source characteristics of the 28 september 2018 m w 7 5 palu sulawesi indonesia se asia earthquake based on inversion of teleseismic bodywaves we study source characteristics of the september 28 2017 mw 7 5 palu sulawesi indonesia earthquake that occurred in central sulawesi and triggered devastating tsunami waves along the coastal plains of the island we apply point source teleseismic p and sh body waveform inversion and kinematic slip inversion techniques to obtain double couple source mechanism and comprehensive finite fault slip model of the source the overall results show a strike slip faulting mechanism strike 353 5 dip 65 5 and rake angles 4 5 with a small amount of dip slip component at a shallow focal depth of 16 2 km associated with the nw se trending left lateral palu koro strike slip fault in the central sulawesi region the p wave first motion polarity readings recorded at near field and regional seismic stations are found to be reasonably consistent with the source mechanism solution of the earthquake and estimated error limits we have extensively studied and considered the rupture velocity to be about 4 1 km s during the slip inversion as previously proposed by seismological and geodetic studies for this event the obtained finite fault slip distribution model displays a rupture starting from the hypocentre located at 16 km and then it propagated south accompanied by high amount of displacement and reached the surface the model has two slip patches of 2 0 4 0 m at north of the fault plane and 5 0 6 3 m at south near palu city which is very well matched with the observed damage and destruction related to the earthquake the fault length and width average slip and stress drop values are estimated to be 150 km 45 km 1 5 m and 13 bars respectively we have also obtained total source duration to be about 40 s with the most of seismic energy released at 10 s and 25 s furthermore a small dip slip component is evidently observed from both source models and we suggest that this oblique shear which reflects the bending of slip vector along the strike direction could be comparatively responsible for tsunami generation along the left lateral palu koro fault the validation of this hypothesis could be done by evaluating the results of the mathematical tsunami simulations based on the comprehensive non uniform slip models along with a high resolution bathymetry data which provides the details of the continental shelf in palu bay

a study on the regulation of the concentrations of some trace metals rb sr zn pb cu v cr ni mn and mo in saanich inlet sediments british columbia canada abstract bulk metal concentrations were measured in the sediments of saanich inlet in an attempt to establish the occurrence of trace metal enrichment in the anoxic central basin ba ni v cr zn pb cu and mo were found to be enriched in the anoxic ooze over the possible contributions from lithogenic sources spatial and seasonal variations in the chemical composition of the settling particulates collected with interceptor traps gave further indications of the mode of incorporation of these metals biogenic ba and cr appeared to be associated with opaline silica although alternative explanations are also possible particularly for ba zinc seemed to be added to the sediment essentially in association with planktonic materials while cu required an additional source directly linked to the anoxic environment similarly ni v and mo were added to the anoxic sediments by reactions occurring at the sediment water interface in the nearshore environment studied here these metals particularly ni and mo were not associated to any significant extent with planktonic materials of all the elements analyzed mo showed the largest enrichment in the anoxic sediments of saanich inlet

the early diagenesis of submerged sulphide rich mine tailings in anderson lake manitoba the oxidation of sulphide rich mine tailings stored on land by acidophilic bacteria is frequently associated with severe environmental degradation as metal rich acid drainage from the tailings contaminates groundwater and surface runoff permanent storage of tailings underwater may prove to be more chemically benign if oxidation is inhibited sufficiently to assess this possibility the chemistry of interstitial waters and the associated solid phases in tailings and organic rich 20 30 wt c natural sediments in anderson lake manitoba is examined the lake has been used as a receiving basin for sulphide rich tailings since 1979 and is contaminated with metals as a result of the input of acid mine drainage along the north shore and the discharge of mill process water with the tailings three cores were collected and processed under nitrogen to extract interstitial waters at all sites the occurrence of high concentrations of dissolved iron in shallow pore waters indicates that the deposits are anoxi

the source mechanism and numerical modelling of the 1953 suva tsunami fiji abstract a study is presented on the cause of the destructive tsunami that struck suva city in 1953 following a moderate offshore earthquake ms 6 75 alternative earthquake and submarine landslide source mechanisms are modelled using the geowave tsunami simulation model and compared with observational reports a simulation using a 60 million cubic metre submarine landslide located at the head of the suva canyon 4 km to the wsw of suva city reproduces the observed run up the simulation shows that high variability in tsunami impact over short coastal distances of suva are attributable to the complex interplay of wave propagation with the barrier reef system variable lagoon bathymetry and irregularly shaped coastline the earthquake tsunami may have been responsible for the observed small warning wave which preceded the destructive tsunami waves initiated by the submarine landslide

guzhangian mid cambrian trilobites from siliceous concretions of the valtorres formation iberian chains ne spain in the carbonate siliciclastic strata of west gondwana e g in the montagne noire france the aftermath of the mid languedocian mid cambrian regression is characterized by a late languedocian major turnover of trilobite families and a furongian early tremadocian radiation related to the stepwise immigration of trilobite invaders from east gondwana under persistent transgressive conditions the scarcity of upper languedocian fossil accumulations in clayey substrates has inspired the sampling of the palaeogeographically most distal parts of the iberian chains spain where diagenetic dissolution of ubiquitous hexactinellid sponge spicules has favoured the formation of siliceous concretions these have yielded the trilobites peronopsis cf insignis oidalagnostus trispinifer proampyx difformis proampyx aculeatus bailiaspis glabrata holocephalina agrauloides by ontogeny holasaphus cf centropyge and a paradoxidid gen et sp indet despite preservation and sampling biases the identification of this taphonomic window in offshore clayey substrates of west gondwana allows the recognition of a strong biogeographical link with baltica and the correlation of the global guzhangian stage and the solenopleura brachymetopa zone of scandinavia with part of the mediterranean upper languedocian substage less

first results of a bathymetric survey of palu bay central sulawesi indonesia following the tsunamigenic earthquake of 28 september 2018 on 28 september 2018 a 7 7 mw strike slip earthquake struck central sulawesi at 0 18 s 119 85 e 10 km northwest of palu the capital of central sulawesi province affecting more than 230 000 people the rapid arrival of the wave suggests a tsunami source within palu bay a bathymetric campaign was conducted in palu bay and the region south of cape manimbaya from 9 to 18 october 2018 one of the goals was to identify a potential source for the tsunami the bathymetry data show a prominent submarine channel within palu bay with sinuosity controlled by the palu koro fault the submarine channel continues into deeper water south and west of cape manimbaya with a sinuosity index of up to 1 770 several submarine slumps were identified within the bay due to the arcuate head scarp the abrupt change in slope and debris on the seafloor or the undulating shape of the slope one possible source location near the mouth of palu bay is identified from the estimated volume of displaced sediment the bathymetry data also show traces of the palu koro fault and suggestions of uplift of cape manimbaya related to activity of the palu koro fault

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

a proposed nomenclature for stages and series for the cambrian of laurentia an internally consistent succession of six named regional stages from youngest to oldest sunwaptan steptoean marjuman delamaran dyeran montezuman with their boundaries defined by regional extinction events within the trilobite record is proposed for the trilobite bearing rocks of laurentia sub trilobite stage s are recommended but unnamed the three youngest stages have been named previously but the lower boundary of the marjuman is shifted downward the three older stages within the trilobite record are new if deemed necessary four regional series are also suggested from youngest to oldest millardan lincolnian waucoban and begadean each of the three youngest series accommodates two stages

a study of ground motion excitation based on the earthquake of september 8 2017 evidence that normal faults influence the stress parameter we performed a study of ground motion modeling based on multiple linear regression and random vibration theory using the earthquake sequence of september 8 2017 mw 8 2 our results show that there is high attenuation in the region of oaxaca chiapas and central mexico however the peak amplitude excitations of normal fault earthquakes are higher than those of thrust fault earthquakes the earthquake sequence involved a large number of events but not all the seismic events were aftershocks because many earthquakes had different rupture styles the thrust events follow a simple scaling relation with a constant stress parameter but the normal fault events are difficult to represent with a constant self similar model our best result consists of a q 0 240 pm 032 with a frequency dependent factor of 0 63 pm 0 05 the excitation term is well determined with a stress parameter of 80 bars for the thrust faults but for the normal faults the stress parameter is at least 180 bars with a non self similar model our results show that it is necessary to include new ground motion prediction equations in seismic hazard analysis for meganormal faults which have not previously been considered in subduction zones

integrated cambrian biostratigraphy and carbon isotope chemostratigraphy of the gronhogen 2015 drill core oland sweden the gronhogen 2015 core drilling on southern oland sweden penetrated 50 15 m of cambrian series 3 furongian and lower middle ordovician strata the cambrian succession includes the aleklinta member upper stage 5 of the borgholm formation and the alum shale formation guzhangian tremadocian agnostoids and trilobites allowed subdivision of the succession into eight biozones in ascending order the uppermost cambrian series 3 guzhangian agnostus pisiformis zone and the furongian olenus gibbosus o truncatus parabolina spinulosa sphaerophthalmus flagellifer ctenopyge tumida c linnarssoni and parabolina lobata zones conspicuous lithologic unconformities and the biostratigraphy show that the succession is incomplete and that there are several substantial gaps of variable magnitudes carbon isotope analyses 13corg through the alum shale formation revealed two globally significant excursions the steptoean positive carbon isotope excursion spice in the lower middle paibian stage and the negative top of cambrian excursion toce previously referred to as the herb event in stage 10 the 13corg chemostratigraphy is tied directly to the biostratigraphy and used for an improved integration of these excursions with the standard agnostoid and trilobite zonation of scandinavia their relations to that of coeval successions in baltoscandia and elsewhere are discussed the maximum amplitudes of the spice and toce in the gronhogen succession are comparable to those recorded in drill cores retrieved from scania southern sweden the results of this study will be useful for assessing biostratigraphic relations between shale successions and carbonate facies on a global scale less

organic degradation sulphate reduction and ammonia production in the sediments of loch eil scotland abstract the rates of degradation and mineralization of organic matter in sediments from two stations in loch eil were studied a particular feature of this site is a major input of cellulose fibre from a pulp and paper mill which affected both sediments and benthic fauna the input may be regarded as an additional terrigenous input having a high c n ratio the effect of this input on organic degradation sulphate reduction and ammonia production was determined in both field samples and using sediment incubation experiments the result of the cellulose input is a spatial condensation of the normal biogeochemical zones in the sediment bringing the sulphate reducing zone to the sediment surface at e70 the station receiving the highest input rates of sulphate reduction are comparable to those measured at other sea loch sites and differences between the rates of sulphate reduction measured by 35so42 technique and jar incubation are demonstrated alkalinity and ammonium production may be related to sulphate reduction by previously accepted stoichiometry and model calculations suggest that the organic matter being mineralized in the sulphate reducing zone has a c n ratio similar to that in marine planktonic material e70 7 e24 8 at e70 there is apparently production of ammonia in excess of that produced by sulphate reduction the potential for nitrate reduction to ammonia was demonstrated in the surface sediments degradation of cellulose which was active only in the near surface sediments was not related directly to sulphate reduction and it is suggested that this is due to production of organic intermediates and cell carbon only a percentage of the carbon being mineralized comparison of estimated inputs of organic carbon to the sediments with the turnover of sulphate suggests that sulphate reduction can account for degradation of an amount of carbon equivalent to the total estimated primary production in loch eil about half the total carbon input mineralization of carbon by aerobic and anaerobic processes appears to balance the estimated input of carbon but this does not account for the carbon content of the sediments up to 8 and it is suggested that net mineralization has been overestimated

tsunami fragility functions for road and utility pole assets using field survey and remotely sensed data from the 2018 sulawesi tsunami palu indonesia the 2018 sulawesi tsunami caused widespread impacts in palu city indonesia including to components of infrastructure lifeline networks lifeline networks are key to the operation of society and are particularly crucial during post disaster relief and recovery efforts understanding their vulnerability to tsunami hazards is important for disaster risk reduction but is an understudied topic this study uses field survey and remotely sensed data to develop a single dataset used to create tsunami fragility functions for road and utility pole assets in palu tsunami inundation depths were estimated at component locations from a spatial interpolation of field measured flow depths and wave run up component attributes and geometries exposed to tsunami inundation were compiled from both field surveys and remote sensing on satellite imagery and street view imagery which included component construction material capacity roads and height poles roads demonstrate a 0 16 probability of exceeding complete damage at 2 m inundation depth while utility poles see a 0 47 probability the probability of exceeding complete damage at 2 m inundation depth for concrete asphalt collector and local roads is 0 34 0 17 0 19 and 0 13 respectively and for concrete steel steel 5 m height utility poles is 0 42 0 48 0 49 and 0 47 respectively when comparing the synthesised tsunami fragility functions to those from other global events palu roads were more vulnerable at 2 m inundation depth 0 16 compared to roads exposed to the 2011 tohoku tsunami in japan 0 06 and 2015 illapel tsunami in chile 0 05

a lightweight gravity corer for undisturbed sampling of soft sediments a lightweight portable gravity corer is described that collects up to 3 m long 10 cm diameter undistrubed cores from sediments of exceptionally high porosity the corer employs a triple o ring seal to hold sediments in an unsupported catcher free plastic barrel simply by suction author

the 2018 mw7 5 palu supershear earthquake ruptures geological fault s multisegment separated by large bends results from integrating field measurements lidar swath bathymetry and seismic reflection data

insights on the source of the 28 september 2018 sulawesi tsunami indonesia based on spectral analyses and numerical simulations the 28 september 2018 sulawesi tsunami has been a puzzle because extreme deadly tsunami waves were generated following an mw 7 5 strike slip earthquake while such earthquakes are not usually considered to produce large tsunamis here we obtained processed and analyzed two sea level records of the tsunami in the near field pantoloan located inside the palu bay and far field mamuju located outside the palu bay and conducted numerical simulations to shed light on the tsunami source the two tide gauges recorded maximum tsunami trough to crest heights of 380 and 24 cm respectively with respective dominating wave periods of 3 6 4 4 and 10 min and respective high energy wave duration of 5 5 and 14 h the two observed waveforms were significantly different with wave amplitude and period ratios of 16 and 3 respectively we infer tsunamigenic source dimensions of 3 4 4 1 km and 32 5 km for inside and outside of the palu bay respectively our numerical simulations fairly well reproduced both tsunami observations in pantoloan and mamuju except for the arrival time in mamuju however it was incapable of reproducing the maximum reported coastal amplitudes of 6 11 m it is possible that these two sources are different parts of the same tectonic source a bay oscillation mode of 85 min was revealed for the palu bay through numerical modeling actual sea surface disturbances and landslide generated waves were captured by two video recordings from inside the palu bay shortly after the earthquake it is possible that a large submarine landslide contributed to and intensified the sulawesi tsunami we identify the southern part of the palu bay around the latitude of 0 82os as the most likely location of a potential landslide based on our backward tsunami ray tracing analysis however marine geological data from the palu bay are required to confirm such hypothesis

the middle cambrian cosmopolitan key species lejopyge laevigata and its biozone new data from sweden the middle cambrian lejopyge laevigata zone is poorly exposed in scandinavia both this zone however and the succeeding agnostus pisiformis zone are well exposed at a classic locality at gudhem vastergotland south central sweden the sequences consist of finely laminated alum shale with scattered stinkstone orsten lenses three measured and sampled sections yielded a diverse fossil fauna dominated by trilobites in particular agnostoids and the bradoriid anabarochilina primordialis fossils are excellently preserved but restricted to the stinkstones the l laevigata zone at gudhem includes several geographically widespread key agnostoid species notably tomagnostella sulcifera clavagnostus spinosus glaberagnostus altaicus lejopyge laevigata and l armata the l laevigata zone in scandinavia is here extended to include the traditional solenopleura brachymetopa zone and its lower boundary is defined by the fad of l laevigata trilobite evidence shows that the upper part of the scandinavian l laevigata zone approximately correlates with the proagnostus bulbus zone of china and elsewhere less

rare earth elements in saanich inlet british columbia a seasonally anoxic basin rare earth element and manganese distributions have been investigated in saanich inlet british columbia a seasonally anoxic basin redox cycling of ce and mn takes place across an oxic suboxic boundary approximately 20 m shallower than the o2h2s interface the remaining strictly trivalent ree undergo scavenging above this oxic suboxic boundary and regeneration from dissolving host phases below it these processes result in pronounced removal of ce from solution above the oxic suboxic boundary due to oxidative precipitation along with preferential uptake of the lighter trivalent ree during scavenging below the oxic suboxic boundary regeneration of particulate ree into solution leads to a less pronounced ce depletion and a less pronounced hree enrichment in the anoxic bottom waters dissolved ree concentrations in the sediment pore waters exhibit an approximately ten fold increase across the seawater sediment interface but then decrease with increasing depth indicating removal from solution during later diagenesis calculated diffusive fluxes of the ree and mn from the sediments into the overlying anoxic water column are insufficient to account for the accumulated trace metal enrichments observed in the water column we propose an annual redox cycle for saanich inlet in which flushing causes extensive oxidative precipitation and scavenging of trace elements from the water column each autumn the same material is rapidly regenerated from the underlying near surface sediments when the basin next turns anoxic

early diagenesis of copper and molybdenum in mine tailings and natural sediments in rupert and holberg inlets british columbia the distribution and behaviour of cu and mo in interstitial waters collected from cu and mo rich mine tailings and natural sediments in rupert and holberg inlets vancouver island british columbia are discussed dissolved fe mn and h2s distributions and solid phase cu mo mn and organic carbon data are used to constrain the interpretation of cu and mo diagenesis in both tailings and natural sediment facies cu is released to solution at or near the sediment water interface in both facies either by decomposing labile organic material or as a probable result of oxidation of sulphide minerals within the tailings mo is significantly enriched up to 0 6 mol l 1 in tailings pore water probably as a result of dissolution of soluble mo oxides produced initially by oxidation of mos2 during milling of the ore in natural sediments both cu and mo are removed from solution at depth probably by precipitation as their sulphides or in solid solution with an iron sulphide phase similar reactions appear t

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

a study of sulphur enrichment in the humic fraction of marine sediments during early diagenesis abstract the evolution of the sulphur content of humic acids extracted from a near shore sediment core was investigated special attention was taken to avoid s contamination of the humic materials during extraction the s c ratios increased continuously with depth to values which strongly suggest s addition to the humic matrix during early diagenesis by reactions between organic matter and h2s or its oxidation products their light isotopic composition supports this view however subsequent isotopic exchange has obscured the mechanism initially involved since a large fraction of the enrichment occurred above the sulphidic zone redox boundaries such as the interface of anoxic microniches within more oxidized zones or the sulphidic suboxic boundary of the sediment column must have been important sites for s addition bioturbation by increasing the contact between sedimentary zones of a different redox regime will likely enhance such processes

field survey of the 2018 sulawesi tsunami deposits on 28 september 2018 a mw 7 5 earthquake struck sulawesi island soon followed by a destructive tsunami this study provides a case history of tsunami deposition where submarine landslides or coastal collapses have contributed to and intensified tsunami generation the sedimentary features resulting from this complex tsunami mechanism are not yet well understood we surveyed tsunami deposits at six locations along the coastline of palu bay in addition to measuring tsunami flow depth run up height and inundation distance at each site in general the tsunami height was less than 8 m with a maximum inundation distance of 310 m the tsunami deposits are thin with simple sedimentary structures such as fining upward sequences these sedimentary characteristics are typical of tsunami deposits elsewhere around the world this work is a preliminary study in that numerical modeling including sediment transport has not been performed further work is needed to distinguish tsunamis with different source mechanisms