Seismic Hazard Assessment and Its Uncertainty for the Central Part of Northern Algeria

This study presents a probabilistic seismic hazard assessment for the central part of northern Algeria using two complementary seismic models: a fault-based model and a gridded seismicity model. Two ground-motion attenuation equations were chosen using the Pacific Earthquake Engineering Research Center Next-Generation models, as well as local and regional ones. The ranking method was used to assess their ability to gather accurate data. To account for epistemic uncertainty in both components of the assessment, the seismic hazard was computed using a logic tree approach. Expert judgment and data testing were used to evaluate the weights assigned to individual ground-motion prediction equations. The seismic hazard maps depicted the obtained results in terms of spectral accelerations at oscillation periods of 0.0, 0.2, and 1.0 s, with 10% and 5% probabilities of exceedance in 50 years, and for soil types B, B/C, C, and C/D, as defined by the National Earthquake Hazards Reduction Program. From the analysis, the uncertainty is expressed as both a 95% confidence band and the coefficient of variation (COV). Annual frequencies of exceedance and hazard curves were estimated for the selected cities, as well as uniform hazard spectra for the previously quoted probabilities of exceedance and the soil types considered. Peak ground acceleration values of 0.44±0.17 g and 0.38±0.06 g were reported for the B/C soil type in the cities of Algiers and Blida, respectively, for a return period of 475 years. Seismic maps for the selected return periods depicting the classification of the estimated values are also displayed in terms of very high, high, medium, low and very low degrees of reliability. Furthermore, a seismic hazard disaggregation analysis in terms of magnitude, distance, and azimuth was carried out. The primary goal of such analyses is to determine the relative contribution of different seismic foci and sources to seismic hazard at specific locations. Thus, for each studied city, for the considered return periods and for the soil type B/C, the so-called control or modal earthquake was estimated. At Algiers, events with magnitudes Mw 5.0–5.5 and distances of less than 10 km contribute the most to the mean seismic hazard over a 475-year period. However, for the same return period, those events with Mw 7.0–7.5 and located between 10 and 20 km away contribute the most to the seismic hazard at Tipaza

Comparative genome analysis of Bacillus spp. and its relationship with bioactive nonribosomal peptide production

Bacillus genus comprises an important number of species which produce a wide range of secondary metabolites displaying a broad spectrum of activity and great structural diversity. The genome sequences of an important number of species have been published and a large number of orphan genes reported. This review, covering all the literature in this field up to end of 2011, summarizes and compares the genetic potential of these organisms from the point of view of bioactive nonribosomal peptide production and their application as antibiotics, plant pathogen biocontrol, promotion of plant growth, etc. The biological and structural studies of the peptides isolated from Bacillus species are revised and some aspects of the biosynthesis of these metabolites and related compounds are discussed

Earthquake Magnitude and Frequency Forecasting in Northeastern Algeria using Time Series Analysis

This study uses two different time series forecasting approaches (parametric and non-parametric) to assess a frequency and magnitude forecasting of earthquakes above Mw 4.0 in Northeastern Algeria. The Autoregressive Integrated Moving Average (ARIMA) model encompasses the parametric approach, while the non-parametric method employs the Singular Spectrum Analysis (SSA) approach. The ARIMA and SSA models were then used to train and forecast the annual number of earthquakes and annual maximum magnitude events occurring in Northeastern Algeria between 1910 and 2019, including 287 main events larger than Mw 4.0. The SSA method is used as a forecasting algorithm in this case, and the results are compared to those obtained by the ARIMA model. Based on the root mean square error (RMSE) criterion, the SSA forecasting model appears to be more appropriate than the ARIMA model. The consistency between the observation and the forecast is analyzed using a statistical test in terms of the total number of events, denoted as N-test. As a result, the findings indicate that the annual maximum magnitude in Northeastern Algeria between 2020 and 2030 will range from Mw 4.8 to Mw 5.1, while between four and six events with a magnitude of at least Mw 4.0 will occur annually

Global Newtonian limit for the Relativistic Boltzmann Equation near Vacuum

We study the Cauchy Problem for the relativistic Boltzmann equation with near Vacuum initial data. Unique global in time "mild" solutions are obtained uniformly in the speed of light parameter $c \ge 1$. We furthermore prove that solutions to the relativistic Boltzmann equation converge to solutions of the Newtonian Boltzmann equation in the limit as $c\to\infty$ on arbitrary time intervals $[0,T]$, with convergence rate $1/c^{2-\epsilon}$ for any $\epsilon \in(0,2)$. This may be the first proof of unique global in time validity of the Newtonian limit for a Kinetic equation.Comment: 35 page

Distributional and classical solutions to the Cauchy Boltzmann problem for soft potentials with integrable angular cross section

This paper focuses on the study of existence and uniqueness of distributional and classical solutions to the Cauchy Boltzmann problem for the soft potential case assuming $S^{n-1}$ integrability of the angular part of the collision kernel (Grad cut-off assumption). For this purpose we revisit the Kaniel--Shinbrot iteration technique to present an elementary proof of existence and uniqueness results that includes large data near a local Maxwellian regime with possibly infinite initial mass. We study the propagation of regularity using a recent estimate for the positive collision operator given in [3], by E. Carneiro and the authors, that permits to study such propagation without additional conditions on the collision kernel. Finally, an $L^{p}$-stability result (with $1\leq p\leq\infty$) is presented assuming the aforementioned condition.Comment: 19 page