Explore the vast range of titles available.

The 14 August 2021 Haiti earthquake mainly portrayed reverse motion to the east near L’Asile town and left‐lateral strike‐slip motion to the west near Camp‐Perrin town. To map the rupture and infer its segmentation, we conducted the first post‐seismic field reconnaissance along the left‐lateral strike‐slip Enriquillo fault from L’Asile to Macaya mountain. We identified 98 linear, minor cracks that are not representative of primary fault surface rupture. Analyzing the topographic slope distribution, we detected that the cracks were often located in areas that are prone to topographic instability. About 60% of the cracks are located in Quaternary alluvium and Middle‐Miocene continental marls, indicating a preference for soft sediments. The rivers also have an impact, as crack lengths and openings negatively correlate with their distance to neighboring rivers. In addition, the earthquake occurred in a rainy region with up to 2,479.34 mm of rainfall in 2021, increasing soil instability. Above all, we found a contrast and asymmetry between the eastern and the western parts of the rupture. By dividing the 60‐km long rupture into two equal parts, we observed 57 cracks to the west against 41 to the east. The longest and the widest cracks are to the west. Analyzing their orientation, the cracks mainly oriented as left‐lateral strike‐slip faults to the west and mainly thrusts to the east. This configuration appears to be influenced by the slip pattern of the 2021 Haiti earthquake and consistent with the regional stress field. Key Points Alongside geology, topography, and hydroclimate, tectonics is the biggest factor for crack generation during the 14 August 2021, Mw 7.2 Haiti earthquake Thrust and sinistral strike‐slip cracks partition similarly to the earthquake slip pattern and to the oblique‐convergence margin

A large proportion of right-hemisphere stroke patients show hemispatial neglect—a neurological deficit of perception, attention, representation, and/or performing actions within their left-sided space 1 , inducing many functional debilitating effects on everyday life, and responsible for poor functional recovery and ability to benefit from treatment 2 . The frequent parietal locus of the lesion producing neglect reflects the impairment of coordinate transformation used by the nervous system to represent extrapersonal space. Given that adaptation to a visual distortion can provide an efficient way to stimulate neural structures responsible for the transformation of sensorimotor coordinates, the aim of our study was to investigate the effect of prism adaptation on various neglect symptoms, including the pathological shift of the subjective midline to the right. All patients exposed to the optical shift of the visual field to the right were improved on their manual body-midline demonstration and on classical neuropsychological tests. Unlike other physiological manipulations used to improve neglect, this improvement lasted for at least two hours after prism removal and thus could be useful in rehabilitation programmes. The positive effect found for both sensorimotor and more cognitive spatial functions suggests that they share or depend on a common level of space representation linked to multisensory integration.

In the frame of a Belgo-Haitian cooperation project (PIC 2012–2016), a study of the local seismic hazard was performed in Fond Parisien, an area located on the foothills of the “Massif de la Selle”, along the easternmost portion of the Enriquillo Plantain Garden Fault (EPGF). The H/V Spectral Ratio (HVSR) technique was applied to study the resonance frequency of the target areas and the azimuth of the wave field. The amplification factors were estimated using Standard Spectral Ratios obtained from earthquakes recorded by a temporary seismic network. Using the Multichannel Analysis of Surface Waves method, the seismic properties of the shallow layers were investigated. Then, the results were compared to local Electrical Resistivity Tomography data. These results highlight, in the central part of Fond Parisien, an E-W zone of low velocities ranging from 200 m/s to 450 m/s and low resistivities between 1 Ωm and 150 Ωm, due both to tectonic folding of the rocks and to the presence of sediment filling in the eastern part. The latter is marked, in most of its sites, by resonances at one or more frequencies ranging from 0.7 Hz to 20 Hz. Infiltration and storage of brackish water in the underground layers also contribute to the low resistivity values. With the noise HVSR data, we also evidenced a significant influence of the EPGF on the main orientation of the seismic wavefield as in the vicinity of this fault, the azimuths are parallel to the orientation of the fault. Overall, the results also show greater potential for site effects in the block formed by the sedimentary basin and strong amplification of the seismic ground motion for the sites bordering the basin to the north and west. We interpret the amplification in the north and south-west as probably originating from topographic irregularities locally coupled with sediment deposits, while in the center of the western part, the site effects could be explained by the presence of folds and related weakened and softened rocks. By the integration of several geophysical methods, we could distinguish areas where it is possible to build more safely. These zones are located in the northern part and encompass Quisqueya Park and neighboring areas as well as the village “La Source” in the southern part. In the rest of Fond Parisien, i.e., in the more central and eastern parts, buildings should be erected with caution, taking into account the nearby presence of the EPGF and the influence of fine sediments on the amplification of the seismic motion.

This paper presents the general results in terms of maps, as well as geological and numerical models of a site effect study, that aimed at a better understanding of the ground motion amplification on the Gros-Morne hill, in the southeastern part of Port-au-Prince, Haiti, which might have influenced the 2010 event damage pattern in that area. These maps and models are based on multiple geophysical–seismological survey outputs that are presented, in detail, in Part A of this publication. Those outputs include electrical resistivity tomography sections, P-wave velocity profiles, S-wave logs, estimates of the fundamental resonance frequency for many locations, as well as earthquake recordings at three sites and associated site amplification assessment for the top of the hill. Related results are discussed in Part A with respect to outputs and interpretations that had been published earlier by other research teams for the same site. Our results only partly confirm the strong seismic amplification effects highlighted by some of the previous studies for this hill site, which had been attributed to the influence of local topographic and soil characteristics on seismic ground motion. Here, we focus on the imaging of different site effect components over the entire survey area; we present maps of shear wave velocity variations, of changing fundamental resonance frequencies, and of related estimates of soft soil/rock thickness, of peak spectral amplitudes, and of ambient ground motion polarization. Results have also been compiled within a 3D surface–subsurface model of the hill, which helps visualize the geological characteristics of the area, which are relevant for site effect analyses. From the 3D geomodel, we extracted one 2D geological section along the short-axis of the hill, crossing it near the location of Hotel Montana on top of the hill, which had been destroyed during the earthquake, and has now been rebuilt. This cross-section was used for dynamic numerical modelling of seismic ground motion, and for related site amplification calculation. The numerical results are compared with the site amplification characteristics that had been estimated from the ambient vibration measurements and the earthquake recordings.

After the M = 7.0 Haiti earthquake in 2010, many teams completed seismic risk studies in Port-au-Prince to better understand why this not extraordinarily strong event had induced one of the most severe earthquake disasters in history (at least in the Western World). Most highlighted the low construction quality as the main cause for the disaster, but some also pointed to possible soil and topographic amplification effects, especially in the lower and central parts of Port-au-Prince (e.g., close to the harbor). However, very detailed local studies of such site effects have not been completed yet. A Belgian-Haitian collaboration project was established in order to develop a detailed local seismic hazard study for Gros-Morne hill located in the district of Pétion-Ville, southeast of Port-au-Prince. In order to have a better understanding of the amplification on the Gros-Morne hill, in the southeastern part of Port-au-Prince, site effects were investigated by using near surface geophysical methods. The horizontal to vertical spectral ratio technique was applied to ambient vibrations and earthquake data, and multichannel analysis of surface waves and P-wave refraction tomography calculation were applied to seismic data. Standard spectral ratios were computed for the S-wave windows of the earthquake data recorded by a small temporary seismic network. Electrical resistivity tomography profiles were also performed in order to image the structure of the subsurface and detect the presence of water, if any. The spectral ratio results generally show low to medium (1.5–6) resonance amplitudes at one or several different resonance frequencies (for the same site), between 0.5 and 25 Hz. At most of the investigated sites, the fundamental resonance frequency varies between 7 and 10 Hz. By using the multichannel surface wave analyses of the seismic data, we were able to determine shear wave velocities ranging between 200 and 850 m/s, up to a depth of about 15–20 m. From the refraction analysis, we were able to delineate P-waves velocities of 500 to 1500–2000 m/s at the studied sites. The outputs were locally compared with the resistivity data from the electrical profiles. Thus, the overall data indicate a moderate site effect at Gros-Morne hill, with a great variability in site amplification distribution. Initial estimates of local site effects were made on the basis of those outputs and the earthquake recordings. Our results are finally discussed with respect to outputs and interpretations that had been published earlier for the same site. Those results only partly confirm the strong seismic amplification effects highlighted by previous papers for this hill site, which had been explained by the effects of the local topographic and soil characteristics.

First analyses of landslide distribution and triggering factors are presented for the region affected by the 14 August 2021 earthquake (Mw=7.2) in the Nippes Department, Haiti. Landslide mapping was mainly carried out by comparing pre- and post-event remote imagery (∼0.5–1 m resolution) available on Google Earth Pro® and Sentinel-2 (10 m resolution) satellite images. The first covered about 50 % of the affected region (for post-event imagery and before completion of the map in January 2022), and the latter were selected to cover the entire potentially affected zone. On the basis of the completed landslide inventory, comparisons are made with catalogs compiled by others both for the August 2021 and the January 2010 seismic events, including one open inventory (by the United States Geological Survey) that was also used for further statistical analyses. Additionally, we studied the pre-2021 earthquake slope stability conditions. These comparisons show that the total number of landslides mapped for the 2021 earthquake (7091) is larger than the one recently published by another research team for the same event but slightly smaller than the number of landslides mapped by a third research team. It is also clearly smaller than the one observed by two other research teams for the 2010 earthquake (e.g., 23 567, for the open inventory). However, these apparently fewer landslides triggered in 2021 cover much wider areas of slopes (>80 km2) than those induced by the 2010 event (∼25 km2 – considering the open inventory). A simple statistical analysis indicates that the lower number of 2021 landslides can be explained by the missing detection of the smallest landslides triggered in 2021, partly due to the lower-resolution imagery available for most of the areas affected by the recent earthquake; this is also confirmed by an inventory completeness analysis based on size–frequency statistics. The much larger total area of landslides triggered in 2021, compared to the 2010 earthquake, can be related to different physical reasons: (a) the larger earthquake magnitude in 2021, (b) the more central location of the fault segment that ruptured in 2021 with respect to coastal zones, (c) and possible climatic preconditioning of slope instability in the 2021 affected area. These observations are supported by (1) a new pre-2021 earthquake landslide map; (2) rainfall distribution maps presented for different periods (including October 2016 – when Hurricane Matthew had crossed the western part of Haiti), covering both the 2010 and 2021 affected zones; and (3) shaking intensity prediction maps.

The Haiti region – bounded by two strike-slip faults expressed both onshore and offshore – offers a unique opportunity for an amphibious drilling project. The east–west (EW)-striking, left lateral strike-slip Oriente–Septentrional fault zone and Enriquillo–Plantain Garden fault zone bounding Haiti have similar slip rates and also define the northern and southern boundaries of the Gonâve Microplate. However, it remains unclear how these fault systems terminate at the eastern boundary of that microplate. From a plate tectonic perspective, the Enriquillo–Plantain Garden fault zone can be expected to act as an inactive fracture zone bounding the Cayman spreading system, but, surprisingly, this fault has been quite active during the last 500 years. Overall, little is understood in terms of past and present seismic and tsunami hazards along the Oriente–Septentrional fault zone and Enriquillo–Plantain Garden fault zone, their relative ages, maturity, lithology, and evolution – not even the origin of fluids escaping through the crust is known. Given these unknowns, the Haiti-Drill workshop was held in May 2019 to further develop an amphibious drilling project in the Haiti region on the basis of preproposals submitted in 2015 and their reviews. The workshop aimed to complete the following four tasks: (1) identify significant research questions; (2) discuss potential drilling scenarios and sites; (3) identify data, analyses, additional experts, and surveys needed; and (4) produce timelines for developing a full proposal. Two key scientific goals have been set, namely to understand the nature of young fault zones and the evolution of transpressional boundaries. Given these goals, drilling targets were then rationalized, creating a focus point for research and/or survey needs prior to drilling. Our most recent efforts are to find collaborators, analyze existing data, and to obtain sources of funding for the survey work that is needed.

Prism adaptation (PA) alleviates some neglect symptoms, however, the mechanisms underlying these effects are unclear. One brain area that may be important in generating these beneficial effects is the superior parietal lobe (SPL), a region not typically damaged in neglect, and known to be important for attention, visuomotor control, and eye movements. We examined the effects of rightward PA on covert attention in CF, a patient with bilateral SPL lesions, compared to a group of controls ( N  = 26) who underwent sham adaptation. In contrast to previous work in neglect, there was no reduction in CF’s leftward disengage deficit, or rightward attentional bias following PA. These results suggest that the SPL plays an important role in generating the beneficial after-effects of prisms on attention.

In this study, 33 patients were randomly assigned to receive desflurane (D) or isoflurane (I) for acoustic neuroma surgery. The time from end of the procedure to spontaneous breathing, extubation, eye-opening, hand-squeezing to command, and ability to state name, birthdate and phone number were recorded. The Steward recovery score was also recorded every five minutes during the first 20 minutes postoperatively and then every 10 to 15 minutes. Groups were similar regarding patient characteristics, depth of anaesthesia, sufentanil total dose, anaesthesia duration (D: 349.1 ±19.1 min; I: 349.2±22.9 min), haemodynamic/respiratory parameters, and surgical conditions (assessed by a bleeding score). The emergence time in the D group was significantly faster than the I group (D: 14.9±2.4 min vs I: 29.2±2.4 min for eye-opening). Full recovery also occurred earlier in the D group (D: 22.1±3.1 min vs I: 37.6±4.0 min, P<0.005 for stating name). Steward recovery scores were also better during the first postoperative hour in the D group (D: 40 min vs I: 90 min, P<0.005 for 100% of patients with Steward score of 6). The results indicate that desflurane is associated with similar operating conditions and faster postoperative recovery following acoustic neuroma surgery. The faster recovery following desflurane may be desirable after long surgical procedures, enabling the patient's full cooperation and facilitating early diagnosis of any potential neurological deficit.

Background: The reproducible beneficial effect of constraint-induced movement therapy (CIMT) in hemiparetic stroke patients makes it a good model to study brain plasticity during rehabilitation procedures. Objective: Assess the functional brain reorganization induced by each of the two components of CIMT: (i) non-affected upper-limb constraint and (ii) intensive training of the paretic arm. Methods: Brain activity of a right hemiparetic chronic stroke patient and of 10 healthy controls was recorded with a functional magnetic resonance imaging (fMRI) during a finger opposition task. For the patient, a total of 8 assessments were performed, before and after each component of CIMT. At each time point, brain activity during movement was compared with rest. Patient's results were first compared to the control group and then correlated to motor performance across sessions. Results: Constraint-therapy-related improvement was correlated with a decrease of cerebral activity in sensory-motor regions of both the affected and the non-affected hemispheres. Intensive-therapy-related improvement was correlated with the recruitment of pre-motor cortices and cerebellum in both hemispheres. Conclusions: Two different patterns of brain activity underlie the effects of intensive training and constraint which could account for the respective effect of each component of the therapy.Competing Interest StatementThe authors have declared no competing interest.