ALBERT

Notes: SUMMARY— Comparisons involving fresh versus frozen chops and roasts from 190 lamb carcasses indicated significant though nonconformable treatment effects on cooked-sample palatability characteristics. Freezing resulted in a highly significant increase in shear force values for loin chops and highly significant decreases in flavor, tenderness and overall satisfaction scores for leg roasts. Freezing rib chops, in contrast to the results for loin chops and leg roasts, resulted in a highly significant decrease in shear force values indicating an increase in tenderness as the result of freezing. Several possible explanations concerning these contradictory findings are suggested and discussed. In other paired-chop comparisons, higher final cooking temperatures resulted in increased shear force values for rib chops; wrapping samples prior to freezing appeared to have little effect on chop tenderness comparisons. In all comparisons, variance ratios between chops treated differently were not significantly altered.

Notes: SUMMARY: Data collected from 690 beef rib steaks were utilized to evaluate the methodology of beef tenderness measurements. The information obtained in this study was critically compared to existing research and evaluated in relation to sample handling procedures. Frozen storage of steaks, especially if they are unprotected from dehydration or are stored for long periods of time, has important implications if such data are to be compared to steaks which were evaluated in the unfrozen state. Cooking frozen steaks with or without thawing apparently has little effect on tenderness or cooking loss. Anatomical location of the sample should be carefully controlled to prevent spurious differences from affecting tenderness measurements. Evidence indicates that a tenderness gradient exists over the cross-section of the I. dorsi and suggests that core samples should be taken from as many and as varied positions as is feasible for existing research conditions. The use of marbling score as an indicator of the tenderness of beef rib steaks resulted in the explanation of 28 percent of the variation in average shear force requirements. The shear force value of the diaphragm muscle was only moderately related (r = 0.40) to that of the I. dorsi. Cooking loss percentages were significantly increased as a result of freezing at–34°C and storage of steaks unwrapped at −23°C when compared to unfrozen steaks and by selecting I. dorsi samples from more anterior locations in the wholesale rib.

Notes: We present geological and morphological observations at different scales to constrain rates of faulting and the distribution of deformation in the seismically active Aegean region. We focus first on the 130 km long Corinth Rift, an asymmetric graben where a flight of terraces of marine origin are uplifted. We show that the edges of the terraces lie in the footwall of the normal fault bounding the Corinth Rift and correspond to sea-level highstands of laic Pleistocene age. Using a detailed analysis of aerial and SPOT imagery supported by field observations, we have mapped 10 terrace platforms and strandlines ranging in elevation from 10 to 400 m over distances of 2 to 20 km from the fault. The elevation of the terraces' inner edges was estimated at 172 sites with an error of ±5m. This data set contains a precise description of the uplift and flexure of 10 different palaeohorizontal lines with respect to the present sea level. To date the deformation, we correlate the Corinth terraces with late Pleistocene oxygen-isotope stages of high sea-level stands and with global sea-level fluctuations. Using a thick elastic plate model consistent with our current understanding of the earthquake cycle and a boundary-element technique we reproduce the geometry of the shorelines to constrain both mechanical parameters and the slip on the fault. We show that the seismogenic layer behaves over the long term as if its elastic modulus were reduced by a factor of about 1000. All the terraces are fitted for fault slip increasing in proportion to terrace age, and the component of regional uplift is found to be less than 0.3 mm yr−1. The best fits give a slip rate of 11±3 mm yr−1 on the main rift-bounding fault over the last 350 kyr. Other geological and morphologic information allows us to estimate the total age of the main fault (∼1 Ma) and to examine the mechanical evolution of the Corinth Rift. The minimum observed sediment thickness in the Gulf places an extreme check on the results of the modelling and a lower bound on slip rate of 6–7 mm yr−1 (40 per cent less than estimated with modelling). Even this slip rate is nearly 10 times higher than for comparable features in most of the Aegean and elsewhere in the world.At a larger scale, the spacing and asymmetry of the rift systems in the Aegean suggest strain localization in the upper mantle, with slow extension starting 15 Myr ago or earlier. The more recent (1 Myr), rapid phase of rifting in Corinth partly reactivated this earlier phase of extension. The younger faulting in Corinth appears to result from its present location in the inhomogeneous stress field (process zone) of the south-westward propagating tip of the southern branch of the North Anatolian Fault. We extend these relations to propose a mechanical model for the Late Cenozoic evolution of the Aegean. As the Arabia/Europe collision progressed in eastern Turkey it caused Anatolia to move to the west and the North Anatolian Fault to propagate into the Aegean, where the early slow extension started to be modified about 5 Ma ago. The process of propagation dramatically increased the activity of some but not all of the earlier rifts. The model we present is compatible with tectonic observations, as well as with the seismicity, the palaeomagnetic rotations and the displacement field now observed with GPS and SLR.

Notes: The El Asnam (Algeria) earthquake of 1980 October is the largest earthquake to have occurred in North Africa since instrumental records began (Ms = 7.3). It was caused by movement on a segmented reverse fault which is part of the fault zone that separates the Chelif alluvial plains from the coastal range of the Atlas Mountains. The coastal range is the actively deforming plate boundary between Africa and Eurasia.In this paper, the results of an aftershock study carried out using a 28-station portable network in the epicentral area in the 5 weeks after the main shock are presented. A total of 4517 aftershocks have been located, using both P- and S-phases. Of these 4517 events, 1279 pass a set of quality criteria, and are used to discuss the detailed tectonics of the aftershock zone.The southwestern half of the aftershock zone has a relatively restricted band of seismicity running parallel to the main fault. In cross-section, this seismicity is observed to lie almost exclusively in the footwall of the main fault, and indicates both antithetic reverse faulting and extension parallel to the fault zone. The only exception to this pattern occurs at a junction of the main fault segments, where a distinct cluster of events with very variable focal mechanisms is located in the hangingwall. This cluster may be equated with a barrier that impeded the rupture of the main shock. Beyond the southwest end of the main fault, a mixture of strike-slip and reverse faulting occurred, and suggests a mechanism whereby this end of the fault can act as an asperity for earthquake generation.Aftershocks in the northeastern half of the study area indicate movement on a stack of listric reverse faults. The focal mechanisms of these events show that the N-dipping nodal planes (assumed to be the fault planes) flatten with depth. We suggest that the faults sole into a low-angle (20°) decollement at about 8-10 km depth, at the base of the aftershock zone.We argue that the northeastern part of the 1980 aftershock zone is typical of the actively deforming coastal belt of northwest Algeria. Subduction of the western Mediterranean basin beneath the north African margin does not seem to occur. Instead, the margin is absorbing the motion, with old normal faults being reactivated as thrusts.