persistent scatterer interferometric synthetic aperture radar for crustal deformation analysis with application to volcan alcedo galapagos 1 while conventional interferometric synthetic aperture radar insar is a very effective technique for measuring crustal deformation almost any interferogram includes large areas where the signals decorrelate and no measurement is possible persistent scatterer ps insar overcomes the decorrelation problem by identifying resolution elements whose echo is dominated by a single scatterer in a series of interferograms existing ps methods have been very successful in analysis of urban areas where stable angular structures produce efficient reflectors that dominate background scattering however man made structures are absent from most of the earth s surface furthermore existing methods identify ps pixels based on the similarity of their phase history to an assumed model for how deformation varies with time whereas characterizing the temporal pattern of deformation is commonly one of the aims of any deformation study we describe here a method for ps analysis stamps that uses spatial correlation of interferogram phase to find pixels with low phase variance in all terrains with or without buildings prior knowledge of temporal variations in the deformation rate is not required for their identification we apply stamps to volcan alcedo where conventional insar fails because of dense vegetation on the upper volcano flanks that causes most pixels to decorrelate with time we detect two sources of deformation the first we model as a contracting pipe like body which we interpret to be a crystallizing magma chamber the second is downward and lateral motion on the inner slopes of the caldera which we interpret as landsliding

resolving three dimensional surface displacements from insar measurements a review abstract one dimensional measurement along the line of sight los direction has greatly limited the capability of insar technique in the investigation of surface displacements and their dynamics in recent years great efforts have been made to resolve complete three dimensional 3 d displacements from insar measurements this contribution is intended to provide a systematic review of the progress achieved in this field based on an analysis of the insar los measurements we first cover two commonly used techniques i e offset tracking and multi aperture insar mai with which the surface displacement in the azimuth direction can be measured together with the los displacement several methods for mapping 3 d displacements using insar measurements are subsequently presented and categorized into three groups i combination of multi pass los and azimuth measurements ii integration of insar and gps data and iii prior information assisted approaches the strengths and weaknesses of each method are analyzed to show the applicability of each method to specific 3 d displacement mapping cases in hope to provide a useful guidance in choosing a suitable approach accordingly finally suggestions for resolving the challenging issues and outlook of future research are given

source parameters of the 2014 mw 6 1 south napa earthquake estimated from the sentinel 1a cosmo skymed and gps data abstract using the combination of two insar and one gps data sets we present the detailed source model of the 2014 mw 6 1 south napa earthquake the biggest tremor to hit the san francisco bay area since the 1989 mw 6 9 loma prieta earthquake the insar data are from the sentinel 1a s1a and cosmo skymed cs satellites and gps data are provided by nevada geodetic laboratory we firstly obtain the complete coseismic deformation fields of this event and estimate the insar data errors then using the s1a data to construct the fault geometry one main and two short parallel sub faults which haven t been identified by field investigation as expected the geometry is in good agreement with the aftershock distribution by inverting the insar and gps data we derive a three segment slip and rake models our model indicates that this event was a right lateral strike slip earthquake with a slight reverse component in the west napa fault as we estimated the fault is 30 km long and more than 80 of the seismic moment was released at the center of the fault segment where the slip reached its maximum up to 1 m we also find that our geodetic moment magnitude is 2 07 1018 nm corresponding to mw 6 18 larger than that of usgs mw 6 0 and gcmt mw 6 1 this difference may partly be explained by our insar data including about one week s postseismic deformation and aftershocks the results also demonstrate high snr and great ability of the newly launched sentinel 1a in earthquake study furthermore this study suggests that this earthquake has potential to trigger nearby faults especially the green valley fault where the coulomb stress was imparted by the 2014 south napa earthquake

early and persistent supershear rupture of the 2018 magnitude 7 5 palu earthquake the speed at which an earthquake rupture propagates affects its energy balance and ground shaking impact dynamic models of supershear earthquakes which are faster than the speed of shear waves often start at subshear speed and later run faster than eshelby s speed here we present robust evidence of an early and persistent supershear rupture at the sub eshelby speed of the 2018 magnitude 7 5 palu indonesia earthquake slowness enhanced back projection of teleseismic data provides a sharp image of the rupture process along a path consistent with the surface rupture trace inferred by subpixel correlation of synthetic aperture radar and satellite optical images the rupture propagated at a sustained velocity of 4 1 km s 1 from its initiation to its end despite large fault bends the persistent supershear speed is further validated by seismological evidence of far field rayleigh mach waves the unusual features of this earthquake probe the connections between the rupture dynamics and fault structure an early supershear transition could be promoted by fault roughness near the hypocentre steady rupture propagation at a speed unexpected in homogeneous media could result from the presence of a low velocity damaged fault zone

geodetic observations of the 2018 mw 7 5 sulawesi earthquake and its implications for the kinematics of the palu fault

interferogram formation in the presence of complex and large deformation 1 sierra negra volcano in isabela island galapagos erupted from october 22 to october 30 in 2005 during the 8 days of eruption the center of sierra negra s caldera subsided about 5 4 meters three hours prior to the onset of the eruption an earthquake mw 5 4 occurred near the caldera because of the large and complex phase gradient due to the huge subsidence and the earthquake it is difficult to form an interferogram inside the caldera that spans the eruption the deformation is so large and spatially variable that the approximations used in existing insar software roi roi pac doris gamma cannot properly coregister sar image pairs spanning the eruption we have developed here a two step algorithm that can form intra caldera interferograms from these data the first step involves a rubber sheeting sar image coregistration in the second step we use range offset estimates to mitigate the steep phase gradient using this new algorithm we retrieve an interferogram with the best coverage to date inside the caldera of sierra negra

monitoring landslides and tectonic motions with the permanent scatterers technique spaceborne differential synthetic aperture radar interferometry dinsar has already proven its potential for mapping ground deformation phenomena e g volcano dynamics however atmospheric disturbances as well as phase decorrelation have prevented hitherto this technique from achieving full operational capability these drawbacks are overcome by carrying out measurements on a subset of image pixels corresponding to pointwise stable reflectors permanent scatterers ps and exploiting long temporal series of interferometric data results obtained by processing 55 images acquired by the european space agency esa ers sar sensors over southern california show that the ps approach pushes measurement accuracy very close to its theoretical limit about 1 mm allowing the description of millimetric deformation phenomena occurring in a complex fault system a comparison with corresponding displacement time series relative to permanent gps stations of the southern california integrated gps network scign is carried out moreover the pixel by pixel character of the ps analysis allows the exploitation of individual phase stable radar targets in low coherence areas this makes spaceborne interferometric measurements possible in vegetated areas as long as a sufficient spatial density of individual isolated man made structures or exposed rocks is available the evolution of the ancona landslide central italy was analysed by processing 61 ers images acquired in the time span between june 1992 and december 2000 the results have been compared with deformation values detected during optical levelling campaigns ordered by the municipality of ancona the characteristics of ps gps and optical levelling surveying are to some extent complementary a synergistic use of the three techniques could strongly enhance quality and reliability of ground deformation monitoring d 2002 elsevier science b v all rights reserved

a new functional model for determining minimum and maximum detectable deformation gradient resolved by satellite radar interferometry in this paper a functional model for determining the minimum and maximum detectable deformation gradient in terms of coherence for synthetic aperture radar sar sensors is presented the model is developed based on a new methodology that incorporates both real and simulated data sets of representative surface deformation models have been simulated and the associated phase from these models introduced into real sar data acquired by european remote sensing 1 and 2 satellites subsequently interferograms were derived and surface deformation was estimated a number of cases of surface deformation with varying magnitudes and spatial extent have been simulated in each case the resultant surface deformation has been compared with the true surface deformation as defined by the deformation model based on these comparisons a set of observations that lead to a new functional model has been established finally the proposed model has been validated against external datasets and proven viable although the major weakness of the model is its reliance on visual interpretation of interferograms this model can serve as a decision support tool to determine whether or not to apply satellite radar interferometry to study a given surface deformation

constraints on surface deformation in the seattle wa urban corridor from satellite radar interferometry time series analysis summary we apply differential insar dinsar time series techniques to the urban corridor between tacoma seattle and everett wa using 93 interferograms from three satellites ers 1 ers 2 and radarsat 1 between 1992 and 2007 our goal is to study local tectonic geomorphic and groundwater processes consequently we remove long wavelength 50 100 km deformation signals from unwrapped interferograms by comparing surface velocities generated via the time series technique at more than two million points within the overlapping region between two independent ers tracks we estimate the uncertainty of relative surface velocity measurements to be 0 5 mm yr 1 in the vertical we estimate the uncertainty of relative displacement measurements to be 5 4 mm given our comparisons of dinsar derived time series to gps data a result that is consistent both with previous dinsar time series analysis and with the uncertainty expected from gps displacements projected onto the radar line of sight active tectonic deformation at shallow depths on the region s numerous east west structures is absent over the 11 5 yr of sar data examined assuming that the south dipping thrust beneath seattle and tacoma takes up 3 mm yr 1 of north south shortening our data indicate that the fault must be currently locked to a depth of greater than 10 km we also document extensive groundwater related deformation throughout much of the study region most notably we identify sharp linear deformation gradients near federal way wa and running between sumner wa and steilacoom wa these features may mark the locations of previously unmapped fault splays that locally control groundwater movement we find no slow landslide deformation on any of the numerous mapped slide complexes within seattle although regions of known active landsliding such as along perkins lane in seattle exhibit radar phase de correlation these observations are consistent with relatively infrequent and rapid landslide deformation within seattle

nine years of spatial and temporal evolution of the la valette landslide observed by sar interferometry abstract the la valette landslide located in the ubaye valley southern french alps has been investigated using 15 differential interferograms realized from ers 1 and ers 2 satellite radar images acquired between 1991 and 1999 both in 3 day cycle and tandem phase displacement values of the landslide have been deduced from the synthetic apenture radan sar interferometric products interpretation and compared with ground laser measurements four domains characterized by different velocity fields have been detected three of them can be distinguished from aerial photographs and field analysis the slow velocity of a resistant bar located in the eastern side of the landslide has been detected on sar interferograms between 1991 and 1996 changes in the landslide limits have been observed both in the upper and in the lower part the changes have been caused by a retrogression of the main scarp and a down slope progression of the main body of the landslide respectively the average daily velocity of the landslide between 1991 and 1999 derived by interferometric analysis decreased from 1 to 0 4 cm day in agreement with ground based measurements a peak velocity of around 2 cm day was observed in 1996

new paleomagnetic constraints on the cenozoic tectonic evolution of the north arm of sulawesi indonesia abstract extensive paleomagnetic sampling 34 sites was carried out in cenozoic formations of the north arm of sulawesi between 120 and 124 e consistent results obtained between 120 and 122 e suggest the existence of a unique post miocene clockwise rotation of about 20 25 of the western part of the north arm this rotation probably occurred during the northward drift of the north arm along the palu matano sinistral transcurrent fault between 122 5 and 124 e both clockwise and counterclockwise rotations with various amplitudes from 6 to 85 are encountered and these very likely correspond to individual microblock rotations due to pervasive deformation along shear zones this result is consistent with the complex fault system of the gorontalo and kotamobagu shear zones that have been recognized on radar imagery and by spot image analyses

new empirical relationships among magnitude rupture length rupture width rupture area and surface displacement source parameters for historical earthquakes worldwide are compiled to develop a series of empirical relationships among moment magnitude m surface rupture length subsurface rupture length downdip rupture width rupture area and maximum and average displacement per event the resulting data base is a significant update of previous compilations and includes the additional source parameters of seismic moment moment magnitude subsurface rupture length downdip rupture width and average surface displacement each source parameter is classified as reliable or unreliable based on our evaluation of the accuracy of individual values only the reliable source parameters are used in the final analyses in comparing source parameters we note the following trends 1 generally the length of rupture at the surface is equal to 75 of the subsurface rupture length however the ratio of surface rupture length to subsurface rupture length increases with magnitude 2 the average surface displacement per event is about one half the maximum surface displacement per event and 3 the average subsurface displacement on the fault plane is less than the maximum surface displacement but more than the average surface displacement thus for most earthquakes in this data base slip on the fault plane at seismogenic depths is manifested by similar displacements at the surface log linear regressions between earthquake magnitude and surface rupture length subsurface rupture length and rupture area are especially well correlated showing standard deviations of 0 25 to 0 35 magnitude units most relationships are not statistically different at a 95 significance level as a function of the style of faulting thus we consider the regressions for all slip types to be appropriate for most applications regressions between magnitude and displacement magnitude and rupture width and between displacement and rupture length are less well correlated and have larger standard deviation than regressions between magnitude and length or area the large number of data points in most of these regressions and their statistical stability suggest that they are unlikely to change significantly in response to additional data separating the data according to extensional and compressional tectonic environments neither provides statistically different results nor improves the statistical significance of the regressions regressions for cases in which earthquake magnitude is either the independent or the dependent parameter can be used to estimate maximum earthquake magnitudes both for surface faults and for subsurface seismic sources such as blind faults and to estimate the expected surface displacement along a fault for a given size earthquake

fission track and fault kinematics analyses for new insight into the late cenozoic tectonic regime changes in west central sulawesi indonesia abstract the left lateral strike slip central sulawesi fault system csfs composed of the nnw palu koro pkf and the ese matano faults is located within the eastern indonesian triple junction between the pacific indo australian and eurasian plates fault kinematic and fission track analyses show that the late cenozoic central sulawesi deformation results from three successive tectonic regimes 1 a late miocene early pliocene 5 ma wnw trending shortening characterized by transpressional deformation along the pkf and compressional in the poso area this tectonics resulted from the collision between the banggai sula block with sulawesi it produced locally a transpressional regime as a consequence of the northward extrusion of the central sulawesi block limited by the pkf 2 a pliocene collapse tectonic regime associated with w trending extension coeval with these events regional cooling and exhumation took place 3 a quaternary transtensional regime resulting from the combined effects of the central sulawesi block northward motion and extension related to back arc spreading behind the north sulawesi subduction tomini gulf

interferometric synthetic aperture radar insar atmospheric correction gps moderate resolution imaging spectroradiometer modis and insar integration atmospheric effects represent one of the major limitations of repeat pass interferometric synthetic aperture radar insar in this paper gps and moderate resolution imaging spectroradiometer modis data were integrated to provide regional water vapor fields with a spatial resolution of 1 km 1 km and a water vapor correction model based on the resultant water vapor fields was successfully incorporated into the jet propulsion laboratory california institute of technology roi pac software the advantage of this integration approach is that only one continuous gps station is required within a 2030 km 1354 km modis scene application to ers 2 repeat pass data over the los angeles southern california integrated gps network scign area shows that this integration approach not only helps discriminate geophysical signals from atmospheric artifacts but also reduces water vapor effects significantly which is of great interest to a wide community of geophysicists

rapid cooling and exhumation as a consequence of extension and crustal thinning inferences from the late miocene to pliocene palu metamorphic complex sulawesi indonesia abstract metamorphic complexes forming high mountains of 1 5 2 km in western sulawesi were previously considered to be mesozoic or older basement of gondwana crust however many of the metamorphic rocks are much younger than previously thought some have eocene sedimentary protoliths new geothermobarometric and geochronological data from metamorphic rocks of the palu metamorphic complex pmc and associated granitoids provide information on the timing and mechanisms of neogene metamorphism and contemporaneous rapid exhumation the metamorphic rocks are strongly deformed and some were partially melted to form migmatites schists contain relict andalusite cordierite staurolite and mn rich garnet which are wrapped by a pervasive fabric 40ar 39ar dating of biotite white mica and amphibole from strongly deformed mylonitic schists and recrystallised amphibolites reveals cooling occurred in the early pliocene c 5 3 4 8 ma in the northern part and during the late pliocene c 3 1 2 7 ma in the southern part of the pmc u pb 40ar 39ar and u th he analyses of various minerals from pmc metamorphic and s type magmatic rocks give very similar mid to late pliocene ages indicating very fast cooling and rapid exhumation and show the high speed at which tectonic processes including magmatism exhumation and reworking into a sediment must have occurred the high rates could be unique to this area but we suggest they record the true speed of metamorphic complex exhumation in a very young orogenic belt rates in older orogens appear lower because they are averages measured over longer periods of time contemporaneous magmatism and deformation are interpreted as a consequence of decompressional melting due to extension and thinning of the crust promoted by possible detachment faults and normal faulting at the major nw trending palu koro and tambarana faults in contrast i type magmatic rocks separated from the pmc by the palu koro fault were exhumed from upper crustal levels by erosion at moderate rates

development of pull apart basins a comparative study of well mapped active and ancient pull apart basins suggests a qualitative model for their continuous development pull aparts evolve from incipient to extremely developed basins through a sequence of closely related states new and compiled map data from several areas including the northern caribbean and turkey suggests the following stages in pull apart development 1 in rigid intracontinental strike slip plate boundary zones larger pull aparts nucleate at releasing fault bends along segments of the principal displacement strike slip fault zone which are oblique to the theoretical interplate slip lines 2 initial opening across releasing fault bends produces spindle shaped basins defined and often bisected by oblique slip faults connecting the discontinuous ends of the strike slip faults 3 increased strike slip offset produces basin shapes which we colloquially call lazy s shape for basins between sinistral faults and lazy z shape for basins between dextral faults 4

permanent scatterers for landslide investigations outcomes from the esa slam project within the slam project service for landslide monitoring launched in 2003 by the european space agency esa the permanent scatterers ps technique a multi image interferometric approach coupled with the interpretation of aerial photos and optical satellite images was carried out for landslide investigations the ps analysis was applied at a regional scale as support for landslide inventory mapping and at local scale for the monitoring of single well known slope movements for the integration of the ps measurements within a landslide inventory the arno river basin italy was chosen as test site for the presence of a high number of mass movements to date about 300 areas at high landslide risk and more than 27 000 individual landslides mapped by the institutional authorities about 350 sar images have been interferometrically processed by means of the ps technique with the detection of about 600 000 ps the use of optical images contributed spatial meaning to the point wise information provided by the ps making it easier to identify terrain features related to slope instability and the landslide boundaries here we describe the employed methodology and its impact in the updating of a preexisting landslide inventory 6 8 of the total number of landslides were characterized by ground displacement measurements from the ps 6 1 of already mapped landslides and 0 8 of new unstable areas detected through the ps analysis moreover most of the ps are located in urban areas showing that the proposed methodology is suitable for landslide mapping in areas with a quite high density of urbanization but that over vegetated areas it still suffers from the limitations induced by the current space borne sar missions e g temporal de correlation on the other hand the use of insar for the monitoring of single slow landslides threatening built up areas has provided satisfactory results allowing the measurement of superficial deformations with high accuracy on the landslide sectors characterized by a good radar reflectivity and coherence

source parameters and triggering links of the earthquake sequence in central italy from 2009 to 2016 analyzed with gps and insar data abstract from 2009 to 2016 four earthquakes mw 6 occurred in central italy which are the apr 6th 2009 earthquake aug 24th 2016 earthquake oct 26th 2016 earthquake and oct 30th 2016 earthquake to investigate their seismic mechanism triggering relationships and impacts on the surrounding areas we obtained their coseismic deformation fields using the data of interferometric synthetic aperture radar insar and global positioning system gps we constructed three variable strike fault models for the four events which can be more consistent with the actual fault and improve the overall fitting precision on this basis we calculated the coseismic slips of the first two earthquakes respectively and obtained that of the last two earthquakes by a joint inversion method then the coulomb stress changes of those four earthquakes were calculated the results show that these earthquakes are mainly caused by normal faults that strike approximately nw se or nnw sse and dips to sw or wsw with angles between 33 and 47 all these events are shallow earthquakes and the main fault slips are located in the area with depth of 0 10 km accompanied by some surface ruptures the maximal slip with a value of 3 44 m at 4 km depth was caused by the oct 30th 2016 earthquake the inverted magnitudes of the four earthquakes are mw 6 26 mw 6 20 mw 6 19 and mw 6 60 the stress changes indicate that the former earthquake accelerated the latter one successively moreover there is a seismic gap between the regions of the apr 6th 2009 and aug 24th 2016 earthquakes and a high stress accumulating area in the south of the apr 6th 2009 earthquake region so the montereale fault in the gap and the barisciano fault located on the southeast of the paganica fault might have great earthquake risks due to the massive accumulated stress

tectonic contraction across los angeles after removal of groundwater pumping effects after the 1987 whittier narrows and 1994 northridge earthquakes revealed that blind thrust faults represent a significant threat to metropolitan los angeles a network of 250 continuously recording global positioning system gps stations was deployed to monitor displacements associated with deep slip on both blind and surface faults here we augment this gps data with interferometric synthetic aperture radar imagery to take into account the deformation associated with groundwater pumping and strike slip faulting after removing these non tectonic signals we are left with 4 4 mm yr 1 of uniaxial contraction across the los angeles basin oriented n 36 degrees e perpendicular to the major strike slip faults in the area this indicates that the contraction is primarily accommodated on thrust faults rather than on the northeast trending strike slip faults we have found that widespread groundwater and oil pumping obscures and in some cases mimics the tectonic signals expected from the blind thrust faults in the 40 km long santa ana basin groundwater withdrawal and re injection produces 12 mm yr 1 of long term subsidence accompanied by an unprecedented seasonal oscillation of 55 mm in the vertical direction and 7 mm horizontally

transpressional rupture cascade of the 2016 mw 7 8 kaikoura earthquake new zealand large earthquakes often do not occur on a simple planar fault but involve rupture of multiple geometrically complex faults the 2016 m w 7 8 kaikoura earthquake new zealand involved the rupture of at least 21 faults propagating from southwest to northeast for about 180 km here we combine space geodesy and seismology techniques to study subsurface fault geometry slip distribution and the kinematics of the rupture our finite fault slip model indicates that the fault motion changes from predominantly right lateral slip near the epicenter to transpressional slip in the northeast with a maximum coseismic surface displacement of about 10 m near the intersection between the kekerengu and papatea faults teleseismic back projection imaging shows that rupture speed was overall slow 1 4 km s but faster on individual fault segments approximately 2 km s and that the conjugate oblique reverse north striking faults released the largest high frequency energy we show that the linking conway charwell faults aided in propagation of rupture across the step over from the humps fault zone to the hope fault fault slip cascaded along the jordan thrust kekerengu and needles faults causing stress perturbations that activated two major conjugate faults the hundalee and papatea faults our results shed important light on the study of earthquakes and seismic hazard evaluation in geometrically complex fault systems

migration of seismicity and earthquake interactions monitored by gps in se asia triple junction sulawesi indonesia 1 global positioning system gps measurements made in sulawesi indonesia from 1992 to 1999 detected coseismic and transient postseismic deformation related to the 1 january 1996 mw 7 9 earthquake on the north sulawesi minahassa trench these motions are superimposed on the long term secular motion 40 mm yr of the left lateral palu fault in central sulawesi and continued for about 1 5 2 years following the earthquake a string of earthquakes of magnitude 6 migrated along the minahassa trench from west to east subsequently two earthquakes of magnitude 6 occurred on or near the palu fault migrating toward the south modeling the increase in coulomb stress generated by the successive earthquakes agrees with the hypothesis of interacting events an unclamping effect possibly due to fluid migration in the palu area is also suggested by the stress computations and the detected gps displacements

an examination of seasonal deformation at the portuguese bend landslide southern california using radar interferometry 1 the portuguese bend landslide located on the palos verdes peninsula in southern california is a slow moving landslide whose activity is closely tied to infiltration from rainfall we use radar interferometry to constrain the seasonal kinematics of the landslide from 1995 to 2000 traditional interferometric synthetic aperture radar methods estimate an average downslope displacement rate of 1 00 m yr with an uncertainty range of 0 39 2 57 m yr during the summer months interferograms show a consistent loss in phase coherence over the landslide for epochs greater than 6 months especially in the winter interferograms become incoherent as a result of large displacement and decorrelation is used to map the spatial extent of slide movement through time the displacement rate increases sharply several weeks after the beginning of the rainy season as rainwater percolating into the slide elevates pore pressures phase coherence is lost when the slide velocity surpasses 2 6 m yr for interferograms with durations of a few months a physically based model based on rainfall driven landslide movement incorporates these observations to constrain hydraulic diffusivity to between 0 9 and 3 5 10 6 m2 yr

collision rotation and the initiation of subduction in the evolution of sulawesi indonesia the island of sulawesi indonesia has been shaped and deformed as a result of collision with the sula platform a sliver of continental material from the northern margin of australia new guinea the collision has resulted in rotation of the north volcanic arm of sulawesi and the development of the accretionary wedge of the north sulawesi trench the north sulawesi trench changes laterally from a zone of no active deformation in the eastern part to a wide accretionary wedge in the west early stages of thrusting produce a steep frontal slope 8 16 indicative of relatively high basal shear stress whereas the more advanced western zone of thrusting produces a gentle 2 slope consistent with low basal shear stress reported paleomagnetic data suggest post late eocene counter clockwise rotation of the north arm and the offshore geophysics are explained by a pivot of the north arm with respect to the celebes basin about the eastern end of the arc convergence between the north banda basin and southeast sulawesi is documented by the presence of the tolo thrust its outcrop is strongly arcuate and its accretionary wedge varies in width from a minimum of a few kilometers at each end to a maximum of 30 40 km in the central part the northern end transforms to the leftlateral matano fault with a reported offset of 20 km the southern end of the thrust projects toward the deformed rocks of buton but the structural relations there are not clear the matano fault zone appears to connect westward with the palu fault which forms the western transform of the north sulawesi trench the palu matano fault system acts as a trench trench transform between the north sulawesi trench and the tolo thrust and this system is described by the same rotation pole as that for the sulawesi north arm

fault geometry of 2015 mw7 2 murghab tajikistan earthquake controls rupture propagation insights from insar and seismological data abstract combining space based geodetic and array seismology observations can provide detailed information about earthquake ruptures in remote regions here we use landsat 8 imagery and alos 2 and sentinel 1 radar interferometry data combined with data from the european seismology network to describe the source of the december 7 2015 mw7 2 murghab tajikistan earthquake the earthquake reactivated a 79 km long section of the sarez karakul fault a ne oriented sinistral trans tensional fault in northern pamir pixel offset data delineate the geometry of the surface break and line of sight ground shifts from two descending and three ascending interferograms constrain the fault dip and slip solution two right stepping ne striking segments connected by a more easterly oriented segment sub vertical or steeply dipping to the west were involved the solution shows two main patches of slip with up to 3 5 m of left lateral slip on the southern and central fault segments the northern segment has a left lateral and normal oblique slip of up to a meter back projection of high frequency seismic waves recorded by the european network processed using the multitaper music approach focuses sharply along the surface break the time progression of the high frequency radiators shows that after a 10 second initiation phase at slow speed the rupture progresses in 2 phases at super shear velocity 4 3 5 km s separated by a 3 second interval of slower propagation corresponding to the passage through the restraining bend the intensity of the high frequency radiation reaches maxima during the initial and middle phases of slow propagation and is reduced by 50 during the super shear phases of the propagation these findings are consistent with studies of other strike slip earthquakes in continental domain showing the importance of fault geometric complexities in controlling the speed of fault propagation and related spatiotemporal pattern of the high frequency radiation

superficial simplicity of the 2010 el mayor cucapah earthquake of baja california in mexico the geometry of faults is usually thought to be more complicated at the surface than at depth and to control the initiation propagation and arrest of seismic ruptures the fault system that runs from southern california into mexico is a simple strike slip boundary the west side of california and mexico moves northwards with respect to the east however the m w 7 2 2010 el mayor cucapah earthquake on this fault system produced a pattern of seismic waves that indicates a far more complex source than slip on a planar strike slip fault here we use geodetic remote sensing and seismological data to reconstruct the fault geometry and history of slip during this earthquake we find that the earthquake produced a straight 120 km long fault trace that cut through the cucapah mountain range and across the colorado river delta however at depth the fault is made up of two different segments connected by a small extensional fault both segments strike n130 e but dip in opposite directions the earthquake was initiated on the connecting extensional fault and 15 s later ruptured the two main segments with dominantly strike slip motion we show that complexities in the fault geometry at depth explain well the complex pattern of radiated seismic waves we conclude that the location and detailed characteristics of the earthquake could not have been anticipated on the basis of observations of surface geology alone

radar interferometry and its application to changes in the earth s surface geophysical applications of radar interferometry to measure changes in the earth s surface have exploded in the early 1990s this new geodetic technique calculates the interference pattern caused by the difference in phase between two images acquired by a spaceborne synthetic aperture radar at two distinct times the resulting interferogram is a contour map of the change in distance between the ground and the radar instrument these maps provide an unsurpassed spatial sampling density 100 pixels km 2 a competitive precision 1 cm and a useful observation cadence 1 pass month 1 they record movements in the crust perturbations in the atmosphere dielectric modifications in the soil and relief in the topography they are also sensitive to technical effects such as relative variations in the radar s trajectory or variations in its frequency standard we describe how all these phenomena contribute to an interferogram then a practical summary explains the techniques for calculating and manipulating interferograms from various radar instruments including the four satellites currently in orbit ers 1 ers 2 jers 1 and radarsat the next chapter suggests some guidelines for interpreting an interferogram as a geophysical measurement respecting the limits of the technique assessing its uncertainty recognizing artifacts and discriminating different types of signal we then review the geophysical applications published to date most of which study deformation related to earthquakes volcanoes and glaciers using ers 1 data we also show examples of monitoring natural hazards and environmental alterations related to landslides subsidence and agriculture in addition we consider subtler geophysical signals such as postseismic relaxation tidal loading of coastal areas and interseismic strain accumulation we conclude with our perspectives on the future of radar interferometry the objective of the review is for the reader to develop the physical understanding necessary to calculate an interferogram and the geophysical intuition necessary to interpret it

analysis of active lava flows on kilauea volcano hawaii using sir c radar correlation measurements precise eruption rates of active pahoehoe lava flows on kilauea volcano hawaii have been determined using spaceborne radar data acquired by the space shuttle imaging radar c sir c a coastal site downslope from the pu9u o9o vent was imaged once per day on each of the four days of october 7 10 1994 day to day decorrelation due to resurfacing was determined by interferometric combination of the data at 15 m resolution over a wide area on successive days new lava resurfaced 335700 m 2 368775 m 2 and 356625 m 2 assuming an average pahoehoe flow thickness of 50 cm a mean effusion rate for this period is approximately 2 m 3 s the radar observations show persistent surface activity at each site rather than downslope migration of coherent lava flows

the 2010 mw 6 8 yushu qinghai china earthquake constraints provided by insar and body wave seismology 1 by combining observations from satellite radar body wave seismology and optical imagery we have determined the fault segmentation and sequence of ruptures for the 2010 mw 6 8 yushu china earthquake we have mapped the fault trace using displacements from sar image matching interferometric phase and coherence and 2 5 m spot 5 satellite images modeling the event as an elastic dislocation with three segments fitted to the fault trace suggests that the southeast and northwest segments are near vertical with the central segment dipping 70 to the southwest slip occurs mainly in the upper 10 km with a maximum slip of 1 5 m at a depth of 4 km on the southeastern segment the maximum slip in the top 1 km i e near surface is up to 1 2 m and inferred locations of significant surface rupture are consistent with displacements from sar image matching and field observations the radar interferograms show rupture over a distance of almost 80 km much larger than initial seismological and field estimates of the length of the fault part of this difference can be attributed to slip on the northwestern segment of the fault being due to an mw 6 1 aftershock two hours after the main event the remaining difference can be explained by a non uniform slip distribution with much of the moment release occurring at depths of less than 10 km the rupture on the central and southeastern segments of the fault in the main shock propagated at a speed of 2 5 km s southeastward toward the town of yushu located at the end of this segment accounting for the considerable building damage strain accumulation since the last earthquake on the fault segment beyond yushu is equivalent to an mw 6 5 earthquake

determining the sula block kinematics in the triple junction area in indonesia by gps summary the point of convergence of the eurasian philippine and australian plates is situated adjacent to the island of sulawesi indonesia the relative plate velocities are estimated by nuvel1 to be 7 to 9 cm yr 1 the complex tectonic mechanism of the triple junction has been studied over a two year period in the course of the geodyssea southeast asian project the gps investigations concentrate on measurements of both the sulawesi eastern indonesia part of the inter regional geodyssea network and a local subnetwork on sulawesi motions derived using data from the subnetwork con rm what the results of the inter regional geodyssea network have suggested that is that current deformation is high and there are distinct deformation domains in the study area on sulawesi the tectonic mechanism of the triple junction has been analysed using a rigid microblock model the triple junction area can best be interpreted as a headland of the australian plate de ected by its collision with the philippine plate thereby identifying the driving forces of the current deformation the northern part is dominated by the sula domain which shows clockwise rotation to the south it is connected to the australian plate by an ensemble of microblocks undergoing counterclockwise rotation in addition to the above our tectonic model permits the determination of the local in uence of two large earthquakes m 7 8 1996 january 1 and m 7 0 1996 july 22 on the motion of the station tomini north sulawesi more observations and a denser gps network are planned in order to study the behaviour of the palu koro fault the main fault on the western limit of the sula block

gps compared to long term geologic motion of the north arm of sulawesi geodetic data acquired in the north arm of sulawesi are compared with geologic and palaeomagnetic data from north sulawesi and the celebes sea the objective of this study is to assess whether the long term motion deduced from palaeomagnetic and geological studies is coherent with the extrapolation of the current motions measured by gps palaeomagnetic data that have been collected in the north arm of sulawesi indicate that since 5 ma about 20 to 25o of semi rigid rotation occurred about a pole located north of manado this suggests 200 to 250 km of left lateral displacement along the palu koro fault with a displacement rate of 4 cm year a rather similar displacement on the palu fault is derived using the distribution of the asymmetric magnetic anomalies of the celebes seafloor the distribution implies that 200 to 250 km of oceanic crust was subducted at the north sulawesi trench another marker for the rotation is derived from the opening of the gulf of tomini and the nw migration of the calc alkaline subduction related volcanism the far field observation by gps of 4 cm year of left lateral strike slip motion over 17 months and the 5 year average of 3 4 0 3 cm year on a transect across the palu fault fit well with the geological observations that indicate a motion of 4 to 5 cm year of the north arm we therefore conclude that the current rates deduced from gps measurements approximate the long term rates and may hence be extrapolated over a few million years 1998 elsevier science b v all rights reserved

landslides on coastal sage scrub and grassland hillslopes in a severe el nino winter the effects of vegetation conversion on sediment delivery during the 1997 1998 el nino record rainfall triggered 150 shallow landslides within a 9 5 km2 area near santa barbara cal ifornia they were studied to analyze the sediment delivery to val ley floors from landslides in coastal sage scrub and converted grasslands the conversion of coastal sage to grasslands primarily to provide pasturage for cattle is common in the region and the landscape s response may affect water quality reservoir infilling and debris flow hazards we explore the relationship between lateral root reinforcement and landslide volume by developing a slope stability analysis that incorporates root cohesion along the sides of the failure the stability analysis correctly predicts an inverse re lationship between landslide volume and hillslope angle in the sage the volumes of failures in the grasslands do not vary systemati cally with slope and are generally smaller than those in the sage from aerial photograph analysis and field mapping we find that there are 22 9 failures per square kilometer in the grasslands com pared to 13 2 failures per square kilometer in the sage despite the lower failure density in the coastal sage greater failure volumes and longer transport distances delivered more sediment to valley floors with a specific volumetric flux of 2 8 3 10 2 m 3 m 1 for this el nino compared to 1 73 10 2 m 3 m 1 in the grasslands we con clude that the conversion from vegetation with stronger and deeper roots coastal sage to vegetation with weaker and shallower roots grass has caused a pulse of increased landsliding in the grasslands because the soils are currently too thick for the prevailing root reinforcement we suggest that over time soils in the grassland hollows will become thinner as the evacuation by landslides is re peated until the landsliding rate declines to balance the soil sup plied from local colluvium production and diffusive processes upslope

stress triggering in thrust and subduction earthquakes and stress interaction between the southern san andreas and nearby thrust and strike slip faults 1 we argue that key features of thrust earthquake triggering inhibition and clustering can be explained by coulomb stress changes which we illustrate by a suite of representative models and by detailed examples whereas slip on surface cutting thrust faults drops the stress in most of the adjacent crust slip on blind thrust faults increases the stress on some nearby zones particularly above the source fault blind thrusts can thus trigger slip on secondary faults at shallow depth and typically produce broadly distributed aftershocks short thrust ruptures are particularly efficient at triggering earthquakes of similar size on adjacent thrust faults we calculate that during a progressive thrust sequence in central california the 1983 mw 6 7 coalinga earthquake brought the subsequent 1983 mw 6 0 nunez and 1985 mw 6 0 kettleman hills ruptures 10 bars and 1 bar closer to coulomb failure the idealized stress change calculations also reconcile the distribution of seismicity accompanying large subduction events in agreement with findings of prior investigations subduction zone ruptures are calculated to promote normal faulting events in the outer rise and to promote thrust faulting events on the periphery of the seismic rupture and its downdip extension these features are evident in aftershocks of the 1957 mw 9 1 aleutian and other large subduction earthquakes we further examine stress changes on the rupture surface imparted by the 1960 mw 9 5 and 1995 mw 8 1 chile earthquakes for which detailed slip models are available calculated coulomb stress increases of 2 20 bars correspond closely to sites of aftershocks and postseismic slip whereas aftershocks are absent where the stress drops by more than 10 bars we also argue that slip on major strike slip systems modulates the stress acting on nearby thrust and strike slip faults we calculate that the 1857 mw 7 9 fort tejon earthquake on the san andreas fault and subsequent interseismic slip brought the coalinga fault 1 bar closer to failure but inhibited failure elsewhere on the coast ranges thrust faults the 1857 earthquake also promoted failure on the white wolf reverse fault by 8 bars which ruptured in the 1952 mw 7 3 kern county shock but inhibited slip on the left lateral garlock fault which has not ruptured since 1857 we thus contend that stress transfer exerts a control on the seismicity of thrust faults across a broad spectrum of spatial and temporal scales

source parameters and slip distribution of the 2018 mw 7 5 palu indonesia earthquake estimated from space based geodesy abstract the 2018 mw 7 5 palu earthquake is one of the most geometrically complex events ever recorded on central sulawesi island it caused devastating tsunamis and landslides after the mainshock resulting in great casualties and damages to the infrastructures in palu city and surrounding areas in this study we combined far field insar near field sar and optical sub pixel correlation data to determine the fault geometry source parameters and fault slip distribution of this event along the palu koro fault zone our best fitting fault model contains three fault segments with variable strike angles showing that the coseismic rupture is dominated by a left lateral strike slip motion accompanied by minor normal slip and reverse slip components on the onshore segments the maximum slip is up to 8 4 m with a left lateral strike slip component of 6 8 m at a depth of 4 km on the central segment near palu city a normal slip component of 4 3 m in the left releasing step over and a reverse slip component of 3 2 m in the offshore area near the palu bay on the offshore segment the maximum slip is up to 4 2 m with a normal slip component of 1 8 m we argue that the offshore reverse slip motion might have played a key role in the generation of the palu tsunami we also suggest that the linking normal segment contributed to the rupture propagation across the left releasing step over from the central segment to the southern segment while the linking reverse segment arrested the rupture propagation across the right restraining step over to north the coulomb stress change reveals that there is possibility of future great earthquakes occurring on several major faults in the northeast of palu city our results have great significance to qualitatively assess the risk of future seismic hazards in such a geometrically complex fault system

synthetic aperture radar interferometry to measure earth s surface topography and its deformation synthetic aperture radar interferometry insar from earth orbiting spacecraft provides a new tool to map global topography and deformation of the earth s surface radar images taken from slightly different viewing directions allow the construction of digital elevation models of meter scale accuracy these data sets aid in the analysis and interpretation of tectonic and volcanic landscapes if the earth s surface deformed between two radar image acquisitions a map of the surface dis placement with tens of meters resolution and subcentimeter accuracy can be con structed this review gives a basic overview of insar for earth scientists and presents a selection of geologic applications that demonstrate the unique capabilities of insar for mapping the topography and deformation of the earth

on the application of sar interferometry to geomorphological studies estimation of landform attributes and mass movements this paper presents two examples of application of synthetic aperture radar sar interferometry insar to typical geomorphological problems the principles of insar are introduced taking care to clarify the limits and the potential of this technique for geomorphological studies the application of insar to the quantification of landform attributes such as the slope and to the estimation of landform variations is investigated two case studies are presented a first case study focuses on the problem of measuring landform attributes by interferometric sar data the interferometric result is compared with the corresponding one obtained by a digital elevation model dem in the second case study the use of insar for the estimation of landform variations caused by a landslide is detailed

fault slip distribution of the 1999 mw 7 1 hector mine california earthquake estimated from satellite radar and gps measurements we use a combination of satellite radar and gps data to estimate the slip distribution of the 1999 m w 7 1 hector mine earthquake a right lateral strikeslip earthquake that occurred on a northwest southeast striking fault in the southern california mojave desert the data include synthetic aperture radar interferograms insar from both ascending and descending orbits radar amplitude image offset fields sario for both ascending and descending azimuth directions and campaign gps observations from 55 stations provided by agnew et al 2002 we model the fault with nine segments derived from the field mapped fault rupture the sario data and aftershock locations we first estimate the dip of each fault segment as well as a single constant strike slip component across each segment resulting in an average dip of 83 to the northeast and slip of up to 5 6 m then we fix the optimal fault segment dip discretize the fault segments into 1 5 km 1 5 km patches and solve for the variable slip distribution using a nonnegative least squares method that includes an appropriate degree of smoothing our preferred solution has both right lateral strike slip and reverse faulting the estimated geodetic moment is 5 93 10 19 n m m w 7 1 similar to seismological estimates indicating that there are insignificant interseismic and postseismic deformation signals in the data we find strike slip displacements of up to 6 0 m and reverse faulting of up to 1 6 m with the maximum slip located just northwest of the epicenter most of the slip is concentrated northwest and south of the epicenter little slip is found on the northeastern branch of the fault the sario data and our modeling indicate that the amount and extent of surface fault rupture were underestimated in the field

the dynamics of strike slip step overs with linking dip slip faults fault step overs with linking dip slip faults are common features on long strike slip fault systems worldwide it has been noted by various researchers that under some circumstances earthquakes can jump across fault step overs to cascade into large events while under other circumstances rupture is arrested at step overs there is also evidence that fault step overs may be preferential locations for earthquake nucleation the present work uses the 3d finite element method to model the dynamics of strike slip fault systems with step overs and linking dip slip faults i find that the presence of a linking normal or thrust fault greatly increases the ability of earthquake rupture to propagate across the step over leading to a larger event additionally dilational step overs with linking normal faults are more prone to through going rupture than compressional step overs with linking thrust faults this difference is due to the sign of the normal stress increment on the dip slip fault caused by slip on the strike slip segments slip on the strike slip segments causes a negative unclamping normal stress increment on the linking normal fault in a dilational step over whereas the opposite effect occurs on the linking thrust fault in a compressional step over even in cases for which both dilational and compressional step overs can experience through going rupture dilational step overs typically experience higher slip particularly on the linking normal fault in the compressional case rupture nucleation on the linking thrust fault may increase the likelihood of through going rupture compared to nucleation on one of the strike slip segments near the intersections between the fault segments the stress interaction between the fault segments also causes a significant rotation of rake away from that which would be inferred from the regional stress field the results help to emphasize the importance of two way interactions between nearby fault segments during the earthquake rupture process the results also may have implications for the probability of large earthquakes along geometrically complex strike slip fault systems and may help explain why step overs sometimes act as barriers and other times as nucleation locations for large earthquakes

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

fault geometry and slip distribution at depth of the 1997 mw 7 2 zirkuh earthquake contribution of near field displacement data in this study we reestimate the source model of the 1997 mw 7 2 zirkuh earthquake northeastern iran by jointly optimizing intermediate field interferometry synthetic aperture radar data and near field optical correlation data using a two step fault modeling procedure first we estimate the geometry of the multisegmented abiz fault using a genetic algorithm then we discretize the fault segments into subfaults and invert the data to image the slip distribution on the fault our joint data model although similar to the interferometry synthetic aperture radar based model to the first order highlights differences in the fault dip and slip distribution our preferred model is 80 west dipping in the northern part of the fault 75 east dipping in the southern part and shows three disconnected high slip zones separated by low slip zones the low slip zones are located where the abiz fault shows geometric complexities and where the aftershocks are located we interpret this rough slip distribution as three asperities separated by geometrical barriers that impede the rupture propagation finally no shallow slip deficit is found for the overall rupture except on the central segment where it could be due to off fault deformation in quaternary deposits

satellite interferometric observations of displacements associated with seasonal groundwater in the los angeles basin 1 the newport inglewood fault zone nifz displays interferometric synthetic aperture radar sar phase features along most of its length having amplitudes of up to 60 mm however interpretation in terms of right lateral shallow slip along the fault fails to match the range of geologic estimates of slip recently bawden et al 2001 proposed that these phase features as well as a broader deformation pattern in the los angeles basin are due to vertical motion related to annual variations in the elevation of the water table we confirm this hypothesis through the analysis of a longer span of data consisting of 26 sar images collected by the ers 1 and ers 2 spacecraft between june 1992 and june 2000 moreover we use continuous gps measurements from 1995 to the present to establish the amplitude and phase of the vertical deformation the los angeles basin becomes most inflated one quarter of the way through the year which is consistent with water table measurements as well as with the end of the rainy season when the aquifer should be at a maximum the spatial pattern of the amplitude of the annual signal derived from continuous gps measurements is consistent with the shape of the interferometric fringes gps sites both near the nifz and in a 20 by 40 km zone within the basin also show significant n s annual variations that may be related to the differential expansion across the fault since these horizontal signals have peak to trough amplitudes of 6 mm they mask the smaller tectonic signals and need to be taken into account when interpreting gps time series of site position moreover since the groundwater signal appears to have a long term vertical trend which varies in sign depending on location it will be difficult to distinguish interseismic tectonic slip along the nifz and within the affected areas in the basin

the portuguese bend landslide abstract the portuguese bend landslide in coastal southern california is an active slow moving mass of blocks and debris that extends from the shoreline to moderate altitudes along part of the southerly margin of the palos verdes hills these hills form a peninsula that is underlain by cenozoic sedimentary and volcanic rocks draped anticlinally over a core of mesozoic schist in the southerly parts of the peninsula inherently weak units in the altamira shale member of the miocene monterey formation dip seaward in general concordance with the ground surface ground failure has been widespread in this area it evidently began in mid to late pleistocene time and it has continued intermittently to the present the portuguese bend landslide represents a reactivation of movement of the eastern part of a complex of prehistoric landslides occupying an area of approximately two square miles this latest episode of movement began in 1956 presumably in response to placement of fill during a road construction project the active slide subsequently was enlarged by sequential failure of adjoining blocks of ground and by september 1969 about 54 500 000 metric tons of debris was slowly moving downslope in an area of approximately 104 ha movement has been continuous since recent failure began in 1956 although the velocity of the active slide decreased markedly after that year between 1962 and 1972 the velocity fluctuated only slightly about an average value of about 1 cm per day the active slide is an irregular prism roughly triangular in plan view the southern side of the triangle trends approximately 1100 m east west along a stretch of shoreline that essentially coincides with the toe of the slide the other two sides of the triangle trend northeast and northwest from the ends of the toe and meet about 1200 m north of the shoreline the thickness of the moving mass differs considerably from one place to another reflecting both topographic irregularities and major undulations in the underlying surface of movement the maximum thickness is approximately 75 m movement is occurring along a distinct basal failure surface the eastern part of the slide is underlain by bedrock and is bordered by bedrock with a general structure that limits further deep seated propagation of failure to the east and northeast in contrast the western part of the slide is underlain and bordered by extensive ancient landslide deposits that are marginally stable further encroachment of the active slide westward and northwestward into these materials was viewed as a distinct possibility at the time the dissertation was prepared and has occurred since then continued movement of the portuguese bend landslide since 1956 has been due to four main factors a rise in the water table during the period 1957 1968 has been documented in the northwestern part of the moving mass and is attributable mainly to infiltration of surface runoff entering numerous open fissures that cut the surface of the slide the toe of the active slide daylights along the shoreline and is subjected to storm wave erosion so that any natural build up of resisting forces is prevented in this area the redistribution of mass as the slide has moved along an undulatory failure surface has been responsible for local fluctuations in the driving and resisting forces finally smoothing of irregularities in the failure surface by the moving slide mass must have decreased some of the forces resisting movement

satellite radar interferometry time series analysis of surface deformation for los angeles california 1 the los angeles california metropolitan area is a tectonically active region with surface deformation that is a combination of fault related tectonics plus a variety of natural and anthropogenic signals we apply the small baseline subset sbas algorithm to produce an interferometric synthetic aperture radar insar time series analysis for the los angeles area using data acquired by the ers satellites from late 1995 into 2002 the result is a space time deformation product that can be exploited to view not only the smoothly varying long term surface motion but also its time varying patterns large seasonal oscillations of the santa ana aquifer observed in southern california integrated gps network scign data are accurately matched in the insar time series moreover correlations of the insar time series with an annual sinusoid allows us to investigate the dynamics of the hydrologic system index terms 1243 geodesy and gravity space geodetic surveys 1294 geodesy and gravity instruments and techniques 1803 hydrology anthropogenic effects citation lanari r p lundgren m manzo and f casu 2004 satellite radar interferometry time series analysis of surface deformation for los angeles california geophys res lett 31 l23613 doi 10 1029 2004gl021294

glacier motion estimation using sar offset tracking procedures two image to image patch offset techniques for estimating feature motion between satellite synthetic aperture radar sar images are discussed intensity tracking based on patch intensity cross correlation optimization and coherence tracking based on patch coherence optimization are used to estimate the movement of glacier surfaces between two sar images in both slant range and azimuth direction the accuracy and application range of the two methods are examined in the case of the surge of monacobreen in northern svalbard between 1992 and 1996 offset tracking procedures of sar images are an alternative to differential sar interferometry for the estimation of glacier motion when differential sar interferometry is limited by loss of coherence i e in the case of rapid and incoherent flow and of large acquisition time intervals between the two sar images in addition an offset tracking procedure in the azimuth direction may be combined with differential sar interferometry in the slant range direction in order to retrieve a two dimensional displacement map when sar data of only one orbit configuration are available

two examples of the use of sar interferometry on displacement fields of small spatial extent interferometric combination of pairs of sar images acquired by the european ers 1 satellite maps deformation fields associated with two phenomena both of small spatial extension and located in se france the one is rapid terrain deformation caused by a landslide near the city of saint etienne de tinee and the other is slower subsidence caused by underground coal mining near gardanne unlike interferometric measurement of wide field deformation atmospheric propagation heterogeneity is not an accuracy limiting factor although the radar data confirm prior knowledge concerning the landslide such an application of sar interferometry appears difficult under normal conditions of observation using current spaceborne radar systems the study of soil subsidence however can be generalized and improves prior knowledge of the displacement field which has here been modeled assuming elastic deformation in a half space from several sources the two examples help to understand the limits of the interferometric technique

dynamics of slow moving landslides from permanent scatterer analysis high resolution interferometric synthetic aperture radar insar permanent scatterer data allow us to resolve the rates and variations in the rates of slow moving landslides satellite to ground distances range changes on landslides increase at rates of 5 to 7 millimeters per year indicating average downslope sliding velocities from 27 to 38 millimeters per year time series analysis shows that displacement occurs mainly during the high precipitation season during the 1997 1998 el nino event rates of range change increased to as much as 11 millimeters per year the observed nonlinear relationship of creep and precipitation rates suggests that increased pore fluid pressures within the shallow subsurface may initiate and accelerate these features changes in the slope of a hill resulting from increases in the pore pressure and lithostatic stress gradients may then lead to landslides

rainfall ground water flow and seasonal movement at minor creek landslide northwestern california physical interpretation of empirical relations simple ground water flow analyses can clarify complex empirical relations between rainfall and landslide motion here we present detailed data on rainfall ground water flow and repetitive seasonal motion that occurred from 1982 to 1985 at minor creek landslide in northwestern california and we interpret these data in the context of physically based theories we find that landslide motion is closely regulated by the direction and magnitude of near surface hydraulic gradients and by waves of pore pressure caused by intermittent rainfall diffusive propagation of pore pressure waves accompanies downward ground water flow along nearly vertical hydraulic gradients that exist in most of the landslide field data combined with a pore pressure diffusion analysis show that single rainstorms typically produce short period waves that attenuate before reaching the landslide base in contrast seasonal rainfall cycles produce long period waves that modify basal pore pressures but only after time lags that range from weeks to months such tune lags can depend on antecedent moisture storage and can explain variable delays between the onset of the wet season and seasonal landslide motion limit equilibrium analysis shows that when seasonal pressure waves reach the landslide base they establish a critical distribution of effective stress that delicately triggers landslide motion the critical effective stress balance is extremely sensitive to the direction and magnitude of hydraulic gradients although pervasively downward gradients instigate seasonal motion we infer from theory and limited data that ground water also may circulate locally in near surface cells the circulation can further reduce the landslide s frictional strength particularly in areas of nearly horizontal ground water flow that occur beneath steep faces of hummocks hummocky topography that results from slope instability may therefore cause ground water flow that perpetuates instability

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

shortcomings of insar for studying megathrust earthquakes the case of the mw9 0 tohoku oki earthquake 1 interferometric synthetic aperture radar insar observations are sometimes the only geodetic data of large subduction zone earthquakes however these data usually suffer from spatially long wavelength orbital and atmospheric errors that can be difficult to distinguish from the coseismic deformation and may therefore result in biased fault slip inversions to study how well insar constrains fault slip of large subduction zone earthquakes we use data of the 11 march 2011 tohoku oki earthquake mw9 0 and test insar derived fault slip models against models constrained by gps data from the extensive nationwide network in japan the coseismic deformation field was mapped using insar data acquired from multiple ascending and descending passes of the alos and envisat satellites we then estimated several fault slip distribution models that were constrained using the insar data alone onland and seafloor gps acoustic data or combinations of the different data sets based on comparisons of the slip models we find that there is no real gain by including insar observations for determining the fault slip distribution of this earthquake that said however some of the main fault slip patterns can be retrieved using the insar data alone when estimating long wavelength orbital atmospheric ramps as a part of the modeling our final preferred fault slip solution of the tohoku oki earthquake is based only on the gps data and has maximum reverse and strike slip of 36 0 m and 6 0 m respectively located northeast of the epicenter at a depth of 6 km and has a total geodetic moment is 3 6 1022 nm mw 9 01 similar to seismological estimates

monitoring of the palu koro fault sulawesi by gps years of gps measurements across the palu koro fault sulawesi indonesia state left lateral strike slip 3 4 cm yr with a small normal component 0 4 cm yr the measurements on intermediate points of the transect show that the fault is locked at a depth estimated around 8 16 km by a very simple model the best measured baseline linking the two most separate sites watatu and toboli shows very interestingly a constant rate of 2 6 cm yr from 1992 to 1995 and an increased rate of 6 3 cm yr since then this increase is due to an earthquake on january 1 1996 in the minahasa trench presumably affecting station toboli s position by 2 cm of co seismic and 2 cm of post seismic displacement which is added to its long term velocity we interpret this phenomenon as additional stress loading on the palu fault driven by the slip during the earthquake 100 km to the north east

petrogenetic implications of neodymium isotope data from the kohistan batholith north pakistan neodymium data are presented for five granitoid trondhjemite granite and leucogranite plutonic units from the kohistan batholith aged 102 ma to 29 ma these have present day l43 nd 144 nd ratios of between 0 512980 and 0 512734 calculated initial 143 nd 144 nd ratios of between 0 512861 and 0 512705 and nd values of between 6 91 and 2 04 there is a decrease in nd with time which is inversely correlative with a similar increase in sr three plutonic units matum das gilgit and shirot formed from a source enriched in sm and depleted in rb or radiogenic sr relative to bulk earth whilst a fourth unit the indus confluence acid sheets is only slightly enriched in radiogenic sr these four units define a temporal trend from the least evolved matum das pluton to the most evolved indus confluence acid sheets this trend was produced as a result of subducting oceanic sediment or seawater altered oceanic crust which melted or dehydrated and increasingly modified the isotopic composition of an original mantle protolith situated above the subducting plate the data preclude any significant input to the magmatism from ancient crust new data presented here together with other published data indicate an immature metavolcanic crustal source for the matum das pluton and a plutonic basement crustal source for the indus confluence acid sheets these crustally derived units retain a mantle isotopic signature indicating that the geochemical signature of kohistan evolved by remobilization of recently formed arc crust in addition to new inputs of mantle derived magma a fifth plutonic unit the parri acid sheets shows a clear compositional break from the other units being significantly enriched in radiogenic sr and nd with respect to bulk earth the source to the parri acid sheets is interpreted as metasedimentary rocks with a high rb sr ratio and a crustal residence time of c 70 ma

observation and modelling of the saint etienne de tinee landslide using sar interferometry abstract six different interferograms of the la clapiere landslide were derived from ers 1 sar images during the period aug 20 sept 4 1991 the coherence of the associated images is shown to remain significant over most of the surface of the landslide during the two weeks of the survey the interferograms are remarkably similar and indicate steady state displacements over at least 12 days the displacement field derived from the interferograms is shown to be characterized by a non uniform displacement gradient from top to bottom and reveals a significantly faster motion of the western part of the landslide the amplitude of the motion deduced from interferometry is shown to be in good agreement with ground measurements finally sar interferometry is shown to be able to evidence small scale instabilities which may not be observed with discrete ground measurements

evidence of supershear during the 2018 magnitude 7 5 palu earthquake from space geodesy a magnitude 7 5 earthquake hit the city of palu in sulawesi indonesia on 28 september 2018 at 10 02 43 coordinated universal time it was followed a few minutes later by a 4 7 m high tsunami palu is situated in a narrow pull apart basin surrounded by high mountains of up to 2 000 m altitude this morphology has been created by a releasing bend in the palu koro fault a rapidly moving left lateral strike slip fault here we present observations derived from optical and radar satellite imagery that constrain the ground surface displacements associated with the earthquake in great detail mapping of the main rupture and associated secondary structures shows that the slip initiated on a structurally complex and previously unknown fault to the north extended southwards over 180 km and passed through two major releasing bends the 30 km section of the rupture south of palu city is extremely linear and slightly offset from the mapped geological fault at the surface this part of the rupture accommodates a large and smooth surface slip of 4 7 m with no shallow slip deficit almost no aftershock seismicity was recorded from this section of the fault as these characteristics are similar to those from known supershear segments we conclude that the palu earthquake probably ruptured this segment at supershear velocities the devastating 2018 magnitude 7 5 earthquake in palu indonesia ruptured at supershear speeds according to evidence from space geodesy

rapid rotations about a vertical axis in a collisional setting revealed by the palu fault sulawesi indonesia global positioning system gps measurements from 1992 to 1995 indicate that the left lateral palu fault in central sulawesi slips at a rate of 38 8 mm a with a locking depth between 2 and 8 km from the measured slip rate and the historic seismicity of the fault we estimate that the palu fault currently has stored enough strain to produce a mw 7 earthquake the palu and other nearby faults accommodate rapid clockwise rotation of nearly 4 ma of e sulawesi relative to eastern sunda the rotation of east sulawesi transfers e w shortening between the pacific and eurasian plates to n s subduction of the celebes basin beneath sulawesi

microblock rotations and fault coupling in se asia triple junction sulawesi indonesia from gps and earthquake slip vector data the island of sulawesi eastern indonesia is located within the triple junction of the australian philippine and sunda plates and accommodates the convergence of continental fragments with the sunda margin we quantify the kinematics of sulawesi by modeling gps velocities and earthquake slip vectors as a combination of rigid block rotations and elastic deformation around faults we find that the deformation can be reasonably described by a small number of rapidly rotating crustal blocks relative to the sunda plate the southwestern part of sulawesi makassar block rotates anticlockwise at 1 4 myr the northeastern part of sulawesi the bangai sula domain comprises three blocks the central north sula block moves toward the nnw and rotates clockwise at 2 5 myr the northeastern manado block rotates clockwise at 3 myr about a nearby axis and east sulawesi is pinched between the north sula and makassar blocks along the boundary between the makassar block and the sunda plate gps measurements suggest that the trench accommodates 15 mm yr of slip within the makassar strait with current elastic strain accumulation the tectonic boundary between north sula and manado blocks is the gorontalo fault moving right laterally at about 11 mm yr and accumulating elastic strain the 42 mm yr relative motion between north sula and makassar blocks is accommodated on the palu koro left lateral strike slip fault zone the data also indicate a pull apart structure in palu area where the fault shows a transtensive motion and may have a complex geometry involving several active strands sulawesi provides a primary example of how collision can be accommodated by crustal block rotation instead of mountain building