shallow fault zone dilatancy recovery after the 2003 bam earthquake in iran earthquakes radiate from slip on discrete faults but also commonly involve distributed deformation within a broader fault zone especially near the surface variations in rock strain during an earthquake are caused by heterogeneity in the elastic stress before the earthquake by variable material properties and geometry of the fault zones and by dynamic processes during the rupture stress changes due to the earthquake slip both dynamic and static have long been thought to cause dilatancy in the fault zone that recovers after the earthquake decreases in the velocity of seismic waves passing through the fault zone due to coseismic dilatancy have been observed followed by postseismic seismic velocity increases during healing dilatancy and its recovery have not previously been observed geodetically here we use interferometric analysis of synthetic aperture radar images to measure postseismic surface deformation after the 2003 bam iran earthquake and show reversal of coseismic dilatancy in the shallow fault zone that causes subsidence of the surface this compaction of the fault zone is directly above the patch of greatest coseismic slip at depth the dilatancy and compaction probably reflects distributed shear and damage to the material during the earthquake that heals afterwards coseismic and postseismic deformation spread through a fault zone volume may resolve the paradox of shallow slip deficits for some strike slip fault ruptures

wave dispersion study for tsunami propagation in the sea of marmara in this paper the aim is to investigate whether there are differences between the dispersion and non dispersion solutions on tsunami propagation for this purpose two numerical models of tsunami propagation are compared one of these numerical models is a nondispersive model that uses saint venant equations and the other is a dispersive model that uses boussinesq equations the tsunamis resulting from a submarine mass failure smf which is settled at the bottom of the north eastern sea of marmara are examined an analytical solution considering wave dispersion is developed for obtaining near field tsunami amplitudes above the submarine mass failure numerical modeling is used at the sea surface from the common boundary called as liquid boundary with incident waves up to the coastal regions to get the tsunami amplitudes the output of the analytical model is taken as the disturbances for the numerical method in the numerical solutions telemac 2d software system is used for both dispersive and nondispersive modeling the results of the dispersive and nondispersive models are compared to each other both temporal and spatial differences in the amplitudes and wave shapes are examined the obtained results demonstrate that there are no noticeable differences between the dispersion and non dispersion solutions except some special cases and some special landslide velocities

slow spreading of a sheet of bingham fluid on an inclined plane to study the dynamics of fluid mud with a high concentration of cohesive clay particles we present a theory for a thin sheet of bingham plastic fluid flowing slowly on an inclined plane the physics is discussed on the approximate basis of the lubrication theory because of the yield stress the free surface need not be horizontal when the bingham fluid is in static equilibrium nor parallel to the plane bed when in steady flow we then show that there is a variety of gravity currents that can advance at a constant speed and with the same profile experimental confirmation of one type is presented by solving a nonlinear partial differential equation transient flows due either to a steady upstream discharge or to the sudden release of a finite fluid mass on another fluid layer are studied in the first case there is a mud front which ultimately propagates as a constant speed as a steady gravity current in the second case when the ambient layer is sufficiently shallow that there is no initial motion the flow induced by the new fluid can terminate after the disturbance has travelled a finite distance the extent of the final spread is examined disturbances due to an external pressure travelling parallel to the free surface are also examined it is found in particular that a travelling localized pulse of pressure gradient not only generates a localized mud disturbance which travels along with the forcing pressure but further leaves behind a permanent footprint

large scale low frequency response on the continental shelf due to localized atmospheric forcing systems abstract the first order wave equation model of gill and schumann which describes the flow induced on the continental shelf by the longshore wind stress evaluated at the coast is extended in three ways first we relax the nondivergent approximation and hence are able to estimate the response in the kelvin wave mode second we include the full wind stress forcing and allow for an offshore variation in the wind stress we also include a representation of pressure forcing thus we are able to describe the response due to localized forcing systems third we consider the coupling of the deep ocean region to the shelf region across a continental slope region modeled as a discontinuity in depth at the shelf break the results are applied to the response on the shelf due to a localized forcing system either traveling longshore parallel to the coast or traveling offshore normal to the coast

time dependent hydrodynamic models of turbidity currents analyzed with data from the grand banks and orleansville events abstract here we examine the motion of large catastrophic turbidity flows such as the grand banks event a brief review of the general theory for such phenomena is given two special cases of the general theory are applied to the grand banks and orleansville flows both cases are time dependent thus permitting calculation of the origin of the flow the models differ fundamentally in the parameterization of the hydrodynamic drag moving through the water at the sea floor nevertheless application of both models to the grand banks turbidity flow yields good agreement on the origin of this event the new origin is much lower on the slope than others have assumed and is consistent with plots of earthquake epicenters given a sufficiently dramatic initiating event such as an earthquake our results suggest that turbidity currents can be generated on slopes of less than 1 and accelerate within minutes to a maximum velocity of between 20 and 25 m sec

active deformation within the zagros mountains deduced from gps measurements we present and interpret the results of global positioning system gps measurements at 35 stations in and beside the zagros mountain belt sw iran for three campaigns ending march 1998 december 1999 and june 2001 preliminary motion estimates show clearly the change in character along the strike of the belt stations to the se move at 13 22 3 mm a 1 towards n 7 5 e with respect to eurasia most of the shortening indicated by the gps velocities seems to occur in the se zagros along two major seismic zones and along the zagros front to the nw stations move oblique to the trend of the belt towards n 12 8 w at 14 19 3 mm a 1 most of the shortening in the nw zagros seems to occur along the mountain front fault with its major earthquakes as well as along the zagros front the change in direction and magnitude of the velocity vectors across the north south trending kazerun and karebas faults involves extension of up to 4 mm a 1 along the strike of the zagros belt

some insight on why bam iran was destroyed by an earthquake of relatively moderate size 1 the bam iran earthquake of 2003 resulted in one of the worst human disaster in recent years yet the magnitude of the event mw 6 6 was relatively moderate we show that the remarkable recording of the ground motion produced in the city itself contains some clues which help explain this disaster we identify three factors whose unfortunate combination led to the strong ground shaking which destroyed the city 1 the rayleigh like speed of the rupture 2 the high slip velocity which exceeded 2m s over a large part of the fault 3 the strong directivity which focused the elastic energy released directly toward the city

numerical simulation of waves generated by landslides using a multiple fluid navier stokes model abstract this work reports on the application and experimental validation for idealized geometries of a multiple fluid navier stokes model of waves generated by rigid and deforming slides with the purpose of improving predictive simulations of landslide tsunamis in such simulations the computational domain is divided into water air and slide regions all treated as newtonian fluids for rigid slides a penalty method allows for parts of the fluid domain to behave as a solid with the latter method the coupling between a rigid slide and water is implicitly computed rather than specifying a known slide kinematics two different volume of fluid algorithms are tested for tracking interfaces between actual fluid regions the simulated kinematics of a semi elliptical block moving down a water covered plane slope is first compared to an earlier analytical solution results for the vertical fall of a rectangular block in water are then compared to earlier experimental results finally more realistic simulations of two and three dimensional wedges sliding down an incline are compared to earlier experiments overall in all cases solid block velocities and free surface deformations are accurately reproduced in the model provided that a sufficiently resolved discretization is used the potential of the model is then illustrated on more complex scenarios involving waves caused by multi block or deformable slides

domain reduction method for three dimensional earthquake modeling in localized regions part i theory this article reports on the development of a modular two step finite element methodology for modeling earthquake ground motion in highly heteroge neous localized regions with large contrasts in wavelengths we target complex geo logical structures such as sedimentary basins and ridges that are some distance away from the earthquake source we overcome the problem of multiple physical scales by subdividing the original problem into two simpler ones the first is an auxiliary problem that simulates the earthquake source and propagation path effects with a model that encompasses the source and a background structure from which the lo calized feature has been removed the second problem models local site effects its input is a set of equivalent localized forces derived from the first step these forces act only within a single layer of elements adjacent to the interface between the exterior region and the geological feature of interest this enables us to reduce the domain size in the second step if the background subsurface structure is simple one can replace the finite element method in the first step with an alternative efficient method the methodology is illustrated in a companion paper yoshimura et al 2003 for several 3d problems of increasing physical and computational complexity we consider first a flat layered stratigraphic system for this simple case the first step can be carried out by means of 3d green s function evaluations the extension to more general problems is illustrated by two examples a basin and a hill with the same background stratigraphy to verify the two step procedure with a problem for which the finite element method is used throughout we model ground motion in a small region of the los angeles basin using both the two step domain reduction method and the traditional approach in which the computational domain contains both the source and the geological region of interest

a perturbation solution for bingham plastic mudflows an analytical solution is proposed for laminar mudflows and debris flows that can be modeled by a bingham plastic law two dimensional unsteady nonuniform bingham flows released from a point source or a source of finite size dam break problem or mudslide problem on a steep slope are considered the method of matched asymptotic expansions was implemented to get a first order solution for the dam break problem the proposed model is found to be valid when the shock wave has advanced three reservoir lengths downstream also it is found that the bingham flow only propagates a finite distance downstream with the shock depth asymptotically approaching the yield depth and the shock velocity asymptotically falling to zero the hydrograph produced by a bingham flow is seen to have a slower and lower flood peak and a longer and higher flow tail than that produced by newtonian flow having the same dynamic viscosity comparison of the model predictions with laboratory observations shows reasonable agreement

methane bubble growth in fine grained muddy aquatic sediment insight from modeling abstract methane ch 4 is the most abundant hydrocarbon and one of the most important greenhouse gases in the atmosphere ch 4 bubble growth and migration within muddy aquatic sediments are closely associated with sediment fracturing in this paper we present the modeling of buoyancy driven ch 4 bubble growth in fine grained muddy aquatic sediment prior to the beginning of its rise we designed a coupled mechanical reaction transport numerical model that enables a differential fracturing over the bubble front as it occurs in nature when the fracturing increment stays constant at the bubble head and subsides towards bubble tail during bubble growth we show that this differential fracturing over the bubble front controls the bubble shape and size temporal evolution and is significantly affected by the critical stress intensity factor of the muddy sediment the intercalated stages of elastic expansion and fracturing during the bubble growth shorten with time as the bubble approaches its terminal size prior to its ascent our simulations reveal a high asymmetry in the bubble shape growing with time with respect to its initial symmetric penny shaped configuration it was found that the bubble grows allometrically while the importance of the bubble surface area growth with time we also confirmed the earlier predictions about the inverted tear drop bubble cross section just prior to the beginning of its rise modeling of the terminal bubble characteristics will permit prediction of the delivery of gaseous methane from the sediment to the atmosphere via the water column

surface displacements and source parameters of the 2003 bam iran earthquake from envisat advanced synthetic aperture radar imagery 1 the mw 6 6 26 december 2003 bam iran earthquake was one of the first earthquakes for which envisat advanced synthetic aperture radar asar data were available using interferograms and azimuth offsets from ascending and descending tracks we construct a three dimensional displacement field of the deformation due to the earthquake elastic dislocation modeling shows that the observed deformation pattern cannot be explained by slip on a single planar fault which significantly underestimates eastward and upward motions se of bam we find that the deformation pattern observed can be best explained by slip on two subparallel faults eighty five percent of moment release occurred on a previously unknown strike slip fault running into the center of bam with peak slip of over 2 m occurring at a depth of 5 km the remainder occurred as a combination of strike slip and thrusting motion on a southward extension of the previously mapped bam fault 5 km to the east

3 d velocity structure of the 2003 bam earthquake area se iran existence of a low poisson s ratio layer and its relation to heavy damage abstract to understand the generation mechanism of the bam earthquake mw 6 6 we studied three dimensional v p v s and poisson s ratio structures in the bam area by using the seismic tomography method we inverted accurate arrival times of 19490 p waves and 19015 s waves from 2396 aftershocks recorded by a temporal high sensitivity seismic network the 3 d velocity structure of the seismogenic region was well resolved to a depth of 14 km with significant velocity variations of up to 5 the general pattern of aftershock distribution was relocated by using the 3 d structure to delineate a source fault for a length of approximately 20 km along a line 4 5 km west of the known geological bam fault this source fault dips steeply westward and strikes a nearly north south line the main shallow cluster of aftershocks south of the city of bam is distributed just under the minor surface ruptures in the desert the 3 d velocity structure shows a thick layer of high v s and low minimum 0 20 at a depth range of 2 6 km the deeper layer with a thickness of about 2 km appears to have a low v s and high maximum 0 28 from 6 km depth beneath bam to a depth of 9 km south of the city the inferred increase of poisson s ratio from 2 to 10 km in depth may be associated with a change from rigid and sio 2 rich rock to more mafic rock including the probable existence of fluids the main seismic gap of aftershock distribution at the depth range of 2 to 7 km coincides well with the large slip zone in the shallow thick layer of high v s and low the large slip propagating mainly in the shallow rigid layer may be one of the main reasons why the bam area suffered heavy damage

numerical modeling of an underwater bingham plastic mudslide and the waves which it generates underwater landslides are a common source of tsunamis in coastal areas theoretical and experimental studies on this problem however are scarce because of the difficulties in modeling and observing a submarine slide and the associated tsunami to study this problem we present a numerical model that simulates the coupling of a bingham plastic mudslide on a gentle uniform slope with the surface waves which it generates a formulation of the dynamics of the problem is presented where the landslide is treated as an incompressible bingham plastic flow and the water motion is assumed irrotational the long wave approximation is adopted for both water waves and the mudslide dispersion of waves and potential turbulent mixing are not considered the resulting differential equations are solved by a finite difference method we present the numerical results for successive profiles of the mud surface the horizontal velocity distributions of the slide the evolution of the surface elevations and the distributions of the particle velocity of the water motion three major parameters dominate the magnitude of the waves if the volume of the mud is fixed the density of mud the yield stress of the mud and the depth of water at the mudslide site because of the yield stress the slides stop on the slope when the shear stress exerted on the bottom become smaller than the yield stress the bingham plastic behavior of the mud significantly reduces the extent and the speed of the mudslide and also the magnitude of the surface waves generated comparison of the solution of the bingham plastic mudslide model with a snow flow test is presented the solution of a viscous fluid model has been derived as a special case of the present solution

coseismic fault related folding during the south golbaf earthquake of november 20 1989 in southeast iran the south golbaf earthquake of november 20 1989 m s 5 7 m b 5 6 i vii in southeast iran was associated with coseismic surface faulting and folding surface faults 11 km west dipping and 8 km east dipping long with oblique reverse mechanisms developed on both sides of a small holocene playa apparently repeated coseismic fault related folding was responsible for the holocene 20 tilting of the playa deposits above the active fault tip at the ground surface this study provided the first evidence of earthquake folding of holocene playa deposits in iran

a hybrid method for the estimation of ground motion in sedimentary basins quantitative modeling for mexico city to estimate the ground motion in two dimensional 2d laterally heterogeneous anelastic media a hybrid technique has been developed that combines modal summation and the finite difference method in the calculation of the local wave field owing to a seismic event both for small and large epicentral distances it is possible to take into account the source path and local soil effects as a practical application we have simulated the ground motion in mexico city caused by the michoacan earthquake of september 19 1985 by studying the one dimensional 1d response of the two sedimentary layers present in mexico city it is possible to explain the difference in amplitudes observed between records for receivers inside and outside the lake bed zone these simple models show that the sedimentary cover produces the concentration of high frequency waves 0 2 to 0 5 hz on the horizontal components of motion the large amplitude coda of ground motion observed inside the lake bed zone and the spectral ratios between signals observed inside and outside the lake bed zone can only be explained by 2d models of the sedimentary basin in such models the ground motion is mainly controlled by the response of the uppermost clay layer the synthetic signals explain the major characteristics relative amplitudes spectral ratios and frequency content of the observed ground motion the large amplitude coda of the ground motion observed in the lake bed zone can be explained as resonance effects and the excitation of local surface waves in the laterally heterogeneous clay layer also for the 1985 michoacan event the energy contributions of the three subevents are important to explain the observed durations

numerical simulation of the landslide generated tsunami in kitimat arm british columbia canada 27 april 1975 1 it remains challenging to predict and estimate potential damage from tsunamis using computer models one of the approaches to validate models is to compare their results with site observations we carried out numerical modeling for both the underwater landslide and the associated tsunami that occurred near kitimat british columbia canada on 27 april 1975 a few observations of high water marks along the coastline indicated 8 2 m tsunami waves previous survey results of the seafloor showed that a landslide traveled about 5 km down the axis of the fjord from its source areas on the sidewall of the fjord near the head of the inlet and on the lower kitimat river delta we modeled the subaqueous slope failure as a bingham visco plastic fluid debris flow based on previous geotechnical investigations at the site and numerically solved the landslide generated tsunami wave and debris flow equations using a finite volume godunov type scheme this method resolves abrupt wave and landslide front interactions and remains oscillation free the computed motion of the debris flow is generally consistent with observations simulations indicate that the failure propagated approximately 4 5 km down the fjord axis from its inception point we have found that computed amplitudes for the tsunami wave crest at the coast of kitimat arm were between 6 and 11 m these values are somewhat higher than previous simplistic solitary wave theory estimates of 6 3 m and observations of 8 2 m

strong motion and teleseismic waveform inversions for the source process of the 2003 bam iran earthquake the bam earthquake m w 6 5 occurred on 26 december 2003 in southeastern iran causing a major disaster in the city of bam a remarkable vertical peak ground acceleration value of 988 cm s2 and two horizontal pulses were recorded inside the damaged city previous analyses showed that the earthquake was caused by a subsurface rupture on an unknown strike slip fault in this study we attempt to determine the precise fault location and source process of the 2003 bam earthquake by performing a multiple time window linear waveform inversion of teleseismic and strong motion data both individually and jointly we examined the general features of the fault location and the source process by analyzing the teleseismic displacement waveforms and determined the precise features and fault geometry by inverting the three components of strong motion velocity records the final estimate of the source process of the 2003 bam earthquake was determined by joint inversion of the datasets our results show that a single fault model characterized by the appropriate location of the hypocenter rake angle variations and the rayleigh like speed of the rupture front can satisfactorily explain the three components of the strong motion records at bam station

the 2003 december 26 bam earthquake iran mw 6 6 aftershock sequence summary from 2003 december 29 to 2004 january 30 a dense seismological network of 23 stations was installed in the epicentral area of the 2003 december 26 bam earthquake to study the aftershock seismicity we select the 331 earthquakes recorded at a minimum of 10 stations with rms less than 0 1 s and uncertainties less than 1 km to infer the precise geometry of the seismicity in the fault region we also process the data with the double difference technique to confirm the results the aftershock cluster is 25 km long trends north south and is located 5 km west of the bam baravat escarpment exactly beneath the observed surface breaks at depth aftershocks are concentrated between 6 and 20 km beneath the upper layer of relatively low velocity that experienced the maximum slip and they dip slightly westward the southernmost part of the aftershock cluster is narrow and defines the rupture zone that is likely the bam baravat fault at depth however it is unlikely that it is connected at surface to the bam baravat escarpment but more likely to the co seismic ruptures south of bam on the contrary the distribution of the northernmost aftershocks spread into a more complex pattern which is consistent with a northward propagation of the rupture along the fault plane the focal mechanisms are consistent with right lateral strike slip faulting on n s trending faults parallel to the bam baravat escarpment

the 2003 bam se iran earthquake precise source parameters from satellite radar interferometry summary differential radar interferometry provided high quality near field deformation data for the 2003 bam earthquake and therefore strong constraints on its source parameters the ruptured fault segments could be clearly detected by using a sobel edge filter on the phase unwrapped deformation field the estimated total rupture length is about 24 km more than 80 per cent of the seismic moment was released from its southern segment of about 13 km where the slip reached a maximum of up to 270 cm resulting in a stress drop of at least 6 mpa in addition optical remote sensing data show that the bam fault is not a single fault but consists of a 4 5 km wide fault system with the known main branch running between the city of bam and baravat the fault ruptured by the bam earthquake appears to continue the nw branch of this fault system from bam city southwards based on these results we suggest that the bam earthquake ruptured a hidden or new fault and that in this process an unusually strong asperity was involved

laboratory analysis of mudflow properties a rotational viscometer has been designed for laboratory measurements of the rheological properties of natural mudflow deposits in colorado the mudflow matrices comprised of silt and clay particles are sheared under temperature controlled conditions at volumetric sediment concentrations ranging from 0 10 0 45 this study stresses the importance of conducting rheological measurements at low rates of shear because 1 those are the conditions found in natural channels and 2 they avoid the slippage problems observed at large sediment concentrations at low rates of shear the bingham model is fitted to the measured rheograms and both the viscosity and yield stress increase exponentially with the sediment concentration of the fluid matrix both the yield stress and the viscosity increase by three orders of magnitude as the volumetric concentration of sediments in the fluid matrix changes from 10 to 40 the addition of sand particles does not significantly alter the rheological properties of the matrix unless the volumetric concentration of sands exceeds 0 20

combined effects of tectonic and landslide generated tsunami runup at seward alaska during the mw 9 2 1964 earthquake we apply a recently developed and validated numerical model of tsunami propagation and runup to study the inundation of resurrection bay and the town of seward by the 1964 alaska tsunami seward was hit by both tectonic and landslide generated tsunami waves during the m rm w 9 2 1964 megathrust earthquake the earthquake triggered a series of submarine mass failures around the fjord which resulted in landsliding of part of the coastline into the water along with the loss of the port facilities these submarine mass failures generated local waves in the bay within 5 min of the beginning of strong ground motion recent studies estimate the total volume of underwater slide material that moved in resurrection bay to be about 211 million m3 haeussler et al in submarine mass movements and their consequences pp 269 278 2007 the first tectonic tsunami wave arrived in resurrection bay about 30 min after the main shock and was about the same height as the local landslide generated waves our previous numerical study which focused only on the local landslide generated waves in resurrection bay demonstrated that they were produced by a number of different slope failures and estimated relative contributions of different submarine slide complexes into tsunami amplitudes suleimani et al in pure appl geophys 166 131 152 2009 this work extends the previous study by calculating tsunami inundation in resurrection bay caused by the combined impact of landslide generated waves and the tectonic tsunami and comparing the composite inundation area with observations to simulate landslide tsunami runup in seward we use a viscous slide model of jiang and leblond j phys oceanogr 24 3 559 572 1994 coupled with nonlinear shallow water equations the input data set includes a high resolution multibeam bathymetry and lidar topography grid of resurrection bay and an initial thickness of slide material based on pre and post earthquake bathymetry difference maps for simulation of tectonic tsunami runup we derive the 1964 coseismic deformations from detailed slip distribution in the rupture area and use them as an initial condition for propagation of the tectonic tsunami the numerical model employs nonlinear shallow water equations formulated for depth averaged water fluxes and calculates a temporal position of the shoreline using a free surface moving boundary algorithm we find that the calculated tsunami runup in seward caused first by local submarine landslide generated waves and later by a tectonic tsunami is in good agreement with observations of the inundation zone the analysis of inundation caused by two different tsunami sources improves our understanding of their relative contributions and supports tsunami risk mitigation in south central alaska the record of the 1964 earthquake tsunami and submarine landslides combined with the high resolution topography and bathymetry of resurrection bay make it an ideal location for studying tectonic tsunamis in coastal regions susceptible to underwater landslides

patterns of historical earthquake rupture in the iranian plateau the iranian plateau accommodates the 35 mrn yr convergence rate be tween the eurasian and arabian plates by strike slip and reverse faults with relatively low slip rates in a zone 1000 km across although these faults have only locally been the subject of paleoseismological studies a rich historical and archeological record spans several thousand years long enough to establish recurrence intervals of 1000 to 5000 yr on individual fault segments several clusters of earthquakes provide evidence of interaction among reverse and strike slip faults probably due to adjacent faults being loaded by individual earthquakes the dasht e bayaz sequence of 1936 to 1997 includes earthquakes on left lateral right lateral and reverse faults the neyshabur sequence of four earthquakes between 1209 and 1405 respected the seg ment boundary between the neyshabur and binalud reverse fault systems the two pairs of earthquakes may have ruptured different faults in each segment similar to the 1971 and 1994 san fernando california earthquakes the 1978 tabas reverse fault earthquake was preceded by the 1968 ferdows earthquake part of the dasht e bayaz sequence the north tabriz fault system ruptured from southeast to north west in three earthquakes from 1721 to 1786 a previous cluster may have struck this region in 855 to 958 the mosha fault north of tehran ruptured in three earthquakes in 958 1665 and 1830 five large earthquakes struck the tehran region from 743 to 1177 but only two that large have struck the area since 1177 other earthquakes occurred in pairs in the talesh mountains near the caspian sea 1863 1896 the iran turkey border 1840 1843 and the nayband gowk fault system both 1981 other historical events did not occur as parts of sequences the historic seismic moment release in iran accounts for only a small part of the plate convergence rate which may be due to aseismic slip or to the iranian historical record long as it is being too short to sample long term deformation across the plateau no historic earthquakes of m 8 have struck iran however several long straight strike slip faults doruneh west neh east neh and nayband have not sustained large historical earthquakes raising the possibility that these long faults could produce earthquakes of m 8 thereby removing at least part of the apparent slip deficit an increased understanding of iran s seismic hazard could be obtained by an extensive paleoseismology program and space geodetic arrays supplementing the abundant historical and archaeological record

simulation of selected strong motion records of the 2003 mw 6 6 bam earthquake se iran the modal summation ray tracing methods in the wkbj approximation

cumulative right lateral fault slip rate across the zagros makran transfer zone role of the minab zendan fault system in accommodating arabia eurasia convergence in southeast iran the zendan minab zone is the transition zone between the zagros collision to the west and makran subduction to the east it is also linked to the north with the nayband gowk fault system that bounds the lut block to the east the total convergence rate between arabia and eurasia is estimated to range between 23 and 35 mm yr 1 in a nne trending direction the deformation through the minab zendan system is accommodated within two fault systems the western n160 e trending minab zendan fault system and the eastern north south sabzevaran jiroft fault system the study area is characterized by a well defined succession of quaternary deposit levels the age of these deposits was estimated by archaeological data regional palaeoclimate correlations and constrained by additional in situ10be dating in another paper in this study these deposits exhibit offsets both lateral and vertical that are evaluated by satellite image analysis and gps profiles thanks to offsets and ages the strike slip rates associated with the minab zendan and the sabzevaran jiroft fault systems are calculated to be 5 1 1 3 or 6 6 1 5 and 6 2 0 7 mm yr 1 respectively these results allow an evaluation of the velocity vector of the musandam peninsula oman with respect to the lut block of 11 4 2 0 or 12 9 2 2 mm yr 1 in a n10 15 e direction close to the gps estimates this study also constrains the in plane slip rates for each fault previous works indicate that the zagros accommodates only 10 mm yr 1 of shortening while 10 mm yr 1 should be accommodated by the alborz mountains in northern iran this last 10 mm yr 1 may be accommodated through the nayband gowk system and the east iranian ranges implying that the two fault systems constituting the zagros makran transfer zone have different geodynamic roles the western minab zendan fault system links the makran and zagros deforming zones whereas the northwestern jiroft sabzevaran fault system is transmitting the deformation to the nayband gowk system and then to the alborz ranges the presence of another such strike slip zone within the makran seems to indicate that the accommodation zone between the zagros and makran is wide of the order of 400 km we interpret this deformation pattern that accompanies the genesis of the immature transform zone by a flexure of the slab under the zagros makran transfer zone instead of a tear in the slab that may be expected to induce a sharper transition zone

a bingham plastic model for a muddy seabed under long waves the dynamics of cohesive mud under wave action is important to the geological processes along some coastlines because of the complex rheological properties there have been vastly different models for predicting the effect of mud on wave attenuation this paper focuses on a non newtonian behavior of highly concentrated mud whereby shearing strain occurs only if the shear stress exceeds a certain threshold called the yield stress the wave induced motion in a thin mud layer beneath a clear water layer is studied there are circumstances in which the yield stress is dominant and acts like a coulomb friction mud motion can change from continuous to intermittent as the wave attenuates the effects of the non newtonian behavior on wave damping are compared to other more common causes of dissipation

active tectonics of the alpine himalayan belt between western turkey and pakistan summary over 80 new fault plane solutions combined with satellite imagery as well as both modern and historical observations of earthquake faulting are used to investigate the active tectonics of the middle east between western turkey and pakistan the deformation of the western part of this region is dominated by the movement of continental material laterally away from the lake van region in eastern turkey this movement helps to avoid crustal thickening in the van region and allows some of the shortening between arabia and eurasia to be taken up by the thrusting of continental material over oceanic type basement in the southern caspian mediterranean makran and black sea thus central turkey bounded by the north and east anatolian strike slip faults is moving west from the van region and overrides the eastern mediterranean at two intermediate depth seismic zones one extending between antalya bay and southern cyprus and the other further west in the hellenic trench the motion of northern iran eastwards from the van region is achieved mainly by a conjugate system of strike slip faults and leads to the low angle thrusting of iran over the southern caspian sea the seismicity of the caucasus shows predominantly shortening perpendicular to the regional strike but there is also some minor elongation along the strike of the belt as the causcasus overrides the caspian and black seas the deformation of the eastern part of this region is dominated by the shortening of iran against the stable borders of turkmenistan and afghanistan the north east direction of compression seen in zagros is also seen in north east iran and the kopet dag where the shortening is taken up by a combination of strike slip and thrust faulting large structural as well as palaeomagnetic rotations are likely to have occurred in ne iran as a result of this style of deformation north south strike slip faults in southern iran allow some movement of material away from the collision zone in ne iran towards the makran subduction zone where genuinely intermediate depth seismicity is seen within this broad deforming belt large areas such as central turkey nw iran azerbaijan central iran and the southern caspian appear to be almost aseismic and therefore to behave as relatively rigid blocks surrounded by active belts 200 300 km wide the motion of these blocks can usefully be described by poles of rotation the poles presented in this paper predict motions consistent with those observed and also predict the opening of the gulf of iskenderun ne of cyprus the change within the zagros mountains from strike slip faulting in the nw to intense thrusting in the se and the relatively feeble seismicity in se iran baluchistan this description also explains why the north south structures along the iran afghanistan border do not cut the east west ranges of the makran within the active belts surrounding the relatively aseismic blocks a continuum approach is needed for a description of the deformation even though motions at the surface may be concentrated on faults the evolution of fault systems within the active zones is controlled by geometric constraints such as the requirement that simultaneously active faults do not in general intersect many of the active processes discussed in this paper particularly large scale rotations and lateral movement along the regional strike are likely to have caused substantial complexities in older mountain belts and should be accounted for in any reconstructions of them

active tectonics and late cenozoic strain distribution in central and eastern iran 1 right lateral shear between central iran and afghanistan is accommodated on n s right lateral strike slip faults surrounding the aseismic dasht e lut north of 34 n the right lateral shear is accommodated on left lateral faults that rotate clockwise about vertical axes little is known of the late tertiary and younger offsets and slip rates on the active fault systems results that are important for understanding the regional tectonics we use observations from satellite imagery to identify displaced geological and geomorphological markers which we use in conjunction with the overall morphology and orientation of the active fault systems to estimate the total cumulative right lateral shear estimates of cumulative fault movements from offset features and inferred vertical axis rotation of fault bounded blocks suggest that the late cenozoic strain is concentrated toward the eastern margin of iran along the sistan shear zone where bedrock offsets of at least 70 km are observed across the active faults the geomorphology of the deh shir anar and great kavir strike slip faults in central iran suggest that although little shortening is accommodated across this region they might still be active and hence capable of producing earthquakes present day activity on these faults in central iran would not be expected from distributions of instrumental and historical earthquakes although speculative the late tertiary strain distribution described in this paper is consistent with what we know of the present day rates of shear in eastern iran and provides a framework to which later more detailed work can be added

the coupling of a submarine slide and the surface waves which it generates underwater landslides are a common source of small scale tsunamis in coastal areas they have been the object of only a few theoretical and experimental studies a numerical model is developed to study the coupling of a submarine landslide and the surface waves which it generates a formulation of the dynamics of the problem is presented where the landslide is treated as the laminar flow of an incompressible viscous fluid and the water motion is assumed irrotational long wave approximation is adopted for both water waves and the mudslide the resulting differential equations are solved by a finite difference method we present the numerical results which contrast the behavior of the mud flow under a fixed surface in the presence of one way coupling bottom deformations affect the free surface and with full coupling surface pressure gradients react on the mud flow it is found that three main waves are generated by a landslide starting from rest on a gentle uniform slope the first wave is a crest which propagates away from the mudslide site into deeper water this crest is followed by a trough in the form of a forced wave which propagates with the speed of the mudslide front the third wave is a relatively small trough which propagates shoreward two major parameters dominate the interaction between the slide and the waves it produces the density of sliding material and the depth of water at the mudslide site the two way interactions are significant for the cases of a smaller mud density and shallower waters for the cases of larger mud density and shallower waters the two way interactions are small but the waves generated are very large for larger initiation depth of the mudslide the interactions are weak and the waves generated are small we also examined the possibility of a resonance between the slide and the waves our numerical results indicate that a resonance is not expected in many practical cases

field and teleseismic observations of the 1981 golbaf sirch earthquakes in se iran summary in 1981 june and july two large earthquakes occurred on the gowk fault system in south east iran both earthquakes were associated with surface faulting showing a combination of reverse and right lateral strike slip motion on parallel adjacent faults striking north south and dipping both east and west such motion can be seen to have occurred in the recent past and is responsible for the formation of elongated alluvium filled depressions in the footwall region common to both the east and west dipping faults the earthquake of june 11 involved motion along about 15 km of the gowk fault system with a moment of about 1 0 1026 dyne cm the earthquake of july 28 was larger and occurred farther north with movement along at least 65km of the gowk fault system and a moment of about 7 1026 dyne cm surface faulting in both earthquakes was complex and spread over several kilometres width on en echelon fault segments as well as on faults dipping both east and west the long period wwssn seismograms of these two mainshocks are unusually complicated and clearly made up of several individual subevents sensible interpretation of these waveforms without guidance from the surface faulting and the long period sro moment tensor inversion of dziewonski woodhouse would be impossible however a combination of these three data sources allows a geologically plausible interpretation of the rupture processes in these earthquakes to be made although the faulting in both mainshocks was on the same large scale feature the gowk fault the rupture zones of the two earthquakes did not apparently overlap and were separated by a gap of 5 km along strike in which both coseismic and recent geological displacements are very small rupture in both mainshocks appears to have nucleated near this gap and to have propagated away from it other such gaps are visible along the irregular displacement of the northern fault break and may have been the nucleation positions for individual subevents of the july 28 earthquake recognition of such nucleation sites is of obvious importance to earthquake prediction efforts

scenarios of tsunami amplitudes in the north eastern coast of sea of marmara generated by submarine mass failure in this paper the tsunamis resulting from a submarine mass failure such as slides and slumps triggered by earthquakes or other environmental effects which is settled at the bottom of the north eastern sea of marmara are examined in one sample region as the solution method one hybrid method is developed the main objective of this method is to combine an analytical solution presenting near field tsunami amplitudes above the submarine mass failure with a numerical solution indicating the tsunami amplitudes in the coastal regions for this purpose one common linear boundary between analytical and numerical solution domains is defined movements of submarine mass failures smf are modeled using one simple kinematics source model and the amplitudes of the tsunamis at the region that are closer to the landslide are computed by using the analytical method smf is modeled approximately from the bottom geometry and an average depth is used scenarios of smf are established depending on the velocities and thicknesses of the failure and near field tsunami amplitudes are obtained in the open sea during the source time after the source times the solutions are found in the numerical region using telemac 2d software system with the mentioned boundary above in this boundary the output of the analytical solutions is taken as the boundary conditions or the disturbances for the numerical method with these disturbances the numerical method is performed and the amplitudes are calculated in the coastal area the generation propagation and coastal amplifications of the tsunamis are illustrated at some certain points and regions both in the open sea and near the coast line the results have been visualized and discussed

mapping active fault associated with the 2003 mw 6 6 bam se iran earthquake with aster 3d images abstract satellite images reveal the geomorphology and geometry of an active fault associated with an earthquake that caused over 40 000 deaths in southeast iran this earthquake of moment magnitude mw 6 6 occurred at 01 56 52 utc on december 26 2003 near the towns of bam and baravat an active fault that ruptured during the earthquake can be seen on three dimensional 3d pre and post earthquake images generated from advanced spaceborne thermal emission and reflection radiometer aster visible and near infrared vnir data the interpretation and analysis of satellite images suggest that a dextral fault extends for 65 km through the bam baravat region it strikes north northwest and steps leftward at a segment boundary between two towns transpressional stress at this step over bend probably triggered the 2003 earthquake rupture as suggested also by source mechanism solution of the bam earthquake and by landforms observed in the field in the past 2000 years bam has had no earthquake as destructive as the one in 2003 the potential for this catastrophe could have been identified through a combination of satellite remote sensing technique and field reconnaissance

a semi spectral modelling of landslide tsunamis summary a new semi spectral technique based on integral equations is introduced for the landslide tsunami problem the technique does not use the shallow water approximation and resolves the dispersive surface wavefield generated by sliding material over a bathymetric profile the wave scattering due to the bathymetric profile on which the slide occurs is calculated solving an integral equation on the free surface the linearized kinematic and dynamic boundary conditions are imposed method of images is adopted to solve for a source sink distribution on the bathymetry to simulate the motion of the landslide and to satisfy the kinematic condition on the sea bottom an asymptotic relation for the far field is also derived the application to a landslide tsunami generation scenario in the sea of marmara reveals that a thickness h submarine mass failure on the southern rim of the c onarcok basin would create a wave peak of around 0 5 h on the 1000 m deep c onarcok basin

offset and evolution of the gowk fault s e iran a major intra continental strike slip system abstract we use drainage reconstructions to estimate long term offsets on the gowk fault an oblique right lateral strike slip fault in eastern iran on which there have been a number of recent large earthquakes a 3 km horizontal offset is inferred from well preserved geomorphology we further identify a total cumulative offset of 12 km which produces a simple reconstruction of geomorphology across the fault filling in pull apart basins restoring rivers to linear courses across the fault trace and aligning structural and bed rock features the probable age of the gowk fault and k ar dating of offset basalts north of the study region suggest an overall slip rate of 1 5 2 4 mm year this is small compared with the overall 10 20 mm year of shear expected between central iran and afghanistan and the deficit is likely to have been accommodated on other faults east of the gowk fault drainage displaced by dextral movement leads to the development of a series of basins along the fault and a longitudinal topographic profile that resembles an asymmetric saw tooth the geomorphic evolution of the fault zone at the surface includes both normal and reverse faulting components reflecting a probable ramp and flat structure in cross section this interpretation is consistent with evidence from the analysis of seismological radar and surface rupture data in recent earthquakes

the source motion of 2003 bam iran earthquake constrained by satellite and ground based geodetic data summary the interpretation of coseismic surface deformation measurements through inversion techniques is of major importance to understand the mechanical behaviour of a seismic fault dense geodetic data sets in the vicinity of the ruptured fault provide unique constraints on detailed fault geometry and slip distribution at depth making them complementary to seismological data bam earthquake mw 6 6 2003 december 26 induced surface deformation has been precisely mapped by envisat asar interferometry and by subpixel correlation techniques applied to spot 5 and asar amplitude images these oblique and horizontal estimations of deformation have been completed with one levelling profile along the main road crossing the rupture from west to east we process these data separately and jointly in a two step inversion technique within the elastic half space theory framework our objective is to determine the dislocation model at depth that satisfies simultaneously all the geodetic constraints also we estimate the relative contribution of each geodetic data set to this inversion process we first use a stochastic direct approach called neighbourhood algorithm in order to estimate the average characteristics of the rupture and their relative uncertainty constraining in this way the geometry of the ruptured fault we then linearize the inverse problem and compute the slip distribution on the fault using a standard weighted least square technique assuming the solution is smooth to some degree at each step we discuss the optimal models their stability as well as the relative influence of each data set on the derived models parameters our preferred model reveals a shallow dislocation on a quasi vertical fault slightly dipping towards east the slip vector has a strike slip component as high as 2 m while the dip slip component seems negligible however the estimation of the resolution matrices emphasizes the fact that the details of deep fault slip distribution remain out of the scope of this ill conditioned inverse problem yet our preferred model suggests a main dislocation limited at depth between 1 and 6 km by contrast the aftershocks observed in the months following the earthquake are located just beneath the estimated main shock

seismotectonic rupture process and earthquake hazard aspects of the 2003 december 26 bam iran earthquake summary the catastrophic 2003 m w 6 6 bam earthquake in southern iran attracted much attention and has been studied with an abundance of observations from synthetic aperture radar teleseismic seismology aftershock studies strong ground motion geomorphology remote sensing and surface field work many reports have focused on the details of one or other data type producing interpretations that either conflict with other data or leave questions unanswered this paper is an attempt to look at all the available data types together to produce a coherent picture of the coseismic faulting in 2003 and to examine its consequences for active tectonics and continuing seismic hazard in the region we conclude that more than 80 per cent of the moment release in the main shock occurred on a near vertical right lateral strike slip fault extending from the city of bam southwards for about 15 km with slip of up t o2mb utmostly restricted to the depth range 2 7 km analysis of the strong ground motion record at bam is consistent with this view and indicates that the extreme damage in the city can be attributed at least in part to the enhancement of ground motion in bam because of its position at the end of the northward propagating rupture little of the slip in the main shock reached the earth s surface and more importantly aftershocks reveal that 12 km vertical extent of a deeper part of the fault system remained unruptured beneath the coseismic rupture plane at depths of 8 20 km this may represent a substantial remaining seismic hazard to the reconstructed city of bam we believe that some oblique reverse slip up to 2 m and less than 20 per cent of the released seismic moment occurred at a restricted depth of 5 7 km on a blind west dipping fault that projects to the surface at the bam baravat escarpment an asymmetric anticline ridge that is the most prominent geomorphological feature in the area this fault did not rupture significantly at shallow levels in 2003 and it may also represent a continuing seismic hazard widespread distributed surface ruptures north of the city are apparently unrelated to substantial slip at depth and may be the result of enhanced ground motion related to northward propagation of the rupture the faulting at bam may be in the early stages of a spatial separation partitioning between the reverse and strike slip components of an oblique convergence across the zone such a separation is common on the continents though in this case the slip vectors between the two faults differ only by 20 as a substantial strike slip component remains on the obliquereverse fault the bam earthquake is one in a series of large earthquakes involving faulting along the western edge of the lut desert in addition to the unruptured parts of the faults near bam itself continuing and substantial hazard is represented by unruptured neighbouring faults particularly blind thrusts along the jebel barez mountains to the south and strike slip faulting at sarvestan to the west

present day crustal deformation and plate kinematics in the middle east constrained by gps measurements in iran and northern oman summary a network of 27 gps sites was implemented in iran and northern oman to measure displacements in this part of the alpine himalayan mountain belt we present and interpret the results of two surveys performed in 1999 september and 2001 october gps sites in oman show northward motion of the arabian plate relative to eurasia slower than the nuvel 1a estimates e g 22 2m m yr 1 at n8 5 e instead of 30 5 mm yr 1 at n6 e at bahrain longitude we define a gps arabia eurasia euler vector of 27 9 0 5 n 19 5 1 4 e 0 41 0 1 myr 1 the arabia eurasia convergence is accommodated differently in eastern and western iran east of 58 e most of the shortening is accommodated by the makran subduction zone 19 5 2m m yr 1 and less by the kopet dag 6 5 2m m yr 1 west of 58 e the deformation is distributed in separate fold and thrust belts at the longitude of tehran the zagros and the alborz mountain ranges accommodate 6 5 2m m yr 1 and 8 2m m yr 1 respectively the right lateral displacement along the main recent fault in the northern zagros is about 3 2m m yr 1 smaller than what was generally expected by contrast large rightlateral displacement takes place in northwestern iran up to 8 mm yr 1 the central iranian block is characterized by coherent plate motion internal deformation 2m m yr 1 sites east of 61 e show very low displacements relative to eurasia the kinematic contrast between eastern and western iran is accommodated by strike slip motions along the lut block to the south the transition zone between zagros and makran is under transpression with right lateral displacements of 11 2m m yr 1

near fault strong motion complexity of the 2003 bam earthquake iran and low frequency ground motion simulation summary the 2003 december 26 bam earthquake was an intermediate size strike slip event that occurred beneath the bam city causing more than 26000 fatalities the record of the only near fault station bam station shows a clear long period pulse in almost fault normal direction suggesting a near fault forward directivity effect contributing to the heavy damage observed in bam city in this study the long period 0 1 1 5hz strong ground motions were simulated to answer some ambiguities in source parameters for fully description of the observed motion in different components at bam station to this end the hisada s kinematic model accounting for both heterogeneous source characteristics and underground geology is applied to simulate the long period ground motion different source scenarios suggested by previous studies are examined and the optimum scenario that could provide the best fitting between the simulated and observed motions for different components was introduced the slip model and asperities as well as velocity structure parameters are optimized in order to have the best possible fit between the simulated and observed velocity time histories and spectra the good agreements between the simulated and observed low frequency motions indicate a successful identification of source and slip parameters of the bam earthquake and provide a good test for the simulation technique furthermore the uniqueness of the identified source parameters and the slip model is further checked against the observed near and far field recordings of the bam earthquake a good agreement between the simulated and the observed waveforms provides a base for model verification and results confirmation

three dimensional seismic wave propagation by modal summation method and validation it is an acquired result that in order to enable realistic earthquake hazard assessment and reliable estimation of the ground motion response to an earthquake three dimensional velocity models have to be considered in this paper we present a new analytical procedure for determining the seismic wavefield in a 3d anelastic model based on the combination of the ray theory with the modal summation method the proposed procedure has been validated by considering the three dimensional model of the kanto basin japan available in the literature three dimensional simulations were performed for the 1990 odawara earthquake the results obtained were compared both with recorded signals and with simulations available in the literature for several stations located within the kanto basin besides the advantage of being a useful tool for assessment of seismic hazard and seismic risk reduction it is characterized by high efficiency in fact once the study region is identified and the 3d model is constructed the computation at each station of the three components of the synthetic signal displacement velocity and acceleration takes less than 3 h on a 2 ghz cpu

the 2003 bam iran earthquake rupture of a blind strike slip fault a magnitude 6 5 earthquake devastated the town of bam in southeast iran on 26 december 2003 surface displacements and decorrelation effects mapped using envisat radar data reveal that over 2 m of slip occurred at depth on a fault that had not previously been identified it is common for earthquakes to occur on blind faults which despite their name usually produce long term surface effects by which their existence may be recognised however in this case there is a complete absence of morphological features associated with the seismogenic fault that destroyed bam

numerical modelling of a landslide generated tsunami the 1979 nice event on the 16th of october 1979 a part of the nice new harbour extension close to the nice international airport french riviera slumped into the mediterranean sea during landfilling operations a submarine slide with initial volume close to seashore of about 10 millions m3 which could have evolved later into an avalanche was followed by a small tsunami noticed by several witnesses in the baie des anges the maximum tsunami effects were observed 10 km from the slide location near antibes city which was inundated previous analyses used rough approximate methods and produced models which did not conveniently fit data in this paper both the slide and the generated water waves are numerically simulated on the basis of the shallow water approximation the landslide is assimilated to a heavy newtonian homogeneous fluid downslope under gravity water waves are generated by sea bottom displacements induced by the landslide taking into account a very accurate multibeam bathymetric map the nice slide of 10 millions m3 is simulated by this model the numerical results are generally consistent with the observed hydraulic local effects in front of the nice airport however they are not in agreement in the far field a larger and deeper landslide 2 km off nice airport is tested to quantitatively study the effects of the landslide volume on water waves generation

surface ruptures and building damage of the 2003 bam iran earthquake mapped by satellite synthetic aperture radar interferometric correlation 1 we use the interferometric correlation from envisat synthetic aperture radar sar images to map the details of the surface ruptures related to the 26 december 2003 earthquake that devastated bam iran the main strike slip fault rupture south of the city of bam has a series of four segments with left steps shown by a narrow line of low correlation in the coseismic interferogram this also has a clear expression in the field because of the net extension across the fault just south of the city limits the surface strain becomes distributed over a width of about 500 m probably because of a thicker layer of soft sedimentary material another fault north of bam shows offset and low correlation over a wider zone in the interferograms but it has no discrete surface rupture possibly because of a net shortening across this fault taking the difference between the interferometric correlation for an interval including the earthquake and an interval before the earthquake separates the changes due to the earthquake from other effects in the partially vegetated city of bam we map the damage to buildings by measuring the change from high correlation to low correlation where buildings were destroyed by the earthquake