holocene fault scarps near tacoma washington usa airborne laser mapping confirms that holocene active faults traverse the puget sound metropolitan area northwestern continental united states the mapping which detects forest floor relief of as little as 15 cm reveals scarps along geophysical lineaments that separate areas of holocene uplift and subsidence along one such line of scarps we found that a fault warped the ground surface between a d 770 and 1160 this reverse fault which projects through tacoma washington bounds the southern and western sides of the seattle uplift the northern flank of the seattle uplift is bounded by a reverse fault beneath seattle that broke in a d 900 930 observations of tectonic scarps along the tacoma fault demonstrate that active faulting with associated surface rupture and ground motions pose a significant hazard in the puget sound region

lidar and 2d electrical resistivity tomography as a supplement of geomorphological investigations in urban areas a case study from the city of wroclaw sw poland in urbanized areas particularly in lowland terrains and floors of large river valleys the natural land configuration is often hard to recognize due to a long history of human activity accordingly archaeological works in cities which supply knowledge on settlement conditions are usually accompanied by geological and geomophological research lately data from light detection and ranging lidar have become a valuable source of information on urban land configuration geophysical methods are also becoming increasingly popular in background studies the paper presents a method of using and linking these sources of spatial information about landforms in such areas the main aim is to identify to what extent these complementary sources of data and the proposed method can be used in such a specific environment to reconstruct natural buried terrain morphology the city of wroclaw in central europe serves as an example to this end geomorphometric studies were conducted with the use of digital elevation models dems based on lidar scanning and derivated land surface parameters saga wetness index channel network base level and altitude above channel network the study also involved determining morphological edges and measurements of the meanders of the odra as well as expanding information on the spatial distribution of alluvia and the structure of slope breaks to this end geophysical measurements were conducted using the two dimensional electrical resistivity tomography method additionally five typical sequences of man made ground present within the perimeter of the city were distinguished as a result a map of the main landforms of wroclaw is presented finally we argue that although high resolution dem and derivate land surface parameters are very useful in terrain analysis places with thick man made ground or strongly levelled areas must be recognized by geoarchaeological excavations or geological bore holes the geophysical survey is useful to identify buried morphological edges and older relief elements in open areas

late devonian early carboniferous volcanism in western cape breton island nova scotia the fisset brook formation of western cape breton island and its equivalents at macmillan mountain and the north baddeck river are examples of late devonian and early carboniferous volcanic sequences associated with the formation of post acadian successor basins in the northeastern appalachians they consist of bimodal basalt rhyolite suites interbedded with alluvial fan lacustrine and rare fluvial sediments the earliest volcanic products are rhyolites and somewhat evolved basalts associated with coarse sediments followed by tholeiitic to transitional basalt flows interlayered with lacustrine type deposits geochemical studies on the fisset brook formation indicate extensive remobilization of alkalies ca rb and sr making these elements inappropriate for determining tectonic setting or magmatic affinity use of less mobile elements ti nb y and zr suggests that the basalts are tholeiitic and that the apparent alkalinity of the type section lavas is a result of alteration we conclude that volca

landslide recognition and mapping in a mixed forest environment from airborne lidar data abstract a precise accurate and complete landslide inventory is indispensable for the establishment of reliable landslide susceptibility and hazard maps in the preparation of landslide inventories dense vegetation cover is the major obstacle that confounds the topographic signature of landslides today the growing usage of light detection and ranging lidar technology in the field of geoscience illuminates the mystery of the landscapes cloaked in dense vegetation by providing a new visual acuity to researchers turkey similar to many mid latitude mountainous countries suffering from landslides is still continuing landslide inventory mapping with conventional methods such as aerial photo interpretations api although 68 of landslide events occurred under dense forest cover in the north of the country despite the country wide medium scaled landslide catalogs the number and the abundance of landslides covered by forests remain largely unknown regardless of the increasing availability of high resolution remote sensing data from these motivating insights and drawbacks the study s focus is to evaluate the capability of mapping landslides by visually analyzing airborne lidar dtm derivatives and compare the results with the 1 25 000 scaled api based inventory to understand the potential contribution of lidar technology in europe s deadliest country turkey in terms of landslides the landslide mapping results for a test area located in the densely forested ulus basin western black sea region reveal that the extent and the number of the mapped landslides n 902 from the airborne lidar data are much higher than those of the available api based landslide inventory which includes 67 landslides comparative analysis on topographic signatures of landslides is also underpinned on a distinct discrepancy of slope failure diagnostic indicators captured by the two available dems derived from lidar and 1 25 000 scaled topographic maps emphasizing the success rate of lidar derived dem in recognition and mapping landslides with higher precision and accuracy together with all analysis results the landslide recognizability degree assessment based on the forest cover percentage and slope height differences of landslides highlights that the lidar data enable landslides to be defined up to 100 m2 while this value is 20 times lower than that of estimated values from api based landslides in addition to underlining the contribution of lidar technology to the recognition of landslides hidden under dense vegetation these findings stress the importance of lidar data on complete and accurate landslide inventories for production of reliable susceptibility and hazard maps and further a better understanding of the landslide processes and reducing related losses

changes in failure stress and stress transfer during the 1976 77 friuli earthquake sequence summary coulomb stress changes related to the sequence of strong earthquakes that affected the friuli area northeastern italy during the period 1976 77 have been investigated to explore the possibility of fault interaction and stress transfer mechanisms the seismic sequence that followed the mw 6 4 mainshock of 1976 may 6 consists of 5 events of mw between 5 2 and 6 0 during the same year and one event of mw 5 3 that occurred in 1977 september all characterized by thrust focal mechanisms the area is affected by a regional compressive stress which tends to activate n dipping thrust planes the goal of this study is to analyse and verify the relationship between the stress changes induced by the mainshock and the occurrence of subsequent events our results show that the mainshock induced a variation in the stress field in the area where most of the seismic events occurred our modelling shows a positive correlation between the areas of increased coulomb stress induced by the mainshock and the distribution of seismicity that followed this evidence suggests stress interaction and the possibility that the mainshock promoted the rupture of those faults associated with the event of 1976 may 9 mw 5 1 and the events of 1976 september 11 mw 5 2 and 5 6 1976 september 15 mw 6 0 and 1977 september 16 mw 5 3 the coulomb stress caused by co seismic dislocations decreased in the zone where an mw 5 9 earthquake occurred on september 15 at 03 15 when we included the contribution of the regional tectonic loading in the calculation of coulomb stress changes we found a positive correlation between the hypocentral area of the september 15 03 15 event and the area of coulomb stress increase aftershocks that occurred after the mainshock but before the september 15 03 15 event are also located in the area of coulomb stress increase

tectonic stacking of metamorphic zones in cheticamp river area cape breton highlands nova scotia metabasic and quartzo feldspathic schists and gneisses of the cheticamp river area can be subdivided into three north south trending metamorphic belts the westernmost belt the low grade belt has been metamorphosed to transitional greenschist amphibolite facies with development of one penetrative foliation the central medium grade belt has been metamorphosed to amphibolite facies with development of two penetrative foliations the eastern high grade belt has been metamorphosed to amphibolite facies accompanied by development of strong gneissic segregation and nonanatectic migmatite leucosomes during formation of two penetrative foliations deformation has been inhomogeneous in each of these belts most rocks in each belt show evidence of post tectonic porphyroblast growth however deformation continued after the metamorphic peak in localized zones very high strain occurred in many of these zones during and after the metamorphic peak so that early formed fold axes were rotated towards the stretching d

identification of a suspected quaternary fault in eastern korea proposal for a paleoseismic research procedure for the mapping of active faults in korea abstract in terms of seismic hazard in the korean peninsula the occurrence of destructive earthquakes has long been overlooked because of no serious modern instrumental seismicity and lack of historical earthquake records of large earthquakes in recent years although the importance and uses of paleoseismological studies has significantly increased in seismic hazard assessments of critical facilities there is still a huge lack of paleoseismological data to improve our knowledge for korean active tectonics and relevant seismic hazards in this study we identified and characterized a suspected quaternary fault in the eastern part of the korea peninsula based on lineament analyses field observations and trench surveys we focus on a prominent lineament around the northern part of the previously reported but not sufficiently studied maeup fault firstly a potential fault lineament is recognized by geomorphic expressions in a mountainous area from satellite and digital elevation model dem generated images then fault related geomorphic and hydrologic features such as disconnected drainages sag ponds and asymmetric water leaking out on an artificial ditch were observed along the lineament in the field studies finally the existence of the fault is confirmed by an exposure of a 2 5 m wide fault core in trench surveys the internal structures of the fault core i e slip surfaces slickenlines and s c fabrics indicate that the fault evolved via a series of slip events under a variety of tectonic settings probably leading up to the current stress regime sustained during quaternary thus our results suggest that the newly identified fault could be a quaternary fault and hence it is necessary to perform more paleoseismic investigations around the study region this case study emphasizes the importance of the careful interpretation of tectonic landforms and fault zone structures in the study of active faults and proposes a suitable research procedure for the identification of active faults in korea

determining the present day kinematics of the idrija fault slovenia from airborne lidar topography abstract located in central europe at the junction of the southern alps and the dinarides the 100 km long idrija fault striking n310 and dipping 80 ne is often considered as the potential source of the historical 1511 earthquake estimated macroseismic magnitude mm 6 8 using 1 25 000 to 1 5000 topographical maps satellite images spot5 12 5 m illuminated dem and airborne lidar data derived 1 m dem we examined in detail the idrija fault trace along a 20 km long swath in the central portion of the fault combining topographic and remote sensing data allows characterizing the recent activity along the idrija fault and estimating its cumulative displacement along strike between tolmin and godovic the fault trace is mostly linear but appears divided into three disconnected segments of 11 20 km long morphological evidences such as offset streams and ridges and major drainage abandonments suggest ongoing movement at three sites field observations and lidar dem analysis allow measuring cumulative dextral offsets comprised between 35 and 65 m we found two larger offsets of 140 m and 360 m at the southeasternmost site the vertical component is significant and revealed by a rake ranging from 0 to 33 the derived n303 n310 striking slip vector is in agreement with the motion along this fault as suggested by the geodesy assuming that the smallest measured offsets have been recorded after the last glacial maximum lgm about 20 ka ago the minimum slip rate for the idrija fault is about 1 5 mm yr over this period of time

importance of seasonal and annual layers in controlling backscatter to radar altimeters across the percolation zone of an ice sheet radar altimeters are one of the main tools for measuring elevation changes across the antarctic and greenland ice sheets and larger ice caps a ground based radar was deployed in autumn 2004 and spring 2006 in the percolation zone of the greenland ice sheet this radar is a high bandwidth system operating in the ku band the same frequency as several satellite altimeters measurements were made over an elevation range of 1795 to 2350 m along with snow pit and shallow core studies these measurements demonstrate the spatial and temporal variations in the backscatter relative strengths of surface and volume reflections change dramatically between spring and autumn and there is also high spatial variability across the percolation zone the extent of percolation will affect elevation estimates made by radar altimeters

morphologic dating of fault scarps using airborne laser swath mapping alsm data 1 models of fault scarp morphology have been previously used to infer the relative age of different fault scarps in a fault zone using labor intensive ground surveying we present a method for automatically extracting scarp morphologic ages within high resolution digital topography scarp degradation is modeled as a diffusive mass transport process in the across scarp direction the second derivative of the modeled degraded fault scarp was normalized to yield the best fitting in a least squared sense scarp height at each point and the signal to noise ratio identified those areas containing scarp like topography we applied this method to three areas along the san andreas fault and found correspondence between the mapped geometry of the fault and that extracted by our analysis this suggests that the spatial distribution of scarp ages may be revealed by such an analysis allowing the recent temporal development of a fault zone to be imaged along its length

long term seismic behavior of a fault involved in a multiple fault rupture insights from tectonic geomorphology along the neodani fault central japan abstract multiple faults with different paleoseismic histories sometimes rupture simultaneously resulting in a larger earthquake than expected to test behavioral models for a fault involved in a multiple fault rupture we performed detailed tectonic geomorphological mapping along the neodani fault central japan one of several faults that ruptured simultaneously during the devastating 1891 m w 7 5 nobi earthquake our mapping showed that the along strike distributions of the long term rates of left lateral and vertical slips generally mimic in shape those of the 1891 slip implying that the slip patch behavior in which smaller more frequent earthquake ruptures fill in low slip portions of the 1891 rupture does not apply to the neodani fault if the earthquake recurrence interval estimated from a previous paleoseismic trench is correct however the neodani fault should not be characterized by repetition of same slip function earthquake ruptures or the characteristic slip function behavior the observations can instead be explained by the semicharacteristic slip function behavior in which a similarly shaped slip distribution is repeated independently of the rupture of adjacent faults but the amount of slip varies nonetheless characteristic slip function behavior may still be a valid interpretation if some of the paleoseismic events identified in the trench are minor sympathetic slip events although we found that the shape of the slip distribution has been quite stable through successive earthquakes including a multiple fault rupture earthquake further paleoseismic efforts are warranted to examine the stability in the amount of slip

river gradient anomalies reveal recent tectonic movements when assuming an exponential gradient decrease along a river course abstract high resolution digital models combined with gis or other terrain modelling software allow many new possibilities in geoscience in this paper we develop describe and test a novel method the gla method to detect active tectonic uplift or subsidence along river courses it is a modification of hack s sl index method in order to overcome the disadvantages of the latter the core assumption of the gla method is that over geological time river profiles quickly adjust to follow an exponential decrease in elevation along the river course any large deviation can be attributed to active tectonic movement or to disturbances in erosion sedimentation processes caused by an anthropogenic structure e g artificial dam during the testing phase the locations of identified deviations were compared to the locations of faults identified on a 1 100 000 geological map results show that higher magnitude deviations are found within a maximum radius of 200 m from the fault and the majority of detected deviations within a maximum radius of 600 m from faults or thrusts however these results are not the best that could be obtained because the geological map that was used and the only one available for the area is not of the appropriate scale and was therefore not precise enough comparison of deviation magnitudes against psinsar measurements of vertical displacements in the vicinity revealed that in spite of the very few suitable points available a good correlation between both independent methods was obtained r 2 0 68 for the e research area and r 2 0 69 for the w research area the gla method was applied to the three test sites where previous studies have shown active tectonic movements it shows that deviations occur at the intersections between active faults and river courses as well as also correctly detected active uplift attributed to the increased sedimentation rate above an artificial hydropower dam and an increased erosion rate below the method gives promising results and it is acknowledged that the gla method needs to be tested in other locations around the world

subsidence in late paleozoic basins in the northern appalachians during the interval between continental collision in the devonian and continental breakup in the triassic the northern appalachians became the site of a wide plate boundary zone of dominantly right lateral strike slip as is typical of intracontinental transforms tectonism was both diachronous and rapidly variable along strike through regimes of pure strike slip transpressional deformation and rapid subsidence of extensional basins up to 9 km of mainly nonmarine clastic sediments accumulated in these local depocenters which subsided episodically in two stages 1 an initial phase of stretching and thinning of the lithosphere when subsidence was rapid fault controlled and often accompanied by volcanism and 2 a subsequent phase of gradual thermal subsidence during which the depositional basins expanded to bury the earlier border faults and progressively younger sedimentary units onlapped basement the largest depocenter the magdalen basin opened as a pull apart between strike slip faults in newfoundland and new brunswick from late devonian to early carboniferous subsequent thermal subsidence affected a large area during medial and late carboniferous a phenomenon that is well recorded to the north and west where no later tectonism occurred in areas to the south and east of the basin strike slip on other faults continued into the time of thermal subsidence introducing complications such as localized transpressional deformation and rapid subsidence in smaller pull aparts

the role of landslides in downslope transport of caprock derived boulders in sedimentary tablelands stolowe mts sw poland abstract escarpment slopes in sedimentary tablelands are often mantled by extensive boulder blankets while lithology shows beyond doubt that caprock is the source of boulders the processes involved in boulder movement and their distribution patterns are rarely examined in this paper we investigate the role of landslides initiated within middle and lower escarpment slopes in redistributing boulder covers on the example of the stolowe mountains in sw poland quartz sandstones form caprock and give rise to precipitous albeit rather low 30 m high at most typically 10 15 m uppermost slope sections and are the source of boulders which occur at distances even 1 km away from the caprock on the nearly flat footslope sedimentary series beneath caprock include fine grained rocks such as mudstones claystone and calcareous sandstones geomorphological mapping and geomorphometric analysis of a high resolution dem allowed us to identify landform patterns interpreted as resulting from landslides both rotational and translational the latter produced distinctive tread and riser topography with risers up to 10 m high results of geophysical prospecting using electrical resistivity tomography ert confirm the presence of allochthonous sandstone derived upper layer that wedges out downslope and indicate resistivity contrasts at depth of 5 15 m interpreted as basal boundaries of landslide material sandstone boulders rafted on top of slid masses and reached very distant footslope settings the primary role of landsliding consists of transporting allochthonous boulders further than would be possible otherwise and accumulating boulders in clusters and linear belts across the slope notably on risers

pathways of geomorphic evolution of sandstone escarpments in the gory stolowe tableland sw poland insights from lidar based high resolution dem abstract the tableland of the stolowe mountains sw poland with its prominent mesas and sandstone capped escarpments belongs to the most spectacular geomorphic landscapes of central europe while the gross morphological features of the area have long been recognized the evolutionary pathways of densely forested and poorly accessible escarpment slopes remained poorly understood in this paper we use lidar data to shed a new light on landform inventories within the escarpments their spatial patterns and using process from form reasoning on the longer term evolution of the escarpments four sites two on each major escarpment have been subject to detailed analysis which involved examination of shaded relief slope plan and profile curvature and topographic wetness index in each case the 1 1 m model was used while for the most complex site at mt szczeliniec wielki the results were compared with the 5 5 m model to check the impact of model resolution on geomorphic interpretation despite some loss of information involved in model re interpolation to the coarser scale the main features of escarpment morphology could still be recognized on the other hand automatic landform classification based on the calculation of topographic position index from the 10 10 m model and performed for the entire tableland failed to reveal differences between various sections of the escarpments detectable on finer models the analysis of spatial patterns of minor landforms within the escarpments identified on lidar derived models shows that no single pathway of escarpment evolution exists both the upper slopes in sandstone caprock and the mid slopes in weaker rocks show signs of instability and these are not necessarily coupled large scale caprock failures do occur but seem rare and localized sandstone free faces are rather subject to continuous slow retreat by detachment of individual joint bound blocks another zone of instability occurs well below the caprock and the dominant processes are shallow landslips initiated within weak deformable rocks

digital landscapes of deglaciation identifying late quaternary glacial lake outburst floods using lidar high resolution dems obtained from lidar topographic data have led to improved landform inventories e g landslides and fault scarps and understanding of geomorphic event frequency here we use airborne lidar mapping to investigate meltwater pathways associated with the tweed valley palaeo ice stream uk in particular we focus on a gorge downstream of palaeolake milfield previously mapped as a sub glacial meltwater channel where the identification of abandoned headcut channels run up bars rock cut terrace surfaces and eddy flow features attest to formation by a sub aerial glacial lake outburst flood glof caused by breaching of a sediment dam likely an esker ridge mapping of these landforms combined with analysis of the gorge rim elevations and cross section variability revealed a two phase event with another breach site downstream following flow blockage by higher elevation drumlin topography we estimate the magnitude of peak flow to be 1 3 103 m3 s duration of the event to range from 16 155 days and a specific sediment yield of 107 109 m3 km2 yr we identified other outburst pathways in the lower tweed basin that help delineate an ice margin position of the retreating tweed valley ice stream the results suggest that low magnitude outburst floods are under represented in quaternary geomorphological maps we therefore recommend regional lidar mapping of meltwater pathways to identify other glofs in order to better quantify the pattern of freshwater and sediment fluxes from melting ice sheets to oceans despite the relatively low magnitude of the till outburst event it had a significant impact on the landscape development of the lower tweed valley through the creation of a new tributary pathway and triggering of rapid knickpoint retreat encouraging new regional models of post glacial fluvial landscape response copyright 2015 john wiley sons ltd

the cheticamp pluton a cambrian granodioritic intrusion in the western cape breton highlands nova scotia the cheticamp pluton consists of biotite granodiorite locally megacrystic in the north and museovite biotite granodiorite in the south in probable faulted contact these two rock types especially the biotite granodiorite show a broad range in modal and chemical compositions they are interpreted to be cogenetic with the museovite biotite grandiorite derived from the biotite granodiorite by crystal fractionation involving mafic minerals plagioclase and sphene the overall peraluminous composition of the suite resulted from the fractionation process probably enhanced by alteration rather than from derivation from peraluminous source rocks a seven point whole rock rb sr isochron indicates an age of 525 40 ma the pluton intruded dioritic rocks and quartzo feldspathic gneisses thus indicating precambrian ages for these units it probably also postdates the western highlands volcanic sedimentary complex a major undated stratigraphic unit in the cape breton highlands although the age overlaps t

use of small unmanned aerial vehicle suav acquired topography for identifying and characterizing active normal faults along the seerteng shan north china abstract high resolution topographic datasets are being increasingly applied in studies of active tectonics for precise quantification of lateral and vertical offsets of landforms digital elevation models dem acquired by airborne light detection and ranging lidar have also been used for morphological analysis of tectonic scarps to infer the seismic slip history of active faults however the high cost of conducting lidar studies limits its widespread application in contrast the potential applicability of the low cost and portable small unmanned aerial vehicles suav combined with structure from motion sfm techniques to investigate morphological features of fault generated scarps and their paleoseismic implications has not been fully explored here based on suav acquired dems and field observations we present a case study of the morphological features of fault scarps along the seertengshan piedmont fault spf a major boundary fault of the hetao graben north china and discuss their paleoseismic implications the results demonstrate that low angle 2000 years ago the observed 1 8 2 5 m high fault scarps with single slope sections probably represent the most recent incremental displacements associated with surface rupturing earthquake s topographic data acquired by suav are suitable for quantitative morphological analyses of fault generated scarps in actively deforming regions and can contribute to assessments of seismic hazard

near field deformation from the el mayor cucapah earthquake revealed by differential lidar large moment magnitude m w 7 continental earthquakes often generate complex multifault ruptures linked by enigmatic zones of distributed deformation here we report the collection and results of a high resolution nine returns per square meter airborne light detection and ranging lidar topographic survey of the 2010 m w 7 2 el mayor cucapah earthquake that produced a 120 kilometer long multifault rupture through northernmost baja california mexico this differential lidar survey completely captures an earthquake surface rupture in a sparsely vegetated region with pre earthquake lower resolution 5 meter pixel lidar data the postevent survey reveals numerous surface ruptures including previously undocumented blind faults within thick sediments of the colorado river delta differential elevation changes show distributed kilometer scale bending strains as large as 10 3 microstrains in response to slip along discontinuous faults cutting crystalline bedrock of the sierra cucapah

fault slip and earthquake recurrence along strike slip faults contributions of high resolution geomorphic data article i nfo understanding earthquake eq recurrence relies on information about the timing and size of past eq ruptures along a given fault knowledge of a fault s rupture history provides valuable information on its potential future behavior enabling seismic hazard estimates and loss mitigation stratigraphic and geomorphic evidence of faulting is used to constrain the recurrence of surface rupturing eqs analysis of the latter data sets culminated during the mid 1980s in the formulation of now classical eq recurrence models now routinely used to assess seismic hazard within the last decade light detection and ranging lidar surveying technology and other high resolution data sets became increasingly available to tectono geomorphic studies promising to contribute to better informed models of eq recurrence and slip accumulation patterns after reviewing motivation and background we outline requirements to successfully reconstruct a fault s offset accumulation pattern from geomorphic evidence we address sources of uncertainty affecting offset measure ment and advocate approaches to minimize them a number of recent studies focus on single eq slip distribu tions and along fault slip accumulation patterns we put them in context with paleoseismic studies along the respective faults by comparing coefficients of variation cv for eq inter event time and slip per event and find that a single event offsets vary over a wide range of length scales and the sources for offset variability differ with length scale b at fault segment length scales single event offsets are essentially constant c along fault offset accumulation as resolved in the geomorphic record is dominated by essentially same size large offset in crements and d there is generally no one to one correlation between the offset accumulation pattern constrained in the geomorphic record and eq occurrence as identified in the stratigraphic record revealing the higher resolution and preservation potential of the latter while slip accumulation along a fault segment may be dominated by repetition of large nearly constant offset increments timing of surface rupture is less regular

detailed mapping and rupture implications of the 1 km releasing bend in the rodgers creek fault at santa rosa northern california airborne light detection and ranging lidar topography reveals for the first time the trace of the rodgers creek fault rcf through the center of santa rosa the largest city in the northern san francisco bay area vertical deformation of the santa rosa creek floodplain expresses a composite pull apart basin beneath the urban cover that is part of a broader 1 km wide right releasing bend in the fault high resolution geophysical data illuminate subsurface conditions that may be responsible for the complex pattern of surface faulting as well as for the distribution of seismicity and possibly for creep behavior we identify a dense magnetic basement body bounded by the rcf beneath santa rosa that we interpret as a strong asperity likely part of a larger locked patch of the fault to the south a local increase in frictional resistance associated with the basement body appears to explain 1 distributed fault normal extension above where the rcf intersects the body 2 earthquake activity around the northern end of the body notably the 1969 m l 5 6 and 5 7 events and aftershocks and 3 creep rates on the rcf that are higher to the north of santa rosa than to the south there is a significant probability of a major earthquake on the rcf in the coming decades and earthquakes associated with the proposed asperity have the potential to release seismic energy into the cotati basin beneath santa rosa already known from damaging historical earthquakes to produce amplified ground shaking

airborne laser swath mapping of the summit of erebus volcano antarctica applications to geological mapping of a volcano abstract the lidar observations reported here have provided the first high precision topographic data on the active craters of erebus volcano antarctica digital elevation data are invaluable for geomorphic analysis of volcanoes especially when combined with methods to automatically extract landscape features the data are indispensable for studying eruptive events and volcano tectonic processes airborne laser scanning or lidar is a rapidly emerging technology to map surface topography with high accuracy and detail comparable to a 1 1000 scale map in the austral summer of 2001 2002 airborne laser scanning data were collected in antarctica over the summit plateau of erebus volcano we describe the high resolution data set from erebus products derived from the data and demonstrate how extracted topographic features can be used in the geomorphic analysis of volcanoes background is presented on the airborne laser scanning method and on the accuracy estimation of laser points we describe the computation of a high resolution dem with a grid size of 2 m 2 m for the summit area of erebus volcano errors in the dem are assessed using independent ground based gps data and the rms error is estimated to be 0 39 m visualization methods reveal topographic features that are very useful for geomorphic analysis automatic feature extraction and processing is necessary to exploit the high resolution and accurate elevation data methods are described to extract 1d and 2d features and organize them for subsequent analysis fitting analytical functions to 3d point clouds or dems is particularly effective in extracting topographic features including planes higher order surfaces cones and conic sections these methods are used to obtain a quantitative description of the calderas and modern day crater of erebus especially valuable are the measured surface areas if the lava lakes as these control thermal emissions and gas fluxes from the volcano examination of the surface elevations of ray lava lake werner vent and active vent indicates that the active vents were more or less in magmastatic equilibrium in 2001 december conic segments are fitted to mapped sections of caldera rims to identify the sections buried under younger lava flows or covered by ice and snow automatic methods are used to detect and characterize lava channels using geomorphometric maps generated from the dem

developing sub 5 m lidar dems for forested sections of the alpine and hope faults south island new zealand implications for structural interpretations abstract kilometre wide airborne light detection and ranging lidar surveys were collected along portions of the alpine and hope faults in new zealand to assess the potential for generating sub 5 m bare earth digital elevation models dems from ground return data in areas of dense rainforest bush cover as an aid to mapping these faults the 34 km long franz whataroa lidar survey was flown along the densely vegetated central most portion of the transpressive alpine fault six closely spaced flight lines 200 m apart yielded survey coverage with double overlap of swath collection which was considered necessary due to the low density of ground returns 0 16 m 2 or a point every 6 m2 under mature west coast podocarp broadleaf rainforest this average point spacing 2 5 m allowed for the generation of a robust high quality 3 m bare earth dem the dem confirmed the zigzagged form of the surface trace of the alpine fault in this area originally recognised by norris and cooper 1995 norris and cooper 1997 and highlights that the surface strike variations are more variant than previously mapped the 29 km long hurunui hope lidar survey was flown east of the main divide of the southern alps along the dextral slip hope fault where the terrain is characterised by lower rainfall and more open beech forest flight line spacings of 275 m were used to generate a dem from the ground return data the average ground return values under beech forest were 0 27 m 2 and yielded an estimated cell size suitable for a 2 m dem in both cases the lidar revealed unprecedented views of the surface geomorphology of these active faults lessons learned from our survey methodologies can be employed to plan cost effective high gain airborne surveys to yield bare earth dems underneath vegetated terrain and multi storeyed canopies from densely forested environments across new zealand and worldwide

are strongly peraluminous magmas derived from pelitic sedimentary sources igneous compositions that require the presence of a phase more aluminous than biotite are here designated as strongly peraluminous ps such compositions are common but subordinate in felsic rocks and exceedingly rare in more mafic rocks the term s type has been applied to many igneous rocks based largely or even solely upon their ps compositions neglecting or placing less emphasis on other criteria for sedimentary parentage in chappell and white s i and s type classification system the s type designation was in fact initially restricted to granites which were thought to have been derived from a chemically mature strongly weathered pelitic shaly source application of chappell s and white s criteria together with others based upon isotopic and phase equilibria considerations leads to the following conclusions about ps igneous rocks worldwide 1 very few ps rocks are derived entirely from pelitic sources 2 a majority are derived largely from intermediate to felsic crustal sources including

escarpment retreat in sedimentary tablelands and cuesta landscapes landforms mechanisms and patterns abstract although the general concept that escarpments in layered rocks retreat through time was offered more than 150 years ago recognizing the exact mechanisms patterns and rates of retreat remains a challenge in this paper we provide the state of the art of the theme of escarpment retreat reviewing both the classic contributions often forgotten but important case studies and the latest research in separate parts of the paper we discuss 1 terminology applied to the geomorphology of escarpments 2 the main assumptions and pathways of long term evolution of escarpments including conceptual models presented so far 3 processes involved in cliff retreat mainly weathering mass movements and erosion 4 the role of spring erosion and fluvial processes leading to fluvial dissection and development of canyons present in many tablelands 5 the possible role of climate change in escarpment evolution 6 rates of escarpment retreat in conclusions we summarize the major advances in our understanding of escarpment evolution of the last two three decades such as the recognition of the key role of emerging groundwater in non uniform escarpment retreat of an important role of silica dissolution and underground removal of dissolved solids increasing appreciation of rock properties in governing the patterns of escarpment retreat the proposal that cliffs do not necessarily retreat via catastrophic rock slope failures but may disintegrate in situ and the first attempts to date escarpment retreat using cosmogenic isotopes finally the remaining gaps and possible research priorities for the future are identified

comparative crystal chemistry of orthosilicate minerals the earth s average mantle composition is presumed to lie between an si o atom ratio of 1 3 and 1 4 e g ita and stixrude 1992 the orthosilicate group which comprises minerals that contain isolated sio4 tetrahedra has thus been the subject of considerable structural investigation at elevated temperature or pressure the group includes olivines silicate spinels garnets the aluminosilicates zircon and a few minor mineral groups such as humites and datolites deer et al 1997 in addition the silicate spinelloids are typically included here but are not strictly orthosilicates as they contain si2o7 dimers titanite catisio5 though technically an orthosilicate has a framework structure and is considered in a chapter by ross this volume which also examines aspects of the garnet framework structure not reviewed here interestingly no natural members of the group contain major amounts of monovalent alkali cations although liscsio4 has been synthesized with the olivine structure the most geologically significant members of the group are those minerals of formula x 2sio4 where x is a divalent cation typically mg fe mn ca and more rarely co and ni these groups include the olivines the silicate spinels and wadsleyite type spinelloids plus some minor phases such as phenakite be2sio4 willemite zn2sio4 and cadmium and chromous orthosilicates the structures of most of the major members of the group have been studied at elevated temperatures or at elevated pressures but there have not yet been many studies of structures at simultaneously elevated temperature and pressure other members of the orthosilicate group that are of major geological and geophysical significance are the al2sio5 aluminosilicate polymorphs sillimanite andalusite and kyanite zircon zrsio4 and the garnets which are abundant in high pressure metamorphic rocks the structures of these

discovery controls and hazards of widespread deep seated gravitational slope deformation in the etsumi mountains central japan deep seated gravitational slope deformation dsgsd is a largely unnoticed but important long term mass wasting process that may result in catastrophic failure of mountain slopes manifested by small topographic irregularities such as ridge parallel scarps and linear depressions it has been predominantly reported in alpine landscapes above timber lines on the basis of area wide high resolution topographic data acquired by light detection and ranging lidar surveys we here show that 96 of existing gravitational scarps have been hidden under forest canopies in the etsumi mountains central japan the scarps are surprisingly widespread over the mountains with a mean line density of as large as 0 87 km km2 our analyses of the scarp distribution suggest that uphill facing scarps are primary geomorphic signals of dsgsd with a destabilized rock mass larger than 105 m2 whereas downhill facing scarps principally occur in response to more localized slope deformation in terms of controls topography is by far the most influential factor in triggering and promoting dsgsd despite the m 7 5 earthquake in 1891 impact of large local earthquakes proves to be not very strong comparison with preexisting landslide maps further suggests that dsgsd and large scale landslide are not different slope processes but represent different stages of the same process our results highlight limitation of aerial photograph interpretation in forest covered mountains and the need for lidar assisted mapping for deeper understanding of this long term process and interactions between surface and tectonic processes

dual polarity early carboniferous remagnetization of the fisset brook formation cape breton island nova scotia summary red siltstones and volcanic flows of the fisset brook formation of cape breton island nova scotia were folded or tilted in two phases one of late tournaisian and the other of mid namurian age upon thermal demagnetization both rock types yield three components of magnetization herein denoted as l i and h the l component has low unblocking temperatures and a direction conforming to that of the present day geomagnetic field l is inferred to be of recent origin the intermediate i component carried by haematite is of synfolding origin directions could be obtained through vector subtraction for the demagnetization interval of 300 550 c and yield a mean of d i 160 38 k 90 8 ag5 s lo after 39 per cent of the tilt correction is applied the h component has even higher unblocking temperatures which overlap to a large degree with those of the i component but analysis of intersecting great circles appears to yield a best fit direction for h which is nearly antipodal to that of the i component h is also synfolding and yields a mean direction of d i 342 38 k 120 9 ag5 6 9 after 60 per cent of tilt correction both components are interpreted as secondary chemical remanent magnetizations of late tournaisian to early namurian age a comparison of all available carboniferous results from the craton and the northern appalachians indicates that palaeolatitudes for nova scotia changed from about 20 s to about 10 s in the interval between the early and late namurian and that they changed again from about 10 s to 0 between the late namurian and the stephanian declinations show good agreement between newfoundland nova scotia new brunswick and the craton with the exception of the meguma terrain which underwent a counterclockwise rotation with respect to the mainland in the late carboniferous as noted previously by spariosu kent keppie 1984

stereopaired morphometric protection index red relief image maps stereo mpi rrims effective visualization of high resolution digital elevation models for interpreting and mapping small tectonic geomorphic features

high resolution electrical resistivity and aeromagnetic imaging reveal the causative fault of the 2009 mw 6 0 karonga malawi earthquake

tectonic geomorphology of the san andreas fault zone from high resolution topography an example from the cholame segment abstract high resolution topographic data along fault zones are important aids in the delineation of recently active breaks a 15 km long portion of the south central san andreas fault saf along the southern cholame segment contains well preserved tectonic landforms such as benches troughs scarps and aligned ridges that indicate recurring earthquake slip recently acquired lidar topographic data along the entire southern saf b4 project have shot densities of 3 4 m 2 computed from the lidar returns digital elevation models dems of 0 25 to 0 5 m resolution using local binning with inverse distance weighting and 0 8 m or larger search radii depict the tectonic landforms at paleoseismic sites well enough to assess them confidently mapping of recently active breaks using a lidar only based approach compares well with aerial photographic and field based methods the fault zone varies in width from meters to nearly 1 km and is comprised of numerous en echelon meter to kilometer length overlapping sub parallel fault surfaces bounding differentially moving blocks that elongate parallel to the saf the semantic variations of what constitutes active and the importance of secondary traces influence the breadth and complexity of the resulting fault trace maps

slip in the 1857 and earlier large earthquakes along the carrizo plain san andreas fault the moment magnitude mw 7 9 fort tejon earthquake of 1857 with a 350 kilometer long surface rupture was the most recent major earthquake along the south central san andreas fault california based on previous measurements of its surface slip distribution rupture along the 60 kilometer long carrizo segment was thought to control the recurrence of 1857 like earthquakes new high resolution topographic data show that the average slip along the carrizo segment during the 1857 event was 5 3 1 4 meters eliminating the core assumption for a linkage between carrizo segment rupture and recurrence of major earthquakes along the south central san andreas fault earthquake slip along the carrizo segment may recur in earthquake clusters with cumulative slip of 5 meters

3d_fault_offsets a matlab code to automatically measure lateral and vertical fault offsets in topographic data application to san andreas owens valley and hope faults measuring fault offsets preserved at the ground surface is of primary importance to recover earthquake and long term slip distributions and understand fault mechanics the recent explosion of high resolution topographic data such as lidar and photogrammetric digital elevation models offers an unprecedented opportunity to measure dense collections of fault offsets we have developed a new matlab code 3d fault offsets to automate these measurements in topographic data 3d fault offsets mathematically identifies and represents nine of the most prominent geometric characteristics of common sublinear markers along faults especially strike slip in 3 d such as the streambed minimum elevation top free face and base of channel banks or scarps minimum laplacian maximum gradient and maximum laplacian and ridges maximum elevation by calculating best fit lines through the nine point clouds on either side of the fault the code computes the lateral and vertical offsets between the piercing points of these lines onto the fault plane providing nine lateral and nine vertical offset measures per marker through a monte carlo approach the code calculates the total uncertainty on each offset it then provides tools to statistically analyze the dense collection of measures and to reconstruct the prefaulted marker geometry in the horizontal and vertical planes we applied 3d fault offsets to remeasure previously published offsets across 88 markers on the san andreas owens valley and hope faults we obtained 5 454 lateral and vertical offset measures these automatic measures compare well to prior ones field and remote while their rich record provides new insights on the preservation of fault displacements in the morphology

application of high resolution dem data to detect rock damage from geomorphic signals along the central san jacinto fault abstract we analyze geomorphic properties extracted from lidar and srtm shuttle radar topography mission data to test whether the damage zone along the central san jacinto fault sjf zone can be resolved with remotely sensed data in a quantitative fashion the sjf is one of the most active faults in southern california with well expressed geomorphology and a fast slip rate as seen in the geology and by gps we use arcmap and the taudem toolbox to compare several morphometric parameters including drainage density dd on both sides of the fault using a 1 km and a 5 km buffer for the lidar and srtm data respectively we also analyze the spatial patterns of dd near the fault using two different definitions of spatial dd the high resolution of the lidar data allows us to focus on a single fault eliminating the effects of parallel nearby faults from the lidar data we find that the highest dd values occur in areas between two fault strands followed generally by rocks on the northeast side of the fault with the lowest dd values occurring on the southwest side of the fault the srtm data shows a band of high dd values centered on the main fault trace with 1 km width our results indicate that there is a strong correlation between drainage density and proximity to the fault with zones of structural complexity along the fault displaying the highest dd we interpret this to largely be an effect of degree of rock damage as these are areas that are expected to be more damaged and field observations support this contention if we are correct then it appears that the northeast side of the sjf is generally more damaged south of the trifurcation area there is evidence that the signal is reversed on the larger scale with more damage on the southwest side of the fault inferred from the srtm data possibly caused by extension between the coyote creek and clark faults the implications of the observed asymmetry could be geological evidence for rupture propagation direction because a preferred propagation direction is predicted to produce asymmetric damage structure that would be recorded in the volume of rock surrounding a fault

high resolution topography for understanding earth surface processes opportunities and challenges abstract in the last decade a range of new remote sensing techniques has led to a dramatic increase in terrain information providing new opportunities for a better understanding of earth surface processes based on geomorphic signatures technologies such as airborne and terrestrial lidar light detection and ranging to obtain high resolution topography have opened avenues for the analysis of landslides hillslope and channellization processes river morphology active tectonics volcanic landforms and anthropogenic signatures on topography this review provides an overview of the recent flourishing literature on high resolution topographic analyses underlining their opportunities and critical issues such as their limitations the goal is to provide answers to questions such as what kind of processes can be analyzed through high resolution topographic data and how to do it the review focuses on two different environments natural and engineered landscapes in both contexts high resolution topography offers opportunities to better understand geomorphic processes from topographic signatures particular attention is given to engineered landscapes in which the direct anthropic alteration of processes is significant the last part of the review discusses future challenges

constraints on the location and mechanism of the 1511 western slovenia earthquake from active tectonics and modeling of macroseismic data abstract the 1511 western slovenia earthquake m 6 9 is the largest event occurred so far in the region of the alps dinarides junction though it strongly influences the regional seismic hazard assessment the epicenter and mechanism are still under debate the complexity of the active tectonics of the alps dinarides junction is reflected by the presence of both compressional and transpressional deformations this complexity is witnessed by the recent occurrence of three main earthquake sequences the 1976 friuli thrust faulting events the 1998 bovec krn mountain and the 2004 kobarid strike slip events the epicenters of the 1998 and 2004 strike slip earthquakes ms 5 7 and ms 4 9 respectively lie only 50 km far from the 1976 thrust earthquake ms 6 5 we use the available macroseismic data and recent active tectonics studies to assess a possible epicenter and mechanism for the 1511 earthquake and causative fault according with previous works reported in the literature we analyze both a two and a single event case defining several input fault models we compute synthetic seismograms up to 1 hz in an extended source approximation testing different rupture propagations and applying a uniform seismic moment distribution on the fault segments we extract the maximum horizontal velocities from the synthetics and we convert them into intensities by means of an empirical relation a rounded to integer misfit between observed and computed intensities is performed considering both a minimized and a maximized databases built to avoid the use of half degree macroseismic intensity data points our results are consistent with a 6 9 magnitude single event rupturing 50 km of the idrija right lateral strike slip fault with bilateral rupture propagation

evolution of a high level high silica magma chamber the pattison pluton nisling range alaskites yukon the pattison pluton is a high level high silica tertiary alaskite intruding rocks of the yukon crystalline terrane the pluton is roughly circular in form with a diameter of about 18 km the intrusion is cut by a series of shallowly dipping aplite dikes mineralogically the alaskite body and the aplite dikes are very similar but the pluton is divided into a series of phases based on texture and stratigraphic position a fine grained upper border phase a medium grained graphic strongly miarolitic porphyritic phase and a lower coarser grained phase contacts being gradational no strong major element trends are found within the pluton including the aplite dikes because of eutectic crystallization the trace elements particularly ba sr rb zr and the ree however do show a liquid line of descent with the upper border phase as the least differentiated and the aplite dikes as the most differentiated phases rayleigh fractional crystallization of quartz k feldspar and plagioclase and access

550 580 ma magmatism in cape breton island nova scotia canada the product of nw dipping subduction during the final stage of amalgamation of gondwana abstract cape breton island is host to widespread magmatic activity dated between 550 and 580 ma in the south its products include the capelin cove pluton and host coastal volcanic belt both are composed of bimodal tholeiitic calc alkaline suites that were emplaced on a thin sialic crust in a volcanic arc system their trace element and nd isotope variations are consistent with fractional crystallization accompanied by lower crustal contamination in a compositionally zoned magma chamber in contrast the indian brook and kerrs brook plutons and price point volcanic rocks in central cape breton island have higher contents of strongly incompatible trace elements and resemble modern arc related calc alkaline rocks emplaced on a moderately thick continental crust comparison with available data for other 550 580 ma igneous rocks across cape breton island indicates that they were produced above a nw dipping subduction zone this convergence was synchronous with the final stage of globalscale orogenic activity that culminated with the final amalgamation of gondwana available detrital zircon ages in late neoproterozoic 650 545 ma sediments in the antigonish highlands avalon composite terrane suggest derivation from the amazon craton it is proposed that the avalon composite terrane formed off northwestern south america during the late neoproterozoic

application of the topographic position index to heterogeneous landscapes topographic position index tpi is an algorithm increasingly used to measure topographic slope positions and to automate landform classifications we applied tpi to a geoarchaeological research project in northwestern belgium but its use led to erroneous landform classifications in this heterogeneous landscape we asked whether deviation from mean elevation dev was a better method for landform classification than tpi we found that it enabled more accurate geomorphological assessment when using northwestern belgium as a case study

recovering paleoearthquake slip record in a highly dynamic alluvial and tectonic region hope fault new zealand from airborne lidar knowing the slip amplitudes that large earthquakes produced in prehistorical times is one key to anticipate the magnitude of large forthcoming events it is long known that the morphology is preserving remnants of paleoearthquake slips in the form of fault offset landforms however the measured offsets that can be attributed to the most recent paleoearthquakes are generally few along a fault so that they rarely allow recovering the slip distributions and largest slips of these earthquakes we acquired 1 m resolution airborne lidar data on a 30 km stretch of a fast slipping strike slip fault eastern hope fault new zealand located in a region of high alluvial dynamics where landforms are rapidly evolving data analysis reveals 200 offset landforms only 30 allow a good to moderate quality offset measurement from these good to moderate quality measures we recover the slip length distributions and largest slips of the four most recent large paleoearthquakes and find evidence of 4 6 prior events the record suggests that large earthquake slip recurred in multiples of about 4 m along the 30 km stretch although they have larger uncertainties the more numerous lower quality offsets that we also measured reveal a similar earthquake slip record this shows that although offset landforms are partly degraded in dynamically active landscapes they store valuable information on paleoearthquake slips this information might be recovered provided that the morphology is analyzed at high resolution and continuously over a significant fault length remote lidar data are powerful to perform such analyses

relation of the spectroscopic reflectance of olivine to mineral chemistry and some remote sensing implications using high resolution visible and near infrared diffuse spectral reflectance we have systematically investigated apparent wavelength shifts as a function of mineral chemistry in the fe mg olivine series from fo11 to fo91 the study also shows that trace amounts of nickel can be spectrally detected in the olivine structure we show that significant compositional information can only be extracted at relatively high resolution because the overall spectral characteristics of the olivines change only subtly as a function of the fe mg ratio significant spectral variation as a function of grain size is also demonstrated adding a further complication to the interpretation of remotely sensed data from olivine rich surfaces this laboratory study is expected to aid in the interpretation of remotely sensed data from both terrestrial and extraterrestrial bodies terrestrial applications may include the recognition of ultramafic ultrabasic and basaltic terrains which in themselves may have mineral potential among extraterrestrial applications the asteroids are obvious candidates for further examination if instrumentation can provide the necessary wavelength coverage resolution and signal to noise ratio so that spectra can be compared to those laboratory data discussed here some permutations of fe mg ni relations in olivines are discussed as they apply to the interpretation of asteroid surfaces and other extraterrestrial bodies

major and minor element site occupancies in heated natural forsterite using a new analytical transmission electron microscopic technique known as channelling enhanced x ray emission chexe spectroscopy the m site occupancies of fe ni mn and ca have been determined in a natural forsteritic olivine fo sub 91 heat treated at different temperatures the sample was taken as a single olivine grain from a spinel peridotite inclusion in an alkali basalt and contains 0 36 wt nio 0 07 wt mno and 0 09 wt cao in the non heat treated sample 49 6 at of the fe 97 5 at of the mn in the sample occupy the m1 site in the present study of samples quenched from different temperatures the fraction of the ni present at m1 is 87 5 6 days at 300 sup 0 c 83 5 48h at 600 sup 0 c 83 5 45h at 900 sup 0 c and 80 5 24h at 1050 sup 0 c the authors observed a lesser tendency for ni to order than postulated by previous workers for ni rich olivines for mn typically 15 of the atoms occupy m1 in the heat treated samples no significant deviation from complete ordering into m2 was observed for ca the fe atoms are completely disordered with 50 1 at eachmore m site except for a weak deviation at 300 sup 0 c with 47 1 1 at m1 the study indicates that exchange of cations between m sites may begin as low as 300 sup 0 c this implies that ni and mn distribution in natural olivines may be a useful indicator of cooling rate in rapidly cooled rocks less

the evolution of the avalonian plate abstract the avalon platform of newfoundland is the type locality of the avalonian plate that is characterized by late precambrian volcanic and clastic rocks marine at the bottom and terrestrial at the top all are intruded by 650 550 ma granites late precambrian rocks in the southern british isles are similar in both areas northeastern parts of the belt are affected by deformation and metamorphism that have orogenic aspects the orogeny is referred to as the avalonian in newfoundland and monian in britain to the southeast of the avalonian rocks in europe lies another late precambrian cadomian orogenic belt of rocks as a part of the pan african orogenic belt the cadomian and avalonian belts extend into north africa morocco since these belts are ophiolite bearing it is suggested that the plate was bordered by oceanic domains it is therefore proposed that a microcontinental volcanic arc that was generated in the late precambrian was orogenically deformed by collision with north america europe and africa and survived as a coherent terrain until the late carboniferous

tectonic implications of the gps velocity field in the northern adriatic region 1 continuous and episodic gps observations between 1991 and 2004 show that adria moves independently of both stable eurasia and nubia adria moves nne at 3 4 5 mm yr increasing from n to s relative to eurasia and may be fragmenting along the gargano dubrovnik seismic zone the observed 2 3 mm yr of n s adria eurasia convergence is taken up by contraction across a narrow 70 km zone in the eastern alps and concomitant extrusion of the alpine north pannonian unit the adria central dinarides boundary is a broader collisional zone with intense 1 1 5 mm yr shortening near shore and 2 mm yr spread across the dinarides the remaining 1 2 mm yr motion e of the alps and ne of the dinarides is absorbed by the inverted contracting pannonian basin leaving no significant deformation above 0 5 mm yr in the western and northern carpathians and european platform

finding the buried record of past earthquakes with gpr based palaeoseismology a case study on the hope fault new zealand in places where sedimentation and erosion compete at fast rates part of the record of past earthquakes on faults may be buried hence hidden in the first few metres below the surface we developed a novel form of palaeoseismology of geophysical type based on the use of a dense pseudo 3 d ground penetrating radar gpr survey to investigate such possible buried earthquake traces on a long fast slipping strike slip fault hope fault new zealand at a site terako where marked alluvial conditions prevail we first used lidar data to analyse the ground surface morphology of the 2 km2 site at the greatest resolution nineteen morphological markers were observed mainly alluvial terrace risers and small stream channels that are all dextrally offset by the fault by amounts ranging between 3 and 200 m the measurements document about 10 past earthquake slip events with a mean coseismic slip of 3 3 1 m with the most recent earthquake event having a slip of 3 0 5 m we then investigated a detailed area of the site 400 x 600 m2 with pseudo 3 d gpr we measured 56 similar to 400 m long 510 m spaced gpr profiles 250 mhz parallel to the fault and evenly distributed on either side the analysis revealed the existence of a palaeosurface buried at about 3 m depth corresponding to the top of alluvial terraces of different ages that buried surface is incised by a dense network of stream channels that are all dextrally offset by the fault we measured 48 lateral offsets in the buried channel network more than twice than at the surface these offsets range between 6 and 108 m as observed at the surface yet provide a more continuous record of the fault slip the similarity of the successive slip increments suggests a slip per event averaging 4 4 1 m fairly similar to that estimated from surface data from the total surface and buried 67 offset collection we infer that a minimum of 30 large earthquakes have broken the hope fault at the terako site in the last about 67 kyr with an average coseismic slip of 3 2 1 m a minimum average recurrence time of about 200 yr and a magnitude of at least mw 7 07 4 our study therefore confirms that part of the record of past earthquakes may indeed reside in the first few metres below the surface where it may be explored with geophysical gpr based palaeoseismology developing such a new palaeoseismological tool should provide rich information that may complement surface observations and help to document the past earthquakes on faults

active tectonics in 4d high resolution abstract with a little more than 100 years since the publication of seminal and field defining investigations active tectonics is still a relatively young sub discipline of structural geology this research field addresses the accumulation of strain due to plate tectonic motion and more importantly release thereof through the occurrence of earthquakes or other strain releasing events in that regard active tectonics aims to characterize the incremental steps of plate tectonics determining earthquake chronologies fault slip rates and other common objectives importantly feed into our understanding of for example fault mechanics and crustal rheology characterizing the recurrence of large and potentially devastating earthquakes is further motivated by seismic hazard assessment and risk mitigation the primary data source in active tectonics is surface and shallow subsurface evidence of faulting presenting itself in topographic and stratigraphic data sets respectively field observations and air photo interpretation of displaced stratigraphic and geomorphic markers were used almost 40 years ago to formulate end member models of earthquake recurrence technological developments since then especially within the last two decades have dramatically increased the abundance and resolution of topographic data sets and the ability to date stratigraphic units and geomorphic surfaces enabling the formulation of better informed conceptual models of earthquake recurrence here we provide an overview of the high resolution topographic data sets and dating methods that enabled the recent advances of active tectonics

fault zone structure from topography signatures of en echelon fault slip at mustang ridge on the san andreas fault monterey county california 1 we used high resolution topography to quantify the spatial distribution of scarps linear valleys topographic sinks and oversteepened stream channels formed along an extensional step over on the san andreas fault saf at mustang ridge california this location provides detail of both creeping fault landform development and complex fault zone kinematics here the saf creeps 10 14 mm yr slower than at locations 20 km along the fault in either direction this spatial change in creep rate is coincident with a series of en echelon oblique normal faults that strike obliquely to the saf and may accommodate the missing deformation this study presents a suite of analyses that are helpful for proper mapping of faults in locations where high resolution topographic data are available furthermore our analyses indicate that two large subsidiary faults near the center of the step over zone appear to carry significant distributed deformation based on their large apparent vertical offsets the presence of associated sag ponds and fluvial knickpoints and the observation that they are rotating a segment of the main saf several subsidiary faults in the southeastern portion of mustang ridge are likely less active they have few associated sag ponds and have older scarp morphologic ages and subdued channel knickpoints several faults in the northwestern part of mustang ridge though relatively small are likely also actively accommodating active fault slip based on their young morphologic ages and the presence of associated sag ponds

large scale ground deformation of etna observed by gps between 1994 and 2001 we have processed thirty global positioning system gps campaigns carried out at etna from 1994 to early 2001 between the last two main flank eruptions of the mt etna sicily italy this rest period allowed us to investigate the deep magma plumbing system of the mt etna the temporal dynamics of twenty three points observed three times or more were analyzed all the time series show a first order linear trend during the five years period it suggests that the volcano was continuously deformed by the action of a deep source while a discrete activity of the volcano was observed at the summit we have interpreted the residual deformation field as the result of an major eastward motion of the eastern flank of the volcano

contrasting u pb ages from plutons in the bras d or and mira terranes of cape breton island nova scotia u pb dates from zircon titanite and monazite in plutons of the bras d or and mira terranes of southern cape breton island combined with 40ar 39ar and other radiometric age data indicate that th

coseismic fault zone deformation revealed with differential lidar examples from japanese mw 7 intraplate earthquakes abstract we use two recent japanese earthquakes to demonstrate the rich potential as well as some of the challenges of differencing repeat airborne light detection and ranging lidar topographic data to measure coseismic fault zone deformation we focus on densely vegetated sections of the 14 june 2008 iwate miyagi m w 6 9 and 11 april 2011 fukushima hamadori m w 7 1 earthquake ruptures each covered by 2 m resolution pre event and 1 m resolution post event bare earth digital terrain models dtms obtained from commercial lidar providers three dimensional displacements and rotations were extracted from these datasets using an adaptation of the iterative closest point icp algorithm these displacements remain coherent close to surface fault breaks as well as within dense forest despite intervals of 2 years iwate miyagi and 4 years fukushima hamadori encompassed by the lidar scenes differential lidar analysis is thus complementary to interferometric synthetic aperture radar insar and sub pixel correlation techniques which often break down under conditions of long time intervals dense vegetation or steep displacement gradients although the icp displacements are much noisier than overlapping insar line of sight displacements they still provide powerful constraints on near surface fault slip in the fukushima hamadori case near fault displacements and rotations are consistent with decreased primary fault slip at very shallow depths of a few tens of meters helping to account for the large along strike heterogeneity in surface offsets observed in the field this displacement field also captures long wavelength deformation resulting from the 11 march 2011 tohoku great earthquake

boulder aprons indicate long term gradual and non catastrophic evolution of cliffed escarpments stolowe mts poland abstract caprock crowned escarpments are characteristic geomorphic features of the sandstone tableland of the stolowe mountains sw poland their mid and lower slopes truncate weaker sedimentary formations but are littered with sandstone boulders of various size often more than 5 m long which form nearly continuous aprons a model of escarpment retreat by rock fall has been widely accepted in literature but in the stolowe mountains it has never been tested against field evidence in addition no rock fall events except one minor fall in 1921 have been recorded in historical times in this paper we erected five hypotheses of how escarpments may have evolved through time to result in widespread boulder presence on the slopes mapping boulder extent and slope morphology run out distance simulations using conefall software and rock strength determinations using the schmidt hammer carried out on boulders along eight representative slope profiles provide data about characteristics of the boulder covers systematic decrease in intact rock strength with an increasing distance from the sandstone cliffs suggests that the boulder aprons are diachronic and record long term retreat of escarpments there exists no conclusive evidence of widespread boulder downslope movement although in a few localities shallow landslides have rafted boulders far away from the cliff lines modelling exercise shows that the actual extent of boulders is 2 3 times bigger than suggested by conefall predictions these findings coupled with observations along the cliff lines themselves lead us to propose a model of free face in situ disintegration as the most likely hypothesis to explain block detachment and release from rock faces as cliff lines recede and the slope surface below is lowered remnant boulders occupy a position increasingly further away from escarpment rims but experience little actual movement this model complements the existing models of tableland evolution which tend to emphasize catastrophic mass movement processes on cliffed escarpments

a fault scarp in an urban area identified by lidar survey a case study on the itoigawa shizuoka tectonic line central japan abstract a light detection and ranging lidar survey was conducted in a densely built up area to generate a high resolution digital elevation model dem to look for active faults the urban district of matsumoto city in central japan is located in a 3 km 2 basin along the itoigawa shizuoka tectonic line active fault system one of japanese onshore fault systems with the highest earthquake probability a high resolution dem at a 0 5 m grid interval was obtained after removing the effects of laser returns from buildings clouds and vegetation it revealed a continuous scarp up to 2 m in height borehole data and archaeological studies indicate the scarp was formed during the most recent faulting event associated with historical earthquakes in addition the fault scarp strongly supports that the urban district is in a pull apart basin related to a fault step over between two left lateral strike slip faults consequently accurate interpretation of fault geometry is crucial to provide estimates of future surface deformation and to allow modeling of basin structure and strong ground motion thus the lidar mapping survey in urban districts is effective for detailed active fault mapping in order to constrain basin structure and to forecast the exact location of surface rupturing associated with large earthquakes

scismotectonics of the northwest external dinarides abstract the region of the tectonic contact between the alps and the dinarides is studied comparing all the available geological geophysical and seismological data the peculiar crustal structures in particular the difference in thickness of the alps dinarides and pannonian basin can be correlated to the seismically active zones the highest seismicity is related to the adria microplate underthrusting the southern alps beneath the friulian piedmont arc this movement produces a composite lateral slip and an underthrust which is subparallel to the dinarides along the yugoslav coast the seismicity in western yugoslavia is more diffuse than in friuli although it is possible to pick out three narrow parallel bands with dextral shear subparallel to the periadriatic vardar fault system which separate the apulia from the pannonian area the interaction of this system with the sinistral strike slip faults of the western carpathians belt enhances the seismicity of the easternmost sector of the alps analogies and differences in the seismotectonic behaviour between central friuli and western yugoslavia are studied and a unique model with a vertical mechanical disengagement at the rear of the compressive fronts of the southern alps and external dinarides is proposed

neo alpine structural evolution and present day tectonic activity of the eastern southern alps the case of the ravne fault nw slovenia abstract the ravne fault is an actively propagating nw se trending dextral strike slip fault in the julian alps of nw slovenia which has been responsible for two moderate sized earthquakes in the last decade strike slip displacements on moderate steep fault planes are responsible for the recent seismic activity that is confined to shallow crustal levels the fault is growing by interaction of individual right stepping fault segments and breaching of local transtensional step over zones the fault geometry is controlled by the original geometry of the nw se trending thrust zone modified by successive faulting within the fault zone in the modern n directed maximum horizontal stress regime the segmented fault is lengthening by active growth at the fault s nw end the spatial distribution of earthquake clusters shows that activity on strike slip segments and thrust faults is contemporaneous detailed analysis of the spatial pattern of earthquake events and surface fault geometries suggests that for earthquakes of similar magnitudes and similar fault kinematics the deciding factor for whether an earthquake rupture will breach a step over zone is the relationship between the lengths of individual neighbouring fault segments and fault separation distances in the step over zones the ravne fault represents an example of a tectonic structure that lies in an area subjected to multiple tectonic events under different regional stress conditions at epicentral depths the fault system is accommodating recent strain along newly formed fault planes whereas in upper parts of the crust the activity is distributed over a wider deformation zone that includes reactivated brittle thrust faults

fault slip distribution of the 1999 mw 7 1 hector mine earthquake california estimated from postearthquake airborne lidar data the 16 october 1999 hector mine earthquake m w 7 1 was the first large earthquake for which postearthquake airborne light detection and ranging lidar data were collected to image the fault surface rupture in this work we present measurements of both vertical and horizontal slip along the entire surface rupture of this earthquake based on airborne lidar data acquired in april 2000 we examine the details of the along fault slip distribution of this earthquake based on 255 horizontal and 85 vertical displacements using a 0 5 m digital elevation model derived from the lidar imagery the slip measurements based on the lidar dataset are highest in the epicentral region and taper in both directions consistent with earlier findings by other works the maximum dextral displacement measured from lidar imagery is 6 60 1 10 m located about 700 m south of the highest field measurement 5 25 0 85 m our results also illustrate the difficulty in resolving displacements smaller than 1 m using lidar imagery alone we analyze slip variation to see if it is affected by rock type and whether variations are statistically significant this study demonstrates that a postearthquake airborne lidar survey can produce an along fault horizontal and vertical offset distribution plot of a quality comparable to a reconnaissance field survey although lidar data can provide a higher sampling density and enable rapid data analysis for documenting slip distributions we find that relative to field methods it has a limited ability to resolve slip that is distributed over several fault strands across a zone we recommend a combined approach that merges field observation with lidar analysis so that the best attributes of both quantitative topographic and geological insight are utilized in concert to make best estimates of offsets and their uncertainties

contribution to the theory of scarpland development from observations in central queensland australia abstract theories of scarpland geomorphology developed over the past century have been characterized by divergent conceptual frameworks and have been hindered by language barriers here we review the main theories and assess them with reference to field evidence from central queensland this region provides exceptional scope for such an assessment because of the detailed k ar chronology available for basalt that is draped extensively over scarps and valleys the basalt provides the key to deciphering the pattern and rate of denudation erosion began in the late mesozoic and was greatly advanced when volcanism occurred during the middle cenozoic postbasaltic erosion has been dominated by the incision of the basaltic caprock and by the lengthening of canyons rather than by scarp retreat canyons have extended headward by 1 2 km m yr widened by 150 250 m m yr and deepened by 6 25 m m yr while scarps between canyons have retreated by only 18 130 m m yr canyon cutting both on the scarp front and on t

the 1998 bovec krn mountain slovenia earthquake sequence we study the 1998 bovec krn mountain slovenia earthquake sequence by combining hypocenters relocation strong motion inversion digital elevation modelling and field geology the main shock ms 5 7 a 12 km right lateral strike slip event on the dinaric fault system occurred on a sub vertical fault plane the rupture confined between 3 and 9 km depth with no evidence of surface faulting propagated bilaterally within two structural barriers the northwestern barrier is at the junction between dinaric and alpine structures where there is a sharp change in the geometry of faulting the southeastern barrier is within the dinaric system and its surface expression corresponds to the tolminka spring perched basin a 1 km restraining step over at this site the bovec krn earthquake fault overlaps with a 30 km strike slip fault segment that is free of aftershocks and could be undergoing an increase of stress this fault system represents the northern branch of the idrija right lateral fault

application of airborne lidar to mapping seismogenic faults in forested mountainous terrain southeastern alps slovenia results are presented of the first airborne lidar survey ever flown in europe for the purpose of mapping the surface expression of earthquake prone faults detailed topographic images derived from lidar data of the idrija and ravne strike slip faults in nw slovenia reveal geomorphological and structural features that shed light on the overall architecture and kinematic history of both fault systems the 1998 mw 5 6 and 2004 mw 5 2 ravne fault earthquakes and the historically devastating 1511 m 6 8 idrija earthquake indicate that both systems pose a serious seismic hazard in the region because both fault systems occur within forested terrain a tree removal algorithm was applied to the data the resulting images reveal surface scarps and tectonic landforms in unprecedented detail importantly two sites were discovered to be potentially suitable for fault trenching and palaeo seismological analysis this study highlights the potential contribution of lidar surveying in both low relief valley terrain and high relief mountainous terrain to a regional seismic hazard assessment programme geoscientists working in other tectonically active regions of the world where earthquake prone faults are obscured by forest cover would also benefit from lidar maps that have been processed to remove the canopy return and reveal the forest floor topography

synchronized gravitational slope deformation and active faulting a case study on and around the neodani fault central japan abstract earthquakes are considered to be important triggers of deep seated gravitational slope deformation dgsd in seismically active regions and if that is the case dgsd features could be candidates for off fault paleoseismology investigations on the basis of pit excavations and sediment cores at an off fault dgsd site and a trench excavation across the active neodani fault at a nearby site we examined the records of dgsd and surface rupturing paleoearthquakes of the neodani fault the four most recent dgsd events were dated at after 240 cal bp 1710 340 cal bp 4730 3970 cal bp and 5570 5340 cal bp the four most recent surface rupturing earthquakes were dated at 1891 ce the nobi earthquake 2010 1220 cal bp 7180 2110 cal bp and before 9540 cal bp we conclude that the ages of the four dgsd events are consistent with surface rupturing earthquakes on the adjacent neodani fault we infer that static crustal strain from repeated seismogenic faulting plays an important role in the occurrence of dgsd events at least in the immediate vicinity of active faults although coseismic severe shaking would have at least some effect on them our case study suggests that off fault dgsds can be used to reconstruct or refine the paleoseismic history of a nearby active fault we propose that an ideal dgsd for that purpose would be located in an area of concentrated strain near a termination bend or stepover of the target fault

age and tectonic setting of granitoid plutons in the cheticamp belt western cape breton island nova scotia canada geological mapping in the cheticamp granitoid belt in combination with petrographic and geochemical studies and u pb zircon dating by laser ablation inductively coupled plasma mass spectrometry have resulted in major reinterpretation of the geology in the western part of the ganderian aspy terrane of cape breton island nine new u pb zircon ages show that the former cheticamp pluton consists of 10 separate plutons of five different ages late neoproterozoic ca 567 ma cambrian ordovician 490 482 ma ordovician silurian 442 440 ma mid silurian ca 428 ma and late devonian 366 ma the three late neoproterozoic granodioritic to monzogranitic plutons are older than the adjacent metavolcanic and metasedimentary rocks of the jumping brook metamorphic suite whereas the tonalitic to quartz dioritic cambrian ordovician plutons intruded those metamorphic rocks petrographic characteristics and approximately 100 whole rock chemical analyses show that with the exception of the mid silurian grand falaise alkali feldspar granite which has a type within plate characteristics the plutonic units have calc alkaline affinity and were emplaced in a volcanic arc tectonic setting these results are evidence that fragments of a long history of episodic subduction related magmatism and terrane collision are preserved in this small part of ganderia eight new sm nd isotopic analyses are consistent with the ganderian affinity of the cheticamp plutonic belt the ca 490 482 ma plutons are the first direct evidence in cape breton island for the penobscottian event recognized in the exploits subzone of central newfoundland and in new brunswick however the structural relationship of the cheticamp plutonic belt to the rest of the aspy and bras d or terranes remains enigmatic as is the apparent absence of effects of devonian deformation and metamorphism in the older plutonic units

geomorphic response to uplift along the dragon s back pressure ridge carrizo plain california we used high resolution topography geomorphic mapping of active surface processes and geologic mapping to study the topographic and erosional response of small drainage basins to rock uplift along the dragon s back pressure ridge along the san andreas fault in the carrizo plain california we infer the history of deformation experienced by 40 small drainage basins formed in poorly consolidated sedimentary rocks a space for time substitution directly images the erosional and topographic responses to deformation progressive deformation and rock uplift are accompanied by increases in channel steepness and basin relief as uplift ceases channel concavity rapidly increases causing channels to undercut hillslopes this undercutting promotes the consumption of hillslopes by landsliding this undercutting also causes basin relief to be greatest after uplift has stopped this analysis indicates that channels of the dragon s back pressure ridge respond to changes in rock uplift rates over thousands of years whereas hillslope processes may take more than an order of magnitude longer to adjust to changes in rock uplift rates our study directly measures changes in erosional processes due to the initiation and cessation of rock uplift which can typically only be inferred using numerical models by direct field observations

use of lidar derived images for mapping old landslides under forest large deep seated landslides are common features in the flemish ardennes belgium as most of these old 100 years landslides are located under forest in this hilly region aerial photograph interpretation is not an appropriate landslide mapping method this study tested the potential of lidar light detection and ranging images for mapping old landslides under forest landslide inventory maps were created for a 125 km2 area by applying the expert knowledge of seven geomorphologists to lidar derived hillshade slope and contour line maps in a gis environment each of the seven lidar based landslide inventories was compared i with the other six ii with a detailed field survey based inventory and iii with a comparable study in which topographic data were extracted from a topographical map the combination of the percentage of field landslides indicated by an expert and the percentage of positional discrepancies expressed in terms of positional mismatch were used to evaluate the quality of the lidar based inventory maps high quality lidar derived landslide inventory maps contain more than 70 per cent of the landslides mapped during the field survey and have positional discrepancies smaller than 70 per cent when compared with the field survey based inventory map four experts and the combination map of all experts satisfied these criteria together the seven experts indicated all landslides mapped in the field importantly lidar enabled the experts to find ten new landslides and to correct the boundaries of eleven of the 77 landslides mapped during the field survey hence this study showed that large scale lidar derived maps analysed by experienced geomorphologists can significantly improve field survey based inventories of landslides with a subdued morphology in hilly regions copyright 2006 john wiley sons ltd

the seismotectonic characteristics of slovenia slovenia with its neighbouring areas lies at the junction of the alps the dinarides and the pannonian basin these belong to the three plates europe adria and tisza on the slovenian territory itself converge the external dinarides nw se oriented right lateral strike slip faults the transdanubian range ne sw oriented left lateral strike slip faults and the southern alps e w oriented thrusts the direction of the principal stress 1 azimuth 6 dip 8 is determined under the assumption of uniform stress throughout the region dip of the least principal stress 3 of 5 is consistent with the regional strike slip regime listed structures form a pure shear structural mechanism on a regional scale

landscape evolution and deduction of surface deformation in the soan dun nw himalaya india abstract the consequence of strain accumulation along various himalayan thrusts is manifested in shaping the topography and present day lanscape features of the himalaya consequently the strain accomodation is attributed to the occurrence of various devastating earthquakes in the himalayan domain including 1905 kangra earthquake mw 7 8 which occurred along the kangra valley fault in the present study we analyzed and estimatedsss fault related parameters gradient length anomaly gla analysis together with interferometric synthetic aperture radar in sar measurements to understand the landscape evolution and deformation pattern within the soan dun piggy back basin in the northwest himalayan front we combined the results of geodetic geological geomorphology and insar to constrain the uplift and subsidence between himalayan frontal thrust hft and main boundary thrust mbt zones the estimated results of fault parameters reveal that the horizontal shortening of northwest himalaya is higher than the vertical uplift the computed values of gla magnitude analysis for the uplifted region vary from 9 21 to 0 77 whereas these range from 5 48 to 26 60 for the subsided region the depicted range of vertical deformation observed from the insar measurements ranges from 3 13 to 3 14 mm y where the positive and negative value of phases are correlated with the ground uplift and subsidence the rate of deformation observed from persistent scatterer interferometry psi phase velocity and gla magnitude is positively supported by the chronologically constrained uplift rates as 3 4 0 3 mm y the geomorphic evidences such as folded tilted and truncated alluvial fan surfaces offsetting of channels fault scarps and displaced sedimentary sequences indicate active nature of the soan dun the study would be eventually useful for seismic hazard assessment and future infrastructure development in the seismotectonically active regions like soan dun of nw himalayan front

origin and holocene geomorphological evolution of the landslide dammed basin of la narse de la sauvetat massif central france this work is the first geomorphological analysis of la narse de la sauvetat a hydromorphic basin located in the southern limagne plain french massif central which had never been studied despite its great palaeoenvironmental interest we explore the potential of its sedimentary archives to provide valuable data on holocene geomorphic dynamics and their sensitivity to local and regional hydro climatic changes in order to characterize the nature and the morphostratigraphic and pedosedimentary evolution of the basin we used an integrative approach involving geomorphological mapping hand auger stratigraphic cross sections topographic analysis based on lidar data and stereophotogrammetric reconstruction geophysical prospection and radiocarbon dating results revealed a palaeotopography fossilized under 6 m of sedimentary infilling with a clear shift from fluvial to hydromorphic conditions circa 2800 cal bce separated by a level with colluvial and lacustrine features a detailed analysis of the eastern border of the basin also suggests the existence of a former open valley in place of the current closed depression now locked in by a topographic threshold forming a dam the sedimentary aggradation of the basin started with an alluvial phase during the upper pleistocene and probably continued into the middle and late holocene consistently with regional alluvial dynamics in the early subboreal a massive landslide occurred on the western slopes of the puy de corent volcanic plateau thereby damming the valley and forming a closed depression this episode coincided with the mid holocene climatic shift and an associated phase of slope instability and increased landslides in western europe due to changing climatic conditions this depression evolved into a hydromorphic basin with several high energy hydro sedimentary episodes after 2800 cal bce however hydro sedimentary conditions gradually became more stable towards the late holocene around 500 cal ce the drainage deteriorated towards palustrine conditions and caused the formation of a marsh and its consequent evolution into a shallow lake throughout the middle ages this lake was drained in the late xviiith century the long term sedimentary record of la narse de la sauvetat sensitive to climatic instability periods of the middle holocene makes this landslide dammed basin a valuable site with an important potential to further development of palaeoenvironmental and geoarchaeological studies

morphotectonic analysis of the long term surface expression of the 2009 l aquila earthquake fault central italy using airborne lidar data abstract in this paper we present a morphotectonic study of the paganica san demetrio fault system psdfs responsible for the mw6 1 april 6 2009 earthquake l aquila central italy the discrepancy observed between the length of the seismologic geodetic modeled fault the limited size of the primary coseismic surface ruptures and the significant morphological expression of the psdfs stimulated a debate about the maximum rupture length of the psdfs and its capability to generate larger magnitude events to image the psdfs long term morphological expression and define its surface geometrical arrangement length number of fault splays and boundaries we took advantage of a high resolution airborne lidar dataset lidar topography substantially increased our confidence in detecting even subtle tectonic controlled morphologies we define the psdfs as a 19 km long fault system that displays a complex structural setting characterized by two different sectors 1 the paganica sector to the nw with a narrow deformation zone and 2 the san demetrio sector to se where the strain is accommodated by several fault splays dissecting a wider quaternary basin we also defined a first order hierarchy among the numerous fault splays across the psdfs the long term geomorphic expression of the psdfs suggests that it ruptured also involving the whole 19 km long structure besides rupturing only small sections as it occurred in 2009 this suggests a variable slip behavior empirical relations applied to this hypothesis allow up to m 6 6 earthquakes along the psdfs these results have a critical impact on the seismic hazard assessment of the area when compared with a m 6 1 event as the 2009

late holocene earthquakes on the toe jam hill fault seattle fault zone bainbridge island washington five trenches across a holocene fault scarp yield the first radiocarbon measured earthquake recurrence intervals for a crustal fault in western washington the scarp the first to be revealed by laser imagery marks the toe jam hill fault a north dipping backthrust to the seattle fault folded and faulted strata liquefaction features and forest soil a horizons buried by hanging wall collapse colluvium record three or possibly four earthquakes between 2500 and 1000 yr ago the most recent earthquake is probably the 1050 1020 cal calibrated yr b p a d 900 930 earthquake that raised marine terraces and triggered a tsunami in puget sound vertical deformation estimated from stratigraphic and surface offsets at trench sites suggests late holocene earthquake magnitudes near m7 corresponding to surface ruptures 36 km long deformation features recording poorly understood latest pleistocene earthquakes suggest that they were smaller than late holocene earthquakes postglacial earthquake recurrence intervals based on 97 radiocarbon ages most on detrital charcoal range from 12 000 yr to as little as a century or less corresponding fault slip rates are 0 2 mm yr for the past 16 000 yr and 2 mm yr for the past 2500 yr because the toe jam hill fault is a backthrust to the seattle fault it may not have ruptured during every earthquake on the seattle fault but the earthquake history of the toe jam hill fault is at least a partial proxy for the history of the rest of the seattle fault zone

detection of subtle tectonic geomorphic features in densely forested mountains by very high resolution airborne lidar survey abstract despite successes elsewhere in the world 2 m resolution dems from a standard airborne lidar survey failed to detect small tectonic geomorphic features in densely forested high relief mountains of central japan our new 0 5 m dems from an unprecedentedly high resolution lidar survey along the neodani fault now reveal a number of previously unknown fault scarps as well as other hidden geomorphic features the survey achieves a ground return density of 6 2 m 2 out of a total shot density of as much as 12 7 m 2 the main factor to gain sufficient ground returns in unfavorable conditions is a large side lap of 70 between flight swaths which means that any specific area in the target zone is scanned three or more times from different angles evaluation of dems with resolution from 0 25 to 10 m assures that a 0 5m resolution lidar dem is necessary for the detection of subtle tectonic breaks another key factor for complete detection of small tectonic geomorphic features is the application of a recently developed dem visualization red relief image map rrim which allows mapping of all the small features with various sizes orientations and morphology overcoming major drawbacks of classic dem visualizations a very high resolution lidar survey aided with rrim visualization as used in this study provides a more reliable approach for the detailed mapping of slight active fault traces hidden under dense vegetation