lidar assisted identification of an active fault near truckee california abstract we use high resolution 1 5 2 4 points m 2 bare earth airborne light detection and ranging lidar imagery to identify map constrain and visualize fault related geomorphology in densely vegetated terrain surrounding martis creek dam near truckee california bare earth lidar imagery reveals a previously unrecognized and apparently youthful right lateral strike slip fault that exhibits laterally continuous tectonic geomorphic features over a 35 km long zone if these interpretations are correct the fault herein named the polaris fault may represent a significant seismic hazard to the greater truckee lake tahoe and reno carson city regions three dimensional modeling of an offset late quaternary terrace riser indicates a minimum tectonic slip rate of 0 4 0 1 mm yr mapped fault patterns are fairly typical of regional patterns elsewhere in the northern walker lane and are in strong coherence with moderate magnitude historical seismicity of the immediate area as well as the current regional stress regime based on a range of surface rupture lengths and depths to the base of the seismogenic zone we estimate a maximum earthquake magnitude m for the polaris fault to be between 6 4 and 6 9

displacement fields from point cloud data application of particle imaging velocimetry to landslide geodesy 1 acquiring spatially continuous ground surface displacement fields from terrestrial laser scanners tls will allow better understanding of the physical processes governing landslide motion at detailed spatial and temporal scales problems arise however when estimating continuous displacement fields from tls point clouds because reflecting points from sequential scans of moving ground are not defined uniquely thus repeat tls surveys typically do not track individual reflectors here we implemented the cross correlation based particle image velocimetry piv method to derive a surface deformation field using tls point cloud data we estimated associated errors using the shape of the cross correlation function and tested the method s performance with synthetic displacements applied to a tls point cloud we applied the method to the toe of the episodically active cleveland corral landslide in northern california using tls data acquired in june 2005 january 2007 and january may 2010 estimated displacements ranged from decimeters to several meters and they agreed well with independent measurements at better than 9 root mean squared rms error for each of the time periods the method provided a smooth nearly continuous displacement field that coincides with independently mapped boundaries of the slide and permits further kinematic and mechanical inference for the 2010 data set for instance the piv derived displacement field identified a diffuse zone of displacement that preceded by over a month the development of a new lateral shear zone additionally the upslope and downslope displacement gradients delineated by the dense piv field elucidated the non rigid behavior of the slide

structural analysis of coseismic normal fault zones of the 2011 mw 6 6 fukushima earthquake northeast japan the 2011 m w 6 6 fukushima earthquake occurred in iwaki city 250 km southwest of the epicenter of the 2011 m w 9 0 tohoku japan earthquake and produced two subparallel 15 23 km long surface rupture zones with distinct displacements along two pre existing normal faults the shionohira and yunodake faults which strike north northwest south southeast and northwest southeast both dipping southwest respectively field investigations and structural analysis of the coseismic shear zones developed within the shionohira and yunodake fault zones reveal that 1 the coseismic shear zones consist of a fault core that includes a narrow fault gouge zone of 10 cm in width generally 1 5 cm a fault breccia zone of 50 cm in width and a damage zone of 5 50 m in width that is composed of cataclastic rocks fractures and subsidiary faults 2 the foliations characterized by s c fabrics developed in the shear zones indicate a dominantly normal fault slip sense consistent with that observed along the coseismic surface ruptures and 3 veinlet cataclastic rocks composed of unconsolidated fault gouges and fine grained materials occur as simple discrete veinlets and multiple cross cutting interconnected networks of veinlets these newly documented structural characteristics for two coseismic fault shear zones and associated cataclastic rocks indicate that the locations of coseismic slip zones associated with the 2011 fukushima earthquake were controlled by pre existing fault shear zones central to the shionohira and yunodake faults which have repeatedly moved as seismogenic normal faults since the timing of formation of associated cataclastic rocks our results demonstrate that the structural analyses of coseismic shear fault zones provide a powerful tool to study the nature and active faulting history of seismological faults

the surface rupture and slip distribution of the 17 august 1999 izmit earthquake m 7 4 north anatolian fault the 17 august 1999 izmit earthquake occurred on the northern strand of the north anatolian fault zone the earthquake is associated with a 145 km long surface rupture that extends from southwest of duzce in the east to west of hersek delta in the west detailed mapping of the surface rupture shows that it consists of five segments separated by releasing step overs herein named the hersek karamursel golcuk izmit sapanca lake sapanca akyazi and karadere segments from west to east respectively the hersek segment which cuts the tip of a large delta plain in the western end of the rupture zone has an orientation of n80 the n70 80 e trending karamursel golcuk segment extends along the linear southern coasts of the izmit gulf between karamursel and golcuk and produced the 470 cm maximum displacement in golcuk the northwest southeast striking golcuk normal fault between the karamursel golcuk and izmit sapanca segments has 2 3 m maximum vertical displacement the maximum dextral offset along the izmit sapanca lake segment was measured to be about 3 5 m and its trend varies between n80 e and east west the sapanca akyazi segment trends n75 85 w and expresses a maximum displacement of 5 2 m the karadere segment trends n65 e and produced up to 1 5 m maximum displacement the karadere and sapanca akyazi segments form fan shape or splaying ruptures near their eastern ends where the displacement also diminished

measuring ground displacements from sar amplitude images application to the landers earthquake ers sar amplitude images are utilized to map ground displacements from a sub pixel correlation method it yields a ground two dimensional displacement field with independent measurements about every 128m in azimuth and 250m in range the accuracy depends on the characteristics of the images for the landers test case the 1 uncertainty is 0 8m in range and 0 4m in azimuth we show that this measurement provides a map of major surface fault ruptures accurate to better than 1km and information on coseismic deformation comparable to the 92 gps measurements available although less accurate this technique is more robust than sar interferometry and provides complementary information since interferograms are only sensitive to the displacement in range

rapid determination of near fault earthquake deformation using differential lidar improved near field measurements of earthquake slip and deformation patterns have the potential for expanding our understanding of fault behavior and the relationship of active faulting to topography current techniques for obtaining these measurements including field observation global navigation satellite systems displacement estimation and optical or radar remote sensing have limitations that can be mitigated by the inclusion of results from differential airborne light detection and ranging lidar analysis of the rupture zone the 2005 airborne lidar survey of the southern san andreas san jacinto and banning faults the b4 survey mapped 1100 km of the most seismically active fault systems in southern california for the purpose of providing a baseline for determining slip from a future earthquake we used the b4 survey to develop a processing algorithm that yields rapid estimates of near fault ground deformation using simultaneous cross correlation of both topography and backscatter intensity from pre earthquake and simulated postearthquake lidar datasets we show robust recovery of the direction and magnitude of an applied synthetic slip of 5 m in the horizontal and 0 5 m in the vertical within our area of study with clear discrimination between areas with and without applied slip we also successfully recovered more complex deformation from a modeled fault stepover in the same study area our results indicate that we should be able to recover slip to accuracies of better than 20 cm in the horizontal and 1 cm in the vertical at a spatial resolution of 15 m for lidar datasets with sample densities as low as 0 5 points m2

probing the mechanical properties of seismically active crust with space geodesy study of the coseismic deformation due to the 1992 mw7 3 landers southern california earthquake 1 the coseismic deformation due to the 1992 m w 7 3 landers earthquake southern california is investigated using synthetic aperture radar sar and global positioning system gps measurements the ers 1 satellite data from the ascending and descending orbits are used to generate contiguous maps of three orthogonal components east north up of the coseismic surface displacement field the coseismic displacement field exhibits symmetries with respect to the rupture plane that are suggestive of a linear relationship between stress and strain in the crust interferometric synthetic aperture radar insar data show small scale deformation on nearby faults of the eastern california shear zone some of these faults in particular the calico rodman and pinto mountain faults were also subsequently strained by the 1999 m w 7 1 hector mine earthquake i test the hypothesis that the anomalous fault strain represents essentially an elastic response of kilometer scale compliant fault zones to stressing by nearby earthquakes fialko et al 2002 the coseismic stress perturbations due to the landers earthquake are computed using a slip model derived from inversions of the insar and gps data calculations are performed for both homogeneous and transversely isotropic half space models the compliant zone model that best explains the deformation on the calico and pinto mountain faults due to the hector mine earthquake successfully predicts the coseismic displacements on these faults induced by the landers earthquake deformation on the calico and pinto mountain faults implies about a factor of 2 reduction in the effective shear modulus within the similar to 2 km wide fault zones the depth extent of the low rigidity zones is poorly constrained but is likely in excess of a few kilometers the same type of structure is able to explain high gradients in the radar line of sight displacements observed on other faults adjacent to the landers rupture in particular the lenwood fault north of the soggy lake has likely experienced a few centimeters of left lateral motion across 1 km wide compliant fault zone having the rigidity reduction of more than a factor of 2 the inferred compliant fault zones are interpreted to be a result of extensive damage due to past earthquakes

the displacement field of the landers earthquake mapped by radar interferometry geodetic data obtained by ground or space based techniques can be used to infer the distribution of slip on a fault that has ruptured in an earthquake although most geodetic techniques require a surveyed network to be in place before the earthquake1 3 satellite images when collected at regular intervals can capture co seismic displacements without advance knowledge of the earthquake s location synthetic aperture radar sar interferometry first introduced4 in 1974 for topographic mapping5 8 can also be used to detect changes in the ground surface by removing the signal from the topography9 10 here we use sar interferometry to capture the movements produced by the 1992 earthquake in landers california11 we construct an interferogram by combining topographic information with sar images obtained by the ers 1 satellite before and after the earthquake the observed changes in range from the ground surface to the satellite agree well with the slip measured in the field with the displacements measured by surveying and with the results of an elastic dislocation model as a geodetic tool the sar interferogram provides a denser spatial sampling 100 m per pixel than surveying methods1 3 and a better precision 3 cm than previous space imaging techniques12 13

surface fault ruptures and slip distributions of the mw 6 6 11 april 2011 hamadoori fukushima prefecture northeast japan earthquake the 11 april 2011 hamadoori fukushima prefecture northeast japan earthquake occurred in a seismically active area one month after the 11 march 2011 off the pacific coast of tohoku earthquake the hamadoori earthquake resulted in a 14 km long down to the west normal slip rupture on the north northwest south southeast striking itozawa fault as well as a 16 km long down to the south normal slip rupture on the west northwest east southeast striking yunodake fault the slip along the itozawa fault increases abruptly from the southern end to the central part of the fault where the measured maximum displacement is close to 2 m the slip decreases gradually from the central section to the northwestern end of the fault the yunodake fault also has an asymmetric slip distribution with a peak of about 0 9 m near the northwestern section of the fault considering the direction of rupture propagation along the two faults it is apparent that the measured surface offset is asymmetric along the strike with the largest offsets observed nearer the end of the fault where the rupture began and showing a gradual decrease in the direction of rupture termination the surface observations of the slip distribution and the epicenter location are consistent with the general features of earthquake ruptures derived from slip inversion models on more than 60 of the rupture length of the hamadoori earthquake faults as well as on other historic normal fault earthquakes slip displacements are less than or equal to 30 of the maximum slip the moment magnitude m w of the earthquake estimated from ruptures length maximum and average displacements is between 6 5 and 6 8 in accordance with the seismologically determined value of 6 6 online material supplementary data of the surface slip distributions of the 11 april 2011 hamadoori earthquake along the itozawa and yunodake faults

coseismic slip variation assessed from terrestrial lidar scans of the el mayor cucapah surface rupture abstract we analyze high resolution 103 points m2 terrestrial lidar surveys of the 4 april 2010 el mayor cucapah earthquake rupture baja california mexico collected at three sites 12 18 days after the event using point cloud based tools in an immersive visualization environment we quantify coseismic fault slip for hundreds of meters along strike and construct densely constrained along strike slip distributions from measurements of offset landforms uncertainty bounds for each offset determined empirically by repeatedly measuring offsets at each site sequentially illuminate measurement uncertainties that are difficult to quantify in the field these uncertainties are used to define length scales over which variability in slip distributions may be assumed to reflect either recognizable earthquake mechanisms or measurement noise at two sites characterized by 2 3 m of concentrated right oblique slip repeat measurements yield 2 uncertainties of 11 12 each site encompasses 200 m along strike and a smoothed linear slip gradient satisfies all measurement distributions implying along fault strains of 10 3 conversely the common practice of defining the slip curve by the local slip maxima distorts the curve overestimates along fault strain and may overestimate actual fault slip by favoring measurements with large positive uncertainties at a third site characterized by 1 2 5 m of diffuse normal slip repeat measurements of fault throw summed along fault perpendicular profiles yield 2 uncertainties of 17 here a low order polynomial fit through the measurement averages best approximates surface slip however independent measurements of off fault strain accommodated by hanging wall flexure suggest that over the 200 m length of this site a linear interpolation through the average values for the slip maxima at either end of this site most accurately represents subsurface displacement in aggregate these datasets show that given uncertainties of greater than 11 2 slip distributions over shorter scales are likely to be less uneven than those derived from a single set of field or lidar based measurements this suggests that the relatively smooth slip curves we obtain over 102 m distances reflect real physical phenomena whereas short wavelength variability over 100 101 m distances can be attributed to measurement uncertainty

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

structural analysis of the right lateral strike slip qingchuan fault northeastern segment of the longmen shan thrust belt central china abstract the eastern margin of the tibetan plateau is marked by the longmen shan thrust belt lstb which is dominated by thrust faults and thrust related fold structures that is home to the 2008 mw 7 9 thrusting type wenchuan earthquake although previous works demonstrated that the seismogenic fault for the earthquake changed coseismic slip sense from thrust dominated slip in the central and southeastern segments of the lstb to right lateral strike slip dominated displacement along the qingchuan fault northeastern segment of the lstb the related structures and current activity of the qingchuan fault remains unclear topographic analyses of 0 5 m resolution worldview imagery and digital elevation model dem data field investigations and structural analysis of the fault zone reveal that i stream channels and late pleistocene holocene terrace risers and alluvial fans are systematically offset dextrally along the qingchuan fault ii foliations developed in the fault zone indicate a right lateral strike slip dominated displacement and iii geological evidence and seismic data show that the qingchuan fault is currently active as the main seismogenic fault dominated by a right lateral strike slip with an average slip rate of ca 3 5 mm yr our results demonstrate that the spatial change in slip sense along the lstb from thrust dominated in the central and southwestern sectors to right lateral strike slip dominated in the northeastern sector is mainly caused by a change in the orientation of fault geometry from ne sw to ene wsw along the lstb

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

on and off fault deformation associated with the september 2013 mw 7 7 balochistan earthquake implications for geologic slip rate measurements abstract the 24 september 2013 mw7 7 balochistan pakistan earthquake ruptured a 200 km long stretch of the hoshab fault in southern pakistan and produced the second largest lateral surface displacement observed for a continental strike slip earthquake we remotely measured surface deformation associated with this event using high resolution 0 5 m pre and post event satellite optical imagery we document left lateral near field on fault offsets 10 m from fault using 309 laterally offset piercing points such as streams terrace risers and roads peak near field displacement is 13 6 2 5 3 4 m we characterize off fault deformation by measuring medium 350 m from fault displacement using manual 259 measurements and automated image cross correlation methods respectively off fault peak lateral displacement values are 15 m and exceed on fault displacement magnitudes for 85 of the rupture length our observations suggest that for this rupture coseismic surface displacement typically increases with distance away from the surface trace of the fault however nearly 100 of total surface displacement occurs within a few hundred meters of the primary fault trace furthermore off fault displacement accounts for on average 28 of the total displacement but exhibits a highly heterogeneous along strike pattern the best agreement between near field and far field displacements generally corresponds to the narrowest fault zone widths our analysis demonstrates significant and heterogeneous mismatches between on and off fault coseismic deformation and we conclude that this phenomenon should be considered in hazard models based on geologically determined on fault slip rates

some thoughts on measuring earthquake deformation using optical imagery optical imagery has been proven to be an effective tool for measuring earthquake deformation in continental regions since its first application in the 1999 izmit earthquake in this article we compile and analyze all the earthquakes that have been investigated with optical image matching by 2019 based on which we comment on various issues regarding measuring earthquake deformation with optical imagery new generations of very high resolution vhr data are effective for earthquake studies but orthorectification of the vhr images is the major source of error which is often ignored we found that the displacements derived from the worldview images strongly correlate with the errors in the shuttle radar topography mission srtm digital elevation model dem that was used in orthorectification based on the observed correlation between displacements and topography we propose a new dem based method using the advanced land observing satellite alos world 3 d dem to reduce the orthorectification errors combining the published optical data of earthquake deformation we re analyze the coseismic slip distribution and shallow slip deficit ssd the ssd model states that the coseismic slip in many strike slip earthquakes decreases in magnitude toward the surface but this model remains arguable because the interferometric synthetic aperture radar insar derived slip is usually not well constrained at shallow depths due to decorrelation because optical matching directly measures the surface slip we re examine the slip distribution of 11 strike slip earthquakes and find that the ssd model may primarily be artifacts in the insar measurements it is therefore of great importance to include the optical data in earthquake studies to constrain coseismic slip inversions

surface rupture and slip distribution of the 1940 imperial valley earthquake imperial fault southern california implications for rupture segmentation and dynamics we analyzed high resolution aerial photography taken soon after the 1940 imperial valley earthquake to provide a higher resolution distribution of displacement with which to test variation in lateral slip to compare the difference in making slip measurements parallel to local or regional fault strike and to compare to the seismo logical properties of the 1940 earthquake we performed 648 new measurements of displacement along the 15 km section of rupture for which imagery exists nearly 7 m of maximum displacement occurred within 2 km of the border which was higher than previous estimates with an average slip of about 5 5 m for this section there is considerable variation along the strike on the order of 1 m of variability across hundreds of meters of lateral distance in the section of high slip areas of larger offset tend to have greater variations in displacement from these observations we conclude that lateral variability of displacement typically varies by as much as 30 along a rupture section the difference in measured displacement at a specific point along the fault varied considerably when using local fault strikes versus that of regional or average fault however the overall average difference between measurements for different azimuths at a specific point is only 0 01 0 19 m indicating that this is not a major issue if one is consistent finally abrupt changes in displacement along a strike are apparently related to segmentation and the rupture process and mimic the subevents as documented through seismological methods the largest moment pulse corresponds to the section south of the border whereas the greatest displacements occurred north of the border where the average moment release is inferred to be less we explain this by inferring a strong shallow as perity in the border region consistent with 1979 rupture event beneath it online material high resolution imagery of the 1940 rupture with locations of offset measurements and tabulated offset values

simultaneous reactivation of two subparallel inland normal faults during the mw 6 6 11 april 2011 iwaki earthquake triggered by the mw 9 0 tohoku oki japan earthquake the gigantic m w 9 0 11 march 2011 tohoku oki earthquake suddenly changed the overriding inland area to an extensional stress regime and triggered massive seismic swarms in the coastal region the largest earthquake of m w 6 6 struck southern fukushima on 11 april 2011 and ruptured two previously mapped faults the northwest nw trending yunodake fault and the north northwest nnw trending itozawa fault clear 15 km long and 14 km long surface ruptures appeared along both faults respectively exhibiting a predominantly normal sense of slip down to the west the maximum vertical offset on the yunodake fault is 0 8 m whereas that on the itozawa fault is 2 1 m the itozawa fault rupture is in part marked by uphill facing scarps which is discordant with the large scale topography but consistent with saddled ridges and ponded alluvium the yunodake fault which bounds a neogene half graben structure juxtaposing mesozoic metamorphic rocks against neogene sedimentary rocks shows left lateral deflections of streams seismological data and interviews of local residents revealed that the two subparallel faults ruptured simultaneously based on the location of its hypocenter we however interpret that the itozawa rupture was primary and then triggered normal faulting on the yunodake fault under the heightened coulomb stress caused by the preceding tohoku oki earthquake our paleoseismic trench across the itozawa fault exposed evidence for a penultimate earthquake that occurred sometime between 12 620 and 17 410 cal yr b p there is no evidence that the itozawa fault ruptured during or immediately after the a d 869 jogan earthquake which is believed to be the penultimate giant megathrust earthquake along the japan trench

rupture process of the 2008 iwate miyagi nairiku japan earthquake derived from near source strong motion records abstract we derive the rupture process of the 2008 iwate miyagi nairiku japan earthquake m jma 7 2 during which the largest ground acceleration to date namely 4022 cm sec 2 was recorded at a hanging wall station iwth25 station of kik net just above the hypocenter velocity waveform data 0 1 1 hz at 14 strong motion stations of k net and kik net including the borehole records of iwth25 are inverted using the multi time window linear waveform inversion method we assume a horizontally layered velocity structure model having low velocity subsurface layers for each station in order to calculate the green s functions the waveform inversion indicates that there are two major slip patches one patch extends from the hypocenter to the southern shallower part of the fault a particularly large slip area in this patch is centered approximately 8 km to the south of the hypocenter with a maximum slip of 6 2 m the area ruptured between 4 and 9 sec after the initial break the other patch with smaller slip is located in the northern part which broke after the rupture of the southern slip patch the initial 0 4 sec rupture occurred beneath iwth25 contributing to the synthesis of a distinctive upward velocity pulse at this station examination of the slip contribution to the synthetic velocity waveforms and comparison of the isochrones with the slip distribution suggest that a peak acceleration greater than 4000 cm sec 2 observed at iwth25 was generated from the area that is closest to the hypocenter in the southern particularly large slip area

three dimensional surface displacements and rotations from differencing pre and post earthquake lidar point clouds 1 the recent explosion in sub meter resolution airborne lidar data raises the possibility of mapping detailed changes to earth s topography we present a new method that determines three dimensional 3 d coseismic surface displacements and rotations from differencing pre and post earthquake airborne lidar point clouds using the iterative closest point icp algorithm tested on simulated earthquake displacements added to real lidar data along the san andreas fault the method reproduces the input deformation for a grid size of 50 m with horizontal and vertical accuracies of 20 cm and 4 cm values that mimic errors in the original spot height measurements the technique also measures rotations directly resolving the detailed kinematics of distributed zones of faulting where block rotations are common by capturing near fault deformation in 3 d the method offers new constraints on shallow fault slip and rupture zone deformation in turn aiding research into fault zone rheology and long term earthquake repeatability

kinematic gps solutions for aircraft trajectories identifying and minimizing systematic height errors associated with atmospheric propagation delays 1 when kinematic gps processing software is used to estimate the trajectory of an aircraft unless the delays imposed on the gps signals by the atmosphere are either estimated or calibrated via external observations then vertical height errors of decimeters can occur this problem is clearly manifested when the aircraft is positioned against multiple base stations in areas of pronounced topography because the aircraft height solutions obtained using different base stations will tend to be mutually offset or biased in proportion to the elevation differences between the base stations when performing kinematic surveys in areas with significant topography it should be standard procedure to use multiple base stations and to separate them vertically to the maximum extent possible since it will then be much easier to detect mis modeling of the atmosphere

reevaluation of surface rupture parameters and faulting segmentation of the 2001 kunlunshan earthquake mw7 8 northern tibetan plateau china the 14 november 2001 m w 7 8 kunlunshan earthquake ruptured the westernmost part of the kunlun fault northern tibetan plateau the main segment affected by this event was the kusaihu segment field investigations allowed us to constrain the length the width and the coseismic horizontal displacement distribution of the kunlunshan earthquake rupture zone the mapped surface rupture zone starts from 90 257 e in the west and ends at 94 795 e in the east with a total length of 426 km it consists of three main sections the western strike slip section the transtensional section and the eastern strike slip section the rupture zone is oriented n100 10 e on average the distribution of the coseismic horizontal displacements is characterized by multiple peaks departing clearly from a general bell shaped distribution reassessment of the maximum coseismic horizontal left lateral displacement yields a value of 7 6 0 4 m at the site 35 767 n 93 323 e consistent with independent measurements derived from interferometric synthetic aperture radar and seismology from this site the horizontal displacement decreases unevenly to both the west and east coseismic vertical reverse displacement is also noted at the eastern end of the rupture but it remains much smaller than the horizontal component the width of the rupture zone varies from site to site from several meters to few kilometers the maximum width measured reaches 8 km along the yuxi feng subsection where a large number of shaking related cracks were well developed

slip in the 2010 2011 canterbury earthquakes new zealand the 3rd september 2010 mw 7 1 darfield and 21st february 2011 mw 6 3 christchurch new zealand earthquakes occurred on previously unknown faults we use insar ground displacements sar amplitude offsets field mapping aerial photographs satellite optical imagery a lidar dem and teleseismic body wave modeling to constrain the pattern of faulting in these earthquakes the insar measurements reveal slip on multiple strike slip segments and secondary reverse faults associated with the darfield main shock fault orientations are consistent with those expected from the gps derived strain field the insar line of sight displacement field indicates the main fault rupture is about 45 km long and is confined largely to the upper 10 km of the crust slip on the individual fault segments of up to 8 m at 4 km depth indicate stress drops of 6 10 mpa in each event rupture initiated on a reverse fault segment before continuing onto a strike slip segment the non double couple seismological moment tensors for each event are matched well by the sum of double couple equivalent moment tensors for fault slip determined by insar the slip distributions derived from insar observations of both the darfield and christchurch events show a 15 km long gap in fault slip south west of christchurch which may present a continuing seismic hazard if a further unknown fault structure of significant size should exist there

locating distributed faulting contributions from insar imaging to probabilistic fault displacement hazard analysis pfdha abstract prediction of location and amount of slip for distributed faulting associated to strong earthquakes is a recently explored issue with major implications in terms of hazard assessment currently the best practice involves the applications of probabilistic fault displacement hazard analysis pfdha whose results fit sufficiently well real data in the near range of the primary fault but show considerable inaccuracies in the far range we believe that this inaccuracy descends from the biased earthquake databases used for regression analysis whose data relative to old earthquakes were largely collected only by field surveys focused close to the primary fault i e near range remotely sensed data i e interferometric radar imaging insar offer the opportunity to precisely measure the surface deformation induced by strong earthquakes and thus to explore its possible relation with distributed faulting we analyze the l aquila earthquake case study 29th april 2009 mw 6 3 and explore the correlation between location and slip on distributed faulting and insar derived deformation field we find a significant correlation between occurrence of distributed faulting and profile curvature of the dislocation field in spite of the distance from the primary fault moreover distributed faults tend to occur within the area deformed by the earthquake as imaged by insar data and whose extent is directly proportional to the earthquake magnitude mw according to a dataset of 30 recent earthquakes we then propose that these observations have to be incorporated into the present pfdha practice as limit boundaries to possible scenarios of probabilistic analysis and that an integrated use of field based and remotely data collection have to be implemented following strong earthquakes

how well do surface slip measurements track slip at depth in large strike slip earthquakes the importance of fault structural maturity in controlling on fault slip versus off fault surface deformation abstract comparisons of observed surface displacements with geodetically inferred slip at depth in six large m w 7 1 strike slip earthquakes reveal a correlation between the structural maturity of the fault and the ratio of deep slip to surface slip that occurs on localized zones of surface rupture specifically structurally immature faults 25 km of total displacement manifest only 50 60 of total slip on narrow fault surface traces versus 85 95 for structurally mature faults 85 km total slip the same pattern holds when structurally simple parts of a surface rupture are analyzed separately from parts that exhibit obvious structural complexity e g discontinuous or multiple traces or significant dip slip these results imply that geologic measurements of surface slip along structurally immature faults are likely to significantly underestimate the true slip at depth in large earthquakes this observation has implications for a number of important problems including determination of fault slip rates which are based on surface offsets earthquake probability assessments which are based on geologic fault slip rates comparisons of geologic and geodetic rate data in the search for strain transients the structural evolution of fault zones estimation of paleo earthquake magnitudes based on geomorphic offsets analyses of the relative importance of faulting vs distributed deformation in accommodating relative plate motions in continental crust the design and construction of infrastructure built near active faults and possibly for the prediction of strong ground motions which may at least partially depend on the degree of slip localization to the surface

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

nonplanar fault source modeling of the 2008 mw 6 9 iwate miyagi inland earthquake in northeast japan we use crustal deformation data sets acquired by the phased array type l band synthetic aperture radar palsar and the japanese nationwide global positioning system gps earth observation network geonet to develop a fault source model for the 2008 iwate miyagi inland earthquake m w 6 9 that occurred on 14 june 2008 in northeastern honshu japan the palsar data include interferometric synthetic aperture radar insar range offset and azimuth offset acquired from both ascending and descending paths the range and azimuth offset data are the only quantitative deformation signals around the epicenter and exhibit complicated signals that were not detected by the gps data we refine our preliminary model by using green s functions from triangular dislocation elements to represent nonplanar fault geometries although a single segment model can well explain the gps data it generates significant misfit residuals in the offset data thus both west dipping and east dipping segments are necessary as also suggested from aftershock distribution data the moment magnitudes of the west dipping and east dipping faults are 6 53 and 6 76 respectively and the total sum 6 87 is almost identical to the seismological moment magnitude this result suggests that both segments contributed equally to the total seismic moment demonstrating a complex rupture process of the inland earthquake

lateral offsets on surveyed cultural features resulting from the 1999 izmit and duzce earthquakes turkey surveys of offset linear cultural features that cross the surface ruptures of the 17 august and 12 november 1999 earthquakes on the north anatolian fault in turkey yield slip values as large as or larger than those recorded by near field measurements in the same areas immediately after the earthquake using long linear alignments of trees fence lines walls and canals we demonstrate as much as a 2 m increase in observed slip over the initial field measurements on an average we observed about 15 of the total lateral slip as off fault deformation with values ranging from 0 to 40 of the total slip part of this lateral deformation is accom modated by bending or drag in a zone as much as 30 m in width although usually the zone varies between 5 and 20 m in width this supports the idea that substantial nonbrittle off fault deformation is associated with ruptures in areas of alluvial fill alternatively there may have been substantial afterslip although none has been recognized on postearthquake repaired structures our observations suggest that post earthquake measurements of fault slip using tape measures on offset geomorphic features may underestimate the actual amount of slip in that event where the non linearity of the offset feature does not allow recognition of the warping surveys of multiple tree lines within groves of poplar trees planted in straight lines across the fault prior to the earthquake show surprisingly large lateral varia tions in one grove slip increases by nearly 1 8 m or 35 of the maximum measured value over a lateral distance of nearly 100 m this and other observations along the 1999 ruptures suggest that the lateral variability of slip observed from displaced geomorphic features in many earthquakes of the past may represent a combination of 1 actual differences in slip at the surface and 2 the difficulty in recognizing distributed nonbrittle deformation

complex ruptures of the 11 april 2011 mw 6 6 iwaki earthquake triggered by the 11 march 2011 mw 9 0 tohoku earthquake japan abstract after the 11 march 2011 m w 9 0 tohoku earthquake japan a swarm of shallow normal faulting earthquakes was triggered in a localized region beneath the border between fukushima and ibaraki prefectures in eastern honshu here we examine the coseismic displacement field and a fault model of the largest event of the swarm the 11 april 2011 m w 6 6 iwaki earthquake radar interferometry applied to data of the japanese alos satellite reveals complex ruptures associated with the iwaki earthquake in particular the interferogram clearly shows multiple surface ruptures along each of the subparallel yunodake and itozawa faults the slip distributions on these faults as estimated by inverting the interferogram suggest that the faults dip 60 70 westward and that slip on the itozawa fault extended to a splay fault at depths shallower than about 5 km our results indicate that the highland area west of the itozawa fault was downthrown by up to 2 4 m during the iwaki earthquake online material original and de trended interferograms over a wider area

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

surficial slip distribution on the central emerson fault during the june 28 1992 landers earthquake california we present the results of our mapping of a 5 6 km length of the central emerson fault that ruptured during the 1992 landers earthquake in the southwestern mojave desert california the right lateral slip along this portion of the rupture varied from about 150 to 530 cm along the main rupture zone in some locations a total of up to 110 cm of additional right lateral slip occurred on secondary faults up to 1 7 km away from the main rupture zone other secondary faults carried up to several tens of centimeters of left lateral or thrust displacement the maximum net vertical displacement was 175 cm east side up the sense of vertical slip across the main fault zone varied along strike but in most cases it was consistent with the sense of vertical slip in previous earthquakes as indicated by the locations of areas of older uplifted and abandoned alluvial fan surfaces although variations in surficial slip have been reported along previous strike slip ruptures our closely spaced slip measurements allow a much more detailed study of slip variability than was possible previously we document variations in slip as large as 1 m or more over distances ranging from 1 2 km to a few tens of meters suggesting that strains of the order of 10 1 may have occurred locally within the surficial sediments the long wavelength kilometer scale variations in surficial slip may be influenced by fault geometry and perhaps by the thickness of unconsolidated sediments the slip variations over shorter length scales tens of meters may be caused by variations in the proportion of the total shear that occurs on visible brittle fractures versus that which occurs as distributed shear warping or rotation the variability of slip along the ruptures associated with the landers earthquake calls for caution in interpreting geomorphic offsets along prehistoric fault ruptures

on the relation between transform fault resistance and plate motion a simple model for power dissipation due to friction along transform faults is used to examine the relations between relative velocity and power dissipation across transforms transform lengths and plate motions comparison is made between ridge transforms i e those that are part of spreading systems and major boundary transforms such as the san andreas fault power dissipation is calculated using velocity across the transform area above the 400 c oceanic or 350 c continental isotherm transform thermal structure is modeled by averaging the temperatures on either side of the transform whereas ridge transforms across which the relative plate velocity is slow can be of any length fast relative velocities only appear across short transforms when all transforms are used in this comparison a maximum speed as a function of transform length is suggested a minimum speed of 13 5 mm yr across ridge transforms was found in a case study of the pacific plate the transform lengths were found to have varied with time which has minimized the total power dissipation across the plate s transforms

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

co registration of lunar topographic models derived from chang e 1 selene and lro laser altimeter data based on a novel surface matchingmethod abstract various lunar digital topographic models dtms have been generated from the data collected from earlier and recent lunar missions there are usually inconsistencies among them due to differences in sensor configurations data acquisition periods and production techniques to obtain maximum value for science and exploration the multi source lunar topographic datasets must be co registered in a common reference frame only such an effort will ensure the proper calibration registration and analysis of the datasets which in turn will permit the full comparative and synergistic use of them this study presents a multi feature based surface matching method for the co registration of multiple lunar dtms that incorporates feature points lines and surface patches in surface matching to guarantee robust surface correspondence a combined adjustment model is developed for the determination of seven transformation parameters one scale factor three rotations and three translations from which the multiple dtms could be co registered the lunar dtms derived from the chang e 1 selene and lro laser altimeter data in the apollo 15 landing area and the sinus iridum area are examined in this study small offsets were found among the chang e 1 selene and lro dtms through experimental analysis the developed multi feature based method was proven able to effectively co register multiple lunar dtms the performances of the multi feature based surface matching method were compared with the point based method and the former was proven to be superior to the latter

ability of 1 hz gps data to infer the source process of a medium sized earthquake the case of the 2008 iwate miyagi nairiku japan earthquake 1 we demonstrate the ability of 1 hz global positioning system gps data to infer a medium sized m6 class earthquake source process through an inversion study of the 2008 iwate miyagi nairiku japan earthquake m 6 9 1 hz gps waveforms for this earthquake are compared and show good agreement with strong motion waveforms ground motions are well recorded at a sufficient number of gps stations in and around source region allowing us to perform waveform inversion using 1 hz gps data only the 1 hz gps inversion result shows fairly good agreement with a joint inversion of geodetic and strong motion data such as the seismic moment mw 6 9 cumulative slip distribution and rupture propagation such agreements demonstrate that 1 hz gps is able to infer the dynamic features of the rupture process as well as permanent or static slip even for a m6 class medium sized earthquake

radar interferogram filtering for geophysical applications the use of sar interferometry is often impeded by decorrelation from thermal noise temporal change and baseline geometry power spectra of interferograms are typically the sum of a narrow band component combined with broad band noise we describe a new adaptive filtering algorithm that dramatically lowers phase noise improving both measurement accuracy and phase unwrapping while demonstrating graceful degradation in regions of pure noise the performance of the filter is demonstrated with sar data from the ers satellites over the jakobshavns glacier of greenland

an assessment of surface matching for the automated co registration of mola hrsc and hirise dtms abstract martian topographic data has been collected by various exploration missions over the last decade these products provide detailed topographic information and are invaluable for scientists to interpret and understand the geological and climate evolution which has occurred on mars in order to fully utilise these multi sensor multi resolution and multi scale martian topographic products a co registration process has been developed which allows co registration of digital terrain models dtms to be performed to co align these multiple datasets surface matching is the core technique to implement this task and it is here assessed to determine the parameters of the most robust algorithm for dtm co registration once this task was finished the matching tool was developed accordingly with a decision algorithm this algorithm was then employed to align dtms derived from mars orbiter laser altimeter mola high resolution stereo camera hrsc and high resolution imaging science experiment hirise for mola and hrsc dtms the co registration was performed directly as the mola dtm acted as a reference surface within a bundle adjustment process dtms from different versions covering three hrsc orbital strips were used for the assessment process as a result the mean bias of the height differences of a preliminary version hrsc dtm was significantly reduced from 38 596 m to 2 233 m when compared against mola while the bias of a newer dtm was improved from 1 616 m to 0 161 m after matching regarding the co registration of hirise and mola dtms a hierarchical approach employing a hrsc dtm as an intermediate dataset was assessed the results demonstrated that the method is feasible and that the three dtms were co registered effectively due to the success highlighted in this paper a surface matching tool is recommended to be applied to dtms derived from multiple sources before these data are further used moreover surface matching can be considered as an additional step of any workflow for mars dtm creation

optimization of legacy lidar data sets for measuring near field earthquake displacements airborne lidar light detection and ranging topography acquired before and after an earthquake can provide an estimate of the coseismic surface displacement field by differencing the preevent and postevent lidar point clouds however estimated displacements can be contaminated by the presence of large systematic errors in either of the point clouds we present three dimensional displacements obtained by differencing airborne lidar point clouds collected before and after the el mayor cucapah earthquake a mw 7 2 earthquake that occurred in 2010 the original surface displacement estimates contained large periodic artifacts caused by systematic errors in the preevent lidar data reprocessing the preevent data detailed herein removed a majority of these systematic errors that were largely due to misalignment between the scanning mirror and the outgoing laser beam the methodology presented can be applied to other legacy airborne laser scanning data sets in order to improve change estimates from temporally spaced lidar acquisitions

coseismic deformation from the 1999 mw 7 1 hector mine california earthquake as inferred from insar and gps observations we use interferometric synthetic aperture radar insar and global positioning system gps observations to investigate static deformation due to the 1999 m w 7 1 hector mine earthquake that occurred in the eastern california shear zone interferometric decorrelation phase and azimuth offset measurements indicate regions of surface and near surface slip which we use to constrain the geometry of surface rupture the inferred geometry is spatially complex with multiple strands the southern third of the rupture zone consists of three subparallel segments extending about 20 km in length in a n45 w direction the central segment is the simplest with a single strand crossing the bullion mountains and a strike of n10 w the northern third of the rupture zone is characterized by multiple splays with directions subparallel to strikes in the southern and central the average strike for the entire rupture is about n30 w the interferograms indicate significant along strike variations in strain which are consistent with variations in the ground based slip measurements using a variable resolution data sampling routine to reduce the computational burden we invert the insar and gps data for the fault geometry and distribution of slip we compare results from assuming an elastic half space and a layered elastic space results from these two elastic models are similar although the layered space model predicts more slip at depth than does the half space model the layered model predicts a maximum coseismic slip of more than 5 m at a depth of 3 to 6 km contrary to preliminary reports the northern part of the hector mine rupture accommodates the maximum slip our model predictions for the surface fault offset and total seismic moment agree with both field mapping results and recent seismic models the inferred shallow slip deficit is enigmatic and may suggest that distributed inelastic yielding occurred in the uppermost few kilometers of the crust during or soon after the earthquake

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

late quaternary and coseismic crustal deformation across the focal area of the 2008 iwate miyagi nairiku earthquake abstract we investigated late quaternary and coseismic crustal deformation rates in the 2008 iwate miyagi nairiku earthquake 2008 imeq focal area we identified five fluvial terraces and used tephrochronology and 14c dating to correlate them with marine isotope stages miss 6 5 slightly younger than 5 3 5 2 4 5 2 1 and 1 the late quaternary uplift rates calculated from the relative heights of the mis 6 5 120 140 ka and 2 1 10 ka terrace surfaces were 0 18 0 21 0 13 m ky and 0 62 0 74 0 13 m ky on the downthrown and upthrown sides of the 2008 imeq fault respectively we developed a fault model that reflected the coseismic vertical displacements and surface ruptures this model had a fault plane dipping to the west at 40 with slip of 4 4 m on the deep 10 3 km depth part of the fault plane and of 0 3 m on the shallow 3 0 km depth part the late quaternary and coseismic deformation pattern of the ground surface roughly agree furthermore the recurrence interval 2 9 4 2 ky calculated from the late quaternary vertical offset and coseismic vertical deformation roughly agrees with the findings of a previous trenching study thus the slip on the fault of the 2008 imeq was a characteristic earthquake event