Converting InSAR- and GNSS-derived strain rate maps into earthquake hazard models for Anatolia

&amp;lt;p&amp;gt;Geodetic measurements of crustal deformation rates can provide important constraints on a region&amp;amp;#8217;s earthquake hazard that purely seismicity-based hazard models may miss. For example, geodesy might show that strain (or a deficit of seismic moment) is accumulating faster than the total rate at which known earthquakes have released it, implying that the long-term hazard may include larger earthquakes with long recurrence intervals (and/or temporal increases in seismicity rates). Conversely, the moment release rate in recent earthquakes might surpass the geodetic moment buildup rate, suggesting that the long-term-average earthquake activity and hazard may in fact may be more quiescent than might be estimated using the earthquake history alone. Such geodetic constraints, however, have traditionally been limited by poor spatial and/or temporal sampling, resulting in ambiguities about how the lithosphere accommodates strain in space and time that can bias estimates of the resulting hazard. High-resolution deformation maps address this limitation by imaging (rather than presuming and/or modelling) where and how deformation takes place. These maps are now within reach for the Alpine-Himalayan Belt &amp;amp;#8211; one of the most populous and seismically hazardous regions on Earth &amp;amp;#8211; thanks to the COMET-LiCSAR InSAR processing system, which performs large-scale automated processing and timeseries analysis of Sentinel-1 data provided by the EU&amp;amp;#8217;s Copernicus programme. We are pairing LiCSAR products with GNSS data to generate high-resolution maps of interseismic surface motion (velocity) and strain rate for the Anatolia region. Here we quantitively investigate what these strain rate distributions imply for seismic hazard in this region, using two approaches in parallel.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;First, building on previous work, we develop a fully probability-based method to pair geodesy and seismic catalogs to estimate the recurrence times of large, moderate and small earthquakes in a given region. We assume that earthquakes 1) obey a power-law magnitude-frequency distribution up to a maximum magnitude and 2) collectively release seismic moment at the same rate that we estimate it is accumulating from the strain rate maps. Iterating over various magnitude-frequency distributions and their governing parameters, and formally incorporating uncertainties in moment buildup rate and the magnitudes of recorded earthquakes, we build a probabilistic long-term-average earthquake model for Anatolia as a whole, including the most likely maximum earthquake magnitude. Second, we estimate how seismic hazard may vary from place to place within Anatolia. Using insights from dislocation models, we identify two key signatures of a locked fault in a strain rate field, allowing us to convert the newly developed strain maps to &amp;amp;#8220;effective fault maps.&amp;amp;#8221; Additionally, we explore how characteristics of earthquake magnitude-frequency distributions may scale with the rate of strain (or moment) buildup, and what these scaling relations imply for the distribution of hazard in Anatolia, using the seismic catalog to evaluate these hypotheses. We also explore the implications of our findings for seismic hazard and address how to expand these approaches to the Alpine-Himalaya Belt as a whole.&amp;lt;/p&amp;gt; </jats:p

Using digital and hand printing techniques to compensate for loss: re-establishing colour and texture in historic textiles

Conservators use a range of 'gap filling' techniques to improve the structural stability and presentation of objects. Textile conservators often use fabric supports to provide reinforcement for weak areas of a textile and to provide a visual infill in missing areas. The most common technique is to use dyed fabrics of a single colour but while a plain dyed support provides good reinforcement, it can be visually obtrusive when used with patterned or textured textiles. Two recent postgraduate dissertation projects at the Textile Conservation Centre (TCC) have experimented with hand printing and digital imaging techniques to alter the appearance of support fabrics so that they are less visually obtrusive and blend well with the colour and texture of the textile being supported. Case studies demonstrate the successful use of these techniques on a painted hessian rocking horse and a knitted glove from an archaeological context

Numerical study of linear and circular model DNA chains confined in a slit: metric and topological properties

Advanced Monte Carlo simulations are used to study the effect of nano-slit confinement on metric and topological properties of model DNA chains. We consider both linear and circularised chains with contour lengths in the 1.2--4.8 $\mu$m range and slits widths spanning continuously the 50--1250nm range. The metric scaling predicted by de Gennes' blob model is shown to hold for both linear and circularised DNA up to the strongest levels of confinement. More notably, the topological properties of the circularised DNA molecules have two major differences compared to three-dimensional confinement. First, the overall knotting probability is non-monotonic for increasing confinement and can be largely enhanced or suppressed compared to the bulk case by simply varying the slit width. Secondly, the knot population consists of knots that are far simpler than for three-dimensional confinement. The results suggest that nano-slits could be used in nano-fluidic setups to produce DNA rings having simple topologies (including the unknot) or to separate heterogeneous ensembles of DNA rings by knot type.Comment: 12 pages, 10 figure

Postseismic Deformation Following the 2015 M_w7.8 Gorkha (Nepal) Earthquake: New GPS Data, Kinematic and Dynamic Models, and the Roles of Afterslip and Viscoelastic Relaxation

We report Global Positioning System (GPS) measurements of postseismic deformation following the 2015 M_w7.8 Gorkha (Nepal) earthquake, including previously unpublished data from 13 continuous GPS stations installed in southern Tibet shortly after the earthquake. We use variational Bayesian Independent Component Analysis (vbICA) to extract the signal of postseismic deformation from the GPS time series, revealing a broad displacement field extending >150 km northward from the rupture. Kinematic inversions and dynamic forward models show that these displacements could have been produced solely by afterslip on the Main Himalayan Thrust (MHT) but would require a broad distribution of afterslip extending similarly far north. This would require the constitutive parameter (a − b)σ to decrease northward on the MHT to ≤0.05 MPa (an extreme sensitivity of creep rate to stress change) and seems unlikely in light of the low interseismic coupling and high midcrustal temperatures beneath southern Tibet. We conclude that the northward reach of postseismic deformation more likely results from distributed viscoelastic relaxation, possibly in a midcrustal shear zone extending northward from the seismogenic MHT. Assuming a shear zone 5–20 km thick, we estimate an effective shear‐zone viscosity of ~3·10¹⁶–3·10¹⁷ Pa·s over the first 1.12 postseismic years. Near‐field deformation can be more plausibly explained by afterslip itself and implies (a − b)σ ~ 0.5–1 MPa, consistent with other afterslip studies. This near‐field afterslip by itself would have re‐increased the Coulomb stress by ≥0.05 MPa over >30% of the Gorkha rupture zone in the first postseismic year, and deformation further north would have compounded this reloading

Out of Asia? Expansion of Eurasian Lyme borreliosis causing genospecies display unique evolutionary trajectories

Vector-borne pathogens exist in obligate transmission cycles between vector and reservoir host species. Host and vector shifts can lead to geographic expansion of infectious agents and the emergence of new diseases in susceptible individuals. Three bacterial genospecies (Borrelia afzelii, Borrelia bavariensis, and Borrelia garinii) predominantly utilize two distinct tick species as vectors in Asia (Ixodes persuicatus) and Europe (Ixodes ricinus). Through these vectors, the bacteria can infect various vertebrate groups (e.g., rodents, birds) including humans where they cause Lyme borreliosis, the most common vector-borne disease in the Northern hemisphere. Yet, how and in which order the three Borrelia genospecies colonized each continent remains unclear including the evolutionary consequences of this geographic expansion. Here, by reconstructing the evolutionary history of 142 Eurasian isolates, we found evidence that the ancestors of each of the three genospecies probably have an Asian origin. Even so, each genospecies studied displayed a unique substructuring and evolutionary response to the colonization of Europe. The pattern of allele sharing between continents is consistent with the dispersal rate of the respective vertebrate hosts, supporting the concept that adaptation of Borrelia genospecies to the host is important for pathogen dispersal. Our results highlight that Eurasian Lyme borreliosis agents are all capable of geographic expansion with host association influencing their dispersal;further displaying the importance of host and vector association to the geographic expansion of vector-borne pathogens and potentially conditioning their capacity as emergent pathogens