Variation of Fault Creep Along the Overdue Istanbul-Marmara Seismic Gap in NW Türkiye

Strain energy from tectonic loading can be partly released through aseismic creep. Earthquake repeaters, repeatedly activated brittle fault patches surrounded by creep, indicate steady-state creep that affects the amount of seismic energy available for the next large earthquake along a plate contact. The offshore Main Marmara Fault (MMF) of the North Anatolian Fault Zone represents a seismic gap capable of generating a M > 7 earthquake in direct vicinity to the mega-city Istanbul. Based on a newly compiled seismicity catalog, we identify repeating earthquakes to resolve the spatial creep variability along the MMF during a 15-year period. We observe a maximum of seismic repeaters indicating creep along the central and western MMF segments tapering off toward the locked onshore Ganos fault in the west, and the locked offshore Princes Islands segment immediately south of Istanbul in the east. This indicates a high degree of spatial creep variability along the Istanbul-Marmara seismic gap

Sea Level Changes Affect Seismicity Rates in a Hydrothermal System Near Istanbul

Small stress changes such as those from sea level fluctuations can be large enough to trigger earthquakes. If small and large earthquakes initiate similarly, high-resolution catalogs with low detection thresholds are best suited to illuminate such processes. Below the Sea of Marmara section of the North Anatolian Fault, a segment of urn:x-wiley:00948276:media:grl65397:grl65397-math-0001150 km is late in its seismic cycle. We generated high-resolution seismicity catalogs for a hydrothermal region in the eastern Sea of Marmara employing AI-based and template matching techniques to investigate the link between sea level fluctuations and seismicity over 6 months. All high resolution catalogs show that local seismicity rates are larger during time periods shortly after local minima of sea level, when it is already rising. Local strainmeters indicate that seismicity is promoted when the ratio of differential to areal strain is the largest. The strain changes from sea level variations, on the order of 30–300 nstrain, are sufficient to promote seismicity

Crustal Thickness Variation Across the Sea of Marmara Region, NW Turkey: A Reflection of Modern and Ancient Tectonic Processes

The Marmara region in Turkey is an important geological setting, both from a tectonic and a seismic hazard/risk perspective. We present a new map of crustal thickness variation across this complex region to better understand the interplay of past and present tectonic processes that have formed present‐day structure. Maps of crustal thickness are created using Ps converted phases and receiver function (RF) analysis of earthquakes recorded at all publicly available seismic stations and stations in the national monitoring network (run by AFAD Disaster and Emergency Management Authority Turkey). RFs are converted from time to depth using a local 3‐D full‐waveform tomographic model and are combined in multiphase common conversion point stacks. Direct P to S converted arrivals and associated multiples are mapped to produce continuous maps of the Moho discontinuity. Results show Moho depths ranging from 26–41 km with a regional trend of westward thinning reflecting the effects of the extensional regime in western Anatolia and the neighboring Aegean Sea. The thinnest crust is observed beneath the western end of the Sea of Marmara, attributed to transtensional basin opening. A distinct region of increased crustal thickness bounded by the West Black Sea Fault in the west, and the northern strand of the North Anatolian Fault in the south, defines the ancient crustal terrane of the Istanbul Zone. Isostatic arguments indicate that the thickened crust and lower elevation in the Istanbul Zone require it to be underlain by thicker lithosphere, a conclusion that is consistent with its hypothesized origin near the Odessa shelf

Direct Evidence of a Slow‐Slip Transient Modulating the Spatiotemporal and Frequency‐Magnitude Earthquake Distribution: Insights From the Armutlu Peninsula, Northwestern Turkey

Earthquakes and slow‐slip events interact, however, detailed studies investigating their interplay are still limited. We generate the highest resolution microseismicity catalog to date for the northern Armutlu Peninsula in a ∼1‐year period to perform a detailed seismicity distribution analysis and correlate the results with a local, geodetically observed slow‐slip transient within the same period. Seismicity shows a transition of cluster‐type behavior from swarm‐like to burst‐like, accompanied by an increasing relative proportion of clustered (non‐Poissonian) relative to background (Poissonian) seismicity and gradually decreasing b‐value as the geodetically observed slow‐slip transient ends. The observed slow‐slip transient decay correlates with gradually increasing effective‐stress‐drop values. The observed correlation between the b‐value and geodetic transient highlights the influence of aseismic deformation on seismic deformation and the impact of slow‐slip transients on local seismic hazard

Months-long seismicity transients preceding the 2023 MW 7.8 Kahramanmaraş earthquake, Türkiye

Short term prediction of earthquake magnitude, time, and location is currently not possible. In some cases, however, documented observations have been retrospectively considered as precursory. Here we present seismicity transients starting approx. 8 months before the 2023 MW 7.8 Kahramanmaraş earthquake on the East Anatolian Fault Zone. Seismicity is composed of isolated spatio-temporal clusters within 65 km of future epicentre, displaying non-Poissonian inter-event time statistics, magnitude correlations and low Gutenberg-Richter b-values. Local comparable seismic transients have not been observed, at least since 2014. Close to epicentre and during the weeks prior to its rupture, only scarce seismic activity was observed. The trends of seismic preparatory attributes for this earthquake follow those previously documented in both laboratory stick-slip tests and numerical models of heterogeneous earthquake rupture affecting multiple fault segments. More comprehensive earthquake monitoring together with long-term seismic records may facilitate recognizing earthquake preparation processes from other regional deformation transients

Incidents control in radiotherapy oncology

Primer pla de l'escut del monarca del s. XVI, conservat i ubicat a la porta de la UB. Mesura 1,60 x 2,20 metre si és de pedra sorrenca

Analysis of the bearing capacity of unbound granular mixtures with rubber particles from scrap tyres when used as sub-ballast

[EN] Scrap tyres are a problematic waste material. As a method for recycling large quantities of rubber from scrap tyres, this paper analyses the use of unbound granular mixtures with varying percentages of rubber particles as sub-ballast in railway lines. Bearing capacity for such mixtures is studied in laboratory and field tests using static and dynamic plate load tests, as well as cyclic triaxial tests. It is found that adding rubber increases permanent and resilient strain and that none of the mixtures suffer plastic creep after 2.5 million cycles. Considering the usual bearing capacity requirements, the optimum rubber content is 2.5% (by weight). This percentage increases resistance to degradation while ensuring sufficient bearing capacity.Hidalgo Signes, C.; Martínez Fernández, P.; Garzón-Roca, J.; Insa Franco, R. (2016). Analysis of the bearing capacity of unbound granular mixtures with rubber particles from scrap tyres when used as sub-ballast. Materiales de Construcción. 66(324):1-15. doi:10.3989/mc.2016.11515S11566324Humphrey, D., & Blumenthal, M. (2010). The Use of Tire-Derived Aggregate in Road Construction Applications. Green Streets and Highways 2010. doi:10.1061/41148(389)25Wolfe, S. L., Humphrey, D. N., & Wetzel, E. A. (2004). Development of Tire Shred Underlayment to Reduce Groundborne Vibration from LRT Track. Geotechnical Engineering for Transportation Projects. doi:10.1061/40744(154)62Salgado, R., Yoon, S., & Siddiki, N. (2003). Construction of Tire Shreds Test Embankment. doi:10.5703/1288284313165Yoon, S., Prezzi, M., Siddiki, N. Z., & Kim, B. (2006). Construction of a test embankment using a sand–tire shred mixture as fill material. Waste Management, 26(9), 1033-1044. doi:10.1016/j.wasman.2005.10.009Sol-Sánchez, M., Thom, N. H., Moreno-Navarro, F., Rubio-Gámez, M. C., & Airey, G. D. (2015). A study into the use of crumb rubber in railway ballast. Construction and Building Materials, 75, 19-24. doi:10.1016/j.conbuildmat.2014.10.045Hidalgo Signes, C., Martínez Fernández, P., Medel Perallón, E., & Insa Franco, R. (2014). Characterisation of an unbound granular mixture with waste tyre rubber for subballast layers. Materials and Structures, 48(12), 3847-3861. doi:10.1617/s11527-014-0443-z8. PF-7 (2006) Pliego de Prescripciones Técnicas Generales de Materiales Ferroviarios PF-7: Subbalasto (General Technical Specifications for Railway Materials PF-7: Sub-ballast). Spanish Ministry of Public Works and Transport, Madrid. (In Spanish).10. Panadero, C.; Sanz, J.L. (2010) Análisis de las propiedades del sub-balasto: Contradicciones y procesos que afectan a su función (Analysis of sub-ballast properties: Contradictions and processes that affect their performance). Revista Ingeopres 196, 14–21. (In Spanish).12. Santiago, E.; García, J.L.; González, P. (2010) Comparación de diferentes métodos de control de compactación del subbalasto (Comparison of different sub-ballast compaction control methods). CEDEX Geotechnical Laboratory, Madrid. (In Spanish).Tompai, Z. (2008). Conversion between static and dynamic load bearing capacity moduli and introduction of dynamic target values. Periodica Polytechnica Civil Engineering, 52(2), 97. doi:10.3311/pp.ci.2008-2.0617. Melis, M. (2006). Terraplenes y Balasto en Alta Velocidad Ferroviaria (Embankment and ballast in high speed railways). Revista de Obras Públicas 3464, 7–36. (In Spanish).Werkmeister, S., Dawson, A. R., & Wellner, F. (2005). Permanent Deformation Behaviour of Granular Materials. Road Materials and Pavement Design, 6(1), 31-51. doi:10.1080/14680629.2005.9689998Cerni, G., Cardone, F., Virgili, A., & Camilli, S. (2012). Characterisation of permanent deformation behaviour of unbound granular materials under repeated triaxial loading. Construction and Building Materials, 28(1), 79-87. doi:10.1016/j.conbuildmat.2011.07.066Speir, R., & Witczak, M. (1996). Use of Shredded Rubber in Unbound Granular Flexible Pavement Layers. Transportation Research Record: Journal of the Transportation Research Board, 1547, 96-106. doi:10.3141/1547-1424. Santamarina, J.C.; Klein, K.A.; Fam, M.A. (2001) Soils and Waves. Particulate Materials. Behavior, Characterization and Process Monitoring. John Wiley & Sons Ltd., Baffins Lane, Chichester.25. Pe-a, M. (2003) Tramos de ensayo de vía en placa en la línea del corredor del Mediterráneo para su explotación a alta velocidad (Slab track test sites in the Mediterranean Corridor for high speed use). Revista de Obras Públicas 3431, 57–68. (In Spanish).Cecich, V., Gonzales, L., Hoisaeter, A., Williams, J., & Reddy, K. (1996). Use of Shredded Tires as Lightweight Backfill Material for Retaining Structures. Waste Management & Research, 14(5), 433-451. doi:10.1177/0734242x960140050

Transportability of non-target arthropod field data for the use in environmental risk assessment of genetically modified maize in Northern Mexico

In country, non-target arthropod (NTA) field evaluations are required to comply with the regulatory process for cultivation of genetically modified (GM) maize in Mexico. Two sets of field trials, Experimental Phase and Pilot Phase, were conducted to identify any potential harm of insect-protected and glyphosate-tolerant maize (MON89Ø34-3 × MON-88Ø17-3 and MON-89Ø34-3 × MON-ØØ6Ø3-6) and glyphosatetolerant maize (MON-ØØ6Ø3-6) to local NTAs compared to conventional maize. NTA abundance data were collected at 32 sites, providing high geographic and environmental diversity within maize production areas from four ecological regions (ecoregions) in northern Mexico. The most abundant herbivorous taxa collected included field crickets, corn flea beetles, rootworm beetles, cornsilk flies, aphids, leafhoppers, plant bugs and thrips while the most abundant beneficial taxa captured were soil mites, spiders, predatory ground beetles, rove beetles, springtails (Collembola), predatory earwigs, ladybird beetles, syrphid flies, tachinid flies, minute pirate bugs, parasitic wasps and lacewings. Across the taxa analysed, no statistically significant differences in abundance were detected between GM maize and the conventional maize control for 69 of the 74 comparisons (93.2%) indicating thatthe single or stacked insect-protected and herbicide-tolerant GM traits generally exert no marked adverse effects on the arthropod populations compared with conventional maize. The distribution of taxa observed in this study provides evidence that irrespective of variations in overall biodiversity of a given ecoregion, important herbivore, predatory and parasitic arthropod taxa within the commercial maize agroecosystem are highly similar indicating that relevant data generated in one ecoregion can be transportable for the risk assessment of the same or similar GM crop in another ecoregion