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The 2019-11-1, Mw4.9 Le Teil earthquake occurred within the NE termination of the Cévennes faults system (CFS) in southern France, along the La Rouvière fault (LRF), an Oligocene normal fault which was not known to be potentially active. This shallow moderate magnitude reversefaulting event produced a 5 km-long surface rupture and strong ground shaking. No evidence of previous quaternary activity was observed in the morphology, raising the question whether the fault had been reactivated for the first time since the Oligocene or had broken the surface in the past without being detected in the morphology. To address this issue, we carried out paleoseismological investigations to analyze and characterize evidences of paleo-ruptures in Quaternary deposits. We discovered that at least one event prior 2019, occurred between 13.5 and 3.3 ka within the central part of the fault segment that broke in 2019, and that a possible earlier surfacerupturing event occurred within the northern part of this segment during the 16th century. Further investigations coupling sub-surface geophysical investigations and trenching are now carried out within the southern and northern segments of the LRF as well as along the other fault segments of the CFS.

The M w 7.9 2015 April 25 Gorkha earthquake is the latest of a millenary-long series of large devastating Himalayan earthquakes. It is also the first time a large Himalayan earthquake and its aftershocks were recorded by a local network of seismic stations. In the 5 yr following the main shock, more than 31 000 aftershocks were located by this permanent network within the ruptured area, including 14 362 events with M L greater than 2.5, 7 events with M L > 6, including one large aftershock with M w 7.2 on 2015 May 12. In 2020, 5 yr after the main shock, the seismicity rate along the ruptured fault segments was still about 5 times higher than the background seismicity before the Gorkha earthquake. Several bursts of earthquakes, sometimes organized in clusters, have been observed from a few days to several years after the main shock. Some of these clusters were located at the same place as the clusters that happened during the decades of interseismic stress build-up that preceded the large earthquake. They also happened in the vicinity of the high frequency seismic bursts that occurred during the main shock. These heterogeneities contribute to a persistent segmentation of the seismicity along strike, possibly controlled by geological structural complexities of the Main Himalayan Thrust fault. We suggest that these pre-2015 clusters revealed the seismo-geological segmentation that influences both the coseismic rupture and the post-seismic relaxation. [ABSTRACT FROM AUTHOR]

[1] The Lesser Himalaya (LH) consists of metasedimentary rocks that have been scrapped off from the underthrusting Indian crust and accreted to the mountain range over the last ~20 Myr. It now forms a significant fraction of the Himalayan collisional orogen. We document the kinematics and thermal metamorphism associated with the deformation and exhumation of the LH, combining thermometric and thermochronological methods with structural geology. Peak metamorphic temperatures estimated from Raman spectroscopy of carbonaceous material decrease gradually from 520[degrees]-550[degrees]C below the Main Central Thrust zone down to less than 330[degrees]C. These temperatures describe structurally a 20[degrees]50[degrees]C/km inverted apparent gradient. The Ar muscovite ages from LH samples and from the overlying crystalline thrust sheets all indicate the same regular trend; i.e., an increase from about 34 Manear the front of the high range to about 20 Ma near the leading edge of the thrust sheets, about 80 km to the south. This suggests that the LH has been exhumed jointly with the overlying nappes as a result of overthrusting by about 5 mm/yr. For a convergence rate of about 20 mm/yr, this implies underthrusting of the Indian basement below the Himalaya by about 15 mm/yr. The structure, metamorphic grade and exhumation history of the LH supports the view that, since the mid-Miocene, the Himalayan orogen has essentially grown by underplating, rather than by frontal accretion. This process has resulted from duplexing at a depth close to the brittle-ductile transition zone, by southward migration of a midcrustal ramp along the Main Himalayan Thrust fault, and is estimated to have resulted in a net flux of up to 150 [m.sup.2]/yr of LH rocks into the Himalayan orogenic wedge. The steep inverse thermal gradient across the LH is interpreted to have resulted from a combination of underplating and post metamorphic shearing of the underplated units. INDEX TERMS: 8102 Tectonophysics: Continental contractional orogenic belts; 8122 Tectonophysics: Dynamics, gravity and tectonics; 9320 Information Related to Geographic Region: Asia; KEYWORDS: Himalaya, thermal structure, underplating, duplex, metamorphism, thermochronology. Citation: Bollinger, L., J. P. Avouac, O. Beyssac, E. J. Catlos, T. M. Harrison, M. Grove, B. Goffe, and S. Sapkota (2004), Thermal structure and exhumation history of the Lesser Himalaya in central Nepal.

Unravelling relations between lateral variations of mid-crustal seismicity and the geometry of the Main Himalayan Thrust (MHT) system at depth is a key issue in seismotectonic studies of the Himalayan range. These relations can reveal along strike changes in the behaviour of the fault at depth related to fluids or the local ramp-flat geometry and more generally of the stress build-up along the fault. Some of these variations may control the rupture extension of intermediate, large or great earthquakes, the last of which dates back from 1505 CE in far western Nepal. The region is also associated to lateral spatio-temporal variations of the mid-crustal seismicity monitored by the Regional Seismic Network of Surkhet–Birendranagar. This network was supplemented between 2014 and 2016 by 15 temporary stations deployed above the main seismic clusters giving new potential to regional studies. Both absolute and relative locations together with focal mechanisms are determined to gain insight on the fault behaviour at depth. We find more than 4000 earthquakes within 5 and 20 km-depth clustered in three belts parallel to the front of the Himalayan range. Finest locations reveal close relationships between seismic clusters and fault segments at depth among which mid-crustal ramps and reactivated tectonic slivers. Our results support a geometry of the MHT involving several fault patches at depth separated by ramps and tear faults. This geometry most probably affects the pattern of the coseismic ruptures breaking partially or totally the locked fault zone as well as eventual along strike variations of seismic coupling during interseismic period. [ABSTRACT FROM AUTHOR]

Metropolitan France is a region of slow tectonic deformation with sparse seismicity. On 11 November 2019, the M L 5.4 Le Teil earthquake became the largest seismic event recorded in the last 16 yr. This event was recorded by the national seismic networks and also by a wide variety of other geophysical techniques including infrasound and InSAR measurements. These complementary technologies offer the opportunity to investigate in detail the earthquake source characteristics and the associated ground motion attenuation. Both seismic waveform inversions and InSAR interferogram reveal a shallow rupture on a reverse fault with an associated moment magnitude of 4.8–4.9. Infrasound signals also provide fast evidences pointing towards the area of ground surface displacements, which coincides with La Rouvière fault, in the Cévennes fault system, known as a formerly active normal fault during the Oligocene. The very significant amount of seismic records also helps towards validating the GMPE laws available for the region. This multitechnology characterization documents the kinematics of this rare example of shallow intraplate fault reactivation. [ABSTRACT FROM AUTHOR]

The ∼ M 6 1799 Bouin earthquake is considered as one of the largest earthquakes to have struck Western France. However, the seismogenic source potentially responsible for this event remain marginally documented. We present results from a focused offshore-onshore multidisciplinary survey in its meizoseismal area in order to identify the fault segments that potentially ruptured during this earthquake. Based on macroseismic data and the geology, we focused our study on the so-called Machecoul Fault as a potential source of the 1799 Bouin event. Our survey includes extensive high-resolution seismic reflection, high resolution bathymetry and a 1-yr seismological survey. These data were combined with existing topography, onshore gravity data and drill data to document the geometry of the Marais Breton/Baie de Bourgneuf basin, the past tectonic activity and the current local microearthquakes at depth along its bounding faults. Offshore and onshore observations suggest a recent activity of the segmented Machecoul Fault bounding the basin to the North. Offshore, the planar contact between the Plio-Quaternary sediments and the basement along the fault trace as well as the thickening of these sedimentary units near this contact suggests tectonic control rather than erosion. Onshore, the recent incision of the footwall of the fault suggests a recent tectonic activity. The temporary local seismological experiment deployed between 2016 and 2017 recorded a diffuse microseismicity down to the depth of 22 ± 5 km along the southward dipping Machecoul Fault, associated with predominantly normal fault mechanisms. Altogether, these results suggest that the Machecoul Fault is a serious candidate for being the source of the historical Bouin 1799 earthquake. [ABSTRACT FROM AUTHOR]

The Charnath Khola is a large river crossing the Himalayan thrust system in the region devastated by the great M8.3 1934 Bihar‐Nepal earthquake. Fluvial terraces are abandoned along the river and at the base of a ~20‐m high cumulative thrust escarpment. A trench across the fault scarp exposed Siwalik mudstone/siltstone overthrusting Quaternary units and three colluvial wedges interfingered with fluvial sands. The 85 accelerator mass spectrometry radiocarbon dates, from detrital charcoals sampled in the trench, a river cut and river terraces, constrain the timing of the sedimentary processes following the last two major earthquakes, in 1934 and 1255 CE. Although several samples straddle the main earthquake horizon, associating it with the 1934 earthquake, based solely on radiocarbon ages, remains challenging. The 49 detrital charcoal ages found in the pre‐earthquake and postearthquake units fall between 65 and 225 BP, a period with a flat calibration curve. Many of these radiocarbon ages are suspected to include a part due to inbuilt time (i.e., age of the wood at the time of burning), transport time, and reworking processes, which are difficult to resolve. Considering these ages at their face value could lead to dates older than the actual earthquake dates. We suggest that a part of this chronological bias is also related to a local postseismic aggradation pulse of 4 to 5 m of sediments, which is documented in the trench and terraces. This fluvial sequence, hiding the most recent surface rupture, is likely related to landslide‐sediment deposition triggered by the 1934 Bihar‐Nepal earthquake. Key Points: Evidence for 1934 and 1255 AD surface ruptures at Charnath Khola, eastern NepalAggradation pulses at the Charnath Khola follow large surface rupturing earthquakesOverlooking the predeposit processes of detrital charcoal samples could lead to paleo‐earthquake dates older than the actual earthquake dates [ABSTRACT FROM AUTHOR]

Highlights • First temporary seismological network in western Nepal. • Resolution of local hypocenters along the downdip end of the Main Himalayan Thrust. • Clustered seismicity develops at the intersection of Lesser Himalayan tectonic slivers. • Seismic swarms migrate at 50 m/day at the transition zone. • Earthquakes reveal the geometry of the fault leading to a new segmentation model. Abstract The midcrustal seismicity along the Himalayas depicts some lateral variations. This seismicity is often related to stress build up, at depth, along the downdip extent of the fault segments producing large and great earthquakes. To better characterize these variations, we deployed the first temporary seismological network in West Nepal (HiKNet) as a complement to the Nepalese national network. We used automatic picks, manually validated, to perform absolute and relative location of the earthquakes. The resulting catalog contains 2190 local events, shallow to midcrustal (8–16 km). The comparison between the seismicity and the geologic balanced cross-sections shows that most earthquakes occur within the hanging wall of the Main Himalayan Thrust fault nearby ramps or suspected contacts between Lesser Himalayan slivers. Some of the events associated with these geological structures are clustered within weeks-long earthquake swarms with seismic envelopes migrating at 35–50 m/day. These transients are possibly related to fluid migrations or geodetically unresolved slow slip events. The lateral variations of some of the structures associated to this seismicity are likely partially controlling the extent of the coseismic ruptures during intermediate earthquakes that break partly the locked fault zone, in a similar way to what was reported after the Mw7.8 2015 Gorkha-Nepal earthquake. A better characterization of the faults segmentation, including a better location and extent of the seismogenic segments at depth, is an important input for seismic hazard studies. [ABSTRACT FROM AUTHOR]

Background: Infants with HIV infection, particularly those infected in utero, who do not receive antiretroviral therapy (ART) have high mortality in the first year of life. Virologic diagnostic testing is recommended by the World Health Organization between ages 4 and 6 weeks after birth. However, adding very early infant diagnosis (VEID) testing at birth has been suggested to enable earlier diagnosis and rapid treatment of in utero infection. We assessed the costs of adding VEID to the standard 6-week testing in Lesotho where coverage of PMTCT services is nearly universal. Methods: Retrospective cost data were collected at eight health-care facilities in three districts participating in an observational prospective study that included birth testing as well as at the National Reference Laboratory in Lesotho, to investigate the cost-per-infection identified. Extrapolating to the national level, it was possible to estimate the impact of VEID on the identification of HIV-infected infants. Results: The unit cost-per-VEID test in Lesotho in 2015 was $40.50. Major cost drivers were supplies/commodities (46%) and clinical labor (22%). In 2015, 66.3% of cohort study infants born at study facilities underwent VEID; one out of 199 infants had a positive HIV DNA PCR test at birth (0.5% potential in utero infection), yielding a cost of $8,060 per HIV-positive infant identified. Sensitivity analysis showed costs based on Lesotho costing data ranged from $810 to $16,194 per-infected child with varying in utero infection rates from 5% and 0.25%, respectively. With 11,157 HIV-exposed births nationally from pregnant women on PMTCT, 66.3% VEID coverage, and 0.5% in utero infection, 37 infants infected with HIV could have been identified at birth in 2015 and 8 early infant deaths potentially averted with immediate ART compared with waiting for 6-week testing. Conclusion: If Lesotho costing data from this pilot study were applied to different epidemic circumstances, the cost-per-infected child identified by adding VEID birth testing to standard 6-week testing was lowest when in utero infection rates were high (when HIV prevalence is high and PMTCT coverage is low). [ABSTRACT FROM AUTHOR]

The midcrustal seismicity along the Main Himalayan Thrust in Nepal presents lateral variations along the rupture of the 2015 Gorkha earthquake. In order to resolve these variations, we relocate the seismicity north of Kathmandu, during a period well covered by the Nepal National Seismological Network, using a double-difference algorithm. The 550 relocated events highlight a complex pattern of clustered seismicity within the unstable-stable transition zone. Part of the seismicity is densely clustered on a southward dipping plane which ruptured on January 31st 1997 (ML = 5.8), activating a backthrust with a geometry consistent with the centroid moment tensor of this event calculated in this study. At its eastern end, the midcrustal cluster is offset by 20 km to the south suggesting the presence of a tear fault. The analysis of the time sequence allows constraining a scenario involving stress transfer between these local midcrustal structures, beginning more than one month before the 1997 main shock. The temporal evolution of the seismicity is strikingly similar for two other transient seismic swarm episodes which developed hundreds of kilometers apart along the Main Himalayan Thrust at the same time. The local stress field appears responsible for the higher sensitivity of these regions to subtle strain transients developing along the Main Himalayan Thrust. [ABSTRACT FROM AUTHOR]

The growing importance of links between the social and technical dimensions of the electricity infrastructure mean that many research problems cannot be effectively addressed without joint consideration of social and technical dynamics. This paper motivates the need for and introduces a tool to facilitate the development of linked social and technical models of electric power systems. The tool, called MatpowerConnect, enables the runtime linkage of Netlogo -- an oft-used modelling platform in the social simulation domain -- with Matpower -- a common power flow simulation package in the power systems domain. MatpowerConnect opens up new modelling possibilities for social simulation researchers active in the study of electricity systems. It offers ease of use coupled with a high degree of realism with which electricity infrastructure functionality is captured. We describe the development and use of two demonstration models using MatpowerConnect. These models illustrate two types of problems and system scales that can be addressed. In the first model we explore the consequences of actors' adaptive strategies on the performance of a small-scale power system. In the second model we simulate the effects of different regulatory regimes on network investment in a supra-national electricity transmission system to explore the long-term consequences for network development and social welfare. In both cases, the extension enables capturing a critical functionality of electric power systems, while allowing model development efforts to focus on social simulation aspects. Resources for using the extension are provided in conjunction with this paper. [ABSTRACT FROM AUTHOR]

This paper reports the development and results of a model exploring the resilience of the Dutch electricity transmission infrastructure to extreme weather events. Climate change is anticipated to result in an increase in the frequency and severity of extreme weather events over the coming decades. Situated in a low-lying coastal delta, the Netherlands may be particularly exposed to certain types of extreme weather(-induced) events. The degree to which the country's electricity network may prove resilient in the face of these future events is an open question. The model focuses on two types of extreme events - floods and heat waves - and assesses two types of adaptation measures - substation flood protections and demand-side management. The model employs a network-based approach in assessing infrastructure resilience - explicitly representing the structure and properties of the Dutch transmission infrastructure - and extends previous work by accounting for key power system characteristics such as capacity constraints and cascading failures. From a practice perspective, the results offer a first indication of the vulnerability of the Dutch electricity transmission infrastructure in the context of climate change. These results suggest that the network displays some vulnerability to both floods and heat waves. Both types of adaptation measures tested are found to enhance resilience, though substation flood protection shows greater benefits. Whilst the model was specifically developed for the study of electricity networks, we anticipate that this method may also be applicable to other types of transport infrastructures. [ABSTRACT FROM AUTHOR]

The M 7.8 2015 April 25 Gorkha earthquake devastated the mountainous southern rim of the High Himalayan range in central Nepal. The main shock was followed by 553 earthquakes of local magnitude greater than 4.0 within the first 45 days. In this study, we present and qualify the bulletin of the permanent National Seismological Centre network to determine the spatio-temporal distribution of the aftershocks. The Gorkha sequence defines a ~140-km-long ESE trending structure, parallel to the mountain range, abutting on the presumed extension of the rupture plane of the 1934 M 8.4 earthquake. In addition, we observe a second seismicity belt located southward, under the Kathmandu basin and in the northern part of the Mahabarat range. Many aftershocks of the Gorkha earthquake sequence have been felt by the 3 millions inhabitants of the Kathmandu valley. [ABSTRACT FROM AUTHOR]

The need for more sustainable, liveable and resilient cities demands improved methods for studying urban infrastructures as integrated wholes. Progress in this direction would be aided by the ability to effectively reuse and integrate existing computational models of urban systems. Building on the concept of multi-model ecologies, this paper describes ongoing efforts to facilitate model reuse and integration in the Holistic Urban Energy Simulation (HUES) platform - an extendable simulation environment for the study of urban multi-energy systems. We describe the design and development of a semantic wiki as part of the HUES platform. The purpose of this wiki is to enable the sharing and navigation of model metadata – essential information about the models and datasets of the platform. Each model and dataset in the platform is represented in the wiki in a structured way to facilitate the identification of opportunities for model reuse and integration. As the platform grows, this will help to ensure that it develops coherently and makes efficient use of existing formalized knowledge. We present the core concepts of multi-model ecologies and semantic wikis, the current state of the platform and associated wiki, and a case study demonstrating their use and benefit. [ABSTRACT FROM AUTHOR]

Many industrial ecology models may be classified as single-use products-constructed to address a specific problem and of little use beyond their original context. But a knowledge ecosystem based around single-use representations of reality wastes effort and resources and limits the impact of industrial ecology as a field. In recent years, tangible progress has been made in areas such as integrated modeling and multisimulation. However, this work tends to discount the evolutionary nature of models and their embeddedness within a changing sociotechnical environment-aspects which, we argue, are central to enabling the sustained usefulness of models in industrial ecology. We define a multimodel ecology as an interacting group of models coevolving with one another in a dynamic sociotechnical environment. A multimodel ecology perspective can facilitate model integration and reuse and highlight different ways in which models-mental, conceptual, and computational-may interact and evolve. To demonstrate the use of this perspective, we introduce and analyze an existing multimodel ecology-the Energy Modeling Laboratory. We conclude with a set of guidelines for facilitating model reuse and integration. Among others, these include use open standards, build simple components, leverage the Web, borrow proudly, and enforce sharing. [ABSTRACT FROM AUTHOR]

Little is known about the impact of combination HIV prevention interventions for men who have sex with men (MSM) and the impacts on the wider epidemics. Modelling analyses of MSM-specific interventions across varied HIV epidemics may inform evidence-based responses. The Goals model was adapted to project the impacts of providing HIV interventions for MSM and access to expanded coverage of antiretroviral therapy (ART) for adults to measure the effects on the MSM and adult epidemics in Peru, Ukraine, Kenya and Thailand. Positive impacts were observed in all four countries. Across epidemics, 14-25% of infections among MSM may be averted between 2012 and 2016 when MSM interventions are brought to scale and MSM have equal access to expanded ART for adults. Among adults, MSM interventions may avert up to 4000 new infections, in addition to the benefits associated with increased ART. Greatest impacts from expanded interventions were observed in countries where same sex transmission contributes significantly to the HIV epidemic. While significant benefits are observed among the adult and MSM populations with expansion of ART, consideration should be given to the synergies of combining ART expansion with targeted interventions to reach hidden, high-risk populations for HIV testing and counselling and linkages to care. [ABSTRACT FROM AUTHOR]

Summary Substance flow analysis (SFA) is a frequently used industrial ecology technique for studying societal metal flows, but it is limited in its ability to inform us about future developments in metal flow patterns and how we can affect them. Equation-based simulation modeling techniques, such as dynamic SFA and system dynamics, can usefully complement static SFA studies in this respect, but they are also restricted in several ways. The objective of this article is to demonstrate the ability of agent-based modeling to overcome these limitations and its usefulness as a tool for studying societal metal flow systems. The body of the article summarizes the parallel implementation of two models-an agent-based model and a system dynamics model-both addressing the following research question: What conditions foster the development of a closed-loop flow network for metals in mobile phones? The results from in silico experimentation with these models highlight three important differences between agent-based modeling (ABM) and equation-based modeling (EBM) techniques. An analysis of how these differences affected the insights that could be extracted from the constructed models points to several key advantages of ABM in the study of metal flow systems. In particular, this analysis suggests that a key advantage of the ABM technique is its flexibility to enable the representation of societal metal flow systems in a more native manner. This added flexibility endows modelers with enhanced leverage to identify options for steering metal flows and opens new opportunities for using the metaphor of an ecosystem to understand metal flow systems more fully. [ABSTRACT FROM AUTHOR]

The article discusses various papers published in this issue including one by Huibregtse et al. on adaptation in road networks, one by Pant et al. on the use of a comprehensive spatial vulnerability analysis in railway infrastructure networks, and one by Chhetri et al. on port operations.

The AIDS pandemic will enter its fiftieth year in 2031. Despite much progress, there are thirty-three million infected people worldwide, and 2.3 million adults were newly infected in 2007. Without a change in approach, a major pandemic will still be with us in 2031. Modeling carried out for the AIDS 2031 project suggests that funding required for developing countries to address the pandemic could reach $35 billion annually by 2031-three times the current level. Even then, more than a million people will still be newly infected each year. However, wise policy choices focusing on high-impact prevention and efficient treatment could cut costs by half. Investments in new prevention tools and major behavior-change efforts are needed to spur more rapid advances. Existing donors, middle-income countries with contained epidemics, philanthropists, and innovative financing could help bridge the likely funding gap. [ABSTRACT FROM AUTHOR]

Underthrusting of the Indian lithosphere beneath the Himalayas occurs during the Quaternary period along a gently north-dipping main basal detachment (main Himalayan thrust: MHT), from which the southernmost emergent ramp (main frontal thrust: MFT) branches. Historical seismicity shows that slip on the MHT is frequently accommodated through shallow earthquakes, but shows a seismic gap in western Nepal. This absence of major historical earthquakes in western Nepal can be explained either by an aseismic slip on the MHT or a long-lived elastic strain accumulation. To test these hypotheses, the present-day displacement field has been measured for a GPS network formed of 35 sites. The updated solution presented in this paper combines data from 1995, 1997, 1998 and 2000 measurements. The lack of deformation (less than ) through the outer belt does not fit with a regional aseismic slip along the southern part of MHT. A less than 3 mm yr−1 aseismic slip could nonetheless affect restricted areas of the outer belt. In contrast, a strain accumulation of more than is measured south of the Higher Himalayas, in a zone where an intense microseismicity reflects a stress build-up. It is presumably generated by locking of the aseismic creep that occurs along the MHT beneath the Higher Himalayas and Tibet. The displacement field is simulated by a dual-dislocation model that takes into account the pattern of microseismicity, and particularly a segmentation between central and western Nepal. The best fit between the measured and simulated displacement fields is obtained with 19 mm yr−1 thrust and 0–1 mm yr−1 dextral strike-slip components along a 117°NE dislocation locked to a depth of 20–21 km beneath western Nepal, and 19–20 mm yr−1 thrust and 0–2 mm yr−1 dextral strike-slip components along a 108°NE dislocation locked to a depth of 17–21 km beneath central Nepal. The width of the locked zone between the main frontal thrust and the creeping zone is of the same order, but rather greater, in western Nepal than in central Nepal. Therefore it is expected that earthquakes could occur in western Nepal. [ABSTRACT FROM AUTHOR]