Despite their importance for understanding faulting processes in volcanic environments, the source scaling of volcano-tectonic earthquakes remains poorly constrained, mainly due to the difficulty of measuring their source parameters. We analyze source parameters such as seismic moments () and corner frequencies () of several thousand volcano-tectonic earthquakes that occurred below the summit of the Piton de la Fournaise (PdF) volcano between 2014 and 2023. This swarm seismicity, preceding frequent PdF eruptions, occurs on a ring-fault system, regularly forced by pressurizations of the shallow magma reservoir and stresses caused by the pre-eruptive dike propagation. We use 3-component broadband stations located within short epicentral distances (). Coda amplitude envelopes estimated using narrow-band filters are inverted to simultaneously extract the frequency-dependent coda decay factors, site effects, and source terms. The latter are used to compute the source spectral ratios between event pairs, resulting in statistically estimated and relative , calibrated using well-constrained magnitudes. For very small earthquakes values are extrapolated beyond the Nyquist frequency, extending the reach of conventional spectral analyses. We find an average stress-drop of the order of for the majority of shallow PdF earthquakes and a general trend , consistent with the scaling observed for tectonic earthquakes, suggesting similar faulting physics in volcanic and tectonic environments. Given that the coda shape remained unchanged over 10 years of eruptions and stress drops varied insignificantly in space and time, this seismicity is associated mostly with a pre-existing fault system without the formation of new cracks.
Whole-genome sequencing (WGS) provides high-resolution insight into the genetic diversity, transmission dynamics, and drug-resistance mechanisms of Mycobacterium tuberculosis (MTB), yet genomic data from Morocco remain limited. In this study, we analyzed 68 WGS datasets of Moroccan MTB isolates and contextualized them using 19 global reference genomes. Lineages and resistance-associated mutations were determined with TB-Profiler. Pairwise single-nucleotide polymorphism (SNP) distances, phylogeny and transmission clusters were defined using well-established SNP thresholds implemented in the MTBseq pipeline. In silico spoligotypes were further compared with the SITVITEXTEND database to place Moroccan isolates in a broader regional context. Results demonstrated that circulating MTB strains in Morocco were dominated by Euro-American Lineage 4 (89.7%), with a smaller contribution from the Beijing lineage (L2.2.1). Resistance to rifampicin and isoniazid was mainly driven by canonical rpoB Ser450Leu and katG Ser315Thr mutations, while resistance to other drugs involved diverse variants. Seventeen genomic clusters encompassing 73.5% of isolates were identified, including nine clusters with isolates differing by 0-5 SNPs, consistent with very recent transmission. Multidrug-resistant and pre-extensively drug-resistant isolates were disproportionately concentrated within LAM 4.3 and Beijing sub-lineages. Spoligotyping comparisons confirmed the predominance of Euro-American lineages across Morocco and neighboring Mediterranean countries. This first comprehensive WGS-based analysis provides crucial insights into the molecular epidemiology of tuberculosis in Morocco, emphasizing the importance of integrating genomic tools into national TB control programs. Understanding the genetic landscape and transmission pathways of M. tuberculosis will support more effective public health strategies aimed at reducing TB incidence and preventing the spread of drug-resistant strains.
Here, we report the genome assembly and annotation of two clinical isolates of Naegleria fowleri from primary amebic meningoencephalitis cases in Costa Rica in 2020 using Illumina sequencing. Each assembly comprised 37 reference-guided scaffolds, with genome sizes of approximately 28 Mbp and a GC content of 36.87%.
The Tin Hallen area (Ahnet terrane, NW Hoggar, Algeria) represents one of the most well-preserved examples of blueschist-facies metamorphism in West Gondwana, associated with FeTi garnet-bearing metagabbros. The textural analysis reveals four distinct stages. The first stage (M1) is magmatic, characterized by an orthopyroxene, plagioclase +/- clinopyroxene, and ilmenite assemblage, primarily observed in areas distant from shear zones. The second stage (M2) involves the development of granulite-facies coronae and symplectites composed of garnet, clinopyroxene2, quartz, rutile, and brown amphibole. The third stage (M3) is defined by the appearance of green amphibole, sphene and epidote. Finally, the fourth stage (M4) is marked by the formation of glaucophane-bearing schists, indicating an advanced retrograde evolution within shear zones. Through the integration of thermodynamic modeling (P-T-M-H2O pseudosections), petrology, mineral chemistry, and reaction textures, a counterclockwise P-T path has been established for the area. The Tin Hallen metagabbros display a prominent granulitic imprint surrounding magmatic relicts in H2O-undersaturated conditions. This evolution reflects a pressure increase at nearly constant temperature, progressing from c. 6 kbar and c. 900 degrees C (M1) to 9-10.5 kbar and 850-900 degrees C (M2), likely linked to the thickening of the magmatic arc root, as suggested by other international studies. The granulitization is followed by further pressure increases and temperature decreases, leading to the mylonitic garnet amphibolite stage (M3) at similar to 14 kbar and 740 degrees C, along with a significant rise in M-H2O. Moreover, the presence of an original blueschist-facies stage (M4) with high-pressure, low-temperature (HP-LT) conditions (c. 8 kbar and 470 degrees C) is characteristic of cold subduction gradients (10-15 degrees C/km).
To reconstruct transmission chains of the multidrug-resistant tuberculosis Ch strain, which harbors a unique combination of resistance mutations, we analyzed genomes of 25 isolates from 12 patients with diagnosis during 2006-2022 in Chaco Province, Argentina. Amplification of resistance, high mortality rates, and indications of a wider outbreak raise concerns for surveillance programs.
