seismogram synthesis for radially layered media using the generalized reflection transmission coefficients method theory and applications to acoustic logging a new method based on generalized reflection and transmission coefficients is proposed to calculate the synthetic seismograms in radially multilayered media this method can be used to efficiently simulate full waveform acoustic logs and crosswell seismic profiles in situations where we need to consider borehole effects the new formulation is tested by comparing our numerical results with previous available work and shows excellent agreement because of the use of the normalized hankel functions and the normalization factors this new algorithm for computing seismograms is stable numerically even for high frequency problems to show the applicability of this new approach to full waveform sonic logging we apply it to investigate the effects of complex invaded zones on the geometrical spreading and attenuation estimation for p waves we find that a damaged zone its velocity is slower than the unperturbed formation velocity exhibits a convergence effect on the p waves and a flushed zone velocity is faster than the unperturbed formation velocity exhibits a divergence effect on the p waves

desert pavement coated surfaces in extreme deserts present the longest lived landforms on earth all exposed rocks on earth s surface experience erosion the fastest rates are documented in rapidly uplifted monsoonal mountain ranges and the slowest occur in extreme cold or warm deserts millennial submeterscale erosion may be approached only in the latter the oldest previously reported exposure ages are from boulders and clasts of resistant lithologies lying at the surface and the slowest reported erosion rates are derived from bedrock outcrops or boulders that erode more slowly than their surroundings thus these oldest reported ages and slowest erosion rates relate to outstanding features in the landscape while the surrounding landscape may erode faster and be younger we present erosion rate and exposure age data from the paran plains a typical environment in the near east where vast abandoned alluvial surfaces 10 2 10 4 km 2 are covered by well developed desert pavements these surfaces may experience erosion rates that are slower than those documented elsewhere on our planet and can retain their original geometry for more than 2 m y major factors that reduce erosion converge in these regions extreme hyperaridity tectonic stability fl at and horizontal surfaces i e no relief and effective surface armoring by a clast mosaic of highly resistant lithology the 10 be concentrations in amalgamated desert pavement chert clasts collected from abandoned alluvial surfaces in the southern negev israel representing the sahara arabia deserts indicate simple exposure ages of 1 5 1 8 ma or correspond to maximum erosion rates of 0 25 0 3 m m y 1 the 36

reconciling tectonic shortening sedimentation and spatial patterns of erosion from 10 be paleo erosion rates in the argentine precordillera abstract the temporal evolution of erosion over million year timescales is key to understand the development of mountain ranges and adjacent fold and thrust belts while models of orogenic wedge dynamics predict an instantaneous response of erosion to pulses of rock uplift stream power based models predict that catchment wide erosion maxima significantly lag behind a pulse of rock uplift here we explore the relationships between rock uplift erosion and sediment deposition in the argentine precordillera fold and thrust belt at 30 s using a combination of 10be derived paleo erosion rates constraints on re exposure using 26al 10be ratios geomorphic observations and detrital zircon provenance we demonstrate that the attainment of maximum upland erosion rates lags the maximum rate of deformation over million year timescales the magnitudes and causes of the erosional delays shed new light on the catchment erosional response to tectonic deformation and rock uplift in orogenic wedges

morphological dating of cumulative reverse fault scarps examples from the gurvan bogd fault system mongolia morphological dating of cumulative reverse fault scarps

tephrochronologic constraints on temporal distribution of large landslides in northwest argentina abstract two morphologic settings in the northwestern argentine prone to giant mountain front collapse deeply incised narrow valleys and steep range fronts bordering broad piedmonts were analyzed through detailed investigations of fossil landslides and related fluvio lacustrine sediments nine different rhyodactic tephra layers were defined by geochemical fingerprinting of glass morphology of pumice stratigraphic relationships and mineralogy the age of three tephra could be determined either directly by 40ar 39ar dating or relatively by 14c dating of associated sediments paranilla ash documentclass aastex usepackage amsbsy usepackage amsfonts usepackage amssymb usepackage bm usepackage mathrsfs usepackage pifont usepackage stmaryrd usepackage textcomp usepackage portland xspace usepackage amsmath amsxtra usepackage ot2 ot1 fontenc newcommand cyr renewcommand rmdefault wncyr renewcommand sfdefault wncyss renewcommand encodingdefault ot2 normalfont selectfont decl

provenance paleo weathering and redox signatures of estuarine sediments from ghana gulf of guinea abstract this paper discriminates the source of sediment supply provenance degree of chemical weathering and redox conditions of holocene sediments cored from the ankobra and pra estuaries of ghana in the gulf of guinea using their geochemical characteristics considerable stratigraphical variations were observed in major element compositions in the sediments from both the ankobra al2o3 5 3 14 2 sio2 75 9 88 2 cao 0 3 1 2 k2o 0 5 1 2 and the pra al2o3 7 8 16 9 sio2 72 8 86 5 cao 0 3 0 4 k2o 0 7 1 2 estuaries elemental compositions were similar in both estuaries depicting similarities in their source rock characteristics some of the major and trace elements correlated significantly r2 0 8 with al2o3 in the pra estuary confirming their possible hydraulic fractionation geochemical classification showed the sediments from both estuaries were predominantly composed of sub arkoses with only a few litharenites the chemical index of alteration cia chemical index of weathering ciw plagioclase index of alteration pia the index of compositional variability icv the sio2 al2o3 ratios and sio2 vs al2o3 k2o nao suggest high degrees of chemical weathering coinciding with warm climatic conditions in the source regions as well as sub matured to mature estuarine sediments deposited under semi arid to semi humid conditions the sediment geochemistry and discrimination diagrams denote similar continental signature derivatives of the sediments from both estuaries both sediments are likely derived from intermediate to felsic granitoid source rocks as well as from a quartzose sedimentary provenance formed in a passive continental margin the ni co and v cr ratios depict sediment deposition under oxic conditions through time in both estuaries

acoustic modes of propagation in the borehole and their relationship to rock properties acoustic waveform measurements in boreholes have important applications in fracture hydrology and radioactive waste disposal but ambiguities in existing interpretation techniques remain a problem we have addressed the problem by using residue theory to predict the relative excitation of various modes contained in experimental waveforms a plane geometry model involving a layer of fluid between two elastic half spaces is shown to provide velocity dispersion curves for propagating modes that are very similar to those for the fluid filled borehole we use the plane geometry model to illustrate the effects of the confined borehole fluid on surface and body waves traveling along the borehole in the elastic solid we also computed excitation functions for some of the lowest order symmetric modes calculated the time domain response of the trapped modes following the shear head waves and compared them to waveforms recorded in boreholes through several homogeneous formations the insight into the mode composit

revealing the pace of river landscape evolution during the quaternary recent developments in numerical dating methods during the last twenty years several technical developments have considerably intensified the use of numerical dating methods for the quaternary the study of fluvial archives has greatly benefited from these enhancements opening new dating horizons for a range of archives at distinct time scales and thereby providing new insights into previously unanswered questions in this contribution we separately present the state of the art of five numerical dating methods that are frequently used in the fluvial context radiocarbon luminescence electron spin resonance esr 230th u and terrestrial cosmogenic nuclides tcn dating we focus on the major recent developments for each technique that are most relevant for new dating applications in diverse fluvial environments and on explaining these for non specialists therefore essential information and precautions about sampling strategies in the field and or laboratory procedures are provided for each method new and important implications for chronological reconstructions of quaternary fluvial landscapes are discussed and where necessary exemplified by key case studies a clear statement of the current technical limitations of these methods is included and forthcoming developments which might possibly open new horizons for dating fluvial archives in the near future are summarised

subsurface characterization of quaternary scarps and their possible connection to main structures of the western margin of precordillera san juan argentina abstract the el tigre fault provides a significant example of pliocene quaternary tectonic activity at the west of precordillera receiving considerable attention in the last years however longitudinal thrusts of the nearest sierra del tigre and a minor piedmont deformation belt identified in its western piedmont are still poorly understood the present work comprised a detailed map of the geomorphological features of tectonic origin and quaternary alluvial fan terraces located between the sierra del tigre and the el tigre fault several topographic and geoelectrical profiles across minor fault and fold scarps were surveyed to define the displacement scarps the geological structure geometries at subsurface and their relationship with main structures geoelectrical models allowed us to recognize three geoelectrical levels a 200 300 m correlated to pleistocene alluvial fan terraces q4 and q3 b ranging from 50 to 300 450 m under level a and correlated to the neogene substratum rodeo formation c

neogene structures overprinting palaeozoic thrust systems in the andean precordillera at 30 s latitude field studies along a 30 s latitude transect of the precordillera in nw argentina indicate that neogene to recent deformation caused high angle faulting that uplifted and breached a palaeozoic east verging thrust stack palaeozoic structures crop out in the higher linear ranges and intramontane neogene basins occur in the intervening valleys the palaeozoic rocks include three tectonic units with contrasting structural styles and differences in stratigraphy the western allochthon includes clastic ordovician rocks metamorphosed to lower greenschist facies and folded by large scale asymmetric east verging folds with a well developed axial planar cleavage this unit overthrusts a siluro devonian flysch type succession of the central imbricate thrust system and associated fault propagation folds in which the thrusts merge into a basal thrust beneath ordovician carbonates middle to upper carboniferous sediments unconformably overlie structures of this imbricate system in the frontal unit minor thrust faults are interpreted to explain the low angle unconformity within palaeozoic rocks neogene deformation causes only a minor overprint of the palaeozoic structure and large scale folding in the frontal unit appears to be mostly of neogene age the new data indicate that neogene intracontinental shortening may be smaller than previously proposed providing new perspectives on the present orogenic architecture along this andean section

a note of caution on the use of boulders for exposure dating of depositional surfaces abstract exposure dating of boulders has been widely applied to determine the age of depositional surfaces under the assumption that the pre depositional nuclide component in most boulders is negligible here we present a case study on fluvial terraces at the active mountain front of the eastern andes where this assumption is clearly invalid because sandstone boulders n 13 from terraces at two sites contain a highly variable inherited 10be component and have apparent 10be ages that exceed the age of the respective surface by up to 90 ka likewise boulders from active stream channels n 5 contain a substantial inherited 10be component equivalent to 5 48 ka of exposure the age of the fluvial terraces is well determined by two approaches that allow to correct for the pre depositional nuclide component 10be dating of amalgamated pebbles and 10be depth profiles on sand samples at site 1 three terraces have 10be ages of 3 5 ka t2 11 13 ka t3 and 16 20 ka t4 which are consistent with the terrace stratigraphy the age of terrace t3 is confirmed by a calibrated 14 c age of 12 61 0 20 ka bp obtained from a wood sample at site 2 terrace t3 has a 10be age of 13 16 ka the average inherited 10be concentration of sand grains determined from depth profiles and stream sediments is small and equivalent to 1 3 ka of exposure in contrast the mean inheritance of pebbles and boulders is higher and equivalent to exposure times of 10 ka and 30 ka respectively these differences in the pre depositional nuclide component are related to the different provenance and transport history of sand pebbles and boulders the sand is derived from rapidly eroding miocene sediments exposed near the mountain front whereas the pebbles and boulders originate from triassic sandstones in the internal part of the fold and thrust belt on their way to the mountain front boulders and pebbles were temporarily stored and irradiated in alluvial fans that are currently reworked as sediment deposition in intramontane basins and their subsequent excavation is common in the andes and other fold and thrust belts the presence of pre depositional nuclide components should be evaluated when applying exposure dating at active mountain fronts

fault growth and landscape development rates in otago new zealand using in situ cosmogenic 10be abstract we use in situ cosmogenic 10 be measurements in quartzites to examine the growth and propagation rates of a late quaternary anticline forming above a blind reverse fault in central otago new zealand we obtain average uplift and propagation rates of 0 10 0 15 mm yr 1 and 1 0 2 0 mm yr 1 respectively over the last 450 000 yr though it is probable that growth occurred episodically with more rapid development in the periods 600 400 kyr and 200 100 kyr and relative quiescence between about 400 and 200 kyr ago these results quantify and confirm a qualitative analysis of the fault evolution based on geomorphology and drainage patterns we obtain minimum 10 be exposure ages of up to 750 000 yr for the quartzites some of the oldest ages obtained by this method outside antarctica which are made possible by the extremely low erosion rates of less than 0 6 mm kyr 1 in the resistant quartzites these rocks consequently provide an opportunity to study geomorphic and tectonic processes in this region over unusually long time periods

calibrated late quaternary age indices using clast rubification and soil development on alluvial surfaces in pilot knob valley mojave desert southeastern california the orange coating varnish that forms on the undersides ventral sides of clasts in desert pavements constitutes a potential relative age indicator using munsell color notation we semiquantified the color of the orange ventral varnish on the undersides of clasts from 15 different alluvial fan and terrace surfaces of various ages ranging from less than 500 to about 25 000 yr all of the surfaces studied are located along the central portion of the left lateral garlock fault in the mojave desert of southern california the amount of left lateral offset may be used to determine the relative ages of the surfaces the previously published slip rate of the fault may also be used to estimate the absolute age of each surface the color of the ventral varnish is strongly correlated with surface age and appears to be a more reliable age indicator than the percentage coverage of dorsal varnish soil development indices also were not as strongly correlated with age as were the colors of the ventral varnish in particular rubification appears to be more useful than soils for distinguishing relative ages among holocene surfaces humidity sensors indicated that the undersides of clasts condensed moisture nightly for a period of several days to over a week after each rain these frequent wet dry cycles may be responsible for the rapid development of clast rubification on holocene surfaces

timing and nature of alluvial fan and strath terrace formation in the eastern precordillera of argentina abstract sixty eight 10 be terrestrial cosmogenic nuclide tcn surface exposure ages are presented to define the timing of alluvial fan and strath terrace formation in the hyper arid san juan region of the argentine precordillera this region is tectonically active and numerous fault scarps traverse quaternary landforms the three study sites marquesado strath complex loma negra alluvial fan and carpinteria strath complex reveal a history of alluvial fan and strath terrace development over the past 225 ka the marquesado complex q3 m surface dates to 17 3 ka whereas the loma negra q1 ln q2 ln q3 ln q4 ln and q5 ln surfaces date to 24 3 ka 48 2 ka 65 13 ka 105 21 ka and 181 29 ka respectively the carpinteria complex comprises eight surfaces that have been dated and include the q1 c 23 3 ka q2 c 5 5 ka q3a c 25 12 ka q3b c 29 15 ka q4 c 61 12 ka q5 c 98 18 ka q6 c 93 18 ka and q7 c 212 37 ka 10 be tcn depth profile data for the loma negra alluvial fan complex and carpinteria strath terrace complex as well as osl ages on some carpinteria deposits aid in refining surface ages for comparison with local and global climate proxies and additionally offer insights into inheritance and erosion rate values for tcns 10 10 4 10 be atoms g of sio 2 and 5 m ma 1 respectively comparison with other alluvial fan studies in the region show that less dynamic and older preserved surfaces occur in the carpinteria and loma negra areas with only younger alluvial fan surfaces preserved both to the north and south these data in combination with that of other studies illustrate broad regional agreement between alluvial fan and strath terrace ages which suggests that climate is the dominant forcing agent in the timing of terrace formation in this region

spatial variations in late quaternary slip rates along the doruneh fault system central iran the doruneh fault system dfs is one of the major active strike slip faults in the arabia eurasia collision zone despite its geological activity no large m 6 5 historical or instrumental earthquakes have been recorded along it to date the rate and distribution of slip as well as the seismic behavior of the dfs have been unknown we reconstructed 67 geomorphic offsets recorded by three successive alluvial abandonment surfaces q1 q2 and q3 displaced along the western wfz and central cfz fault zones the determined ages of 12 36 and 120 ka using in situ produced 10 be and 36 cl cosmogenic nuclides for theses surfaces allowed to estimate three sets of individual left lateral slip rates and consequently to describe the spatiotemporal distribution of slip along the cfz and wfz the slip rates averaged over time intervals of 36 and 120 ka reveal variable slip rates along length but similar slip rates at a point with a maximum rate of 8 2 mm yr during the holocene however the fault slip behavior appears more complex with a maximum rate of 5 3 mm yr the cfz is divided into two 4 km apart segments with symmetrical slip distributions relative to a persistent boundary which has not been ruptured over the last 12 ka the maximum length of seismic fault segments varies from 70 to 100 km which could produce earthquakes with a magnitude of m w 7 2 7 4 this emphasizes the necessity of segmentation models for long strike slip faults that may not necessarily rupture along their whole length during a single earthquake

cosmogenic dating ranging from 20 to 700 ka of a series of alluvial fan surfaces affected by the el tigre fault argentina it is crucial to date continental landforms to quantify processes involved in terrestrial surface evolution especially in regions affected by active tectonics andean quaternary alluvial fan surfaces affected by the el tigre strike slip fault have been studied using combined geomorphic and 10 be exposure age approaches field observations and spot french acronym for satellite for observation of the earth image analysis enable the identification of six alluvial fan units measurements of in situ produced cosmogenic 10 be concentrations in quartzite boulders exposed on the top of fan surfaces show that the depositional periods ended during successive major interglacial stages the calculated minimum exposure ages date the abandonments of the alluvial fan surface from 41 000 8500 yr for the youngest to 670 000 140 000 yr for the oldest unit when linked to the measured maximum cumulative right lateral displacement of stream channels the exposure ages yield a horizontal slip rate of about 1 mm yr on the el tigre fault this study shows that for arid regions where fan surface erosion is minimal in situ produced 10 be can be used to constrain the age of stratigraphically separate alluvial fan surfaces these fan surface exposure ages can be further used to calculate slip rates on active faults and infer depositional periods correlative with climatic events

first tectonic geomorphology study along the longmu gozha co fault system western tibet abstract the longmu gozha co left lateral strike slip fault system lgcf is located in remote western tibet forming a triple junction with both the altyn tagh fault atf and the karakorum fault kf the two major strike slip faults in the region the ashikule gozha co and longmu co faults are clear and distinct left stepping en echelon faults together forming the lgcf system although poorly documented quantifying its activity remains a key problem to understand the kinematics and the tectonic history of the westernmost tibetan plateau indeed the karakax fault nw segment of the atf lgcf and kf together control the tectonics of western tibet which itself controls the extrusion of tibet towards the east with the lgcf acting as a natural boundary for eastward motion of the tibetan plateau due to india s northward impingement the lgcf system shows clear and impressive morphological indications of left lateral active shear that we quantify using field measurements terrestrial lidar along with 10 be surface exposure dating our data suggest a slip rate 9 and 8 mm yr respectively yielding a few mm yr of extension accommodated most likely in the ashikule graben and surroundings located between the atf and karakax faults numerous evidences of recent tectonic related events are present in the vicinity such as the 1951 volcanic eruption as well as the 2008 and 2014 ms 7 3 yutian earthquakes attesting of its high activity in addition the lgcf s en echelon geometry and identical direction with the atf as well as smaller geological offsets and lower slip rate compared to those on the surrounding faults suggest that this segment of the atf may be the most recent

high slip rate for a low seismicity along the palu koro active fault in central sulawesi indonesia accurate chronological records are critical for understanding the landformsevolution and in particular of alluvial fan sequences emplaced during glocal global climatic changes toward this end we measured in situ produced 10be in quartz boulders exposed on top surfaces of sulawesian late quaternary alluvial fans combined geomorphic study spot image and field analyses indicate that this site is composed of twoalluvial fan units in situ produced 10be concentrations suggest that they were emplaced during two successive major climatic events the calculated minimum exposure ages date the younger unit abandonment at 11 000 2 000 years and seem consistent with a late interglacial abandonment age 120 000years for the older unit this study demonstrates that using both the neutron and muon components implicated in the production of in situ10be surficial erosion rates can be estimated 6 m ma in sulawesi and alluvial fan surfaces dated in particular it shows that10be may be used to date fan surface emplacement during the last 120 ka under humid tropical conditions significantly helping to constrain continental paleo climatology in these regions

the geometry of the active strike slip el tigre fault precordillera of san juan central western argentina integrating resistivity surveys with structural and geomorphological data the geometry and related geomorphological features of the right lateral strike slip el tigre fault one of the main morphostructural discontinuities in the central western precordillera of argentina were investigated achievements of this survey include recognition of structural and geometrical discontinuities along the fault trace identification and classification of landforms associated with local transpressional and transtensional sectors observation of significant changes in the fault strike and detection of right and left bends of different wavelength in the central segment of the el tigre fault 2d electrical resistivity tomography surveys were carried out across the fault zone the resistivity imaging permitted to infer the orientation of the main fault surface the presence of blind fault branches along the fault zone tectonic tilting of the quaternary sedimentary cover subsurface structure of pressure ridges and depth to the water table based on this information it is possible to characterize the el tigre fault also as an important hydro geological barrier our survey shows that the main fault surface changes along different segments from a high angle to a subvertical setting whilst the vertical slip component is either reverse or normal depending on the local transpressive or transtensive regime induced by major bends along the trace these local variations are expressed as sections of a few kilometres in length with relatively homogeneous behaviour and frequently separated by oblique or transversal structures

inversion of the shear velocity of the cement in cased borehole through ultrasonic flexural waves abstractyoung s elastic modulus and poisson s ratio of the cement in a cased borehole are important in the prediction of the cement sheath integrity under hydraulic fracturing although these mechanical properties can be derived in principle from the bulk velocities the inversion of these velocities of the cement from the received full waveforms remains a challenging problem especially the s wave velocity we have developed an inversion method based on the round trip traveltimes of the leaked flexural waves ttl to invert the bulk velocities of the medium behind the casing the traveltime difference between the casing wave and the delayed casing wave is the additional time for the leaked wave to travel in the interlayer to the formation and back to the casing to demonstrate the effectiveness of this method synthetic full waveforms with a changing interlayer are calculated when an ultrasonic acoustic beam is incident obliquely on the casing the traveltimes of the wave packets are picked from the enve

distribution of landslides along the andean active orogenic front argentinean precordillera 31 33 s abstract as one of the main environmental effects of earthquakes the distribution of landslides could reflect regional neotectonic activity to that end we carried out an inventory of landslides along the precordillera range 31 33 s comprising the most seismically active region of argentina main quaternary deformation is concentrated in this western central part of the country associated with active faults linked to intense shallow seismic activity

cosmic ray exposure cre dating in a wet tropical domain late quaternary fan emplacements in central sulawesi indonesia accurate chronological records are critical for studying the alluvial fan sequences emplaced during local global climatic changes but in general there are no satisfactory quantitative dating methods available in situ produced be 10 concentrations have been measured in quartz boulders exposed on sulawesian late quaternary fan surfaces these concentrations suggest that the two fan units evidenced by geomorphic study were emplaced during two distinct major climatic events the calculated minimum exposure ages imply abandonment ages of 11 kyr and 120 kyr for the younger and older units respectively this study demonstrates that using both the neutron and muon components implicated in the in situ be 10 production surficial erosion rates can be estimated and alluvial fans dated ln particular it shows that in situ be 10 may be used to date fan emplacement during the last 120 kyr under humid tropical conditions significantly helping to constrain continental palaeoclimatology

seismic hazard reappraisal from combined structural geology geomorphology and cosmic ray exposure dating analyses the eastern precordillera thrust system nw argentina because earthquakes on large active thrust or reverse faults are not always accompanied with surface rupture paleoseismological estimation of their associated seismic hazard is a difficult task to improve the seismic hazard assessments in the andean foreland of western argentina san juan province this paper proposes a novel approach that combines structural geology geomorphology and exposure age dating the eastern precordillera of san juan is probably one of the most active zones of thrust tectonics in the world we concentrated on one major regional active reverse structure the 145 km long villic um pedernal thrust where this methodology allows one to 1 constrain the quaternary stress regime by inversion of geologically determined slip vectors on minor or major fault planes 2 analyse the geometry and the geomorphic characteristics of the villic um pedernal thrust and 3 estimate uplift and shortening rates through determination of in situ produced 1 0 be cosmic ray exposure cre ages of abandoned and uplifted alluvial terraces from a structural point of view the villic um pedernal thrust can be subdivided into three thrust portions constituting major structural segments separated by oblique n40 e trending fault branches along the three segments inversion of fault slip data shows that the development of the eastern precordillera between 31 s and 32 s latitude is dominated by a pure compressive reverse faulting stress regime characterized by a n110 10 e trending compressional stress axis 1 a geomorphic study realized along the 18 km long las tapias fault segment combined with cre ages shows that the minimum shortening rate calculated over the previous 20 kyr is at least of the order of 1 mm yr 1 an earthquake moment tensor sum has also been used to calculate a regional shortening rate caused by seismic deformation this analysis of the focal solutions available for the last 23 yr shows that the seismic contribution may be three times greater than the shortening rate we determined for the las tapias fault i e 3 mm yr 1 suggesting that the san juan region may have experienced a seismic crisis during the 20th century moreover the ramp that controls the development of the eastern precordillera appears to be one of the main seismic sources in the san juan area particularly the 65 km long villic um las tapias segment a first order evaluation of the seismic hazard parameters shows that this thrust segment can produce a maximum earthquake characterized by a moment magnitude of 7 3 0 1 and a recurrence interval of 2 4 1 5 kyr this part of the villic um pedernal ramp may have ruptured during the ms 7 4 1944 san juan earthquake producing very few surface ruptures and only distributed flexural slip deformation on to the neogene foreland bedding planes between the eastern precordillera and pie de palo