offshore killer whale tracking using multiple hydrophone arrays to study delphinid near surface movements and behavior two l shaped hydrophone arrays and one vertical hydrophone line array were deployed at shallow depths 125 m from the floating instrument platform r p flip moored northwest of san clemente island in the southern california bight a three dimensional propagation model based passive acoustic tracking method was developed and used to track a group of five offshore killer whales orcinus orca using their emitted clicks in addition killer whale pulsed calls and high frequency modulated hfm signals were localized using other standard techniques based on these tracks sound source levels for the killer whales were estimated the peak to peak source levels for echolocation clicks vary between 170 205 db re 1 pa 1 m for hfm calls between 185 193 db re 1 pa 1 m and for pulsed calls between 146 158 db re 1 pa 1 m

depth dependent acoustic features of diving sperm whales physeter macrocephalus in the gulf of mexico three dimensional dive trajectories of three sperm whales in the gulf of mexico have been obtained by measuring the relative arrival times and bearings of the animals acoustic multipath reflections using two elements of a towed hydrophone array deployed at an unknown depth and orientation within the first 6 12 min of the start of a dive the intervals between successive clicks of all three whales corresponded closely with the two way travel time of an acoustic pulse traveling vertically between the animals position and the ocean bottom the click spectra contained multiple peaks including a faint band of energy originally centered near 10 khz as the animals descended over 500 m in depth the center frequency of this band shifted to nearly 15 khz but subsequently remained near this value during the rest of the dive this frequency shift is consistent with that expected from energy scattering from an ensemble of incompressible small scale air filled resonators with diameters on the order of 4 mm one possible candidate for such an ensemble is proposed to reside in the collapsed frontal sac of the animal a comparison of the received levels for the bottom and direct multipath arrivals indicates that the whales acoustic directivity must range between 10 30 db in the 5 20 khz region

kalman filter based approach for multisensor multitrack and multitemporal insar a kalman filter based approach is presented for resolving 3 d surface displacements using multisensor multitrack and multitemporal interferometric synthetic aperture radar sar measurements measurements from each interferogram are projected into the three reference directions and combined in the kalman filter model with displacements determined from previous interferograms to produce updated displacement measurements both simulated and real data sets are used to test the proposed approach it is found that the method works well when the measurement noise is low the displacements in the north direction however are much lower in accuracy than those in the other two directions and even become unstable when the measurement noise is high due to the polar orbiting imaging geometries of the current satellite sar sensors

a microseismicity survey of axial seamount juan de fuca ridge an array of ocean bottom seismometers and hydrophones were deployed within the caldera of axial seamount located at the intersection of the cobb eickelberg seamount chain and the juan de fuca ridge recent manned submersible dives have discovered the presence of two distinct hydrothermal vent fields the objective of the microseismicity survey was to determine baseline information necessary for designing an optimal experiment to monitor seismicity associated with submarine volcanic and hydrothermal systems with an instrument deployment period of eight days over 1500 events were recorded and examined most events occurred within three periods of swarm activity the location of the swarm events is believed to be within the low temperature vent field in the northwest portion of axial s caldera these impulsive high frequency events are interpreted to be tectonic in origin no harmonic tremor like events were observed on any of the instruments indicating a lack of magmatic movement only nine local events were recorded on more than one instrument and none of these could be located unambiguously monochromatic 20 hz signals were also recorded and are interpreted to originate from whales observed in the immediate vicinity

one hydrophone method of estimating distance and depth of phonating dolphins in shallow water previous attempts at localizing cetaceans have generally used multiple hydrophone arrays and multichannel recording systems in this paper a low budget localization technique using only one hydrophone is described the time delays of the signals traveling via the surface and bottom reflection paths to the hydrophone relative to the direct signal are used to calculate the distance and the depth of a phonating animal only two additional measures the depth of the bottom and hydrophone have to be taken the method requires relatively shallow waters and a flat bottom surface echolocating and burst pulsing hawaiian spinner dolphins stenella longirostris at the waianae coast of oahu hawaii were localized over different bottom substrates a tracking range of up to 100 m was achieved the accuracy of the method is estimated by the total error differential technique the relative distance estimation error is below 35 and the absolute depth error below 0 7 m so that the location method is sufficiently precise for examining source levels in our study area because of its simplicity the method ideally complements sound recordings and visual sightings of marine mammals and could lead to a better understanding of the nature and use of click trains by dolphins

liquefaction evidence for the strength of ground motions resulting from late holocene cascadia subduction earthquakes with emphasis on the event of 1700 a d during the past decade paleoseismic studies done by many researchers in the coastal regions of the pacific northwest have shown that regional downdropping and subsequent tsunami inundation occurred in response to a major earthquake along the cascadia subduction zone this earthquake occurred almost certainly in 1700 a d and is believed by many to have been of m 8 5 9 or perhaps larger in order to characterize the severity of ground motions from this earthquake we report on a field search and analysis of seismically induced liquefaction features the search was conducted chiefly along the banks of islands in the lowermost columbia river of oregon and washington and in stream banks along smaller rivers throughout southwestern washington to a lesser extent the investigation included rivers in central oregon numerous small to moderate sized liquefaction features from the earthquake of 1700 a d were found in some regions but there was a notable lack of liquefaction features in others the regional distribution of liquefaction features is evaluated as a function of geologic and geotechnical factors in different field settings near the coast our use of widely different field settings each in which we independently assess the strength of shaking and arrive at the same conclusion enhances the credibility of our interpretations our regional inventory of liquefaction features and preliminary geotechnical analysis of liquefaction potential provide substantial evidence for only moderate levels of ground shaking in coastal washington and oregon during the subduction earthquake of 1700 a d additionally it appears that a similar conclusion can be reached for an earlier subduction earthquake that occurred within the past 1100 years which also has been characterized by others as being m 8 or greater on the basis of more limited data for older events collected in our regional study it appears that seismic shaking has been no stronger throughout holocene time our interpreted levels of shaking are considerably lower than current estimates in the technical literature that use theoretical and statistical models to predict ground motions of subduction earthquakes in the cascadia region because of the influence of estimated ground motions from cascadia subduction zone earthquakes on seismic hazard evaluations more paleoliquefaction and geotechnical field studies are needed to definitively bracket the strength of shaking with further work it should be possible to extend the record of seismic shaking through much of holocene time in large portions of washington and oregon

sounds source levels and associated behavior of humpback whales southeast alaska humpback whales in southeast alaskan waters produced five categories of sounds moans grunts pulse trains blowhole associated sounds and surface impacts frequencies hz of moans and grunts were 20 1900 major energy in low frequency pulse trains was in a band of 25 80 hz with pulse duration of 300 400 ms blowhole associated sounds recorded as transiting whales encountered one another were of two types shrieks 555 2000 hz and trumpetlike horn blasts with fundamental at 414 hz median pulses and spread spectrum noise were associated with gas bubble formation and explosive bursts respectively in connection with spiral feeding maneuvers surface impacts resulted from fluke or flipper slaps in sequences of 3 21 sounds source levels ranged from 162 low frequency pulse trains to 192 db surface impacts re 1 pa 1 m songs commonly heard on winter breeding grounds were absent from our recordings feeding and perhaps certain other whale activities can be monitored based on sound production

calibration and comparison of the acoustic location methods used during the spring migration of the bowhead whale balaena mysticetus off pt barrow alaska 1984 1993 between 1984 and 1993 visual and acoustic methods were combined to census the bering chukchi beaufort bowhead whale balaena mysticetus population passive acoustic location was based on arrival time differences of transient bowhead sounds detected on sparse arrays of three to five hydrophones distributed over distances of 1 5 4 5 km along the ice edge arrival time differences were calculated from either digital cross correlation of spectrograms old method or digital cross correlation of time waveforms new method acoustic calibration was conducted in situ in 1985 at five sites with visual site position determined by triangulation using two theodolites the discrepancy between visual and acoustic locations was 1 5 of visual range and less than 0 7 of visual bearing for either method comparison of calibration results indicates that the new method yielded slightly more precise and accurate positions than the old method comparison of 217 bowhead whale call locations from both acoustic methods s

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

active tectonics in eastern lunana nw bhutan implications for the seismic and glacial hazard potential of the bhutan himalaya 1 paleoseismological investigations brittle fault analysis and paleostrain calculations combined with the interpretation of satellite imagery and flood wave modeling were used to investigate the seismic and associated glacial hazard potential in eastern lunana a remote area in nw bhutan seismically induced liquefaction features cracked pebbles and a surface rupture of about 6 8 km length constrain the occurrence of m 6 earthquakes within this high altitude periglacial environment which are the strongest earthquakes ever been reported for the kingdom of bhutan seismicity occurs along conjugate sets of faults trending ne sw to nnw sse by strike slip and normal faulting mechanism indicating e w extension and n s shortening the strain field for these conjugate sets of active faults is consistent with widespread observations of young e w expansion throughout southern tibet and the north himalaya we expect however that n s trending active strike slip faults may even reach much farther to the south at least into southern bhutan numerous glacial lakes exist in the investigation area and today more than 100 106 m3 of water are stored in moraine dammed and supraglacial lakes which are crosscut by active faults strong earthquakes may trigger glacial lake outburst floods and the impact of such flash floods may be worst 80 km downstream where the valley is broad and densely populated consequently tectonic models of active deformation have to be closely linked with glacial hazard evaluation and require rethinking and modification

acoustic detection of a seafloor spreading episode on the juan de fuca ridge using military hydrophone arrays until recently no practical method has been available to continuously monitor seismicity of seafloor spreading centers the availability of the u s navy s sound surveillance system sosus for environmental research has allowed the continuous monitoring of low level seismicity of the juan de fuca ridge in the northeast pacific on june 22 1993 noaa installed a prototype system at u s naval facility whidbey island to allow real time acoustic monitoring of the juan de fuca ridge using sosus on june 26 2145 gmt a burst of low level seismic activity with accompanying harmonic tremor was observed and subsequently located near 46 15 n 129 53 w on the spreading axis of the juan de fuca ridge over the following 2 days the activity migrated to the nne along the spreading axis with the final locus of activity near 46 31 5 n 129 35 w the nature of the seismicity was interpreted to represent a lateral dike injection with the possibility of eruption on the seafloor based on this interpretation a response effort was initiated by u s and canadian research vessels and both warm water plumes and fresh lavas were subsequently identified at the site

satellite interferometry for mapping surface deformation time series in one two and three dimensions a new method illustrated on a slow moving landslide abstract space borne differential interferometric synthetic aperture radar dinsar has been extensively used in the last two decades to measure ground surface deformation providing key information for the characterization and understanding of many natural and anthropogenic processes however conventional dinsar technique measures only one component of the surface deformation i e the satellite s line of sight los causing the interpretation of dinsar measurements to be challenging and potentially narrowing the understanding of the mechanisms and dynamics of the deformation processes at work presently available methods that estimate 3d surface deformation from dinsar generally operate on individual interferograms and therefore do not produce 3d surface deformation time series however the availability of time series is essential for studying surface deformation processes bringing information on e g temporally and spatially variable external forcing conditions and characteristics of future deformation patterns the multidimensional small baseline subset msbas method was already able to produce 2d east and vertical surface deformation time series from multi tracks and multi sensors dinsar data here we propose a novel version of the msbas msbas 3d method that can produce 3d north east and vertical surface deformation time series from ascending and descending dinsar data this new method proposes measuring the surface deformation for processes producing motion parallel to the surface such as landslides and glacier flows while conserving the dinsar accuracy the ability of msbas 3d to capture the full 3d deformation pattern of processes with a surface signature is illustrated for a large slow moving deep seated landslide for which long dinsar and dgnss time series as well as ground truth data are available surface deformation is measured over a four year period using 1d los 2d and 3d msbas methods and the advantages and limitations of each approach are described in this case the novel msbas 3d technique produces superior results that greatly simplify interpretation of the processes at work the msbas 3d software can be downloaded from http insar ca

tracking sperm whale physeter macrocephalus dive profiles using a towed passive acoustic array a passive acoustic method is presented for tracking sperm whale dive profiles using two or three hydrophones deployed as either a vertical or large aperture towed array the relative arrival times between the direct and surface reflected acoustic paths are used to obtain the ranges and depths of animals with respect to the array provided that the hydrophone depths are independently measured besides reducing the number of hydrophones required exploiting surface reflections simplifies automation of the data processing experimental results are shown from 2002 and 2003 cruises in the gulf of mexico for two different towed array deployments the 2002 deployment consisted of two short aperture towed arrays separated by 170 m while the 2003 deployment placed an autonomous acoustic recorder in tandem with a short aperture towed array and used ship noise to time align the acoustic data the resulting dive profiles were independently checked using single hydrophone localizations whenever multipath reflections from the ocean bottom could be exploited to effectively create a large aperture vertical array this technique may have applications for basic research and for real time mitigation for seismic airgun surveys

matched field processing geoacoustic inversion and source signature recovery of blue whale vocalizations matched field processing mfp and global inversion techniques have been applied to vocalizations from four whales recorded on a 48 element tilted vertical array off the channel islands in 1996 global inversions from selected whale calls using as few as eight elements extracted information about the surrounding ocean bottom composition array shape and the animal s position these inversion results were then used to conduct straightforward mfp on other calls the sediment sound speed inversion estimates are consistent with those derived from sediment samples collected in the area in general most animals swam from the east to west but one animal remained within 500 m of its original position over 45 min all whales vocalized between 10 and 40 m depth three acoustic sequences are discussed in detail the first illustrating a match between an acoustic track and visual sighting the second tracking two whales to ranges out to 8 km and the final sequence demonstrating high resolution dive profiles from

acoustic and visual studies of blue whales near the california channel islands preliminary results are presented from a combined acoustic and visual study of blue whales in the channel islands national marine sanctuary off the california coast conducted during four 3 day expeditions in july 1996 acoustic recordings were collected using gps positioned sonobouys arrays with up to five sonobuoys deployed at approximately 1 km spacing visual observations were made to estimate the number of blue whales in the vicinity of the arrays and to record whale behaviors significant numbers of blue whales 5 15 were sighted each day and as many as 100 blue whale calls per hour were recorded about one third of the time large ships transited through this area providing loud low frequency sound sources to examine blue whale sensitivity to noise low frequency blue whale calls similar to those previously designated a and b in the literature were recorded additional blue whale calls include an approximately 4 s duration frequency downswept tone between 30 and 80 hz often heard at about the same intensity as the more typical a and b calls cross correlation of signals received by sonobuoys provides information to localize calling whales the location accuracy relative to the different call types will be discussed

bowhead whale localization using time difference of arrival data from asynchronous recorders this paper estimates bowhead whale locations and uncertainties using nonlinear bayesian inversion of the time difference of arrival tdoa of low frequency whale calls recorded on onmi directional asynchronous recorders in the shallow waters of the northeastern chukchi sea alaska a y shaped cluster of seven autonomous ocean bottom hydrophones separated by 0 5 9 2 km was deployed for several months over which time their clocks drifted out of synchronization hundreds of recorded whale calls are manually associated between recorders the tdoa between hydrophone pairs are calculated from filtered waveform cross correlations and depend on the whale locations hydrophone locations relative recorder clock offsets and effective waveguide sound speed a nonlinear bayesian inversion estimates all of these parameters and their uncertainties as well as data error statistics the problem is highly nonlinear and a linearized inversion did not produce physically realistic results whale location uncertainties fro

localization of marine mammals near hawaii using an acoustic propagation model humpback whale songs were recorded on six widely spaced receivers of the pacific missile range facility pmrf hydrophone network near hawaii during march of 2001 these recordings were used to test a new approach to localizing the whales that exploits the time difference of arrival time lag of their calls as measured between receiver pairs in the pmrf network the usual technique for estimating source position uses the intersection of hyperbolic curves of constant time lag but a drawback of this approach is its assumption of a constant wave speed and straight line propagation to associate acoustic travel time with range in contrast to hyperbolic fixing the algorithm described here uses an acoustic propagation model to account for waveguide and multipath effects when estimating travel time from hypothesized source positions a comparison between predicted and measured time lags forms an ambiguity surface or visual representation of the most probable whale position in a horizontal plane around the array this is an important benefit because it allows for automated peak extraction to provide a location estimate examples of whale localizations using real and simulated data in algorithms of increasing complexity are provided

analysis of the evolution of ground movements in a low densely urban area by means of dinsar technique abstract this paper presents an application example of the use of the differential interferometry synthetic aperture radar technique dinsar for monitoring ground movements in a geologically complex area around the village of suria ebro basin catalonia ne spain associated to underground mining activities and to the presence of a salt dome the analysis has been mostly performed in a rural environment affected by ground movements with different patterns magnitudes and causes a total of fifty sar images recorded between 1995 and 2007 were processed to generate the interferograms in order to study the non linear trends or changes of the ground surface behavior the dinsar technique was applied in two sets of images the interferometric results in the form of vertical displacement rate maps were checked against conventional surveying and gps measurements the results present a significant discrepancy in some location due to the wrapping of the phase when both fast and significant deformations occur in order to avoid the latter effect and improve the accuracy of the results all sar images were reprocessed using topographic leveling and gps data of different monitored points to support the dinsar interpretation a detailed geological reconnaissance of the study area was carried out as well as an inventory of ground movement indicators four different patterns of ground movement have been identified active shifting subsidence associated to the progression of the mining exploitation fronts residual subsidence on abandoned galleries with a decreasing rate of closure uplifting due to the intrusion of the salt dome and sudden ground collapses sinkholes caused by the dissolution of soluble materials laying close to the ground surface

delphinid echolocation click detection probability on near seafloor sensors the probability of detecting echolocating delphinids on a near seafloor sensor was estimated using two monte carlo simulation methods one method estimated the probability of detecting a single click cue counting the other estimated the probability of detecting a group of delphinids group counting echolocation click beam pattern and source level assumptions strongly influenced detectability predictions by the cue counting model group detectability was also influenced by assumptions about group behaviors model results were compared to in situ recordings of encounters with risso s dolphin grampus griseus and presumed pantropical spotted dolphin stenella attenuata from a near seafloor four channel tracking sensor deployed in the gulf of mexico 25 537 n 84 632 w depth 1220 m horizontal detection range received level and estimated source level distributions from localized encounters were compared with the model predictions agreement between in situ results and model predictions suggests that

simple methods of estimating source levels and locations of marine animal sounds this paper describes three relatively simple methods of estimating source levels of marine animal sounds by estimating the source distance acoustically using one or two hydrophones the methods are logistically simpler than using arrays of hydrophones of known positions but are accurate over a smaller range of distances one method makes use of the differences in the arrival times and levels of the signals received at two hydrophones from the same sound emission no knowledge of the positions of the hydrophones is required however if these are known the position of the source can be determined with left right ambiguity the second method uses the difference in received levels only but requires the hydrophone spacing to be known adequate accuracy requires the source to be significantly closer to one hydrophone than to the other third if the direct and surface reflected arrivals can be separated the source level can be determined with a single hydrophone the methods require accurately calibrated hydrophones

analysis and localization of blue whale vocalizations in the solomon sea using waveform amplitude data during the woodlark basin seismic experiment in eastern papua new guinea 1999 2000 an ocean bottom seismic array recorded marine mammal vocalizations along with target earthquake signals the array consisted of 14 instruments 7 of which were three component seismometers with a fourth component hydrophone they were deployed at 2 0 3 2 km water depth and operated from september 1999 through february 2000 while whale vocalizations were recorded throughout the deployment this study focuses on 3 h from december 21 1999 during which the signals are particularly clear the recordings show a blue whale song composed of a three unit phrase that song does not match vocalization characteristics of other known pacific subpopulations and may represent a previously undocumented blue whale song animal tracking and source level estimates are obtained with a bayesian inversion method that generates probabilistic source locations the bayesian method is augmented to include travel time estimates from seismometers and hydrophones and acoustic signal amplitude tracking results show the whale traveled northeasterly over the course of 3 h covering approximately 27 km the path followed the edge of the woodlark basin along a shelf that separates the shallow waters of the trobriand platform from the deep waters of the basin

location of instruments on the seafloor by joint adjustment of instrument and ship positions the problem of determining accurate locations for arrays of underwater instruments is similar to the problem of locating local earthquakes by utilizing a limited number of receivers but is complicated by the fact that estimated errors in longitude and latitude of a given receiver ship position are nonzero and are typically correlated estimates of ship positions at sea are commonly determined by fixes from the navy transit navigation satellite system this system calculates position error ellipses which vary in size and orientation from fix to fix deviations in the orientations of the principal axes of the error ellipses from north south and east west result in the introduction of off diagonal elements in the ship position variance matrix tying each ship fix to a stationary array of ocean bottom seismometers obs s using acoustic ranging allows averaging of fixes thus solving simultaneously for ship and obs positions puts tight constraints on the system as a whole and especially on the relative positions of the obs s in addition to ship positions the data required to locate the instruments are two way travel times between the ship and transponders on the instruments and initial depth estimates of obs s read from the bathymetry the parameters which we solve for are the locations of the instruments including depth and of the ship at each fix the forward problem calculating acoustic travel times from distances between ship fixes and obs s is solved by a ray shooting algorithm this system of equations is linearized and transformed to diagonalize the covariances it is then solved iteratively by inverting the data jointly using singular value decomposition and step length damping the solution includes the covariances of the parameters we show calculations of positions of four obs s for deployments during three experiments including the rivera oceanic seismic experiment rose typical fix error ellipses 1 are 300 m by 200 m and resulting instrument position uncertainties are approximately 100 m relative instrument positions are accurate to about 50 m relative errors can be decreased to 10 to 20 m by using simultaneous rather than sequential ranging

accuracy of an acoustic location system for monitoring the position of duetting songbirds in tropical forest a field test was conducted on the accuracy of an eight microphone acoustic location system designed to triangulate the position of duetting rufous and white wrens thryothorus rufalbus in costa rica s humid evergreen forest eight microphones were set up in the breeding territories of 20 pairs of wrens with an average intermicrophone distance of 75 2 2 6 m the array of microphones was used to record antiphonal duets broadcast through stereo loudspeakers the positions of the loudspeakers were then estimated by evaluating the delay with which the eight microphones recorded the broadcast sounds position estimates were compared to coordinates surveyed with a global positioning system gps the acoustic location system estimated the position of loudspeakers with an error of 2 82 0 26 m and calculated the distance between the male and female loudspeakers with an error of 2 12 0 42 m given the large range of distances between duetting birds this relatively low level of error demonstrates that the acoustic location system is a useful tool for studying avian duets location error was influenced partly by the difficulties inherent in collecting high accuracy gps coordinates of microphone positions underneath a lush tropical canopy and partly by the complicating influence of irregular topography and thick vegetation on sound transmission

coseismic three dimensional displacements determined using sar data theory and an application test we present a methodology to construct three dimensional deformation maps using different parameters that can be extracted using sar data we apply the methodology using envisat sar data before and after the december 26 th 2003 mw 6 6 bam earthquake in iran to determine spatial quasi continuous three dimensional coseismic deformation maps two near vertical deformation offset components are computed using envisat asar differential interferometry dinsar while two horizontal deformation offset components are measured using sub pixel correlation techniques applied to asar amplitude images using the presented methodology we combine four unevenly precise independent projections of surface coseismic deformation to obtain the full three dimensional coseismic deformation field caused by an earthquake the full 3 d coseismic displacement vector is modeled using elastic deformation models constraining details of the fault geometry and slip distribution at depth results from the inversion are interpreted in the framework of the iranian present day tectonism full exploitation of dense 3 d coseismic surface deformation using sar data even for moderate earthquakes should facilitate distinguishing between different interpretations of the mechanical properties of seismically active areas and within the inherent ambiguity of the geophysical inversion solutions

emergence of striation patterns in acoustic signals reflected from dynamic surface waves a striation pattern can emerge in high frequency acoustic signals interacting with dynamic surface waves the striation pattern is analyzed using a ray tracing algorithm for both a sinusoidal and a rough surface with a source or receiver close to the surface it is found that part of the surface on either side of the specular reflection point can be illuminated by rays resulting in time varying later arrivals in channel impulse response that form the striation pattern in contrast to wave focusing associated with surface wave crests the striation occurs due to reflection off convex sections around troughs simulations with a sinusoidal surface show both an upward advancing and downward retreating striation patterns that depend on the surface wave traveling direction and the location of the illuminated area in addition the striation length is determined mainly by the depth of the source or receiver whichever is closer in range to the illuminated region even with a rough surface the striation emerges in both directions however broadband 7 13 khz simulations in shallow water indicate that the longer striation in one direction is likely pronounced against a quiet noise background as observed from at sea experimental data

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

three dimensional tracking of cuvier s beaked whales echolocation sounds using nested hydrophone arrays cuvier s beaked whales ziphius cavirostris were tracked using two volumetric small aperture 1 m element spacing hydrophone arrays embedded into a large aperture 1 km element spacing seafloor hydrophone array of five nodes this array design can reduce the minimum number of nodes that are needed to record the arrival of a strongly directional echolocation sound from 5 to 2 while providing enough time differences of arrivals for a three dimensional localization without depending on any additional information such as multipath arrivals to illustrate the capabilities of this technique six encounters of up to three cuvier s beaked whales were tracked over a two month recording period within an area of 20 km 2 in the southern california bight encounter periods ranged from 11 min to 33 min cuvier s beaked whales were found to reduce the time interval between echolocation clicks while alternating between two inter click interval regimes during their descent towards the seafloor maximum peak to peak source levels of 179 and 224 db re 1 pa 1 m were estimated for buzz sounds and on axis echolocation clicks directivity index 30 db respectively source energy spectra of the on axis clicks show significant frequency components between 70 and 90 khz in addition to their typically noted fm upsweep at 40 60 khz

the 20 hz signals of finback whales balaenoptera physalus the 20 hz signals of finback whales balaenoptera physalus were analyzed from more than 25 years of recordings at a variety of geographic locations on near surface hydrophones close to whales and on deep hydrophone systems these signals were composed of 1 s pulses of sinusoidal waveform with downward sweeping frequency from approximately 23 to 18 hz at variable source levels up to 186 db re 1 pa at 1 m usually with slightly lower levels for the pulses at the beginning and end of sequences these 20 hz pulses were produced in signal bouts separated by more than 2 h lasting as long as 32 5 h bouts were composed of regularly repeated pulses at intervals of 7 26 s typically either at one nominal pulse rate or at two alternating doublet pulse intervals signal bouts were interrupted by rests of 1 20 min at roughly 15 min intervals and by irregular gaps lasting between 20 and 120 min the distribution of these signals throughout the year and their temporal sequence were analyzed from the cont

evidence of harmonic tremor from a submarine volcano detected across the pacific ocean basin 1 since the 1950s seismic activity associated with submarine volcanic eruptions has been detected throughout the pacific ocean basin using hydroacoustic methods however narrowband harmonic tremor with multiple overtones typically associated with subaerial volcanic eruptions has not commonly been observed this paper presents a series of recently recorded hydroacoustic signals that originated in the volcano islands arc south of japan a region that frequently experiences submarine eruptions the signals are characterized by a narrowband long duration high amplitude fundamental centered at 10 hz with three harmonics at 20 30 and 40 hz and are consistent with harmonic tremor signals observed using traditional seismic methods at active subaerial volcanoes throughout the world these hydroacoustic signals were detected 21 different times over the period from april 1998 through december 1999 typically lasting from several days to several weeks after a 6 month hiatus the signals were detected 26 more times from june 2000 through august 2001 the signals are qualitatively interpreted as a result of resonance of a magma gas mixture within a large chamber conduit near the surface of a shallow 1 km submarine volcanic edifice allowing for efficient release of acoustic energy into the ocean sound channel during periods of peak energy radiation the tremor could be clearly detected on hydrophones in the western aleutians hawaii west coast of the united states and eastern equatorial pacific and was detected by the french polynesian seismic network covering a maximum distance of 14 000 km

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

coseismic and postseismic deformation estimation of the 2011 tohoku earthquake in kanto region japan using insar time series analysis and gps abstract we propose a methodology using interferometric synthetic aperture radar insar time series analysis and a single gps station to estimate the coseismic and postseismic crustal deformations in the kanto region japan which has been affected by the 2011 tohoku earthquake the proposed methodology depends on choosing a proper deformation trend s to accurately describe the earthquake deformation signature by studying the deformation time series of a single gps station the modeled deformation trend is subtracted from the unwrapped phase maps to separate the main deformation signature from the imposed errors some deformation components not described by the model s will leak to the residual phase maps which will be subjected to temporal and spatial filtering the final corrected unwrapped phase maps are estimated by restoring the modeled deformation trend to the filtered residual phase maps and finally the deformation time series is estimated using a least squares technique the proposed methodology was designed to retrieve complex and fine surface deformations in areas that have been affected by large dominating deformation signatures and contain at a least single gps station the methodology was tested using envisat asar c band images and validation was carried out using gps stations resulting in a mean rms error of 6 9 mm the estimated deformation time series shows a differential postseismic deformation pattern that can be attributed to an off boso peninsula motion triggered by the 2011 tohoku earthquake

seismogenic deformation structures in microbialites and mudstones silurian lockport dolomite northwestern ohio u s a syndepositional deformation structures are present at two different stratigraphic levels in the silurian lockport dolomite at a quarry in maumee ohio such structures are absent in this unit at twelve other quarries in northwestern ohio the structures at maumee present within stromatolites thrombolites and variably bedded mudstones include convolute layers homogenization of bedding and breccia clasts clasts of stromatolites boudinage structures normal reverse and thrust faults and discordant and concordant breccias the distribution of deformation structures within beds suggests substantial control from substrate rheology possibly resulting from differences in degrees of lithification and from variations in water content the extensive variety of syndepositional deformation structures juxtaposed evidence for nearly synchronous compression and dilation proximity 4 5 km of the structures to the largest fault in northwestern ohio the bowling green fault and the restricted geographic distribution of the deformation structures suggest seismic shaking as a probable mode of genesis similarities between features produced by seismogenic deformation of siliciclastic sediments and deformation features in the lockport dolomite provide additional evidence that the latter features are seismogenic it is postulated that two earthquakes one with a magnitude 5 caused the formation of the syndepositional deformation structures present in the youngest facies in the lockport dolomite at maumee quarry the bowling green fault 4 5 km west of maumee was a growth fault during formation of the lockport dolomite and is considered to have been the source of earthquakes that created the syndepositonal deformation structures in this unit at maumee quarry evidence from the lockport dolomite in northwestern ohio suggests that seismogenic deformation structures created by two earthquakes along the bowling green fault with magnitudes of 5 did not form in this unit over large areas i e all of northwestern ohio this evidence challenges the suggestion that syndepositional seismogenic deformation structures are always formed over a large area

frequency synchronization of blue whale calls near pioneer seamount vocalizations of blue whales were recorded with a cabled hydrophone array at pioneer seamount 50 miles off the california coast most calls occurred in repeated sequences of two call pairs a then b the b call is a frequency modulated tone highly repeatable in form and pitch a model of this sound is described which permits detecting very small frequency shifts b calls are found to be aligned in frequency to about one part in 180 this requires very fine pitch discrimination and control over calling frequency and suggests that synchronizing to a common frequency pattern carries some adaptive advantage some possibilities for acoustic sensing by whales requiring this fine frequency resolution are discussed

paleoliquefaction evidence for a strong holocene earthquake in south central indiana earthquake induced paleoliquefaction features in holocene sediments in south central indiana are evidence for strong shaking in the recent prehistoric past in an area where only infrequent low magnitude earthquakes have occurred during the 200 yr of the historic record distribution of liquefaction features and geotechnical analyses of liquefied sediments are the basis for estimating that an earthquake with a magnitude of 6 9 was centered near vallonia indiana radiometric archaeologic and stratigraphic relations bracket the event to between 3 7 ka and 4 2 ka b p evidence for a local source for strong shaking requires reassessment of earthquakes hazards in the southern indiana northern kentucky southwestern ohio area

passive acoustic monitoring using a towed hydrophone array results in identification of a previously unknown beaked whale habitat beaked whales are diverse and species rich taxa they spend the vast majority of their time submerged regularly diving to depths of hundreds to thousands of meters typically occur in small groups and behave inconspicuously at the surface these factors make them extremely difficult to detect using standard visual survey methods however recent advancements in acoustic detection capabilities have made passive acoustic monitoring pam a viable alternative beaked whales can be discriminated from other odontocetes by the unique characteristics of their echolocation clicks in 2009 and 2010 pam methods using towed hydrophone arrays were tested these methods proved highly effective for real time detection of beaked whales in the southern california bight scb and were subsequently implemented in 2011 to successfully detect and track beaked whales during the ongoing southern california behavioral response study the three year field effort has resulted in 1 the successful classification and tracking of cuvier s ziphius cavirostris baird s berardius bairdii and unidentified mesoplodon beaked whale species and 2 the identification of areas of previously unknown beaked whale habitat use identification of habitat use areas will contribute to a better understanding of the complex relationship between beaked whale distribution occurrence and preferred habitat characteristics on a relatively small spatial scale these findings will also provide information that can be used to promote more effective management and conservation of beaked whales in the scb a heavily used naval operation and training region

derivation of 3 d coseismic surface displacement fields for the 2011 mw 9 0 tohoku oki earthquake from insar and gps measurements

field occurrences of liquefaction induced features a primer for engineering geologic analysis of paleoseismic shaking discussed in this paper are the factors that control the typical manifestations of liquefaction that are found in continental field settings the factors are given mainly in terms of the local geologic field situation and the geotechnical properties there a meaningful interpretation of liquefaction based data for quantitative analysis of paleoseismic shaking requires understanding of both geologic and geotechnical roles in the mode of ground failure at a specific site recommendations are made for the size of the field area that must be searched for liquefaction effects in order to develop adequate data for engineering geologic geotechnical analyses of paleoseismicity the areal extent must be based on an appreciation that the tectonic situation can cause seismically induced liquefaction effects to form in some locales but not in others nearby even for a strong earthquake in the region our guidelines for the conduct of the field search and preliminary analysis of the data relate to three issues for which liquefaction features are especially useful in answering has there been strong holocene latest pleistocene shaking in the region where was the tectonic source and what was the strength of shaking understanding of the various factors that control the manifestations of liquefaction effects which we present in this paper is essential for developing credible answers to these questions

structural evolution of a world class epithermal orebody the martha hill deposit waihi new zealand we describe the complex structure in the highest now mined out levels of the world class martha hill gold silver deposit coromandel peninsula which is hosted in late miocene andesitic rocks a northeast striking block of rock 360 m long and up to 100 m wide was occupied by a complex vein network dominated by northeast striking gold silver lodes up to 30 m thick gold production was entirely from quartz veins the mineralization is embedded in the following geological history 1 deposition of the host volcanic rocks 2 initial tectonic fracturing 3 intrusion of clastic dikes and sills 4 start of hydrothermal alteration 5 main phase of faulting 6 main phase of veining 7 erosion and deep oxidation 8 11 deposition of further volcanic material including prominent rhyolites and formation of present topography veins occupied fractures but also followed a network of preexisting mostly normal faults with a small to medium amount of displacement faulting involved northwest southeast north south and east west extension implying complex 3 d strain clastic dikes of carbonaceous sandstone intruded during the faulting phase fault rocks were mostly brittle cataclasites or breccias but some clay rich zones displayed ductile structures many veins overprinted faults with a change from shear mode to opening mode deformation stockwork veins formed a mesh composed of two orthogonal sets one with northeast southwest and northwest southeast striking veins including the dominant mineralized lodes and the other with north south and east west striking veins although northwest striking veins were earliest during the main vein phase opening oscillated between all the vein directions with the two main lodes in the open pit area the martha and the welcome capturing most of the strain a variety of vein and breccia textures indicate repeated structurally controlled vein opening events that were associated with changes in the physical and chemical conditions of the mineralizing fluid a special concentration of structural features facilitated focusing of fluid flow to produce this world class deposit which contrasts with the less well endowed vein systems around it the overall tectonic control was dominated by northwest southeast extension and dip slip deformation the 3 d strain in this area was not only due to local interference of differently oriented structural features but also to the superposition of regional tectonic north northwest and northeast trends associated with migration of a subduction zone past the coromandel peninsula this demonstrates that structural control in an epithermal mineral deposit may originate from a number of different tectonic controls at different scales

sound source localization technique using a seismic streamer and its extension for whale localization during seismic surveys marine seismic surveys are under increasing scrutiny because of concern that they may disturb or otherwise harm marine mammals and impede their communications most of the energy from seismic surveys is low frequency so concerns are particularly focused on baleen whales extensive mitigation efforts accompany seismic surveys including visual and acoustic monitoring but the possibility remains that not all animals in an area can be observed and located one potential way to improve mitigation efforts is to utilize the seismic hydrophone streamer to detect and locate calling baleen whales this study describes a method to localize low frequency sound sources with data recoded by a streamer beamforming is used to estimate the angle of arriving energy relative to sub arrays of the streamer which constrains the horizontal propagation velocity to each sub array for a given trial location a grid search method is then used to minimize the time residual for relative arrival times along the streamer estimated by cross correlation results from both simulation and experiment are shown and data from the marine mammal observers and the passive acoustic monitoring conducted simultaneously with the seismic survey are used to verify the analysis

liquefaction evidence for strong earthquakes of holocene and latest pleistocene ages in the states of indiana and illinois usa abstract sand and gravel filled clastic dikes of seismic liquefaction origin occur throughout much of southern indiana and illinois nearly all of these dikes originated from prehistoric earthquakes centered in the study area in this area at least seven and probably eight strong prehistoric earthquakes have been documented as occurring during the holocene and at least one during the latest pleistocene the recognition of different earthquakes has been based mainly on timing of liquefaction in combination with the regional pattern of liquefaction effects but some have been recognized only by geotechnical testing at sites of liquefaction most paleo earthquakes presently recognized lie in indiana but equally as many may have occurred in illinois studies in illinois have not yet narrowly bracketed the age of clastic dikes at many sites which sometimes causes uncertainty in defining the causative earthquake but even in illinois the largest paleo earthquakes probably have been identified prehistoric magnitudes were probably as high as about moment magnitude m 7 5 this greatly exceeds the largest historic earthquake of m 5 5 centered in indiana or illinois the strongest paleo earthquakes struck in the vicinity of the concentration of strongest historic seismicity elsewhere paleo earthquakes on the order of m 6 7 have occurred even where there has been little or no historic seismicity both geologic and geotechnical methods of analysis have been essential for verification of seismic origin for the dikes and for back calculating prehistoric magnitudes methods developed largely as part of this study should be of great value in unraveling the paleoseismic record elsewhere

passive acoustic localization of the atlantic bottlenose dolphin using whistles and echolocation clicks a method for localization and tracking of calling marine mammals was tested under realistic field conditions that include noise multipath and arbitrarily located sensors experiments were performed in two locations using four and six hydrophones with captive atlantic bottlenose dolphins tursiops truncatus acoustic signals from the animals were collected in the field using a digital acoustic data acquisition system the data were then processed off line to determine relative hydrophone positions and the animal locations accurate hydrophone position estimates are achieved by pinging sequentially from each hydrophone to all the others a two step least squares algorithm is then used to determine sensor locations from the calibration data animal locations are determined by estimating the time differences of arrival of the dolphin signals at the different sensors the peak of a matched filter output or the first cycle of the observed waveform is used to determine arrival time of an echolocation click cross correlation between hydrophones is used to determine inter sensor time delays of whistles calculation of source location using the time difference of arrival measurements is done using a least squares solution to minimize error these preliminary experimental results based on a small set of data show that realistic trajectories for moving animals may be generated from consecutive location estimates

blue and fin whale call source levels and propagation range in the southern ocean blue balaenoptera musculus and fin whales b physalus produce high intensity low frequency calls which probably function for communication during mating and feeding the source levels of blue and fin whale calls off the western antarctic peninsula were calculated using recordings made with calibrated bottom moored hydrophones blue whales were located up to a range of 200km using hyperbolic localization and time difference of arrival the distance to fin whales estimated using multipath arrivals of their calls was up to 56km the error in range measurements was 3 8km using hyperbolic localization and 3 4km using multipath arrivals both species produced high intensity calls the average blue whale call source level was 189 3db re 1 pa 1m over 25 29hz and the average fin whale call source level was 189 4db re 1 pa 1m over 15 28hz blue and fin whale populations in the southern ocean have remained at low numbers for decades since they became protected using source level and detection range from

simulation of the supersar multi azimuth synthetic aperture radar imaging system for precise measurement of three dimensional earth surface displacement the supersar imaging system a novel multi azimuth synthetic aperture radar sar system capable of detecting earth surface deformation in three dimensions from a single satellite platform has recently been proposed in this paper we investigate the feasibility of detecting precise 3 d surface displacement measurements with the supersar imaging system using a point target simulation from this simulation we establish both a relationship between the interferometric sar phase and the across track displacement and a relationship between the multiple aperture interferometry phase and the along track displacement based on the supersar imaging geometry the theoretical uncertainties of the supersar measurement are analyzed in the across and along track directions and the theoretical accuracy of the 3 d displacement measurement from the supersar system is also investigated according to both the decorrelation and the squint and look angles in the case that the interferometric coherence is about 0 8 and that five effective looks are employed the theoretical 2 d measurement precision values are about 3 67 and 6 35 mm in the across and along track directions respectively and the theoretical 3 d measurement precision values for 3 d displacement are about 4 05 4 56 and 3 45 mm in the east north and up directions respectively the result of this study demonstrates that the supersar imaging system is capable of measuring the 3 d surface displacement in all directions with subcentimeter precision

ranging bowhead whale calls in a shallow water dispersive waveguide this paper presents the performance of three methods for estimating the range of broadband 50 500 hz bowhead whale calls in a nominally 55 m deep waveguide conventional mode filtering cmf synthetic time reversal str and triangulation the first two methods use a linear vertical array to exploit dispersive propagation effects in the underwater sound channel the triangulation technique used here while requiring no knowledge about the propagation environment relies on a distributed array of directional autonomous seafloor acoustics recorders dasars arranged in triangular grid with 7 km spacing this study uses simulations and acoustic data collected in 2010 from coastal waters near kaktovik alaska at that time a 12 element vertical array spanning the bottom 63 of the water column was deployed alongside a distributed array of seven dasars the estimated call location to array ranges determined from cmf and str are compared with dasar triangulation results for 19 whale calls the vertical array ranging results are generally within 10 of the dasar results with the str results providing slightly better agreement the results also indicate that the vertical array can range calls over larger ranges and with greater precision than the particular distributed array discussed here whenever the call locations are beyond the distributed array boundaries

effective beam pattern of the blainville s beaked whale mesoplodon densirostris and implications for passive acoustic monitoring the presence of beaked whales in mass strandings coincident with navy maneuvers has prompted the development of methods to detect these cryptic animals blainville s beaked whales mesoplodon densirostris produce distinctive echolocation clicks during long foraging dives making passive acoustic detection a possibility however performance of passive acoustic monitoring depends upon the source level beam pattern and clicking behavior of the whales in this study clicks recorded from digital acoustic tags dtags attached to four m densirostris were linked to simultaneous recordings from an 82 hydrophone bottom mounted array to derive the source level and beam pattern of the clicks as steps towards estimating their detectability the mean estimated on axis apparent source level for the four whales was 201 dbrms97 the mean 3 db beamwidth and directivity index estimated from sequences of clicks directed towards the far field hydrophones were 13 and 23 db respectively while searching for prey blainville s beaked whales scan their heads horizontally at a mean rate of 3 6 s over an angular range of some 10 thus while the di indicates a narrow beam the area of ensonification over a complete foraging dive is large given the combined effects of body and head movements associated with foraging

probabilistic seismic hazard assessment including site effects for evansville indiana and the surrounding region abstract evansville indiana is one of the closest large urban areas to both the new madrid seismic zone where large earthquakes occurred in 1811 1812 and the wabash valley seismic zone where there is evidence of several large prehistoric earthquakes in the last 14 000 yr for this reason evansville has been targeted as a priority region for urban seismic hazard assessment the probabilistic seismic hazard methodology used for the evansville region incorporates new information from recent surficial geologic mapping efforts as well as information on the depth and properties of near surface soils and their associated uncertainties the probabilistic seismic hazard calculation applied here follows the method used for the 2008 united states geological survey usgs national seismic hazard maps with modifications to incorporate estimates of local site conditions and their uncertainties in a completely probabilistic manner the resulting analysis shows strong local variations of acceleration with 2 probability of exceedance in 50 yr which are clearly correlated with variations in the thickness of unconsolidated soils above bedrock spectral accelerations at 0 2 s period range from 0 6 to 1 5 g values that are much greater than those of the usgs national seismic hazard map which assume b c site conditions with an average shear wave velocity of 760 m s in the top 30 m the presence of an ancient bedrock valley underlying the current ohio river flood plain strongly affects the spatial pattern of accelerations for 1 0 s spectral acceleration ground motions are significantly amplified due to deeper soils within this structure to a level comparable to that predicted by the national seismic hazard maps with d site conditions assumed for pga and 0 2 s spectral acceleration ground motions are significantly amplified outside this structure above the levels predicted by the national seismic hazard maps with uniform d site conditions assumed

estimating spatiotemporal ground deformation with improved persistent scatterer radar interferometry ast synthetic aperture radar interferometry has been applied widely in recent years to ground deformation monitoring although difficulties are often encountered when applying the technology among which the spatial and temporal decorrelation and atmospheric artifacts are the most prominent the persistent scatterer interferometric synthetic aperture radar ps insar technique has overcome some of the difficulties by focusing only on the temporally coherent radar targets in a time series of synthetic aperture radar sar images this paper presents an improved ps insar technique by introducing ps neighborhood networking and empirical mode decomposition emd approaches in the ps insar solution linear deformation rates and topographic errors are estimated based on a least squares method while the nonlinear deformation and atmospheric signals are computed by singular value decomposition and the emd method an area in phoenix az is used as a test site to determine its historical subsidence with 39 c band sar images acquired by european remote sensing 1 and 2 satellites from 1992 to 2000

acoustic tracking of sperm whales in the gulf of alaska using a two element vertical array and tags between 15 and 17 august 2010 a simple two element vertical array was deployed off the continental slope of southeast alaska in 1200 m water depth the array was attached to a vertical buoy line used to mark each end of a longline fishing set at 300 m depth close to the sound speed minimum of the deep water profile the buoy line also served as a depredation decoy attracting seven sperm whales to the area one animal was tagged with both a limpet dive depth transmitting satellite and bioacoustic b probe tag both tag datasets were used as an independent check of various passive acoustic schemes for tracking the whale in depth and range which exploited the elevation angles and relative arrival times of multiple ray paths recorded on the array analytical tracking formulas were viable up to 2 km range but only numerical propagation models yielded accurate locations up to at least 35 km range at beaufort sea state 3 neither localization approach required knowledge of the local bottom bathymetry the

paleoseismic features as indicators of earthquake hazards in north coastal san diego county california usa abstract new road cut and mass grading excavations in the north coastal area of san diego county california expose heretofore generally unrecognized probable late holocene tsunami deposits and paleoseismically deformed sediments remnant tsunami deposits occur up to 100 m in elevation around the margins of modern coastal lagoons and estuaries and combined with local mima mounds of possible sand blow origin provide indirect but compelling evidence for the late quaternary activity of onshore and offshore faults in the immediate study area probable paleoliquefaction features are regionally widespread and range from fissures filled with sediments derived from overlying marine terrace sand and soil to the more traditional sand filled injection dikes and sills lateral spreads and filled craterlets the source of most liquefied sediment is underlying tertiary bedrock sand and local quaternary marine terrace deposits a paleoseismic liquefaction origin rather than soft sediment loading is deduced for these features based on morphology internal stratigraphy field setting and near proximity to known seismogenic sources some paleoseismic events impacted late holocene indian middens and burial sites the last seismic event probably occurred within the past 1 to 3 ka and possibly even records the historic earthquakes of either november 22 1800 or may 27 1862 the liquefaction features also affect marine terrace sediments tens of meters above modern regional water levels inferentially recording paleoseismic events in this mediterranean type climatic region during winter rains when high level perched water saturates the several meter thick source sediments based on their regional extent the paleoseismic features were likely caused by m 7 tectonic events inferentially generated by the nearby offshore newport inglewood rose canyon fault system or possibly by smaller recently exposed related and localized faults accordingly the seismic hazard of the north coastal area of san diego county may be substantially higher than previously assumed and hence of concern owing to the rapid ongoing and projected population increase

sounds and source levels from bowhead whales off pt barrow alaska sounds were recorded from bowhead whales migrating past pt barrow ak to the canadian beaufort sea they mainly consisted of various low frequency 25 to 900 hz moans and well defined sound sequences organized into song 20 5000 hz recorded with our 2 46 km hydrophone array suspended from the ice songs were composed of up to 20 repeated phrases mean 10 which lasted up to 146 s mean 66 3 several bowhead whales often were within acoustic range of the array at once but usually only one sang at a time vocalizations exhibited diurnal peaks of occurrence 0600 0800 1600 1800 h sounds which were located in the horizontal plane had peak source spectrum levels as follows 44 moans 129 178 db re 1 pa 1 m median 159 3 garglelike utterances 152 155 and 169 db 33 songs 158 189 db median 177 all presumably from different whales based on ambient noise levels measured total propagation loss and whale sound source levels our detection of whale sounds was theoretically noise limited

application of dinsar gps optimization for derivation of fine scale surface motion maps of southern california a method based on random field theory and gibbs markov random fields equivalency within bayesian statistical framework is used to derive 3 d surface motion maps from sparse global positioning system gps measurements and differential interferometric synthetic aperture radar dinsar interferogram in the southern california region the minimization of the gibbs energy function is performed analytically which is possible in the case when neighboring pixels are considered independent the problem is well posed and the solution is unique and stable and not biased by the continuity condition the technique produces a 3 d field containing estimates of surface motion on the spatial scale of the dinsar image over a given time period complete with error estimates significant improvement in the accuracy of the vertical component and moderate improvement in the accuracy of the horizontal components of velocity are achieved in comparison with the gps data alone the method can be expanded to account for other available data sets such as additional interferograms lidar or leveling data in order to achieve even higher accuracy

the 18 june 2002 caborn indiana earthquake reactivation of ancient rift in the wabash valley seismic zone the 18 june 2002 caborn indiana earthquake m w 4 6 occurred on a steeply dipping fault at a depth of about 18 km regional and teleseismic waveform data were used to obtain an accurate hypocenter with uncertainties better than about 2 km in both vertical and horizontal directions the source mechanism determined from regional waveform analysis is predominantly strike slip along near vertical nodal planes dips 82 and 84 striking 28 and 297 the nearly horizontal p axis trends 252 and plunges 10 the close proximity of the epicenter to the trace of the compound caborn fault and good agreement between the strike and dip of that fault and the source mechanism of the 2002 event suggests that the earthquake may have occurred on that fault most of the wabash valley faults as mapped from the shallow subsurface data extend into the precambrian basement to at least 7 km depth without significantly changing their orientation the june 2002 event at 18 km depth and the south central illinois earthquake on 9 november 1968 m w 5 3 which occurred at 25 km depth suggest that the seismogenic depth in the wabash valley seismic zone extends down to at least 18 km depth this earthquake is unique because it is the largest instrumented event to date that is clearly located within the area spanned by the wabash valley fault system its focal mechanism vertical strike slip faulting at depth may suggest that buried faults associated with a possible precambrian rift system are being reactivated by the contemporary east east northeast trending regional horizontal compressive stress

3d displacement maps of the 2009 l aquila earthquake italy by applying the sistem method to gps and dinsar data terra nova 25 79 85 2013 abstract we present an application of the novel sistem approach to obtain the dense 3d ground deformation pattern produced by the april 6 2009 mw 6 3 l aquila earthquake this event characterized by a sw dipping normal fault with thousands of foreshocks and aftershocks located in the depth range 5 15 km is the most destructive to have struck the abruzzo region since the major 1703 seismic sequence the surface deformation revealed by the sistem through the integration of gps with interferometric measurements from the envisat and alos satellites shows a deformed area extending towards se along the aterno valley in agreement with seismological and other geodetic observations we inverted the sistem results using an optimization algorithm based on the genetic algorithm providing an accurate spatial characterization of ground deformation our results improve previous kinematic solutions for the paganica fault and allow identification of additional faults that have contributed to the observed complex ground deformation pattern

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

range estimation of bowhead whale balaena mysticetus calls in the arctic using a single hydrophone bowhead whales generate low frequency calls in shallow water arctic environments whose dispersive propagation characteristics are well modeled by normal mode theory as each mode propagates with a different group speed a call s range can be inferred by the relative time frequency dispersion of the modal arrivals traditionally at close ranges modal arrivals are separated using synchronized hydrophone arrays here a nonlinear signal processing method called warping is used to filter the modes on just a single hydrophone the filtering works even at relatively short source ranges where distinct modal arrivals are not separable in a conventional spectrogram however this warping technique is limited to signals with monotonically increasing or decreasing frequency modulations a relatively common situation for bowhead calls once modal arrivals have been separated the source range can be estimated using conventional modal dispersion techniques with the original source signal structure being recovered as a by product twelve bowhead whale vocalizations recorded near kaktovik alaska in 2010 with signal to noise ratios between 6 and 23 db are analyzed and the resulting single receiver range estimates are consistent with those obtained independently via triangulation from widely distributed vector sensor arrays geoacoustic inversions for each call are necessary in order to obtain the correct ranges

beaked whale and dolphin tracking using a multichannel autonomous acoustic recorder to track highly directional echolocation clicks from odontocetes passive hydrophone arrays with small apertures can be used to receive the same high frequency click on each sensor a four hydrophone small aperture array was coupled to an autonomous acoustic recorder and used for long term tracking of high frequency odontocete sounds the instrument was deployed in the spring of 2009 offshore of southern california in a known beaked whale and dolphin habitat at about 1000 m depth the array was configured as a tetrahedron with approximately 0 5 m sensor spacing time difference of arrival measurements between the six sensor pairs were used to estimate three dimensional bearings to sources both near seafloor beaked whales and near sea surface dolphins were tracked the tracks observed using this technique provide swimming and diving behavioral information for free ranging animals using a single instrument furthermore animal detection ranges were derived allowing for estimation of detection probability functions

comparison between visual and passive acoustic detection of finless porpoises in the yangtze river china recently sonar signals and other sounds produced by cetaceans have been used for acoustic detection of individuals and groups in the wild however the detection probability ascertained by concomitant visual survey has not been demonstrated extensively the finless porpoises neophocaena phocaenoides have narrow band and high frequency sonar signals which are distinctive from background noises underwater sound monitoring with hydrophones b k8103 placed along the sides of a research vessel concurrent with visual observations was conducted in the yangtze river from wuhan to poyang lake in 1998 in china the peak to peak detection threshold was set at 133 db re 1 mu pa with this threshold level porpoises could be detected reliably within 300 m of the hydrophone in a total of 774 km cruise 588 finless porpoises were sighted by visual observation and 44 864 ultrasonic pulses were recorded by the acoustical observation system the acoustic monitoring system could detect the presence of the finless porpoises 82 of the time a false alarm in the system occurred with a frequency of 0 9 the high frequency acoustical observation is suggested as an effective method for field surveys of small cetaceans which produce high frequency sonar signals c 2001 acoustical society of america

soft sediment deformation at the base of the neoproterozoic puga cap carbonate southwestern amazon craton brazil confirmation of rapid icehouse to greenhouse transition in snowball earth stratigraphic and isotopic data identify the lower 45 m of the araras group on the southwest margin of the amazon craton as a neoproterozoic platform cap carbonate deposited below wave base upon varanger glacial diamictites of the puga formation the basal beds consist of moderately deep water pinkish dolomudstone with stratiform to wavy fenestral microbialites locally cut by tube like structures and fenestral nonmicrobial planar laminites with tepee like features above the basal carbonates are deep water bituminous lime mudstones with alternating thin calcite crusts and lime mudstone laminae commonly disrupted by calcite crystal fans pseudomorphs after aragonite the basal contact of the puga cap exhibits soft sediment deformational structures principally load casts that are here attributed to rebound induced seismicity acting upon both recently deposited carbonate sediments and underlying unconsolidated diamictite these features constitute the first clearly recognized sedimentological evidence for the rapid change from icehouse to greenhouse conditions as postulated in the snowball earth model of neoproterozoic glaciation

use of liquefaction induced features for paleoseismic analysis an overview of how seismic liquefaction features can be distinguished from other features and how their regional distribution and properties of source sediment can be used to infer the location and strength of holocene paleo earthquakes abstract liquefaction features can be used in many field settings to estimate the recurrence interval and magnitude of strong earthquakes through much of the holocene these features include dikes craters vented sand sills and laterally spreading landslides the relatively high seismic shaking level required for their formation makes them particularly valuable as records of strong paleo earthquakes this state of the art summary for using liquefaction induced features for paleoseismic interpretation and analysis takes into account both geological and geotechnical engineering perspectives the driving mechanism for formation of the features is primarily the increased pore water pressure associated with liquefaction of sand rich sediment the role of this mechanism is often supplemented greatly by the direct action of seismic shaking at the ground surface which strains and breaks the clay rich cap that lies immediately above the sediment that liquefied discussed in the text are the processes involved in formation of the features as well as their morphology and characteristics in field settings whether liquefaction occurs is controlled mainly by sediment grain size sediment packing depth to the water table and strength and duration of seismic shaking formation of recognizable features in the field generally requires a low permeability cap above the sediment that liquefied field manifestations are controlled largely by the severity of liquefaction and the thickness and properties of the low permeability cap criteria are presented for determining whether observed sediment deformation in the field originated by seismically induced liquefaction these criteria have been developed mainly by observing historic effects of liquefaction in varied field settings the most important criterion is that a seismic liquefaction origin requires widespread regional development of features around a core area where the effects are most severe in addition the features must have a morphology that is consistent with a very sudden application of a large hydraulic force this article discusses case studies in widely separated and different geological settings coastal south carolina the new madrid seismic zone the wabash valley seismic zone and coastal washington state these studies encompass most of the range of settings and the types of liquefaction induced features likely to be encountered anywhere the case studies describe the observed features and the logic for assigning a seismic liquefaction origin to them also discussed are some types of sediment deformations that can be misinterpreted as having a seismic origin two independent methods for estimating prehistoric magnitude are discussed briefly one method is based on determination of the maximum distance from the epicenter over which liquefaction induced effects have formed the other method is based on use of geotechnical engineering techniques at sites of marginal liquefaction in order to bracket the peak accelerations as a function of epicentral distance these accelerations can then be compared with predictions from seismological models

estimation of 3 d surface displacement based on insar and deformation modeling a new approach is presented for mapping 3 d surface displacement caused by subsurface fluid volumetric change based on 1 d interferometric synthetic aperture radar insar line of sight measurements and surface deformation modeling the relationship between surface deformation and source fluid volumetric change is modeled according to elastic half space theory a distinctive advantage of the proposed approach is that it effectively extends the capability of the sun synchronous orbit side looking synthetic aperture radar that has been essentially only able to measure 1 d displacements accurately or at most 2 d displacements when insar measurements from more than one orbit or platform are combined experimental studies are carried out with both simulated and real data sets to test the performance of the method the results have demonstrated that the approach works very well

acoustic survey for marine mammal occurrence and distribution off east antarctica 30 80 e in january february 2006 abstract a large scale systematic acoustic survey for whales and seals in eastern antarctic waters was conducted in january february 2006 during the broke west survey of southern ocean waters between 30 and 80 e longitude an acoustic survey was conducted to complement a traditional visual survey for marine mammal occurrence and distribution as part of the survey 145 difar sonobuoys were deployed every 30 of latitude on north south transects and prior to ctd stations on the initial east west transect underwater sound was analyzed for 70 minute samples from each sonobuoy blue whales were the most commonly recorded species identified at 55 of the sonobuoy deployment sites other species recorded include sperm 46 sites fin 14 humpback 2 and sei 3 whales and leopard 11 and ross 17 seals large numbers of blue and sperm whales and all ross seals were detected on the westernmost two transects which were the only transects of the survey with relatively extensive sea ice remaining off the continental shelf large numbers of blue whales were also detected in the more eastern waters of the survey off the prydz bay region while two detections of pygmy blue whales represent the farthest south these whales have been recorded of the relatively few fin whale detections most occurred in more northerly waters fin whale vocalizations from this region were distinctly different than those recorded elsewhere around antarctica suggesting acoustic recordings may be useful to delineate regional or stock boundaries of this species previously undescribed sounds were attributed to ross seals acoustic detections of these and leopard seal sounds indicate these animals venture further from their traditionally described distributions with vocalizing leopard seals occurring much further north than might be expected overall the results of the sonobuoy survey provide a measure of each species relative spatial distribution over the survey area based on acoustic detections and when combined with the results of the visual survey will provide a comprehensive view of marine mammal distribution throughout the region during the broke west survey

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

underwater passive acoustic localization of pacific walruses in the northeastern chukchi sea this paper develops and applies a linearized bayesian localization algorithm based on acoustic arrival times of marine mammal vocalizations at spatially separated receivers which provides three dimensional 3d location estimates with rigorous uncertainty analysis to properly account for uncertainty in receiver parameters 3d hydrophone locations and synchronization times and environmental parameters water depth and sound speed correction these quantities are treated as unknowns constrained by prior estimates and prior uncertainties unknown scaling factors on both the prior and arrival time uncertainties are estimated by minimizing akaike s bayesian information criterion a maximum entropy condition maximum a posteriori estimates for sound source locations and times receiver parameters and environmental parameters are calculated simultaneously using measurements of arrival times for direct and interface reflected acoustic paths posterior uncertainties for all unknowns incorporate both arrival time and prior uncertainties monte carlo simulation results demonstrate that for the cases considered here linearization errors are small and the lack of an accurate sound speed profile does not cause significant biases in the estimated locations a sequence of pacific walrus vocalizations recorded in the chukchi sea northwest of alaska is localized using this technique yielding a track estimate and uncertainties with an estimated speed comparable to normal walrus swim speeds

seismotectonic implications of sand blows in the southern mississippi embayment we explore seismically induced sand blows from the southern mississippi embayment and their implications in resolving the question of near or distal epicentral source region this was accomplished using aerial photography field excavations and cone penetration tests our analysis shows that three sand blow fields exhibit a distinct chronology of strong ground motion for the southern embayment 1 the ashley county arkansas sand blow field near the arkansas louisiana state border experienced four holocene sand venting episodes 2 to the north the desha county field experienced at least three episodes of liquefaction and 3 the lincoln jefferson counties field experienced at least one episode cone penetration tests cpt conducted in and between the sand blow fields suggest that the fields may not be distal liquefaction associated with new madrid seismic zone earthquakes but rather are likely associated with strong earthquakes on local faults this conclusion is consistent with the differences in timing of the southern embayment sand venting episodes and those in the new madrid seismic zone these results suggest that active tectonism and strong seismicity in intraplate north america may not be localized at isolated weak spots but rather widespread on fault systems that are favorably oriented for slip in the contemporary stress field

estimating cetacean population density using fixed passive acoustic sensors an example with blainville s beaked whales methods are developed for estimating the size density of cetacean populations using data from a set of fixed passive acoustic sensors the methods convert the number of detected acoustic cues into animal density by accounting for i the probability of detecting cues ii the rate at which animals produce cues and iii the proportion of false positive detections additional information is often required for estimation of these quantities for example from an acoustic tag applied to a sample of animals methods are illustrated with a case study estimation of blainville s beaked whale density over a 6day period in spring 2005 using an 82 hydrophone wide baseline array located in the tongue of the ocean bahamas to estimate the required quantities additional data are used from digital acoustic tags attached to five whales over 21 deep dives where cues recorded on some of the dives are associated with those received on the fixed hydrophones estimated density was 25 3 or 22 5 animals 1000km2 depend

correcting atmospheric effects on insar with meris water vapour data and elevation dependent interpolation model summary the propagation delay when radar signals travel from the troposphere has been one of the major limitations for the applications of high precision repeat pass interferometric synthetic aperture radar insar in this paper we first present an elevation dependent atmospheric correction model for advanced synthetic aperture radar asar the instrument aboard the envisat satellite interferograms with medium resolution imaging spectrometer meris integrated water vapour iwv data then using four asar interferometric pairs over southern california as examples we conduct the atmospheric correction experiments with cloud free meris iwv data the results show that after the correction the rms differences between insar and gps have reduced by 69 6 per cent 29 per cent 31 8 per cent and 23 3 per cent respectively for the four selected interferograms with an average improvement of 38 4 per cent most importantly after the correction six distinct deformation areas have been identified that is long beach santa ana basin pomona ontario san bernardino and elsinore basin with the deformation velocities along the radar line of sight los direction ranging from 20 mm yr 1 to 30 mm yr 1 and on average around 25 mm yr 1 and santa fe springs and wilmington with a slightly low deformation rate of about 10 mm yr 1 along los finally through the method of stacking we generate a mean deformation velocity map of los angeles over a period of 5 yr the deformation is quite consistent with the historical deformation of the area thus using the cloud free meris iwv data correcting synchronized asar interferograms can significantly reduce the atmospheric effects in the interferograms and further better capture the ground deformation and other geophysical signals

shallow seismic reflection profiles and geological structure in the benton hills southeast missouri abstract during late may and early june of 1993 we conducted two shallow high resolution seismic reflection surveys mini sosie method across the southern escarpment of the benton hills segment of crowleys ridge the reflection profiles imaged numerous post late cretaceous faults and folds we believe these faults may represent a significant earthquake source zone the stratigraphy of the benton hills consists of a thin less than about 130 m sequence of mostly unconsolidated cretaceous tertiary and quaternary sediments which uncomfortably overlie a much thicker section of paleozoic carbonate rocks the survey did not resolve reflectors within the upper 75 100 ms of two way travel time about 60 100 m which would include all of the tertiary and quaternary and most of the cretaceous however the paleozoic cretaceous unconformity pz produced an excellent reflection and locally a shallower reflector within the cretaceous k was resolved no coherent reflections below about 200 ms of two way travel time were identified numerous faults and folds which clearly offset the paleozoic cretaceous unconformity reflector were imaged on both seismic reflection profiles many structures imaged by the reflection data are coincident with the surface mapped locations of faults within the cretaceous and tertiary succession two locations show important structures that are clearly complex fault zones the english hill fault zone striking n30 35 e is present along line 1 and is important because earlier workers indicated it has pleistocene loess faulted against eocene sands the commerce fault zone striking n50 e overlies a major regional basement geophysical lineament and is present on both seismic lines at the southern margin of the escarpment the fault zones imaged by these surveys are 30 km from the area of intense microseismicity in the new madrid seismic zone nmsz if these are northeast and north northeast oriented fault zones like those at thebes gap they are favorably oriented in the modern stress field to be reactivated as right lateral strike slip faults currently earthquake hazards assessments are most dependent upon historical seismicity and there are little geological data available to evaluate the earthquake potential of fault zones outside of the nmsz we anticipate that future studies will provide evidence that seismicity has migrated between fault zones well beyond the middle mississippi valley the potential earthquake hazards represented by faults outside the nmsz may be significant

three dimensional passive acoustic tracking of sperm whales physeter macrocephalus in ray refracting environments a wide aperture towed passive acoustic array is used to obtain ranges and depths of acoustically active sperm whales in the gulf of mexico in june 2004 by extending a technique previously reported thode j acoust soc am 116 245 253 2004 to explicitly account for ray refraction effects arising from a depth dependent sound speed profile under this expanded approach three quantities are measured from an impulsive sound the time difference between direct path arrivals on a forward and rear subarray the time difference between the direct and surface reflected paths on the rear subarray and the acoustic bearing measured on the rear subarray these quantities combined with independent measurements of hydrophone depths and cable inclination are converted into range depth position fixes by implementing an efficient numerical procedure that uses a ray tracing code to account for ray refraction effects caused by depth dependent sound speed profiles analytic expressions that assume a constant waterb

long range acoustic detection and localization of blue whale calls in the northeast pacific ocean analysis of acoustic signals recorded from the u s navy s sound surveillance system sosus was used to detect and locate blue whale balaenoptera musculus calls offshore in the northeast pacific the long low frequency components of these calls are characteristic of calls recorded in the presence of blue whales elsewhere in the world mean values for frequency and time characteristics from field recorded blue whale calls were used to develop a simple matched filter for detecting such calls in noisy time series the matched filter was applied to signals from three different sosus arrays off the coast of the pacific northwest to detect and associate individual calls from the same animal on the different arrays a u s navy maritime patrol aircraft was directed to an area where blue whale calls had been detected on sosus using these methods and the presence of a vocalizing blue whale was confirmed at the site with field recordings from sonobuoys

tracking dolphin whistles using an autonomous acoustic recorder array dolphins are known to produce nearly omnidirectional whistles that can propagate several kilometers allowing these sounds to be localized and tracked using acoustic arrays during the fall of 2007 a km scale array of four autonomous acoustic recorders was deployed offshore of southern california in a known dolphin habitat at 800 m depth concurrently with the one month recording a fixed point marine mammal visual survey was conducted from a moored research platform in the center of the array providing daytime species and behavior visual confirmation the recordings showed three main types of dolphin acoustic activity during distinct times primarily whistling during daytime whistling and clicking during early night and primarily clicking during late night tracks from periods of daytime whistling typically were tightly grouped and traveled at a moderate rate in one example with visual observations traveling common dolphins delphinus sp were tracked for about 10 km with an average speed of 2 5

echolocation clicks of free ranging cuvier s beaked whales ziphius cavirostris strandings of beaked whales of the genera ziphius and mesoplodon have been reported to occur in conjunction with naval sonar use detection of the sounds from these elusive whales could reduce the risk of exposure but descriptions of their vocalizations are at best incomplete this paper reports quantitative characteristics of clicks from deep diving cuvier s beaked whales ziphius cavirostris using a unique data set two whales in the ligurian sea were simultaneously tagged with sound and orientation recording tags and the dive tracks were reconstructed allowing for derivation of the range and relative aspect between the clicking whales at depth the whales produced trains of regular echolocation clicks with mean interclick intervals of 0 43 s 0 09 and 0 40 s 0 07 the clicks are frequency modulated pulses with durations of 200 s and center frequencies around 42 khz 10 db bandwidths of 22 khz and q3 db of 4 the sound beam is narrow with an estimated directionality index of more than 25 db

an elliptical model for deformation due to groundwater fluctuations historically surface subsidence as a result of subsurface groundwater fluctuations have produced important and at times catastrophic effects whether natural or anthropogenic over the past 30 years numerical and analytical techniques for the modeling of this surface deformation based upon elastic and poroelastic theory have been remarkably successful in predicting the magnitude of that deformation le mouelic and adragna in geophys res lett 29 1853 2002 in this work we have extended the formula for a circular shaped aquifer geertsma in j petroleum tech 25 734 744 1973 to a more realistic elliptical shape we have improved the accuracy of the approximation by making use of the cross terms of the expansion for the elliptic coordinates in terms of the eccentricity e and the mean anomaly angle m widely used in astronomy results of a number of simulations in terms of e and m developed from the transcendental kepler equation are encouraging giving realistic values for the elliptical approximation of the vertical deformation due to groundwater change finally we have applied the algorithm to modeling of groundwater in southern california

three dimensional surface motion maps estimated from combined interferometric synthetic aperture radar and gps data 1 we provide a technique to efficiently produce high resolution three dimensional surface motion maps by combining information about the motion of the earth s surface from interferometric observations of synthetic aperture radar images and repeated global positioning system gps geodetic measurements unwrapped interferograms showing pixel wise change in range from ground to satellite and sparse values of threedimensional movements are required as input the problem of finding the full threedimensional motion field is separated into two two dimensional problems initially the vertical component of the deformation field and its horizontal component in the look direction of the satellite are found later the look direction component is resolved into north and east components initial values for the motion fields are assigned to each pixel of interferograms from interpolation of available gps observations these values are then updated and optimized by comparison with the interferograms and the gps observations an additional constraint is an assumption of a smoothly varying motion field markov random field based regularization and simulated annealing algorithm are used for the optimization the technique is applied to create surface motion maps for the reykjanes peninsula sw iceland index terms 0933 exploration geophysics remote sensing 0910 exploration geophysics data processing 1206 geodesy and gravity crustal movements interplate 8155 8150 tectonophysics evolution of the earth plate boundary general 3040 8155 tectonophysics evolution of the earth plate motions general keywords remote sensing motion maps deformation data fusion interferometry gps

tracking fin whales in the northeast pacific ocean with a seafloor seismic network ocean bottom seismometer obs networks represent a tool of opportunity to study fin and blue whales a small obs network on the juan de fuca ridge in the northeast pacific ocean in 2 3 km of water recorded an extensive data set of 20 hz fin whale calls an automated method has been developed to identify arrival times based on instantaneous frequency and amplitude and to locate calls using a grid search even in the presence of a few bad arrival times when only one whale is calling near the network tracks can generally be obtained up to distances of 15 km from the network when the calls from multiple whales overlap user supervision is required to identify tracks the absolute and relative amplitudes of arrivals and their three component particle motions provide additional constraints on call location but are not useful for extending the distance to which calls can be located the double difference method inverts for changes in relative call locations using differences in residuals for pairs of nearby calls recorded on a common station the method significantly reduces the unsystematic component of the location error especially when inconsistencies in arrival time observations are minimized by cross correlation

soft sediment deformation structures in late miocene pleistocene sediments on the pediment of the matra hills visonta atkar verseg cryoturbation load structures or seismites abstract the studied area built up by silty clayey and partly sandy sediments and paleosols lies on the tectonically active northern margins of the pannonian basin wavy sagging load casts can be observed in the upper part of the late miocene alluvial complex and larger scale sagging load casts flame structures drops and pillows detected in its quaternary cover were studied in detail in order to understand the origins of soft sediment deformation which characterized this young sedimentary suite sedimentological paleopedological and mineralogical observations suggest that 1 one of the reasons for the soft sediment deformation might have been the relatively low cohesive strength of the predominantly smectitic sediment covering a gentle slope similar to the actual landscape 2 on such a surface the down slope gravitational component of the mud blanket might easily have been sufficient to overcome its cohesive strength 3 frost action traceable in the studied formations might also have contributed to the observed deformation particularly along the eroded top of the late miocene sediments combined evidence from field observations and laboratory analyses support the idea that liquefaction fluidization was of prime importance in bringing about the observed structures in conclusion two alternative quaternary holocene scenarios are proposed which might have resulted in the unusual behaviour of the sediments paleosols one is a seismic event the other is the combined effect of freeze thaw cycles and of the sloping foothill position which might have resulted in episodic downslope transport and the associated deformation of the eroded soil material when its water content surpassed a certain threshold we accept that the anomalous abundance of soft sediment deformation in this marginal position may be causally related to paleo earthquakes but the obvious complexity of the phenomenon requires caution in case the proposed scenarios would not have been alternatives but acted simultaneously the analysed phenomena were to be interpreted as the joint results of tectonics and climate change

seismically induced soft sediment deformation structures associated with the magallanes fagnano fault system isla grande de tierra del fuego argentina abstract in this paper evidence of paleoearthquake induced soft sediment deformation structures associated with the magallanes fagnano fault system in the isla grande de tierra del fuego southern argentina has been identified well preserved soft sediment deformation structures were found in a holocene sequence of the udaeta pond these structures were analyzed in terms of their geometrical characteristics deformation mechanism driving force system and possible trigger agent they were also grouped in different morphological types sand dykes convolute lamination load structures and faulted soft sediment deformation features udaeta a small pond in argentina tierra del fuego is considered a quaternary pull apart basin related to the magallanes fagnano fault system the recognition of these seismically induced features is an essential tool for paleoseismic studies since the three main urban centers in the tierra del fuego province of argentina ushuaia rio grande and tolhuin have undergone an explosive growth in recent years the results of this study will hopefully contribute to future analyses of the seismic risk of the region

evolution of the late cretaceous dadaepo basin se korea in response to oblique subduction of the proto pacific izanagi kula or pacific plate abstract the dadaepo basin is a small late cretaceous sedimentary basin in se korea located on the eastern margin of asia the basin is an isolated extensional basin situated between the nne striking yangsan and dongnae faults the basin fill sediments named the dadaepo formation consist of channelized conglomerates and sandstones intercalated with dominantly purple mudstones in the lower part the upper part is dominated by fine to coarse grained tuffaceous sandstones and olive to dark gray mudstones with abundant volcanic interbeds the formation unconformably overlies dacitic rocks dated at ca 94 ma and is overlain by basaltic andesite dated at ca 69 ma ar ar ages the overall configuration of the strata of the dadaepo formation indicates syndepositional tilting of the basin floor to the north northeast a number of outcrop scale faults are observed in the basin fill sediments of which the majority are nw striking normal faults including syndepositional growth faults the orientations of mafic magmatic and clastic dikes interpreted as being approximately contemporaneous with the deposition of the dadaepo formation are also nearly parallel to the strikes of outcrop scale normal faults all these extensional structures consistently indicate ne sw extension of the basin and obliquely intersect the basin bounding yangsan and dongnae faults at angles of 40 60 it is thus concluded that the dadaepo formation was deposited in a pull apart basin that subsided as a result of nne striking sinistral strike slip faulting in the southeastern part of the korean peninsula during the campanian late cretaceous this strike slip faulting was related to north northwestward oblique subduction of the proto pacific izanagi kula or pacific plate under the eastern margin of the eurasian plate

radarsat 2 d insar for ground displacement in permafrost terrain validation from iqaluit airport baffin island canada abstract the use of differential interferometric synthetic aperture radar d insar is rapidly gaining acceptance as a source of ground displacement information for permafrost regions the accuracy of the information however is still not well established this paper uses a stack of radarsat 2 d insar data to map seasonal ground displacement at the iqaluit airport baffin island canada the accuracy and information content of the d insar products are evaluated with a variety of ground truth data the d insar derived seasonal ground displacement patterns align well with surficial geology units and reflect the thaw settlement characteristics of the sediments they also identify localised displacement patterns in the vicinity of features such as ice wedges and frost cracks comparisons with ground settlement measurements from in situ thaw tubes indicate sub centimetre agreement in dry areas in low lying wet areas however subject to saturation and flooding the d insar stack significantly underestimates the true settlement detecting only 3 7 cm of the 8 5 cm thaw tube measurement the combination of high phase gradients and poor coherence over intermittently flooded surfaces makes it challenging to preserve reliable phase measurements in these areas information from electromagnetic surveys shows that some surface displacement is related to sub surface conditions