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Significant regions of Canada are seismically active, and areas underlain by loose, saturated sediments in these regions are expected to experience liquefaction-induced lateral spread permanent ground displacements (PGDs) under earthquake shaking. The empirical predictive equations are commonly used for estimating the PGDs especially when detailed numerical analyses are not undertaken. The key input parameters for these equations comprise earthquake magnitude (M) and source distance (R), along with geotechnical and topographic parameters; however, there is ambiguity over choosing appropriate site-specific values of M and R. The current study predicts PGD probabilistic hazard curves that are applicable for locations in southwestern and southeastern regions of Canada using a probabilistic seismic hazard assessment (PSHA) framework. This was achieved by embedding two relevant empirical models for predicting lateral spread PGDs (replacing the ground motion prediction equations) within the 2015 National Building Code of Canada framework that is currently available in OpenQuake platform. Moreover, deaggregation analyses have been performed to understand the M and R contributions from different seismic sources on the predicted site-specific hazard. The developed PGD curves can be readily adopted for estimating site-specific lateral spread PGD demand as input to performance-based design of structures in seismically active areas of Canada. Key words: liquefaction-induced lateral spread permanent ground displacements, probabilistic seismic hazard assessment (PSHA), empirical model, National Building Code of Canada (NBCC) 2015, OpenQuake, site-specific, hazard curves. De nombreuses regions du Canada sont actives sur le plan sismique, et les zones reposant sur des sediments laches et satures dans ces regions sont susceptibles de subir des deplacements permanents du sol (DPS) induits par la liquefaction lors de secousses sismiques. Les equations predictives empiriques sont couramment utilisees pour estimer les DPI, en particulier lorsque des analyses numeriques detaillees ne sont pas entreprises. Les principaux parametres d'entree de ces equations sont la magnitude du seisme (M) et la distance de la source (R), ainsi que les parametres geotechniques et topographiques; cependant, il existe une ambiguite quant au choix des valeurs appropriees de M et R pour chaque site. L'etude actuelle predit des courbes d'aleas probabilistes PGD qui sont applicables a des emplacements dans les regions du sud- ouest et du sud-est du Canada en utilisant un cadre d'evaluation probabiliste des risques sismiques (PSHA). Pour ce faire, nous avons integre deux modeles empiriques pertinents pour la prediction des DPI de propagation laterale (en remplacement des equations de prediction des mouvements du sol) dans le cadre du Code national du batiment du Canada 2015 qui est actuellement disponible dans la plateforme OpenQuake. En outre, des analyses de desagregation ont ete effectuees pour comprendre les contributions M et R des differentes sources sismiques sur les risques specifiques au site predits. Les courbes PGD developpees peuvent etre facilement adoptees pour l'estimation de la demande PGD de propagation laterale specifique au site comme donnee d'entree pour la conception basee sur la performance des structures dans les zones sismiques actives du Canada. [Traduit par la Redaction] Mots-cles : deplacements lateraux permanents du sol induit par la liquefaction, cadre d'evaluation probabiliste des risques sismiques (PSHA), modele empirique, Code national du bratiment du Canada (NBCC) 2015, OpenQuake, courbes de risque, specifiques au site., Introduction During past earthquakes, liquefaction-induced lateral spread displacements have resulted in failure of many buildings, bridges, transportation infrastructure, and pipelines. Extensive research has been conducted on the subject of estimating [...]

Paleomagnetism provides independent paleolatitude constraints on the India-Asia convergence. However, implied Cenozoic latitudinal convergence within Asia (thousands of km) largely exceeds geologic estimates of tectonic shortening (hundreds of km). This discrepancy may result from a notoriously low bias in paleomagnetically determined Cenozoic paleolatitudes in Asia. We provide here new paleomagnetic data from Cenozoic Mongolian volcanic rocks and from Chinese Paleogene sediments corrected from the depositional bias of inclination shallowing. These results combined with similar Asian data sets, confirm that paleolatitudes are still 5-10[degrees] lower than predicted by the paleomagnetic Apparent Polar Wander Path (APWP) for Asia between 50 and 20 Ma. Inclination-shallowing being excluded from the selected data sets, we investigate the likeliness of other proposed mechanisms for this discrepancy: (1) more southerly positions of Asia than expected by the APWP (due to APWP inaccuracies rather than Eurasian non-rigidity), or (2) non-dipolar geomagnetic field contributions. Fully explaining this discrepancy by only one of these mechanisms would imply either unrealistically large (>10[degrees]) APWP inaccuracies, or unrealistically large octupolar field contributions (up to 16%). A combination of these mechanisms is found more likely to have produced the observed latitudinal discrepancy, but their respective contributions cannot be quantified given the still relatively low amount and poor quality of Cenozoic paleomagnetic data from stable cratons of Asia, India, and Europe. By allowing for reasonable time-dependant non-dipolar contributions and a slight ( doi: 10.1029/2008TC002437.

The Parry Sound domain is a granulite nappestack transported cratonward during reactivation of the ductile lower and middle crust in the late convergence of the Mesoproterozoic Grenville orogeny. Field observations suggest the following with respect to the ductile sheath: (1) Formation of a carapace of transposed amphibolite facies gneiss derived from and enveloping the western extremity of the Parry Sound domain and separating it from high-strain gneiss of adjacent allochthons. This ductile sheath formed dynamically around the moving granulite nappe through the development of systems of progressively linked shear zones. (2) Transposition initiated by hydration (amphibolization) of granulite facies gneiss by introduction of fluid along cracks accompanying pegmatite emplacement. Shear zones nucleated along pegmatite margins and subsequently linked and rotated. The source of the pegmatites was most likely subjacent migmatitic and pegmatite-rich units or units over which Parry Sound domain was transported. Comparison of gneisses of the ductile sheath with high-strain layered gneiss of adjacent allochthons show the mode of transposition of penetratively layered gneiss depended on whether or not the gneiss protoliths were amphibolite or granulite facies tectonites before initiation of transposition, resulting in, e.g., folding before shearing, no folding before shearing, respectively. Meter-scale truncation along high-strain gradients at the margins of both types of transposition-related shear zones observed within and marginal to Parry Sound domain mimic features at kilometer scales, implying that apparent truncation by transposition originating in a manner similar to the ductile sheath may be a common feature of deep crustal ductile reworking. doi: 10.1029/2009TC002537.

Convergent margins with oblique subduction commonly include a fore-arc sliver, a portion of the overlying plate bounded by the trench and a major strike-slip fault system. It has long been noted that relative plate motion near the deformation front, as indicated by earthquake focal mechanisms, is generally closer to margin-normal than would be expected from overall relative plate motion. This results from sliver motion as well as from shear within the fore arc. We carry out some simple calculations to determine how the rate of sliver motion should vary with plate convergence obliquity. We find that the results are related to rheology but that the measurement of sliver rates at natural fore arcs is unlikely to yield real insight into physical properties; even for very simple models; the system is too complicated and its relation to rheology is not unique. The proportion of oblique convergence taken up by sliver motion in simple tabletop experiments depends on the rate of slip and the smoothing of asperities. Similarities in taper and style of strain between frontal wedges forming with and without slivers suggest that structural observations of exhumed accretionary wedges are unlikely to allow geologists to draw definitive conclusions about the degree of obliquity of relative plate motion at the time when the wedges were formed and in some cases not even whether or not a sliver plate was present at the time of deformation. doi: 10.1029/2009TC002583.

The eastern part of Mykonos island (Cyclades, Greece) shows the detailed internal structure of a two-branch shallow-dipping extensional detachment system of Miocene age. This paper shows that the last stage of slip along the detachment, during the deposition of syn-rift sediments, occurred with a very low dip and proposes that this geometry prevailed since the initiation of extension. Extensional deformation during and after a 13 Ma old granite intrusion is taken up by two main shallow-dipping shear zones: (1) The lower Livada detachment, which extends laterally across Tinos island, is a ductile structure located at the interface between the granite and the Upper Cycladic Nappe metabasites. A pervasive top-to-the-NE shearing deformation is observed throughout the granite in this island with a strong gradient toward the intrusive contact. Later brittle faults, shallowly and steeply dipping, rework the ductile deformation with the same overall shear sense. (2) The upper Mykonos detachment is brittle and separates the metabasites from late Miocene sandstones and conglomerates. The detachment fault dips 12-15[degrees] toward the NNE, and its sense of shear is consistent with that of the Livada detachment. Soft-sediment deformation during the time of detachment faulting and the presence of steep normal faults that root into the detachment gouge indicate a shallow depth of deformation. Rotations about vertical and horizontal axes can be reconstructed within and below the detachment zone, indicating that the overall direction of extension is NNE/SSW with a sense of shear toward the NNE and the dip of the fault is throughout very low. The two detachments have accommodated several tens of kilometers of horizontal extension during the formation of the Aegean Sea, which emphasizes the importance of low-angle extensional faults and shear zones in extensional tectonics. doi: 10.1029/2009TC002564.

A system of northwest striking Neoproterozoic rift basins underlies Paleozoic strata in the southern Georgina Basin of central Australia. Normal faults bounding these rift basins were selectively reactivated during the mid-Paleozoic Alice Springs Orogeny and are now expressed as high-angle reverse faults that invert the preexisting rift basins. Exhumed and eroded rift basin remnants are present in the hanging wall of the Oomoolmilla, Lucy Creek, Tarlton, and Toomba reverse faults, and rift basins may be preserved in the subsurface beneath the Toko Syncline and Burke River Structural Belt. Rift basin fill indicates two periods of extension: a major rift-forming episode between approximately 700 and 650 Ma (coeval with Sturtian glacial deposits) and a second episode of extension at approximately 600 Ma (coeval with Marinoan glacial deposits). This northwest striking rift system in central Australia supports results from other regions, indicating that the Neoproterozoic continental margin of Australia consisted of northwest striking rift segments offset by northeast striking transform faults. Such a configuration is geometrically incompatible with a Laurentian continental margin consisting of northeast striking rift segments and conflicts with reconstructions such as SWEAT and AUSWUS that match Australia with western Laurentia in the Rodinia supercontinent. doi: 10.1029/2009TC002543.

The Atlantic passive margin of Morocco developed during Mesozoic times in association with the opening of the Central Atlantic and the Alpine Tethys. Extensional basins formed along the future continental margin and in the Atlas rift system. In Alpine times, this system was inverted to form the High and Middle Atlas fold-and-thrust belts. To provide a quantitative kinematic analysis of the evolution of the rifted margin, we present a crustal section crossing the Atlantic margin in the region of the Doukkala Basin, the Meseta and the Atlas system. We construct a post-rift upper crustal section compensating for Tertiary to present vertical movements and horizontal deformations, and we conduct numerical modeling to test quantitative relations between amounts and distribution of thinning and related vertical movements. Rifting along the transect began in the Late Triassic and ended with the appearance of oceanic crust at 175 Ma. Subsidence, possibly related to crustal thinning, continued in the Atlas rift in the Middle Jurassic. The numerical models confirm that the margin experienced a polyphase rifting history. The lithosphere along the transect preserved some strength throughout rifting with the Effective Elastic Thickness corresponding to an isotherm of 450[degrees]C. A mid-crustal level of necking of 15 km characterized the pre-rift lithosphere. doi: 10.1029/2009TC002464.

Proper consideration of the uplift pressure at the base of a concrete gravity dam is of great importance in practical engineering, since it is crucial to the safety of the dam, specifically for a cracked dam under seismic conditions. However, constant uplift pressure, which is suitable for the static case only, was adopted in almost all the seismic analyses of cracked concrete gravity dams. To adequately estimate the seismic behavior of cracked concrete gravity dams, a seismic uplift pressure model is proposed for a penetrated crack. In this model, the amount and the distribution of the uplift pressure along the assumed rigid crack walls are determined by the earthquake acceleration, the water heads, the aperture of the crack, and the opening/closing velocity. Application of the model to a typical concrete gravity dam with a penetrated crack at the base reveals that the seismic behavior of the dam is markedly affected by the seismic uplift pressure. In general, the residual downstream sliding is considerably enlarged compared to that of constant uplift pressure. Computations show that the seismic uplift pressure can be several times higher than the constant one, increasing the dynamic instability of the cracked dam. It is also revealed that the dynamic water flow plays the role of a wedge while the upper mouth of the crack is closing. When the dam rocks back to upstream, the uplift pressure increases until it is so high that the pivot at the toe is raised up and the whole dam loses its contact. Then the resultant uplift pressure remains constant until the dam is inclined to the upstream. During this period of time, the cracked dam is normally drifting towards the downstream due to the hydro pressure. DOI: 10.1061/(ASCE)0733-9399(2008)134:11(991) CE Database subject headings: Dams, gravity; Seismic effects; Pressure; Cracking; Dam safety.

A new type of activation function, based on the use of the Prandtl-Ishlinskii operator, has been developed and used in the feed forward neural networks in order to improve their capabilities in learning to identify and analyze nonlinear structures subject to dynamic loading. The genetic algorithm has been used in its training. The neural network, which is referred to as the Prandtl neural network here, has been trained and used in the analysis of two shear frames, a single degree of freedom (SDOF) and a 3DOF, both subjected to earthquake excitations. To assess the capabilities of the Prandtl neural network under ideal situations, the data on the response of the frames have been obtained through the integration of their governing nonlinear equations of motion. The training has been based on the white noise while the strong earthquakes of 200% El Centro in 1940 and Gilroy have been used for testing. Results have shown the high precision of the Prandtl neural network in solving highly hysteretic problems. The issue is important for two main applications in structural dynamics and control: (1) analysis of highly nonlinear structures where it is desired to train a neural network to directly learn the behavior of a structure from experimental data; and (2) intelligent active control of structures where neural network emulators are designed to provide as precise predictions about the future response of the structures as possible, in order to be used in the determination of the required control forces. DOI: 10.1061/(ASCE)0733-9399(2008)134:11(961) CE Database subject headings: Neural networks; Algorithms; Nonlinear analysis; Hysteresis; Frames; Ground motion; Dynamic analysis.

Downhole ground motions recorded at the Lotung Large-Scale Seismic Test (LSST) site were used in this paper to infer in-situ dynamic soil properties. The purposes were (1) to provide field evidence of nonlinear soil behavior during earthquake excitation; and (2) to evaluate the accuracy of dynamic properties obtained from geophysical measurements and laboratory tests. For each horizontal component and event analyzed, representative shear-wave velocity and effective shear strain (defined as 65% of peak strain) between consecutive recording stations were estimated. The representative shear-wave velocities were estimated from fundamental resonant frequencies identifiable from the Fourier spectral ratios. The effective shear strains were estimated by linear ground response deconvolution analyses based on the inferred shear-wave velocity profiles. The inferred reduction in shear modulus with increasing effective shear strain was compared with laboratory test data. The degree of agreement between the inferred shear modulus reduction curves and the laboratory test data varied with different testing programs. The inferred low-strain shear-wave velocity profile agreed with geophysical measurements. These observations not only provide field evidence of nonlinear dynamic soil behavior during earthquakes, but also confirm the reasonableness of data provided by geophysical measurements and laboratory tests.

Galileo's proof of the motion of the earth from the motion of sunspots is discussed. It says that Galileo was not consistent and not even honest in his sunspots argument as he ignored the precession of the equinoxes.

Analysis of broadband teleseismic data shows that the 18 June 2000 Wharton Basin earthquake, a moment magnitude 7.8 intraplate event in the region of diffuse deformation separating the Indian and Australian plates, consisted of two subevents that simultaneously ruptured two near-conjugate planes. This mode of rupture accommodates shortening by a mechanism different from that previously known elsewhere in the region. The larger subevent occurred on a fossil fracture zone, with a relatively high stress drop of about 20 megapascals, showing that large stresses can accumulate in regions of distributed deformation., Plate motions in the Indian Ocean have been shown to be inconsistent with a rigid IndoAustralian plate (1). Additional diffuse boundaries splitting this plate into Indian, Australian, and Capricorn plates [...]

Results of seismological tests indicating that a piece of upper mantle that was missing for about 15 million years could have contributed to the great height of the Tibetan Plateau are presented.

The LightSAR (surface aperture radar) is an earth-imaging radar satellite that was proposed by NASA to monitor crustal deformation and geological events. The satellite will utilize SAR interferometry which was developed by Howard Zebker and his team at the Jet Propulsion Laboratory. SAR interferometry can detect crustal deformation under extreme weather conditions and produce three-dimensional images of the earth's crust. Furthermore, the SAR-imaging satellite will be utilized to monitor earthquakes, volcanic eruptions, forest growth and tectonic plate movement.