crustal deformation associated with an m8 1 earthquake in the solomon islands detected by alos palsar abstract on april 1 2007 utc a large mw 8 1 interplate earthquake struck the solomon islands subduction zone where complicated tectonics result from the subduction of four plates extensive ground movements and a large tsunami occurred in the epicentral area causing severe damage over a wide area using alos palsar data and the dinsar technique we detected crustal deformation exceeding 2 m in islands close to the epicenter a slip distribution of the inferred seismic fault was estimated using geodetic information derived from dinsar processing and field investigations the result indicates large slip areas around the hypocenter and the centroid it is possible that the largest slip area is related to subduction of the plate boundary between the woodlark and australian plates a small slip area between those large slip areas may indicate weak coupling due to thermal activity related to volcanic activity on simbo island the 2007 earthquake struck an area where large earthquake has not occurred since 1970 most of this seismic gap was filled by the 2007 events however a small seismic gap still remains in the southeastern region of the 2007 earthquake

inversion of complex body waves we have developed a method that inverts seismic body waves to determine the mechanism and rupture pattern of earthquakes the rupture pattern is represented as a sequence of subevents distributed on the fault plane this method is an extension of our earlier method in which the subevent mechanisms were fixed in the new method the subevent mechanisms are determined from the data and are allowed to vary during the sequence when subevent mechanisms are allowed to vary however the inversion often becomes unstable because of the complex trade offs between the mechanism the timing and the location of the subevents many different subevent sequences can explain the same data equally well and it is important to determine the range of allowable solutions some constraints must be imposed on the solution to stabilize the inversion we have developed a procedure to explore the range of allowable solutions and appropriate constraints in this procedure a network of grid points is constructed on the i plane where and i are respectively the onset time and the distance from the epicenter of a subevent the best fit subevent is determined at all grid points then the correlation is computed between the synthetic waveform for each subevent and the observed waveform the correlation as a function of and i and the best fit mechanisms computed at each i grid point depict the character of allowable solutions and facilitate a decision on the appropriate constraints to be imposed on the solution the method is illustrated using the data for the 1976 guatemala earthquake

plio quaternary vertical motions and the subduction of the nazca ridge central coast of peru abstract the coastal region of south central peru displays raised marine terraces indicating that unlike the central peruvian coast it underwent a strong uplift since the late pliocene these recent vertical movements which were probably the most rapid motion experienced along the pacific coast of south america are commonly considered to be closely related to the subduction of the aseismic nazca ridge however several questions regarding the geometry and the precise mechanism s responsible for this deformation have not yet been fully addressed the kinematic constraints of the andean convergence suggest that the deformation of the coastal area between pisco and lomas is characterized by a quite continuous sequence of uplift events progressing southwards in spite of some difficulties encountered in precisely dating the uplifted quaternary terraces and other remnants of pliocene marine platforms it is proposed that uplift rates during the late pleistocene reached maximum values of the order of 700 mm 10 3 y as against a recently proposed estimate of 470 mm 10 3 y the reconstructed finite deformation as recorded by the study area for the last 3 ma presents a nw se oriented asymmetric dome shaped pattern it is emphasized that the strongest uplift has been occurring immediately south of the inland projection of the nazca ridge and not along the ridge axis as envisioned by the previously constructed physical models

contribution of radar interferometry to a two step inversion of the kinematic process of the 1992 landers earthquake we study the rupture process of the 1992 landers earthquake to limit the trade off between slip amplitude and rupture time that affects solutions using only seismological data we adopt a two step approach we first constrain the slip distribution and its uncertainty by independent geodetic data to recover in the second step the temporal details of the rupture propagation the first step consists of an inversion of interferometric data and global positioning system measurements both independently and together to constrain slip distribution on a three segment fault model along both strike and dip direction we use a genetic algorithm to test the uniqueness of the solution and a least squares formulation to find the model which best fits the data we conclude from the results of these geodetic inversions that interferometric data are rich enough to access the slip distribution in the case of the landers earthquake since the surface deformations are more sensitive to shallow slip in our configuration the slip amplitude is better resolved near the surface than at depth the resulting slip distribution is in agreement with geological observations at the surface and confirms the heterogeneous nature of the landers earthquake most of the slip occurs at shallow depths on the homestead valley fault second segment with a maximum value of around 7 m another high slip zone is observed on the johnson valley fault first segment at 8 km depth in the second step we invert strong motion data with the a priori final slip amplitude and its uncertainty deduced from geodetic data to constrain the time history of the rupture process this second step emphasizes a strong variation of the temporal development of the earthquake fast rupture front velocities appear within high slip zones and the rupture slows when it encounters a resistance along the fault on average the rupture front propagates with velocities close to the s wave velocity and terminates about 20 s after initiation the large variations in both slip amplitude and rupture velocity suggest that the rupture process is better described by successively breaking asperities than by a pulse propagating with constant velocity

source characteristics of the 12 november 1996 m w 7 7 peru subduction zone earthquake the 12 november 1996 m w 7 7 peru subduction zone earthquake occurred off the coast of southern peru near the intersection of the south american trench and the highest topographical point of the subducting nazca ridge we model the broadband teleseismic p waveforms from stations in the global seismic network to constrain the source characteristics of this subduction zone earthquake we have analyzed the vertical component p waves for this earthquake to constrain the depth source complexity seismic moment and rupture characteristics the seismic moment determined from the nondiffracted p waves is 3 5 1020n m corresponding to a moment magnitude m w of 7 6 7 7 the source time function for the 1996 peru event has three pulses of seismic moment release with a total duration of approximately 45 50 seconds the largest moment release occurs at approximately 35 40 seconds and is located 90km southeast of the rupture initiation approximately 70 of the seismic moment was released in the third pulse

importance of model parameterization in finite fault inversions application to the 1974 mw 8 0 peru earthquake the spatial and temporal slip distributions for the october 3 1974 mw 8 0 peru subduction zone earthquake and its largest aftershock on november 9 ms 7 1 are calculated and analyzed in terms of the inversion parameterization and tectonic significance teleseismic long period world wide standard seismograph network p and sh waveforms are inverted to obtain the rupture histories we demonstrate that erroneous results are obtained if a parameterization is used that does not allow for a sufficiently complex source involving spatial variation in slip amplitude risetime and rupture time the inversion method utilizes a parameterization of the fault that allows for a discretized source risetime and rupture time well located aftershocks recorded on a local network have the same general pattern as teleseismically determined hypocenters and help to constrain the geometry of the subduction zone for the main shock a hinged fault is preferred having a shallow plane with a dip of 11 and a deeper landward plane with a dip of 30 the preferred nucleation depth lies between 11 and 15 km a bilateral rupture is obtained with two major concentrations of slip one 60 to 70 km to the northwest of the epicenter and a second 80 to 100 km to the south and southeast of the epicenter for these source regions risetimes vary from 6 to 18 s our estimates of risetimes are consistent with the time for the rupture to traverse the dominant local asperity the slip distribution for the november 9 aftershock falls within a conspicuous hole in the main shock rupture pattern near the hypocenter of the main shock the november 9 event has a simple risetime function with a duration of 2 s aftershocks recorded by the local network are shown to cluster near the hypocenter of the impending november 9 event and downdip from the largest main shock source region slip during the main shock is concentrated at shallow depths above 15 km and extends updip from the hypocenter to near the plate boundary at the trench axis the large amount of slip at shallow depths is attributed to the absence of any significant accretionary wedge of sediments and the relatively young age and high convergence rate of the subducted plate which results in good seismic coupling near the trench axis

quaternary uplift of the peruvian coast related to the subduction of the nazca ridge 13 5 to 15 6 degrees south latitude abstract marine terraces between 13 5 and 15 6 s latitude on the peruvian coast preserve a history of quaternary sea level fluctuations and forearc movement above the subducting nazca ridge field mapping and amino acid racemization epimerization electron spin resonance radiocarbon and uranium series disequilibrium ages from mollusk shells from terrace deposits are used to define a marine terrace chronology terraces on the peruvian coast formed during global high stands of quaternary sea level in a similar way to the marine terraces on the west coast of the united states and baja california mexico a last interglacial marine terrace 125 ka is preserved on nearly every terrace flight along the coast from northeast to southwest each terrace varies in elevation because of variations in the rate of coastal uplift variations in uplift rate from northeast to southwest in the study area are explained by a simple geometric model in which the variables are the rate of plate convergence morphology of the nazca ridge and orientation of the ridge relative to the peruvian coast the oblique northeastward orientation of the ridge relative to the east west direction of plate convergence results in a ca 70 mm yr southeastward migration of the zone of nazca ridge subduction beneath the peruvian coast the coastal area above the northern flank and crest of the nazca ridge is stable or has undergone net subsidence while the coast above the ridge crest is rising at about 0 3 m kyr above the southern flank of the nazca ridge the coast is rising at a rate of ca 0 5 m kyr the fastest rate determined from studies of marine terraces on the coasts of peru and chile south of the influence of the nazca ridge uplift rates are 0 2 m kyr the pattern of faster uplift above the southern flank and slower uplift above the northern flank of the ridge is a predictable consequence of oblique ridge subduction

deep learning of aftershock patterns following large earthquakes aftershocks are a response to changes in stress generated by large earthquakes and represent the most common observations of the triggering of earthquakes the maximum magnitude of aftershocks and their temporal decay are well described by empirical laws such as bath s law1 and omori s law2 but explaining and forecasting the spatial distribution of aftershocks is more difficult coulomb failure stress change3 is perhaps the most widely used criterion to explain the spatial distributions of aftershocks4 8 but its applicability has been disputed9 11 here we use a deep learning approach to identify a static stress based criterion that forecasts aftershock locations without prior assumptions about fault orientation we show that a neural network trained on more than 131 000 mainshock aftershock pairs can predict the locations of aftershocks in an independent test dataset of more than 30 000 mainshock aftershock pairs more accurately area under curve of 0 849 than can classic coulomb failure stress change area under curve of 0 583 we find that the learned aftershock pattern is physically interpretable the maximum change in shear stress the von mises yield criterion a scaled version of the second invariant of the deviatoric stress change tensor and the sum of the absolute values of the independent components of the stress change tensor each explain more than 98 per cent of the variance in the neural network prediction this machine learning driven insight provides improved forecasts of aftershock locations and identifies physical quantities that may control earthquake triggering during the most active part of the seismic cycle neural networks trained on data from about 130 000 aftershocks from around 100 large earthquakes improve predictions of the spatial distribution of aftershocks and suggest physical quantities that may control earthquake triggering

coseismic slip resolution and post seismic relaxation time of the 1999 chi chi taiwan earthquake as constrained by geological observations geodetic measurements and seismicity summary we analysed the surface displacements estimated by global positioning system gps mea surements and systeme probatoire d observation de la terre spot image correlation and the seismicity change induced by the mw 7 6 1999 september 20 chi chi earthquake we first modelled the seismogenic zone for which we introduced a realistic geologically constrained ramp and flat geometry and estimated by joint inversion of the gps and spot data the co seismic slip distribution stressing the resolution of the model parameters the fair adjustment indicates that the ramp and flat geometry is consistent with the geodetic measurement the cal culated coseismic slip increases both towards the surface and northwards with maximum slip of approximately 15 m in good agreement with the observed surface rupture and previously ob tained slip models based on seismic waveforms this distribution may be represented to a good approximation by a linear increase of slip with a constant azimuth in the plate convergence direction special emphasis is given to the analysis of the model resolution which sharply decreases with depth in spite of the exceptionally well distributed and high quality inverted data this resolution decrease expected for any slip distribution based on surface observations only led us then to examine the seismicity as independent data to test our model following the static stress triggering hypothesis the model is accurately defined in terms of coulomb stress change in the central part of the rupture where the fault geometry is well constrained by seismic profile in contrast at the southern and northern ends it is less appropriate however the static stress triggering approach is not precise enough to determine whether fault geometry or slip distribution is less suitable we thus conclude that the analysis of seismicity in terms of coulomb stress change might not allow us to examine small scale features of seismogenic zones finally we discuss post seismic relaxation from the temporal variation of seismicity rate in contrast to the relaxation time of 0 23 0 90 yr inferred from post seismic permanent gps measurements we found that the decay of aftershock sequence follows omori s law with an 8 14 yr relaxation time we suggest that this discrepancy results from the coexistence of several different processes not all associated with the production of aftershocks

assessment of the size of large and great historical earthquakes in peru a critical reappraisal of great historical earthquakes in peru is made in order to obtain quantitative estimates of rupture length seismic moment tsunami magnitude mt and moment magnitude mw newly collected information concerning several historical earthquakes permits the evaluation of macroseismic zones and from the size of these zones the estimation of length of rupture seismic moment and magnitude mw it is found that local tsunami data provide good quantitative estimates of mt and therefore an independent way of verifying macroseismic estimates of rupture length and seismic moment a space time diagram of great historical earthquakes shows the existence of three zones roughly corresponding to the segmentation of the nazca plate hasegawa and sacks 1981 subducting under peru the northern zone looks aseismic the central one is very complex it breaks either completely or in smaller segments and it may go through long quiescence periods the recurrence time for the southern segment the more regular one is of the order of one century

joint inversion of broadband teleseismic and interferometric synthetic aperture radar insar data for the slip history of the mw 7 7 nazca ridge peru earthquake of 12 november 1996 1 the slip distribution of the 12 november 1996 mw 7 7 peru earthquake is determined using broadband teleseismic waveforms a differential sar interferogram interferometric synthetic aperture radar insar and a fault parametrization allowing slip and rupture velocity to vary along the rupture plane both data sets are inverted jointly to limit the trade off between the space and time aspects of the rupture the earthquake fault plane is located at the subduction interface it strikes parallel to the trench and dips 30 ne by inverting synthetic data we show how the insar and teleseismic data are complementary and how the joint inversion produces a gain in the spatial and temporal resolution of the slip model even with a sar interferogram that covers only part of the coseismic deformation the rupture of the 1996 peru event initiated on the southern flank of the subducted nazca ridge and propagated unilaterally toward the southeast along strike for more than 100 km at a depth between 20 and 40 km the area of maximum slip 6 7 m is located 50 km southeast of the hypocenter the total seismic moment is 4 4 1020 n m our joint inversion the source time function is approximately 60 s long and presents three major pulses of moment release the dominant one which occurred between 30 and 45 s does not correspond to the area of largest slip but to the rupture of a wide zone located about 100 km away from the hypocenter where slip reaches only 2 3 m computed coseismic coastal uplift correlates well with the location of raised marine terraces and with the topography of the coastal cordillera suggesting that these features may be related to the repetition of 1996 type events at the interface between the nazca ridge and the south american plate

seismic subduction of the nazca ridge as shown by the 1996 97 peru earthquakes by rupturing more than half of the shallow subduction interface of the nazca ridge the great november 12 1996 peruvian earthquake contradicts the hypothesis that oceanic ridges subduct aseismically the mainshock s rupture has a length of about 200 km and has an average slip of about 1 4 m its moment is 1 5 1028 dyne cm and the corresponding m w is 8 0 the mainshock registered three major episodes of moment release as shown by a finite fault inversion of teleseismically recorded broadband body waves about 55 of the mainshock s total moment release occurred south of the nazca ridge and the remaining moment release occurred at the southern half of the subduction interface of the nazca ridge the rupture south of the nazca ridge was elongated parallel to the ridge axis and extended from a shallow depth to about 65 km depth because the axis of the nazca ridge is at a high angle to the plate convergence direction the subducting nazca ridge has a large southwards component of motion 5 cm yr parallel to the coast the 900 1200 m relief of the southwards sweeping nazca ridge is interpreted to act as a rigid indenter causing the greatest coupling south of the ridge s leading edge and leading to the large observed slip the mainshock and aftershock hypocenters were relocated using a new procedure that simultaneously inverts local and teleseismic data most aftershocks were within the outline of the nazca ridge a three month delayed aftershock cluster occurred at the northern part of the subducting nazca ridge aftershocks were notably lacking at the zone of greatest moment release to the south of the nazca ridge however a lone foreshock at the southern end of this zone some 140 km downstrike of the mainshock s epicenter implies that conditions existed for rupture into that zone the 1996 earthquake ruptured much of the inferred source zone of the m w 7 9 8 2 earthquake of 1942 although the latter was a slightly larger earthquake the rupture zone of the 1996 earthquake is immediately north of the seismic gap left by the great earthquakes m w 8 8 9 1 of 1868 and 1877 the m w 8 0 antofagasta earthquake of 1995 occurred at the southern end of this great seismic gap the m w 8 2 deep focus bolivian earthquake of 1994 occurred directly downdip of the 1868 portion of that gap the recent occurrence of three significant earthquakes on the periphery of the great seismic gap of the 1868 and 1877 events among other factors may signal an increased seismic potential for that zone

iterative deconvolution of complex body waves from great earthquakes the tokachi oki earthquake of 1968 abstract a method of body wave inversion is developed in an attempt to extract the information about asperities or barriers in a fault zone a sequence of point sources each being characterized with the seismic moment the onset time and the location are iteratively derived from observed records at multi stations where the two dimensional extent of the source location is taken into account a modification is made of the iterative method of kikuchi and kanamori on the formulation of inversion procedure to facilitate the computation using this method we analyse long period p waves of the tokachi oki earthquake of 1968 mw 8 2 and obtain several significant subevents with time durations of 10 s their spatio temporal distribution shows that the rupture process consists of three characteristic stages a a stage of introductory rupture b a stage of main rupture and c a stage of aftershocks the main rupture takes place in the form of clustering around a few sites of the fault plane the largest subevent occurs in the northwestern corner the stress drop associated with this event is estimated to be 200 bars one order of magnitude higher than the stress drop averaged over the entire fault plane the sum of the seismic moments of the individual subevents amounts to 2 3 1028 dyn cm which approximately coincides with the one estimated from the analysis of long period surface waves this implies that the source of the tokachi oki earthquake consists of several major subevents with time durations of 10 s in addition to other minor subevents

joint inversion of insar gps teleseismic and strong motion data for the spatial and temporal distribution of earthquake slip application to the 1999 izmit mainshock the space time distribution of slip of the 17 august 1999 izmit earthquake is investigated by inverting synthetic aperture radar sar interferometry and global positioning system gps data together with teleseismic broadband and near field strong motion records surface offsets are used as an added constraint special emphasis is given to analysis of the resolution of the different data sets we use a four segment finite fault model and a nonlinear inversion scheme allowing slip to vary in amplitude direction and duration as well as variable rupture velocity from the inversion of synthetic data we find that the best spatial resolution can be expected in the upper half of the fault model above 12 km where coverage of the interferometric sar data is good western half of the rupture and near the gps and strong motion stations teleseismic data are found to have a lower resolution that is more evenly distributed over the fault model the joint inversion of all the data sets has an increased resolving power compared with the separate inversions and gives a more robust description of the space and time distribution of slip our study shows the importance of resolution tests in evaluating the reliability of earthquake kinematic models and it confirms that an excellent fit of a single kind of data does not necessarily imply a good retrieval of the kinematic properties of an earthquake the izmit rupture which is almost pure right lateral strike slip faulting is dominated by the bilateral breaking of a central asperity located between 29 7 e about 10 km west of the city of golcuk and 30 4 e eastern margin of sapanka lake with slip reaching 6 8 m in the depth range 6 12 km the western termination of the rupture is found near the city of yalova but large slip ends around 29 7 e about 10 km east of hersek delta a second area of large slip is required by all the data sets further east toward the city of duzce between 30 7 e and 31 1 e karadere and duzce faults this eastern slip zone which is separated from the main central asperity by an area of greatly reduced slip is less well constrained by the data however a strong motion station near the city of duzce helps to locate a high slip patch near 31 1 e in the depth range 6 12 km the total seismic moment resulting from the joint inversion is 2 4 1027 dyne cm most of the energy release occurred in a short time less than 15 sec corresponding to the bilateral breaking of the central asperity rupture propagation is relatively uniform and fast toward the west with a rupture velocity close to 3 5 km sec propagation of large slip toward the east is initially slower but it accelerates during a short time interval about 10 sec after rupture nucleation eastward progression then slows down to less than 2 km sec after 15 sec and rupture almost vanishes in amplitude ca 20 sec after initiation rupture propagation then proceeds on the easternmost karadere and duzce fault segments east of 30 7 e from 22 to ca 50 sec supershear rupture propagation is not required for modeling the waveforms considered in this study the hypocenter of the duzce earthquake which occurred 3 months later 12 november 1999 m w 7 2 is located in the immediate vicinity of the easternmost slip patch of the izmit earthquake manuscript received 28 july 2000

direct dating of weathering phenomena by 40ar39ar and k ar analysis of supergene k mn oxides abstract potassium bearing manganese oxides cryptomelane k1 2 mn3 mn4 8 o16 xh2oand hollandite k ba 1 2 mn3 mn4 8 o16 xh2o are often authigenically precipitated in weathering profiles the presence of structural potassium in manganese oxides makes these minerals datable by the k ar and 40 ar 39 ar methods dating of these phases allows us to time the progression of oxidation fronts during weathering and pedogenic processes detailed age resolution of the weathering history allows us to use deep weathering profiles as land based stratigraphic records of past climatic and geomorphic events complementing evidence from the marine sedimentary and paleontological record potential problems in manganese oxide dating such as ar and or k losses excess argon 39ar loss by recoil during neutron irradiation contamination by primary minerals resistant to weathering the presence of multiple generations of manganese oxides and proportionately low radiogenic ar yield due to adsorbed atmospheric gases are addressed the k ar and 40 ar 39 ar analytical results indicate that ar and or k losses excess 40ar and 39ar recoil seem not to pose problems in manganese oxide dating this investigation suggests that fine scale laser probe 40 ar 39 ar technique is most appropriate for dating of weathering phenomena because this technique permits us to identify contaminating phases and the presence of multiple generations of weathering minerals in the inherently complex mineral assemblage characteristic of weathering profiles k ar and 40 ar 39 ar dating of supergene k bearing manganese oxides formed during lateritization of archean and proterozoic bedrocks in the caraj s region amazonia brazil indicates that weathering started before 72 6 ma petrographic electron microscope and electron microprobe investigation reveal multiple generations of manganese oxide precipitation k ar and 40 ar 39 ar laser probe step heating results independently confirm the presence of these various generations of manganese oxides age clusters at 65 69 51 56 40 43 33 35 20 24 12 17 ma and zero age 0 2 0 2 ma suggest episodic precipitation of k mn oxides resulting from changing weathering conditions in the amazon throughout the cenozoic k ar and 40 ar 39 ar dating of supergene cryptomelane from weathering profiles in eastern minas gerais southeastern brazil suggests continuous weathering from 10 to 5 6 ma ago possibly reflecting local climatic conditions due to the proximity with the atlantic ocean

spatial and temporal distribution of slip for the 1992 landers california earthquake we have determined a source rupture model for the 1992 landers earthquake m w 7 2 compatible with multiple data sets spanning a frequency range from zero to 0 5 hz geodetic survey displacements near field and regional strong motions broadband teleseismic waveforms and surface offset measurements have been used explicitly to constrain both the spatial and temporal slip variations along the model fault surface our fault parameterization involves a variable slip multiple segment finite fault model which treats the diverse data sets in a self consistent manner allowing them to be inverted both independently and in unison the high quality data available for the landers earthquake provide an unprecedented opportunity for direct comparison of rupture models determined from independent data sets that sample both a wide frequency range and a diverse spatial station orientation with respect to the earthquake slip and radiation pattern in all models consistent features include the following 1 similar overall dislocation patterns and amplitudes with seismic moments of 7 to 8 10 26 dyne cm seismic potency of 2 3 to 2 7 km 3 2 very heterogeneous unilateral strike slip distributed over a fault length of 65 km and over a width of at least 15 km though slip is limited to shallower regions in some areas 3 a total rupture duration of 24 sec and an average rupture velocity of 2 7 km sec and 4 substantial variations of slip with depth relative to measured surface offsets the extended rupture length and duration of the landers earthquake also allowed imaging of the propagating rupture front with better resolution than for those of prior shorter duration strike slip events our imaging allows visualization of the rupture evolution including local differences in slip durations and variations in rupture velocity rupture velocity decreases markedly at shallow depths as well as near regions of slip transfer from one fault segment to the next as rupture propagates northwestward along the multiply segmented fault length the rupture front slows as it reaches the northern limit of the johnson valley landers faults where slip is transferred to the southern homestead valley fault an abrupt acceleration is apparent following the transfer this process is repeated and is more pronounced as slip is again passed from the northern homestead valley fault to the emerson fault although the largest surface offsets were observed at the northern end of the rupture our modeling indicates that substantial rupture was also relatively shallow less than 10 km in this region

joint inversion of insar and teleseismic data for the slip history of the 1999 izmit turkey earthquake the slip history of the izmit earthquake is investigated by jointly inverting sar and teleseismic data with a multi segment variable slip finite fault model surface offsets are used as an added constraint the highest slip values 5 to 7 m of right lateral displacement are associated with a strong central asperity surrounding the hypocenter the bilateral breaking of this main asperity which lasted about 10 sec dominates the source time function from the golcuk izmit area to lake sapanca a relatively good correspondence is observed between slip at depth and at the surface but farther to the west and to the east slip tends to be confined to the near surface slip in the easternmost part of the rupture duzce segment is not well resolved our analysis finds the insar and teleseismic data to be compatible and complementary this study shows the potential of the joint inversion of both data sets for a rapid determination of the spatio temporal history of large earthquakes

source parameters of the 1 october 1995 dinar turkey earthquake from sar interferometry and seismic bodywave modelling abstract the 1 october 1995 m s 6 1 dinar earthquake ruptured a 10 km section of the nw se dinar civril fault there are discrepancies between the published source parameters from seismic data with seismic moments in disagreement by over a factor of two we use both sar interferometry and seismic bodywave modelling to determine earthquake source parameters an interferogram generated from ers 1 2 sar imagery spanning the event and separated by 5 months is used to derive source parameters by a downhill simplex inversion with multiple monte carlo restarts we model the displacements in the satellite line of sight initially using uniform slip on a rectangular dislocation in an elastic half space the resultant model fault plane agrees in strike and location with the observed surface break but systematic residuals exist in the line of sight deformation field resulting in a r m s residual of 20 mm in the interferogram the residuals are reduced if the depth distribution of slip is allowed to vary spatially in four segments along a continuous fault plane our best fitting solution with a r m s misfit of 8 mm reveals two distinct areas of slip on the fault plane strike 145 dip 49 rake 270 a main rupture slipping by 1 44 m between depths of 1 and 8 km becoming deeper to the se and matching the observed surface rupture and an along strike continuation to the nw of the same fault plane but between depths of 8 and 13 km and not associated with a surface break the total geodetic moment 4 5 0 1 10 18 nm is more than twice as large as published seismic moments based on the inversion of p waveforms alone but close to the harvard cmt moment 4 7 10 18 nm we use sh waveforms in addition to the p waves used previously to determine an alternative seismic source mechanism sh waves constrain the depth to be shallower than solutions based on p waves alone agreeing with the depths from the interferometric inversion and resulting in a larger moment 3 1 0 4 10 18 nm than the previous bodywave estimates 2 2 1 10 18 nm the cmt moment reduces in magnitude to a similar size 3 3 10 18 nm if the centroid depth and fault dip are constrained to the values determined from bodywave modelling and interferometry thus the geodetic moment is 40 bigger than the moment determined from seismology

the 2009 l aquila mw 6 3 earthquake a new technique to locate the hypocentre in the joint inversion of earthquake rupture process summary a new technique is presented to jointly invert the teleseismic and interferometric synthetic aperture radar insar data by simultaneously searching for the hypocentre and the relative weight of insar data in this technique the parameters of causative fault is determined by using insar data first and then the hypocentre is searched for by jointly inverting teleseismic and insar data with the assumption that each subfault on the fault is a potential hypocentre with this technique we investigated the source rupture process of the 2009 april 6 l aquila mw 6 3 earthquake without the use of the existing hypocentre locations our estimated hypocentre is 42 366 n 13 385 e depth 6 9 km with an uncertainty of 1 2 km similar to the hypocentre 42 348 n 13 380 e depth 9 5 km determined by national institute of geophysics and volcanology ingv using arrival time data within the epicentral distance of 50 km our joint inversion suggests a scalar moment of 3 5 1018 nm equivalent to a moment magnitude of mw 6 3 the source process consists of two subevents with a total duration of 7 7 s the first event 0 3 s corresponds to the slip patch near the hypocentre and the second in the next 4 7 s ruptured the other slip patch at 4 16 km along the strike direction these unilateral rupture characteristics of the l aquila earthquake are confirmed by the apparent source time functions astfs analysis in addition two resolution tests are performed to check the reliability of this work clarifying the differences between the inversion results with teleseismic data only insar data only and joint inversion indicating that a higher resolution can be achieved through the joint inversion

inversion of strong ground motion and teleseismic waveform data for the fault rupture history of the 1979 imperial valley california earthquake a least squares point by point inversion of strong ground motion and teleseismic body waves is used to infer the fault rupture history of the 1979 imperial valley california earthquake the imperial fault is represented by a plane embedded in a half space where the elastic properties vary with depth the inversion yields both the spatial and temporal variations in dislocation on the fault plane for both right lateral strike slip and normal dip slip components of motion inversions are run for different fault dips and for both constant and variable rupture velocity models effects of different data sets are also investigated inversions are compared which use the strong ground motions alone the teleseismic body waves alone and simultaneously the strong ground motion and teleseismic records the inversions are stabilized by adding both smoothing and positivity constraints the moment is estimated to be 5 0 10 25 dyne cm and the fault dip 90 5 dislocation in the hypocentral region south of the united states mexican border is relatively small and almost dies out near the border dislocation then increases sharply north of the border to a maximum of about 2 m under interstate 8 dipslip motion is minor compared to strike slip motion and is concentrated in the sediments the best fitting constant rupture velocity is 80 per cent of the local shear wave velocity however there is a suggestion that the rupture front accelerated from the hypocenter northward the 1979 imperial valley earthquake can be characterized as a magnitude 5 earthquake at the hypocenter which then grew into or triggered a magnitude 6 earthquake north of the border

quaternary uplift and seismic cycle deformation peninsula de nicoya costa rica differing rates and styles of quaternary deformation along the costa rican fore arc reflect segmentation of the trench corresponding with three contrasting domains of subducting sea floor offshore rapid upward flexure of the southern fore arc segment results from the subduction of the buoyant cocos ridge whereas moderate deformation along the central fore arc segment reflects the subduction of buoyant seamounts in contrast the northern costa rican fore arc deforms in response to the subduction of relatively dense sea floor devoid of major bathymetric anomalies quaternary geomorphic evidence and earthquake oral histories from the peninsula de nicoya within the northern costa rican fore arc demonstrate arcward tilting of the fore arc crust with discrete uplift events occurring during large subduction earthquakes uplift rates calculated from the late holocene cabuya terrace along the peninsula s trench perpendicular southeastern coast decrease systematically toward the arc from 4 5 m k y at cabuya to 1 7 m k y at montezuma 8 km to the northeast an uplifted carbonate beachrock horizon radiocarbon age 4500 5200 yr b p correlated between cabuya and montezuma is tilted 0 1 downward toward the arc although quaternary uplift is evident as far arcward as tambor 10 km northeast of montezuma uplifted terraces are absent between tambor and the golfo de nicoya a submerged archaeological site radiocarbon age 2500 yr b p located along the golfo de nicoya coast 30 km northeast of montezuma demonstrates late holocene subsidence of 0 5 m k y these data indicate net late holocene arcward tilting of the peninsula at an angular rotation rate of between 0 01 and 0 02 k y oral histories describing the m 7 7 nicoya subduction earthquake of 5 october 1950 provide evidence of seismic cycle deformation along the peninsula s southwestern coast between puerto carrillo and nosara interviews with 48 residents show that coseismic uplift of at least 1 m affected this coastline and that a significant fraction of this uplift has subsequently been reversed during four decades of gradual subsidence the coseismic deformation pattern estimated from a uniform slip dislocation model for the 1950 earthquake is consistent with both geomorphic and oral history evidence these observations suggest that seismic cycle deformation functions as an important mechanism of vertical tectonism within the costa rican fore arc arcward rotation and doming of the peninsula de nicoya during the quaternary may reflect repeated cycles of sudden coseismic deformation followed by gradual postseismic and or interseismic crustal movement

fracture network characterization using stress based tomography information on structural features of a fracture network at early stages of enhanced geothermal system egs development is mostly restricted to borehole images and if available outcrop data however using this information to image discontinuities in deep reservoirs is difficult wellbore failure data provides only some information on components of the in situ stress state and its heterogeneity our working hypothesis is that slip on natural fractures primarily controls these stress heterogeneities based on this we introduce stress based tomography in a bayesian framework to characterize the fracture network and its heterogeneity in potential egs reservoirs in this procedure first a random initial discrete fracture network dfn realization is generated based on prior information about the network the observations needed to calibrate the dfn are based on local variations of the orientation and magnitude of at least one principal stress component along boreholes a markov chain monte carlo mcmc sequence is employed to update the dfn iteratively by a fracture translation within the domain the markov sequence compares the simulated stress profile with the observed stress profiles in the borehole evaluates each iteration with metropolis hastings acceptance criteria and stores acceptable dfn realizations in an ensemble finally this obtained ensemble is used to visualize the potential occurrence of fractures in a probability map indicating possible fracture locations and lengths we test this methodology to reconstruct simple synthetic and more complex outcrop based fracture networks and successfully image the significant fractures in the domain

rupture history of the 1984 morgan hill california earthquake from the inversion of strong motion records near source strong motion velocity records and teleseismic short period p waveforms are modeled to obtain the spatial and temporal distribution of slip for the 1984 morgan hill earthquake both forward modeling and constrained least squares inversion techniques are used to interpret the strong motion velocity waveforms in the frequency range of approximately 0 2 to 2 0 hz these data support a nearly unilateral rupture to the southeast with a rupture propagation velocity of nine tenths of the local s wave velocity the majority of the slip occurs over a fault length of 25 km and to a first approximation can be interpreted as two main source regions each with an extent of about 5 km with their centers separated by about 12 km however each of the sources has detailed structure of its own and a simple two point source model is not an accurate representation of the morgan hill earthquake the second source occurs about 4 5 sec after the first and is approximately 3 times larger the maximum dislocation on the fault plane is about 1 m the total moment of the earthquake is estimated to be 2 1 10 25 dyne cm the morgan hill earthquake offers convincing evidence for very inhomogeneous slip and stress distributions on shallow strike slip faults