over >200 yr since last rifting) – are sufficient to induce failure of pre-existing weaknesses in the crust, while the greatest opening is at shallower depths. Emplacement oblique to the spreading ridge resulted in left-lateral shear motion along the distal dike section (studied here), and a prevalence of left-lateral shear failure. Fault plane strikes are predominately independent of the orientation of lineations delineated by the hypocenters, indicating that they are controlled by the underlying host rock fabric. This high-resolution study provides unprecedented opportunity for comparison with both geodetic and field (frozen dike) observations, and development and consolidation of analytical and analogue models, with implications for rifting processes and real-time monitoring of magma intrusion