The Dinar Earthquake (Mw = 6.2; October 1, 1995; Afyon-Turkey) and Earthquake Hazard of the Dinar-Çivril Fault

—A moderately strong earthquake (M _w = 6.2) occurred in the town of Dinar at 17.57 UT on October 1, 1995, taking the lives of 90 people and damaging about 4500 buildings. Its epicenter is located near the Dinar-Çivril fault and its focal mechanism is linked to a northeast-southwesterly tensional stress field arising from the interaction between the subducting African plate and the overriding Aegean-Anatolian plate in the eastern Mediterranean.¶Surface cracks of the October 1 earthquake have been observed 10 km continuously along the Dinar-Çivril fault. The cracks have displayed a mode of dip-slip; however, some have also indicated lateral slip. The different modes of slip are generally in agreement with the fault plane solution and are indicators of the complex nature of the rupture process.¶In investigating the earthquake hazard of the Dinar-Çivril fault and proximity, the maximum likelihood method was used to estimate seismic hazard parameters of b-value, seismicity activity rate λ _m and the expected maximum magnitude M _max?. The data consisted of the historical data covering the period between 1800–1900 and instrumental data between 1900 and 1992. This method, allowing use of the mixed earthquake catalogue containing both historical and instrumental earthquake data, yielded values of 0.70, 1.92 and 7.14 for b, λ _m and M _max?, respectively. The recurrence time estimated for an earthquake of a magnitude of M _w = 6.2 is 123 years. The non-occurrence probabilities of such an earthquake in 1 and 50 years are 0.21 and 0.04, respectively.     

Magnetic properties of monodomain aluminium-substituted titanomagnetite

A suite of synthetic titanomagnetites were prepared with compositions Fe_2.6?δTi_0.4Al_δO₄ and Fe_2.4?δTi_0.6Al_δO₄ (δ = 0, 0.1, 0.2 in both cases). Ball-milling of the synthesized samples produced material in the magnetic monodomain state as indicated by hysteresis loops and the Lowrie-Fuller test. The coercive force of the specimens depends on the Al concentration and lies in the range 1–2 kOe. The TRM induced in the samples is correspondingly “hard”. The low-field (0–1 Oe) TRM acquisition curve is linear. The higher field TRM-H curve is not in agreement with either monodomain or two-domain theoretical models.     

The dispersion of surface waves and crustal structure in African continent

Summary In this study has been interpreted the Love- and Rayleigh-waves of Agadir earthquake on February 29, 1960 recorded at Lwiro and Skopje earthquake on July 26, 1963 recorded at Pretoria and Windhoek by long period Columbia type seismographs, and determined the crustal structure in Africa with dispersion of both Love- and Rayleigh-waves along the paths on two different directions. The obtained results are compared each other and with those founded recently by several investigators for Africa and Europe. Herewith has been showed that the average thickness of the crust in Africa is thinner than in Europe and the thickness in direction from Skopje to Pretoria is more than that from Agadir to Lwiro.

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Zusammenfassung In diesem Artikel wurden die Love- und Rayleigh-Wellen vom Erdbeben in Agadir vom 29. Februar 1960, aufgezeichnet in Lwiro, und vom Erdbeben in Skopje vom 26. Juli 1963, aufgezeichnet in Pretoria und Windhoek von langperiodischen Columbia-Seismographen, untersucht und somit mit Dispersion von beiden Love- und Rayleigh-Wellen der Aufbau der Erdkruste in Afrika bestimmt. Die erhaltenen Resultate wurden miteinander und mit anderen Werten, die bis heute von verschiedenen Autoren für Afrika und Europa bestimmt wurden, verglichen. Somit wurde vorgelegt, dass die Erdkruste in Afrika im allgemeinen dünner ist als in Europa und dass die Schicht in der Richtung von Skopje zu Pretoria dicker ist als in der Richtung von Agadir zu Lwiro.

     

Microbial transport in soils and groundwater: A numerical model

To serve as a tool in the long term evaluation of the risk of accumulation of microbial contaminants (bacteria and viruses) entering soil and groundwater, a mathematical model is developed to predict the spatial and temporal distribution of pollutant concentration. The governing equation for bacterial transport is coupled with a transport equation for the bacterial nutrient present in the seeping wastewater. The deposition and declogging mechanisms are incorporated into the model as a rate process for bacteria and as an equilibrium partitioning for viruses. While the decay is assumed to be a first order reaction and the growth of bacteria is assumed to follow the Monod equation, the model equations exhibit nonlinearity and coupling. A simplified set of equations is solved analytically to test the numerical results. Coupled numerical solutions in one and two dimensions are obtained by the Galerkin method at spatial and temporal locations of interest. Cases studied included a soil column and a horizontal two-dimensional field coupled with the one dimensional solution. For these examples, the bacteria are removed almost totally within the top 7 cm of soil with minimal risk of clogging.     

Geochemistry of Proterozoic molybdenite — mineralized aplites in Northern Sweden

The largest known Precambrian molybdenite occurrences in Sweden are of the aplitic type. In order to improve the understanding of their genesis, 67 samples of aplites, aplitic granites and associated granites were analyzed for major elements, Mo, Sn, Be, Ba, Rb, Sr, Cu, Zn, Zr, V, Cr, Ni, Y, Nb, F, Cl and S. Five samples were analyzed for rare earth elements. The following genetic model can be proposed:In the upper parts of granitic intrusions the magma is enriched in lithophile elements and elements such as F and Mo. The aplites represent direct differentiation products of the granites and have solidified without the development of a second mobile aqueous phase, except locally, where small pegmatite segregations have formed. As crystallization proceeds, the concentration of Mo in the magma increases, and when the aplites solidify, the Mo that cannot be incorporated in the rock-forming minerals is precipitated as molybdenite. Biotite seems to be the major Mo-carrier among the rock-forming minerals in the aplites.     

Geosecs North Atlantic radiocarbon and tritium results

Radiocarbon data for 11 stations and tritium data for 16 stations in the North Atlantic Ocean from 74°N to 3°N are presented. For radiocarbon, normal errors inΔ¹⁴C are± 4‰, and in tritium,± 0.09TU or± 3%, whichever is larger. There is a remarkable, but not simply linear, correlation between oceanic bomb transients in¹⁴C and³H. The deep convective mixing in the Greenland Sea is reflected in substantial bomb tracer penetration to all depths, with residence time for the deep, cold core water that seems to be 20 to 30 years. The outflow in the bottom layer southward over the sills of the Denmark Strait and Faroe Passage carries significant tritium concentration, at least to 40°N. Complicated, but coherent, profile structures in the subtropical Atlantic suggest effects of large-scale lateral advection. In particular, a pronounced minimum in both¹⁴C and³H might be associated with the Antarctic intermediate water.     

Seismic hazard studies for Gaziantep city in South Anatolia of Turkey

Seismic hazard studies were conducted for Gaziantep city in the South Anatolia of Turkey. For this purpose, a new attenuation relationship was developed using the data of Zaré and Bard and accelerations were predicted employing this new equation. Deterministic approach, total probability theorem and GIS methodology were all together utilized for the seismic assessments. Seismic hazard maps with 0.25° grid intervals considering the site conditions were produced by the GIS technique. The results indicated that the acceleration values by the GIS hazard modelings were matched with the ones from the deterministic approach, however, they were underestimated comparing with the total probability theorem. In addition, the GIS based seismic hazard maps showed that the current seismic map of Turkey fairly yields conservative acceleration values for the Gaziantep region. Therefore, the constructed GIS hazard models are offered as a base map for a further modification of the current seismic hazard map.     

Biodegradation effects over different types of coastal rocks

Modern coastal areas have natural and transported rocks (armourstone) on which various types of organisms live. Burrowing, boring and feeding by these organisms can destroy or modify the coastal rocks and hence change the coastal morphology. Two rock types and three dominant types of organisms have been studied in Mersin Bay, Eastern Mediterranean of southern Turkey. In this study area, Plio-Quaternary conglomerates and variously aged limestone armourplates have been affected by Phoronida worms, bivalve Brachidontes pharaonis (Fischer P. 1870) and the limpet Patella sp. Phoronida colonies were found covering the hard substratum as a mat and form tubular endolithes of 35.0 mm depth and 1.5 mm diameter, whilst Brachidontes pharaonis (Fischer P. 1870) form 44 mm deep vase-shaped gastrochaenolites. The bioerosive activity of Limpet Patella sp., found intertidal and within the spray zone, cannot be significantly observed on the rocks over short time periods. The soft sandy matrix of the conglomerates present were found to disintegrate by bioerosional processes, with the released gravels being transported and deposited onto the beach. Within the armourstone limestone blocks, a maximum of 44.0 mm deep holes developed after 50–60 years. However, these biological activities do not threaten the stability of the blocks due to their hard and homogeneous internal structure. Furthermore, the organism colonies that cover these rocks as a strong mat (maximum 29.0 mm) act to protect their surfaces from further biological attack and wave action.