extracting source characteristics and dynamics of the august 2010 mount meager landslide from broadband seismograms 1 seismic methods can substantially improve the characterization of the dynamics of large and rapid landslides such landslides often generate strong long period seismic waves due to the large scale acceleration of the entire landslide mass which according to theory can be approximated as a single force mechanism at long wavelengths i apply this theory and invert the long period seismic waves generated by the 48 5 mm3 august 2010 mount meager rockslide debris flow in british columbia using data from five broadband seismic stations 70 to 276 km from the source i obtain a time series of forces the landslide exerted on the earth with peak forces of 1 0 1011 n the direction and amplitude of the forces can be used to determine the timing and occurrence of events and subevents using this result in combination with other field and geospatial evidence i calculate an average horizontal acceleration of the rockslide of 0 39 m s2 and an average apparent coefficient of basal friction of 0 38 0 02 which suggests elevated basal fluid pressures the direction and timing of the strongest forces are consistent with the centripetal acceleration of the debris flow around corners in its path i use this correlation to estimate speeds which peak at 92 m s this study demonstrates that the time series recording of forces exerted by a large and rapid landslide derived remotely from seismic records can be used to tie post slide evidence to what actually occurred during the event and can serve to validate numerical models and theoretical methods

the dinar earthquake mw 6 2 october 1 1995 afyon turkey and earthquake hazard of the dinar civril fault a moderately strong earthquake mw 6 2 occurred in the town of dinar at 17 57 ut on october 1 1995 taking the lives of 90 people and damaging about 4500 buildings its epicenter is located near the dinar civril fault and its focal mechanism is linked to a northeast southwesterly tensional stress field arising from the interaction between the subducting african plate and the overriding aegean anatolian plate in the eastern mediterranean surface cracks of the october 1 earthquake have been observed 10 km continuously along the dinar civril fault the cracks have displayed a mode of dip slip however some have also indicated lateral slip the different modes of slip are generally in agreement with the fault plane solution and are indicators of the complex nature of the rupture process in investigating the earthquake hazard of the dinar civril fault and proximity the maximum likelihood method was used to estimate seismic hazard parameters of b value seismicity activity rate m and the expected maximum magnitude mmax the data consisted of the historical data covering the period between 1800 1900 and instrumental data between 1900 and 1992 this method allowing use of the mixed earthquake catalogue containing both historical and instrumental earthquake data yielded values of 0 70 1 92 and 7 14 for b m and mmax respectively the recurrence time estimated for an earthquake of a magnitude of mw 6 2 is 123 years the non occurrence probabilities of such an earthquake in 1 and 50 years are 0 21 and 0 04 respectively

numerical modeling of the mount meager landslide constrained by its force history derived from seismic data we focus on the 6 august 2010 mount meager landslide that occurred in southwest british columbia canada this 48 5 mm3 rockslide that rapidly changed into a debris flow was recorded by over 25 broadband seismic stations we showed that the waveform inversion of the seismic signal making it possible to calculate the time history of the force applied by the landslide to the ground is very robust and stable even when using only data from a single station by comparing this force with the force calculated through numerical modeling of the landslide we are able to support the interpretation of seismic data made using a simple block model however our study gives different values of the friction coefficients involved and more details about the volumes and orientation of the subevents and the flow trajectory and velocity our sensitivity analysis shows that the characteristics of the released mass and the friction coefficients all contribute to the amplitude and the phase of the force despite this complexity our study makes it possible to discriminate the best values of all these parameters our results suggest that comparing simulated and inverted forces helps to identify appropriate rheological laws for natural flows we also show that except for the initial collapse peaks in the low frequency force related to bends and runup over topography changes are associated with high frequency generation possibly due to an increased agitation of the granular material involved

simulating the failure process of the xinmo landslide using discontinuous deformation analysis abstract the xinmo landslide slope in sichuan china was stable during the intensive wenchuan earthquake in 2008 but failed on june 24 2017 landslide debris buried xinmo village and blocked the songpinggou river at the slope toe this study aims to clarify the post failure behavior of the landslide using two dimensional discontinuous deformation analysis 2d dda the simulation results provide comprehensive information on the initiation and the evolution of the landslide the failure process determined by the dda correlates well with the seismic signal analysis results in addition the location of the calculated rock deposit is similar to that shown by the topographic map after the landslide the maximum rock velocity in the landslide is 65 4 m s therefore the impacts of the high velocity blocks and the buildings in xinmo village must be considered to simulate the burial of xinmo village by rocks and the transport of additional rocks across the songpinggou river this xinmo landslide study demonstrates that the dda accurately simulates the post failure behavior and determines the impact area of a landslide with complicated failure processes and topography

microbial distributions detected by an oligonucleotide microarray across geochemical zones associated with methane in marine sediments from the ulleung basin abstract the biogeochemical processes that occur in marine sediments on continental margins are complex however from one perspective they can be considered with respect to three geochemical zones based on the presence and form of methane sulfate methane transition smtz gas hydrate stability zone ghsz and free gas zone fgz these geochemical zones may harbor distinct microbial communities that are important in biogeochemical carbon cycles the objective of this study was to describe the microbial communities in sediments from the smtz ghsz and fgz using molecular ecology methods i e phylochip microarray analysis and terminal restriction fragment length polymorphism t rflp and examining the results in the context of non biological parameters in the sediments non metric multidimensional scaling and multi response permutation procedures were used to determine whether microbial community compositions were significantly different in the three geochemical zones and to correlate samples with abiotic characteristics of the sediments this analysis indicated that microbial communities from all three zones were distinct from one another and that variables such as sulfate concentration hydrate saturation of the nearest gas hydrate layer and depth or unmeasured variables associated with depth e g temperature pressure were correlated to differences between the three zones the archaeal anaerobic methanotrophs typically attributed to performing anaerobic oxidation of methane were not detected in the smtz however the marine benthic group b which is often found in smtz was detected within the ghsz samples that were typically closer to layers that contained higher hydrate saturation had indicator sequences related to vibrio type taxa these results suggest that the biogeographic patterns of microbial communities in marine sediments are distinct based on geochemical zones defined by methane

palaeoseismological investigation of the tyrnavos fault thessaly central greece abstract a palaeoseismological investigation has been carried out along the tyrnavos fault an ese wnw trending north dipping normal fault representing one of the major tectonic structures bordering the late pleistocene holocene tyrnavos basin northern thessaly central greece according to geological structural morphotectonic and geophysical researches the tyrnavos fault has been geometrically and kinematically characterised as a typical aegean type active fault six trenches have been excavated and logged in detail in order to quantify the most important seismotectonic parameters like the characteristics of past earthquakes their ages the elapsed time from the last event the short term slip rate and the mean return period several samples have been also collected for absolute dating that has been performed with different techniques like tl osl and ams sedimentological structural and chronological data document a late pleistocene to holocene morphogenic activity of the tyrnavos fault which is characterised by vertical co seismic displacements of 20 40 cm and possible recurrence interval of 2 2 5 ka the comparison between the estimated short term ca 0 05 0 1 mm a and long term 0 1 0 2 mm a slip rates and the elapsed time from the last earthquake suggest the occurrence of a possible seismic gap along the tyrnavos fault due to the peculiar position of the selected site at the termination of the fault scarp in the bedrock the lateral variability in morphogenic behaviour of an active fault is also observed the location of the fault within a highly populated region and the proximity to the third largest town of greece larissa increases the seismic hazard of the area

spatiotemporal sequence of himalayan debris flow from analysis of high frequency seismic noise 1 during the 2003 summer monsoon the hi climb seismological stations deployed across the himalayan range detected bursts of high frequency seismic noise that lasted several hours to days on the basis of the cross correlation of seismic envelopes recorded at 11 stations we show that the largest transient event on 15 august was located nearby a village partially destroyed on that day by a devastating debris flow this consistency in both space and time suggests that high frequency seismic noise analysis can be used to monitor debris flow generation as well as the evacuation of the sediment a systematic study of one year of seismic noise focusing on the detection of similar events provides information on the spatial and temporal occurrence of mass movements at the front of the himalayas with a 50 probability of occurrence of a daily event a total of 46 debris flows are seismically detected most of them were generated in regions of steep slopes large gullies and loose soils during the 2003 summer monsoon storms these events are compared to local meteorological data to determine rainfall thresholds for slope failures including the cumulative rainfall needed to bring the soil moisture content to failure capacity the inferred thresholds are consistent with previous estimates deduced from soil studies as well as sediment supply investigations in the area these results point out the potential of using seismic noise as a dedicated tool for monitoring the spatiotemporal occurrence of landslides and debris flows on a regional scale

the influence of loess cave development upon landslides and geomorphologic evolution a case study from the northwest loess plateau china abstract loess caves landslides collapses bank erosion and soil erosion which are independently and interactively shaping the modern loess landscape are widely distributed across the chinese loess plateau the study area is located in a small watershed in huining county gansu province which is one of the areas with the strongest development of loess caves across the loess plateau this area is an ideal site for studying geological hazards and geomorphic evolution on the loess plateau seventeen landslides and 176 loess caves with a density of 887 units km2 were investigated with a uav unmanned aerial vehicle and mapped by gis geographic information system using high resolution uav images and topographic data we carried out an interpretation of loess caves bank erosion and landslides studied the spatial distribution and developmental patterns of loess caves landform morphology and the relationship between loess caves and landslides based on gis spatial analysis mathematical statistics and field surveys and analyzed the influence of loess microtopography on slope landforms finally six typical evolutionary models of soil erosion loess cave development landslide occurrence barrier dam formation are preliminarily proposed the primary slope stage early cave stage accelerated cave stage cave connecting stage landslide creeping stage and landslide dam forming stage this study is a useful exploration and an attempt to reveal the influence of loess cave development on slope stability and disaster chain effects

characterization of alpine rockslides using statistical analysis of seismic signals 1 seismic data analysis is a powerful tool for remote characterization of rock slope failures here we develop quantitative estimates of fundamental rockslide properties e g volume based solely on data from an existing regional seismic network we assembled a data set of twenty known rockslides in the central alps with volumes between 1 000 and 2 000 000 m3 and analyzed their corresponding seismograms common signal characteristics include emergent onsets slowly decaying tails and a triangular spectrogram shape the main component of seismic energy is contained in frequencies below 3 4 hz while higher frequency signals may be caused by block impacts location estimates were generated using automatic arrival time picks and resulted in a mean location error of 10 9 km a linear relationship for the detection limit of a rockslide as a function of volume was identified for our seismic station network to estimate rockslide volume runout distance drop height potential energy and fahrboschung angle of reach we extracted five simple metrics from each seismogram signal duration peak value of the ground velocity envelope velocity envelope area risetime and average ground velocity using multivariate linear regression the combination of duration peak envelope velocity and envelope area best estimated event parameters with r2 values ranging between 0 8 and 0 88 three new rockslides were then used to validate our method and volume runout drop height and potential energy were estimated within the correct order of magnitude when provided with a suitable data set of rockslide events our method can be easily adapted to other regions and seismic networks

progressive development of the buyuk menderes graben based on new data western turkey oblique and normal fault systems exposed in the buyuk menderes graben bmg region record two successive and independent complex tectonic events the first group tectonic event is defined by an e w extension related to n s contraction and transpression this group is responsible for the development of nw and ne trending conjugate pairs of oblique faults which controlled early middle miocene basin formation between the early middle miocene and plio quaternary strata exists an unconformity indicating a period of folding uplift and severe erosion associated with n s shortening the second group of events was the change in tectonic regime from e w extension to n s extension which controlled the formation of the buyuk menderes graben by three progressive pulses of deformation the first pulse of extensional deformation was initially recorded in the region by the exhumation of the deep part of the menderes massif mm with the development of the e trending buyuk menderes detachment fault bmdf the minimum age of this pulse is constrained by the older plio quaternary fluviatile deposits of the buyuk menderes graben that range in age from the plio pleistocene boundary interval to late pleistocene the second pulse which is marked by the rapid deposition of alluvial deposits initiated the formation of approximately e w trending high angle normal faults synthetic and antithetic to the buyuk menderes detachment fault on the northern margin during holocene times these faults are interpreted as secondary steeper listric faults that merge with the main buyuk menderes detachment fault at depth the third pulse was the migration of the buyuk menderes graben depocentre to the present day position by diachronous activity of secondary steeper listric faults these steeper faults are the most seismically active tectonic elements in western turkey according to the stratigraphic and structural data the n s extension in the buyuk menderes graben region produced a progressive deformation phase with different pulses during its plio quaternary evolution with migration of deformation from the master fault to the hangingwall the formation of diachronous secondary synthetic and antithetic steeper faults on the upper plate of the buyuk menderes detachment fault hence the southward migration of the deformation and of the buyuk menderes graben depocentre should be related to the evolution of detachment in the region the presence of the seismically active splays of secondary faults implies an active detachment system in the region this young plio quaternary n s extension in the buyuk menderes graben may be attributed to the combined effects of the two continuing processes in aegean region the first process is back arc spreading or probably the roll back of african slab below the south aegean arc which seems to be responsible for the change in the stress tensor from e w extension to n s extension the second and later event is the southwestward escape of the anatolian block along its boundary fault that is the north anatolian fault naf

new dynamic procedure for back calculating the shear strength parameters of large landslides abstract case histories of the tsaoling landslide and the chiu fen erh shan landslide both located in taiwan are used in this study to validate the procedure proposed for the dynamic back calculation of the shear strength parameters of the sliding surfaces of large landslides this new procedure uses the newmark sliding model while simultaneously considering the critical displacement concept the premise of the new procedure is that in a stable slope back calculation tends to underestimate the shear strength however as the intensity of earthquake shaking increases and the slope approaches failure the back calculated shear strength will approach to the true value based on this concept the new procedure method is developed and validated with the two well documented case histories the shear strength parameters back calculated using the proposed method agree well with those reported in the literature the new dynamic back calculation procedure is especially suitable in the situation where groundwater monitoring data are unavailable thus the new method is complementary to the traditional groundwater based limiting equilibrium back calculation approach

the 1 october 1995 dinar earthquake sw turkey the dinar earthquake ms 6 1 usgs pde of 1 october 1995 occurred on the nwse trending dinar fault the earthquake is associated with a 10 km long surface rupture with predominantly normal faulting the mainshock was preceded by a series of foreshocks that started 6 days before the mainshock and included two md 4 5 events the mainshock source mechanism derived from the inversion of broad band p waves revealed that two sub events occurred on a nw se trending normal fault with a small strike slip component according to the source model estimated in this study the first rupture started at a depth of about 8 km and reached to a depth of about 12 km propagating north west the total seismic moment found from the inversion of p waveforms is 2 0 times 10 18 nm the seismic moment of the second sub event was about four times larger than the first one field observations gps measurements and slip vector obtained from the inversion of broad band p waveforms suggest that the nw se trending dinar fault is due to the internal deformation of sw anatolia moving south westwards

microbial community distribution in sediments from the mount elbert gas hydrate stratigraphic test well alaska north slope we studied the microbial communities collected from hydrate bearing sediments on the north slope of alaska to determine how abiotic variables e g grain size hydrate presence formation fluid gases may correspond to the type and distribution of microbes in the sediments the cores were acquired from sub permafrost eocene 46 55 million year old sediments in the bpxa doe usgs mount elbert gas hydrate stratigraphic test well within which hydrates are believed to have formed 1 5 mya forty samples eight of which originally contained hydrates were acquired from depths of ca 606 666 m below land surface five drilling fluid samples acquired from the same depth range were included in the analysis as a control for possible contamination by drilling fluid microbes during the drilling and handling of cores dna was extracted from 15 samples typically 1 ng dna g sediment was recovered and then amplified using polymerase chain reaction with primers specific for bacterial and archaeal 16s rdna genes which indicates the likelihood that microbes were present in all analyzed samples only bacterial dna amplicons were detected terminal restriction fragment length polymorphism t rflp was used to measure bacterial diversity in the respective samples non metric multidimensional scaling nms was used to determine the abiotic variables that may have influenced bacterial diversity nms analysis revealed that the microbial taxa present in the sediment were distinct from the taxa present in the drilling fluids suggesting that the sediments were not contaminated by the drilling fluids multi response permutation procedures mrpp found no significant difference between three sample groups identified a priori as being from within a hydrate zone outside of hydrate zone or on the edge of a hydrate non hydrate zone according to downhole nuclear magnetic resonance spectroscopy logs however among the several other abiotic parameters that were evaluated mud gas methane concentration and variables related to hydrate presence e g chloride concentration salinity and resistivity appeared to define the arrangement of microbial community signatures in plots resulting from nms analysis communities from hydrate and non hydrate layers each contained unique taxa as determined by the t rflp assay

site amplifications for generic rock sites seismic shear wave velocity as a function of depth for generic rock sites has been estimated from borehole data and studies of crustal velocities and these velocities have been used to compute frequency dependent amplifications for zero attenuation for use in simulations of strong ground motion we define a genetic rock site as one whose velocity at shallow depths equals the average of those from the rock sites sampled by the borehole data most of the boreholes are in populated areas for that reason the rock sites sampled are of particular engineering significance we consider two genetic rock sites rock corresponding to the bulk of the borehole data and very hard rock such as is found in glaciated regions in large areas of eastern north america or in portions of western north america the amplifications on rock sites can be in excess of 3 5 at high frequencies in contrast to the amplifications of less than 1 2 on very hard rock sites the consideration of unattenuated amplification alone is computationally convenient but what matters for ground motion estimation is the combined effect of amplification and attenuation for reasonable values of the attenuation parameter k 0 the combined effect of attenuation and amplification for rock sites peaks between about 2 and 5 hz with a maximum level of less than 1 8 the combined effect is about a factor of 1 5 at 1 hz and is less than unity for frequencies in the range of 10 to 20 hz depending on t using these amplifications we find provisional values of about ao 70 bars and k 0 0 035 sec for rock sites in western north america by fitting our empirically determined response spectra for an m 6 5 event to simulated values the borehole data yield shear velocities 033o of 618 and 306 rrdsec for rock and soil sites respectively when averaged over the upper 30 m from this we recommend that v30 equals 620 and 310 m sec for applications requiring the average velocity for rock and soil sites in western north america by combining the amplifications for rock sites and the site factors obtained from our analysis of strong motion data we derive amplifications for sites with 17 3o 520 m sec nehrp class c corresponding to a mix of rock and soil sites and v3o 310 and 255 m sec average soil and nehrp class d sites respectively for the average soil site the combined effect of amplification and attenuation exceeds a factor of 2 0 for frequencies between 0 4 and about 4 hz with a peak site effect of 2 4 the peak of the nehrp class d site effect is 2 7

faulting associated with historical and recent earthquakes in the eastern mediterranean region summary this paper summarizes evidence for surface faulting in historical and recent earthquakes in the eastern mediterranean region and in the middle east such information is particularly important for studies of active tectonics and for palaeoseismology we have found 78 cases of faulting pre 1900 and 72 post 1900 some of which show that faults that have apparently been inactive this century had already ruptured before 1900 for some cases faulting could not have been predicted from 20th century activity and in others it could have been expected but has not been observed during the instrumental period the data are suycient to allow the derivation of relationships between magnitude and rupture length

seismic monitoring of rockfalls slide quakes and fissure development at the super sauze mudslide french alps applying the method nanoseismic monitoring to the fast moving mudslide in super sauze french alps we observed different types of seismic events caused by varying slope dynamics we identified signals caused by rockfalls in the source area of the slope and different types of signals which had obviously been generated by material failure within the unstable part of the mudslide signal analysis and further investigations e g the analysis of magnitude frequency distribution and simultaneous measurements by nanoseismic monitoring and extensometer devices revealed the generation of the observed seismic signals fracture processes i e slide quakes within the unstable sediments and the development of fissures at the slope s surface the spatial distribution of the epicenters slide quakes respectively the estimated source area fissure development correlates well with parts of the slope moving with higher velocities at the surface most of these signals were generated close to the in situ crests which are mostly covered by the mudslide material today indicating specific dynamics in these particular slope areas

landslide reconstruction using seismic signal characteristics and numerical simulations case study of the 2017 6 24 xinmo landslide abstract landslide modeling based on seismic signal characteristics is an effective method to study landslide evolution the scientific challenge lies in how to systematically characterize and reconstruct the entire landslide evolution process using the recorded seismic data we selected the 2017 6 24 xinmo landslide as a case study empirical mode decomposition emd is used to analyze the seismic signals from 14 seismic stations near the landslide area numerical simulations using two dimensional discrete element methods dem are performed to simulate landslide dynamics using the calculated kinetic energy profile after analyzing the short time fourier transform stft and fast fourier transform fft characteristics of the signal the landslide process is reconstructed and compared with the dem simulation the landslide process is observed to consist of a stationary stage slipping stage transition stage entrainment transportation stage and a deposition stage this is the first study that uses seismic signals to identify a transition stage which is a feature that is difficult to constrain from field survey and analysis alone landslide development and movement in the transition stage are discussed considering the sedimentology of the study area this study provides improved theoretical guidance for the reconstruction and characterization of landslide processes by seismic signals

new empirical relationships among magnitude rupture length rupture width rupture area and surface displacement source parameters for historical earthquakes worldwide are compiled to develop a series of empirical relationships among moment magnitude m surface rupture length subsurface rupture length downdip rupture width rupture area and maximum and average displacement per event the resulting data base is a significant update of previous compilations and includes the additional source parameters of seismic moment moment magnitude subsurface rupture length downdip rupture width and average surface displacement each source parameter is classified as reliable or unreliable based on our evaluation of the accuracy of individual values only the reliable source parameters are used in the final analyses in comparing source parameters we note the following trends 1 generally the length of rupture at the surface is equal to 75 of the subsurface rupture length however the ratio of surface rupture length to subsurface rupture length increases with magnitude 2 the average surface displacement per event is about one half the maximum surface displacement per event and 3 the average subsurface displacement on the fault plane is less than the maximum surface displacement but more than the average surface displacement thus for most earthquakes in this data base slip on the fault plane at seismogenic depths is manifested by similar displacements at the surface log linear regressions between earthquake magnitude and surface rupture length subsurface rupture length and rupture area are especially well correlated showing standard deviations of 0 25 to 0 35 magnitude units most relationships are not statistically different at a 95 significance level as a function of the style of faulting thus we consider the regressions for all slip types to be appropriate for most applications regressions between magnitude and displacement magnitude and rupture width and between displacement and rupture length are less well correlated and have larger standard deviation than regressions between magnitude and length or area the large number of data points in most of these regressions and their statistical stability suggest that they are unlikely to change significantly in response to additional data separating the data according to extensional and compressional tectonic environments neither provides statistically different results nor improves the statistical significance of the regressions regressions for cases in which earthquake magnitude is either the independent or the dependent parameter can be used to estimate maximum earthquake magnitudes both for surface faults and for subsurface seismic sources such as blind faults and to estimate the expected surface displacement along a fault for a given size earthquake

analysis of rock fall and rock fall avalanche seismograms in the french alps this study reviews seismograms from 10 rock fall events recorded between 1992 and 2001 by the permanent seismological network sismalp in the french alps a new seismic magnitude scale was defined which allowed us to compare and classify g round motion vibrations generated by these alpine rock falls each rock fall has also been cha racterized by its ground motion duration t30 at an epicentral distance of 30 km no relation was found between rock fall parameters fall height runout distance volume potential energy and rock fall s eismic magnitudes derived from seismogram amplitudes on the other hand the signal duration t30 shows a rough correlation with the potential energy and the runout distance highlighting the co ntrol of the propagation phase on the signal length the signal analysis suggests the existence of at le ast two distinct seismic sources one corresponding to the initial rupture associated with an elastic r ebound during the detachment and the other one generated by the rock impact on the slope although the fall phenomenon includes other complex processes fragmentation of the block interaction with topography plastic deformation during and after impact 2d finite element simulations of thes e two seismic sources are able to retrieve the main seismogram characteristics

contribution of thermogenic organic matter to the formation of biogenic gas hydrate evidence from geochemical and microbial characteristics of hydrate containing sediments in the taixinan basin south china sea abstract high saturation 40 100 microbial gas hydrates have been acquired by expedition gmgs2 from the taixinan basin in this study geochemical and microbial features of hydrate containing sediments from the drilling cores gmgs2 09 and gmgs2 16 were characterized to explore their relationships with gas hydrate formation results showed that the average toc content of gmgs2 09 and gmgs2 16 were 0 45 and 0 63 respectively they could meet the threshold for in situ gas hydrate formation but were not available for the formation of high saturation gas hydrates the dominant members of bacteria at the class taxonomic level were alphaproteobacteria bacilli bacteroidia epsilonproteobacteria and gammaproteobacteria and those in archaea were marine benthic group b mbgb miscellaneous crenarchaeotic group mcg group c3 methanomicrobia and methanobacteria indicators of microbes associated with thermogenic organic matter were measured these include 1 most of the dominant microbes had been found dominant in other gas hydrates bearing sediments mud volcanos as well as oil coal deposits 2 hydrogenotrophic methanogens and an oilfield origin thermophilic methylotrophic methanogen were found dominant the methanogen community 3 hydrocarbon assimilating bacteria and other hyperthermophiles were frequently detected therefore thermogenic signatures were inferred existed in the sediments this deduction is consistent with the interpretation from the seismic reflection profiles owing to the inconsistency between low toc content and gas hydrates with high saturation secondary microbial methane generated from the bioconversion of thermogenic organic matters oil or coal was speculated to serve as enhanced gas flux for the formation of high saturation gas hydrates a preliminary formation model of high saturation biogenic gas hydrates was proposed in which diagenesis processes tectonic movements and microbial activities were all emphasized regarding to their contribution to gas hydrates formation in short this research helps explain how microbial act and what kind of organic matter they use in forming biogenic gas hydrates with high saturations

relationships between fault geometry slip rate variability and earthquake recurrence in extensional settings field observations and modelling indicate that elastic interaction between active faults can lead to variations in earthquake recurrence intervals measured on timescales of 102 104 yr fault geometry strongly influences the nature of the interaction between adjacent structures as it controls the spatial redistribution of stress when rupture occurs in this paper we use a previously published numerical model for elastic interaction between spontaneously growing faults to investigate the relationships between fault geometry fault slip rate variations and the statistics of earthquake recurrence these relationships develop and become systematic as a long term consequence of stress redistribution in individual rupture events even though on short timescales earthquake activity appears to be stochastic we characterize fault behaviour using the coefficient of variation cv of earthquake recurrence intervals and introduce a new measure slip rate variability srv that takes into account the size and time ordering of slip events cv generally increases when the strain is partitioned on more than one fault but the relationship between long term fault slip rate srmean and cv is poorly defined in contrast srv increases systematically where faulting is more distributed and srmean is lower to first order srv is inversely proportional to srmean we also extract earthquake recurrence statistics and compare these to previously published probability density functions used in earthquake forecasting the histograms of earthquake recurrence vary systematically as a function of fault geometry and are best characterized by a weibull distribution with fitting parameters that vary from site to site along the fault array we explain these phenomena in terms of a time varying geometrical control on stress loading of individual faults arising from the history of elastic interactions and compare our results with published data on srv and earthquake recurrence along normal faults in new zealand and in the italian apennines our results suggest that palaeoseismic data should be collected and analysed with structural geometry in mind and that information on srv cv and srmean should be integrated with data from earthquake catalogues when evaluating seismic hazard

estimating rates of debris flow entrainment from ground vibrations debris flows generate seismic waves as they travel downslope and can become more dangerous as they entrain sediment along their path we present field observations that show a systematic relation between the magnitude of seismic waves and the amount of erodible sediment beneath the flow specifically we observe that a debris flow traveling along a channel filled initially with sediment 0 34 m thick generates about 2 orders of magnitude less spectral power than a similar sized flow over the same channel without sediment fill we adapt a model from fluvial seismology to explain this observation and then invert it to estimate the level of bed sediment and rate of entrainment beneath a passing series of surges our estimates compare favorably with previous direct measurements of entrainment rates at the site suggesting the approach may be a new indirect way to obtain rare field constraints needed to test models of debris flow entrainment

in situ fluxes and zonation of microbial activity in surface sediments of the hakon mosby mud volcano from the hakon mosby mud volcano hmmv on the southwest barents sea shelf gas and fluids are expelled by active mud volcanism we studied the mass transfer phenomena and microbial conversions in the surface layers using in situ microsensor measurements and on retrieved cores the hmmv consists of three concentric habitats a central area with gray mud a surrounding area covered by white mats of big sulfide oxidizing filamentous bacteria beggiatoa and a peripheral area colonized by symbiontic tube worms pogonophora a fourth habitat comprised gray microbial mats near gas seeps the differences between these four methane fueled habitats are best explained by different transport rates of sulfate into the sediments and pore water upflow rates the upflow velocities were estimated by two independent methods at 3 6 m yr21 in the central area and 0 3 1 m yr21 in beggiatoa mats in the central area no sulfide was found indicating that the rapidly rising sulfate free fluids caused sulfate limitation that inhibited anaerobic oxidation of methane aom under beggiatoa mats a steep sulfide peak was found at 2 to 3 cm below the seafloor bsf most likely due to aom all sulfide was oxidized anaerobically possibly through nitrate reduction by beggiatoa the beggiatoa mats were dominated by a single filamentous morphotype with a diameter of 10 mm and abundant sulfur inclusions a high diversity of sulfide oxidizer morphotypes was observed in a grayish microbial mat near gas vents where aerobic sulfide oxidation was important the sediments colonized by pogonophora were influenced by bioventilation allowing sulfate penetration and aom to 70 cm bsf the hmmv is a unique and diverse ecosystem the structure and functioning of which is mainly controlled by pore water flow

hydroacoustic detection of submarine landslides on kilauea volcano landslides produced at the site where lava flows intothe o cean at kilauea vo lcanohave been detected hy droacoustically up to 10 landslides per day were detected by a hydrophone on the hawaii undersea geo observatory hugo located 50 km south of the entry site the largest of these landslides partly subaerial events known as bench collapses were detected by a network of hydrophones in the eastern pacific 5000 7000 km away from the source the landslides display a characteristic spectral signature eas ily recognizable among other signals such as earthquake t phases and anthropogenic noises the fact that signals are detected at great distances suggests that hydroacoustic de tection of landslides could be a powerful tool in tsunami monitoring and modeling efforts

palaeoseismicity of the dinar fault sw turkey the nw se trending dinar fault is an active normal fault upon which the 1 october 1995 earthquake m 6 1 occurred the 1995 earthquake resulted in a c 10 km long surface rupture with the south side down thrown by 50 cm investigations of two trench sites perpendicular to the 1995 rupture suggest at least two prior large earthquakes in historical times radiocarbon dates and historical records constrain the age of events between 1500 bc and ad 53 event 2 possibly coinciding with the earthquake that damaged dinar the ancient city of apamea kibotos in c 80 bc and event 1 around 1500 bc surface displacements determined for events 1 and 2 compared to the 1995 surface faulting indicate that m 6 8 earthquakes were associated with each rupture using the total displacement in trenches a slip rate of about 1 mm yr 1 can be estimated for the dinar fault observations suggest that the return period for large earthquakes in the dinar area is about 1500 2000 years

rift formation in the gokova region southwest anatolia implications for the opening of the aegean sea the time of the onset and the nature of the extension in the aegean area have been problematic owing to the confusion of neotectonic replacement structures with neotectonic revolutionary structures this paper concerns two rift systems of different ages and orientations in the gokova region of southwestern anatolia the first system has a northwest southeast trend with a middle to upper miocene infill whereas the second system is orientated in an east west direction and filled with plio quaternary rocks structural and palaeomagnetic data indicate that the first system originally had a north south trend and then bodily rotated anticlockwise to its present orientation before the end of the miocene both the orientations and the structural patterns of these cross cutting rift systems suggest that they resulted from two different and successive tectonic regimes regional geology suggests that the generative regime of the older system was characterized by north south compression and related to the palaeotectonic evolution of southwestern anatolia whereas that of the younger system is characterized by north south extension and relates to the neotectonic evolution of this region this inference contradicts at least in southwestern anatolia some recent claims that the extensional tectonics and the related rift formation in the aegean region began in the early miocene with the alleged demise of the compressional palaeotectonics during the late oligocene but is consistent with older views that placed the onset of north south extension into the later middle miocene the formation of the aegean sea seems to be the result of these two complicated and contrasting succesive tectonic regimes that have affected this region since middle miocene times

numerical modeling of the mount steller landslide flow history and of the generated long period seismic waves the rock ice avalanche that occurred in 2005 on mount steller alaska and the resulting long period seismic waves have been simulated for different avalanche scenarios i e flow histories with and without erosion processes taken into account this 40 60 mm3 avalanche traveled about 10 km down the slope mainly on top of a glacier eroding a significant amount of ice it was recorded by 7 broadband seismic stations the simulations were compared with the recorded long period seismic signal and with the inverted flow history the results show that when erosion processes are taken into account the simulations reproduce the observed signal at all the stations over a wide range of azimuths and source station distances 37 623 km this comparison makes it possible to constrain the rheological parameters involved which should help constrain the volume of eroded material because landslides are continuously recorded by seismic networks this method could significantly broaden quantitative insights into natural flow dynamics

landslide seismic signal recognition and mobility for an earthquake induced rockslide in tsaoling taiwan abstract landslide seismic signal processing and the newmark s sliding block analysis are used in this research to analyze the initiation time and mobility of the tsaoling rockslide triggered by the 1999 chi chi earthquake in central taiwan a new technique the time frequency spectrum analysis is employed to identify the rockslide initiation and landing times from four real time seismic records of strong ground motion stations the results suggest that higher frequencies ranging from 30 to 70 hz correspond to the rockslide initiation and sliding process which are opposed to the low signal frequency of earthquake the landslide began at 32 5 s the sliding block sped up at 37 5 s and impacted on the opposite riverbank at 76 s on the seismic time record the mobile scenario of tsaoling rockslide induced by chi chi earthquake is simulated using newmark s sliding block analysis the maximum sliding velocity reaches approximately 75 1 m s despite being a simple conceptual model the newmark s sliding block analysis provides consistent results with the real time seismic signal analysis and details of the rockslide kinematics

detection of landslides and submarine slumps using broadband seismic networks 1 we detected 52 seismic events associated with landslides and submarine slumps on 8 august 2009 when typhoon morakot hit taiwan these events were neither felt nor reported because their seismic energy was primarily in the long period band 20 50 s most of these events were located in mountain areas where the accumulated rainfall was extremely high though some were found offshore southern taiwan among all events the fatal landslide earthquake was located at hsiaolin village where 474 people were buried inversion modelling of the seismic waveforms generated by the hsiaolin landslide shows that the seismic source was represented by single force consistent with downhill sliding some offshore seismic events indicate that submarine slumps probably occurred along submarine canyons and steep slopes our study shows that broadband seismic monitoring can be used to issue early warnings for mitigating disasters generated by inland and offshore landslides

dynamics of the bingham canyon rock avalanches utah usa resolved from topographic seismic and infrasound data the 2013 bingham canyon mine rock avalanches represent one of the largest cumulative landslide events in recorded u s history and provide a unique opportunity to test remote analysis techniques for landslide characterization here we combine aerial photogrammetry surveying topographic reconstruction numerical runout modeling and analysis of broadband seismic and infrasound data to extract salient details of the dynamics and evolution of the multi phase landslide event our results reveal a cumulative intact rock source volume of 52 mm3 which mobilized in two main rock avalanche phases separated by 1 5 h we estimate the first rock avalanche had 1 5 2 times greater volume than the second each failure initiated by sliding along a gently dipping 21 highly persistent basal fault before transitioning to a rock avalanche and spilling into the inner pit the trajectory and duration of the two rock avalanches were reconstructed using runout modeling and independent force history inversion of intermediate period 10 50 s seismic data intermediate and shorter period 1 50 s seismic data were sensitive to intervals of mass redirection and constrained finer details of the individual slide dynamics back projecting short period 0 2 1 s seismic energy we located the two rock avalanches within 2 and 4 km of the mine further analysis of infrasound and seismic data revealed that the cumulative event included an additional 11 smaller landslides volumes 104 105 m3 and that a trailing signal following the second rock avalanche may result from an air coupled rayleigh wave our results demonstrate new and refined techniques for detailed remote characterization of the dynamics and evolution of large landslides

a numerical characterization workflow for assessing the strength and failure modes of heterogeneous oil sands understanding the strength and failure modes of overburden and reservoir are critical components in safety assessments for oil sands surface mining and in situ thermal recovery operations currentl

entrainment of bed material by earth surface mass flows review and reformulation of depth integrated theory earth surface mass flows such as debris flows rock avalanches and dam break floods can grow greatly in size and destructive potential by entraining bed material they encounter increasing use of depth integrated mass and momentum conservation equations to model these erosive flows motivates a review of the underlying theory our review indicates that many existing models apply depth integrated conservation principles incorrectly leading to spurious inferences about the role of mass and momentum exchanges at flow bed boundaries model discrepancies can be rectified by analyzing conservation of mass and momentum in a two layer system consisting of amoving upper layer and static lower layer our analysis shows that erosion or deposition rates at the interface between layers must in general satisfy three jump conditions these conditions impose constraints on valid erosion formulas and they help determine the correct forms of depth integrated conservation equations two of the three jump conditions are closely analogous to rankine hugoniot conditions that describe the behavior of shocks in compressible gasses and the third jump condition describes shear traction discontinuities that necessarily exist across eroding boundaries grain fluid mixtures commonly behave as compressible materials as they undergo entrainment because changes in bulk density occur as the mixtures mobilize and merge with an overriding flow if no bulk density change occurs then only the shear traction jump condition applies even for this special case however accurate formulation of depth integrated momentum equations requires a clear distinction between boundary shear tractions that exist in the presence or absence of bed erosion

pore fluid chemistry from the second gas hydrate drilling expedition in the ulleung basin ubgh2 source mechanisms and consequences of fluid freshening in the central part of the ulleung basin east sea during the second gas hydrate drilling expedition in the ulleung basin ubgh2 pore fluids were collected from sites that sampled sediments from the continental slope to the basin center and included locations within and outside seismic identified chimney like features at five non chimney sites established during the ubgh2 discrete excursions to low cl concentrations within the gas hydrate occurrence zone ghoz are associated with water enriched in d and 18o as expected from gas hydrate dissociation during core recovery estimates of gas hydrate saturation values sh based on cl and d values are in good agreement and show that when gas hydrate occurs in discrete horizons or within strata bound fractures throughout the ghoz it occupies 5 65 of the pore space fluids recovered from three sites characterized by seismic inferred chimneys show massive hydrate accumulation near the seafloor accompanied by the formation of shallow cl rich brines with d and 18o values lower than seawater chemical and isotopic data from fluids sampled at all drilled sites reveal significant fluid freshening below the gas hydrate stability zone ghsz the distribution of cl k and d indicate that the observed freshening is predominantly caused by clay mineral dehydration illitization previously reported heat flow values in the center of the basin indicate that the sediments deeper than 800 mbsf meter below seafloor are warm enough to expect clay diagenesis with the onset of smectite to illite transformation source fluid temperatures 70 c are confirmed through the use of na li and mg2 li geothermometry based on these observations we propose the following scenario for the evolution of formation fluids in the ulleung basin where high formation temperatures and rapid sedimentation at the basin center led to sediment compaction and clay dehydration reactions that result in fluid overpressures and associated fracturing of the formation sediment fractures and fluid possible gas migration in the chimney features imaged in seismic records are consistent with our postulated upward transport of fluids from 800 m depth though the ghsz and to the seafloor

active fault segmentation of the civril graben system and surface rupture of the 1 october 1995 dinar earthquake mw 6 2 southwestern anatolia turkey abstract the civril graben system cgs is one of the important tectonic structures developed within the western anatolia extensional tectonic regime the cgs has an arcuate geometry looking south and comprises two main geometric sections of the nw striking dinar graben and the ne striking baklan graben with a total length of 100 km the main faults limit the north edge of the cgs while the south edge is bounded by their antithetic structures the northern boundary structures of the graben comprise two main fault segments of dinar and civril graben fill is plio quaternary lacustrine fluvial sediments with late pleistocene holocene flood plain lacustrine marsh and alluvial fan sediments historical records and destructive earthquakes occurred in the last century indicate the region is one of the significant seismogenic zones the last destructive earthquake in the graben was the 1995 dinar earthquake mw 6 2 which caused approximately 10 km long surface rupture on the kizilli segment of the dinar fault field based geological mapping and structural geology in this study and available seismic and paleoseismological data reveal that the other sub segments of the dinar and civril faults which have not ruptured in the last 150 years have the potential to produce earthquakes with mw 6 0 and larger the paleoseismic rate is assessed to be 1 mm year for the kizilli segment while the geologically long term slip rate range is calculated to be 0 27 0 05 mm year

slope instabilities in dolomieu crater reunion island from seismic signals to rockfall characteristics 1 the seismic signals of hundreds of rockfalls within dolomieu crater piton de la fournaise volcano reunion island have been analyzed to investigate a possible link between physical rockfall generating processes and associated seismic signal features moreover indirect observation of rockfalls via the seismic signals they generate can provide useful data for studying volcanoes and the temporal variations of their structure an increase in the number of rockfall events and their volumes might be an indicator of structural weakness and deformation of the volcano associated with potential eruptive activity the study focuses on a 10 month period following the 6 april 2007 crater floor collapse within dolomieu crater from may 2007 to february 2008 for granular flows a scaling law is revealed between seismic energy and signal duration a semiempirical approach based on both analytical analysis and numerical simulation of these flows shows that a similar scaling law exists between the difference of potential energy computed for an event and its propagation times and also emphasizes the effect of local topography on this scaling law simulated and observed data were compared to evaluate the proportion of potential energy dissipated in the form of seismic waves and confirm a direct link between the seismic energy and potential energy of a given granular flow the mean ratio of seismic to potential energy is of the order of 10 4 comparable to the range of values observed in previous studies a simple method based on these ratios is proposed to estimate the volumes of rockfalls from their seismic signal observed seismic energy and the frequency of rockfalls decreased at the beginning of the studied period and reached a stable level in july thus suggesting a postcollapse relaxation time of dolomieu crater structure of about 2 months from seismic signal analysis which is confirmed by deformation data the total rockfall volume over the study period is estimated to be 1 85 mm3

seismic monitoring of sechilienne rockslide french alps analysis of seismic signals and their correlation with rainfalls 1 in the french alps sechilienne rockslide is one of the natural phenomena that presents one of the highest levels of risk in terms of socioeconomical outcomes this rockslide has been active for a few decades and has been instrumented since 1985 the current very active volume of this rockslide is estimated to be up to 5 million m3 located on the border of a slowly moving mass reaching 50 100 million m3 the velocity of the most active zone reached 1 4 m yr in 2008 about twice the value of 2000 a seismic network was installed on this rockslide in may 2007 to supplement the monitoring system it has now recorded several thousand events mostly rockfalls but also hundreds of local and regional earthquakes which can be distinguished and classified from their signal characteristics rockfalls and microseismicity which occur in bursts of activity are found to be weakly but significantly correlated with rainfall rockfall occurrence increases linearly with precipitation with however strong fluctuations of the numbers of rockfalls per day for the same rainfall intensity no threshold was found for rainfall triggering with even 1 mm of rain being enough to trigger rockfalls rockfall activity starts almost immediately during a rainfall episode and lasts for several days after the rainfall rain also induces strong accelerations of the rockslide movement which also start quasi instantaneously and last for about a month

dynamic landslide processes revealed by broadband seismic records 1 we use broadband seismic recordings to trace the dynamic process of the deep seated akatani landslide that occurred on the kii peninsula japan which is one of the best recorded large slope failures combining analyses of the seismic records with precise topographic surveys done before and after the event we can resolve a detailed time history of the mass movement during 50 s of the large landslide we observe a smooth initiation acceleration with changes in basal friction and reversal of the momentum when the mass collides with the opposite valley wall of particular importance is the determination of the dynamic friction during the landslide the coefficient of friction is estimated to be 0 56 at the beginning of the event and drops to 0 38 for most of the sliding the change in the frictional level on the sliding surface may be due to liquefaction or breaking of rough patches and contributes to the extended propagation of the large landslide

seismic recordings of landslides caused by typhoon talas 2011 japan 1 large deep seated landslides occurred in nara wakayama and mie prefectures of western japan when typhoon talas passed through the region on september 3 4 2011 signals of large landslides have been recorded by seismic networks around the world and overall force estimates have been previously determined for large landslides using long period waves this study focuses on the high frequency waveforms and presents signals of 18 landslides caused by typhoon talas 2011 the location of the landslides can be determined by a seismological back projection technique and these locations correlate with the observed surface features we have found that the volumes of the landslide correlated with an energy parameter derived from the seismic records

experimental study of debris flow entrainment over stepped gradient beds incorporating bed sediment porosity abstract the incorporation of bed sediment by a natural debris flow can cause significant growth in its size and destructive potential in this study the erosion features of debris flows in channels with stepped gradient beds were determined based on field observations and flume experiments field investigations revealed that channel sections with abrupt bed slope variations were eroded more intensely than others a series of small scale flume tests were conducted to study the pore pressure variations in erodible bed sediment and the basal entrainment behaviour of debris flows in channels with stepped gradients reference tests on a uniform bed slope demonstrate that inflection points in the bed longitudinal profile greatly alter the debris mixture flow pattern and accelerate entrainment pore pressure generation in the bed sediment supports debris flow entrainment by reducing basal friction peak pore pressures at concave sites were approximately two times higher than those observed at convex sites likely due to large changes in debris flow dynamics and intense interactions between the flow mixture and bed sediment low bed sediment porosities will increase the interlocking of grain particles promote the formation of clusters and enhance the strength of the grain skeleton suppressing basal entrainment in the flume tests lower peak pore pressures were observed as bed porosity decreased possibly due to fewer connecting channels for pore fluid pressure to transmit in the compacted bed sediment dimensionless analysis indicates that pore pressure fluctuations in the bed sediment were mainly generated by the overriding debris flow a new entrainment formula of debris flow over stepped gradient beds is proposed based on flume tests and theoretical analyses which may aid future debris flow modelling and hazard assessments

superimposed basin formation during neogene quaternary extensional tectonics in sw anatolia turkey insights from the kinematics of the dinar fault zone abstract in the extensional province of sw anatolia the cross cutting relationship between the nw and ne oriented neogene and quaternary basins is an ongoing debate in the understanding of the tectonic evolution of this area in order to contribute to this issue we carried out a structural and kinematic study along the seismogenic nw trending dinar fault zone dfz this structure was initially controlled by the sedimentary and tectonic evolution of the ne oriented neogene baklan acigol and burdur basins and later by the nw oriented quaternary dinar basin on the basis of 1000 structural and kinematic data in conjunction with basin stratigraphy the dfz can be divided into three almost parallel and continuous bands that are a the hangingwall where quaternary sediments are deformed by normal faults with mechanical striations b the inner zone corresponding to the present dinar fault scarp where nw trending normal faults with mechanical striations are dominant and c the outer zone located in the footwall of the structure comprising the area between the fault scarp and undeformed bedrock where faults exhibit variable orientation and kinematics from strike slip to normal dip slip these kinematics are mainly indicated by calcite shear veins and superimposed mechanical striations respectively this suggests that the dfz changed kinematics over time i e the dfz initiated as dominant dextral strike slip to oblique slip fault system and continued with a dominant normal movement therefore we hypothesize that the nw trending dfz was initially a transfer zone during the late miocene pliocene coeval to the sedimentary and structural evolution of the ne trending baklan acigol and burdur basins during the quaternary the dfz representing an already weakened crustal sector played the role of a normal fault system providing the accommodation space for the quaternary dinar basin hydrothermal circulation and volcanism at ne nw trending faults intersection implies structurally driven conduits channeling fluids from depth to surface

source inversion of the october 1 1995 dinar earthquake ms 6 1 a rupture model with implications for seismotectonics in sw turkey abstract an earthquake of ms 6 1 devastated the town of dinar sw turkey population 35 000 on october 1 1995 killing 90 people and destroying 30 of the town the earthquake generated complex body waveforms varying with azimuth at teleseismic distances the method of complex body waveform inversion developed by kikuchi and kanamori 1991 was used to infer a source process for the earthquake two subevents were necessary to explain the observed seismic records the inversion result suggests that the dinar earthquake initiated at the se end of the dinar fault with a subevent of seismic moment mo 0 5 1018 n m six seconds later the second subevent took place about 10 km to the northwest of the first subevent with a seismic moment a few times larger than the first the cmt depths of the first and second subevents were found to be 10 and 15 km respectively both subevents had a predominantly normal faulting mechanism with slip vectors oriented ne sw showing good agreement with the velocity vectors obtained from the recent slr and gps studies as well as with the regional stress orientation obtained from geological data the main shock was preceded by foreshock activity concentrated at the se end of the dinar fault where the first subevent took place while the aftershock activity was concentrated in the vicinity of the second subevent the spatial distribution of the foreshock and the aftershock activities and the locations of the subevents suggest that the first subevent broke an asperity and the second subevent broke a barrier on the fault following the definition by aki 1984 of an asperity and barrier earthquake model about 10 km of surface ruptures were associated with the earthquake while the estimates yield a rupture length of 25 km the calculated source parameters of the subevents and their locations suggest that the surface ruptures were probably associated with the first subevent the estimates also show that the rupture zones of the two subevents overlapped where the maximum vertical displacement was observed

deformation of western turkey from a combination of permanent and campaign gps data limits to block like behavior 1 we present a new geodetic velocity field covering western turkey south of the north anatolian fault our velocity field is derived from a combination of continuously recording gps stations operating since 2003 survey type gps measurements carried out in the period 1997 2005 and velocities from reilinger et al 2006 the velocity field indicates that western turkey currently undergoes extension whose rate increases from the anatolia plateau to the aegean coast the overall extension in westernmost turkey is about 20 mm yr making it one of the fastest areas of continental extension in the world we test whether the observed deformation is better represented by the rotation of crustal blocks or by more distributed deformation while no deformation is detected in the central anatolian plateau we observe a deformation field west of the plateau that cannot be explained by block models unless the blocks are so small as to be essentially indistinguishable from a continuum although concentration of strain rates up to 140 nstrain yr are found across the major grabens strain rates above 50 nstrain yr are found throughout western turkey the distributions of topography and crustal thickness in western turkey agree with the distributions expected if the crust there had a constant thickness at 5 ma equal to that of the present central anatolian plateau and had subsequently been thinned at the present day distribution of strain rates our results therefore suggest that extensional strain affects the whole continental lithosphere of western turkey rather than being restricted to a small number of block boundaries

catastrophic landslide induced by typhoon morakot shiaolin taiwan abstract typhoon morakot induced the catastrophic and deadly shiaolin landslide in southern taiwan on 9 august 2009 resulting in more than 400 casualties we undertook a geological and geomorphological investigation with the aim of reconstructing the events leading up to this landslide and to clarify factors that contributed to its development cumulative rainfall reached up to 1676 5 mm in about three days under the influence of the typhoon and the shiaolin landslide with a volume of 25 106 m3 occurred one day after the peak in rainfall intensity the landslide occurred on a dip slope overlying late miocene to early pliocene sedimentary rocks consisting of silty shale massive mudstone and sandstone it started as a rockslide in the upper third of the landslide area and transformed into a rock avalanche that crossed a series of terraces and displaced or buried the village below it buried the riverbed of the chishan river and ran up the opposite slope creating a landslide dam 60 m high which was breached about 1 h and 24 min later flooding the village the velocity of the landslide is estimated to have been 20 4 to 33 7 m s 1 and its apparent friction angle was 14 which indicates its high mobility the detachments in the source area consist of combinations of bedding planes and joints or faults the landslide was preceded by gravitational deformation which appeared as hummocky landforms before the landslide and as buckle folds exposed after the event the landslide deposits consist of fragments of mudstone shale and sandstone as well as clayey material at its base this clayey material consisting of illite chlorite quartz feldspar and calcite is assumed to have strongly influenced the long rapid runout

fault block rotations at the edge of a zone of continental extension southwest turkey the ne sw trending burdur acigol and baklan basins of southwest turkey are bounded by normal faults which became active in quaternary times prior to this a more widely spaced system of pliocene basins had existed each of the quaternary basins has a half graben geometry with a major nw dipping fault on its southeast side previous studies of the 1971 burdur earthquake caused by movement on the fault bounding the burdur basin have shown this fault to flatten slightly at depth deformation in the hangingwall of the fault controlling the pliocene basin in the burdur region suggests a planar fault geometry it is suggested that the pliocene fault rotated to its present shallow orientation then became inactive and acted as a detachment at depth for the more recent quaternary fault quaternary faults bounding the burdur acigol and baklan basins have a sinistral strike slip component with slip vectors indicating extension in an nw se direction this is at variance with regional n s extension in western turkey a solution for this contrast is found by invoking block rotations about vertical axes in a deforming zone between the rapidly extending aegean region to the west and the stable unstretched anatolian plateau to the east

source parameters of the 1 october 1995 dinar turkey earthquake from sar interferometry and seismic bodywave modelling abstract the 1 october 1995 m s 6 1 dinar earthquake ruptured a 10 km section of the nw se dinar civril fault there are discrepancies between the published source parameters from seismic data with seismic moments in disagreement by over a factor of two we use both sar interferometry and seismic bodywave modelling to determine earthquake source parameters an interferogram generated from ers 1 2 sar imagery spanning the event and separated by 5 months is used to derive source parameters by a downhill simplex inversion with multiple monte carlo restarts we model the displacements in the satellite line of sight initially using uniform slip on a rectangular dislocation in an elastic half space the resultant model fault plane agrees in strike and location with the observed surface break but systematic residuals exist in the line of sight deformation field resulting in a r m s residual of 20 mm in the interferogram the residuals are reduced if the depth distribution of slip is allowed to vary spatially in four segments along a continuous fault plane our best fitting solution with a r m s misfit of 8 mm reveals two distinct areas of slip on the fault plane strike 145 dip 49 rake 270 a main rupture slipping by 1 44 m between depths of 1 and 8 km becoming deeper to the se and matching the observed surface rupture and an along strike continuation to the nw of the same fault plane but between depths of 8 and 13 km and not associated with a surface break the total geodetic moment 4 5 0 1 10 18 nm is more than twice as large as published seismic moments based on the inversion of p waveforms alone but close to the harvard cmt moment 4 7 10 18 nm we use sh waveforms in addition to the p waves used previously to determine an alternative seismic source mechanism sh waves constrain the depth to be shallower than solutions based on p waves alone agreeing with the depths from the interferometric inversion and resulting in a larger moment 3 1 0 4 10 18 nm than the previous bodywave estimates 2 2 1 10 18 nm the cmt moment reduces in magnitude to a similar size 3 3 10 18 nm if the centroid depth and fault dip are constrained to the values determined from bodywave modelling and interferometry thus the geodetic moment is 40 bigger than the moment determined from seismology

identification of co seismic ground motion due to fracturing and impact of the tsaoling landslide taiwan abstract earthquakes can generate seismic disturbances that propagate vast distances and trigger landslides that can achieve high speeds it remains difficult to identify the co seismic ground motion of these landslides and their triggering earthquakes in this paper we report on the analysis of co seismic ground motions generated by the initiating fracture and deposition impact of the tsaoling landslide the landslide with a source volume of 125 10 6 m 3 was triggered by the 1999 chi chi earthquake in taiwan the ground motion was recorded by a strong ground motion station chy080 near the scar area the polarization of the seismic waves indicates that the peak acceleration was parallel to the dip direction modified ensemble empirical mode decomposition eemd with additional clustering analysis was applied to decompose the seismic signals two instances were found in the seismic records of a series of peculiar wave packets with the first being associated with the landslide initiation and the second the landslide impact on the deposit valley to confirm the first landslide breakage the decomposed signals were compared with the predictions of the analytic elastic wave model and newmark analysis the landslide impact was verified with a computational fluid dynamic simulation comparison between the eemd decomposed signals elastic wave theory newmark rigid body analysis and numerical simulation demonstrates the claimed landslide motion

a physical model for seismic noise generation from sediment transport in rivers measuring sediment flux in rivers remains a significant problem in studies of landscape evolution recent studies suggest that observations of seismic noise near rivers can help provide such measurements but the lack of models linking observed seismic quantities to sediment flux has prevented the method from being used here we develop a forward model to describe the seismic noise induced by the transport of sediment in rivers the model provides an expression for the power spectral density psd of the rayleigh waves generated by impulsive impacts from saltating particles which scales linearly with the number of particles of a given size and the square of the linear momentum after incorporating expressions for the impact velocity and rate of impacts for fluvially transported sediment we observe that the seismic noise psd is strongly dependent on the sediment size such that good constraints on grain size distribution are needed for reliable estimates of sediment flux based on seismic noise observations the model predictions for the psd are consistent with recent measurements and based on these data a first attempt at inverting seismic noise for the sediment flux is provided

active faults and evolving strike slip basins in the marmara sea northwest turkey a multichannel seismic reflection study abstract the north anatolian fault is a 1200 km long transform fault forming the boundary between the anatolian and eurasian plates near its western end it strikes through the marmara sea and is responsible for the creation of three deep marine depressions the north anatolian fault system and the linked basins in the eastern marmara sea were studied using newly acquired multi channel seismic reflection data in the marmara sea the north anatolian fault consists of a main strand and a few subsidiary branches the main strand is made up of the ganos 15 km long central marmara 105 km and north boundary 45 km fault segments the north boundary fault joins in the east to the izmit segment which was ruptured during the m s 7 4 earthquake on 17 8 1999 the north boundary fault is highly oblique to the regional displacement vector which results in the generation of a symmetrical fault wedge basin this cinarcik basin is a wedge shaped deep marine depression south of istanbul it is about 50 km long up to 20 km wide and 1250 m deep and is filled with pliocene to quaternary sediments over 3 km thick the north boundary fault joins in the west to the transpressional central marmara fault around the restraining segment boundary the syntransform sediments are being deformed into a large anticlinorium the cinarcik basin started to form when the westward propagating north anatolian fault intersected a northwest trending pre existing fault zone during the pliocene and bifurcated into nw and sw trending segments forming a transform transform transform type triple junction dextral strike slip movement along the arms of the triple junction led to the development of the cinarcik basin the present fault geometry in the marmara region was achieved later during the mid pliocene following the termination of the triple junction geometry south of the main north anatolian fault system there is a second active strike slip fault in the marmara sea made up of several segments a highly asymmetrical fault bend basin comprising pliocene quaternary sediments over 2 5 km thick is forming along a releasing fault segment of this south boundary fault system

comprehensive analysis of the local seismic response in the complex buyukcekmece landslide area turkey by engineering geological and numerical modelling multi risk management requires a strong comprehension of possible effects induced by natural hazardous events in this regard landslides triggering due to earthquakes results from complex interactions between seismic waves and slopes multidisciplinary approaches can significantly contribute to better understand such interactions the large buyukcekmece landslide about 1500 m wide and 1830 m long located in turkey avcilar peninsula about 15 km northward from the north anatolian fault zone nafz was selected as case study in the framework of the european project marsite marmara supersite new directions in seismic hazard assessment through focused earth observation in the marmara supersite the avcilar area was recently affected by the 17th august 1999 mw 7 4 kocaeli and by the 12th november mw 7 2 duzce earthquakes the buyukcekmece landslide involves upper oligocene to lower miocene deposits consisting of silty clays tuffs and sands no earthquake induced re activations are testified so far but the landslide area was interested by a very intense urbanization during the last decade a detailed engineering geological model for the local seismic response of the buyukcekmece landslide slope was constructed based on geophysical measurements data from a multisensor in hole monitoring system and stress strain numerical modelling several tens of earthquakes were recorded from october 2014 to may 2015 in the landslide site by considering in hole and surface data the reliability of the local seismic response obtained by numerical modelling respect to the empirically derived one was checked in terms of both site to reference spectral ratios and transfer function between surface and downhole sites inside the landslide mass the 2d numerical amplification functions confirm that the local seismic response is a consequence of the complex geological setting of the landslide slope while no relevant amplification effects can be referred to topographic features based on these results the interaction between seismic waves and the buyukcekmece landslide slope cannot be neglected to evaluate the possibility of future landslide re activations

numerical modeling of landquakes the thurwieser landslide that occurred in italy in 2004 and the seismic waves it generated have been simulated and compared to the seismic signal recorded a few tens of kilometers from the landslide source i e landquake the main features of the low frequency seismic signal are reproduced by the simulation topography effects on the flowing mass have a major impact on the generated seismic signal whereas they weakly affect low frequency wave propagation simulation of the seismic signal makes it possible to discriminate between possible alternative scenarios for flow dynamics and to provide first estimates of the rheological parameters during the flow as landquakes are continuously recorded by seismic networks our results provide a new way to collect data on the dynamics and rheology of natural flows

global positioning system constraints on plate kinematics and dynamics in the eastern mediterranean and caucasus we present and interpret global positioning system gps measurements of crustal motions for the period 1988 1997 at 189 sites extending east west from the caucasus mountains to the adriatic sea and north south from the southern edge of the eurasian plate to the northern edge of the african plate sites on the northern arabian platform move 18 2 mm yr at n25 5 w relative to eurasia less than the nuvel 1a circuit closure rate 25 1 mm yr at n21 7 w preliminary motion estimates 1994 1997 for stations located in egypt on the northeastern part of africa show northward motion at 5 6 2 mm yr also slower than nuvel ia estimates 10 1 mm yr at n2 4 e eastern turkey is characterized by distributed deformation while central turkey is characterized by coherent plate motion internal deformation of 2 mm yr involving westward displacement and counterclockwise rotation of the anatolian plate the anatolian plate is de coupled from eurasia along the right lateral strike slip north anatolian fault naf we derive a best fitting euler vector for anatolia eurasia motion of 30 7 0 8 n 32 6 0 4 e 1 2 0 1 myr the euler vector gives an upper bound for naf slip rate of 24 1 mm yr we determine a preliminary gps arabia anatolia euler vector of 32 9 1 2 n 40 3 1 1 e 0 8 0 2 myr and an upper bound on left lateral slip on the east anatolian fault eaf of 9 1 mm yr the central and southern aegean is characterized by coherent motion internal deformation of 2 mm yr toward the sw at 30 1 mm yr relative to eurasia stations in the se aegean deviate significantly from the overall motion of the southern aegean showing increasing velocities toward the trench and reaching 10 1 mm yr relative to the southern aegean as a whole

gps constraints on continental deformation in the africa arabia eurasia continental collision zone and implications for the dynamics of plate interactions 1 the gps derived velocity field 1988 2005 for the zone of interaction of the arabian african nubian somalian and eurasian plates indicates counterclockwise rotation of a broad area of the earth s surface including the arabian plate adjacent parts of the zagros and central iran turkey and the aegean peloponnesus relative to eurasia at rates in the range of 20 30 mm yr this relatively rapid motion occurs within the framework of the slow moving 5 mm yr relative motions eurasian nubian and somalian plates the circulatory pattern of motion increases in rate toward the hellenic trench system we develop an elastic block model to constrain present day plate motions relative euler vectors regional deformation within the interplate zone and slip rates for major faults substantial areas of continental lithosphere within the region of plate interaction show coherent motion with internal deformations below 1 2 mm yr including central and eastern anatolia turkey the southwestern aegean peloponnesus the lesser caucasus and central iran geodetic slip rates for major block bounding structures are mostly comparable to geologic rates estimated for the most recent geological period 3 5 myr we find that the convergence of arabia with eurasia is accommodated in large part by lateral transport within the interior part of the collision zone and lithospheric shortening along the caucasus and zagros mountain belts around the periphery of the collision zone in addition we find that the principal boundary between the westerly moving anatolian plate and arabia east anatolian fault is presently characterized by pure left lateral strike slip with no fault normal convergence this implies that extrusion is not presently inducing westward motion of anatolia on the basis of the observed kinematics we hypothesize that deformation in the africa arabia eurasia collision zone is driven in large part by rollback of the subducting african lithosphere beneath the hellenic and cyprus trenches aided by slab pull on the southeastern side of the subducting arabian plate along the makran subduction zone we further suggest that the separation of arabia from africa is a response to plate motions induced by active subduction

spectral analysis of seismic noise induced by rivers a new tool to monitor spatiotemporal changes in stream hydrodynamics to 20 db relative to m s 2 hz for all the stations located along a steep 30 km long narrow and deeply incised channel of the trisuli river a major trans himalayan river the early summer increase in high frequency energy is modulated by a 24 h periodicity where the minimum of seismic noise level is reached around noon and the maximum is reached late in the evening a detailed study of seismic noise amplitude reveals a clear correlation with both regional meteorological and hydrological data along the trisuli river seasonal increase in ambient noise coincides with the strong monsoon rainfall and a period of rapid melting of snow and ice in the high elevations the observed 24 h cyclicity is consistent with the daily fluctuation of the precipitation and river discharge in the region river induced seismic noise is partly generated by stream turbulence but this mechanism fails to explain the observed clockwise hysteresis of seismic noise amplitude versus water level this pattern is better explained if a significant part of the observed seismic noise is caused by ground vibrations generated by bed load transport this points out the potential of using background seismic noise to quantify in continuous river bed load and monitor its spatial variations which remain difficult with classical approaches

remote sensing and seismic data integration for the characterization of a rock slide and an artificially triggered rock fall abstract on may 5th 2013 a planar rock slide 450 m3 occurred in the village of la riba ne spain which forced the closure of the road c 240z for 6 months this slide left a hanging block 130 m3 suspended on the slope forcing a controlled blasting followed by rock slope stabilization works the volume of rock displaced during the both events was deduced from lidar and photogrammetry data following two approaches subtracting pre and post event data and reconstructing the volume by fitting planes on the structural surfaces after a structural analysis of the slope information about the natural rock slide was obtained from the records of two permanent broadband seismic stations located 10 km from the site from these seismic records the existence of a rock slide was confirmed and its time of occurrence was determined information that would be otherwise unknown in addition despite the small volume displaced during the event its location was deduced from a single seismic station analysis the blasting process was recorded with two high definition hd video cameras and by two temporary seismic stations deployed close to the site 10 km partially because only a part of the released energy is transmitted into the ground as seismic energy and partially because the recorded seismic signal is highly dependent on the event characteristics and the geotechnical conditions of the ground materials nevertheless seismic data is very well suited to detect and characterize in detail both rockfall events of different nature and size merging and integrating remote sensing techniques such as lidar or photogrammetry with seismic measurements should allow the implementation of rockfall early warning systems

kinematic development and paleostress analysis of the denizli basin western turkey implications of spatial variation of relative paleostress magnitudes and orientations paleostress orientations and relative paleostress magnitudes stress ratios determined by using the reduced stress concept are used to improve the understanding of the kinematic characteristics of the denizli basin two different dominant extension directions were determined using fault slip data and travertine fissure orientations in addition to their stratigraphically coeval occurrence the almost exact fit of the s2 and s3 orientations for the ne sw and nw se extension directions in the late miocene to recent units indicate that these two extension directions are a manifestation of stress permutations in the region and are contemporaneous this relationship is also demonstrated by the presence of actively developing ne sw and nw se elongated grabens developed as the result of ne sw and nw se directed extension in the region moreover stress ratios plots indicate the presence of a zone of major stress ratio changes that are attributed to the interference of graben systems in the region it is concluded that the plotting of stress orientations and distribution of stress ratios is a useful tool for detecting major differences in stress magnitudes over an area the boundaries of which may indicate important subsurface structures that cannot be observed on the surface q 2005 elsevier ltd all rights reserved

sedimentation of the neogene recent alasehir gediz continental graben system used to test alternative tectonic models for western aegean turkey abstract the alasehir gediz graben exemplifies clastic sedimentation in a long lived continental half graben in a semi arid setting developed within relatively incompetent metamorphic rocks early miocene to recent rift related sediments are exhumed on both flanks of the graben allowing detailed three dimensional study during the early miocene small fan delta lobes were shed northwards from the rugged menderes metamorphic massif into a bordering lacustrine basin during early to mid miocene time large alluvial fans prograded northwards into this basin through drainage to the aegean sea was established as the basin widened and filled discrete lobes of coarse alluvial fan sediments of latest miocene pliocene age also shedding northwards are likely to have been climatically influenced quaternary alluvium party infills the modern alasehir rift basin the sedimentary information can be used to test two alternative tectonic models for the alasehir graben in the first model an e w graben bounded by high angle faults was active during latest miocene recent time whereas earlier miocene sedimentation was controlled by n s faulting related to a n s compressional stress regime in the second hypothesis the alasehir graben was initiated much earlier in the early miocene and was then either continuously or episodically active until recent our results especially facies and palaeocurrent data from alluvial sediments indicate that clastic sedimentation was controlled by mainly e w faulting in a n s stress regime assuming the early miocene clastic sediments are correctly dated this supports the second long lived extension model however rather than steady state extension for ca 15 ma the sedimentary evidence and regional context are consistent with a pulsed extension model whereby initial early to mid miocene extension and related clastic sedimentation was followed by a second phase of extension in latest miocene pliocene time the driving force of initial early miocene extension was probably gravity spreading towards a south aegean subduction zone whereas the inferred second extension pulse is seen as being triggered by westward tectonic escape of anatolia towards the extending aegean back arc region

was the 1899 menderes valley earthquake a double earthquake historical and paleosismological constraints abstract september 20 1899 menderes valley earthquake is the last destroying event in the buyuk menderes graben western turkey just proceeding the installation of the earliest seismograms in the world the previous geological studies revealed that this seismic event of estimated mw 6 5 6 7 caused a surface rupture of 50 km between aydin and kuyucak in the center of the graben based on the extremely different positioning of microseismic epicenter of this event in various historical documents we re evaluated the 1899 earthquake with a rather multidisciplinary perspective quantitative earthquake data including fatalities damage and various types of aids were gathered from daily journals and special commission reports of the time these data are corrected with the population statistics and georeferenced for exact determination of the position of the surface rupture we benefited the verbal description in historical documents and witnesses of elder local people furthermore morphological and palaeoseismological investigations were realized in the eastern part of the graben where surface deformations were made mention in historical documents different ground shake related indicators conformably revealed two distinct geographically separated damage zone one at yenipazar and the other at ortakci in the middle and east of the graben respectively trench studies in the west of the ortakci village indicated evidences of a seismic event presumably the 1899 earthquake with 180 cm vertical displacement bimodal distribution damage unrelated to basement lithology and building types and the incoherence between the total surface rupture length and the observed vertical offset and earthquake intensity lead us to conclude that the 1899 menderes valley earthquake was an earthquake doublet occurred in two neighboring segments in very close temporal proximity