Largest recent impact craters on Mars: Orbital imaging and surface seismic co-investigation.

Two >130-meter-diameter impact craters formed on Mars during the later half of 2021. These are the two largest fresh impact craters discovered by the Mars Reconnaissance Orbiter since operations started 16 years ago. The impacts created two of the largest seismic events (magnitudes greater than 4) recorded by InSight during its 3-year mission. The combination of orbital imagery and seismic ground motion enables the investigation of subsurface and atmospheric energy partitioning of the impact process on a planet with a thin atmosphere and the first direct test of martian deep-interior seismic models with known event distances. The impact at 35°N excavated blocks of water ice, which is the lowest latitude at which ice has been directly observed on Mars

Women and competition in elimination tournaments: evidence from professional tennis data

This article examines how professional female tennis players react to (a) prize incentives and (b) heterogeneity in ex ante players' abilities. It is found that a larger prize spread encourages women to increase effort, even when controlling for many tournament and player characteristics. Further results indicate that uneven contests lead favorites to win more games and underdogs to be less performing. They also show that the performance differential among players increases with the ranking differential. These findings suggest that the outcome of a match is more linked to players' abilities than to players' incentives to adjust effort according to success chances.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Setting the stage for marine spatial planning: ecological and social data collation and analyses in Canada's Pacific waters

Canada's Pacific coast is one region where there is a renewed commitment to pursue marine spatial planning (MSP). The British Columbia Marine Conservation Analysis (BCMCA) project aimed to set the stage for MSP, and was designed to provide resource managers, scientists, decision-makers, and stakeholders with a new set of resources to inform coast-wide integrated marine planning and management initiatives. Geographic Information Systems and the decision support tool Marxan were used to develop two main products: (1) an atlas of known marine ecological values and human uses; and (2) analyses of areas of conservation value and human use value. 110 biophysical datasets and 78 human use datasets were collated and refined where applicable, as identified through five ecological expert workshops, one expert review of physical marine classification and representation, and guidance from the human use data working group. Ecological data richness maps and Marxan results show the importance of nearshore and continental shelf regions. Data richness maps for the six categories of human uses show that all, except shipping and transport, are also closely linked to the shoreline and continental shelf. An example ecological Marxan solution identifying areas of conservation value overlapped human use sector footprints by percentages ranging from 92% (i.e., 92% of planning units selected by Marxan also contain commercial fisheries) to 3%. The experience of the BCMCA project has the potential to provide valuable guidance to regions seeking to jump-start planning processes by collating spatial information and carrying out exploratory analyses

Lithospheric low-velocity zones associated with a magmatic segment of the Tanzanian Rift, East Africa

International audienceRifting in a cratonic lithosphere is strongly controlled by several interacting processes including crust/mantle rheology, magmatism, inherited structure and stress regime. In order to better understand how these physical parameters interact, a 2 yr long seismological experiment has been carried out in the North Tanzanian Divergence (NTD), at the southern tip of the eastern magmatic branch of the East African rift, where the southward-propagating continental rift is at its earliest stage. We analyse teleseismic data from 38 broad-band stations ca. 25 km spaced and present here results from their receiver function (RF) analysis. The crustal thickness and Vp/Vs ratio are retrieved over a ca. 200 × 200 km2 area encompassing the South Kenya magmatic rift, the NTD and the Ngorongoro-Kilimanjaro transverse volcanic chain. Cratonic nature of the lithosphere is clearly evinced through thick (up to ca. 40 km) homogeneous crust beneath the rift shoulders. Where rifting is present, Moho rises up to 27 km depth and the crust is strongly layered with clear velocity contrasts in the RF signal. The Vp/Vs ratio reaches its highest values (ca. 1.9) beneath volcanic edifices location and thinner crust, advocating for melting within the crust. We also clearly identify two major low-velocity zones (LVZs) within the NTD, one in the lower crust and the second in the upper part of the mantle. The first one starts at 15–18 km depth and correlates well with recent tomographic models. This LVZ does not always coexist with high Vp/Vs ratio, pleading for a supplementary source of velocity decrease, such as temperature or composition. At a greater depth of ca. 60 km, a mid-lithospheric discontinuity roughly mimics the step-like and symmetrically outward-dipping geometry of the Moho but with a more slanting direction (NE–SW) compared to the NS rift. By comparison with synthetic RF, we estimate the associated velocity reduction to be 8–9 per cent. We relate this interface to melt ponding, possibly favouring here deformation process such as grain-boundary sliding (EAGBS) due to lithospheric strain. Its geometry might have been controlled by inherited lithospheric fabrics and heterogeneous upper mantle structure. We evidence that crustal and mantle magmatic processes represent first order mechanisms to ease and locate the deformation during the first stage of a cratonic lithospheric breakup