Determination of some trace elements in geochemical standards by X-ray fluorescence

The following trace elements Cr, Cu, Nb, Ni, Pb, Rb, Sr, Y, Zn, and Zr were determined by X-ray fluorescence in some geochemical standards from Japan and France. The internal standard method was applied using a Philips PW 1410 X-ray spectrometer. The results were compared with the published data.     

Gamma-Ray lines from the galaxy: the GRO revolution

The Compton Gamma-Ray Observatory (GRO) functioned flawlessly for more than8 years. Its accomplishments, both in novelty and breadth, have virtuallyrevolutionized the field of gamma-ray astrophysics. Since the review ofits entire palette of results would be outside the scope of the presentreview, we will limit ourselves to the sub-field of Galactic gamma-raylines; furthermore, we will have to neglect the minor topic of very-highenergy gamma-ray lines (pion decay, axion annihilation, etc.).This review is divided into three main parts, plus an introductionpresenting GRO and a summary in the form of a table showing the originalobjectives, GRO's accomplishments, and the remaining goals in eachsub-field. The first main part deals with the knowledge gained from longand extensive observations of the Galactic electron-positron annihilationline radiation; the second major section treats the Galactic lines fromradioactive isotope decay; the third major section discusses advances(and recent failures) in the very interesting field of Galactic nuclearde-excitation lines. In each case, an effort will be made not only topresent the current knowledge in the field, but to particularly highlightthe contribution made by GRO to our knowledge.     

Classification of daily solar irradiation by fractional analysis of 10-min-means of solar irradiance

Summary This paper deals with fractal analysis of daily solar irradiances measured with a time step of 10 minutes at Golden and Boulder located in Colorado. The aim is to estimate the fractal dimensions in order to perform classification of daily solar irradiances. The estimated fractal dimension and the clearness index KT are used as classification criteria. The results show that these criteria lead to three classes: clear sky, partially covered sky and overcast sky. The results also show that the evaluation of the fractal dimension of the irradiance signal based on a data set with 10 minutes time step is possible.     

The Laalam (Algeria) damaging landslide triggered by a moderate earthquake (M<Subscript>w</Subscript> = 5.2)

On March 20th, 2006, a moderate earthquake (M_w = 5.2) struck the Laalam (NE-Algeria). The damage was centred in the Laalam village where four deaths, 68 injured and more than 40 housing units destroyed making dozens of peoples homeless. Damage and casualties are directly related to an earthquake-induced landslide occurred at 10 km far from the epicenter (ISC relocation). The landslide rupture, mapped by using a ground based survey, is striking NE-SW along a 1-km length rupture with a 45 cm of lateral displacement. The rupture plan is dipping 40° at the surface and showing horizontal striations. A 75 cm of pre-2006 lateral displacement is also observed indicating a repetitive behaviour of the landslide. The last time where the landslide was activated extends back to 1974 following another moderate earthquake. This landslide reminds us the high level hazard of induced ground failures due slope instabilities in mountainous zones of seismically active areas.     

Field evidence of Quaternary seismites in the Mostaganem-Relizane (western Algeria) region: seismotectonic implication

Northwestern Algeria, Tell Atlas chain, belongs to the converging Africa-Eurasia plate boundary. Several active faults have been previously identified and several earthquakes occurred in the past. In the present study, seismites are observed in the Quaternary deposits. The identified seismites include injection sand dykes, pillar structures, pillow structures, load-cast structures, water escape structures, sismoslumps, thixotropic wedges, and thixotropic bowls. The following arguments support their seismic origin: (i) presence of active faults able of producing strong earthquakes, (ii) the granulometric characteristics of the deposits are favorable to liquefaction, (iii) the observed features, mainly those related to water escape structures, are comparable to those observed in modern earthquakes. Therefore, such features are evidence of the occurrence of earthquakes of M?>?5.5 magnitude in this study area, which may occur in the future.     

Seismic risk and damage prediction: case of the buildings in Constantine city (Algeria)

Located at the North-Eastern part of Algeria (Tellian Atlas), Constantine has crucial administrative, economic, scientific and cultural importance. It has continuously experienced significant urban evolutions during the different periods of its history. The city is located in an active seismic region within Algeria and has been struck in the past by several moderate and strong earthquakes. The strongest earthquake recorded since the beginning of instrumental seismology took place on October 27, 1985 with a magnitude M \(_\mathrm{S}=\) 5.9. Constantine presents a high seismic risk, because of its dense housing and high population density (2,374 inhabitants/km \(^{2})\) . This requires a risk assessment in order to take preventive measures and reduce the losses in case of potential major earthquake. For this purpose, a scenario based approach is considered. The building damage assessment methodology adopted for the Algerian context is adapted from HAZUS approach. In the present case, the effective Algerian seismic code response spectrum (RPA 99/2003) is considered as a seismic hazard model. The prediction of the expected damages is performed for a set of almost 29,000 buildings.     

Revisiting the Amati and Yonetoku correlations with Swift GRBs

We use a sample of Swift gamma-ray bursts (GRBs) to analyze the Amati and Yonetoku correlations. The first relation is between E _p,i , the intrinsic peak energy of the prompt GRB emission, and E _iso , the equivalent isotropic energy. The second relation is between E _p,i and L _iso , the isotropic peak luminosity. We select a sample of 71 Swift GRBs that have a measured redshift and whose observed $E^{obs}_{p}$ is within the interval of energy 15–150 keV with a relative uncertainty of less than 70 %. We seek to find correlation relations for long-duration GRBs (LGRBs) with a peak photon flux P _ph ≥2.6 ph/cm²/s. Uncertainties (error bars) on the values of the calculated energy flux P, the energy E _iso , and the peak isotropic luminosity L _iso are estimated using a Monte Carlo approach. We find 27 Swift LGRBs that satisfy all our constraints. Results of our analyses of the sample of 71 GRBs and the selected subsample (27 GRBs) are in good agreement with published results. The plots of the two relations for all bursts show a large dispersion around the best straight lines in the sample of 71 LGRBs but not so much in the subsample of 27 GRBs.