kinematic model of active deformation in central asia the velocity field of present day deformation in central asia is modelled using a set of four rotating blocks siberia tarim tibet india on a spherical earth a best fit is inverted on the basis of estimated shortening rates across the main thrust zones himalayas tien shan and measured slip rates along the principal strike slip faults altyn tagh and karakorum separating those blocks the fit to the data implies that nearly all the present convergence between india and asia can be accounted for by slip partitioning on these four zones with as much as 50 absorbed by northeastwards extrusion of tibet this suggests that localised deformation governs the present mechanical behaviour of the central asian lithosphere

neogene quaternary slow coastal uplift of western europe through the perspective of sequences of strandlines from the cotentin peninsula normandy france abstract the cotentin peninsula normandy france displays sequences of marine terraces and rasas the latter being wide late cenozoic coastal erosion surfaces that are typical of western european coasts in portugal spain france and southern england remote sensing imagery and field mapping enabled reappraisal of the cotentin coastal sequences from bottom to top the n cotentin sequence includes four previously recognized pleistocene marine terraces t1 to t4 at elevations

reservoir fluid substitution effects on seismic profile interpretation a physical modeling experiment p wave seismic surveys are performed on realistic physical models of a reservoir formed of interbedded sand and shale layers and filled with gas water and oil they show characteristic behaviour which can be used to distinguish between fluids with significant implications for the interpretation of time lapse experiments discontinuous reflections originate in gas filled reservoirs with widely varying amplitude compared to oil or water filled reservoirs anomalous changes in seismic amplitude difference attributes for reflections within the reservoir are seen for gas oil substitution oil water substitution results in only weak variations of reservoir elastic properties thus amplitude difference attributes may be unsuitable for monitoring changes in oil water saturation however direct differences between the time traces are strong on time lapse sections strong amplitude difference anomalies do not necessarily correspond to the region where the fluid variations occur this is significant for monitoring oil field development by water injection

estimation of effective porosity using geostatistics and multiattribute transforms a case study the middle eocene kalol formation in the north cambay basin of india is producing hydrocarbons in commercial quantity from a series of thin clastic reservoirs these reservoirs are sandwiched between coal and shale layers and are discrete in nature the kalol formation has been divided into eleven units k i to k xi from top to bottom multipay sands of the k ix unit 2 8 m thick are the main hydrocarbon producers in the study area apart from their discrete nature these sands exhibit lithological variation which affects the porosity distribution low porosity zones are found devoid of hydrocarbons in the available 3d seismic data these sands are not resolved and generate a composite detectable seismic response making reservoir characterization through seismic attributes impossible after proper well to seismic tie the major stratigraphic markers were tracked in the 3d seismic data volume for structural mapping and carrying out attribute analysis the 3d seismic volume was inverted to obtain an aco

inflation deflation cycles revealed by tilt and seismic records at stromboli volcano 1 strombolian activity is driven by gas dynamic where large quantities of volatiles are first exsolved and then suddenly released ejecting fragmented lava at 100 300 m height with exit velocities of 20 70 m s this conduit process is detected as vlp seismicity only in the final stage 10 s before the explosion when the rising gas slug interacts with the shallower part last 200 300 m of the feeding conduits we present new ground deformation recorded with high resolution tiltmeters 1 nrad sampled at 1 hz and detected by broad band seismometers that extends the perception of this explosive process tiltmeters and seismometers reveal that the explosive process is accompanied by a persistent deformation of the ground detected as small 100 nrad inflation deflation cycles 250 s long and associated with the constant process of gas recharge and discharge of the magma conduit

3d seismic attributes for a tight gas sand reservoir characterization of the eastern sulige gas field ordos basin china abstractthe lower permian xiashihezi formation of the ordos basin is the largest producer of tight gas sand in china the controls on tight gas production are many and include a variety of geologic hydrodynamic and engineering factors from one well to another throughout the basin in this study we considered data from a 408 km2 3d seismic volume and logs from 17 wells to investigate the geologic controls on gas production in the p1h8 member of the xiashihezi formation eastern sulige gas field ordos basin our objective was to determine the potential of applying multiple seismic attributes to identify the higher productivity areas of a tight gas sand reservoir to achieve this we used amplitude complex traces spectral decomposition and seismic attenuation attributes derived from the 3d seismic volume to detect gas bearing sand areas the results of seismic attribute analysis revealed that no single attribute is correlated to higher productivity areas the qualitative correlations between attribut

seismic architecture of a lower cretaceous platform to slope system santa agueda and poza rica fields mexico two three dimensional seismic data sets over the albian western golden lane margin and time equivalent basinal deposits of poza rica field allowed us to investigate the linked architecture of a steep sided carbonate platform el abra formation and a thick accumulation of redeposited carbonate sediment at the toe of the slope and in the basinal area tamabra formation regional seismic cross sections show that the most aggrading albian platform has an eroded platform top a scalloped margin and a channelized slope that are equivalent to a 20 km 12 4 mi wide westward thinning thick toe of slope apron made of chaotic contorted mounded moderate to high amplitude reflections detailed reflection geometries in the albian toe of slope and basinal deposits consist of chaotic to short discontinuous low amplitude reflection at the toe of the slope of the golden lane platform laterally changing to a discontinuous mounded shingling reflection which ultimately turns into high amplitude parallel reflections we interpret this lateral change to reflect the seismic signature of the change from the block and debris flow dominated toe of slope area to debris flow and concentrated density flow deposits in the basin that ultimately grade laterally into pelagic deposits on a flattened seismic slice mounded reflections correspond to lobate to fan shaped seismic events several kilometers wide that are interpreted as a carbonate basin floor fan comparison between core and seismic data shows a dominance of debris flows in the lower two albian sequences albian 1 and albian 2 that grade vertically into more lobate concentrated density flows and turbidites in the upper two albian sequences albian 3 and albian 4 seismic data used in this study combined with core observations do not support the interpretation of the albian tamabra formation being of shallow water origin seismic features identified as basin floor fan channel and debris flow deposits have a shape and size that are similar to those of other redeposited basinal carbonate deposits elsewhere the seismic architecture shows that the poza rica field is a typical example of thick accumulation of grainy porous carbonate deposits in a basinal setting this example shows the potential of a large hydrocarbon accumulation in a tectonically modified stratigraphic trap around shallow water carbonate platforms

analysis of scarp profiles evaluation of errors in morphologic dating morphologic analysis of scarp degradation can be used quantitatively to determine relative ages of different scarps formed in cohesionless materials under the same climatic conditions scarps of tectonic origin as well as wavecut or rivercut terraces can be treated as topographic impulses that are attenuated by surface erosional processes this morphological evolution can be modelled as the convolution of the initial shape with erosion or degradation function whose width increases with time such modeling applies well to scarps less than 10m high formed in unconsolidated fanglomerates to a good approximation the degradation function is gaussian with a variance measuring the degree of rounding of the initial shape this geometric parameter can be called the degradation coefficient a synthetic experiment shows that the degradation coefficient can be obtained by least squares fitting of profiles levelled perpendicular to the scarp gravitational collapse of the free face is accounted for by assuming initial scarp slopes at the angle of repose of the cohesionless materials 30 35 uncertainties in the measured profiles result in an uncertainty in degradation coefficient that can be evaluated graphically because the degradation coefficient is sensitive to the regional slope and to three dimensional processes gullying loess accumulation stream incision etc a reliable and accurate determination of degradation coefficient requires several long profiles across the same scarp the linear diffusion model of scarp degradation is a gaussian model in which the degradation coefficient is proportional to numerical age in that case absolute dating requires only determination of the propotionality constant called the mass diffusivity constant for holocene scarps a few meters high in loose alluvium under arid climatic conditions mass diffusivity constants generally range between 1 and 6 m 2 kyr morphologic analysis is a reliable method to compare ages of different scarps in a given area and it can provide approximate absolute ages of holocene scarplike landforms

scaling relationships of channel networks at large scales examples from two large magnitude watersheds in brittany france abstract we present a statistical analysis on two watersheds in french brittany whose drainage areas are about 10 000 and 2000 km 2 the channel system was analysed from the digitised blue lines of the 1 100 000 map and from a 250 m dem link lengths follow an exponential distribution consistent with the markovian model of channel branching proposed by smart 1968 the departure from the exponential distribution for small lengths that has been extensively discussed before results from a statistical effect due to the finite number of channels and junctions the strahler topology applied on channels defines a self similar organisation whose similarity dimension is about 1 7 that is clearly smaller than the value of 2 expected for a random organisation the similarity dimension is consistent with an independent measurement of the horton ratios of stream numbers and lengths the variables defined by an upstream integral drainage area mainstream length upstream length follow power law distributions limited at large scales by a finite size effect due to the finite area of the watersheds a special emphasis is given to the exponent of the drainage area a a that has been previously discussed in the context of different aggregation models relevant to channel network growth we show that a a is consistent with 4 3 a value that was obtained and analytically demonstrated from directed random walk aggregating models inspired by the model of scheidegger 1967 the drainage density and mainstream length present no simple scaling with area except at large areas where they tend to trivial values constant density and square root of drainage area respectively these asymptotic limits necessarily imply that the space dimension of channel networks is 2 equal to the embedding space the limits are reached for drainage areas larger than 100 km 2 for smaller areas the asymptotic limit represents either a lower bound drainage density or an upper bound mainstream length of the distributions because the fluctuations of the drainage density slowly converge to a finite limit the system could be adequately described as a fat fractal where the average drainage density is the sum of a constant plus a fluctuation decreasing as a power law with integrating area a fat fractal hypothesis could explain why the similarity dimension is not equal to the fractal capacity dimension as it is for thin fractals the physical consequences are not yet really understood but we draw an analogy with a directed aggregating system where the growth process involves both stochastic and deterministic growth these models are known to be fat fractals and the deterministic growth which constitutes a fundamental ingredient of these models could be attributed in river systems to the role of terrestrial gravity

source mechanisms of explosions at stromboli volcano italy determined from moment tensor inversions of very long period data 1 seismic data recorded in the 2 30 s band at stromboli volcano italy are analyzed to quantify the source mechanisms of strombolian explosions during september 1997 to determine the source centroid location and source mechanism we minimize the residual error between data and synthetics calculated by the finite difference method for a point source embedded in a homogeneous elastic medium that takes topography into account two source centroids are identified each representative of the distinct event types associated with explosive eruptions from two different vents the observed waveforms are well reproduced by our inversion and the two source centroids that best fit the data are offset 220 and 260 m beneath and 160 m northwest of the active vents the source mechanisms include both moment tensor and single force components the principal axes of the moment tensor have amplitude ratios 1 1 2 which can be interpreted as representative of a crack if one assumes the rock matrix at the source to have a poisson ratio n 1 3 a value appropriate for hot rock both imaged cracks dip 60 to the northwest and strike northeast southwest along a direction parallel to the elongation of the volcanic edifice and a prominent zone of structural weakness as expressed by lineaments dikes and brittle structures for our data set the volume changes estimated from the moments are 200 m 3 for the largest explosion from each vent together with the volumetric source is a dominantly vertical force with a magnitude of 10 8 n consistent with the inferred movement of the magma column perched above the source centroid in response to the piston like rise of a slug of gas in the conduit index terms 7215 seismology earthquake parameters 7280 seismology volcano seismology 8419 8414 volcanology eruption mechanisms keywords very long period seismicity moment tensor inversions eruption mehanics

seismic expression of pleistocene paleoceanographic changes in the california borderland from digitally acquired 3 5 khz subbottom profiles and ocean drilling program leg 167 drilling 1 we correlate processed 3 5 khz seismic profiles with physical properties of cores collected during odp leg 167 from the tanner east cortes and san nicolas basins through much of the pleistocene succession results indicate that seismic horizons in the unconsolidated pleistocene sediments top 50 m are mainly controlled by density contrasts removing of the compaction trend from the density reveals a very interesting relationship between density and composition the density closely and inversely correlates with organic carbon indicating that large scale variations in organic carbon are responsible for seismic reflections through their influence on density this is a significant discovery since there apparently is no other paleoceanographic setting that we know of where such a close linkage between acoustic properties and organic carbon has been established the variations in organic carbon are mainly marine in origin and derive from variations in primary productivity associated with upwelling and the preservation regime related to oxygenation of water pleistocene reflections on 3 5 khz profiles in the borderland province thus record regional cyclical fluctuations in the paleoclimatic signals the close resemblance in the density profiles at the three different basins indicates that the sedimentary regime was similar in those basins through the pleistocene these common density patterns produce regional seismic horizons that correlate well among the basins it is likely these correlated and dated horizons could be extrapolated to other borderland basins e g san clemente where they can potentially be used as time markers for neotectonic studies in the region

applications of 3d seismic attribute analysis in hydrocarbon prospect identification and evaluation verification and validation based on fluvial palaeochannel cross sectional geometry and sinuosity ness county kansas usa abstract due to their high resolution and established success rates the analysis of geometrical and stratigraphic 3d seismic reflection data attributes have become one of the most important tools in many hydrocarbon exploration and development programs in areas with high drilling risk as a result of the lack of spatial continuity and lithological variation of potential prospects analysis of relevant seismic attributes is essential to successful placement of wells this study of the york field ness county kansas presents a corroborative finding based on the analysis of a set of 3d seismic attributes revealing a meandering fluvial channel system incised on the mississippian stratigraphic unconformity north east of a previously interpreted weirman field palaeoshoreline and submarine channels the york field prospect identification and appraisal program targeted the cherokee sands where reservoir properties are favorable and where it was thought that thick cherokee sands correlate with structural mississippian highs we produce evidence that cherokee sand prone fluvial facies is mappable based on synergistic analysis of seismic arrival time amplitude spectral decomposition acoustic impedance and waveform attributes seismic amplitude highs and relative acoustic impedance lows showed moderate conformance with mississippian horizon time lows controls exerted by channel post confluence water and sediments supply provide corroborating hydraulic geometry aspects for the interpreted fluvial system time structural maps in addition to time and horizon slices of several 3d seismic attributes including amplitude spectral decomposition components and relative acoustic impedance all seem to indicate that five previously drilled dry wells within the study area were outside the boundary of a meandering cherokee fluvial system of potential reservoir quality additionally comparisons of the results of this research to previous studies conducted in the south west of ness county have provided an opportunity to support and contribute to interpreted paleodepositional setting established by raef et al 2015 where a palaeoshorline was interpreted the results of this study support a broadly ne sw trending meandering channel system with se flow direction

fault imaging in hydrothermal dolomite reservoirs a case study most hydrocarbon fields found within the ordovician trenton and black river groups of the eastern united states and eastern canada are associated with basement related faults these faults are best imaged by 3d seismic technology because of environmental conditions seismic data often are contaminated by noise that masks fault terminations and reduces signal to noise ratio as a result seismic horizons are discontinuous calculated coherence values are affected adversely and horizon interpretation and fault identification are difficult if not impossible poststack processing is required to attenuate this noise before an optimal interpreta tion can be done we conducted a three step poststack processing flow to attenuate noise and highlight fault terminations noise reducing algorithms consist of frequency space f x deconvolution zero phase filtering and p filtering the structural grain of major faults identified with these techniques agrees with the regional strike of major faults previously de

dinoflagellate cysts and the paleoenvironment of late pliocene early pleistocene deposits of brittany northwest france abstract the marine pliocene facies of the redon clay is widely distributed in the western part of brittany the decrease in the abundance of tertiary pollen towards the top of the deposits coupled with the increase of pollen of boreal forest taxa and the development of ericaceae and poaceae indicates a late pliocene age the occurrence of the transgression maximum is recorded in calcareous beds which contain the highest concentration of microforaminiferal linings and dinoflagellate cysts hystrichokolpoma rigaudae and melitasphaeridium choanophorum along with achomosphaera andalousiensis and operculodinium israelianum make up these aseemblages the presence of dinoflagellate cyst assemblages with estuarine and neritic affinities but with an occasional oceanic form indicates sedimentation in coastal waters with a neritic influence the paleotopography exerts a control on the altitudinal distribution of the redon clays in the western part of brittany to the west of the rennes basin the pliocene pleistocene dinoflagelate cyst assemblages of southern england and northwestern france show a remarkable degree of homogeneity in their composition chiefly expressed in the apparent contradictory association of a andalousensis and o israelianum that suggest sedimentation in an unusual type of environment which arose in the context of climatic change and sea level variations at that time

ghost tilt signal during transient ground surface deformation events insights from the september 3 2010 mw7 1 darfield earthquake new zealand 1 this work assesses whether tiltmeters can reliably measure ground tilt in the 2 20 s band similar to that of very long period volcanic earthquakes seismic waves recorded with co located high rate gps borehole seismometer and bubble tiltmeter during the 2010 mw7 1 darfield earthquake in new zealand are used to determine the response of the tiltmeter the joint analysis of this dataset shows that at least for periods within the aforementioned band the observed tilt signal was in fact not related to ground tilt but instead to translational ground acceleration caused by passing s and surface waves if no independent control on translational motion is provided for recorded very long period volcanic earthquakes within the 2 20 s band the signal recorded on bubble tiltmeters may therefore be misinterpreted the use of co located high rate gps data provides such control and is essential to discriminate translational motion from ground tilt on the recorded seismic and tiltmeter signals

the structural evolution of active fault and fold systems in central otago new zealand evidence revealed by drainage patterns abstract central otago in new zealand is an area of active continental shortening in which a peneplain surface cut into schist has been deformed by folds which are developed above buried reverse faults we use the drainage patterns in this region to demonstrate various processes in fold and fault growth and interaction that would be difficult to identify by other means in particular we show 1 how simple asymmetric folds can develop into box folds 2 how apparently continuous ridges were formed by the coalescing of quite separate propagating fold and fault segments 3 evidence for the relative ages or relative uplift rates of adjacent structures and 4 evidence for the propagation direction of folds or faults as they grow the few quantitative estimates we obtain for fault propagation rates suggest an increase in length of 10 50 m per earthquake on faults about 20 km long these estimates are very uncertain but are similar in magnitude to an estimate made in nevada for a normal fault of similar size and are also similar to predicted estimates from theoretical growth models they raise the question of whether fault growth earthquake recurrence rates and climate change can interact to produce semi regular discrete features in an active landscape

use of volume based 3 d seismic attribute analysis to characterize physical property distribution a case study to delineate sedimentologic heterogeneity at the appleton field southwestern alabama u s a abstract in this paper we illustrate the use of 3 d seismic attribute studies for predicting the distribution of physical properties in the subsurface using a data set consisting primarily of digital logs and seismic data we show how correlations can be made between seismic attributes and physical properties porosity and how those relationships can be exploited to predict the distribution of the property of interest in three dimensions the results of these studies 1 provide quantitative site specific 3 d models of physical properties that are of more use for applied studies than qualitative 2 d models commonly derived from facies modeling or sequence stratigraphic analysis 2 are generally more geologically reasonable than studies based on geostatistics alone 3 can provide sedimentary geologists with fundamental insights into depositional and or diagenetic controls on the distribution of properties of interest 4 need to be rigorously evaluated by integrating other types of data and analyses and 5 are best thought of as supplementing rather than replacing conventional geologic analyses the concepts and methods we illustrate may have application in various branches of sedimentary geology our study area is appleton field in southern alabama at this location we predict the 3 d distribution of porosity in carbonates of the upper jurassic smackover formation using a probabilistic neural network and a combination of four attributes our results suggest that porosity was best developed and preserved in thrombolite facies of the reef front

new seismotectonic data from an intraplate region focal mechanisms in the armorican massif northwestern france summary focal mechanism solutions are determined for 11 small intraplate earthquakes that occurred between 1990 and 1998 in normandy and the channel islands these mechanisms are obtained from the p wave first motion polarities recorded by stations from local and regional seismic networks the accuracy of each hypocentral location is closely examined and the quality of each fault plane solution is discussed by considering the influence of the velocity structure the predominant feature of the computed focal mechanisms is the relatively widespread near horizontal ne sw t axis orientation horizontal p axes strike roughly nw se mechanism solutions for the earthquakes in the avranches region show left lateral strike slip on a nnw sse fault zone for the overall region it seems that nodal planes of normal faulting solutions trend nw se or wnw ese whereas those of thrust faulting solutions trend ne sw this is in agreement with the general regional stress pattern the ne sw normal fault plane solution of the 1990 jersey event is unique because it is not consistent with the regional style of faulting

3d seismic reflection amplitude and instantaneous frequency attributes in mapping thin hydrocarbon reservoir lithofacies morrison ne field and morrison field clark county ks thin hydrocarbon reservoir facies pose resolution challenges and waveform signature opportunities in seismic reservoir characterization and prospect identification in this study we present a case study where instantaneous frequency variation in response to a thin hydrocarbon pay zone is analyzed and integrated with other independent information to explain drilling results and optimize future drilling decisions in morrison ne field some wells with poor economics have resulted from well placement incognizant of reservoir heterogeneities the study area in clark county kanas usa has been covered by a surface 3d seismic reflection survey in 2010 the target horizon is the viola limestone which continues to produce from 7 of the 12 wells drilled within the survey area seismic attributes extraction and analyses were conducted with emphasis on instantaneous attributes and amplitude anomalies to better understand and predict reservoir heterogeneities and their control on hydrocarbon entrapment settings we have identified a higher instantaneous frequency lower amplitude seismic facies that is in good agreement with distinct lithofacies that exhibit better higher porosity reservoir properties as inferred from well log analysis and petrographic inspection of well cuttings this study presents a pre drilling data driven approach of identifying sub resolution reservoir seismic facies in a carbonate formation this workflow will assist in placing new development wells in other locations within the area our low amplitude high instantaneous frequency seismic reservoir facies have been corroborated by findings based on well logs petrographic analysis data and drilling results

a late cenozoic regional mesofracture system in southern england and northern france the upper cretaceous and palaeogene rocks of s england and n france are cut by a nw trending system of fractures characterized by swarms of vertical extension joints accompanied by conjugate sets of hybrid and shear joints and normal mesofaults many major photolineaments exhibit the same nw trend as the fractures and are particularly conspicuous in n france where they are coincident with rectilinear drainage channels suggesting a relationship between fracture orientation and physiography in s england this relationship is absent possibly because of the influence of additional fracture systems related to major flexures trending obliquely to the nw se direction these major e w trending flexures and associated fracture systems were formed during the oligocene to early miocene 9helvetic9 phase of deformation and are cross cut obliquely by fractures in the nw trending system the nw trending fractures and lineaments are parallel to neotectonic normal faults in the lower rhine embayment and become less well developed to the west with increasing distance from these major structures the lower rhine faults were reactivated and propagated into the quaternary cover as a consequence of ne sw regional tension generated during the late neogene to recent 9jura9 phase of nw se alpine convergence the nw trending extensional structures in s england and n france are considered to be of about the same age and related to the same stress regime as the neotectonic normal faults of the lower rhine embayment however because fractures of the nw system cutting palaeogene sediments in se england are truncated by the erosion surface beneath the plio pleistocene red crag deposits it is possible that in england fracture initiation did not continue into quaternary times

gps seismology application to the 2002 mw 7 9 denali fault earthquake abstract the 2002 denali fault alaska earthquake m w 7 9 caused one or more components of most broadband seismometers in western canada to clip yet did not trigger strong motion instruments thus leaving a substantial gap in the seismic record of this event however the large amplitude surface waves generated by this event were well recorded by the global positioning system gps in the same region out to epicentral distances of more than 3000 km in this article we explore the capabilities of gps seismology specifically how the relative strengths of gps and seismic data sets can be exploited in order to more effectively study earthquake source characteristics and wave propagation effects high rate 1 hz gps data from 23 stations throughout western north america have been analyzed to derive displacement waveforms for this event and the impact of instrumentation gps receiver model and error reduction strategy modified sidereal and spatial filtering on the noise characteristics of displacement time series at each gps site was assessed after applying error reduction methods to gps displacements the final average noise floors of 0 5 cm in the horizontal and 1 5 cm in the vertical indicate that large dynamic displacements are observable by gps we validate the gps displacements by comparing broadband seismic recordings integrated to displacement with gps recordings for four effectively colocated sets of instruments we show excellent agreement between the unclipped seismic and gps recordings of the surface waves from the denali earthquake over the period range of 10 50 sec and for ground displacements exceeding about 1 0 cm thus a large gps displacement data set is now available for western north america an area where records of this event were previously missing or incomplete the final gps seismograms are archived at incorporated research institutions for seismology iris for public use in future studies of the 2002 denali earthquake

drainage network analysis and tectonics of mindanao southern philippines abstract mindanao southern philippines is the site of an active arc continent collision which began in the late pliocene the principal tectonic features are faults and blind folds and duplexes which are not easily detectable in this island on which 75 of the surface is covered by pleistocene and holocene sediments and volcanics a detailed study of the drainage pattern and its discontinuities in the agusan davao and the cotabato basins when compared with field data radar data and subsurface structures observed on seismic documents enables a correlation of distant seismic lines and features existing on the basin edges the drainage network analysis based on description and interpretation of drainage anomalies and frequency allows us to distinguish 1 subhomogenous drainage areas which correspond to areas bearing consistent geological characteristics and 2 drainage anomalies the results have been checked in the field and compared with the tectonic features in the mountainous areas the extension of these structures could then be traced confidently further towards the flat lowlands we point out the presence of two distinct anomaly directions that intersect in eastern mindanao 1 numerous nnw anomalies in the intra arc basin of agusan davao and both pacific and central cordilleras appear as young features in the morphology and are due to strike slip faults of the arc continent collision some of the faults have proven to be reactivated middle miocene faults related to the initial rifting of the agusan davao basin 2 n s anomaly directions are transpressive ridges due to the collision except one anomaly which corresponds to the trace of the philippine fault zone and connects with the collisional features in contrast the cotabato basin in western mindanao lies between two terranes of different nature in the cotabato basin area the nw and nnw anomaly directions are also present and similarly correspond to strike slip faults and thrust related folds respectively pull apart basins occur in places where sagging is evidenced an additional set of anomalies trends ene and corresponds to the active extensional field below the quaternary sediments some of the en echelon features corresponding to blind flat and ramps structures were identified these observations provide reference examples for the evolution of basins generated within the compressive and strike slip setting of accreted belts

the structural evolution of the english channel area the structural evolution of the english channel area is controlled by structure and particularly by the pre existing cadomian and variscan crustal discontinuities which have been reactivated repeatedly in post variscan times they controlled the crustal subsidence that produced basin development in the mesozoic prior to the sea floor spreading in the north atlantic region they were then reactivated during the cenozoic compression and basin inversion the english channel development is ascribed to mid tertiary differential uplift oligocene to miocene during late tertiary to quaternary times the channel displays characteristics of a tectonically controlled fluvial basin periodically invaded by the sea at the lithospheric scale the channel can be considered as an active intraplate area influenced by the nw se alpine push the nw se atlantic ridge push and glacial rebound stresses copyright 2003 john wiley sons ltd

analysis of long period seismic waves excited by the may 18 1980 eruption of mount st helens a terrestrial monopole long period 100 to 260 s love and rayleigh waves excited by the eruption of mount st helens on may 18 1980 and recorded by ida sro and asro stations were analyzed to determine the mechanism of the eruption the amplitude radiation patterns of both rayleigh and love waves are two lobed with a nodal direction in e5 s for rayleigh waves and in n5 e for love waves these radiation patterns preclude any double couple mechanism the radiation pattern the initial phase the relatively large amplitude ratio of love to rayleigh waves and the existence of clear nodes in the radiation patterns of fundamental mode and higher mode rayleigh waves suggest that the source is represented by an almost horizontal less than 15 from the horizontal single force pointed toward s5 w the surface wave spectra fall off very rapidly at periods shorter than 75 s suggesting a very slow source process although the details of the source time history could not be determined a smooth bell shaped time function f o s t 1 2 f o l cos t for 0 t 2 and f o s t 0 for t 2 with 75 s is considered appropriate on the basis of comparison between synthetic and observed seismograms and of the shape of the source spectrum the peak value of the force f 0 is about 10 18 dynes the tailing end of the source time function could not be resolved and some overshoot may be added the magnitude and the time history of the force can be explained by a northward landslide followed by a lateral blast observed at the time of the eruption two distinct events about 110 s apart can be identified on body wave and short period surface wave records the first event may correspond to the earthquake which triggered the landslide and the lateral blast the second event appears to correspond to a second large earthquake and explosion which took place about 2 minutes after the first earthquake

using multi attribute neural networks classification for seismic carbonate fades mapping a workflow example from mid cretaceous persian gulf deposits abstract seismic facies mapping in large seismic surveys can be time consuming even if only a basic overview of the facies distribution is needed therefore this study outlines an approach for the use of volume based seismic attributes from 2d surveys for automated seismic facies mapping within carbonate settings the study area is located in the central persian gulf offshore iran the interval of interest is the mid cretaceous sarvak formation which is part of the extensive cretaceous shallow water carbonate platform of the eastern arabian plate a set of nine volume based seismic attributes calculated from time amplitude and frequency information of post stacked 2d seismic data was chosen to characterize geological information within the interval of interest the volume based attributes were supplemented by two grid based attributes to highlight structural elements the geological significance of each attribute was evaluated by comparing it with results of seismic sedimentological geomorphological studies furthermore statistical methods were applied to highlight direct relationships amongst the attributes the results of these tests were then used to choose a limited set of attributes for neural network based multi attribute classifications the results show that seismic attributes derived from 2d surveys can be used to map basic seismic facies types in carbonate settings and that the outlined general approach might be applied in other studies

regional variations in tectonic geomorphology along a segmented convergent plate boundary pacific coast of costa rica abstract pacific coastal mountain piedmont landforms of costa rica extend across the tectonic boundary between the forearc and magnetic arc region of an active convergent margin this plate boundary became segmented circa 1 million years ago when the aseismic cocos ridge impinged upon the middle america trench offshore from the southernmost coastal area of costa rica morphometric analyses of 100 mountain fronts and numerous river long profiles radiometric dating and field studies were conducted in two study areas located arcward from the plate boundary where oceanic lithosphere of the cocos plate is being subducted beneath the caribbean plate region i and the partially subducted aseismic ridge is uplifting the plate margin by isostatic and collisional processes region ii values of tectonic geomorphic parameters mountain front sinuosity s percent dissected facets ffd river concavity k are not only different statistically in regions i and ii but are also different in the areas experiencing isostatic and collisional responses to the subducting aseismic ridge in the area experiencing collisional responses mountain fronts developed along ne dipping imbricate thrust and high angle reverse faults step upward and inland from the coast morphometric data along with the divergence of river terrace profiles from the coast piedmont inland toward the mountains indicates higher uplift rates along interior range mountain fronts isostatic uplift in the outer forearc area in region ii produces a distinctly different morphologic and neotectonic style characterized by regional uplift distributed across a number of blocks bounded by normal faults geomorphic analyses indicate a general southward trend of increasing tectonic uplift from region i into region ii where the highest frequency of mountain fronts with low values of s and ffd as well as rivers with the highest values of k occur over the crest of the subducted ridge field and historical seismic data for these regional trends include 1 fault scarps displacing late quaternary fluvial terraces and colluvial soils in areas of collisional responses 2 holocene latest pleistocene marine sediments uplifted tens of meters along normal faults in areas of isostatic response of region ii and 3 more frequent shallow high magnitude earthquakes in region ii this study indicates that spatial variations in the plate tectonic framework can be detected by regional morphometric analyses using techniques applied in extensional and compressional terranes of arid and semiarid regions but not previously applied to forearc systems along convergent plate boundaries in tropical areas

tectonic control of the tejo river fluvial incision during the late cenozoic in rodao central portugal atlantic iberian border staircases of strath terraces and strongly incised valleys are the most typical landscape features of portuguese rivers this paper examines the incision achieved during the late cenozoic in an area crossed by the tejo river between the border with spain and the small town of gaviao in the more upstream reach of this area the tejo crosses the rodao tectonic depression where four levels of terraces are distinguished during the late cenozoic fluvial incision stage the rodao depression underwent less uplift than the adjacent areas along the river this is reflected by the greater thicknesses and spatial extent of the terraces terrace genesis was promoted by impoundment of alluvium behind a quartzitic ridge and the local presence of a soft substratum outside this tectonic depression the tejo has a narrow valley incised in the hercynian basement with some straight reaches that probably correspond to ne swand nnw sse faults the terraces being nearly absent geomorphological evidence of tectonic displacements affecting the rodao dissected terrace remnants is described geochronological dating of the two younger and lower terrace levels of this depression suggests a time averaged incision rate for the tejo in the rodao area of ca 1 0 m ka over the last 60 thousand years a clear discrepancy exists between this rate and the 0 1 m ka estimated for the longer period since the end of the pliocene although episodes of valley incision may be conditioned by climate and base level changes they may also have been controlled by local factors such as movement of small fault bounded blocks lithology and structure regional crustal uplift is considered to be the main control of the episodes of valley incision identified for this large long lived river a model is proposed in which successive regional uplift events tectonic phases essentially determined the long periods of rapid river downcutting that were punctuated by short periods of lateral erosion and later by some aggradation producing strath terraces d 2004 elsevier b v all rights reserved

offsets of late quaternary morphology rate of slip and recurrence of large earthquakes on the chang ma fault gansu china the chang ma fault in the western qilian shan gansu province shows evidence of consistent left lateral displacements despite a complex en echelon geometry we have measured short and long term offsets on two n70 80 e striking segments of the fault along the southern edge of the ta quen kou basin where it cuts late quaternary terraces transverse ridges and drainage channels to analyze the offsets of such structures at one site in the eastern part of the basin we ran topographic profiles parallel and perpendicular to the fault over a distance of about 5 km spectral analysis and comparison of longitudinal profiles north and south of the fault allowed us to separate horizontal offsets of structures of different wavelengths apparent on air photos and satellite images transverse profiles were used to determine the vertical throw whose variations appear to result from changes in the fault strike small horizontal offsets of ridge crests and valley slopes are about 55 m along the n70 e striking segment of the fault this displacement corresponds to an uplift of the northern block of about 27 m implying that the fault dips about 73 to the south the measurements also constrain horizontal projection of the slip vector to about n78 e a larger horizontal offset 500 m of morphological swells of longer wavelength 1 6 km is visible on the longitudinal profiles assuming that periglacial erosion has reshaped the surface of the lateral slopes and tops of ridges during the wurm glacial period the smallest offsets of adjacent ridge crests may postdate the begining of the holocene yielding an average rate of left lateral slip on the fault of 5 5 2 2 mm yr in the last 10 2 kyr in the western part of the ta quen kou basin a somewhat slower rate of holocene slip 4 6 4 mm yr is obtained measurement of the horizontal displacement due to the 1932 earthquake there 6 2 0 6 m would imply that the recurrence interval for similar earthquakes at this second site is 1350 540 years

geomorphic response of coastal streams to low intermediate and high rates of uplift medocino triple junction region northern california analysis of three dimensional morphological properties of 24 coastal drainage basins that have evolved in areas of low 3 m 1 000 yr rates of uplift near the mendocino triple junction mtj coastal northern california identified channel gradients as the best indicator of tectonism in the landscape lower order tributaries best reflect tectonically controlled differences the largest streams examined of third order are able to adjust to most base level change and maintain their profile form whereas lower order streams farther upstream tend to accumulate the effects of net base level fall and have steepest profiles in the areas of highest uplift rates variations in steepness of first order channel gradients indicate that 1 high uplift rates in the wake of the mtj have existed for at least 73 000 yr and 2 differential tilt of the region to the north and south of the current locus of highest uplift rate is occurring in association with regional uplift although first order streams are excellent indicators of areas of both high uplift rates and regional differential tilting they are less useful in distinguishing between areas of low and intermediate uplift rate analysis of the longitudinal profile of the main trunk stream of ten of the 24 drainage basins using the stream gradient index was more useful to categorize broadly the uplift rates and to distinguish between streams in low and intermediate uplift rate areas although the hypotheses tested herein do not identify the exact mechanism off uplift in the mtj region they do indicate that the nature of deformation is most likely regional tilt rather than crustal shortening with localized compressional folding and thrust faulting they also indicate that geomorphic responses trail in the wake of the uplift rate response caused by development of a slab window beneath the north american plate 1 maximum uplift rates occur 9 km south of the northern boundary of the slab window 2 maximum mean first order channel gradient occurs 16 km south of the northern edge of the slab window and 3 maximum drainage basin relief occurs 20 km south of the northern edge of the slab window associated lag times between passage of the southern edge of the subducted gorda plate slab and geomorphic responses are 160 000 yr for maximum uplift rates 290 000 yr for maximum channel gradients and 370 000 yr for maximum relief

ground deformation cycles in a magma effusive stage and sub plinian and vulcanian eruptions at kirishima volcanoes japan 1 the dynamics of explosive eruptions such as plinian sub plinian vulcanian and strombolian ones is one of the most fascinating subjects in volcano physics during the early period of volcanic activity at the shinmoe dake volcano in 2011 various kinds of activities such as sub plinian eruptions a magma effusion and vulcanian eruptions occurred sequentially a different kind of tilt motion accompanied each activity here we clarify the characteristics of the tilt motions and their time sequences presenting a new explanation of the triggering mechanism of a vulcanian eruption the sub plinian and the vulcanian eruptions at the shinmoe dake volcano were preceded by inflations at shallow depths near the summit the inflation deflation cycles were also recorded during the magma effusive stage with a typical period of 1 h synchronized with volcanic tremors or long period events almost all vulcanian eruptions were preceded by trapezoidal inflations whose durations systematically lengthened as time progressed and were followed by various time sequences of tilt motions which became increasingly more complicated throughout the frequent vulcanian eruptions we have found clear linearity with a constant gradient of 0 45 between the logarithm of the preceding duration versus elapsed time for each substage these observations can be consistently explained based on the assumption that a vulcanian eruption is induced by a catastrophic rupture of the strongest closed solid magma frame due to magma degassing overpressure and the degassing from magma declines exponentially with time

analysis and interpretation of seismic data from thin reservoirs northwest java basin indonesia a detailed analysis and interpretation is performed of a 2 d seismic line over a sequence of thin reservoirs in the upper cibulakan formation in the northwest java basin most well sites in this area are selected to be structures near fault zones as faults are assumed to be the main hydrocarbon migration paths amplitude variation with offset analysis is little used because of contamination by thin layer tuning effects attribute analysis impedance inversion and full wavefield modeling suggest that gas reservoirs are detectable even when they are less than their tuning thickness as they correspond to acoustic impedance anomalies and low instantaneous frequency the presence of hydrocarbons can also be detected by anomalous behavior in crossplots of acoustic impedance versus density and p wave velocity sandstone reservoirs show low velocity and low impedance two dimensional p velocity and density distributions resulting from impedance inversion produce synthetic elastic common source gathers that disp

seismic attribute technology for reservoir forecasting and monitoring during the 1970s and 1980s the seismic attributes most used in petroleum exploration were amplitude based instantaneous attributes however in the 1990s seismic attribute technology has dramatically advanced in several directions techniques now range from single trace instantaneous event attribute computations to more complex multitrace windowed seismic event attribute extractions to the generation of seismic attribute volumes applications run from simple amplitude anomaly detection to monitoring fluid front movement over time

evaluating the structure characteristics of epikarst at a typical peak cluster depression in guizhou plateau area using ground penetrating radar attributes abstract epikarst defined as the skin of karst environment is widely developed in southwest china largely as a result of the subtropical monsoon climate typical sw china karst accommodates a dual hydrogeological structure with surface and subsurface hydrological systems the epikarst ecosystem of karst environments plays a key role in biogeochemical cycling and energy and material storage and transport due to low rates of soil formation derived from carbonate rock weathering the soil layer is shallow and scattered presenting interlocked features within carbonate rock research on epikarst structure is primarily based on section field survey with semi quantitative characterization often lacking a fully quantitative description of soil rock structural characteristics we utilized ground penetrating radar gpr attributes to interpret the structure of epikarst at a peak cluster depression in the guizhou karst plateau two typical types of epikarst slope profiles and one peak cluster depression in maguan town puding county were selected for study we used mala gpr equipment with 500 mhz and 50 mhz antennas to acquire data gpr data was processed conventionally and then average energy attributes average amplitude attributes and coherence attributes were extracted to interpret the structure of the two epikarst profiles and the soil depth of the depression the results show that i energy and coherence attributes can highlight the soil rock structure of the epikarst profiles with relative ease ii compared to the original returned image the energy attributes visualise the soil and rock medium more effectively and iii the coherence attributes can identify the reflection interface between complete bedrock and bedrock containing fissure and grikes epikarst in addition using the 50 mhz antenna we were able to determine the soil depth in depression with coherence attributes indicating a depth of 3 6 m very close to the real depth 3 58 m measured by our auger verification work gpr attributes provide evidence that the epikarst has developed a large number of fissures filled with soil or other materials but that the bedrock under the epikarst has few fractures gpr attributes are therefore helpful for increasing our confidence of studying the structure of slope epikarst structure and depression soil depth

analysis of the interaction between neotectonic and surface processes in a low land intracratonic setting of south america abstract the quaternary sedimentary record in the continental interiors has generally been studied taking into consideration the climatic forcing however episodes of uplift controlling the development of landforms have often been dismissed the interiors of continents are typically considered to have low deformation rates lower than the rates of exogenous processes deformation in the middle of the pampean plains an intracratonic setting of south america has been observed to have generated an elevated area surrounded by lowland plains this elevated area is susceptible to fluvial erosion from this fact we developed a geomorphologic modelling constrained from geomorphic markers in order to estimate the relative incidence of the different factors that control erosion in lowland landscapes an adapted erosion code was employed which combines fluvial incision equation the stream power law an uplift function spatially distributed and the hillslope diffusion equation a low dem was achieved for restoring an initial non deformed topography affected by low fluvial incision it represents a palaeosurface chrono stratigraphically constrained the estimation of the model parameters was achieved by applying the inversion method the best fit between the numerical solution calculated topography and the measured topography simulated by means a dem was approached by comparison of the stream longitudinal profiles the yield numerical approach suggests that a geomorphological modelling based on the stream power law is possible to be applied in low land landscapes for this a large scale change of the magnitude of the processes modelling the landscape should be expected in comparison with mountain erosional environments remarkably low k empirical values k 5 10 6 6 10 6 yr 1 suggest that the extremely low slopes exert a larger influence on the stream power in low land landscapes also the diffusion coefficient d values resulted largely lower 3 10 4 1 9 10 3 cm 2 yr than presented in tectonically active landscapes 0 03 cm 2 yr regional uplift rates can be higher 0 35 mm yr than it is generally expected in low uplift rate settings 0 1 0 25 mm yr these estimations evidence highly dynamic surface and tectonic processes controlling the landscape evolution over intermediate time scales in an intracratonic setting

tectonic eustatic and climatic significance of raised beaches of val de saire cotentin normandy france detailed mapping morphostratigraphical and geochronological analyses were undertaken in the val de saire cotentin normandy northern france these studies have identified a series of middle and upper pleistocene age deposits overlying four wave cut platforms pf iv pf i which can be associated with temperate high sea level events and equated with mis 11 9 7 and mi substage 5e a sea level stand recorded at 20 m ngf at the la mondree site seems to correspond to mi substage 5c or 5a the completeness of the val de saire record and particularly the width of platform iv mis 11 has so far no equivalent on the south coast of the english channel this study provides contribution to an understanding of the impact of the interglacial glacial cycles in a coastal intraplate situation the cyclicity of the morphogenesis is explained by interaction between eustatic variations and strongly expressed activity of slow uplift ca 60 mm kyr through the middle pleistocene several osl dates from the gravel to sand sequence of the eemian weichselian cycle indicate that these deposits represent the marine regression of the end of the last interglacial

tilt signals derived from a geoscope vbb station on the piton de la fournaise volcano we report some very long period transients observed on a very broadband seismic station of the geoscope network which is situated 8 km away from the summit of the piton de la fournaise volcano we transform the ground velocity measured by the seismic station into tilt and test the result by comparing with data from blum type classical pendulum tiltmeters located in the same vault the comparison validates the use of the horizontal seismometers for measuring tilt for periods shorter than 25 hours the method is applied to the transients observed prior to several eruptions and magmatic intrusions since 1991 because of the moderate distance between geoscope station and the summit of the volcano the obtained tilt measurements provide information about eruptions and intrusions which complement the information on the geometry and location of the magmatic source provided by the summit tilt network

intraplate seismicity new seismotectonic data in western europe abstract fault plane solutions for 128 earthquakes which occurred in france and neighbouring areas have been determined stress field information given by these data are discussed in relation to previous tectonic knowledge the western alps are characterized by a compressional regime with a fan shaped distribution of p axes which might be related to the interaction mechanism between europe and the adriatic plate the pyrenean region is mainly submitted to a south north compression tectonic activity in this area seems to be determined by the presence of two subduction zones with reverse dips in the south bay of biscay and in the central pyrenees the transition zone between these two active belts is characterized by significant seismicity with a transpression regime

characterization of a deeply buried paleokarst terrain in the loppa high using core data and multiattribute seismic facies classification the recognition of paleokarst in subsurface carbonate reservoirs is not straightforward because conventional seismic interpretation alone is generally not sufficient to discriminate karstified areas from their surroundings in the loppa high norwegian barents sea a protracted episode of subaerial exposure occurring between the late paleozoic and mid triassic late permian to anisian resulted in a significant overprinting of the previously deposited carbonate units here we map the extension of the karstified areas using an integrated approach consisting of 1 a core study of critical paleokarst intervals 2 a three dimensional 3 d seismic stratigraphic analysis and 3 a 3 d multiattribute seismic facies sf classification a core retrieved in the flat topped loppa high revealed breccia deposits at least 50 m 164 ft thick which probably resulted from cave collapses following the burial of the karst terrain the sf classification was tested on a 3 d cube to 1 discriminate the respective sf related to the breccia deposits compared with other sf and 2 to estimate their spatial extent seismic facies analysis suggests that breccias occupied the topmost area of the structural high extending up to 12 km 7 mi in width 46 km 29 mi in length and tens of meters in thickness the inference of such a large amount of breccia suggests that a significant part of this terrain was derived from the amalgamation of successive cave development events including periods of subaerial exposure and subsequent burial and collapse resulting in a coalesced collapsed paleocave system previous observations from the loppa high revealed the presence of karst plains associated with sinkholes caves and other dissolution phenomena associated with the breccia facies further suggesting that a large volume of carbonate rocks in this area was affected by subaerial exposure and karstification our integrated approach and proposed karstification model could be applied to similar sedimentary basins that accommodate deeply buried carbonate successions affected by protracted episodes of subaerial exposure where only few wells as well as 3 d seismic data are available

two stage evolution of the cenozoic kunbei fault system and its control of deposition in the sw qaidam basin china the structural relationship between the qaidam basin and qimen tagh eastern kunlun range holds important implications for evaluating the formation mechanism of the tibetan plateau various models have been proposed to reveal the structural relationship although controversies remain to address these issues we analysed the seismic and lithologic data of the kunbei fault system i e the kunbei arlar and hongliuquan faults which lies to the north of the qimen tagh eastern kunlun range within the sw qaidam basin based on the regional geological framework and our kinematic analyses we propose that the cenozoic tectonic evolution of the kunbei fault system can be divided into two stages from the early eocene to the middle miocene the system was characterized by left lateral strike slip faults and weak south dipping thrust faults based on the flower structure in the seismic section which is an apparent strike slip deformation that was identified in the 1510 ms time slice and the root mean square amplitude attribute slice this strike slip motion was generated by the uplift of the tibetan plateau caused by the onset of the indian eurasian collision since the middle miocene the kunbei fault system has undergone intense south dipping thrusting and a nearly 2 2 km uplift has been observed in the hanging wall in the arlar fault the south dipping thrusting is the far field effect of the full collision that occurred between the indian eurasian plates the lake area in the sw qaidam basin has been shrinking since the middle miocene and presents widespread delta and fluvial deposits which are consistent with the proposed tectonic evolution

neotectonics and intraplate continental topography of the northern alpine foreland research on neotectonics and related seismicity has hitherto been mostly focused on active plate boundaries that are characterized by generally high levels of earthquake activity current seismic hazard estimates for intraplate domains are mainly based on probabilistic analyses of historical and instrumental earthquake catalogues the accuracy of such hazard estimates is limited by the fact that available catalogues are restricted to a few hundred years which on geological time scales is insignificant and not suitable for the assessment of tectonic processes controlling the observed earthquake activity more reliable hazard prediction requires access to high quality data sets covering a geologically significant time span in order to obtain a better understanding of processes controlling on going intraplate deformation the alpine orogen and the intraplate sedimentary basins and rifts in its northern foreland are associated with a much higher level of neotectonic activity than hitherto assumed seismicity and stress indicator data combined with geodetic and geomorphologic observations demonstrate that deformation of the northern alpine foreland is still on going and will continue in the future this has major implications for the assessment of natural hazards and the environmental degradation potential of this densely populated area we examine relationships between deeper lithospheric processes neotectonics and surface processes in the northern alpine foreland and their implications for tectonically induced topography for the environmental tectonics project entec the upper and lower rhine graben urg and lrg and the vienna basin vb were selected as natural laboratories the vienna basin developed during the middle miocene as a sinistral pull apart structure on top of the east alpine nappe stack whereas the upper and lower rhine grabens are typical intracontinental rifts the upper rhine graben opened during its late eocene and oligocene initial rifting phase by nearly orthogonal crustal extension whereas its neogene evolution was controlled by oblique extension seismic tomography suggests that during extension the mantle lithosphere was partially decoupled from the upper crust at the level of the lower crust however whole lithospheric folding controlled the mid miocene to pliocene uplift of the vosges black forest arch whereas thermal thinning of the mantle lithosphere above a mantle plume contributed substantially to the past and present uplift of the rhenish massif by contrast oblique crustal extension controlling the late oligocene initial subsidence stage of the lower rhine graben gave way to orthogonal extension at the transition to the neogene the entec project integrated geological geophysical geomorphologic geodetic and seismological data and developed dynamic models to quantify the societal impact of neotectonics in areas hosting major urban and industrial activity concentrations the response of europe s intraplate lithosphere to late neogene compressional stresses depends largely on its thermo mechanical structure which in turn controls vertical motions topography evolution and related surface processes

seismic attributes a historical perspective a seismic attribute is a quantitative measure of a seismic characteristic of interest analysis of attributes has been integral to reflection seismic interpretation since the 1930s when geophysicists started to pick traveltimes to coherent reflections on seismic field records there are now more than 50 distinct seismic attributes calculated from seismic data and applied to the interpretation of geologic structure stratigraphy and rock pore fluid properties the evolution of seismic attributes is closely linked to advances in computer technology as examples the advent of digital recording in the 1960s produced improved measurements of seismic amplitude and pointed out the correlation between hydrocarbon pore fluids and strong amplitudes bright spots the introduction of color printers in the early 1970s allowed color displays of reflection strength frequency phase and interval velocity to be overlain routinely on black and white seismic records interpretation workstations in the 1980s provided

a point pattern analysis of the distribution of earthquakes in normandy france abstract a new mathematical method has been developed to guide the interpretation of sparse epicenter distributions the aim of the technique is the assessment of the significance of epicenter alignments this assessment is connected to the detection of seismic faults the method has been tested on synthetic data sets and on seismicity from the san francisco bay area these tests show high detection capabilities when the method is applied to actual data in order to discard artificial lines the interpreter must check the results using geological information the method is applied to epicenters in western normandy the main structural directions of normandy are tracked by sparse epicenters

volcanic processes detected by tiltmeters a review of experience on sicilian volcanoes abstract a review of the experience gained in the use of tiltmeters on mt etna stromboli and vulcano during the last 30 years is reported here tilt data represent a fundamental contribution towards understanding volcanic processes such as dike intrusions fracture propagation lava fountains and volume changes in magmatic or hydrothermal systems causing a deflation inflation of the edifice intrusive processes preceding lateral eruptions show large variations up to over 100 microradians while minor variations not exceeding 2 5 microradians are linked to lava fountains that form ash plumes and lead to fallout deposits that cause severe hazards to aviation high precision tilt also allows detecting the slight ground deformation linked to strombolian activity 0 01 0 2 microradians as well as co seismic variations 0 1 1 5 microradians and tidal effects 0 1 0 2 microradians that may have a role in the evolution of a volcanic system time amplitude tilt ranges linked to each process are generally different allowing to discriminate in real time between a signal associated to one process and another one this fact is important in terms of early warning particularly during the first phases of dikes propagation that precede a lateral eruption by hours days

seismic facies analysis based on speech recognition feature parameters abstractseismic facies analysis plays an important role in seismic stratigraphy seismic attributes have been widely applied to seismic facies analysis one of the most important steps is to optimize the most sensitive attributes with regard to reservoir characteristics using different attribute combinations in multidimensional analyses will yield different solutions acoustic waves and seismic waves propagating in an elastic medium follow the same law of physics the generation process of a speech signal based on the acoustic model is similar to the seismic data of the convolution model we have developed the mel frequency cepstrum coefficients mfccs which have been successfully applied in speech recognition as feature parameters for seismic facies analysis information about the wavelet and reflection coefficients is well separated in these cepstrum domain parameters specifically information about the wavelet mainly appears in the low domain part and information about the reflection coefficients

porosity prediction from seismic attributes of the ordovician trenton black river groups rochester field southern ontario this article integrates three dimensional 3 d seismic attributes and log data to determine porosity distribution of the ordovician trenton black river groups within the rochester field southern ontario the rocks are composed of tight limestone parts of which were dolomitized to form porous reservoir rock previous studies of the trenton black river dolomite reservoirs have indicated a close relationship between faulting and reservoir development but few published studies have attempted to examine these relationships using 3 d seismic data this study explores the stratigraphy and structure of the rochester fault related dolomite reservoir using 3 d seismic data and neural networks to predict porosity by predicting porosity using seismic attributes vertical and lateral distributions of porosity that can be used to guide development and exploration drilling for optimal hydrocarbon recovery were obtained the sites of highest porosity were found to be along and within the fault zones faults extending from the basement into overlying paleozoic rocks are composed of several short plane vertical and subvertical fault segments however some of these faults appear to have originated and died within the paleozoic rocks they cannot be traced to the basement because of little or no offset where they penetrate the basement although the five identified attributes are considered important in exploration for fault related dolomite reservoirs the single most important attribute to employ is the amplitude envelope because the other attributes are mathematically related to it furthermore the sags that are seen in the rochester field are due to the combined effects of low velocity pushdown and faulting methods and results presented in this study can be used to explore and develop fault related dolomite reservoirs elsewhere in similar geologic settings

active tectonics in southern xinjiang china analysis of terrace riser and normal fault scarp degradation along the hotan qira fault system the northern piedmont of the western kunlun mountains xinjiang china is marked at its easternmost extremity south of the hotan qira oases by a set of normal faults trending n50e for nearly 70 km conspicuous on landsat and spot images these faults follow the southeastern border of a deep flexural basin and may be related to the subsidence of the tarim platform loaded by the western kunlun northward overthrust the hotan qira normal fault system vertically offsets the piedmont slope by 70 m highest fault scarps reach 20 m and often display evidence for recent reactivations about 2 m high successive stream entrenchments in uplifted footwalls have formed inset terraces we have leveled topographic profiles across fault scarps and transverse abandoned terrace risers the state of degradation of each terrace edge has been characterized by a degradation coefficient derived by comparison with analytical erosion models edges of highest abandoned terraces yield a degradation coefficient of 33 4 m 2 profiles of cumulative fault scarps have been analyzed in a similar way using synthetic profiles generated with a simple incremental fault scarp model the analysis shows that 1 rate of fault slip remained essentially constant since the aggradation of the piedmont surface and 2 the occurrence of inset terraces was synchronous at all studied sites suggesting a climate driven terrace formation observation of glacial and periglacial geomorphic features along the northern front of the western kunlun range indicates that the qira glaciofluvial fan emplaced after the last glacial maximum during the retreat of the kunlun glaciers 12 22 ka the age of the most developed inset terrace in uplifted valleys is inferred to be 10 3 ka coeval with humid climate pulses of the last deglaciation the mass diffusivity constant k t being time b p in the hotan region is determined to be 3 3 1 4 m 2 10 3 years consistent with other estimates in similar climatic and geologic environments of western china these results imply a minimum rate for the tarim subsidence of 3 5 2 mm yr if western kunlun overthrusts the tarim platform on a crustal ramp dipping 40 45 to the south it would absorb at least 4 5 3 mm yr of convergence between western tibet and tarim

thermomechanical structure of european continental lithosphere constraints from rheological profiles and eet estimates summary the eet equivalent elastic thickness of the lithosphere is a measure of the integrated lithospheric strength it is directly related to the mechanical thickness and rheology of the crustal and mantle lithosphere we present a comparison of eet estimates and strength profiles based on the extrapolation of rock mechanics data for different parts of the european and eurasian continental lithosphere we discuss the temporal and spatial variations in the mechanical thickness and strength inferred from data for precambrian segments of europe s lithosphere variscan europe and the alpine collision belt this analysis demonstrates important spatial and temporal variations in lithospheric rigidity for orogenic belts and sedimentary basins in eastern and western europe and asian parts of eurasia the eet estimates based on synthetic rheological profiles constrained by newly available geophysical data are consistent with the estimates of eet derived from flexural studies of sedimentary basins forelands and orogenic belts these rheological profiles suggest weakening of the major parts of the european and eurasian continental lithosphere by decoupling of the crustal and upper mantle parts a comparison with the seismicity depth distribution for some selected sites suggests that the intra plate seismicity is essentially restricted to the upper crustal parts of europe s lithosphere providing additional support to the notion of the decoupled lithosphere the presence of intra plate stress fields can explain a significant part of the observed variations in eet estimates within individual thermotectonic age groups a comparison of wavelengths of crustal and lithospheric folding with observations shows these wavelengths to be consistent with estimates of eet inferred from the rheological response of basins and orogens at more moderate levels of intra plate stress

geophysical evidence for structurally controlled authigenic carbonate cementation in the laminaria high bonaparte basin northwest shelf of australia abstract 3d seismic reflection data are used to investigate the processes which have led to the development of amplitude anomalies on reflectors in the faulted cenozoic overburden on the laminaria high northwest shelf of australia amplitude and root mean square rms attributes are mapped on two reflectors seabed and horizon h9 that were deposited synchronous with fault activity and are located adjacent to predominantly ene wsw striking fault traces on the seabed the main anomaly is located on the up dip side of the fault trace and is elongated parallel to the local time structure contours these observations are consistent with the anomalies having developed in response to structurally controlled fluid seepage along and up dip migration away from the fault trace the other amplitude anomalies associated with the h9 reflector are also located adjacent to fault traces but are discordant to the local time structure contours the latter observation is inconsistent with the migration of buoyant fluid at the present day instead it suggests that the anomalies may be due to cemented hardgrounds that formed due to seepage when the faults intersected the palaeo seafloor but were subsequently buried and deformed during ongoing sedimentation and fault growth linkage prominent anomalies mapped on reflectors within the pre faulting succession h10 are located adjacent to and are elongated along sub seismic scale nw se striking faults or as in the case of a deeper horizon h13 show no clear relationship with the faults we conclude that there is no relationship between the occurrence of anomalies and the magnitude of throw or the duration of activity along the cenozoic faults the results suggest that whilst fluid seepage and cementation were structurally controlled these processes were also influenced by permeability variations that cannot be resolved by seismic interpretation methods

geometry and kinematics of active normal faults south oquirrh mountains utah implication for fault growth the nnw striking south oquirrh mountains normal fault zone consists of four individual faults the individual faults are arranged in a right stepping pattern in the north and a left stepping pattern in the south forming a convex shaped fault zone in map view with the apex towards the hanging wall late quaternary fault activity is characterized by 2 0 4 5 m high discontinuous fault scarps developed in both late quaternary alluvium and bedrock the fault scarps in bedrock contain evidence of two large rupture events the last large earthquake occurred prior to the highstand of the bonneville lake cycle 15 ka based on cross cutting relationship between the bonneville shoreline and the fault scarp and on comparisons of fault scarp morphology cumulative displacement patterns inferred from range crest elevations bouguer gravity data in the adjacent basin and rotation of the subsidiary faults adjacent to the west mercur fault are similar to the pattern of displacements measured across late quaternary fault scarps that is the maximum displacement is near the apex of the convex shaped fault zone where the west mercur fault is located and then tapers off towards both ends of the fault zone fault traces that range from a few meters to tens of kilometers long are characterized by two dominant orientations strike n11 w and n43 w the two orientations are separated from each other by a statistically constant angle of 33 3 slip directions concentrate on a trend of s70 w for both groups of faults perpendicular to the average strike of the fault zone these data indicate that the geometry of the fault surfaces is non cylindrical and may be composed of self similar structural ridges and troughs of variable wavelength and amplitude that are elongated parallel to slip direction the relationships between fault geometry displacement and geomorphology in the south oquirrh mountains fault zone suggests a growth model of normal faults in which apex points on the convex shaped fault sections mark the nucleation points of primary faults secondary faults developed at the ends of the primary fault step into the footwall block as the fault zone grows laterally intersecting regions between two laterally growing fault zones are concave shaped in map view

new observations of displacement steps associated with volcano seismic long period events constrained by step table experiments long period lp volcano seismic events often precede volcanic eruptions and are viewed with considerable interest in hazard assessment they are usually thought to be associated with resonating fluid filled conduits although alternative models involving material failure have recently been proposed through recent field experiments we uncovered a step like displacement component associated with some lp events outside the spectral range of the typically narrow band analysis for this kind of event bespoke laboratory experiments with step tables show that steps of the order of a few micrometers can be extracted from seismograms where long period noise is estimated and removed with moving median filters using these constraints we observe step like ground deformation in lp recordings near the summits of turrialba and etna volcanoes this represents a previously unobserved static component in the source time history of lp events with implications for the underlying source process

origins of the european regional stress field abstract we present a study of the origins of the european regional stress field intraplate stresses due to various plate boundary forces and intraplate stress sources were predicted using an elastic finite element analysis the finite element mesh consists of about 1629 nodes in a network of 3117 triangular elements which provide a spatial resolution of about 1 the study builds on the previous modelling studies through consideration of a wide range of plausible forces acting along the collisional eastern and southern plate boundaries and importantly through the inclusion of forces due to other lateral density variations within the lithosphere such as those associated with the continental margins and high topography the modelling was constrained by more than 1800 stress indicators from the world stress map project which provide information about the orientation of the observed maximum horizontal compressive stress sh the torque associated with the ridge push force is well constrained and the principal source of uncertainty relates to the boundary conditions used to represent the collisional resistance acting along the eastern and southern boundaries a gradient in the collisional resistance increasing in magnitude from west to east is assumed to act along the southern plate boundary whereas the eastern boundary is modelled as a pinned margin at 46 e the sh orientation and magnitude of the regional stress field was found to be largely invariant to the boundary conditions used to represent the tectonic forces acting along the eastern and southern margins and is characterized by a nearly uniform nw se compression with a magnitude in the range of 10 20 mpa averaged over a 100 km thick lithosphere lateral density variations within the continental areas of europe were found to reduce the magnitude of the predicted stresses but do not have a significant effect on the orientation of the regional stress field

three dimensional seismic based definition of fault related porosity development trenton black river interval saybrook ohio oil and gas reservoirs of the ordovician trenton black river interval in the appalachian basin are commonly associated with fault related hydrothermal dolomites however relationships between porosity development and fault geometry in these fields are poorly documented in this article we integrate three dimensional 3 d seismic and wire line data from the trenton black river interval at saybrook field in northeastern ohio to study relationships between faulting and porosity development there faults were mapped using a combination of amplitude and coherency versions of the seismic data and a 3 d porosity volume was generated for the trenton black river interval by integrating attributes derived from the seismic data with log based measures of porosity the productive trend in the trenton black river interval at saybrook is controlled by a 3 4 mi 5 5 km long northwest southeast oriented basement fault that was probably reactivated during the taconic orogeny i e late ordovician strike slip movement along the fault generated en echelon synthetic shear faults that branch at least 1350 ft 411 5 m upward into the trenton black river interval the best porosity is developed in areas between overlapping synthetic shear faults antithetic shear faults probably formed at these locations and when combined with minor dip slip movement created conduits for subsequent porosity generating fluids circular collapse structures associated with localized extension between overlapping shear faults are the primary drilling targets and horizontal wells running parallel to the strike of the fault would have the best chances of intercepting good porosity development

tectonic influences on the quaternary drainage evolution on the north western margin of the french central massif the creuse valley example abstract this work examines the links between tectonics and fluvial dynamics on the north western margin of the french central massif geomorphological and sedimentological analyses of detrital deposits were carried out as the basis for correlating the different formations and for reconstructing the palaeodrainage in the creuse basin cross sections of the valleys longitudinal profiles of terraces and glacis indicate post depositional deformation of about 50 m amplitude uplift north and south of gueret and in the eguzon district these deformations are related to the central massif uplift of 50 m above the paris basin since 1 1 ma ois 32 the creuse incision varies from 140 m in the crozant anticline to 60 m in the paris basin an upper pliocene palaeochannel located on the sedelle ardentes issoudun lineament is evidenced by andalusite coming from the fougeres unit the reactivation of the transverse faults between le pin and le menoux has distorted the middle terraces the main knick points are mainly due to tectonics and have been persistent in the landscape since the upper pliocene their recession rate is controlled both by discharge and lithology tributary streams exhibit strong convexities indicating that the erosional response to pliocene uplift has not yet propagated into upland surfaces

processing and quality control strategies for consistent time lapse seismic attributes a case history on an internal blowout using vintage data abstractmany vintage reflection seismic surveys exist that have nonrepeated acquisition geometries or final stacked migrated sections are obtained using different or nonconsistent processing flows this may lead to derived time lapse attributes that are not internally consistent or even conflicting for instance we have focused on a subsurface gas blowout that occurred in 1989 in the norwegian sector of the north sea the 2d site survey data were acquired in 1988 and 1990 and the 3d data were acquired in 1991 and 2005 the various sets of legacy data are plagued by poor repeatability among data acquisitions application of different processing strategies missing prestack data and the presence of multiples all of these factors severely complicate even qualitative interpretation of the gas migration associated with the underground blowout careful time lapse processing may provide useful information even from such challenging legacy data by first computing numerous attributes including instantaneous am

cyclic ground tilt associated with the 2004 2008 eruption of mount st helens 1 the long term behavior of the 2004 2008 effusive eruption of mount st helens was characterized by a gradual decline in the rates of seismicity dome growth and broad scale ground deformation but shallow near periodic drumbeat earthquakes over timescales of minutes indicated episodic short term behavior in part to better characterize this behavior and any associated ground deformation a network of tiltmeters was installed and recorded thousands of cyclic tilt events within the crater the duration of these events from minutes to hours was too long for them to be directly caused by the drumbeat seismicity tilt events were characterized by a recoverable asymmetric pattern of rapid tilt away from the vent followed by a more gradual reversal were highly correlated between different tiltmeters in the crater sometimes occurred in association with volcanic seismicity and ceased at the end of the eruption tilt vectors converged on a point just south of the center of the preexisting 1980s lava dome and the absence of detectable tilt outside the crater suggests a shallow source 1 km we examine several models including cycles of conduit pressurization and plug slip or gas loss and stick slip behavior on the interface between the ascending plug and the 1980s lava dome the small number of stations within the crater prevents a unique determination of source type or geometry but results are consistent with a mechanism involving extrusion of the semisolid dacite plug and or cycles of conduit pressurization

physical modelling of fault scarp degradation under freeze thaw cycles physical modelling has been developed in order to simulate the effects of periglacial erosion processes on the degradation of slopes and scarps data from 41 experimental freeze thaw cycles are presented they attest to the efficiency of periglacial processes that control both erosion and changes in scarp morphology i cryoexpulsion leads to an increase of scarp surface roughness and modifies significantly the internal structure of the active layer ii combined effects of frost creep and gelifluction lead to slow and gradual downslope displacements of the active layer 0 3 cm cycle iii debris flows are associated with the most significant changes in scarp morphology and are responsible for the highest rate of scarp erosion iv quantification of the erosion rate gives values close to 1 cm3 cm 2 for 41 freeze thaw cycles these experimental results are consistent with field data acquired along the la hague fault scarp normandy france where an erosion rate of 4 6 1 m3 m 2 per glacial stage has been computed from the volume of natural slope deposits stored during the weichselian glacial stage these results show that moist periglacial erosion processes could lead to an underestimation of plio quaternary deformation in the mid latitudes copyright 2006 john wiley sons ltd

application of multi seismic attributes analysis in the study of distributary channels abstract during the exploration of stratigraphic reservoirs the key to locating these reservoirs is to identify the sandstone distribution seismic data can be used to recognize large scale distributary channel sedimentary bodies however depiction of sedimentary bodies in small distributary channels using traditional interpretation data from seismic profiles is extremely difficult in the upper cretaceous first sandstone bed of the third member of the nenjiang formation called the nen 3 member for simplicity in the xb area of the southern songliao basin distributary channels are the main sedimentary facies the distributary channels migrate frequently therefore it is difficult to precisely depict the morphology of the channel and the distribution of sandstone in this study we investigated the deposition of distributary channels using equal scale formation plane seismic attributes such as post stack amplitude instantaneous amplitude and seismic waveform classification analyzed well logging data from target formations and mapped the distribution of distributary channels this study shows that seismic sedimentological study and stacking multiple attribute analysis can identify the distribution of distributary channels precisely and effectively the attributes of equal scale strata slices are evidently superior to those of time and horizon slices attribute extraction and selection of equal scale formation slices is an essential step the comprehensive selection of seismic attributes that show a good correlation to a single well can be used to clearly depict channel bodies the overlap of the 40 hz single frequency energy and the rms amplitude depicts the sedimentary characteristics and shapes of sandstone bodies in main channels as well as small scale distributary channels more clearly than a single attribute these attributes show that the first sandstone bed of the nen 3 member was from distributary channels with complex shapes the distributary channels cut across each other vertically and laterally it indicates that during the deposition of the nen 3 member in xb area the direction of the main channel is from north to south and the provenance could be from north and east the method of this paper may provide some helpful suggestions to the geologist using seismic attributes to undertake research on sedimentary environment at other places in the world

slip distribution of the february 27 2010 mw 8 8 maule earthquake central chile from static and high rate gps insar and broadband teleseismic data 1 the shallow depth underthrust earthquake of february 27 2010 mw 8 8 ruptured the subduction plate interface in central chile between 34 s and 38 s we retrieve the spatial and temporal distribution of slip during this mega earthquake through a joint inversion of teleseismic records insar and high rate gps hrgps data additionally our model is shown to agree with broadband surface waves rupture initiated at about 32 km depth and propagated bilaterally resulting in two main slip zones located ssw and nne of the hypocenter nucleation did not take place within or at the edge of one of these main asperities but in between during the first 30s slip propagated predominantly southwards later on the rupture evolved more slowly and more symmetrically eventually the northern asperity became predominant with maximum slip reaching about 20 m most of the seismic moment was released within 110s a relatively short time explained by the bilateral propagation the overall average rupture velocity is 2 6 km s but propagation occurred initially faster towards the south 3 2 km s large slip did not reach the trench a result consistent with the moderate size of the tsunami down dip rupture stopped at about 50 km depth in agreement with the lower limit of the locked zone inferred by ruegg et al 2009 from pre seismic gps data

uplift driven valley incision and river terrace formation in southern england outside the limits of middle pleistocene glaciation the river basins of southern england contain long cenozoic terrestrial sedimentary records of greatest importance are the river terrace sequences which contain biostratigraphical and sedimentary evidence that testifies to the high amplitude climatic changes of the quaternary however trends in valley development cannot easily be accommodated within the framework of quaternary climatic change it is argued in this paper that episodic incision and terrace development result from uplift a consequence of the interplay between continuing alpine orogenic movements and erosion driven isostasy using a simple linear model height age an uplift rate of ca 7 cm ka 1 is estimated for the terrace sequence in the upper thames valley this preliminary model is evaluated using the records of adjacent basins 1997 john wiley sons ltd

active tectonics seismicity and geomorphology with special reference to normandy france integrated studies based on tectonic seismotectonic and geomorphological analyses indicate that normandy northwest france has been an active area during the quaternary topography and landform discontinuities reflect the dislocation and differential uplift of a late cenozoic platform the tectonic activity is represented by i active faults indicated by linear scarps and seismic activity ii offsetting of pre existing surfaces iii plio pleistocene sedimen tation restricted within narrow subsiding zones and iv morphometric properties of drainage basins that indicate zones of differential uplift the inferred strain pattern involves i a shortening direction that strikes nw se as expected in the european context of alpine compression and ii a ne sw trending extension accommodated by nw se normal faults the geomorphological systems encountered in normandy preferentially record differential vertical displacements copy right 2000 john wiley sons ltd

tectonic processes and geomorphological design abstract deep seated geodynamic processes are the cause of the existence of the geotectonic stress field the influence of the latter and therefore of deep seated processes in surface geomorphology is investigated it is noted that the features caused by deep seated geotectonic processes can be distinguished from those caused by exogenic agents weather erosion etc by their statistical characteristics all statistically systematic features are of geotectonic origin random features are of exogenic origin in this paper various types of morphological features are analyzed with regard to their origin it is shown that lineaments seen on air photographs may not be of recent geotectonic origin specific examples of such lineaments being erosion scarps are given next it is shown that the orientation patterns inherent in fluvial and glacial valleys are indeed affected to a large extent by neotectonic processes the same is naturally the case for rift valleys and chains of volcanoes a further interesting subject is presented by the so called tectonic landforms inselbergs cirques the shapes of mountain summits etc are all shown to be directly or indirectly caused by deep seated processes the mass movements on slopes are also of great importance although it is often thought that these are triggered by meteorological conditions it is shown that their basic design is influenced to a large extent by deep seated processes amongst other things this is borne out by a correlation between landslide and earthquake activity finally it is mentioned that the common joints on rock outcrops are also designed by the neotectonic stress field and that the latter can in fact be determined by an analysis of joint orientations in summary it may be stated that although exogenic agents may be responsible for many morphological features deep seated processes have nevertheless a great influence on the fundamental design of such features

pattern recognition of geophysical data abstract a new rock classification method for ground penetrating radar gpr data is presented for cases where no additional geological information is available from boreholes there are non linear relationships between petrophysical properties of rocks and electromagnetic waves which can be handled using two methods derived from statistical learning theory on pattern recognition an investigation was carried out looking at proving the feasibility of the method in principle for use on synthetic models as well as measurement data the different learning methods were also compared the method is based on multivariate statistical learning algorithms for the discrimination of layer boundaries between different rocks the discrimination developed works with artificial neural networks ann and support vector machines svm the processing procedure starts with geological models with varying petrophysical rock parameters which are to be sought in the measurement data the models are used to generate synthetic radargrams from which rock properties can be derived using wave attributes the calculated values of the wave attributes are stored in a multivariate data pool this data pool is used to train the ann and the svm the same wave attributes are derived from the gpr data and also saved in a data pool this generates two data sets for pattern recognition with which to directly classify rock layers wave attributes can therefore be used to derive the non linear correlative relationships between rock properties and gpr data by the weighted matrices of ann and svm the presented method can be used to match reflections in the grr data directly with the layer boundaries of rock formations the classification of a boundary horizon between rock salt and anhydrite is demonstrated on synthetic gpr traces and measurement data from a rock salt mine the advantage of this method is that rock classification is not a priori dependent on borehole data

application of seismic curvature attributes in the delineation of coal texture and deformation in zhengzhuang field southern qinshui basin coal texture refers to the in situ particle size morphological characteristics and structural components of coal beds and it determines the permeability and producibility of a coalbed methane cbm reservoir coal texture is commonly classified into undeformed coal with primary coal texture and deformed coal with increasing degree of deformation including cataclastic coal granulated coal and mylonitized coal geophysical logging has recently been proven effective for detecting coal texture in boreholes but it is inefficient for establishing a regional distribution where there have been only limited amounts of drilling in contrast seismic attributes have high lateral extent and an advantage in terms of characterizing fine structures even minor faults with throws of 2 3 m and other strata deformations by comparing seismic curvature data to the results of 221 core samples from the zhengzhuang field in the southern qinshui basin we provide a seismic curvature attribute based coal texture evaluation method evaluation of the results shows that the coal texture types of the no 3 coal seam include undeformed coal cataclastic coal and some granulated coal the undeformed coal is mainly located in the western and northwestern parts of the study area the cataclastic and granulated coals are mainly distributed in the southern and eastern parts of the study areas the permeability of no 3 coal seam is weakly correlated with undeformed coal and it has a high negative correlation with deformed coal permeability has a strong negative correlation with the maximum curvature attribute of the no 3 coal seam it is suggested that the in situ stress distribution combined with the curvature controlled the local development of the coal texture types and thus resulted in regional differences in permeability finally the distribution characteristics of coal textures of no 3 coal seam in the study area are divided into four types in which the undeformed cataclastic coal dominated area located in the midwestern part of the study area is the most favorable area for cbm production

monitoring viscosity changes from time lapse seismic attenuation case study from a heavy oil reservoir heating heavy oil reservoirs is a common method for reducing the high viscosity of heavy oil and thus increasing the recovery factor monitoring of these viscosity changes in the reservoir is essential for delineating the heated region and controlling production in this study we present an approach for estimating viscosity changes in a heavy oil reservoir the approach consists of three steps measuring seismic wave attenuation between reflections from above and below the reservoir constructing time lapse q and q 1 factor maps and interpreting these maps using kelvin voigt and maxwell viscoelastic models we use a 4d relative spectrum method to measure changes in attenuation the method is tested with synthetic seismic data that are noise free and data with additive gaussian noise to show the robustness and the accuracy of the estimates of the q factor the results of the application of the method to a field data set exhibit alignment of high attenuation zones along the steam injection wells and indicate that temperature dependent viscosity changes in the heavy oil reservoir can be explained by the kelvin voigt model

tilt recorded by a portable broadband seismograph the 2003 eruption of anatahan volcano mariana islands 1 the horizontal components of broadband seismographs are highly sensitive to tilt suggesting that commonly deployed portable broadband seismic sensors may record important tilt information associated with volcanic eruptions we report on a tilt episode that coincides with the first historical eruption of anatahan volcano on may 10 2003 the tilt was recorded by a strekheisen sts 2 seismograph deployed in an underground insulated chamber 7 km west of the active vent an ultra long period signal with a dominant period of several hours was recorded on the e w component beginning at 06 20 gmt on may 10 which coincides with the onset of continuous volcano tectonic vt seismicity and is one hour prior to the eruption time estimated by the volcanic ash advisory center the signal is much smaller on the n s component and absent on the vertical component suggesting it results from tilt that is approximately radial with respect to the active vent an estimate of tilt as a function of time is recovered by deconvolving the record to acceleration and dividing by the acceleration of gravity the record indicates an initial episode of tilt downward away from the volcanic center from 06 20 09 30 gmt which we interpret as inflation of the shallow volcanic source the tilt reverses recording deflation from 09 30 until 17 50 after which the tilt signal becomes insignificant the inflation corresponds to a period of numerous vt events whereas fewer events were recorded during the deflation episode and the vt events subsequently resumed after the end of the deflationary tilt the maximum tilt of 2 microradians can be used to estimate the volume of the source inflation 2 million m3 assuming a simple mogi source model these calculations are consistent with other estimates of source volume if reasonable source depths are assumed examination of broadband records of other eruptions may disclose further previously unrecognized tilt signals

morphotectonic evidence from lateral propagation of an active frontal fold pakuashan anticline foothills of taiwan abstract the pakuashan anticline is uniquely suited for study of the forward and lateral growth of fault related folds the pakuashan ridge development arises from the late quaternary uplift of the most external thrust zone of the western foothills of taiwan from kaoshiung to taichung recent and active westward thrusting occurs at the front of the foothills the pakuashan anticline trending n 150 e in the northern part to n 000 in the southern part has been active throughout the quaternary period this activity is marked by geological structures tectonic geomorphology and seismicity a multisource and multiscale approach to study of the continental collision setting has been undertaken to combine tectonics sedimentology and geomorphology studies of fracture patterns allow identification of two main features of stress orientations a wnw ese compression direction and e w and n s extension directions quantitative geomorphic parameters have been used to define the morphotectonic evolution and to infer tectonic style along the mountain front geomorphic evidence provides significant information on the processes that govern lateral propagation of an active anticline quaternary terraces are uplifted tilted and folded over the pakuashan ridge drainage systems in areas of active compression give information on the thrust zone structures and their development steep drainage and high local relief indicate that the pakuashan anticline forms a well defined zone of high uplift especially in the southern part the two main controls on drainage in that area are rock strength in the hanging wall and propagation of the deformation towards the south

seismic attribute based characterization of coalbed methane reservoirs an example from the fruitland formation san juan basin new mexico the fruitland formation of the san juan basin is the largest producer of coalbed methane in the world production patterns vary from one well to another throughout the basin reflecting factors such as coal thickness and fracture and cleat density in this study we integrated conventional p wave three dimensional 3 d seismic and well data to investigate geological controls on production from a thick continuous coal seam in the lower part of the fruitland formation our objective was to show the potential of using 3 d seismic data to predict coal thickness as well as the distribution and orientation of subtle structures that may be associated with enhanced permeability zones to do this we first derived a seismic attribute based model that predicts coal thickness we then used curvature attributes derived from seismic horizons to detect subtle structural features that might be associated with zones of enhanced permeability production data show that the best producing wells are associated with seismically definable structural features and thick coal although other factors e g completion practices and coal type affect coalbed methane production our results suggest that conventional 3 d seismic data integrated with wire line logs and production data are useful for characterizing coalbed methane reservoirs

post rift compressional reactivation potential of passive margins and extensional basins poly phase deformation of a compressional nature is a common feature in the post rift evolution of passive margins and rifts the compressional mode of deformation in these sedimentary basins originally formed by extension in an intraplate setting is characterized by a spectrum of spatial wavelengths spanning several tens of kilometres up to several hundreds of kilometres the actual mode of compressional deformation appears to be strongly affected by the rheological structure of the underlying lithosphere the level of the regional intraplate stress field and the geometry of the rifted basin configuration prior to late stage compressional reactivation the interplay of plumes and intraplate compressional deformation can lead to temporal transitions from basin inversion to lithospheric folding these modes of deformation lead to substantial differential vertical motions late stage anomalies in subsidence and uplift patterns the development of innovative combinations of numerical and analogue modelling techniques is the key to differentiating different modes of compressional deformation of passive margins and extensional basins the geological society of london 2008

intraplate deformation and 3d rheological structure of the rhine rift system and adjacent areas of the northern alpine foreland the lithosphere of the northern alpine foreland has undergone a polyphase evolution during which interacting stress induced intraplate deformation and upper mantle thermal perturbations controlled folding of the thermally weakened lithosphere in this paper we address relationships among deeper lithospheric processes neotectonics and surface processes in the northern alpine foreland with special emphasis on tectonically induced topography we focus on lithosphere memory and neotectonics paying special attention to the thermo mechanical structure of the rhine graben system and adjacent areas of the northern alpine foreland lithosphere we discuss implications for mechanisms of large scale intraplate deformation and links with surface processes and topography evolution

shear criteria and structural symmetry abstract during the last decade it has been shown that most relevant shear criteria within ductile rocks are asymmetric structures e g pressure shadows shear bands c s structures fabrics tension gashes folds veins the correspondence between coaxial or non coaxial deformation and symmetric or asymmetric particle velocity fields respectively accounts for the use of structural symmetry as an indicator of strain history the application of this symmetry concept to various field examples emphasizes that i the degree of symmetry of a given structural pattern reflects the bulk strain regime irrespective of the size and the mechanical behaviour of the considered system and ii the strain regime can also be inferred from the order of appearance and dominance of structures which contribute to the total deformation pattern even where the progressive deformation results in a complex pattern which cannot be directly interpreted

strainmeters and tiltmeters despite steady effort over the last century continuously recording tiltmeters and strainmeters have not yet been successful except for earth tide measurements this article reviews the techniques and instrument designs that have been developed in this field the continuous measurement of true tectonic motions which have rates of 10 14 s 1 requires extremely high instrument stability but more rapid motions tides and seismic waves apart are even smaller and not much more easily detectable much past effort has been spent improving the transducers used in these instruments which usually measure small displacements the commonest choices are optical the most accurate capacitive the most sensitive and inductive the most rugged nowadays building a transducer is the easiest part a much harder task equally important to a good design is attaching the instrument to the ground so that it can detect the signal wanted this part of the design includes choosing a location a large underground opening is thermally stable but distorting a surface installation is easy to build but noisy because of soil weathering and a borehole is inaccessible to weather but also to the operator all such installations and indeed the whole field of strain and tilt measurement of course rely on the assumption that the deformations of interest can be measured over baselengths of a few hundred meters or less this is true for tides and seismic waves but unproven for tectonic motions appropriate attachment techniques differ for each location and many mundane details such as cementing techniques for borehole instruments remain to be worked out the goal of measuring tectonic and tidal tilt has created many tiltmeter designs most are relatively small instruments that use some form of pendulum or bubble level a few use a liquid surface to measure tilts over a long baseline repeated experience has shown the latter type when well built to be superior to the former proving end monument motions to be a dominant source of noise the same appears to hold true for strainmeters the best results coming from long base laser instruments though strainmeters using rigid or flexible material length standards are useful for special purposes and borehole instruments show promise because achieving a good design has been so difficult it is important to select the goals an instrument must meet and be prepared to compromise on others the difficulty of validating results from this type of instrument makes comparison tests essential such tests as have been made so far show that good results cannot be gotten at low cost or without careful attention to details

lithofacies control on reservoir quality of the viola limestone in southwest kansas and unsupervised machine learning approach of seismic attributes facies classification the hydrocarbon development of the viola limestone in southern kansas usa has encountered challenges regarding the development of a robust data based model of the reservoir quality controls the legacy understanding that hydrocarbon entrapment and reservoir quality are controlled by structure has resulted in less than optimal drilling results in this study an integration of petrographic and geophysical well logs analyses established the main reservoir quality control as dolomitization induced porosity the dolomitization control is supported by comparing best fit trends on density porosity well log values with typical model trends of limestone and dolomite density porosity furthermore this study presents unsupervised artificial neural network ann classification based on five seismic attributes instantaneous frequency energy band width absorption quality factor seismic amplitude that comes in agreement with ca mg ratio and the observed sonic transit time dt log variation with dolomitization porosity increase the hydrocarbon reservoir facies identified by the attributes classification explains the drilling results with high accuracy match to facies class centers and can be used effectively in other settings the integration of multi scale multi data analysis and modeling has provided a solid understanding of the reservoir quality control and distribution this study can be considered as a reliable platform for placing future infill wells in the study area to lower the risk of drilling dry holes