the lamongan volcanic field east java indonesia physical volcanology historic activity and hazards abstract the lamongan volcanic field lvf in east java indonesia consists of up to 61 basaltic cinder or spatter cones a minimum of 29 prehistoric maars and a central compound complex comprising three main vents including the historically active lamongan volcano the field lies on the sunda volcanic arc and abuts onto the currently active tengger caldera semeru complex to the west between 1799 and 1898 lamongan was persistently active and discharged up to 15 lava flows of basaltic to basaltic andesite composition which is probably more than what was erupted by any other indonesian volcano in that period several seismic crises have been recorded in the lvf since lamongan s last eruption there are no existing records of cinder cone or maar forming eruptions in the area despite the possible hazards posed by future activity in the lvf the history and structure of the field have been subject to little scrutiny this contribution presents the results of a detailed morphometric and volumetric investigation of prehistoric vents and historic lava flows in the lvf using field data historic records satellite imagery and modelling of erupted volumes a typical lvf maar is characterised as a crater with a diameter of 450 m generated by an eruption with a model ejecta volume of 0 016 km 3 dense rock equivalent dre and a model juvenile component volume of 0 0096 km 3 dre diameter depth ratios of some maars display a morphological freshness comparable to recently formed phreatomagmatic eruption craters elsewhere the median lvf cinder spatter cone has a basal diameter of 600 m a height of 75 m a volume of 0 009 km 3 and a model total erupted volume of 0 014 km 3 variation in cone basal diameter to height ratios indicates that the age of some prehistoric cones may not exceed a few centuries and morphological classification identifies the youngest prehistoric vents on the northern flanks of the central edifice historic activity from vents on the western flanks of lamongan produced at least 0 05 km 3 of basaltic to basaltic andesite lava resurfacing rates at lamongan in the 19th century imply an age of 900 2100 years for the surface of the volcano the steady state eruptive rate from 1843 1898 is evaluated as 0 025 m 3 s 1 which is low in comparison to estimates from many presently active systems using eruptive rate and volume data the age of the lvf is estimated as between 13 and 40 ka placing it among the youngest dated indonesian volcanoes complex regional tectonics in conjunction with magmatic pressure have probably been the major influences on the distribution of volcanism in the lvf the occurrence of maar forming eruptions may have been controlled by a porous substrate possibly a deposit from the holocene iyang argapura complex to the east volcanic hazards from future eruptions in the lvf include base surges ash flows ashfall and ejected blocks associated with phreatomagmatic activity and ashfall and ejecta from magmatic eruptions

modeling the tor dotted crests bedrock edges and parabolic profiles of high alpine surfaces of the wind river range wyoming abstract broad low curvature surfaces common to many alpine landscapes and particularly well expressed in the laramide ranges of the western usa appear to be roughly in steady state with respect to the current surface processes uniform thin order 1 m regolith covers the crystalline bedrock with the exception of occasional tors at ridgecrests the surfaces are commonly edged by bedrock lips at the tops of cliffs that bound the intervening glacial troughs regolith production is low order 10 m year on bare bedrock and reaches a maximum under tens of centimeters of regolith all of these characteristics may be accounted for with a numerical model that is faithful to the periglacial surface processes presently operating on these surfaces hillslope transport is modeled assuming the dominant process is frost creep transport efficiency depends linearly upon local slope and appropriately vanishes in the absence of regolith frost frequency scales the rate of motion while the ratio of frost penetration depth to regolith thickness dictates the degree to which the process is curtailed by available regolith initial conditions include initial mean slope and bedrock roughness and a uniform regolith cover boundary conditions are imposed by dictating that the edges of the calculation space be lowered at a rate appropriate for glacial incision broad convex surfaces emerge over time scales of order 1 million years all surfaces rapidly decouple from the bounding glacial troughs as the high negative curvature at the edges disallows accumulation of regolith these bedrock edges lower at a few microns per year while the troughs lower at many times this rate as the bedrock edges therefore serve as the effective boundary condition for the remaining surface the surfaces operate independently of both lowering and widening of the glacial troughs for a reasonable set of transport and weathering rates the final steady state landscape is sensitive to the initial condition in particular the steeper the initial landscape the more likely tors are to develop as the high curvature disallows accumulation of regolith these tors in turn limit the lowering rate of the crest and the landscape retains significant local relief low relief initial conditions more likely lead to parabolic surfaces that lack tors that tors are more likely on the crests reflects the high initial curvature at the crest tors on the side slopes are eliminated the present high surfaces in the laramide ranges of the western usa imply operation of periglacial surface processes over millions of years the occasional tors imply a steeper rather than flatter initial landscape the strong decoupling of surfaces from glacial troughs justifies their use as local geomorphic markers that allow calculation of relief production since glacial incision was initiated on the other hand their present low curvature does not require a landscape history in which these surfaces were once joined as an initially widespread erosion surface

the lusi mud volcano triggering controversy was it caused by drilling abstract following the yogyakarta earthquake on may 27th 2006 the subsequent eruption of a mud volcano has been closely observed and analyzed by the geological community the mud volcano known as lusi began erupting near the banjarpanji 1 exploration well in sidoarjo east java indonesia lusi offers a unique opportunity to study the genesis and development of a mud volcano for the first time this paper presents all raw and interpreted drilling data so any interested party can perform their own assessment our study suggests that lusi mud volcano was a naturally occurring mud volcano in an area prone for its mud volcanism pressure analysis done on the banjarpanji well shows that the pressure exerted at the well is lower than the fracture pressure at the last casing shoe and suggests that the well was intact and did not suffer an underground blowout this is further supported by evidence and observation made during drilling such as circulation was done on an open bop and subsequent relief wells sonan and temperature log runs this study offers a different alternative to earlier hypothesis that events at the banjarpanji well were the trigger for the lusi mud volcano more work is needed by the scientific community to study the sequence of events in order to explain and clarify the real trigger of lusi

triggering and dynamic evolution of the lusi mud volcano indonesia abstract mud volcanoes are geologically important manifestations of vertical fluid flow and mud eruption in sedimentary basins worldwide their formation is predominantly ascribed to release of overpressure from clay and organic rich sediments leading to impressive build up of mud mountains in submarine and subaerial settings here we report on a newly born mud volcano appearing close to an active magmatic complex in a backarc sedimentary basin in indonesia the location of the mud volcano close to magmatic volcanoes results in a high background temperature gradient that triggers mineralogical transformations and geochemical reactions at shallow depth the eruption of 100 c mud and gas that started the 29th of may 2006 flooded a large area within the sidoarjo village in northeast java thousands of people have so far been evacuated due to the mud flood hazards from the eruption since the initial eruption the flow rate escalated from 5000 to 120 000 m 3 d during the first eleven weeks then the erupted volume started to pulsate between almost zero and 120 000 m 3 d in the period august 14 to september 10 whereas it increased dramatically following swarms of earthquakes in september before reaching almost 180 000 m 3 d in december 2006 sampling and observations were completed during two fieldwork campaigns on the site the eruption of boiling water is accompanied by mud aqueous vapour co 2 and ch 4 based on geochemical and field results we propose a mechanism where the eruptions started following the 27th of may earthquake due to fracturing and accompanied depressurization of 100 c pore fluids from 1700 m depth this resulted in the formation of a quasi hydrothermal system with a geyser like surface expression and with an activity influenced by the regional seismicity

glacially induced organization of channel reach morphology in mountain streams 1 we examine the spatial distribution of channel reach morphologies in formerly glaciated mountain drainage basins of coastal british columbia canada using field and geographic information systems derived data we show that the local channel slope and the degree of colluvial alluvial coupling imposed by the glacial valley morphology dictate the spatial organization of channel types in particular the complex glacially induced channel long profile produces characteristic sequences of channel reaches that depart from the downstream succession colluvial boulder cascade step pool rapids riffle pool distinctive of simple unglaciated mountain streams typically the presence of one hanging valley in the river long profile produces and separates two full successions of channel types a headmost one characterized by an ephemeral seasonal hydrologic regime and a downstream one where water runoff is perennial we document that channel types are well separated in plots of slope versus shear stress area versus shear stress and slope versus relative roughness in agreement with these outcomes multivariate discriminant analyses coupled with principal component analysis of 98 study reaches yield a highly successful channel type classification when slope shear stress and relative roughness are considered success rates depending on whether or not boulder cascade reaches are pooled together with step pools are 88 and 75 respectively previous work in unglaciated settings has suggested that mountain channels have distinct bed morphology states that vary primarily with slope our study reveals that even in formerly glaciated valleys where slope is largely inherited from glacial times these distinct bed states exist and vary mostly with slope adding considerable strength to this empirical knowledge

ground deformation associated with the eruption of lumpur sidoarjo mud volcano east java indonesia abstract ground deformation associated with the eruption of lumpur sidoarjo mud volcano between 2006 and 2011 has been investigated from synthetic aperture radar images marked subsidence has been observed to the west of as well as around the vent line of sight changes in the both areas decayed since the middle of 2008 with a time constant of 1 5 2 5 years implying that the ongoing eruption won t last long this uniform decay time indicates that the western part is connected to the eruption center since the middle of 2008 to form a system with stationary geometry our observation that the decay started later to the west than around the vent suggests that the subsidence to the west has been triggered by the mud eruption a simple modeling suggests that 1 the conduit needs to be narrower at depth than at the surface 2 the effective rigidity of the mud needs to be lower than that estimated from the drilled sample or both to explain the observed decay constant of the deformation

structure and evolution of hydrothermal vent complexes in the karoo basin south africa the karoo large igneous province formed at c 183 ma is characterized by the presence of voluminous basaltic intrusive complexes within the karoo basin extrusive lava sequences and hydrothermal vent complexes these last are pipe like structures up to several hundred metres in diameter piercing the horizontally stratified sediments of the basin detailed mapping of two sediment dominated hydrothermal vent complexes shows that they are composed of sediment breccias and sandstone the breccias cut and intrude tilted host rocks and are composed of mudstone and sandstone fragments with rare dolerite boulders sandstone clasts in the breccias are locally cemented by zeolite which represents the only hydrothermal mineral in the vent complexes our data document that the hydrothermal vent complexes were formed by one or a few phreatic events leading to the collapse of the surrounding sedimentary strata we propose a model in which hydrothermal vent complexes originate in contact metamorphic aureoles around sill intrusions heating and expansion of host rock pore fluids resulted in rapid pore pressure build up and phreatic eruptions the hydrothermal vent complexes represent conduits for gases and fluids produced in contact metamorphic aureoles slightly predating the onset of the main phase of flood volcanism

gas seepage from tokamachi mud volcanoes onshore niigata basin japan origin post genetic alterations and ch4 co2 fluxes abstract methane and co 2 emissions from the two most active mud volcanoes in central japan murono and kamou tokamachi city niigata basin were measured in from both craters or vents macro seepage and invisible exhalation from the soil mini and microseepage molecular and isotopic compositions of the released gases were also determined gas is thermogenic 13 c ch4 from 32 9 to 36 2 likely associated with oil and enrichments of 13 c in co 2 13 c co2 up to 28 3 and propane 13 c c3h8 up to 8 6 suggest subsurface petroleum biodegradation gas source and post genetic alteration processes did not change from 2004 to 2010 methane flux ranged within the orders of magnitude of 10 1 10 4 g m 2 d 1 in macro seeps and up to 446 g m 2 d 1 from diffuse seepage positive ch 4 fluxes from dry soil were widespread throughout the investigated areas total ch 4 emission from murono and kamou were estimated to be at least 20 and 3 7 ton a 1 respectively of which more than half was from invisible seepage surrounding the mud volcano vents at the macro seeps co 2 fluxes were directly proportional to ch 4 fluxes and the volumetric ratios between ch 4 flux and co 2 flux were similar to the compositional ch 4 co 2 volume ratio macro seep flux data in addition to those of other 13 mud volcanoes supported the hypothesis that molecular fractionation increase of the bernard ratio c 1 c 2 c 3 is inversely proportional to gas migration fluxes the ch 4 emission factor total measured output divided by investigated seepage area was similar to that derived in other mud volcanoes of the same size and activity the updated global emission factor data set now including 27 mud volcanoes from different countries suggests that previous estimates of global ch 4 emission from mud volcanoes may be significantly underestimated

hydrothermal petroleum genesis migration and deposition in guaymas basin gulf of california hydrothermal activity and seabed mounds have been explored in guaymas basin by the deep sea drilling project dsdp piston coring dredging and diving with the deep submersible research vessel dsrv alvin sedimentary organic matter derived primarily from immature degraded microbial detritus is easily converted to petroleum under the hydrothermal regime these petroleums are mature and migrate in the fluids and by diffusion to the seabed the fluid migration is aided by near critical aqueous solution and supercritical carbon dioxide and hydrocarbons petroleum compositions vary from condensates to naphthenic to waxy all with significant amounts of asphaltenes and hydrothermal products such as olefins and toxic polynuclear aromatic hydrocarbons pah the heavy ends condense at the seabed depositing mainly as a cement with the sulfides and other minerals and to a lesser extent as entrapped oil and crystalline wax in vugs and conduits of the mounds the pah are high temperature resynthesis aromatiza

volcanic activity influenced by tectonic earthquakes static and dynamic stress triggering at mt merapi 1 mt merapi is one of the most dangerous volcanoes in indonesia located within the tectonically active region of south central java this study investigates how mt merapi affected and was affected by nearby tectonic earthquakes in 2001 a mw6 3 earthquake occurred in conjunction with an increase in fumarole temperature at mt merapi in 2006 another mw6 3 earthquake took place concomitant with an increase of magma extrusion and pyroclastic flows here we develop theoretical models to study the amount of stress transfer between the earthquakes and the volcano showing that dynamic rather than static stress changes are likely responsible for the temporal and spatial proximity of these events our examination of the 2001 and 2006 events implies that volcanic activity at mt merapi is influenced by stress changes related to remote tectonic earthquakes a finding that is important for volcano hazard assessment in this densely inhabited area

modeling study of growth and potential geohazard for lusi mud volcano east java indonesia abstract the mud volcano known as lusi first erupted in may 2006 in east java indonesia the eruption has continued for over two years and potentially will continue for many years to come impacting an ever larger area an obvious and significant question is how extensive the impacted area will become in the coming years the answer is important for planning scenarios for the relocation of people and infrastructure and for managing the environment and economy to make such a prediction an understanding of the geological processes controlling the mud volcanic evolution is needed a three dimensional simulation model was built to predict the area affected by the mudflow over a ten year period with a special focus on the period from december 2007 until june 2010 the primary model inputs are the mud debit rate the rate of subsidence and the topography the model prediction was validated at the december 2007 time step by comparing the results with satellite images from the same period the simulation was found to provide a good approximation for the mud overflow and growth the results indicate that the mudflow tends to spread to the west and particularly to the east and north from the currently inundated area the model predicts that in june 2010 the peak of the mud volcano will have risen 26 m above the original ground level and the maximum subsidence will have been 63 m below the original ground level the dynamic subsurface condition in the area creates geohazard risks and these are also discussed in this paper

detection of southward intracontinental subduction of tibetan lithosphere along the bangong nujiang suture by p to s converted waves teleseismic primary p to secondary s converted waves recorded on the indepth iii seismic array have been used to detect lithospheric scale deformation structures of the central tibetan plateau from the central lhasa terrane to the central qiangtang terrane a south dipping crustal converter is seen from the upper crust near the 500 km long metamorphic core complex exposures in the qiangtang terrane to the lower crust near the bangong nujiang suture at deeper depths a southeast dipping mantle converter is seen extending from 50 km north of the bangong nujiang suture at the depth of the moho to a depth of 180 km 100 km south of the bangong nujiang suture we found the observations to be most consistent with a model of lithospheric deformation involving 1 southward subduction of the tibetan lithospheric mantle along the bangong nujiang suture and 2 thickening of the central tibetan crust through a thick skinned crustal accretionary thrust wedge structure in response to the india9s collision with asia

seismic sequence analysis and reservoir potential of drowned miocene carbonate platforms in the madura strait east java indonesia seismic analysis of four miocene carbonate buildups the porong ke 11c kd 11e and bd buildups in the madura strait region indonesia shows that they are constructed of four seismic units 1 4 all the buildups are located atop an east west trending oligocene fault block which through its uplift favored the deposition and aggradation of shoal water carbonates aggradation platform narrowing and backstepping of leeward reefs into the upper parts of individual buildups typify the growth profiles adjacent off buildup sedimentary rocks deposited at the same time as the buildups show clear horizontal onlap relationships in combination these observations imply that all the platforms were drowned the uppermost parts unit 4 of each of four major drowned buildups in the trend have been drilled to test for the presence of hydrocarbons an analysis of the drilling results in combination with our seismic analysis shows that those buildups that have relatively high levels of hydrocarbons have suitable trap configurations but lack seal integrity for example compactionally induced strain and gravitational gliding created leaky collapse graben faults extensional structures atop some buildups porong ke 11c which allowed hydrocarbons to drain likewise the updip inclination of some potential seal beds facilitated leakage ke 11e in terms of potential targets in similar drowned buildups in the region higher priority should be given to targets that 1 show evidence of ongoing platform backstepping and so called give up reef growth profiles associated with incipient drowning 2 contain all four seismic units units 1 4 in the buildup 3 lack an extensional collapse graben over the crest of the drowned structure and 4 demonstrate bed inclinations in the sealing beds that indicate likely closure over the crest of the buildup begin page 214

influence of seismicity on the lusi mud eruption earthquakes trigger the eruption of mud and magmatic volcanoes and influence ongoing eruptive activity one mechanism that could trigger an eruption is clay liquefaction here we model the propagation of seismic waves beneath the lusi mud eruption east java indonesia using available seismic velocity and density models to assess the effect of subsurface structure on the amplification of incident seismic waves we find that using an updated subsurface density and velocity structure there is no significant amplification of incident seismic energy in the upper kalibeng formation the source of the erupting solids hence the hypothesis that the lusi eruption was triggered by clay liquefaction appears unlikely to be correct independent constraints from gas chemistry as well as analyses of drilling activities at the nearby banjar panji 1 gas exploration well and an analysis of the effects of other earthquakes all favor a drilling trigger

controls on the channel width of rivers implications for modeling fluvial incision of bedrock on the basis of the manning equation and basic mass conser vation principles we derive an expression for scaling the steady state width w of river channels as a function of discharge q channel slope s roughness n and width to depth ratio a w 5 a a1 2 2 3 3 8 q 3 8 s 23 16 n 3 8 we propose that channel width to depth ratio in addition to roughness is a function of the material in which the channel is developed and that where a river is con fined to a given material width to depth ratio and roughness can be assumed constant given these simplifications the expression emulates traditional width discharge relationships for rivers incis ing bedrock with uniformly concave fluvial long profiles more sig nificantly this relationship describes river width trends in terrain with spatially nonuniform rock uplift rates where conventional discharge based width scaling laws are inadequate we suggest that much of observed channel width variability in river channels confined by bedrock is a simple consequence of the tendency for water to flow faster in steeper reaches and therefore occupy smaller channel cross sections we demonstrate that using conventional scaling relationships for channel width can result in underestima tion of stream power variability in channels incising bedrock and that our model improves estimates of spatial patterns of bedrock incision rates

morphological changes of gumara river channel over 50 years upper blue nile basin ethiopia summary in response to anthropogenic disturbances alluvial rivers adjust their geometry the alluvial river channels in the upper blue nile basin have been disturbed by human induced factors since a longtime this paper examines channel adjustment along a 38 km stretch of the gumara river which drains towards lake tana and then to the blue nile over a 50 years period agriculture developed rapidly in the catchment and flooding of the alluvial plain has become more frequent in recent times the objectives of this study were to document the changes in channel planform and cross section of the gumara river and to investigate whether the changes could have contributed to the frequent flooding or vice versa two sets of aerial photographs 1957 and 1980 were scanned and then orthorectified recent channel planform information was extracted from spot images of 2006 and google earth channel planform and bed morphology vertical changes were determined for these nearly 50 years period the vertical changes were determined based on aggradation along a permanent structure historic information on river cross sections at a hydrological gauging station and field observations the results indicate that the lower reach of gumara near its mouth has undergone major planform changes a delta with approx 1 12 km 2 of emerged land was created between 1957 and 1980 and an additional 1 km 2 of land has been added between 1980 and 2006 the sinuosity of the river changed only slightly negatively 1 1 i e meandering decreased for the period from 1957 to 1980 and positively 3 0 for the period 1980 2006 comparison of cross sections at the hydrological gauging station showed that the deepest point in the river bed aggraded by 2 91 m for the period 1963 2009 the importance of sediment deposition in the stream and on its banks is related to land degradation in the upper catchment and to artificial rising of lake tana level that creates a backwater effect and sediment deposition in gumara river direct anthropogenic impacts irrigation activities and building of dykes along the river banks have contributed to the huge deposition in the river bed where the abstraction of water for irrigation is intensive seepage water through the banks has contributed to river bank failure in general this study showed that changes to the planform at the mouth of the river and to the riverbed level are substantial moreover the study indicated that the flood carrying capacity of the gumara river channel has diminished in recent times

constraints on density changes in the funnel shaped caldera inferred from gravity monitoring of the lusi mud eruption abstract from its inception may 29 2006 the lusi mud eruption has continuously erupted fluids boiling mud and clasts through large active vents approximately 100 m in diameter in 2016 we conducted a dynamic gravity survey dg using a network built over four locations and two continuous gravity monitoring cg experiments to monitor the eruption activity the cg was done for 8 days from june 2nd to june 10th and for 9 days from august 20th to august 29th 2016 atmospheric pressure and atmospheric temperature variations were recorded during each experiment to constrain potential environmental effects and earth and oceanic tide effects were removed from gravity signals cg and dg atmospheric pressure effects were removed from cg gravity signals at the station closest to the hydrothermal pond the dg survey results show a gravity increase of 0 009 mgal month 1 which we interpret as the growth of the mud edifice in the central area cg monitoring shows that gravity variations occur at a period of 12 13 h with amplitudes reaching up to 0 020 mgal we interpret this as relating to density variation of the rising mud mixture fluids coarse mud clasts the observed 12 13 h period variations appear to indicate that tides may have some control on the density change of rising mud mixture by triggering the release of gas trapped at depth our 3d gravity results around the lusi vents show that density variations range from 100 kg m 3 to 775 kg m 3 similarly vent diameters better constrain density contrasts occurring within the caldera zone which is more likely to range between 400 and 450 kg m 3 and is equivalent respectively to 27 and 31 of gas ratio change over time

evolution and future of the lusi mud eruption inferred from ground deformation 1 the ongoing eruption of the lusi mud volcano in east java indonesia offers the unprecedented opportunity to study a large eruption from its beginning to its eventual end we use new observations of ground deformation obtained from multitemporal interferometric analysis of l band synthetic aperture radar data to show that lusi will stop erupting much sooner than previously anticipated using principal component analysis we find that the rate of ground deformation and by implication pressure in the mud source region has been decaying exponentially with an e folding time scale of 2 1 0 4 years we anticipate that discharge will decrease to 10 of the present rate in 5 years

landscape response to tectonic forcing digital elevation model analysis of stream profiles in the mendocino triple junction region northern california the topographic evolution of orogens is fundamentally dictated by rates and patterns of bedrock channel incision quantitative field assessments of process based laws are needed to accurately describe landscape uplift and denudation in response to tectonics and climate we evaluate and calibrate the shear stress or similar unit stream power bedrock incision model by studying stream profiles in a tectonically active mountain range previous work on emergent marine terraces in the mendocino triple junction region of northern california provides spatial and temporal control on rock uplift rates digital elevation models and field data are used to quantify differences in landscape morphology associated with along strike northwest to southeast changes in tectonic and climatic conditions analysis of longitudinal profiles supports the hypothesis that the study area channels are in equilibrium with current uplift and climatic conditions consistent with theoretical calculations of system response time based on the shear stress model within uncertainty the profile concavity of the trunk streams is constant throughout the study area 0 43 as predicted by the model channel steepness correlates with uplift rate these data help constrain the two key unknown model parameters the coefficient of erosion k and the exponent associated with channel gradient n this analysis shows that k cannot be treated as a constant throughout the study area despite generally homogeneous substrate properties for a reasonable range of slope exponent values n best fit values of k are positively correlated with uplift rate this correlation has important implications for landscape evolution models and likely reflects dynamic adjustment of k to tectonic changes due to variations in orographic precipitation and perhaps channel width sediment load and frequency of debris flows the apparent variation in k makes a unique value of n impossible to constrain with present data

cyclic activity of mud volcanoes evidences from trinidad se caribbean fluid and solid transfer in mud volcanoes show different cyclic phases of activity including catastrophic events and periods of relative quiescence characterized by moderate activity this is notably well shown by the compilation of historical data onshore trinidad it appears that each eruptive mud volcano has its own period of catastrophic activity and this period is variable from one volcano to another the frequency of the eruptions seems essentially controlled by local pressure regime within the sedimentary pile the dynamics of expulsion of the mud volcanoes during the quiescent phases has been studied with the help of temperature measurements within the mud conduits the mud temperature in these conduits is notably concurrently controlled by the gas flux endothermic gas depressurizing induces a cooling effect and by the mud flux mud is a vector for convective heat transfer complex temperature distribution was observed in large conduits and pools especially in the bigger pools the temperature distribution characterizes convective cells with an upward displacement of mud above the deep outlet and ring shaped rolls associated with the burial of the mud on the flanks of the pools in tube like shaped narrow conduits the temperature is more regular but we observed different types of profiles with either downward increasing or decreasing temperatures near constant to even negative gradients compared to the general temperature gradient are typical for very dynamic fluid systems the temperature profiles varied from one place to another as well as over time the temperatures measured within the conduits and their base show that the fluid flow is not constant but highly variable through short time periods we observed locally a significant daily change of the temperature of the expelled mud which shows also that the mud flux is changing very rapidly due to the migration dynamics of the mud in fracture systems we also observed very short time period cyclic variations with a frequency of several minutes these high frequencies temperature changes could be related to the dynamics of two phase flows gas and mud through the mud volcano conduits

terrestrial methane seeps and mud volcanoes a global perspective of gas origin abstract a global database of gas composition and methane stable isotopes of 143 terrestrial mud volcanoes from 12 countries and 60 seeps independent from mud volcanism from eight countries was compiled and examined in order to provide the first worldwide statistics on the origin of methane seeping at the earth s surface sixteen seep data were coupled with their associated subsurface reservoirs the surface seepage data indicate that at least 76 of the mud volcanoes release thermogenic gas with only 4 biogenic and 20 with mixed character the average 201 data of methane concentration and methane carbon isotope ratios 13 c 1 of mud volcanoes are 90 v v and 46 4 respectively the other types of seeps which are independent from mud volcanism have an average 13 c 1 value that is slightly higher 42 9 gases from mud volcanoes are generally lighter more methane less ethane and propane than their associated reservoir gases suggesting a molecular fractionation during advective fluid migration other types of seeps especially dry seeps maintain the reservoir c 1 c 2 c 3 bernard ratio mud volcanoes behave like a natural refinery and the origin of gas more isotopically enriched than 50 and with c 1 c 2 c 3 500 should be attributed to a thermogenic source rather than partial oxidation of biogenic gas some data that appear biogenic in the bernard diagram can be explained by molecular fractionation of mixed gas consequently the bernard parameter may be misleading when applied to mud volcanoes since it does not always reflect the original gas composition the mechanisms of the molecular advective segregation should be studied quantitatively by specific models and experiments

the arjuno welirang volcanic complex and the connected lusi system geochemical evidences abstract for the first time we present the geochemical characterization of fluids emitted from the arjuno welirang volcanic complex and compare the results with those obtained sampling the neighboring spectacular lusi eruption site java island indonesia the isotopic composition of the hydrothermal and cold waters from the welirang volcanic complex indicate a meteoric origin for these springs with values ranging from 65 to 50 and 6 to 1 vs v smow respectively for d and 18 o the water erupted from the lusi site showed clustered higher d and 18 o isotopic values ranging around 6 and 10 vs v smow respectively we ascribe these results to mixing between hydrothermal fluids meteoric water saline formation fluids and water released during clay mineral illitization ultimately altered by additional evaporation processes the chemical and isotopic composition of fluids emitted from fumaroles and hydrothermal springs of the welirang volcano showed a clear magmatic signature where a co 2 dominated gas reveals 13 c co2 ranging between 5 9 and 2 4 and helium isotope with r ra 7 3 these values are very close to those measured at lusi site r ra 7 that also have high co 2 ch 4 ratio 1 7 2 2 supporting the high contribution of magmatic gases moreover a great contribution of andesitic water has been recognized in the water vapour emitted from the summit fumaroles converging geochemical data indicate that the plumbing system of the lusi eruption site is connected at depth with the arjuno welirang volcanic complex these data support a scenario where hydrothermal fluids from the volcanic system migrated in the sedimentary basin triggering metamorphic reactions in the organic rich sediments that ultimately resulted in a venting system at the surface after eleven years of incessant activity this venting system remains constantly fed by the fluids from the volcanic complex and became world known as lusi the largest ongoing clastic geysering system on earth

significance of mud volcanism 1 mud volcanism and diapirism have puzzled geoscientists for 2 centuries they have been described onshore and offshore in many places on earth and although they occur in various tectonic settings the majority of the features known to date are located in compressional tectonic scenarios this paper summarizes the main thrusts in mud volcano research as well as the various regions in which mud volcanism has been described mud volcanoes show variable geometry up to tens of kilometers in diameter and several hundred meters in height and a great diversity regarding the origin of the fluid and solid phases gas predominantly methane water and mud may be mobilized at subbottom depth of only a few meters but in places can originate from several kilometers depth with minor crustal or mantle input the possible contribution of mud extrusion to global budgets both from quiescent fluid emission and from the extrusive processes themselves is important in regions where mud volcanoes are abundant such as the collision zones between africa and eurasia fluid flux through mud extrusion exceeds the compaction driven pore fluid expulsion of the accretionary wedge also quiescent degassing of mud volcanoes may contribute significantly to volatile budgets and hence to greenhouse climate

triggering of the lusi mud eruption earthquake versus drilling initiation abstractthe lusi mud volcano in east java has erupted unabated for almost 2 yr ooding an area of 7 km 2 and displacing more than 25 000 people despite its disastrous impact the mechanism for triggering the lusi eruption remains highly controversial two distinct mechanisms have been proposed one hypothesis suggests that the eruption was triggered by the m w 6 3 earth quake that struck yogyakarta 250 km from lusi two days before the eruption however an examination of static and dynamic stress changes and stress transfer mechanisms indicates that the yogyakarta earthquake was at least an order of magnitude too small to reactivate faults and open uid ow pathways under lusi an alternate theory suggests that lusi was triggered by a blowout following drilling problems in the nearby banjar panji 1 well blowouts result from an inability to control pore uid intakes into the borehole and typically occur when the drilling win dow fracture pressure minus pore pressure is approximately zero and when there is insuf cient protective casing of the well bore pore and fracture pressure data from banjar panji 1 indicate that the well had a narrow drilling window of only 0 2 3 mpa furthermore two planned casing points were skipped during drilling resulting in 1742 m of unprotected borehole the combina tion of hazardously narrow drilling window and long uncased borehole would have made drill ing problems in banjar panji 1 dif cult to control placing the well at high risk of blowing out furthermore well bore pressures following drilling problems in banjar panji 1 reached magni tudes in excess of the fracture pressure and thus were suf cient to create uid ow pathways in the subsurface therefore we suggest that no viable method is known by which the yogyakarta earthquake could have triggered the mud ow and that a blowout in the banjar panji 1 well was the most likely mechanism for triggering the lusi eruption keywords

methane emission from the mud volcanoes of sicily italy 1 mud volcanoes represent the largest expression of natural methane release into the atmosphere however the gas flux has never been investigated in detail methane output from vents and diffuse soil degassing is herewith reported for the first time measurements were carried out at 5 mud volcano fields around sicily italy each mud volcano is characterized by tens of vents and bubbling pools in the quiescent phase methane emission from single vents ranges between 0 01 and 6 8 kg day diffuse soil leakage around the vents is in the order of 102 104 mg m 2 d 1 an exceptional flux of 106 mg m 2 d 1 was recorded close to an everlasting fire soil ch4 flux is positive even at large distances from the mud volcano fields suggesting a diffuse microseepage over wider areas a total of at least 400 tons ch4 per year can be estimated over the area investigated alone 1 5 km2

a geochemical study on mud volcanoes in the junggar basin china abstract a comprehensive study was performed to characterize for the first time the mud water and gases released from onshore mud volcanoes located in the southern margin of the junggar basin northwestern china chemical compositions of mud along with the geology of the basin suggest that a source of the mud is mesozoic or cenozoic shale oxygen and h isotope compositions of the released water suggest a local meteoric origin combined with the positive eu anomalies of the water a large 18 o shift of the water suggests extensive interaction with rocks gases discharged from the mud volcanoes are predominantly thermogenic hydrocarbons and the high 13 c values 20 vpdb for co 2 gases and dissolved carbonate in muddy water suggest secondary methanogenesis with co 2 reduction after oil biodegradation the enrichments of eu and 18 o in water and the low thermal gradient of the area suggest that the water rock interactions possibly occur deeper than 3670 200 m on the other hand considering the relationship to the petroleum reservoir around the mud volcanoes the depth of the gases can be derived from about 3600 m a depth that is greater than that generally estimated for reservoirs whose gas is characterized by 13 c enriched co 2 oil biodegradation with co 2 reduction likely occurs at a shallower depth along the seepage system of the mud volcano the results contribute to the worldwide data set of gas genesis in mud volcanoes moreover they further support the concept that most terrestrial mud volcanoes release thermogenic gas produced in very deep sediments and may be early indicators of oil biodegradation an important problem in the petroleum industry

origin of carbon in fumarolic gas from island arcs abstract we have measured 3 he 4 he ratios 13c values and co 2 3 he ratios of fumaroles and hot spring gases in three volcanic areas in japan the 3 he 4 he ratios 13c values and co 2 3 he ratios vary from 02 05 ratm 9 7 to 2 7 and from 7 74 109 to 1 18 1011 respectively based on these data and those in the literature we present the first quantitative estimates of the upper mantle sediment and limestone including slab components in co2 of volcanic and hydrothermal fluids from subduction zones taking compiled c isotopic data of limestone and organic sediment assuming that the co 2 3 he ratio and 13c value of mid ocean ridge basalt morb are representative of the upper mantle component and that later isotopic and elemental fractionations are minimal it is possible to deconvole each fraction of c on the basis of simple mixing equations up to 20 of the carbon in high temperature volcanic gases in subduction zones is derived from a morb type source while the major fraction of the gases is attributable to co2 produced by decarbonation of subducted marine limestone and slab carbonate

earthquake induced thermal anomalies at active volcanoes answering the question whether a regional earthquake can trigger or enhance volcanic activity requires a systematic measure of volcanic activity one such measure is heat fl ux the availability since a d 2000 of a satellite derived heat fl ux inventory for global volcanism allows us to explore how earthquakes and volcanic activity may be linked examination of 7 yr of global volcanic heat fl ux data reveals 37 volcanic responses to regional earthquakes each response is expressed by an increase in heat fl ux within 1 21 days of the triggering earthquake whether a volcano responds depends on earthquake magnitude distance to the epicenter and orientation of the earthquake focal mechanism in respect to the volcano the focal mechanism has to align with the responding system of the 7 global major increases of seismic energy during 2000 2006 4 were followed by a global volcanic heat fl ux increase the largest response involved a 300 increase and followed the largest earthquake in the period the 2004 sumatraandaman indonesia earthquake moment magnitude m w 9 3

influence of bank vegetation on channel morphology in rural and urban watersheds stream bank vegetation significantly influences the morphology of streams in the piedmont region of the united states we surveyed the morphology of 26 paired stream reaches in southeastern pennsylvania northern maryland and delaware one member of each pair has a forested riparian zone whereas the other has a riparian zone composed pri marily of grass the paired reaches are nearly contiguous so all significant channel forming variables except riparian vegetation are held constant the extent of urban development of the watersheds upstream of the paired reaches also varies considerably allowing us to determine the combined influence of riparian vegetation and urbanization on channel morphology statistical analyses indicate that 1 channels with forested riparian zones are wider than channels with nonforested riparian zones 2 channels in urbanized watersheds are wider than channels in nonurbanized watersheds and 3 the effect of riparian vegetation is independent of the level of urbanization

variations in the chemical and stable isotope composition of carbon and sulfur species during organic rich sediment alteration an experimental and theoretical study of hydrothermal activity at guaymas basin gulf of california organic rich diatomaceous ooze was reacted with seawater and a na ca k cl fluid of seawater chlorinity at 325 400 c 400 500 bars and fluid sediment mass ratios of 1 56 2 35 to constrain factors regulating the abundance and stable isotope composition of c and s species during hydrothermal alteration of sediment from guaymas basin gulf of california alteration of inorganic and organic sedimentary components resulted in extensive exchange reactions the release of abundant h2s co2 ch4 and corganic to solution and recrystallization of the sediment to an assemblage containing albitic plagioclase quartz pyrrhotite and calcite the 34scdt values of dissolved h2s varied from 10 9 to 4 3 during seawater sediment interaction at 325 and 400 c and from 16 5 to 9 0 during na ca k cl fluid sediment interaction at 325 and 375 c in the absence of seawater so4 h2s is derived from both the transformation of pyrite to pyrrhotite and s released during the degradation of organic matter in the presence of seawater so4 reduction of so4 contributes directly to h2s production sedimentary organic matter acts as the reducing agent during pyrite and so4 reduction requisite acidity for the reduction of so4 is provided by mg fixation during early stage sediment alteration and by albite and calcite formation in mg free solutions organically derived ch4 was characterized by 13cpdb values ranging between 20 8 and 23 1 whereas 13cpdb values for dissolved corganic ranged between 14 8 and 17 7 mass balance calculations indicate that 13c values for organically derived co2 were 14 8 residual solid sedimentary organic c showed small 0 7 depletions in 13c relative to the starting sediment the experimental results are consistent with the isotopic and chemical composition of natural hydrothermal fluids and minerals at guaymas basin and permit us to better constrain sources and sinks for c and s species in subseafloor hydrothermal systems at sediment covered spreading centers our data show that the sulfur isotope composition of hydrothermal sulfide minerals in guaymas basin can be explained by derivation of s from diagenetic sulfide and seawater sulfate basaltic s may also contribute to hydrothermal sulfide precipitates but is not required to explain their isotopic composition estimates of seawater sediment mass ratios based on sulfur isotopic composition of sulfide minerals and the abundance of dissolved nh3 in vent fluids range from 3 29 during hydrothermal circulation sources of c in guaymas basin hydrothermal fluids include thermal degradation of organic matter bacteriogenic methane production and dissolution of diagenetic carbonate

deep and shallow sources for the lusi mud eruption revealed by surface deformation the lusi mud eruption in east java indonesia began in may 2006 and continues to the present previous analyses of surface deformation data suggested an exponential decay of the pressure in the mud source but did not constrain the location geometry and evolution of the possible source s of the erupting mud and fluids to map the surface deformation we employ multitemporal interferometric synthetic aperture radar and analyze a well populated l band data set acquired by the advanced land observing satellite alos between may 2006 and april 2011 we then apply a time dependent inverse modeling scheme volume changes occur in two regions beneath lusi at 0 3 2 0 km and 3 5 4 75 km depth the cumulative volume change within the shallow source is 2 3 times larger than that of the deep source the observation and model suggest that a shallow source plays a key role by supplying the erupting mud but that additional fluids do ascend from depths 4 km on eruptive timescales

abiotic methane flux from the chimaera seep and tekirova ophiolites turkey understanding gas exhalation from low temperature serpentinization and implications for mars abstract the emission of abiotic methane ch 4 into the atmosphere from low temperature serpentinization in ophiolitic rocks is documented to date only in four countries the philippines oman new zealand and turkey serpentinization produces large amounts of hydrogen h 2 which in theory may react with co 2 or co to form hydrocarbons fischer tropsch type synthesis ftt similar mechanisms have been invoked to explain the ch 4 detected on mars so that understanding flux and exhalation modality of ophiolitic gas on earth may contribute to decipher the potential degassing on mars this work reports the first direct measurements of gas ch 4 co 2 flux ever done on onshore ophiolites with present day serpentinization we investigated the tekirova ophiolites at cirali in turkey hosting the chimaera seep a system of gas vents issuing from fractures in a 5000 m 2 wide ophiolite outcrop at this site at least 150 190 t of ch 4 is annually released into the atmosphere the molecular and isotopic compositions of c 1 c 5 alkanes co 2 and n 2 combined with source rock maturity data and thermogenic gas formation modelling suggested a dominant abiotic component 80 90 mixed with thermogenic gas abiotic h 2 rich gas is likely formed at temperatures below 50 c suggested by the low deuterium hydrogen isotopic ratio of h 2 d h2 720 consistent with the low geothermal gradient of the area abiotic gas synthesis must be very fast and effective in continuously producing an amount of gas equivalent to the long lasting 2 millennia emission of 100 t ch 4 yr 1 otherwise pressurised gas accumulation must exist over the same ophiolitic formation 3 km away from chimaera we detected an invisible microseepage of abiotic ch 4 with fluxes from 0 07 to 1 g m 2 d 1 on mars similar fluxes could be able to sustain the ch 4 plume apparently recognised in the northern summer 2003 10 4 or 10 5 t yr 1 over the wide olivine bedrock and outcrops of hydrated silicates in the syrtis major and nili fossae just one seep like chimaera or more realistically a weak spatially sporadic microseepage would be sufficient to maintain the atmospheric ch 4 level on mars

effects of land use change on channel morphology in northeastern puerto rico between 1830 and 1950 much of northeastern puerto rico was cleared for agriculture runoff increased by 50 and sediment supply to the river channels increased by more than an order of magnitude much of the land clearance extended to steep valley slopes resulting in widespread gullying and landslides and a large load of coarse sediments delivered to the stream channels a shift from agriculture to industrial and residential land uses over the past 50 yr has maintained the elevated runoff while sediment supply has decreased allowing the rivers to begin removing coarse sediment stored within their channels the size abundance and stratigraphic elevation of in channel gravel bar deposits increases channel depth decreases and the frequency of overbank flooding increases downstream along these channels this is presumed to be a transient state and continued transport will lead to degradation of the bed in downstream sections as the channel adjusts to the modern supply of water and sediment a downstream decrease in channel size is contrary to the expected geometry of self adjusted channels but is consistent with the presence of partially evacuated sediment remaining from the earlier agricultural period reverse downstream decreasing channel morphology is not often cited in the literature although consistent observations are available from areas with similar land use history identification of reverse channel morphology along individual watercourses may be obscured in multiwatershed compilations in which other factors produce a consistent but scattered downstream trend identification of reverse channel morphology along individual streams in areas with similar land use history would be useful for identifying channel disequilibrium and anticipating future channel adjustments

origin and age of carbonate clasts from the lusi eruption java indonesia abstract deep stratigraphic constrains below the indonesian lusi mud eruption are currently lacking due to the absence of deep wells and good quality seismic data a collection of carbonate clasts has been sampled from the lusi site active since its birth in 2006 these specimens are part of a large variety of lithotypes erupted from the main crater the carbonates analysed comprise scleractinian coral and bivalve shell fragments probably shallow water in origin and clasts consisting of planktonic foraminifera bearing mudstone from pelagic deposits selected rocks were analysed using planktonic foraminifera and 87sr 86sr dating with the aim to constrain their age and to improve the understanding of the so far unknown sequence of limestone deposits inferred at this site based on biostratigraphy using planktonic foraminifera one group of samples reveal to belong to the planktonic foraminifera zone m5b with an age comprised between 16 29 and 15 10 ma miocene latest burdighalian to langhian the sr isotope based ages of clasts analysed for 87sr 86sr cover a larger time window spanning from pliocene zanclean and piacenzian miocene messinian down to eocene priabonian the pliocene and messinian ages are unreasonably young from what is known of the local geology and one sample provided an 87sr 86sr age that is 8 my younger compared to that obtained from the planktonic foraminifera assemblage occurring in that sample the discrepancy suggests that this and the other unduly young samples have possibly been contaminated by geological materials with radiogenic sr isotope composition the minimum age of 37 18 ma obtained by 87sr 86sr from a well preserved oyster shell indicates that some of the clasts can be attributed to the deep seated ngimbang formation the dating has been combined with the interpretation of seismic profiles to investigate the stratigraphy of inferred carbonates below lusi and the prg 1 well located some kilometres to the north east prg 1 borehole data are also integrated and discussed in this study the obtained results reveal multiple implications a the tuban and kujung formations are overlapping at lusi site b the lusi feeder conduit brecciated and mobilized to the surface carbonate lithologies buried as deep as possibly 3 8 km as well as even older and deeper seated lithotypes from the ngimbang formation c since the deeper carbonate samples erupted in 2006 belong to the typically not overpressured kujung formation an additional overpressure generated from deeper units ngimbang formation would be required to force these fragments to surface

fluvial responses to land use changes and climatic variations within the drury creek watershed southern illinois abstract fluvial responses to climatic variation and anglo american settlement were documented for the drury creek watershed southern illinois by examining stratigraphic geomorphic climatic and historical data regional analyses of long term precipitation records document a period of decreasing mean annual precipitation from 1904 to about 1945 and an increasing trend in annual precipitation from 1952 to the present the period between 1945 and 1951 experienced a large number of intense storms that resulted in high annual precipitation totals statistical relationships illustrate that changes in precipitation totals are transferred to the hydrologic system as fluctuations in stream discharge historical records of southern illinois show that a maximum period of settlement and deforestation occurred between the 1860s and 1920s this era ended in the 1940s when large tracts of land were revegetated in an attempt to curtail erosion which had caused extensive upland degradation in response to hillslope erosion at least two meters of fine grained sediments were deposited on valley floors average sedimentation rates determined using decdrochronologic techniques are estimated to be 2 11 cm yr for the period between 1890 and 1988 rates that are 1 to 2 orders of magnitude greater than pre settlement values calculated for other areas of the midwest however botanical data suggest that aggradation was episodic possibly occurring during three periods characterized by greater annual precipitation since the 1940s sedimentation rates have declined reduced rates of sedimentation are related to an episode of channel entrenchment that reduced overbank flooding entrenchment coincided with a period of 1 reduced sediment yields associated with watershed revegetation and the introduction of soil conservation practices and 2 intense storm activity that resulted in long periods of high discharge as a result of channel incision and hillslope erosion newly exposed bedrock in upstream areas currently provides a source of gravel load to the channels the distribution of coarse bedload material along tributary streams combined with downstream decreases in width depth ratios and tractive force estimates suggest that channels in the drury creek watershed are slowly adjusting their configuration to transport coarse bedload material the fluvial response to the increased influx of coarse sediment began more than 45 years ago and continues today

framing realistic river rehabilitation targets in light of altered sediment supply and transport relationships lessons from east gippsland australia since european settlement the cann river in east gippsland victoria has experienced a 700 increase in channel capacity a 150 fold increase in the rate of lateral channel migration a 45 fold increase in bankfull discharge and a 860 fold increase in annual sediment load over the last century and primarily the last 40 years channel incision has removed the equivalent of around 1500 years of floodplain deposition a numerical floodplain evolution model is presented which suggests that under a best case scenario infilling the incised channel trench will take 31 000 years and this is predicated on the full recovery of the immediate riparian vegetation and the in channel loading of woody debris the asymmetry in the recovery time following rapid channel change compared with the original deposition of the material is explained by a combination of the sediment starved character of the catchment and the altered hydraulic conditions within the channel principally associated with the role of woody debris these factors have major implications for geomorphic recovery potential constraining what can be realistically achieved in river rehabilitation

a new hydrothermal scenario for the 2006 lusi eruption indonesia insights from gas geochemistry abstract the 29th of may 2006 gas and mud eruptions suddenly appeared along the watukosek fault in the north east of java indonesia within a few weeks several villages were submerged by boiling mud the most prominent eruption site was named lusi to date november 2011 lusi is still active and a 7 km2 area is covered by the burst mud breccia the mechanisms responsible for this devastating eruption remain elusive while there is consensus about the origin of the erupted mud the source of water is uncertain the origin of the gas is unknown and the trigger of the eruption is still debated in order to shed light on these unknowns we acquired a wide set of data of molecular and isotopic composition of gas sampled in several lusi vents in the surrounding mud volcanoes in the closest natural gas field wunut and in the hydrothermal vents at the neighbouring volcanic complex in the period 2006 2011 the boiling fluids erupted in the crater zone are apparently co2 dominated while colder ch4 dominated and c2 c3 bearing fluids are identified at several sites around the crater zone gas genetic diagrams maturity plots and gas generation modelling suggest that the hydrocarbons are thermogenic 13c1 up to 35 13c2 up to 20 deriving from marine kerogen with maturity of at least 1 5 ro for instance in the 4400 m deep ngimbang source rocks co2 released from the crater and surrounding seeps is also thermogenic 13c from 15 to 24 related to kerogen decarboxylation or thermal ch4 oxidation in deep rocks although three vents just outside the crater showed an apparent inorganic signature 7 5 4000 m magmatic intrusions and hydrothermal fluids responsible for the enhanced heat that altered source rocks and or gas reservoirs the neighbouring magmatic arjuno complex and its fluid pressure system combined with high seismic activity could have played a key role in the lusi genesis and evolution within this new model framework lusi is better understood as a sediment hosted hydrothermal system rather than a mud volcano

evidence of subsurface anaerobic biodegradation of hydrocarbons and potential secondary methanogenesis in terrestrial mud volcanoes abstract the assessment of gas origin in mud volcanoes and related petroleum systems must consider post genetic processes which may alter the original molecular and isotopic composition of reservoir gas beyond eventual molecular and isotopic fractionation due to gas migration and microbial oxidation investigated in previous studies we now demonstrate that mud volcanoes can show signals of anaerobic biodegradation of natural gas and oil in the subsurface a large set of gas geochemical data from more than 150 terrestrial mud volcanoes worldwide has been examined due to the very low amount of c 2 in mud volcanoes isotopic ratios of ethane propane and butane generally the best tracers of anaerobic biodegradation are only available in a few cases however it is observed that 13 c enriched propane is always associated with positive 13 c co2 values which are known indicators of secondary methanogenesis following anaerobic biodegradation of petroleum data from carbon isotopic ratio of co 2 are available for 134 onshore mud volcanoes from 9 countries azerbaijan georgia ukraine russia turkmenistan trinidad italy japan and taiwan exactly 50 of mud volcanoes all releasing thermogenic or mixed methane show at least one sample with 13 c co2 5 pdb thermogenic ch 4 associated with positive carbon isotopic ratio of co 2 generally maintains its 13 c enriched signature which is therefore not perturbed by the lighter secondary microbial gas there is however high variability in the 13 c co2 values within the same mud volcanoes so that positive 13 c co2 values can be found in some vents and not in others or not continuously in the same vent this can be due to high sensitivity of 13 c co2 to gas water rock interactions or to the presence of differently biodegraded seepage systems in the same mud volcano however finding a positive 13 c co2 value should be considered highly indicative of anaerobic biodegradation and further analyses should be made especially if mud volcanoes are to be used as pathfinders of the conditions indicative of subsurface hydrocarbon accumulations in unexplored areas

enhanced hydrothermal processes at the new born lusi eruptive system indonesia abstract little is known about the processes taking place in new born hydrothermal systems we investigate the eruptive activity of lusi a sediment hosted hydrothermal system active since 2006 in east java indonesia we show that superimposed on the regular geysering activity lusi features periods of enhanced hydrothermal processes during which boiling mud breccia is violently discharged from the eruptive vents this results in sudden flooding lasting from several minutes to several hours and featuring almost instantaneous temperature peaks i e from 35 c to more than 65 c in less than 2 min such activity here named hydrothermal waves is marked by high frequency seismic radiations and is distinguished by sharp peaks of ch4 and co2 concentrations in the erupted fluids this suggests fluids upwelling from at least tents of meters below the near surface the injection into the shallow plumbing system of ch4 and co2 rich batches of fluids may promote instabilities in the mud breccia column leading to the hydrothermal waves our findings provide key insights into the deep charging dynamics of a new born hydrothermal system and highlight the effects imposed by subtle variations in fluid chemistry changes at depth

discharge predictions of a rainfall driven theoretical hydrograph compared to common models and observed data 1 a theoretical hydrograph based on darcy s law and the diffusion equation has been extended into a predictive model for the discharge of diffuse springs and small rivers from a detailed rainfall record using only a single free parameter the basin time constant b the model accurately predicts the flow variations of natural hydrographs including the magnitude and timing of peak flow total flow volume inflection points and recession rate all as a function of effective rainfall amounts basin area and the time constant b predicted hydrographs for a sharp storm event in an unimpounded basin are compared to results for two common transfer functions and our more parsimonious model is statistically superior modeling of a long term record in proximal basins illustrates the effect of variations in b potential applications of the model include flood prediction comparative studies of basin response in a regional context and estimation of actual evapotranspiration

carbon release from submarine seeps at the costa rica fore arc implications for the volatile cycle at the central america convergent margin 1 we report total dissolved inorganic carbon dic abundances and isotope ratios as well as helium isotope ratios 3he 4he of cold seep fluids sampled at the costa rica fore arc in order to evaluate the extent of carbon loss from the submarine segment of the central america convergent margin seep fluids were collected over a 12 month period at mound 11 mound 12 and jaco scar using copper tubing attached to submarine flux meters operating in continuous pumping mode the fluids show minimum 3he 4he ratios of 1 3 ra where ra is air 3he 4he consistent with a small but discernable contribution of mantle derived helium at mound 11 13c co2 values between 23 9 and 11 6 indicate that dic is predominantly derived from deep methanogenesis and is carried to the surface by fluids derived from sediments of the subducting slab in contrast at mound 12 most of the ascending dissolved methane is oxidized due to lower flow rates giving extremely low 13c co2 values ranging from 68 2 to 60 3 we estimate that the carbon flux co2 plus methane through submarine fluid venting at the outer fore arc is 8 0 105 g c km 1 yr 1 which is virtually negligible compared to the total sedimentary carbon input to the margin and the output at the volcanic front unless there is a significant but hitherto unidentified carbon flux at the inner fore arc the implication is that most of the carbon being subducted in costa rica must be transferred to the deeper mantle i e beyond the depth of arc magma generation

release of methane from a volcanic basin as a mechanism for initial eocene global warming a 200 000 yr interval of extreme global warming marked the start of the eocene epoch about 55 million years ago negative carbon and oxygen isotope excursions in marine and terrestrial sediments show that this event was linked to a massive and rapid approximately 10 000 yr input of isotopically depleted carbon it has been suggested previously that extensive melting of gas hydrates buried in marine sediments may represent the carbon source and has caused the global climate change large scale hydrate melting however requires a hitherto unknown triggering mechanism here we present evidence for the presence of thousands of hydrothermal vent complexes identified on seismic reflection profiles from the voring and more basins in the norwegian sea we propose that intrusion of voluminous mantle derived melts in carbon rich sedimentary strata in the northeast atlantic may have caused an explosive release of methane transported to the ocean or atmosphere through the vent complexes close to the palaeocene eocene boundary similar volcanic and metamorphic processes may explain climate events associated with other large igneous provinces such as the siberian traps approximately 250 million years ago and the karoo igneous province approximately 183 million years ago

effects of urbanization on watershed hydrology the scaling of discharge with drainage area this study examines the effects of impervious surfaces within urbanized land on the scaling of river discharge with drainage area discharge in a river channel grows as drainage basin area increases following the general equation q ka c where q is river discharge k is a measure of river base flow a is upstream drainage area and c is the scaling power dependency land use is a critical variable in the examination of river discharge discharge has significant geologic and ecologic influences on fluvial systems discharge is assumed to scale linearly or nearly linearly with drainage area c 1 but in spite of its widespread application the relationship has not been explicitly tested with respect to urbanization here we show that in small urban settings the scaling is nonlinear for peak flows it is proposed that effective water loading occurs through a combination of increased runoff and an increase in the rate of transport to the rivers these higher discharges in urban rivers have the potential to increase erosion degrade aquatic habitats and significantly alter channel forms

lusi mud eruption triggered by geometric focusing of seismic waves the lusi mud eruption in indonesia has been ongoing since 2006 numerical simulations show that a parabolic shaped layer in the rock surrounding the site of the lusi eruption could have amplified and focussed incoming seismic energy from an earthquake which then triggered the mud eruption

modelling of gas generation following emplacement of an igneous sill below lusi east java indonesia highlights we have tested a hypothesis where a sill intrusion is present at depth near lusi we have calculated the co2 generation following the emplacing a 150 m sill in an organic rich sequence at 4 5 km this scenario may provide the co2 currently emitted from lusi and are consistent with geological information abstract the lusi mud eruption started in 2006 and is located near the arjuno welirang volcanic complex in northeastern java lusi is characterized by the eruption of aqueous vapor co2 and ch4 in addition to mud breccia and boiling water however the ultimate driving force for the eruption remains unclear here we investigate if lusi could have been driven by the heat released from a deep seated igneous sill originating from the neighboring volcanic arc we have used a 1d thermal model to calculate the production of co2 from thermally matured organic matter in the contact aureole of a hypothetical 150 m thick sill the sill is tentatively emplaced at 1100 c at 4 5 km depth within the organic rich eocene ngimbang formation the carbon gas produced from the thermal perturbation reaches a peak of 1357 kg m2 y co2 equivalents shortly after sill emplacement stressing the efficiency of organic matter transformation in contact aureoles our simulations show that during the first 1000 years after emplacement 53 5 ton co2 m2 is produced in the contact aureole when scaled to a sill size of 150 m 25 km2 i e a sill volume of 3 75 km3 the aureole has the potential to generate a total of 1350 mt co2 during the first 1000 years with a peak generation of about 34 mt co2 y we conclude that contact metamorphism in our hypothetical geological scenario generates co2 in the gigaton range and represents a plausible source for the lusi gas

seismicity at lusi and the adjacent volcanic complex java indonesia abstract we study the local seismicity in east java around the arjuno welirang volcanic complex that is connected via the watukosek fault system to the spectacular lusi eruption site lusi is a sediment hosted hydrothermal system which has been erupting since 2006 it is fed by both mantellic and hydrothermal fluids rising and mixing with the thermogenic gases and other fluids from shallower sedimentary formations during a period of 24 months we observe 156 micro seismic earthquakes with local magnitudes ranging from m l 0 5 to m l 1 9 within our network the events predominantly nucleate at depths of 8 13 km below the arjuno welirang volcanic complex despite the geological evidence of active tectonic deformation and faulting observed at the surface practically no seismicity is observed in the sedimentary basin hosting lusi although we cannot entirely rule out artifacts due to an increased detection threshold in the sedimentary basin the deficit in significant seismicity suggests aseismic deformation beneath lusi due to the large amount of fluids that may lubricate the fault system an analysis of focal mechanisms of nine selected events around the arjuno welirang volcanic complex indicates predominantly strike slip faulting activity in the region sw of lusi this type of activity is consistent with observable features such as fault escarpment river deviation and railroad deformation suggesting that the watukosek fault system extends from the volcanic complex towards the ne of java our results point out that the tectonic deformation of the region is characterized by a segmented fault system being part of a broader damage zone rather than localized along a distinct fault plane

genetic characterization of natural gases natural gases can be characterized genetically using four properties c2 concentration carbon and hydrogen isotope variations in methane and carbon isotope variation in ethane three diagrams for genetic characterization of gases have been designed in which the carbon isotopic composition of methane is correlated with the other parameters in these diagrams compositional fields have been defined for primary gases biogenic thermogenic associated and thermogenic nonassociated and for gases which result from mixing of these gases these fields are strictly empirical and comprise compositional variations found in about 500 natural gases the isotopic and compositional variations in natural gases can be described in terms of 1 processes during formation of the gases such as bacterial fermentation or maturation of organic matter and 2 processes during secondary migration mixing of primary gases is an important and common process migration of gases predominantly affects the c2 concentration whereas the isotopic properties of gaseous hydrocarbons primarily remain unchanged allowing an assessment of the origin of migrated gases and properties of their source rocks the formation of gas from humic organic matter and coals is not yet clear from published data the diagrams use data from various basins and areas interstitial gases from the gulf of california are entirely of bacterial origin traces of thermogenic gases are formed only in the vicinity of dolerite sills gases in the south german molasse basin and in the vienna basin are of bacterial mixed and thermogenic origins data from the north italian po basin provide examples for genetic characterization of migrated gases

the formation of giant clastic extrusions at the end of the messinian salinity crisis abstract this paper documents the discovery of five multi km scale lensoid bodies that directly overlie the upper surface of the thick 1 km messinian evaporite sequence they were identified through the analysis of 3d seismic data from the western nile cone the convergence of the upper and lower bounding reflections of these lensoid bodies their external and internal reflection configuration the positive depositional relief at their upper surface and the stratal relationship with underlying and overlying deposits supports the interpretation that these are giant clastic extrusions the interpretations combined with the stratal position of these clastic extrusions demonstrate a prior unsuspected link between periods of major environment change and basin hydrodynamics on a plate scale all five lensoid bodies were extruded onto a single seismically resolvable marker horizon correlatable with the end of the messinian salinity crisis horizon m it is argued that the source of these clastic extrusions is pre messinian in origin which implies massive sediment remobilisation at depth in the pre evaporitic succession and intrusion through the thick evaporite layer we propose that the scale and timing of this dramatic event was primed and triggered by near lithostatic overpressure in the pre evaporitic sediments generated through 1 their rapid burial and loading during the messinian salinity crisis and 2 catastrophic re flooding during its immediate aftermath the largest of these clastic extrusions has a volume of over c 116 km3 making it amongst the largest extruded sedimentary bodies described on earth the findings extend the understanding of the upper scale of other analogous clastic extrusions such as mud volcanoes and sediment hosted hydrothermal systems following the 2006 eruption of the lusi sediment hosted hydrothermal system in indonesia an understanding of the upper scale limit of clastic extrusions has even greater societal relevance in order to increase awareness of the risk posed by the potential size and longevity of future giant clastic extrusions

deep hydrothermal activity driving the lusi mud eruption abstract the lusi mud eruption in east java continues unabated after more than a decade of activity as a pulsating geyser system bursting mud clasts water and gas the origin of the fluids and their properties at depth are not well constrained thus hampering our understanding and modelling of the system previous geochemical and geophysical studies show that lusi is a sediment hosted hydrothermal system with two sources of mud at depths between 0 3 2 km and another between 3 5 4 75 km here we present results of mineral thermometry using raman spectroscopy and chlorite composition on clasts erupted at lusi the results show that some of these specimens originate from the two main fluid sources and at depths consistent with the geochemical and geophysical interpretation two main clast lithotypes erupt at lusi the first lithotype is a light grey shale returned to the surface from the upper kalibeng formation the primary mud source and equilibrated at temperatures below 200 c the second lithotype is a black shale whose source is the ngimbang formation at 3800 m depth two distinct temperature clusters are recorded in these black shales one at 179 17 c consistent with the temperature estimate at 3800 m depth with the pre eruption geothermal gradient while younger minerals in the same specimen recorded substantial anomalous heating at 250 c these high temperatures indicate interaction with a heat source associated with the eruption through mixing with hydrothermal fluids this temperature jump suggests rapid heating at 4000 m depth consistent with a scenario of a magmatic intrusion and hydrothermal fluids circulation this rapid and significant temperature increase would initiate devolatilisation reactions of hydrous minerals within the deep sedimentary package and generate substantial highly overpressured fluids at depths significantly below the main source of erupted mud we infer that reactive and thermal pressurisation led to a deep and metastable system susceptible to e g seismic activity ultimately opening fluid pathways towards the surface along the watukosek fault system the two temperatures clusters recorded in the clasts show that conductive heat flow was the dominant heat transport prior to the eruption while the system is now driven by large scale convection and advective heat transport the lusi eruption occurred in a highly populated area forcing the evacuation of several tens of thousands of people this system appears unstoppable and poses a real and present hazard for the settlements still surrounding the eruption site continuous research is necessary to understand this spectacular phenomenon both for its important scientific relevance and the societal impact of this natural disaster

comparing gravel bed rivers in paired urban and rural catchments of southeastern pennsylvania surveys in eight paired urban and rural watersheds illustrate how urbanization changes fluvial morphology and processes our data also provide quantitative criteria for evaluating streamrestoration projects in urban areas bankfull depth reach averaged bed slope and median grain size are similar in urban and rural watersheds the median width of urban channels is 26 larger than the median width of rural channels the median sinuosity is 8 lower in urban channels and pools are 31 shallower the median composite manning s n based on median grain diameter pool depth and channel sinuosity is 10 lower in urban streams while the median bankfull discharge per unit drainage basin area is 131 higher in urban channels histograms of bed sediment size distributions in urban channels lack a secondary mode in the size range 2 64 mm characteristic of rural channels indicating that these sizes tend to be selectively removed from urban channels however bankfull shields stresses in urban and rural channels exceed typical threshold values at most sites indicating significant bedload transport at bankfull stage apparently increased peak discharges caused by decades of urbanization have not removed all the transportable sediment from these urban stream channels we speculate that the supply of sediment to urban channels from hillslope processes and channel erosion remains significant even though much of the upland surfaces of these urban catchments are covered with nonerodible impervious surfaces

regional earthquake as a trigger for enhanced volcanic activity evidence from modis thermal data 1 the magnitude 6 4 earthquake that occurred in java on 26 may 2006 provided us with data capable of revealing an immediate eruptive response at two javanese volcanoes merapi and semeru the availability of pre processed thermal data for volcanic hot spots detected by the moderate resolution imaging spectrometer modis and provided on http hotspot higp hawaii edu allowed us to produce heat and volume flux time series for these two erupting volcanoes covering a 35 day period spanning the earthquake our results revealed a coupled response by the volcanoes to the earthquake both experiencing increases in heat and volume flux beginning 3 days after the earthquake with the response lasting 9 days the response was felt at both volcanoes as a factor of two to three increase in the rate of volumetric output after which output returned to the pre response rates this implies that the earthquake triggered enhanced output at two erupting volcanoes 50 and 300 km distant from the earthquake epicenter and separated from each other by 260 km

probabilistic longevity estimate for the lusi mud volcano east java abstract a new method for estimating the duration of a mud volcano eruption is applied to the lusi mud volcano in east java the estimate is based upon carbonates at depths in the range 2500 3500 m being the water source with an estimated area of 100 600 km 2 thickness of 0 2 1 0 km porosity of 0 15 0 25 an initial pressure between 13 9 and 17 6 mpa and a separate shallower source of mud c 1200 1800 m depth the resulting 50 percentile for the time it takes for flow to decline to 1 is 26 years by analogy with natural mud volcanoes it can be expected to continue to flow at lower rates for thousands of years assuming subsidence rates of between 1 and 5 cm day 1 land surface subsidence of between c 95 and c 475 m can be expected to develop within the 26 year time period

channel response to increased and decreased bedload supply from land use change contrasts between two catchments abstract the catchments of pine creek idaho usa 200 km 2 and the drome river in the drome department france 1640 km 2 illustrate contrasting changes in land use bedload sediment production and channel response hard rock mining began in the catchment of pine creek near the end of the 19th century and together with road construction timber harvest and historically heavy grazing of uplands resulted in increased tributary bedload yield increased bedload migrating to the channel combined with removal of large cedar trees on the floodplain resulted in channel instability which propagated downstream over a period of decades on many reaches of pine creek active channel width has increased by over 50 since 1933 over roughly the same time period the drome river catchment was extensively reforested after at least one century of denudation and heavy grazing and numerous check dams were constructed on torrents to reduce erosion as a result the drome river has experienced a reduction in bedload sediment supply since the late 19th century in addition gravel has been extracted from some reaches consequently the channel has degraded and gravel bars have been colonized with woody riparian vegetation channel widths in wide braided reaches decreased from 1947 to 1970 by 60 on pine creek channel instability has resulted in bank erosion exposing contaminated mine tailings and increased flood hazard on the drome river degradation has undermined bridges and embankments and lowered the water table in areas dependent on groundwater for irrigation resulting in loss of 6 million m 3 of groundwater storage since 1960 though they differ in drainage area by nearly an order of magnitude pine creek and the drome river provide an excellent contrast in that they represent two sides of an epicycle of alluvial sedimentation set off in each case by land disturbance in both cases the most recent channel changes though in opposite directions were viewed as negative by river managers on pine creek managers have removed or protected from erosion mine tailings and have attempted to train the stream into a more stable channel and most rock waste piles the principal sediment sources have recently been controlled on the drome river managers have prohibited gravel mining and adopted new policies to permit coarse sediment to migrate through the river system

extreme methane deuterium nitrogen and helium enrichment in natural gas from the homorod seep romania abstract methane ch 4 in terrestrial environments whether microbial thermogenic or abiogenic exhibits a large variance in c and h stable isotope ratios due to primary processes of formation isotopic variability can be broadened through secondary post genetic processes such as mixing and isotopic fractionation by oxidation the highest and lowest 13 c and 2 h or d deuterium concentrations in ch 4 found in various geologic environments to date are defined as natural terrestrial extremes we have discovered a new extreme in a natural gas seep with values of deuterium concentrations d ch4 up to 124 that far exceed those reported for any terrestrial gas the gas seeping from the small homorod mud volcano in transylvania romania also has extremely high concentrations of nitrogen 92 vol and helium up to 1 4 vol carbon isotopes in ch 4 c 2 h 6 and co 2 and nitrogen isotopes in n 2 indicate a primary organic sedimentary origin for the gas a minor mantle component is suggested by the 3 he 4 he ratio r ra 0 39 both thermogenic gas formation modeling and rayleigh fractionation modeling suggest that the extreme deuterium enrichment could be explained by an oxidation process characterised by a d ch4 and 13 c ch4 enrichment ratio h c of about 20 and may be accounted for by abiogenic oxidation mediated by metal oxides all favourable conditions for such a process exist in the homorod area where increased heat flow during pliocene quaternary volcanism may have played a key role finally we observed rapid variations within 1 h in c and h isotope ratios of ch 4 and in the h 2 s concentrations which are likely caused by mixing of the deep oxidized ch 4 n 2 h 2 s he rich gas with a microbial methane generated in the mud pool of one of the seeps we hypothesize that the unusual features of homorod gas can be the result of a rare combination of factors induced by the proximity of sedimentary organic matter mafic metal rich volcanic rocks and salt diapirs leading to the following processes a primary thermogenic generation of gas at temperatures between 130 and 175 c b secondary alteration through abiogenic oxidation likely triggered by the neogene quaternary volcanism of the eastern transylvanian margin and c mixing at the surface with microbial methane that formed through fermentation in the mud volcano water pool the homorod gas seep is a rare example that demonstrates how post genetic processes can produce extreme gas isotope signatures thus far only theorized and that extremely positive d ch4 values cannot be used to unambiguously distinguish between biotic and abiotic origin

strike slip faulting as a trigger mechanism for overpressure release through piercement structures implications for the lusi mud volcano indonesia piercement structures such as hydrothermal vent complexes pockmarks and mud volcanoes are found in various geological settings but are often associated with faults or other fluid focussing features this article aims to investigate and understand the mechanisms responsible for the formation of piercement structures in sedimentary basins and the role of strike slip faulting as a triggering mechanism for fluidization for this purpose four different approaches were combined fieldwork analogue experiments and math