was the black sea catastrophically flooded in the early holocene abstract a catastrophic flooding of the black sea basin was proposed to have occurred during its reconnection to the ocean in the early holocene possible cultural consequences of the flood include the migration of neolithic farmers from around the black sea towards central europe as well as the creation of flood myths stratigraphic and paleo geomorphologic information from danube delta aided by radiocarbon ages on articulated mollusks constrain the level in the black sea before the marine reconnection to ca 30 m below the present sea level rather than 80 m or lower if the flood occurred at all the sea level increase and the flooded area during the reconnection were significantly smaller than previously proposed

dynamic triggering stress modeling and a case study 1 changes in the static stress can trigger nearby earthquakes that occur within a few fault lengths from the causative event transient stresses caused by passage of surface waves commonly trigger events at remote distances yet little is documented or understood about the processes and stresses necessary for remote triggering to understand the causative stresses and environments behind remote or dynamic triggering we must decipher the stresses caused by the passage of the surface waves in relation to the local stress field and fault conditions where the triggered events occur in this study we model the change in the stress field that the passing of rayleigh and love waves causes on a fault plane of arbitrary orientation relative to the direction of propagation of the waves and we apply a coulomb failure criterion to calculate the potential of these stress changes to trigger reverse normal or strike slip failure we compare these model results with data from dynamically triggered earthquakes in the australian bowen basin an area with low seismicity and mapped regional stress and that is at the margin of a stable continental craton our data analysis shows that for this region surface waves arriving at 45 from the average strike direction are the most likely to trigger local seismicity this agrees with our observations

exploration of remote triggering a survey of multiple fault structures in haiti triggering studies provide an important tool for understanding the fundamental physics of how faults slip and interact and they also provide clues about the stress states of faults in this study we explore how seismic waves from the 27 february 2010 mw8 8 maule chile mainshock interact with the left lateral strike slip enriquillo plantain garden fault epgf and surrounding reverse faults in the southern haiti peninsula the chile mainshock occurred 6 000 km away and just 46 days after the 12 january 2010 mw7 0 haiti earthquake a tragic event which activated multiple faults in the southern haiti peninsula during the surface waves of the chile mainshock several tectonic tremor signals were observed originating from south of the epgf trace cross correlation of the triggered tremor and transient stresses resolved onto to the epgf indicates that the love wave of the chile mainshock was the primary driving mechanism of the triggered deep shear slip and tremor signals as opposed to dilatational stress changes generated by the rayleigh wave we also searched for any influence of transient stresses on haiti aftershock activity by applying the matched filter technique to multiple days of seismic data around the time of the chile mainshock while we identified a slight increase in haiti aftershock activity rate the rate changes were significant only when small magnitude events were included in the significance tests these observations are generally consistent with recent inferences that deep tectonic tremor is more sensitive than shallow earthquakes to external stress perturbations

discontinuity surfaces clinoforms and facies architecture in a wave dominated shoreface shelf parasequence abstract detailed outcrop analysis of a wave dominated shoreface shelf parasequence exposed in the book cliffs utah reveals minor stratigraphic discontinuities which define clinoforms two types of discontinuity are recognized each with a distinctive lithologic character and geometry nondepositional discontinuities are marked by an abrupt decrease in the thickness and amalgamation of storm generated event beds and are interpreted to record hiatuses in sedimentation these discontinuities define clinoforms with a concave upward geometry that dip gently 0 02 0 58 over distances of 800 6000 m down depositional dip erosional discontinuities are marked by an abrupt increase in event bed amalgamation grain size and sand content and are interpreted as enhanced storm wave scours these discontinuities define more steeply dipping 0 22 0 95 concave upward clinoforms that extend over 100 1600 m down depositional dip and 500 1500 m along depositional strike the distribution and amalgamation of minor stratigraphic discontinuities defines linear zones of distinctive facies architecture that are oriented parallel to the paleoshoreline trend using the simple assumption that the shoreface shelf equilibrium profile remained approximately constant for each type of discontinuity throughout shoreface migration the bruun rule intra parasequence facies architecture can be speculatively interpreted in terms of shoreline trajectory which reflects the balance between sediment supply and accommodation the resulting interpretations support the notion that shoreline trajectory exerts a strong control on intra parasequence facies architecture and preservation of the shoreface shelf profile

accommodation and sediment supply controls on clastic parasequences a meta analysis this study combines data from many published case studies to undertake a quantitative characterization of clastic parasequences with the aim to determine how accommodation sediment supply and autogenic sediment storage dynamics are recorded in their sedimentary architecture and stacking patterns results of this study are used to critically evaluate the validity of paradigms and models that are routinely used to explain and predict trends in the anatomy and arrangement of parasequences data on 957 parasequences from 62 case studies of clastic shallow water successions were coded in a relational database which includes outcrop and subsurface datasets of ancient and quaternary examples these units cover the preserved records of both river dominated deltas and wave dominated coasts representing shoreline transits over a breadth of timescales likely of both local and regional extent the role of extant accommodation rates of creation of accommodation and rates of sediment supply in determining parasequence architecture is assessed through analysis of relationships between i proxies of these variables at different scales rates of aggradation and progradation facies belt shoreline trajectories systems tract type parasequence set stacking patterns parasequence progradation angle and stratigraphic rise size of feeder rivers and ii parameters that describe the geometry and stacking style of parasequences and associated shallow water sand bodies statistical analyses of database outputs indicate which proxies of accommodation sediment supply and accommodation sediment supply ratio are significant as predictors of parasequence architecture and allow for interpretations of the importance of allogenic and autogenic factors the principal results of this study reveal the following i parasequence thickness varies as a function of water depth accommodation generation and erosional truncation and these variations are also reflected across types of systems tracts and parasequence sets ii the dip length of parasequence sand bodies demonstrates scaling with measures of accommodation sediment supply ratio at multiple scales partly in relation to the possible effect of sediment supply on progradation rates iii in systems tracts stratigraphic trends in parasequence stacking due to autogenic mechanisms or to acceleration or deceleration in relative sea level fluctuations are not revealed quantitatively iv some association is seen between the abundance of deltaic or river dominated parasequences and progradational stacking v positive but modest correlation is observed between measures of river system size and the dip length of shallow marine parasequence sand bodies the resulting insights can be applied to guide sequence stratigraphic interpretations of the rock record and the characterization of sub seismic stratigraphic architectures of subsurface successions

more than ten years of lusi a review of facts coincidences and past and future studies abstract the lusi mud eruption in east java indonesia has continued unabated for more than ten years with no end in sight this review summarizes what has been learned about this intriguing system from its inception to the current 2017 well established metastable geysering system that continuously erupts mud breccia gas steam and water we discuss the initiation of lusi highlighting discrepancies and evidence through the published data to build a comprehensive database that emphasizes how the results converge towards a natural scenario of this system we argue that attempts to understand constrain or predict the behaviour of this system that rely on a drilling trigger can not explain subsequent observations on the other hand we show that a well constrained conceptual model recognizing lusi as a volcanically linked hydrothermal system has provided important insights for the documented observations over the last eleven years the response of lusi to the yogykarta earthquake falls directly within the range of earthquake triggering phenomena globally of similar hydrothermal geothermal systems suggesting a natural trigger as the more likely culprit for the lusi phenomenon we also offer some future directions of additional scrutiny for understanding this newborn tectonic scale volcanic hydrothermal complex

shoreline autoretreat substantiated in flume experiments abstract under conditions of constant sediment supply s to the basin and a steady rate of rise a in relative sea level the autoretreat theory predicts that shorelines can retreat landwards at a relatively early stage of delta growth and attain an autobreak state after which the existing subaqueous slope begins to be starved of sediment and thereby lose its clear delta front configuration a numerical model based on this theory further suggests that shoreline migration depends on the inclination of basin s basement slope and subaqueous depositional slope and to a lesser degree on the inclination of subaerial depositional slope two dimensional flume experiments in which a miniature delta is subject to steady forcing a const 0 s const 0 were conducted to test the expectations of the autoretreat theory the experiments consisted of two different series of runs one was of modulation associated with a narrow range of the ratio of water discharge to sediment discharge q s the other was of q s modulation with kept nearly constant the q s ratio was mostly responsible for changes in but also affected to some extent all experimental runs substantiated the landward turnaround feature of shoreline accretion i e autoretreat and the geometrical break of the delta front shape during its retreat phase i e autobreak the obtained shoreline trajectories hold their geometrical patterns even after they were nondimensionalized in terms of the s a ratio a key hypothesis confirmed in the experiments is that a and s can never balance each other both of the experimental series brought some systematic change of shoreline trajectories but the variations of shoreline trajectory due to modulation were much more striking than those related to q s even these contrasting results are consistent with the numerical predictions the present experimental results support the applicability of the autoretreat concept to natural environments and help clarify the processes governing the regression and transgression of a shoreline on a constructional margin

calcite and aragonite precipitation from seawater solutions of various salinities precipitation rates and overgrowth compositions abstract the reaction rate and composition of calcite and aragonite overgrowths precipitated from seawater solutions of various salinities i e s 5 15 25 35 44 were determined at 25 c and 10 2 5 atm co2 partial pressure using a constant disequilibrium seeded technique the rate data were fitted to an empirical rate law of the form log r n c or a 1 log k where n is the empirical reaction order and k is the rate constant calcite precipitation rates in seawater solutions do not vary appreciably as a result of salinity variations over the range investigated while those for aragonite show an increase in going from the higher i e s 35 44 to the lower i e s 5 15 25 salinity range this study also confirms previously published findings that above a given saturation state i e c 2 6 aragonite precipitates more rapidly than calcite at 25 c the incorporation of sr2 in aragonite and mg2 in calcite overgrowths are independent of the precipitation rate the partition coefficient of sr2 in aragonite is approximately equal to unity and is unaffected by salinity variations between 5 and 44 however the mg2 partition coefficient in calcite increases with decreasing salinity of the parent seawater solutions possibly as a result of variations in the sulfate content of the solutions and solids the experimental results were discussed in the context of a number of geological environments

parasequence types in shelfal mudstone strata quantitative observations of lithofacies and stacking patterns and conceptual link to modern depositional regimes mudstone strata have a vast variety of physical biogenic and chemical attributes at the lamina to bed scale approximately millimeters to decimeters thick our observations of more than 7 km of paleozoic to cenozoic mudstones revealed ordered patterns in this variety i e recurrent associations of lithofacies bedding style sedimentary structures and stratal architecture at bedset to parasequence scales approximately decimeters to meters thick we quantified characteristics of each association and their stacking patterns in vertical succession and linked them to sets of depositional processes most shelf mudstone strata appear to have accumulated in one of three facies association successions fass that can be related to depositional regimes through characteristic modes of sediment transport and accumulation as well as variations in benthic energy and oxygen levels we interpret these three fass as records of mud accumulation on different portions of continental shelves that were dominated by storm waves river floods or tidal currents each fas records a distinct parasequence type this approach can help fully integrate insights from oceanographic studies into more robust interpretations of the rock record and rock property maps

crustal velocity model along the southern cuban margin implications for the tectonic regime at an active plate boundary summary a new 1 d velocity model along the southern cuban margin has been determined using local earthquake data which are the result of the merged cuban and jamaican catalogues simultaneous inversion using joint hypocentre determination was applied to solve the coupled hypocentre velocity model problem we obtained a seven layer model with an average moho interface at 20 km the average velocity was found to be 7 6 km s 1 on the top of the crust mantle transition zone and 6 9 km s 1 in the basaltic layer of the crust the improvement in the earthquake locations allowed us for the first time to use local seismicity to characterize the activity on local faults and the stress regime in the area for this purpose 34 earthquake focal mechanisms were determined along the eastern segments of the oriente fault these solutions are consistent with the known left lateral strike slip motion along this major structure as well as with the stress regime of two local structures 1 the cabo cruz basin and 2 the santiago deformed belt the first structure is dominated by normal faults with minor strikeslip components and the second by reverse faults the shallow seismicity in the cabo cruz basin is associated with fault planes trending n55 58 e and dipping 38 45 to the north the santiago deformed belt on the other hand exhibits diverse fault plane orientations these local structures account for most of the earthquake activity along the southern cuban margin deep seismicity observed in the santiago deformed belt supported by focal mechanisms suggests underthrusting of the gonave microplate beneath the cuban block in this area the principal stress orientations obtained from stress inversion of earthquake focal mechanisms suggest a thrust faulting regime along the southern cuban margin we obtained a nearly horizontal 1 and nearly vertical 3 which indicates active compressional deformation along the major oriente transcurrent fault in agreement with the dominant structural trend associated with the santiago deformed belt

principles of regression and transgression the nature of the interplay between accommodation and sediment supply the rate of change of accommodation at the shoreline a and the rate of sediment supply s are the primary factors controlling regression and transgression in the geological record or retreat and advance of a coastal depositional system the generally accepted notion here referred to as the a s ratio concept stating that the migration of a shoreline is controlled principally by the magnitude of the ratio of a to s is insufficient and somewhat misleading partly owing to the problem of dimensional confusion the interplay of a and s inevitably results in autoretreat of the shoreline whereby the seaward advance of any shoreline is halted and is subsequently turned to landward retreat provided there is a continuous rise of relative sea level how effective the autoretreat process is depends for a given period of relative sea level rising upon the length of potential time period for the seaward advance of shoreline and is proportional to a 2 s and a super 1 5 s super 0 5 in two and three dimensional sediment dispersal modes respectively autoretreat becomes more effective as a increases and or s decreases a functions more critically to the effectiveness than s does the a s ratio concept is only approximately applicable when autoretreat is less effective i e with very low a and or very high s in this sense the autoretreat theory and the a s ratio concept are complementary to each other the autoretreat mechanism is expected to be substantially useful not only in fluvial deltas but also in many other depositional systems e g barrier islands whose evolution has been considered in terms of the a s ratio concept

triggered creep as a possible mechanism for delayed dynamic triggering of tremor and earthquakes the passage of radiating seismic waves generates transient stresses in the earth s crust that can trigger slip on faults far away from the original earthquake source the triggered fault slip is detectable in the form of earthquakes 1 3 and seismic tremor 4 7 however the significance of these triggered events remains controversial 8 9 in part because they often occur with some delay long after the triggering stress has passed here we scrutinize the location and timing of tremor on the san andreas fault between 2001 and 2010 in relation to distant earthquakes we observe tremor on the san andreas fault that is initiated by passing seismic waves yet migrates along the fault at a much slower velocity than the radiating seismic waves we suggest that the migrating tremor records triggered slow slip of the san andreas fault as a propagating creep event we find that the triggered tremor and fault creep can be initiated by distant earthquakes as small as magnitude 5 4 and can persist for several days after the seismic waves have passed our observations of prolonged tremor activity provide a clear example of the delayed dynamic triggering of seismic events fault creep has been shown to trigger earthquakes 10 12 and we therefore suggest that the dynamic

dynamic triggering of microearthquakes in three geothermal volcanic regions of california geothermal volcanic regions are most susceptible to local earthquake triggering by regional and remote earthquakes transient stresses caused by surface waves of these earthquakes can activate critically stressed faults though earthquakes can be triggered in geothermal volcanic regions it is less understood how these regions differ in their triggering responses to distant earthquakes we conduct a systematic survey of local earthquakes triggered by distant earthquakes in three geothermal volcanic regions of california long valley caldera coso geothermal field and geysers geothermal field we examine waveforms of distant earthquakes with magnitudes 5 5 occurring between 2000 and 2012 and compute statistics to confirm the significance of our findings we find that long valley coso and geysers vary in triggering frequency 2 0 3 8 and 6 8 in the 12 year period respectively and when compared to the triggering of deep tectonic tremors along the parkfield cholame section of san andreas fault 9 2 in the 12 year period stress triggering thresholds vary among the regions with long valley having the highest of 5 kpa and 1 kpa for the other regions because dynamic stresses from distant earthquakes are similar in these three regions the varying triggering behavior likely reflects faults having a tendency to be at or near failure this is compatible with geysers having a higher a value in the gutenberg richter relationship and higher geothermal productivity than the other two regions the observation of more frequent triggering of tremor than microearthquakes is consistent with recent laboratory studies on increasing triggerability with lower effective stress

comparisons of triggered tremor in california abstract we conduct a visual inspection of deep nonvolcanic tremor triggered by large teleseismic earthquakes around the calaveras fault in northern california nc and the san jacinto fault in southern california sc out of the 42 large m w 7 5 earthquakes between 2001 and 2010 only the 2002 m w 7 9 denali fault earthquake triggered clear tremor in these two regions this is in marked contrast with the parkfield cholame section of the san andreas fault in central california cc where 12 earthquakes have triggered tremor in that region the amplitude of the triggered tremor correlates with that of the triggering surface waves in cc and is consistent with the clock advance model the lack of widespread triggered tremor in nc and sc is not simply a consequence of their different background noise levels from cc but rather reflects different background tremor rates in these regions online material tables of parameters for triggered nontriggered teleseismic earthquakes and triggered tremors and figures of band pass filtered seismograms maximum vertical pgvs versus median amplitude of band pass filtered envelope functions tremor amplitude versus pgv and s wave spectra and corresponding noise of local selected earthquakes

slow earthquakes and nonvolcanic tremor nonvolcanic tremor is observed in close association with geodetically observed slow slip events in subduction zones accumulating evidence points to these events as members of a family of slow earthquakes that occur as shear slip on the downdip extensions of fault zones in a regime that is transitional between a frictionally locked region above and a freely slipping region below by virtue of their locations and their properties slow earthquakes are certain to provide new insights into the behavior of earthquakes and faulting and into the hazard they embody

tectonic tremor and deep slow slip on the alpine fault 1 tectonic tremor is characterized by persistent low frequency seismic energy seen at major plate boundaries although predominantly associated with subduction zones tremor also occurs along the deep extension of the strike slip san andreas fault here we present the first observations of tectonic tremor along new zealand s alpine fault a major transform boundary that is late in its earthquake cycle we report tectonic tremor that occurred on the central section of the alpine fault on 12 days between march 2009 and october 2011 tremor hypocenters concentrate in the lower crust at the downdip projection of the alpine fault coincide with a zone of high p wave attenuation low qp and bright seismic reflections occur in the 25 45 km depth range below the seismogenic zone and may define the deep plate boundary structure extending through the lower crust and into the upper mantle we infer this tremor to represent slow slip on the deep extent of the alpine fault in a fluid rich region marked by high attenuation and reflectivity these observations provide the first indication of present day displacement on the lower crustal portion of the australia pacific transform plate boundary

contributions to sequence stratigraphy from analogue and numerical experiments the sequence stratigraphic model although no longer focused on eustasy and accommodation has been until recently based largely on observation and interpretation of outcrop and subsurface data this approach may be restrictive if the current model places limits on what is observed and how observations are interpreted to make progress in our understanding of strata the sequence stratigraphic model and method should be tested against and fully incorporate theoretical and experimental results that provide new knowledge of 1 autogenesis 2 intrinsic stratigraphic responses 3 alluvial grade and 4 scales appropriate to single depositional systems evolving with relative sea level changes more extensive inclusion of analogue and numerical experimental results could lead to significant modification and refinement of existing sequence stratigraphic models

the shallow marine architecture knowledge store a database for the characterization of shallow marine and paralic depositional systems abstract the shallow marine architecture knowledge store smaks is a relational database devised for the storage of hard and soft data on the sedimentary architecture of ancient shallow marine and paralic siliciclastic successions and on the geomorphological organization of corresponding modern environments the database allows incorporation of data from the published literature which are uploaded to a common standard to ensure consistency in data definition the database incorporates data on geological entities of varied nature and scale i e surfaces depositional tracts architectural elements sequence stratigraphic units facies units geomorphic elements including attributes that characterize their type geometry spatial relations hierarchical relations and temporal significance furthermore geological entities are assigned to depositional systems or to parts thereof that can be classified on multiple parameters e g shelf width delta catchment area tied to metadata e g data types data sources the smaks permits the quantitative characterization of modern and ancient shallow marine and paralic clastic depositional systems it aims to serve as a repository of analogue information for hydrocarbon bearing successions and as a research tool that can be applied to aid the development of facies models or to assess the sensitivity of depositional systems to particular controlling factors for example to demonstrate the wide applicability of the database in fields of both fundamental and applied research example database output is presented that i includes data from wave tide and fluvial dominated shallow seas and sedimentary successions and ii covers a wide depositional spectrum from backshore to shelf edge settings the examples include information on the facies organization of different types of paralic sub environments on the hierarchical arrangement of architectural elements that form deltaic constructional units in quaternary deltas on the morphometry of modern and quaternary tidal sand ridges and on the geometry of parasequence scale nearshore sandstone belts from the upper cretaceous of the western interior seaway in utah usa

stratigraphic uncertainty in sparse versus rich data sets in a fluvial deltaic outcrop analog ferron notom delta in the henry mountains region southern utah the turonian notom delta is one of the ferron fluvial deltaic wedges deposited in the cretaceous foreland basin of north america and is well exposed in the henry mountains region utah this article uses variable sampling of measured sections of the fluvial deltaic wedge along a 19 mi 30 km outcrop belt to address correlation uncertainties in sparse data sets such as are common in subsurface studies a high resolution sequence stratigraphic analysis based on 58 measured sections extensive walking out of beds and field photomosaics shows that the wedge is composed of 43 parasequences 18 parasequence sets and six depositional sequences resampling the outcrop belt with 13 sections provides a sparse data set correlations using the data set show considerable uncertainties fluvial complexity is greatly underestimated and in the extreme case only 40 of the fluvial bodies are identified overcorrelation results in as much as 400 exaggeration of sandstone width and thickness some of the uncertainties can be reduced by incorporating nonmarine sequence stratigraphic models and various techniques that allow a more reasonable evaluation of fluvial body geometry with sparse data uncertainties also arise in marine successions a key challenge is to identify and correlate the small scale units particularly forced regressive deposits many of their diagnostic features that can be easily recognized from outcrops and cores may not be as easily detected from well logs and on seismic data in subsurface studies where sparse data are observed integrating detailed facies analysis cores and sequence stratigraphic concepts is critical to predict the occurrence and understand the architecture of such deposits

palaeogeography and evolution of the godavari delta east coast of india during the holocene an example of wave dominated and fan delta settings abstract we investigated the holocene evolution of the godavari delta along the east coast of india by analyses of landforms and 11 borehole cores collected from the delta plain during 2010 2013 with 113 14c dates the godavari delta covering an area of 5820 km2 is one of the world s largest wave dominated deltas fringed by a 30 km wide beach ridge plain our analysis of sediment facies and their ages indicated that the holocene marine sequence thickens seaward from 10 m to more than 50 m and that the local relative sea level rapidly rose from 43 5 m to 7 5 m below the present sea level during 10 9 8 0 cal ky bp followed by a slow rise up to its current level around 5 cal ky bp spatio temporal variations in sediment accumulation rates and palaeo shorelines for the last 6 ky revealed successive changes of the main depocentre delta lobe we recognised six stages of delta evolution with distinct cyclic shifts of delta lobes controlled by avulsions a linear beach ridge located 12 14 km inland from the present shoreline which separates the first three lobes from the last three represents the effect of coastal erosion of past cuspate delta lobes as does the current linear shoreline of the central part of the delta our study documents continuous net progradation during the holocene on millennial to centennial time scales however a considerable decrease of sediment discharge due to dam construction and water diversion since the 1970s has exacerbated coastal erosion resulting in shrinking of the godavari delta plain and tipping it into a persistent destruction phase

statistical properties of low frequency earthquakes triggered by large earthquakes in southern taiwan abstract the recent discovery of triggered tremors tts and low frequency earthquakes lfes in various tectonic environments provides an opportunity for studying the fundamental properties and physical mechanisms of deep tectonic tremor here we quantify the relationship between tts and lfes beneath the central range in southern taiwan and their statistical properties during the teleseismic waves of six large distant earthquakes using waveforms of 11 lfes triggered by the 2005 m w 8 6 nias earthquake as templates we scan through 12 hours of waveform data around six mainshocks and identify a total of 783 lfes the lfes were mainly located in a compact region between 12 and 36 km in depth near the chaochou lishan fault most of lfes occurred within tt during the passage of large amplitude surface waves and the increase of the lfe rate during the surface waves is statistically significant the lfe rates do not follow an omori s type decay but rather abruptly return to the background rate immediately after the surface wave passage these findings suggest that lfes do not trigger any additional lfes at later times and are primarily driven by an external forcing our observations are consistent with the inference that tts consist of many reoccurring lfes

distribution of discontinuous mudstone beds within wave dominated shallow marine deposits star point sandstone and blackhawk formation eastern utah deposits of wave dominated shorelines are typically considered to act as relatively simple hydrocarbon reservoirs and are commonly modeled as tanks of sand however important heterogeneities that can act as barriers to fluid flow occur at the parasequence bedset and bed scales especially in viscous oil or low permeability oil fields heterogeneities at the parasequence and bedset scales have been well studied but discontinuous mudstone beds occurring within the shoreface have received little attention the book cliffs and wasatch plateau are among the best exposed and best studied deposits of wave dominated shallow marine systems in the world two parasequences within these outcrops have been studied in detail to investigate the distributions of intrashoreface shales and to propose models for the controls on their distribution a data set consisting of 30 km 18 6 mi of virtual outcrops derived from oblique helicopter mounted light detection and ranging lidar scanning with supporting stratigraphic sections makes it possible to collect a large quantity of accurate geometric data of depositional elements from inaccessible cliffs nine hundred and twenty one discontinuous mudstone beds were measured these occur as ellipses with long axes oriented normal to the paleoshoreline lengths and widths of these mudstone beds exhibit a lognormal distribution with means of 21 9 and 13 8 m 71 9 and 45 3 ft respectively within the shoreface succession the number of mudstone beds increases downward whereas size does not vary significantly with stratigraphic height an average of 100 m 328 ft cumulative length of shale exists per 100 m 328 ft of horizontal outcrop this increases threefold near both wave dominated deltas and bedset boundaries that reflect minor sea level fluctuations during progradation

surface wave potential for triggering tectonic nonvolcanic tremor corrected abstract source processes commonly posed to explain instances of remote dynamic triggering of tectonic nonvolcanic tremor by surface waves include frictional failure and various modes of fluid activation the relative potential for love and rayleigh wave dynamic stresses to trigger tectonic tremor through failure on critically stressed thrust and vertical strike slip faults under the coulomb griffith failure criteria as a function of incidence angle are anticorrelated over the 15 to 30 km depth range that hosts tectonic tremor love wave potential is high for strike parallel incidence on low angle reverse faults and null for strike normal incidence the opposite holds for rayleigh waves love wave potential is high for both strike parallel and strike normal incidence on vertical strike slip faults and minimal for 45 incidence angles the opposite holds for rayleigh waves this pattern is consistent with documented instances of tremor triggered by love waves incident on the cascadia megathrust and the san andreas fault saf in central california resulting from shear failure on weak faults apparent friction is 0 2 documented instances of tremor triggered by surface waves with strike parallel incidence along the nankai megathrust beneath shikoku japan however are associated primarily with rayleigh waves this is consistent with the tremor bursts resulting from mixed mode failure crack opening and shear failure facilitated by near lithostatic ambient pore pressure low differential stress with a moderate friction coefficient 0 6 on the nankai subduction interface rayleigh wave dilatational stress is relatively weak at tectonic tremor source depths and seems unlikely to contribute significantly to the triggering process except perhaps for an indirect role on the saf in sustaining tremor into the rayleigh wave coda that was initially triggered by love waves

sedimentologic and sequence stratigraphic characteristics of wave dominated deltas wave dominated deltaic strata form prolific hydrocarbon plays in many mature basins across the world examples include the jurassic brent group play in the north sea offshore united kingdom and norway e g husmo et al 2003 eocene jackson group and oligocene frio formation plays texas onshore united states e g fisher et al 1970 galloway and morton 1989 and tertiary plays in the niger delta province offshore nigeria e g evamy et al 1978 the baram delta province offshore brunei e g rijks 1981 and the columbus basin offshore trinidad and tobago e g sydow et al 2003 wave dominated deltas also form key exploration targets in frontier basins e g triassic snadd formation barents sea offshore norway klausen et al 2014 2016 the overall architecture of many wave dominated deltaic reservoirs is determined by their sequence stratigraphic framework together with their structural configuration sequence stratigraphic frameworks contain elements such as shoreface shelf parasequences bounded by flooding surfaces and fluvio estuarine complexes that fill incised coastal valleys developed at sequence boundaries the internal facies distributions and stacking patterns of such elements are ordered which aids prediction of reservoir character and behavior outcrop analogs of wave dominated deltaic reservoirs display aspects of ordered stratigraphic architecture across a range of spatial scales that are equivalent to those observed in core well log and seismic data and can therefore be used to support interpretation of their subsurface counterparts the cretaceous blackhawk formation contains wave dominated deltaic strata that are superbly exposed in the book cliffs of eastcentral utah figure 1a the extensive continuous exposures of the book cliffs outcrop belt have allowed the wave dominated deltas and related deposits to be mapped for tens of kilometers e g young 1955 balsley 1980 and consequently these strata were the birthplace of high resolution sequence stratigraphy using outcrop data van wagoner et al 1990 the blackhawk formation and related

remotely triggered nonvolcanic tremor in sumbawa indonesia we present for the first time evidence for triggered tremor beneath the island of sumbawa indonesia we show triggered tremor in response to three teleseismic earthquakes the mw9 0 2011 tohoku earthquake and two oceanic strike slip earthquakes mw 8 6 and mw8 2 offshore of sumatra in 2012 we constrain an apparent triggering threshold of 1 mm s ground velocity that corresponds to about 8 kpa dynamic stress peak tremor amplitudes of about 180 nm s are observed and scale with the ground velocity induced by the remote earthquakes triggered tremor responds to 45 65 s period surface waves and predominantly correlates with rayleigh waves even though the 2012 oceanic events have stronger love wave amplitudes we could not locate the tremor because of minimal station coverage but data indicate several potential source volumes including the flores thrust the java subduction zone or tambora volcano

carbonate cementation in a sequence stratigraphic framework upper cretaceous sandstones book cliffs utah colorado abstract three macroscopic diagenetic features can be recognized in the sandstones of the upper cretaceous desert member of the blackhawk formation and castlegate sandstone of the mesaverde group exposed in the book cliffs utah each of which have distinctive form geometry and stratigraphic distribution diagenetic alterations are 1 leached zones whitecaps up to 10 m thick beneath coal beds 2 large up to 8 m concretionary carbonate cemented bodies in amalgamated shoreface and thin fluvial sandstones and 3 thin up to 2 m laterally extensive carbonate cemented horizons beneath major marine flooding surfaces each feature has distinct petrographic and geochemical signatures and formed through discrete diagenetic processes large isolated carbonate cemented bodies are composed of ferroan dolomite most of which precipitated during early diagenesis field and petrographic data coupled with stable isotope data early cements 13c 2 5 to 3 4o oo vpdb 18o 7 8 to 12 0o oo vpdb 87sr 86sr 0 7078 later cements 13c 3 1 to 5 7o oo vpdb 18o 12 0 to 15 1o oo vpdb 87sr 86sr 0 7093 suggest precipitation from meteoric fluids input into sediments during times of relative sea level fall the source of carbonate for the dolomite cement was dissolution of detrital dolomite from beneath coals by organic acids and subsequent mobilization by meteoric fluids carbonate precipitation in laterally extensive cement horizons appears to have started as a result of hiatus in sediment accumulation during marine flooding events relative sea level rise cement precipitation in these horizons continued through sediment burial as a result of organic matter oxidation reactions in overlying organic rich mudstones the results of this study show a link between sedimentation related to changes in relative sea level and diagenesis leading to the potential for the development of process based predictive models of early diagenesis in depositional successions

high resolution deep tectonic tremor locations beneath the san andreas fault near cholame california using the double pair double difference location method we determine high precision deep tectonic tremor locations beneath the san andreas fault saf near cholame california region using a newly developed double pair double difference location method and a new 3 d vs model compared to the previous results newly determined tremor locations are more consistent with known low frequency earthquake lfe locations and are more concentrated along the saf new tremor locations near cholame show clear contrast in the predominant depth of the tremor activity across the saf and also show contrasts in the degree of periodic behavior both along and across the saf they collectively define a very special tremor generation region vstr near the intersection corner between the saf and the adjacent san juan fault sjf in the vstr new locations reveal some isolated tremor clusters which may occur on multiple deep fault patches for these isolated clusters some are closer to the saf and some are closer to the sjf implying that both the saf and sjf may extend to the ductile lower crust possible interaction between the saf and sjf in the lower crust beneath the vstr combined with the trapped high pressure fluids may explain the strong tremor activity the isolated tremor clusters and the characteristic tremor occurrence patterns and depth distributions in this region

oxygen isotope fractionation in marine aragonite of coralline sponges oxygen isotope values of the extant caribbean coralline sponge ceratoporella nicholsoni are compared with published temperatures and 18o of water calculated from salinities the measured values from aragonitic sponge skeletons have a mean offset of 1 0 0 1 from calculated calcite equilibrium values aragonite calcite 1 0010 this is in good agreement with published values from synthetic aragonite they further agree with published near equilibrium oxygen isotope values of temperate and cold water molluscs and foraminifera extrapolated to the temperature range of the coralline sponges these results and the mode of skeleton formation of ceratoporella nicholsoni suggest that these sponges precipitate aragonite close to isotopic equilibrium the temperature dependence of oxygen isotopic fractionation between the aragonite of ceratoporella nicholsoni and water is only roughly constrained by the available data due to the narrow temperature range of the caribbean reef sites however as the data suggest oxygen isotopic equilibrium we can calculate a well constrained temperature equation combining temperate and cold water equilibrium values from molluscs and foraminifera with our sponge data full size image 1 k and full size image 1 k

remote triggering of non volcanic tremor around taiwan summary we perform a systematic survey of triggered deep non volcanic tremor beneath the central range cr in taiwan for 45 teleseismic earthquakes from 1998 to 2009 with mw 7 5 and epicentral distance 1000 km to the broad band station tpub triggered tremors are visually identified as bursts of high frequency 2 8 hz non impulsive and long duration seismic energy that are coherent among many seismic stations and modulated by the teleseismic surface waves out of the 45 earthquakes we identified nine teleseismic events associated with nine tremor sources in the southern and five in the northern cr most of the tremor sources are located within the depth range of 15 25 km in the lower crust above the moho we find that the amplitudes of the surface waves play an important role in determining the triggering potential and the apparent triggering threshold is 0 1 cm s 1 or 7 8 kpa however such threshold is partially controlled by the background noise level which could prevent weaker tremor triggered by surface waves with smaller amplitudes from being identified the amplitudes of the triggered tremor show a positive correlation with the amplitudes of the triggering surface waves consistent with the predictions by the clock advance model in addition to amplitudes other factors such as frequency contents and incidence angles also affect the triggering potential we find that intermediate period 30 10 s surface waves could trigger modulate tremors suggesting that long period 30 s surface waves are not always required in long range triggering tremors appear to be triggered by both love and rayleigh waves when the incidence angles are parallel to the strike of the cr all six events triggered tremor primarily during the rayleigh waves for strike normal incidence only the 2001 mw7 8 kunlun earthquake showed predominant love wave triggering this observation can be qualitatively explained by a simple coulomb failure for a left lateral shear on the low angle detachment fault beneath the southern cr

high resolution sequence stratigraphic correlation between shallow marine and terrestrial strata examples from the sunnyside member of the cretaceous blackhawk formation book cliffs eastern utah the sunnyside member of the upper cretaceous blackhawk formation in the book cliffs of eastern utah provides an ideal opportunity to investigate high resolution sequence stratigraphic correlation between shallow marine and terrestrial strata in an area of outstanding outcrop exposure the thick laterally extensive coal seam that caps the sunnyside member is critical for correlating between its shallow marine and terrestrial components petrographic analysis of 281 samples obtained from 7 vertical sections spanning more than 30 km 18 mi of depositional dip enabled us to recognize a series of transgressive regressive coal facies trends in the seam on this basis we were able to identify a high resolution record of accommodation change throughout the deposition of the coal as well as a series of key sequence stratigraphic surfaces the stratigraphic relationships between the coal and the siliciclastic components of the sunnyside member enable us to correlate this record with that identified in the time equivalent shallow marine strata and to demonstrate that the coal spans the formation of two marine parasequences and two high frequency fourth order sequence boundaries this study has important implications for improving the understanding of sequence stratigraphic expression in terrestrial strata and for correlating between marine and terrestrial records of base level change it may also have implications for improving the predictability of vertical and lateral variations in coal composition for mining and coalbed methane projects

quantitative sequence stratigraphy sequence stratigraphy based on wire line logs cores and outcrops is entering its fourth decade of mainstream usage in industry and academia the technique has proved to be an invaluable tool for improving stratigraphic analyses in both clastic and carbonate settings here we present a simple quantitative technique to support sequence stratigraphic interpretations in clastic shallow marine systems the technique uses two pieces of data that are readily available from every subsurface field or outcrop study 1 parasequence thickness t and 2 parasequence sandstone fraction sf the key assumptions are that parasequence thickness can be used as a proxy for accommodation at the time of deposition and parasequence sandstone fraction can be used as a proxy for sediment supply this means that quantitative proxies for rates of accommodation development and sediment supply can be acquired from wire line logs cores and outcrop data vertical trends in parasequence thickness divided by sandstone fraction t sf approximate trends expected in systems tracts for changes in ratios of rate of accommodation development to rate of sediment supply the technique termed tsf analysis can also be applied at lower order sequence and composite sequence scales it provides a quantitative and objective methodology for determining rank and order of sequence stratigraphic surfaces and units absolute t sf values can be used to determine shoreline stacked shoreline and shelf margin trajectories four case studies are presented which demonstrate the robustness of the technique across a range of different data sets implications and potential future applications of tsf analyses are discussed

antarctic icequakes triggered by the 2010 maule earthquake in chile large earthquakes can trigger seismicity in remote regions analysis of seismic data from antarctica reveals ice quakes coincident with passing seismic waves from the 2010 chile earthquake suggesting that the ice sheet is sensitive to such triggers

parameterizing parasequences importance of shelf gradient shoreline trajectory sediment supply and autoretreat the basic reservoir flow unit in shallow marine depositional systems is the parasequence since it is bounded top and base by regionally extensive shales that can form barriers to fluid flow as a result it is the key stratigraphic unit requiring parameterization for both exploration and development purposes a database comprising 3385 measurement points from 385 parasequences from 28 locations and 16 different passive margin and foreland basins was compiled from outcrop and subsurface data analysis of the data suggests that a mean value for parasequence thickness is 17 m 56 ft mean parasequence sandstone fraction is 0 60 and mean shoreface sand body thickness is 8 m 26 ft the mean maximum parasequence progradation distance is 23 km 14 mi the results indicate that there are two critical controls that can significantly vary the parameter values stated above 1 stacked shoreline trajectory or systems tract and 2 shelf gradient the analyses indicate that shelf gradient is the most important parameter that has a first order control on parasequence properties shelf gradient in the ancient can be approximated to high gradient or low to moderate gradient categories via analysis of parasequence thickness change versus progradation distance from wells mean parasequence thickness or mean progradation distance from seismic attribute data parasequence progradation distance is to some degree predictable if stacked shoreline trajectory shelf gradient category and mean parasequence thickness are known the data suggest that there are two types of parasequences accommodation dominated and supply dominated parasequences the progradation distance of these parasequences are controlled by delta autoretreat mechanisms modulated by the combination of fifth and fourth order milankovitch scale orbitally forced climate change driven sediment supply cycles interacting with eustatically and tectonically driven accommodation cycles

on the geological significance of clastic parasequences abstract parasequences recognized in clastic sedimentary successions of shallow marine origin are considered by some geologists to be the fundamental building blocks of depositional sequences even though problems in their definition and application have been identified by others who instead advocate their abandonment as formal sequence stratigraphic units to elucidate the geological significance of clastic parasequences and inform the debate on their use in stratigraphy a quantitative characterization of the geometry facies characteristics and timescale of deposition of 1163 parasequences has been undertaken based on a synthesis of data from outcrop and subsurface studies that are available in the scientific literature through a database compilation the attributes of the studied parasequences are analysed with respect to the interpreted geological origin of the units and with consideration of sources of bias and uncertainty particular emphasis is placed on assessing the following i the importance of heuristics and of data types and coverage in the recognition of parasequences ii differences in parasequence characteristics observed across deltaic and shoreface depositional systems and between the quaternary and the ancient rock record iii possible explanations for the range in timescales of deposition of parasequences and iv the role of autogenic dynamics on the development of deltaic parasequences partly based on a comparison with the recent evolution of modern deltas the results demonstrate that parasequence definition and physical correlation suffer from subjectivity and that significant variability exists in the spatio temporal and architectural attributes of clastic parasequences this gives rise to uncertainty that affects the use of parasequences as a framework for comparison of the architecture of packages of strata originating via shoreline regression this uncertainty must be considered when using analogue data for subsurface predictions or when attempting comparative studies of clastic successions

precise tremor source locations and amplitude variations along the lower crustal central san andreas fault 1 we precisely locate 88 tremor families along the central san andreas fault using a 3d velocity model and numerous p and s wave arrival times estimated from seismogram stacks of up to 400 events per tremor family maximum tremor amplitudes vary along the fault by at least a factor of 7 with by far the strongest sources along a 25 km section of the fault southeast of parkfield we also identify many weaker tremor families which have largely escaped prior detection together these sources extend 150 km along the fault beneath creeping transitional and locked sections of the upper crustal fault depths are mostly between 18 and 28 km in the lower crust epicenters are concentrated within 3 km of the surface trace implying a nearly vertical fault a prominent gap in detectible activity is located directly beneath the region of maximum slip in the 2004 magnitude 6 0 parkfield earthquake

remote triggered seismicity caused by the 2011 m9 0 tohoku oki japan earthquake 1 seismic waves from large earthquakes have been shown to trigger seismicity large distances from a mainshock and this is termed remotely or dynamically triggered seismicity we performed a global search for seismicity potentially triggered by the seismic waves from the 2011 m9 0 tohoku oki japan earthquake using seismograms from global seismic networks and an event catalog we search for earthquakes and tremors instantaneously triggered during the passing of the seismic waves as well as for statistically significant changes in local and global seismic rates after the passing of the waves for earthquakes we find potential cases of instantaneous triggering in the united states russia china ecuador and mexico while for tremors we find evidence for triggering in taiwan armenia cuba and the united states in addition we observed a potential case of delayed triggering of larger magnitude earthquakes including a m5 2 in baja california mexico

quantitative outcrop data for flow simulation abstract an architectural analysis documents variations in bedding geometry and rock properties within a tide influenced deltaic sandstone exposed in the cretaceous frontier formation of central wyoming usa digital maps of bedding lithofacies and diagenetic cements as well as vertical logs of grain size lithofacies and permeability describe rock properties that potentially influence fluid flow behavior these records are used to construct simulation models that assess the relative importance of different types of geologic variability on prediction of subsurface fluid flow two 25 meter thick tide influenced deltaic sandstone bodies coarsen upward and contain inclined beds that reflect episodic delta front progradation decimeters to meters thick beds within bodies alternate between cross stratified sandstones formed during rapid flows and shales deposited during more quiescent conditions down depositional dip bed draping shales are more continuous and lithofacies within sandstone beds become finer grained and increasingly heterolithic as sandstone beds fine down dip mean permeability values decrease and coefficients of variation increase permeability values change from nearly normal distributions to highly right skewed and permeability values become more strongly spatially correlated nodular cements also affect permeability all of these variations were modeled using stratigraphic cornerpoint grids that preserve stratal geometry and gridblocks with properties assigned using a combination of rock property maps and statistical models based on rock property logs simulations predict effects on fluid flow of geologic heterogeneity at different scales the influences of process variables and the effects of different methods of grid construction and rock property assignment flow simulations of water flooding through a 22 m thick by 360 m long segment of a deltaic sandstone oil reservoir predict that 1 rapid flow through coarser grained deposits at the top of the sandstone body tends to draw water upward 2 thin shales draping sandstone beds shunt downdip directed flow downward and updip directed flow upward 3 cement nodules cause more tortuous flow patterns but have little effect on recovery efficiency 4 methods of predicting intrafacies correlation of permeability have little effect on flow behavior at this scale a simulation model constructed using a high resolution cartesian grid did not resolve the effects of inclined shales demonstrating the usefulness of stratigraphic cornerpoint grids for modeling flow through complex geologic deposits flow simulations of tracer flow through a meter thick cross stratified bed within the deltaic sandstone body showed that at this scale shale drapes and models of the intrafacies distribution of permeability have statistically significant effects

intra parasequence architecture of an interpreted asymmetrical wave dominated delta although modern wave dominated shorelines exhibit complex geomorphologies their ancient counterparts are typically described in terms of shoreface shelf parasequences with a simple internal architecture this discrepancy can lead to poor discrimination between and incorrect identification of different types of wave dominated shoreline in the stratigraphic record documented in this paper are the variability in facies characteristics high resolution stratigraphic architecture and interpreted palaeo geomorphology within a single parasequence that is interpreted to record the advance of an ancient asymmetrical wave dominated delta the standardville ab1 parasequence of the aberdeen member blackhawk formation is exposed in the book cliffs of central utah usa this parasequence and four others in the aberdeen member record the eastward progradation of north south trending wave dominated shorelines within the standardville ab1 parasequence distal wave dominated shoreface shelf deposits in the eastern part of the study area are overlain across a downlap surface by southward prograding fluvial dominated delta front deposits which have previously been assigned to a separate stranded lowstand parasequence formed by a significant allogenic change in relative sea level high resolution stratigraphic analysis of these deposits reveals that they are instead more likely to record a single episode of shoreline progradation characterized by alternating periods of normal regressive and forced regressive shoreline trajectory because of minor cyclical fluctuations in relative sea level interpreted normal regressive shoreline trajectories within the wave dominated shoreface shelf deposits are marked by aggradational stacking of bedsets bounded by non depositional discontinuity surfaces interpreted forced regressive shoreline trajectories in the same deposits are characterized by shallow incision of fluvial distributary channels and strongly progradational stacking of bedsets bounded by erosional discontinuity surfaces that record enhanced wave base scour fluvial dominated delta front deposits most probably record the regression of a lobate delta parallel to the regional shoreline into an embayment that was sheltered from wave influence wave dominated shoreface shelf and fluvial dominated delta front deposits occur within the same parasequence and their interpretation as the respective updrift and downdrift flanks of a single asymmetrical wave dominated delta that periodically shifted its position provides the most straightforward explanation of the distribution and relative orientation of these two deposit types

autostratigraphy a framework norm for genetic stratigraphy abstract autostratigraphy is the stratigraphy generated by large scale autogenic processes and needs to be heeded because of a current overreliance on allogenic controls in sequence stratigraphy key principles of autostratigraphy emerging from the theory of autoretreat and a new understanding of alluvial grade derive from the non equilibrium stratigraphic response i e the general lack of equilibrium configuration of depositional systems the non equilibrium behavior of fluvial deltas during times t of steady dynamic forcing leads to variable stratigraphic response that is the inevitable result of length d and time scaling particular to the depositional system rather than necessarily reflecting any sudden or unsteady change in the rate of allogenic forcing some abrupt breaks in the stratigraphic record are not necessarily associated with changes in allogenic conditions but can result from purely autogenic processes of the system when t is comparable to or longer than 1 the depositional system takes the non equilibrium large scale autogenic response 2 the superposition of autogenic and allogenic components of the forcing is prominently nonlinear and thus 3 sequence stratigraphic models that have been built on the assumption of equilibrium response are incorrect autostratigraphic analysis makes it possible to detect and identify complex autogenic responses and unsteady allogenic events in the stratigraphic record by quantifying a temporal change in the magnitude of d autostratigraphy thus functions as a norm for genetic stratigraphy

a global search for triggered tremor following the 2011 mw 9 0 tohoku earthquake abstract the 2011 m w 9 0 tohoku japan earthquake triggered deep tectonic tremor and shallow microearthquakes in numerous places worldwide here we conduct a systematic survey of triggered tremor in regions where ambient or triggered tremor has been previously identified tremor was triggered in the following regions south central alaska the aleutian arc shikoku in southwest japan the north island of new zealand southern oregon the parkfield cholame section of the san andreas fault in central california the san jacinto fault in southern california taiwan and vancouver island we find no evidence of triggered tremor in the calaveras fault in northern california one of the most important factors in controlling the triggering potential is the amplitude of the surface waves data examined in this study suggest that the threshold amplitude for triggering tremor is 0 1 cm s which is equivalent to a dynamic stress threshold of 10 kilopascals the incidence angles of the teleseismic surface waves also affect the triggering potentials of love and rayleigh waves the results of this study confirm that both love and rayleigh waves contribute to triggering tremor in many regions in regions where both ambient and triggered tremor are known to occur tremor triggered by the tohoku event generally occurred at similar locations with previously identified ambient and or triggered tremor further supporting the notion that although the driving forces of triggered and ambient tremor differ they share similar mechanisms we find a positive relationship between the amplitudes of the triggering waves and those of the triggered tremor which is consistent with the prediction of the clock advance model online material table of measured parameters and other information related to triggering nontriggering information and figures of observed seismograms

carbon isotope records from extant caribbean and south pacific sponges evolution of δ13c in surface water dic stable isotope records of demosponges from the caribbean and coral sea are described for the purpose of studying the influence of fossil fuel co2 on the carbon isotopic composition of dissolved inorganic carbon dic in surface water the slow growing sponges precipitate calcium carbonate in isotopic equilibrium with ambient sea water and are used to detect changes in 13cdic from pre industrial times early 19th century to the present we observed similar shapes and ranges in 13c curves measured on caribbean specimens collected from water depths of 25 84 and 91 m as well as a specimen collected in shallow waters off new caledonia the records reveal a highly significant correlation with atmospheric 13cco2 13cdic values for caribbean and coral sea surface waters were calculated using the 13c sponge records while 13c of atmospheric co2 decreased by about 1 4 from the early 19th century to 1990 13cdic of caribbean and coral sea surface waters decreased by 0 9 0 2 and 0 7 0 3 respectively no isotopic equilibrium between surface water dic and atmospheric co2 was observed either during the pre industrial steady state or during the last 100 years the lower amount of depletion in the surface water 13cdic with respect to the atmospheric anthropogenic signal is explained by the dilution of the surface waters by biologically altered subsurface water dic the lower 13c decrease in the coral sea points to a stronger influence of the subsurface water source compared to the caribbean

accommodation succession δa δs sequence stratigraphy observational method utility and insights into sequence boundary formation the future of sequence stratigraphy depends on stratigraphers making observations with a common method so that physical frameworks can be clearly separated from interpretations of driving mechanisms depositional sequence boundary selection is a well known controversy that could be resolved with objective recognition criteria accommodation succession sequence stratigraphy refines traditional methods using sedimentary facies facies associations vertical stacking stratal geometries and stratal terminations as the objective record of competing rates of accommodation change and sediment fill through time observations are placed in context of lateral transgression and regression and vertical aggradation and degradation movement of shoreline through time across multiple timescales in hierarchal stacks the repeating motif consists of a subaerial unconformity and its correlative subaqueous surface overlain in coastal settings by a basinward shift in coastal onlap and strata with progradational to aggradation stacking then retrogradation and aggradation progradation degradation stacking these stacking patterns are bounded by key surfaces recognized by stratal terminations and characteristic vertical successions of facies this pattern is independent of time duration or position on a sea level curve but incorporates data resolution regional extent and hierarchal stacking examples from multiple datasets show the utility and objectivity of the method and provide insights into sequence boundary formation

triggered seismic events along the eastern denali fault in northwest canada following the 2012 mw 7 8 haida gwaii 2013 mw 7 5 craig and two mw 8 5 teleseismic earthquakes we conduct a systematic search for remotely triggered seismic activity along the eastern denali fault edf in northwest canada an intraplate strike slip region we examine 19 distant earthquakes recorded by nine broadband stations in the canadian national seismograph network and find that the 2012 m w 7 8 haida gwaii and 2013 m w 7 5 craig alaska earthquakes triggered long duration 10 s emergent tremor like signals near the southeastern portion of the edf in both cases tremor coincides with the peak transverse velocities consistent with love wave triggering on right lateral strike slip faults the 2011 m w 9 0 tohoku oki and 2012 m w 8 6 indian ocean earthquakes possibly triggered tremor signals although we were unable to locate those sources in addition we also identify many short duration 5 s bursts that were repeatedly triggered by the rayleigh waves of the 2012 m w 7 8 haida gwaii earthquake although we were unable to precisely locate the short duration 5 s events they appear to be radiating from the direction of the klutlan glacier and from a belt of shallow historical seismicity at the eastern flank of the wrangell st elias mountain range the fact that these events were triggered solely by the rayleigh waves suggests a different source mechanism as compared with triggered tremor observed along the edf and other plate boundary regions online material description of rayleigh wave polarization detection figures of spectograms s wave amplitudes polarization analysis and static stress changes tables of earthquake catalogs and velocity model and animations of tremors and bursts

tremors along the queen charlotte margin triggered by large teleseismic earthquakes 1 we conduct a systematic search of tectonic tremors along the queen charlotte margin qcm in western canada triggered by distant earthquakes we identify triggered tremor as non impulsive high frequency signals coherent among several stations and coincident with passing surface waves so far the 2002 mw7 9 denali fault the 2004 mw9 2 sumatra and the 2011 mw9 1 tohoku oki earthquakes have triggered clear tremor in this region the 2010 mw8 8 maule chile and the 2012 mw8 6 sumatra earthquakes may have triggered but tremors in these two cases did not meet all of our criteria the triggered tremors are mostly located east of the queen charlotte fault in the southern portion of haida gwaii near the epicenter of the 28 october 2012 mw7 7 earthquake similar to the observations in other regions the triggered tremors were initiated by the love waves and continued during the subsequent rayleigh waves tremor bursts correlate with both the particle velocity and displacement of the love waves indicating they are triggered at either low angle thrust or vertical strike slip faults in addition we find that the triggering potential for the qcm is controlled by a combination of amplitude period and incident angles

interplay between shoreline migration paths architecture and pinchout distance for siliciclastic shoreline tongues evidence from the rock record facies geometry and key internal stratigraphic surfaces from eight cretaceous and eocene clastic shoreline tongues have been documented the regressive parts of all the studied tongues represent storm wave influenced strandplains deltas or fan deltas and the regressive shoreline trajectories varied from descending to ascending the transgressive parts of the tongues are dominated by either estuarine or coastal plain deposits the distance from the coeval up dip non marine deposits to the basinward pinchout of amalgamated shoreface sandstones measured along depositional dip is here termed the sand pinchout distance the study shows that the angle of regressive to transgressive turnaround defined by the angle between the regressive and subsequent transgressive shoreline trajectories and the process regime during turnaround largely control the sand pinchout distance the amount of transgressive erosion can also partly control the pinchout distance but this parameter was comparable for the different examples presented here if the type of depositional system at turnaround and the depth of transgressive erosion are constant small angles of turnaround are associated with large pinchout distances whereas larger angles of turnaround result in smaller pinchout distances the model developed allows sand pinchout distance to be predicted using data for the landward parts of shoreline tongues the dataset also shows that steeply rising aggrading shoreline trajectories tend to produce more heterolithic sandstone tongues than those formed by lower angle trajectories

tectonic tremor beneath cuba triggered by the mw 8 8 maule and mw 9 0 tohoku oki earthquakes we provide additional evidence of tectonic tremor in cuba triggered by the 2010 m w 8 8 maule chile and the 2011 m w 9 0 tohoku oki japan earthquakes the high frequency tremor signals are modulated by long period surface waves similar to triggered tremors observed in other tectonically active regions we are able to locate two tremor sources triggered by the tohoku oki earthquake near the east west trending oriente fault around guantanamo bay the tremor around guantanamo bay was triggered primarily by a love wave of the maule mainshock and by both love and rayleigh waves of the tohoku oki mainshock this is consistent with frictional failures at a vertical strike slip fault under a coulomb failure criterion online material figure of envelope functions of tremor records and movies of spectogram and tremor correlation

calcium isotope fractionation in calcite and aragonite abstract calcium isotope fractionation was measured on skeletal aragonite and calcite from different marine biota and on inorganic calcite precipitation temperatures ranged from 0 to 28 c calcium isotope fractionation shows a temperature dependence in accordance with previous observations 1000 ln cc 1 4 0 021 t c for calcite and 1000 ln ar 1 9 0 017 t c for aragonite within uncertainty the temperature slopes are identical for the two polymorphs however at all temperatures calcium isotopes are more fractionated in aragonite than in calcite the offset in 44 40 ca is about 0 6 the underlying mechanism for this offset may be related to the different coordination numbers and bond strengths of the calcium ions in calcite and aragonite crystals or to different ca reaction behavior at the solid liquid interface recently the observed temperature dependence of the ca isotope fractionation was explained quantitatively by the temperature control on precipitation rates of calcium carbonates in an experimental setting lemarchand et al 2004 we show that this mechanism can in principle also be applied to caco 3 precipitation in natural environments in normal marine settings following this model ca isotope fractionation in marine ca carbonates is primarily controlled by precipitation rates on the other hand the larger ca isotope fractionation of aragonite compared to calcite can not be explained by different precipitation rates the rate control model of ca isotope fractionation predicts a strong dependence of the ca isotopic composition of carbonates on ambient co 3 2 concentration while this model is in general accordance with our observations in marine carbonates cultured specimens of the planktic foraminifer orbulina universa show no dependence of ca isotope fractionation on the ambient co 3 2 concentration the latter observation implies that the carbonate chemistry in the calcifying vesicles of the foraminifer is independent from the ambient carbonate ion concentration of the surrounding water

detecting deep tectonic tremor in taiwan with a dense array abstract we perform a systematic detection of deep tectonic tremor beneath the southern central range in taiwan using a dense small aperture seismic array deployed in february 2011 the array has been recording tectonic tremor nearly continuously for 134 days including tremor triggered by the 2011 m w 9 0 tohoku oki earthquake we use broadband frequency wavenumber beamforming and moving window grid search methods to compute array parameters for all continuous data and identify tremor as coherent nonimpulsive seismic signals with deep incidence angles the obtained array parameters closely match with those of relocated local earthquakes and triggered tremor bursts located by the waveform envelope correlation and clustering wecc method indicating the robustness of our array technique during the 134 day study period we detect tremor for 44 days with a total duration of 1481 min three to six times as long as the detection of tremor by the wecc method we find a relative quiescence in ambient tremor activity for about 20 days following the 2011 tohoku oki earthquake suggesting that dynamic stresses from the distant mainshock triggered most tremor close to failure resulting in a temporary lack of tremor activity in some cases we observe rapid tremor migration with a speed at the order of 40 50 km hr that is similar to the speed of fast tremor migration along dip on narrow streaks in japan and cascadia our results suggest that dense array techniques are capable of capturing detailed spatiotemporal evolutions of tremor behaviors in southern taiwan online material tables of station coordinates and tremor event parameters and figures of the moving window grid search test with local earthquakes tremor triggered by the 2011 tohoku oki earthquake and additional examples of detected ambient tremors

overlapping faults and their effect on fluid flow in different reservoir types a lidar based outcrop modeling and flow simulation study in this article we focus on the potential of fault overlap zones as conduits for fluid flow in a variety of reservoir types light detection and ranging lidar technology were applied to collect a three dimensional spatially constrained data set from a well exposed fault overlap zone that crops out in the devil s lane area of the canyonlands national park in utah a virtual outcrop was generated and used to extract structural and stratigraphic data that were taken into a reservoir modeling software and reconstructed the outcrop based model was flow simulated and used to test fluid flow through a real world fault overlap zone a structural framework was built based on collected outcrop data and combined with a series of nine different facies models the different facies models included an eolian model based on the outcrop and a range of synthetic fluvial and shallow marine systems results show that for certain depositional models cross fault reservoir communication may be poor despite the geometric connectivity of the relay beds this was the case for low net gross fluvial models and shoreface models conversely high net gross fluvial systems and eolian systems show good communication through the same relay zone overall the results show that in the presence of a fault overlap zone pressure communication across a relay ramp may still be poor depending on the scale of the faults and relay ramp as well as the geometry and volume of the sands

biological control of calcium isotopic abundances in the global calcium cycle measurements of 44ca 40ca expressed as 44ca were made on igneous rocks and on shell and bone material from modern organisms to investigate the magnitude and origins of calcium isotopic fractionation in nature the results document a span of 4 in 44ca measured with the double spike technique to a precision of 0 15 volcanic rocks including basalt and rhyolite show little variability and cluster near 44ca 0 0 2 systematic analysis of biological samples indicates that biological processing of calcium discriminates against heavy isotopes and that biological fractionation is the primary generator of calcium isotopic fractionation in nature preliminary data suggest that calcium becomes isotopically lighter as it moves through food chains calcium carbonate shells of marine microorganisms and deep sea carbonate ooze have 44ca about 1 0 lower than seawater this fractionation causes seawater to be enriched in heavy calcium 44ca 0 9 relative to igneous rocks marine organisms consequently are isotopically heavier than their terrestrial counterparts at similar trophic level the calcium isotopic composition of living and fossil organisms may record information on diet and environment

reconstruction of caribbean sea surface temperature and salinity fluctuations in response to the pliocene closure of the central american gateway and radiative forcing using δ44 40ca δ18o and mg ca ratios the 18o values of planktonic foraminifera increased in the caribbean by about 0 5 relative to the equatorial east pacific values between 4 6 and 4 2 ma as a consequence of the closure of the central american gateway cag this increase in 18o can be interpreted either as an increase in caribbean sea surface mixed layer salinity sss or as a decrease in sea surface temperatures sst this problem represents an ideal situation to apply the recently developed paleotemperature proxy 44 40ca together with mg ca and 18o on the planktic foraminifer globigerinoides sacculifer from odp site 999 although differences in absolute temperature calibration of 44 40ca and mg ca exist the general pattern is similar indicating a sst decrease of about 2 3 c between 4 4 and 4 3 ma followed by an increase in the same order of magnitude between 4 3 and 4 0 ma correcting the 18o record for this temperature change and assuming that changes in global ice volume are negligible the salinity induced planktonic 18o signal decreased by about 0 4 between 4 4 and 4 3 ma and increased by about 0 9 between 4 3 and 4 0 ma in the caribbean the observed temperature and salinity trends are interpreted to reflect the restricted exchange of surface water between the caribbean and the pacific in response to the shoaling of the panamanian seaway possibly accompanied by a southward shift of the intertropical convergence zone itcz between 4 4 and 4 3 ma differences in mg ca and 44 40ca derived temperatures can be reconciled by corrections for secular variations of the marine mg casw and 44 40ca a salinity effect on the mg ca ratio and a constant temperature offset of 2 5 c between both sst proxy calibrations

an integrated perspective of the continuum between earthquakes and slow slip phenomena slow slip a mechanism by which faults can relieve stress was thought to be distinct from earthquakes however a global review of slow slip phenomena suggests that instead there is a continuum between the two types of event