finite faults and inverse theory with applications to the 1979 imperial valley earthquake abstract using a representation theorem from elastodynamics subsurface slip on a known fault is formulated as the solution to an inverse problem in which recorded surface ground motion is the data two methods of solution are presented the least squares method which minimizes the squared differences between theory and data and the constrained least squares method which simultaneously maintains a set of linear inequalities instabilities in the solution are effectively eliminated in both methods and the sensitivity of the solution to small changes in the data is quantitatively stated the inversion methodology is applied to 77 components of near field ground acceleration recorded during the 15 october 1979 imperial valley earthquake the faulting is constrained to propagate bilaterally away from the epicenter at an average velocity of 90 per cent of the shear wave speed on a vertical fault plane extending from the surface to 10 km depth inequality constraints are used to keep the faulting sequence physically reasonable by maintaining right lateral motion and positive slip velocity the preferred solution is stable and provides a good fit to the data it is also realistic and consistent with observed surface offsets and independent estimates of seismic moment

palaeoclimate change recorded in upper cretaceous albian cenomanian kazhdumi formation borehole spectral gamma ray logs south pars gas field persian gulf abstract th u and th k data from spectral gamma ray logs obtained from outcrop successions have been used as a rapid and inexpensive proxy for determining possible episodes of humid arid palaeoclimate change such outcrop based measurements have never been tested using spectral gamma ray data obtained from wireline logs in subsurface boreholes th k and th u ratios have traditionally been used to decipher sequence stratigraphic patterns at outcrop and in borehole the possible influence of palaeoclimate on such ratio changes has yet to be proven especially from borehole data in this work we compare borehole derived th k and to a lesser extent th u to palaeoenvironmental changes inferred from palynology and deduce that both sea level and changing hinterland weathering regimes caused discrete fluctuations observed in the spectral gamma ray logs this is the first time such subsurface information has been used in this way interpretation of wireline logs in terms of palaeoclimate as well as sea level may now be considered and the use of such logs in palaeoclimate reconstruction is strengthened

estimation of debris flow triggering rainfall influence of rain gauge density and interpolation methods abstract the forecast of debris flow occurrence relies mainly on empirical rainfall intensity duration thresholds which are based on rain gauge observations this work focuses on the effect of rainfall estimation uncertainty on the estimation of debris flow triggering rainfall events and on the identification of rainfall thresholds for debris flow occurrence specifically the influence of rain gauge network density and the interpolation method on the estimation of debris flow triggering rainfall is investigated these questions are examined using high resolution carefully corrected radar data to represent space time patterns of true precipitation at the debris flow initiation points and in the surrounding area radar rainfall fields are sampled by simulated rain gauge networks stochastically generated with varying rain gauge densities based on these networks rainfall is estimated by using three rainfall interpolation methods nearest neighbor nn inverse distance weighting idw and ordinary kriging ok results show that nn provides the estimates with bias smaller than idw and ok but larger estimation variance overall decrease in gauge density leads to increased underestimation and increased estimation variance of debris flow triggering rainfall rainfall estimation error leads to large underestimation of the intensity duration thresholds however comparison of results shows that no particular benefit in intensity duration threshold estimation is obtained by using approaches that are more complex than the nn method

smooth and rapid slip near the japan trench during the 2011 tohoku oki earthquake revealed by a hybrid back projection method abstract we developed a new back projection method that uses teleseismic p waveforms to integrate the direct p phase with reflected phases from structural discontinuities near the source and used it to estimate the spatiotemporal distribution of the seismic energy release of the 2011 tohoku oki earthquake we projected a normalized cross correlation of observed waveforms with corresponding green s functions onto the seismic source region to obtain a high resolution image of the seismic energy release applying this method to teleseismic p waveform data of the 2011 tohoku oki earthquake we obtained spatiotemporal distributions of seismic energy release for two frequency bands a low frequency dataset and a high frequency dataset we showed that the energy radiated in the dip direction was strongly frequency dependent the area of major high frequency seismic radiation extended only downdip from the hypocenter whereas the area of major low frequency seismic radiation propagated both downdip and updip from the hypocenter we detected a large release of seismic energy near the japan trench in the area of maximum slip which was also the source area of the gigantic tsunami when we used only the low frequency dataset the timing of this large seismic energy release corresponded to an episode of smooth and rapid slip near the japan trench and reflects the strong dependence of the seismic energy distribution obtained on the frequency band of the input waveform dataset the episode of smooth and rapid slip may have been the trigger for a release of roughly all of the accumulated elastic strain in the seismic source region of the 2011 tohoku oki earthquake

convergence rate across the nepal himalaya and interseismic coupling on the main himalayan thrust implications for seismic hazard we document geodetic strain across the nepal himalaya using gps times series from 30 stations in nepal and southern tibet in addition to previously published campaign gps points and leveling data and determine the pattern of interseismic coupling on the main himalayan thrust fault mht the noise on the daily gps positions is modeled as a combination of white and colored noise in order to infer secular velocities at the stations with consistent uncertainties we then locate the pole of rotation of the indian plate in the itrf 2005 reference frame at longitude 1 34 3 31 latitude 51 4 0 3 with an angular velocity of 0 5029 0 0072 myr the pattern of coupling on the mht is computed on a fault dipping 10 to the north and whose strike roughly follows the arcuate shape of the himalaya the model indicates that the mht is locked from the surface to a distance of approximately 100 km down dip corresponding to a depth of 15 to 20 km in map view the transition zone between the locked portion of the mht and the portion which is creeping at the long term slip rate seems to be at the most a few tens of kilometers wide and coincides with the belt of midcrustal microseismicity underneath the himalaya according to a previous study based on thermokinematic modeling of thermochronological and thermobarometric data this transition seems to happen in a zone where the temperature reaches 350 c the convergence between india and south tibet proceeds at a rate of 17 8 0 5 mm yr in central and eastern nepal and 20 5 1 mm yr in western nepal the moment deficit due to locking of the mht in the interseismic period accrues at a rate of 6 6 0 4 10 19 nm yr on the mht underneath nepal for comparison the moment released by the seismicity over the past 500 years including 14 m w 7 earthquakes with moment magnitudes up to 8 5 amounts to only 0 9 10 19 nm yr indicating a large deficit of seismic slip over that period or very infrequent large slow slip events no large slow slip event has been observed however over the 20 years covered by geodetic measurements in the nepal himalaya we discuss the magnitude and return period of m 8 earthquakes required to balance the long term slip budget on the mht

regional stratigraphy of the zagros fold thrust belt of iran and its proforeland evolution the latest neoproterozoic through phanerozoic stratigraphy of the zagros fold thrust belt of iran has been revised in the light of recent investigations the revised stratigraphy consists of four groups of rocks each composed of a number of unconformity bounded megasequences representing various tectonosedimentary settings in the lowest group ranging in age from latest precambrian to devonian the uppermost neoproterozoic to middle cambrian rocks constitute a megasequence of evaporites siliciclastic deposits and interlayered carbonates which were deposited in pull apart basins that developed by the najd strike slip fault system this megasequence is overlain by a second one middle to late cambrian in age which consists of shallow marine siliciclastic and carbonate rocks representing deposition in an epicontinental platform the overlying shales siltstones and partly volcanogenic sandstones of ordovician silurian and devonian age are local remnants of stratigraphic units that were extensively eroded during development of several major unconformities the second group consists of two megasequences one permian and the other triassic composed of widespread transgressive basal siliciclastic rocks and overlying evaporitic carbonates of an equatorial epi pangean very shallow platformal sea the third group is composed of four megasequences formed of shallow and deep water carbonates with some siliciclastic and evaporite deposits which accumulated on a neo tethyan continental shelf during earliest jurassic through late turonian time the fourth group comprises siliciclastic and carbonate deposits of a largely underfilled nw to se trending forward and backward migrating late cretaceous to recent proforeland basin which has evolved as an integral part of the zagros orogen this last group consists of three megasequences ix x and xi with distinctive lateral and vertical facies variations which reflect specific tectonic events megasequence ix comprises uppermost turonian to middle maastrichtian prograding and retrograding siliciclastic and carbonate deposits whose accumulations reflect emplacement obduction of ophiolite slivers and subsequent collisional events in the zagros orogen megasequence x consists of uppermost maastrichtian to upper eocene siliciclastic and carbonate rocks which deposited first progradationally in front of the zagros orogenic wedge with reduced contractional tectonic activity and then retrogradationally due to intensified thrust stacking in the interior parts of the orogen megasequence xi consists of oligocene and lower miocene carbonate strata deposited retrogradationally shortly after a period of intensified late eocene thrust faulting in the deformational wedge and an overlying succession of upward coarsening northeasterly derived siliciclastic deposits of lower miocene to recent age which are composed of erosional byproducts of the southwest vergent zagros thrust sheets

debris flow analyst da a debris flow model considering kinematic uncertainties and using a gis platform abstract although the main driving force of debris flows is simply gravity the dynamic processes are very complex kinematic uncertainties during motion make it difficult to exactly simulate debris flows in traditional numerical simulation models of debris flows the kinematic uncertainties are generally not considered in the lagrangian description in addition the challenge of obtaining accurate simulation parameters further suggests the necessity of probabilistic modeling of debris flows in this study a novel statistical debris flow simulation model debris flow analyst model is proposed in the lagrangian description in which the inherent stochasticity in the motion of a debris flow is described by stochastic differential equations sdes in this model the accelerations of moving debris are calculated by newton s second law and their locations are estimated based on monte carlo simulation according to case studies the proposed model provides results close to the analytical solution in a 1 d simulation of dam breaks in the eulerian description and reduces some numerical oscillations additionally the debris flow analyst model can produce reasonable results based on a single phase rheological model in 2 d simulations of a debris flow in tibet and a flow like landslide triggered by storms on 4 5 november 1993 in hong kong from the theoretical perspective our model is equivalent to the total variation diminishing tvd scheme in the eulerian description in addition the statistical model provides a new tool to estimate kinematic uncertainties in the hazard analysis of debris flows on gis platforms

source rock distribution and maturation in the zagros orogenic belt provenance of the asmari and bangestan reservoir oil accumulations abstract the zagros orogenic belt of iran is one of the most prolific petroliferous areas accounting for approx 12 of proven global reserves correlation techniques reveal that a majority of the oils variously reservoired in asmari oligo miocene and bangestan group upper cretaceous anticlinal structures share a common provenance oils of the n e khuzestan fields are an exception showing a conspicuously different origin candidate source potential for the crucial central zagros embayment and contiguous areas was assessed on field survey and from well materials collected during the decade from 1968 onwards although varying locally in vertical and lateral distribution attractive sources occur throughout the section included were silurian shales the sargelu middle jurassic garau gadvan lower cretaceous kazhdumi albian gurpi upper cretaceous and pabdeh paleogene fms maturation of these source units was essentially controlled by the foredeep subsidence related to the zagros orogeny being a neogene event hydrocarbon generation and migration are very recent and essentially synorogenic consolidation of this information with the real distribution of candidate sources application of carbon isotope based source oil assignments and biomarker results successfully differentiated the provenance of the generic oil groupings over much of khuzestan the kazhdumi was recognised as the major contributor elsewhere the pabdeh fm yields isotopically distinctive oils in n e khuzestan evaluation of this basin allowed identification of prolific source rocks in low energy euxinic argillaceous lime mudstones similarly it provided an early application of pyrolysis techniques carbon isotopic correlations and subsidence history maturation migration modelling approaches now routinely employed in basin evaluation

numerical analysis of dynamics of debris flow over erodible beds in wenchuan earthquake induced area the basal entrainment of debris flows play a significant role in its amplification and the final volume of deposition could be several to hundred times of its initial volume in this paper the shallow water equations coupled with basal material entrainment applied in debris flows have been given to demonstrate the amplification a new basal entrainment model taking advantage of both coulomb and voellmy frictional laws are proposed providing a unified formula to simulate the stop and go process of debris flows both time and space second order maccormack tvd finite difference method is suggested to solve the coupled equations numerical comparisons with usgs flume experiment and hongchun gully debris flow in wenchuan earthquake induced area are carried out to prove its effectiveness it is established that the momentum exchange term between the flows and the basal materials has a significant influence on the dynamic characteristics and the entrainment effects are essential to model the dynamic process of debris flows in an earthquake induced area c 2014 elsevier b v all rights reserved

integrated seismic source model of the 2015 gorkha nepal earthquake we compared spatiotemporal slip rate and high frequency around 1 hz radiation distributions from teleseismic p wave data to infer the seismic rupture process of the 2015 gorkha nepal earthquake for these estimates we applied a novel waveform inversion formulation that mitigates the effect of green s functions uncertainty and a hybrid backprojection method that mitigates contamination by depth phases our model showed that the dynamic rupture front propagated eastward from the hypocenter at 3 0 km s and triggered a large slip event centered about 50 km to the east it also showed that the large slip event included a rapid rupture acceleration event and an irregular deceleration of rupture propagation before the rupture termination heterogeneity of the stress drop or fracture energy in the eastern part of the rupture area where aftershock activity was high inhibited rupture growth high frequency radiation sources tended to be in the deeper part of the large slip area which suggests that heterogeneity of the stress drop or fracture energy there may have contributed to the damage in and around kathmandu

real time observation of an active debris flow watershed in the wenchuan earthquake area abstract debris flows occur frequently and cause considerable damage in the wenchuan earthquake area however there has been no systematic real time monitoring of such events this study used a monitoring system to consider the spatial variation of meteorological and flow processes in a 39 4 km2 watershed the system comprised three rainfall gauges at different locations and three hydrological monitoring stations located on the mainstream and tributaries with instruments to measure the velocity height and density of debris flows based on the monitoring data the debris flow events were categorized and the general runoff velocity discharge and density were analysed we proposed empirical methods for estimating the velocity and the total volume of debris flows based on other easily obtainable parameters e g maximum flow depth and duration comparison of the results derived using the monitoring data and empirical formulas with those obtained in other small watersheds worldwide revealed the debris flow characteristics in this relatively large watershed rainfall threshold for the debris flows was proposed which is higher than those proposed for the same region for periods shortly after the wenchuan earthquake 2008 2013 and the temporal evolution of the rainfall conditions necessary for debris flows was addressed

mapping of the high frequency source radiation for the loma prieta earthquake california waveform inversion has been successfully applied to map the spatial distribution of earthquake fault slip from strong motion records but its application has been restricted to a relatively lower frequency range of the data 5 hz generation is incoherent between neighboring patches on the fault we formulated an analytical model for calculating the envelope time history of the squared high frequency displacement seismogram this envelope time history is found through the line integration of the squared energy radiation intensity over the isochron using a recursive stochastic inversion scheme we determined both the lower frequency slip distributions from the low pass filtered strong motion displacement data and the higher frequency energy radiation intensity from the envelope of the squared high frequency displacement data on an extended fault for the 1989 loma prieta earthquake respectively our resulting lower frequency slip model shows that there are two main slip patches and little slip directly updip of the hypocenter one major slip zone located 10 km northwest of the hypocenter with predominant dip slip and the other located 12 km southeast of the hypocenter with predominant oblique slip our preliminary results of the high frequency energy radiation intensity inversion indicate three large high frequency sources and few smaller ones located on the outer periphery of the large slip zones this suggests that the high frequency energy sources are located along or near the boundaries of large slip zones which is consistent with the theoretical consideration that high frequencies are primarily generated from the rupture stopping areas or places with large slip variation

the origin of oil in the cretaceous succession from the south pars oil layer of the persian gulf the origin of the oil in barremian hauterivian and albian age source rock samples from two oil wells spo 2 and spo 3 in the south pars oil field has been investigated by analyzing the quantity of total organic carbon toc and thermal maturity of organic matter om the source rocks were found in the interval 1 000 1 044 m for the kazhdumi formation albian and 1 157 1 230 m for the gadvan formation barremian hauterivian elemental analysis was carried out on 36 samples from the source rock candidates gadvan and kazhdumi formations of the cretaceous succession of the south pars oil layer spol this analysis indicated that the om of the barremian hauterivian and albian samples in the spol was composed of kerogen types ii and ii iii respectively the average toc of analyzed samples is less than 1 wt suggesting that the cretaceous source rocks are poor hydrocarbon hc producers thermal maturity and ro values revealed that more than 90 of oil samples are immature the source of the analyzed samples taken from gadvan and kazhdumi formations most likely contained a content high in mixed plant and marine algal om deposited under oxic to suboxic bottom water conditions the pristane nc17 versus phytane nc18 diagram showed type ii iii kerogen of mixture environments for source rock samples from the spol burial history modeling indicates that at the end of the cretaceous time pre permian sediments remained immature in the qatar arch therefore lateral migration of hc from the nearby cretaceous source rock kitchens toward the north and south of the qatar arch is the most probable origin for the significant oils in the spol

palynofacies and geochemical analysis of the triassic yanchang formation ordos basin implications for hydrocarbon generation potential and the paleoenvironment of continental source rocks abstract the petroliferous basins that have formed in china since the mesozoic are characterized by non marine organic matter input a characteristic that is significantly different from that of marine organic sources the triassic yanchang formation in the ordos basin is a suite of typical intra continental lacustrine sediments that comprise the most important source rocks for the triassic oil reservoirs the yanchang formation is divided into ten subsections from top to bottom chan 1 to chan 10 three borehole successions in the southern ordos basin located in the huachi zhidan and yichuan areas cross the chan 4 5 to chan 10 subsections and have been studied using the palynofacies method combined with organic geochemistry data palynofacies analysis indicates that the sediments are rich in amorphous organic matter aom and phytoclasts the aom content in all of the samples positively correlated with the hydrogen index hi in contrast the transparent ligno cellulosic fragments tlf opaque particles op content are negatively correlated with the hi values additionally the gelified particles gp content has no linear correlation with the geochemistry data based on the quantitative composition of the particulate organic matter three palynofacies types are identified reflecting depositional settings in a distal dysoxic anoxic deep basin a shelf to basin transition zone and a proximal suboxic shelf the palynofacies total organic carbon toc and rock eval data together indicate that type i and ii kerogen are abundant in the d48 and w22 wells in the zhidan and yichuan areas respectively these kerogen types are uncommon in the l94 well in the huachi area which suggests low hydrocarbon generation potential in detail the chan 7 and chan 9 subsections of the three wells contain abundant type i and ii kerogen indicating that these layers are likely the two primary source rocks in the southern ordos basin

occurrence conditions of roll waves for three grain fluid models and comparison with results from experiments and field observation for the flow and deposition behaviour of debris flows phenomena like particle sorting levee formation and the development of roll waves are expected to be important processes however these processes are not well understood and hardly implemented in modelling approaches in this study we focus on the development of roll waves and derive advanced criteria separating stable and instable flow regimes for three debris flowmodels these criteria are expressed using critical froude numbers each of these simple flow models reflect different sources of flow resistance laminar viscous stress bingham type dispersive stress due to particle collision bagnold type and a model combining turbulent and dispersive stresses subsequently we compare the predictions from these models with results from laboratory experiments with grain fluid mixtures in a straight flume and with observations from a debris flow monitoring site at the lattenbach creek in austria the experimental flows match with a turbulent flow model including particle collisions for the natural flows the connection between models and observations is not clear due to limited field data the results of our study contribute to an improved determination of critical flow conditions and provide data for model testing

review and update of the applications of organic petrology part 1 geological applications abstract organic petrology developed as coal petrology at the beginning of the 20th century dedicated mainly to the study of coals because of their utilization in industry coal petrology was then considered a branch of coal science later with the development of specialized nomenclature classification of coal components and the standardization and improvement of analytical microscopical methods this discipline expanded in interests and name becoming organic petrology organic petrology carries a broader context being as well a tool applied in the study of dispersed organic matter in sedimentary rocks due to its importance in exploration for fossil fuel resources at present organic petrology is a discipline widely recognized for its role in fundamental and applied research with respect to both coal utilization and in geosciences throughout the 20th century several important monographs have been published on the discipline of organic petrology including stach s textbook of coal petrology 1st edition 1935 2nd 1975 3rd 1982 updated as the more general organic petrology by taylor et al 1998 more recently the text applied coal petrology the role of petrology in coal utilization was published by suarez ruiz and crelling 2008 this review is the first in a two part review series that describes and updates the role of organic petrology in geosciences a second part complementing this one and focused on the applications of organic petrology to other scientific fields will follow

field observations of a debris flow event in the dolomites a debris flow event occurred in june 1997 in the dolomites eastern alps italy the phenomenon was directly observed in the field and recorded by a video camera near its initiation area the debris flow originated shortly after an intense rainstorm 25 mm in 30 min whose runoff mobilised the loose coarse debris that filled the bottom of the channel in its upper part the analysis of the steep headwater basin indicates a very short concentration time 9 14 min that fits the quick hydrological response observed in the field the debris flow mobilisation was not contemporaneous with the arrival of the peak water discharge in the initiation area probably due to the time required for the saturation of the highly conductive channel bed material channel cross section measurements taken along the flow channel indicate debris flow peak velocity and discharge ranging from 3 1 to 9 0 m s and from 23 to 71 m3 s respectively samples collected immediately after deposition were used to determine the water content and bulk density of the material channel scouring fines enrichment and transported volume increase testify erosion and entrainment of material along the flow channel field estimates of the rheological properties based on open channel flow of bingham fluid indicate a yield strength of 5000 400 pa and relatively low viscosity 60 326 pa s probably due to a high percentage of fines approx 30

flow resistance of inertial debris flows abstractthis work deals with the evaluation of the most suitable expression for the motion resistance of a debris flow in particular it focuses on inertial debris flows i e granular fluid mixtures in which the particle inertia dominates both the fluid viscous force and turbulence it provides through an order of magnitude analysis the criterion to be satisfied for a debris flow to be considered inertial and shows that most of real scale debris flows match this description the analytical relation between flow depth depth averaged velocity and tangent of the angle of inclination of the free surface is then used in steady uniform flow conditions to approximate the flow resistance in depth averaged mathematical models of debris flows that resistance formula is tested against experimental results on the longitudinal profile of steady fully saturated waves of water and gravel over both rigid and erodible beds and against field measurements of real events the notable agreement especially in compa

ten years of debris flow monitoring in the moscardo torrent italian alps abstract field data on debris flows are of utmost importance for improving knowledge of these hazardous phenomena and for the development of attenuation measures in alpine basins debris flows generally occur with a frequency high enough to create serious risk to human settlements and transportation routes but too low to justify monitoring activity capable of providing enough data in a sufficiently short time the moscardo torrent a small stream in the eastern italian alps is an exception to this general situation since it displays a high frequency of debris flows commonly at least one event per year in 1989 this torrent was instrumented and the results of the following 10 years 1989 1998 of debris flow monitoring are presented with an analysis of collected data the equipment installed allowed measurement of rainfall flow stage and ground vibrations caused by debris flows other important debris flow variables that is mean front velocity peak discharge and flowing volume were estimated from instrumental records video pictures have proved to be useful for the visual interpretation of debris flow waves and have made it possible to estimate the surface velocity of debris flows recorded data are compared with other experimental data sets collected and documented worldwide advantages and shortcomings of different types of sensors are discussed with relevance both for research monitoring purposes and for possible use in debris flow warning systems

a novel method for measuring the timing of bed erosion during debris flows and floods 1 we describe a novel channel bed erosion sensor and the first results of its usage the sensor is based on a resistance chain built into a column of 5 cm tall cylindrical aluminum elements the timing and change in resistance as elements are removed from the column are logged outside of the channel five sensor columns were placed in the illgraben torrent bed prior to the start of the 2008 flow season before the first debris flow event 0 1 m of sediment was deposited by small flood events during the 16 june 2008 debris flow this layer was eroded and erosion was therefore first measured 44 min after front arrival and took place progressively over the next 12 min the results at the erosion sensors are consistent with measurements over the entire reach using traditional surveying methods and data from the adjacent debris flow monitoring station provide a basis for interpretation the main limitation is that this sensor records only the rate and timing of the maximum bed erosion and cannot be used to determine deposition and subsequent erosion within a given event

characterization of debris flows by rainstorm condition at a torrent on the mount yakedake volcano japan abstract we analyzed rainstorm control on debris flow magnitude and flow characteristics using the 14 sets of rainstorm and debris flow data obtained from 1980 to 2005 at the kamikamihorizawa creek of mount yakedake with the principal component analysis on five parameters of debris flows frontal velocity peak velocity peak flow depth peak discharge and total discharge and with video record of boulder dams in motion and the preceding rainfall intensities we conclude that the 14 debris flows could be categorized into three groups the flows in the first group have large hydraulic magnitude and massive and turbulent boulder dams filled with slurry matrix the flows in the second group have small hydraulic magnitude and boulder dams scarcely filled with slurry matrix and the dam is observed to alternate between stopping and starting the flows in the third group have small hydraulic magnitude and boulder dams filled with slurry matrix analysis of hillslope hydrology and debris flow data asserted that the antecedent rainfall conditions control not only the hydraulic magnitude of debris flows but also the boulder dam features large rainstorms of high intensity and durations as short as 10 minutes induces fast and large storm runoff to the headwaters and the source reaches of debris flow while rainstorms with durations as long as 24 h raises water content in the bottom deposits along the debris flow growth reaches and generates substantial runoff from the tributaries classification of the three groups is done based on water availability to debris flows on the source and growth reaches at the occurrence of debris flow

tectonic controls on residual oil saturation below the present day fluid contact level in reservoirs of the persian gulf abstract the presence of residual oil below the present day free water level fwl and oil water contact owc is common in many oil fields in the middle east particularly those in the persian gulf this residual oil is seen in both clastic and carbonate reservoirs prior to the start of production the characterisation and modelling of these fields is difficult in practice also these residual oils below the fwl and owc could become classified as reserves if ways to produce them could be found however the first step is to better understand their origin therefore the goal of this study was to investigate the role of geological events on the presence of the residual oil zone roz below the fwl and owc it has been suggested that the presence of residual oil below the present day fwl and owc is related to the geotectonic history of the region from the middle miocene reverse faulting and overfolding propagated over the zagros leading to the amplification of folds and the migration of the zagros orogeny towards its foreland basin persian gulf in response to this additional massive loading on the continental margin the forebulge amplitude was increased its location migrated towards the uplifted zagros mountains and consequently the persian gulf became narrower this exerted a north to north east downward tilting of the entire basin including all the structures and reservoirs previously filled by hydrocarbons this basin tilting changed the equilibrium of the structures and their fluid contents and resulted in the hydrocarbons and water attempting to find a new equilibrium under these conditions the early migrated and accumulated oil was flushed out by water imbibition and a roz was left below the present day fwl and owcs the angle of regional basin tilt has been calculated to be 0 836 based on seismic sections

catastrophic debris flows on 13 august 2010 in the qingping area southwestern china the combined effects of a strong earthquake and subsequent rainstorms in the wenchuan area in sw china an abundance of loose co seismic landslide debris was present on the slopes after the wenchuan earthquake which in later years served as source material for rainfall induced debris flows or shallow landslides slopes composed of cambrian sandstones and siltstones intercalated with slates appeared to be most susceptible to co seismic landsliding a total of 20 debris flows are described in this paper all were triggered by heavy rainfall on 13th of august 2010 field reconnaissance and measurements supported by aerial photo interpretation were conducted to identify the locations and morphological characteristics of the debris flow gullies in order to obtain information about surface area and volume of landslides and the debris flows the debris flows in the study area were initiated by two processes a run off erosion on co seismic landslide material and concentrated erosion of landslide debris in steep channels b new landslides that transform into debris flows the volume of debris flow deposits on individual fans varies by many orders of magnitude the smallest deposit has a volume of from 5760 to 3 1 million m3 a comparison of the measured volumes deposited on the fan with the volumes of debris stored in the catchment shows the huge potential for future debris flow activity whilst there is a weakly significant positive correlation between these two volumes no significant statistical correlation could be established between volumes of debris flow deposits and other morphometric parameters of the catchment a catastrophic debris flow catchment the wenjia catchment was selected as an extreme case to show in detail the mechanism of debris flow formation as a result of intensive erosion in loose material which was deposited by a rock avalanche during the 2008 earthquake event analyses of the meteorological conditions that triggered these debris flows show one day antecedent precipitation varying between 67 7 and 137 6 mm with a mean rainfall intensity of about 7 3 to 22 5 mm h a rainfall event with peak intensity of 38 7 mm h triggered the largest debris flow event rainfall data related to five debris flow events in the wenjia torrent was used to establish a primary rainfall intensity duration relationship for the triggering of debris flows which was compared to other rainfall duration thresholds from other parts of the world in the discussion emphasis is laid on the need to unravel the process mechanisms which initiated the debris flows for a better understanding and assessment of meteorological thresholds

initiation conditions for debris flows generated by runoff at chalk cliffs central colorado abstract we have monitored initiation conditions for six debris flows between may 2004 and july 2006 in a 0 3 km 2 drainage basin at chalk cliffs a band of hydrothermally altered quartz monzonite in central colorado debris flows were initiated by water runoff from colluvium and bedrock that entrained sediment from rills and channels with slopes ranging from about 14 to 45 the availability of channel material is essentially unlimited because of thick channel fill and refilling following debris flows by rock fall and dry ravel processes rainfall exceeding i 6 61 d 0 77 where i is rainfall intensity mm h and d is duration h was required for the initiation of debris flows in the drainage basin the approximate minimum runoff discharge from the surface of bedrock required to initiate debris flows in the channels was 0 15 m 3 s colluvium in the basin was unsaturated immediately prior to antecedent and during debris flows antecedent volumetric moisture levels in colluvium at depths of 1 cm and 29 cm ranged from 4 9 and 4 7 respectively during debris flows peak moisture levels in colluvium at depths of 1 cm and 29 cm ranged from 10 20 and 4 12 respectively channel sediment at a depth of 45 cm was unsaturated before and during debris flows antecedent moisture ranged from 20 22 and peak moisture ranged from 24 38 although we have no measurements from shallow rill or channel sediment we infer that it was unsaturated before debris flows and saturated by surface water runoff during debris flows our results allow us to make the following general statements with regard to debris flows generated by runoff in semi arid to arid mountainous regions 1 high antecedent moisture levels in hillslope and channel sediment are not required for the initiation of debris flows by runoff 2 locations of entrainment of sediment by successive runoff events can vary within a basin as a function of variations in the thickness of existing channel fill and the rate of replenishment of channel fill by rock fall and dry ravel processes following debris flows and 3 rainfall and simulated surface water discharge thresholds can be useful in understanding and predicting debris flows generated by runoff and sediment entrainment

comprehensive source rock evaluation of the kazhdumi formation in the iranian zagros foldbelt and adjacent offshore abstract the kazhdumi formation is regarded as one of the most prolific hydrocarbon sources in the zagros foldbelt and adjacent offshore rock eval pyrolysis data were collected from 2300 rock samples of the kazhdumi formation in 64 wells core and cutting including 37 oil and gas fields and five outcrops 200 vitrinite reflectance measurements were carried out to calibrate and map thermal maturity over the study area palynofacies analyses and thermal history modeling were applied on the wells located in the study area based on the total organic carbon toc map the kazhdumi formation toc values range from 0 to 11 in the central part of dezful embayment its average value is about 5 while average toc value of the kazhdumi formation is lower than 0 5 in qatar gawbandi paleo high hydrogen index hi values represented types ii and iii kerogen for central part of the dezful embayment and qatar gawbandi paleo high respectively t max ranges from 370 to 455 c in the study area the maximum and minimum values for this parameter are recorded in the central dezful embayment and central persian gulf anticlines respectively vitrinite reflectance vr r map also confirms the concluded results of t max data reconstructed burial history and thermal modeling of three wells are also in full agreement with the results of other maturity evidence t max and vr r palynofacies analyses revealed that this formation in the central persian gulf south pars field clearly represents the dominance of terrigenous elements which were resulted from a close proximity to a fluvio deltaic source however towards the northwest amorphous organic matter aom dominates in central dezful embayment indicating a distal dysoxic anoxic environmental condition

high frequency monitoring of debris flow propagation along the real torrent southern french prealps abstract the real torrent 2 3 km2 drainage area is a very active debris flow torrent in the french prealps it was equipped with three high frequency monitoring stations in late 2010 to investigate the triggering conditions and propagation of debris flows along the 2 km long torrent channel the monitoring system combines different techniques including rain gauges and measurements of ground vibrations and flow elevations in spring and summer of 2011 five rainfall triggered debris flow events occurred along the torrent most debris fronts deposited in the upstream part of the channel but one large front 1 9 2 0 m high propagated to the catchment outlet with a mean velocity of about 3 m s 1 the volume of this main debris surge was 3900 m3 near the hillslope sources and increased downstream 5500 m3 in the middle part and 8600 m3 near the catchment outlet the debris flow developed a more mature flow pattern as it progressed downstream multiple debris and hyperconcentrated surges were observed upstream while a single debris surge occurred near the catchment outlet the front height remained relatively constant during its propagation whereas its viscosity and velocity tended to decrease downstream as the channel slope decreases the growth of this main debris surge could be explained by the entrainment of in channel sediments and the coalescence of the multiple preliminary surges for the 2011 events rainfall burst duration and intensity were the main factors controlling the occurrence volume and runout distance of debris flows antecedent channel conditions sediment recharge bed wetness and antecedent rainfall are also important factors but further investigations are necessary to better understand the role of these factors regarding the triggering and propagation of debris flows in the real torrent

depositional settings and palynofacies assemblages of the upper triassic fluviodeltaic mungaroo formation northern carnarvon basin western australia

rupture details of the 28 march 2005 sumatra mw 8 6 earthquake imaged with teleseismic p waves 1 we image the rupture of the 28 march 2005 sumatra mw 8 6 earthquake by back projecting teleseismic p waves recorded by the global seismic network and the japanese hi net to their source the back projected energy suggests that the rupture started slowly had a total duration of about 120 s and propagated at 2 9 to 3 3 km s from the hypocenter in two different directions first toward the north for 100 km and then after a 40 s delay toward the southeast for 200 km our images are consistent with a rupture area of 40 000 km2 the locations of the first day of aftershocks and the harvard cmt mw of 8 6 which implies an average slip of 6 m the earthquake is similar in its location size and geometry to a mw 8 5 event in 1861 our estimated average slip is consistent with a partially coupled subduction interface gps forearc velocities and the 59 mm yr convergence rate if the 2005 earthquake released elastic strain that accumulated over many hundreds of years rather than just since the last 1861 event

backprojection of volcanic tremor backprojection has become a powerful tool for imaging the rupture process of global earthquakes we demonstrate the ability of backprojection to illuminate and track volcanic sources as well we apply the method to the seismic network from okmok volcano alaska at the time of an escalation in tremor during the 2008 eruption although we are able to focus the wavefield close to the location of the active cone the network array response lacks sufficient resolution to reveal kilometer scale changes in tremor location by deconvolving the response in successive backprojection images we enhance resolution and find that the tremor source moved toward an intracaldera lake prior to its escalation the increased tremor therefore resulted from magma water interaction in agreement with the overall phreatomagmatic character of the eruption imaging of eruption tremor shows that time reversal methods such as backprojection can provide new insights into the temporal evolution of volcanic sources

sediment entrainment by debris flows in situ measurements from the headwaters of a steep catchment 1 debris flows can dramatically increase their volume and hence their destructive potential by entraining sediment yet quantitative constraints on rates and mechanics of sediment entrainment by debris flows are limited using an in situ sensor network in the headwaters of a natural catchment we measured flow and bed properties during six erosive debris flow events despite similar flow properties and thicknesses of bed sediment entrained across all events time averaged entrainment rates were significantly faster for bed sediment that was saturated prior to flow arrival compared with rates for sediment that was dry bed sediment was entrained from the sediment surface downward in a progressive fashion and occurred during passage of dense granular fronts as well as water rich inter surge flow en massefailure of bed sediment along the sediment bedrock interface was never observed large magnitude high frequency fluctuations in total normal basal stress were dissipated within the upper 5 cm of bed sediment within this near surface layer concomitant fluctuations in coulomb frictional resistance are expected irrespective of the influence of pore fluid pressure or fluctuations in shear stress if the near surface sediment was wet as it was overridden by a flow additional large magnitude high frequency pore pressure fluctuations were measured in the near surface bed sediment these pore pressure fluctuations propagated to depth at subsonic rates and in a diffusive manner the depth to which large excess pore pressures propagated was typically less than 10 cm but scaled as d fi 0 5 in which d is the hydraulic diffusivity and fiis the frequency of a particular pore pressure fluctuation shallow penetration depths of granular normal stress fluctuations and excess pore pressures demonstrate that only near surface bed sediment experiences the full dynamic range of effective stress fluctuations and as a result can be more easily entrained than deeper sediment these data provide robust tests for mechanical models of entrainment and demonstrate that a debris flow over wet bed sediment will be larger than the same flow over dry bed sediment

magnitude frequency relations in debris flow debris flow occurs frequently in mountainous regions in china because of the difficulties involved in predicting and catching live debris flows an assessment of the potential for debris flow is crucial in hazard mitigation magnitude frequency mf relations are of special significance in such assessments in previous studies mf relations have been inferred by analyzing environmental factors and historical records and using empirical relations this paper is concerned with the derivation of mf relations at regional and valley scales using a large database of statistics at the regional scale it is represented by the distribution of the valley area because the area is often taken to indicate the potential magnitude of debris flow statistics from over 5 000 debris flow valleys in various provinces in china show that a power law holds for the distribution i e p a a n where p a is the percentage of valleys with area a and n varies with region and thus describes regional differences at the valley scale a case study focusing on jiangjia gully jjg was conducted and the mf relations derived from it were expressed by the distributions of discharge and runoff i e the total volume of living debris flows observed over the last 40 years the distributions can be expressed as exponential functions where the exponents vary with the events these mf relations provide not only a potential quantitative reference for practical purposes but also hint at the intrinsic properties of the debris flow

organic geochemistry and petrography of kazhdumi albian cenomanian and pabdeh paleogene potential source rocks in southern part of the dezful embayment iran there are several source rock units in the zagros basin but the cretaceous kazhdumi and paleogene pabdeh formations probably have produced the majority of the commercial hydrocarbons in this area among the hydrocarbon provinces of iran the dezful embayment which is located southwest of zagros mountains is one of the most prolific regions in the middle east numerous studies have been made in the northern part of the dezful embayment but relatively few have been done in its southern part the present study focuses on organic matter characterization of two potential source rocks kazhdumi and pabdeh formations in southern part of the dezful embayment cuttings samples 114 were collected from 10 wells and evaluated using rock eval pyrolysis and organic petrography in order to characterize the content and type of organic matter and thermal maturity the results showed that the average total organic carbon toc content of kazhdumi and pabdeh formations are 2 48 and 1 62 wt respectively the highest toc contents for both formations are found in the northern compartment and decreased gradually toward the south pyrolysis data reveal that organic matter has a fair to very good hydrocarbon generation potential and are classified as type ii iii and type iii rock eval t max and vitrinite reflectance show that the majority of samples are in the early mature to mature stage of the oil generation window c 2012 elsevier ltd all rights reserved

neogene sediments and modern depositional environments of the zagros foreland basin system a sedimentological investigation of the neogene deposits of the zagros foreland basin in sw iran reveals a continuous and largely gradational passage from supratidal and sabkha sediments at the base represented by the gachsaran formation to carbonates and marine marls mishan formation with basal guri carbonate member followed by coastal plain and meandering river deposits agha jari formation and finally to braided river gravel sheets bakhtyari formation this vertical succession is interpreted to represent the southward migration of foreland basin depozones from distal foredeep and foredeep to distal wedge top and proximal wedge top respectively as the zagros fold thrust belt migrated progressively southward towards the arabian foreland this vertical succession bears a striking similarity to modern depositional environments and sedimentary deposits observed in the zagros region today where one passes from mainly braided rivers in the zagros mountains to meandering rivers close to the coast to shallow marine clastic sediments along the northern part of the persian gulf and finally to carbonate ramp and sabkha deposits along the southeastern coast of the persian gulf this link between the neogene succession and the modern day depositional environments strongly suggests that the major neogene formations of the zagros foreland basin are strongly diachronous as shown recently by others and have active modern day equivalents

tracking high frequency seismic source evolution 2004 mw 8 1 macquarie event the 2004 mw 8 1 event on 23 december 2004 near the macquarie ridge is a very large intraplate event that has been overshadowed by the mw 9 3 sumatra andaman event only 3 days later we are able to track the progress of source evolution by estimating the progression of the points of energy emission exploiting the good azimuthal distribution of available stations the results indicate that this event ruptured on two nearby fault systems reactivating fossil fracture zones with the second subevent to the west triggered by the first the total duration of high frequency radiation is quite short about 60 s for such a large event much of the high frequency radiation occurs on a fault subparallel to that inferred from long period studies this composite fault behavior with displaced triggered failure appears to be a characteristic of large intraplate events beneath the oceans

evolution of a natural debris flow in situ measurements of flow dynamics video imagery and terrestrial laser scanning many theoretical and laboratory studies have been undertaken to understand debris flow processes and their associated hazards however complete and quantitative data sets from natural debris flows needed for confirmation of these results are limited we used a novel combination of in situ measurements of debris flow dynamics video imagery and pre and postflow 2 cm resolution digital terrain models to study a natural debris flow event our field data constrain the initial and final reach morphology and key flow dynamics the observed event consisted of multiple surges each with clear variation of flow properties along the length of the surge steep highly resistant surge fronts of coarse grained material without measurable pore fluid pressure were pushed along by relatively fine grained and water rich tails that had a wide range of pore fluid pressures some two times greater than hydrostatic surges with larger nonequilibrium pore fluid pressures had longer travel distances a wide range of travel distances from different surges of similar size indicates that dynamic flow properties are of equal or greater importance than channel properties in determining where a particular surge will stop progressive vertical accretion of multiple surges generated the total thickness of mapped debris flow deposits nevertheless deposits had massive vertically unstratified sedimentological textures

palynology and petroleum potential of the kazhdumi formation cretaceous albian cenomanian in the south pars field northern persian gulf abstract the kazhdumi formation of the bangestan group is a well known source rock that has produced abundant oil in most petroleum fields in the zagros basin which stretches from northwest to southwest iran over hundreds of kilometres the formation reaches a thickness of 230 m at the type section in northwest zagros but thins out to 40 50 m in wells studied from the south pars giant petroleum field where it comprises mainly grey shales with occasional intercalations of marls and sandstones south pars best known as the iranian part of the world s largest non associated gas field contains small quantities of oil above and below the kazhdumi formation palynology has been used to assess the age and palaeoenvironment of the kazhdumi formation and to evaluate its petroleum potential a total of 68 ditch cutting samples recovered from five wells of which four are oil prone have been analyzed an age between late albian and cenomanian is established for the formation based on dinoflagellate cyst biostratigraphy and four palynofacies types have been recognized using the relative proportions of terrestrial elements marine palynomorphs and amorphous organic matter aom the ratio of terrestrial to marine elements is high in most samples indicating a nearshore sedimentary environment twenty two samples from the four oil prone wells were also selected for geochemical analysis using rock eval pyrolysis results show that the kazhdumi formation at south pars in contrast to the zagros basin is gas prone predominantly type iii kerogen thermally immature and poor in terms of hydrocarbon generation it could not have produced the oil in those oil prone wells studied

quantitative analysis of debris torrent hazards for design of remedial measures debris torrents which are rapid flows of soil and organic debris down steep mountain channels are a major natural hazard in many parts of british columbia a series of recent occurrences along the

scale amplification of natural debris flows caused by cascading landslide dam failures debris flows are typically caused by natural terrain landslides triggered by intense rainfalls if an incoming mountain torrent collapses a series of landslide dams large debris flows can form in a very short period moreover the torrent can amplify the scale of the debris flow in the flow direction the catastrophic debris flows that occurred in zhouqu china on 8 august 2010 were caused by intense rainfall and the upstream cascading failure of landslide dams along the gullies in the wake of the incident a field study was conducted to better understand the process of cascading landslide dam failures and the formation of debris flows this paper looks at the geomorphic properties of the debris flow gullies estimates the peak flow discharges at different locations using three different methods and analyzes the key modes i e different landslide dam types and their combinations of cascading landslide dam failures and their effect on the scale amplification of debris flows the results show that five key modes in luojiayu gully and two modes in sanyanyu gully accounted for the scale amplification of downstream debris flows in the zhouqu event this study illustrates how the hazardous process of natural debris flows can begin several kilometers upstream as a complex cascade of geomorphic events failure of landslide dams and erosion of the sloping bed can scale to become catastrophic discharges neglecting recognition of these hazardous geomorphic and hydrodynamic processes may result in a high cost

palynological palynofacies paleoenvironmental and organic geochemical studies on the upper cretaceous succession of the gptsw 7 well north western desert egypt abstract the present study of the abu roash and bahariya formations in well gptsw 7 refines our understanding of the subsurface cretaceous of the north western desert of egypt our investigations are based on the palynological analyses of 71 cuttings samples of which 24 have also been analyzed for geochemistry in addition to 3 sidewall cores analyzed for vitrinite reflectance r o four palynological zones and three subzones in addition to a poorly fossiliferous interval ranging in age from coniacian santonian to early cenomanian are proposed these include a poorly fossiliferous interval coniacian santonian dinogymnium vozzhennikovae interval zone late to middle turonian ephedripites ambiguus ephedripites multicostatus foveotricolpites giganteus foveotricolpites gigantoreticultus assemblage zone early turonian classopollis brasiliensis interval zone late to middle cenomanian and afropollis jardinus interval zone early cenomanian the succeeding subzones are afropollis kahramanensis interval subzone elaterosporites klaszii interval subzone and cretacaeiporites densimurus interval subzone all of early cenomanian age total organic carbon toc and rock eval pyrolysis and palynofacies analyses indicate that the bahariya formation and the abu roash g member are primarily of kerogen iii type and hence gas prone suggesting a strong influence of hydrogen enriched organic matter the abu roash a c e members may also be gas prone type iii kerogen and appear to contain highly oxidized terrestrial organic matter in contrast the abu roash f member has very high toc and hi values and contains a very high proportion of amorphous organic matter aom indicating a highly oil prone facies while this finding is not unexpected for anoxic black shale it contrasts with earlier studies that suggest a gas prone nature r o measurements show that the bahariya formation represents an immature early genesis dry gas phase this is also true for all investigated samples from the abu roash and bahariya formations based on their low thermal alteration index tai quantitative and qualitative analyses of both the palynoflora and palynofacies show that the abu roash a and c members b is missing both of coniacian santonian age represent oxic proximal and distal shelf environment the abu roash d and e members dated as turonian represent oxic proximal shelf whereas the cenomanian abu roash f member was deposited in a distal suboxic anoxic basin the cenomanian abu roash g member and the bahariya formation were deposited in a shallow marine and shallow marine to fluvio deltaic setting respectively the senonian palmae province is recognized in the palynoflora by the presence of proteacidites auriculiidites reticulatus ariadnaesporites gabonisporis vigourouxii on the other hand the albian cenomanian elaterates province is characterized by the presence of steevesipollenites gnetaceaepollenites elaterocolpites elaterosporites elateroplicites senegalosporites sofrepites afropollis and cretacaeiporites

tracking the rupture of the mw 9 3 sumatra earthquake over 1 150 km at teleseismic distance on 26 december 2004 a moment magnitude mw 9 3 earthquake occurred along northern sumatra the nicobar and andaman islands resulting in a devastating tsunami in the indian ocean region the rapid and accurate estimation of the rupture length and direction of such tsunami generating earthquakes is crucial for constraining both tsunami wave height models as well as the seismic moment of the events compressional seismic waves generated at the hypocentre of the sumatra earthquake arrived after about 12 min at the broadband seismic stations of the german regional seismic network grsn located approximately 9 000 km from the event here we present a modification of a standard array seismological approach and show that it is possible to track the propagating rupture front of the sumatra earthquake over a total rupture length of 1 150 km we estimate the average rupture speed to be 2 3 2 7 km s 1 and the total duration of rupture to be at least 430 s and probably between 480 and 500 s

rupture imaging of the mw 7 9 12 may 2008 wenchuan earthquake from back projection of teleseismic p waves 1 the mw 7 9 wenchuan earthquake of 12 may 2008 was the most destructive chinese earthquake since the 1976 tangshan event tens of thousands of people were killed hundreds of thousands were injured and millions were left homeless here we infer the detailed rupture process of the wenchuan earthquake by back projecting teleseismic p energy from several arrays of seismometers this technique has only recently become feasible and is potentially faster than traditional finite fault inversion of teleseismic body waves therefore it may reduce the notification time to emergency response agencies using the iris dmc we collected 255 vertical component broadband p waves at 30 95 from the epicenter we found that at periods of 5 s and greater nearly all of these p waves were coherent enough to be used in a global array we applied a simple down sampling heuristic to define a global subarray of 70 stations that reduced the asymmetry and sidelobes of the array response function arf we also considered three regional subarrays of seismometers in alaska australia and europe that had apertures less than 30 and p waves that were coherent to periods as short as 1 s individual arfs for these subarrays were skewed toward the subarrays however the linear sum of the regional subarray beams at 1 s produced a symmetric arf similar to that of the groomed global subarray at 5 s for both configurations we obtained the same rupture direction rupture length and rupture time we found that the wenchuan earthquake had three distinct pulses of high beam power at 0 23 and 57 s after the origin time with the pulse at 23 s being highest and that it ruptured unilaterally to the northeast for about 300 km and 110 s with an average speed of 2 8 km s it is possible that similar results can be determined for future large dip slip earthquakes within 20 30 min of the origin time using relatively sparse global networks of seismometers such as those the usgs uses to locate earthquakes in near real time

the cretaceous source rocks in the zagros foothills of iran an example of a large size intracratonic basin the zagros orogenic belt of iran is one of the world most prolific petroleum producing area however most of the oil production is originated from a relatively small area the 60 000 km sup 2 wide dezful embayment which contains approximately 12 of the proven oil global reserves the distribution of the oil and gas fields results from the area extent of six identified source rock layers their thermal history and reservoir cap rock and trap availability in this paper the emphasis is three of the layers of cretaceous sources rocks the garau facies was deposited during the neocomian to albian interval over lurestan northeast khuzestan and extends over the extreme northeast part of fars the kazhdumi source rock which deposited over the dezful embayment and eventually the senonian gurpi formation which has marginal source rock characteristics in limited areas of khuzestan and northern fars the deposition environment of these source rock layers corresponds to semipermanent depressions included in an overall shallow water intracratonic basin communicating with the south tethys ocean these depressions became anoxic when climatic oceanographical and geological conditions were adequate i e humid climate high stand water influxes of fine grained clastics and the existence of sills separating the depressionmore from the open sea distribution maps of these source rock layers resulting from extensive field work and well control are also given the maturation history of source rocks is reconstructed from a set of isopachs it was found that the main contributor to the oil reserves is the kazhdumi source rock which is associated with excellent calcareous reservoirs less

inversion of strong ground motion and teleseismic waveform data for the fault rupture history of the 1979 imperial valley california earthquake a least squares point by point inversion of strong ground motion and teleseismic body waves is used to infer the fault rupture history of the 1979 imperial valley california earthquake the imperial fault is represented by a plane embedded in a half space where the elastic properties vary with depth the inversion yields both the spatial and temporal variations in dislocation on the fault plane for both right lateral strike slip and normal dip slip components of motion inversions are run for different fault dips and for both constant and variable rupture velocity models effects of different data sets are also investigated inversions are compared which use the strong ground motions alone the teleseismic body waves alone and simultaneously the strong ground motion and teleseismic records the inversions are stabilized by adding both smoothing and positivity constraints the moment is estimated to be 5 0 10 25 dyne cm and the fault dip 90 5 dislocation in the hypocentral region south of the united states mexican border is relatively small and almost dies out near the border dislocation then increases sharply north of the border to a maximum of about 2 m under interstate 8 dipslip motion is minor compared to strike slip motion and is concentrated in the sediments the best fitting constant rupture velocity is 80 per cent of the local shear wave velocity however there is a suggestion that the rupture front accelerated from the hypocenter northward the 1979 imperial valley earthquake can be characterized as a magnitude 5 earthquake at the hypocenter which then grew into or triggered a magnitude 6 earthquake north of the border

geodetic data inversion using a bayesian information criterion for spatial distribution of fault slip summary we developed a new inversion method to reconstruct static images of seismic sources from geodetic data using akaike s bayesian information criterion abic coseismic surface displacements are generally related with a slip distribution on a fault surface by linear integral equations parametric expansion of the fault slip distribution by a finite number of known basis functions yields a set of observation equations expressed in a simple vector form incorporating prior constraints on the smoothness of slip distribution with the observation equations we construct a bayesian model with unknown hyperparameters the optimal values of the hyperparameters which control the structure of the bayesian model are objectively determined from observed data by using abic once the values of hyperparameters are determined we can use the maximum likelihood method to find the optimal distribution of fault slip we examined the validity of this method through a numerical experiment using theoretical data with random noise we analysed geodetic data associated with the 1946 nankaido earthquake ms 8 2 by using this method the result shows that the fault slip distribution of this earthquake has two main peaks of 4 and 6 m located off kii peninsula and muroto promontory these two high slip areas are clearly separated by a low slip zone extending along kii strait such a slip distribution corresponds with the fact that the rupture process of this earthquake in the western part is notably different from that in the eastern part

impact of uncertainty in rainfall estimation on the identification of rainfall thresholds for debris flow occurrence abstract estimation of rainfall intensity duration thresholds used for the identification of debris flow landslide triggering rainfall events has been traditionally based on raingauge observations the main drawback of using information from gauges is that the measurement stations are usually located far away from the debris flow initiation areas in complex terrain where debris flows take place the spatial variability of rainfall can be very high and this translates in large uncertainty of raingauge based estimates of debris flow triggering rainfall this work focuses on the assessment of the impact of rainfall estimation uncertainty on identification and use of rainfall thresholds for debris flow occurrence the upper adige river basin northern italy is the area of study a detailed database of more than 400 identified debris flow initiation points during the period 2000 2010 and a raingauge network of 100 stations comprise the database used for this work the methodology examines the intensity duration thresholds derived from a set of raingauges that are assumed to be located at debris flow initiation points dfrs and an equivalent set of raingauges assumed to have the role of the closest to debris flow available measurement mrs a set of reference rainfall thresholds is used to identify the rainfall events at dfrs that triggered debris flows i e exceed the threshold for these same events the corresponding rainfall thresholds are derived from mr observations comparison between the rainfall thresholds derived from dfrs and mrs revealed that uncertainty in rainfall estimation has a major impact on estimated intensity duration thresholds specifically the results showed that thresholds estimated from mr observations are consistently underestimated evaluation of the estimated thresholds for warning procedures showed that while detection is high the main issue is the high false alarm ratio which limits the overall accuracy of the procedure overall performance on debris flow prediction was shown to be good for low rainfall thresholds and poor for high rainfall thresholds examined lastly it was found that filtering out rainfall events with duration

himalayan seismic hazard the devastating earthquake in bhuj on 26 january 2001 highlighted the high earthquake risk in the indian region of gujarat in their perspective bilham et al warn that major earthquakes may be expected in another part of india the himalayan arc an analysis of historic earthquakes suggests that several major earthquakes are overdue in this region but that recent low activity has focused attention away from the himalayan arc projections from earlier earthquakes suggest that just one of the possibly overdue himalayan earthquakes may lead to 200 000 predictable fatalities

how a mud dominated ramp changed to a carbonate clastic oil reservoir sea level fluctuations in cretaceous of the central persian gulf abstract mud dominated facies distribution of barremian turonian succession in the northeastern arabian plate in the central persian gulf represents a shallow ramp platform on the basis of petrographical studies core analysis data and gamma ray logs this succession has been studied for facies analysis defining depositional environment sequence stratigraphy and reservoir properties a total of 6 microfacies and 3 petrofacies types are recognized in this succession lagoonal environment was dominated during the deposition of dariyan kazhdumi and sarvak formations the lagoon rapidly changed to a sand shoal by falling sea level and increasing energy level of the depositional environment sequence stratigraphy of barremian turonian succession shows that mud dominated facies have been deposited in tsts and grain dominated facies in hsts of the sequences although grain dominated facies like packstone to grainstone and algal floatstone were spread during the hsts of sequences the changes in the texture and size of the grains had a negligible effect on reservoir quality during this period barremian turonian two major sea level falls caused considerable environmental changes such as platform emergence incised valley fills and clastic sediments influx into the carbonate platform meteoric diagenesis during the falling sea level had a major effect on the reservoir properties of the reservoirs under the sequence boundaries grains matrix and micrite dissolution and subsequent selective blocky and equant calcite cementation strongly modified the primary reservoir properties local dolomitization also enhance the porosity and permeability of the samples while large pores have been filled by cements microporosities remained unfilled until the late stages of diagenesis and burial