Tectonic Pressure Research Articles

Earthquake on August 6, 2022 in the zone of the West Timan overthrust

On August 6, 2022, an earthquake was registered in Komi Republic, in the Udora district. Data from 17 seismic stations with epicentral distances from 227 to 1142 km were involved in processing the seismic event on August 6. The azimuth environment is uneven, the maximum azimuth gap is GAP=111.8°. As a result of instrumental processing, the following parameters were obtained: coordinates 64.023°N, 50.091°E, time at the source t0 =10:21:32 (UTC), depth h=14 km, energy class according to T.G. Rautian KR=10.2, local magnitude ML=3.6, error ellipse Azmajor=40°, Rminor=6.2 km, Rmajor=10.5 km. According to our calculations, the seismic event occurred in the middle reaches of the river Mezen, on the territory of the state natural reserve of regional significance “Udorsky”. The nearest settlements to the epicenter are located only 50 km away and the residents did not feel the earthquake. This area is not mining, so the seismic event is classified by us as a “tectonic earthquake”. The earthquake is confined to the West Timan thrust zone, which is a collision suture of the Russian and Pechora plates. The source at a depth of 14 km is located in the region of pericratonic subsidence covering the northeastern margin of the Russian Plate and the Kanino-Timan belt; on the boundary of the basement of the Mezen syneclise and the Timanid complex thrust over it. The earthquake may have been caused by tectonic pressure from the Pechora plate. This is the first earthquake in the West Timan thrust zone. Earthquakes occur mainly in the northeast of the Russian Plate, within the Volga-Ural anteclise, Mezen and Moscow syneclise. In addition, although the recorded earthquakes are mostly low-magnitude, they reflect the modern tectonic activation of the earth’s crust.

Fluctuation in the fluid and tectonic pressures in the South Almora Thrust Zone (SATZ), Kumaun Lesser Himalaya; paleoseismic implications

This study uses veins, striated faults, and fluid inclusions (FIs) for deciphering the tectonic stresses and the role of fluids in the evolution of the South Almora Thrust Zone (SATZ). The paleostress analysis implies that the SATZ bears a record of four different stress states. The syntectonic fluids preserved in the fluid inclusions in the quartz veins are predominantly aqueous-carbonic saline with a minor amount of methane detected in Raman spectroscopy. FIs showing the variable and uniform degrees of fill were entrapped as the immiscible and miscible aqueous-carbonic fluids, respectively. Microthermometry on FIs implies a considerable fluctuation in fluid pressure during the evolution of the SATZ. The absolute paleostress magnitude, estimated by the 3-D Mohr circle reconstruction, substantiates fluctuation in the ambient stress, indicating the role of tectonic stress. The implosion and explosion textures in fluid inclusions, fluid pressure fluctuations, and tectonic stress fluctuations are attributed to multiple seismic events that occurred at a depth of 7–13 km during the Late Oligocene-Early Miocene (21–25 Ma).

Calculation of tectonic stresses in the earth’s crust of SouthWestern Uzbekistan

In this article, based on accounting, the interaction of the Earth’s crust blocks is limited by the deep breaks in the form of three-layer panels. The analysis dependences for tectonic pressure on elasticity parameters and the Earth’s crust layers capacity were obtained using the hypothesis of linear changes of deformations on the height of panels and the elasticity for bottom layers of the Earth’s crust. This paper considers the elastic interaction of crustal blocks bounded by deep faults in the form of three-layer panels. Using the hypothesis of linear measurement of deformations along with the height of the board and the elastic limit for the lower layer of the Earth’s crust, calculated dependences for tectonic stresses on the elasticity and thickness of the layers of the Earth’s crust are obtained.

INFLUENCE OF TECTONIC DISTURBANCES OF COAL LAYER ON HIS GAS DYNAMIC STATE

Problem Statement and Purpose. At one of the coal mines of the Donetsk basin, there was a sudden release of coal and gas. The peculiarity of this case is that the accident happened in the place of the alleged development of a geological disturbance, but without any visible signs of this. Inspection of the ejection site and adjacent horizons made it possible to conclude that the emergency site is located in the place of the plicative disturbance development. Thus, it is necessary to study in more detail the influence of disturbed zones hidden nature on the gas-dynamic state of the reservoir, as well as to develop and implement methods for determining such zones. Data & Methods. To achieve this goal, a new method was tested, based on the property of structureless substances to form crystal-like units. This phenomenon has been studied for decades; therefore, such new formations have long been given the name quasicrystals. It was noted that the increase in the concentration of such forms is associated with the presence of geological disturbances. Consequently, the increase in quasicrystals in the rock is an indicator of its disturbance due to the influence of tectonic pressure. Thus, in order to test the technique and reveal the hidden geological disturbance of the coal seam, coal samples were taken, microstructural features were studied, and the strength of the coal seam was measured at 56 points. Result. As a result the values of the concentration of quasicrystals, data on the strength of the formation were obtained, a schematic map of the development of the disturbance in this area was built, its contours were determined, the center of the disturbed zone was identified and the role of such disturbances in the outburst hazard of the formation was substantiated. It has been established that geological disturbances, even of plicative nature, have a high degree of fracturing. Such pores and cracks in coal reduce the strength properties and are able to concentrate sufficient volumes of gas for manifestation of GDP.

Tectonic pressure gradients during viscous creep drive fluid flow and brittle failure at the base of the seismogenic zone

AbstractFluid-pressure cycles are commonly invoked to explain alternating frictional and viscous deformation at the base of the seismogenic crust. However, the stress conditions and geological environment of fluid-pressure cycling are unclear. We address this problem by detailed structural investigation of a vein-bearing shear zone at Sagelvvatn, northern Norwegian Caledonides. In this dominantly viscous shear zone, synkinematic quartz veins locally crosscut mylonitic fabric at a high angle and are rotated and folded with the same sense of shear as the mylonite. Chlorite thermometry indicates that both veining and mylonitization occurred at ∼315–400 °C. The vein-filled fractures are interpreted as episodically triggered by viscous creep in the mylonite, where quartz piezometry and brittle failure modes are consistent with low (18–44 MPa) differential stress. The Sagelvvatn shear zone is a stretching shear zone, where elevated pressure drives a hydraulic gradient that expels fluids from the shear zone to the host rocks. In low-permeability shear zones, this hydraulic gradient facilitates build-up of pore-fluid pressure until the hydrofracture criterion is reached and tensile fractures open. We propose that hydraulic gradients established by local and cyclic pressure variations during viscous creep can drive episodic fluid escape and result in brittle-viscous fault slip at the base of the seismogenic crust.

Deep subduction, melting, and fast cooling of metapelites from the Cima Lunga Unit, Central Alps

AbstractThe Cima Lunga unit in the Central Alps is dominated by quartzofeldspathic gneisses with subordinate mafic, ultramafic, and metacarbonate rocks. Only mafic and ultramafic lithologies were thought to preserve clear evidence of Alpine high‐P metamorphism. This led to the questions of whether the different rock types were subducted and exhumed as a coherent unit or underwent different pressure–temperature (P–T) histories. New petrological and geochemical data from a metapelite associated with garnet peridotite from Cima di Gagnone (Cima Lunga unit, Switzerland) were obtained using major and trace element mapping. Complex zoning patterns in garnet and white mica are observed. In particular, high Ti content in phengite and increasing P, Zr, and HREE contents in pyrope‐rich garnet indicate that this metapelite underwent high‐P and high‐T (HP–HT) metamorphism involving fluid‐fluxed partial melting. A P–T path is reconstructed by combining textural analysis with petrological–geochemical data and thermodynamic simulations. We show that the mineral record preserves an evolution from prograde to HP–HT peak conditions (2.7 ± 0.1 GPa and 800℃) followed by near‐isobaric cooling (~2.5 GPa and 700–750℃) prior to decompression (1.0 GPa and ~620℃). The reconstructed P–T path suggests that the studied metapelites were subducted to depths where the slab gets heated by proximity to asthenospheric mantle related to slab break‐off. This heating resulted in the dehydration of chlorite‐ to garnet peridotite and the liberated fluids triggered partial melting in the associated metapelites, which might have favoured the fast exhumation of the entire Cima Lunga unit. Metapelites and garnet peridotite from Cima di Gagnone underwent a common prograde to peak and retrograde P–T path without significant tectonic pressure difference between the different lithologies, and deviation from lithostatic pressure is excluded. Lastly, the peak metamorphic conditions of metapelite from Cima di Gagnone are comparable with P–T estimates of ultramafic lithologies from the southern Adula nappe and the Dascio Bellinzona zone, thus opening new scenarios for the geodynamic interpretation of the Central Alps.

Development of an intra-carbonate detachment during thrusting: The variable influence of pressure solution on deformation style, Khao Khwang Fold and Thrust Belt, Thailand

Abstract Classic detachment zones in fold and thrust belts are generally defined by a weak lithology (typically salt or shale), often accompanied by high over-pressures. This study describes an atypical detachment that occurs entirely within a relatively strong Permian carbonate lithology, deformed during the Triassic Indosinian orogeny in Thailand under late diagenetic-anchimetamorphic conditions. The key differences between stratigraphic members that led to development of a detachment zone are bedding spacing and clay content. The lower, older, unit is the Khao Yai Member (KYM), which is a dark-gray to black, well-bedded, clay-rich limestone. The upper unit, the Na Phra Lan Member (NPM), comprises more massive, medium- to light-gray, commonly recrystallized limestones and marble. The KYM displays much tighter to even isoclinal, shorter-wavelength folds than the NPM. Pressure solution played a dominant role throughout the structural development—first forming early diagenetic bedding; later tectonic pressure solution preferentially followed this bedding instead of forming axial planar cleavage. The detachment zone between the two members is transitional over tens of meters. Moving up-section, tight to isoclinal folds with steeply inclined axial surfaces are replaced by folds with low-angle axial planes, thrusts, and thrust wedging, bed-parallel shearing, and by pressure solution along bedding-parallel seams (that reduce fold amplitude). In outcrops 100–300 m long, reduction of line-length shortening on folds from >50% to <10% shortening upwards indicates that deformation in the NPM is being accommodated differently from the KYM, probably predominantly by shortening on longer wavelength and/or spacing folds and thrusts, given the low amount of strain observed within the NPM, which excludes widespread layer-parallel thickening.

Blastomylonite Complexes of the Western Yenisei Ridge (Eastern Siberia, Russia): Geological Position, Metamorphic Evolution and Geodynamic Models

Metapelites and metabasites within the Yenisei regional shear zone of the Yenisei Ridge underwent strong deformations with substrate recrystallization and blastomylonite formation during the Ediacaran. The geostructural, petrological, and isotopic–geochronological characteristics of development of the Late Neoproterozoic blastomylonite complexes marking the junction zone of the paleocontinental and paleoceanic sectors of the Yenisei Ridge have been analyzed. Two zones of heterogeneous blastomylonite complexes have been recognized from west to east, in order of increasing distance from the paleoceanic structures: (I) high-baric complexes of the suture zone and (II) frontal (above-suture) medium-baric and medium- to low-temperature complexes. The established differences in the Р–Т parameters of metamorphism between strongly and weakly deformed rocks were interpreted using well-known geodynamic models based on different tectonic mechanisms. As a result of the analysis, we found that the polychronous dynamic metamorphism of gneisses of the Angara–Kan block in the south and formation of the bulk of blastomylonites in the northern segment of the shear zone in the Northern Yenisei Ridge occurred with a 1.5–3 kbar increase in pressure along with insignificant increase in temperature and low metamorphic gradient dT/dH < 10°C/km compared to the background values of earlier regional metamorphism. This was probably due to crustal thickening as a result of rapid thrusting/subduction, followed by rapid uplift. The maximum excess values of the thermodynamic parameters of metamorphism were established in apometabasite tectonites of the suture zone with relict glaucophane schist associations that underwent metamorphism with a simultaneous significant increase in pressure by 3–5 kbar and temperature by 180–240°C with a higher dT/dH gradient of 15–20°C/km. Such excess Р–Т values could be due to progressive metamorphism, complicated by local heating of rocks during viscous deformations and excess oriented tectonic pressure over lithostatic in ductile shear zones. The data agree well with the results of numerical experiments, and this confirms the role of tectonic stress as an additional thermodynamic factor of metamorphic alterations in crustal suture zones.

Late Paleozoic Element Migration and Accumulation under Intracontinental Sinistral Strike‐slip Faulting in the West Junggar Orogenic Belt, NW China

AbstractThe migration, accumulation and dispersion of elements caused by tectonic dynamics have always been a focus of attention, and become the basis of tectono‐geochemistry. However, the effects of faulting, especially strike‐slip faulting, on the adjustment of geochemical element distribution, are still not clear. In this paper, we select the West Junggar Orogenic Belt (WJOB), NW China, as a case study to test the migration behavior of elements under tectonic dynamics. The WJOB is dominated by NE‐trending large‐scale sinistral strike‐slip faults such as the Darabut Fault, the Mayile Fault, and the Baerluke Fault, which formed during the intracontinental adjustment under N–S compression during ocean‐continental conversion in the Late Paleozoic. Geochemical maps of 13 elements, Al, W, Sn, Mo, Cu, Pb, Zn, As, Sb, Hg, Fe, Ni, and Au, are analyzed for the effects of faulting and folding on element distribution at the regional scale. The results show that the element distribution in the WJOB is controlled mainly by two mechanisms during tectonic deformation: first is the material transporting mechanism, where the movement of geological units is consistent with the direction of tectonic movement; second is the diffusion mechanism, especially by tectonic pressure dissolution driven by tectonic dynamics, where the migration of elements is approximately perpendicular or opposite to the direction of tectonic movement. We conclude that the adjustment of element distributions has been determined by the combined actions of transporting and diffusion mechanisms, and that the diffusion mechanism plays an important role in the formation of geochemical Au blocks in the WJOB.

A chemical and microbial characterization of selected mud volcanoes in Trinidad reveals pathogens introduced by surface water and rain water

Terrestrial mud volcanoes are unique structures driven by tectonic pressure and fluids from the deep subsurface. These structures are mainly found in active tectonic zones, such as the area near the Los Bajos Fault in Trinidad. Here we report a chemical and microbiological characterization of three mud volcanoes, which included analyses of multiple liquid and solid samples from the mud volcanoes. Our study confirms previous suggestions that at least some of the mud volcano fluids are a mixture of deeper salt-rich water and surficial/precipitation water. No apparent water quality differences were found between sampling sites north and south of a major geological fault line. Microbiological analyses revealed diverse communities, both aerobic and anaerobic, including sulfate reducers, methanogens, carbon dioxide fixing and denitrifying bacteria. Several identified species were halophilic and likely derived from the deeper salt-rich subsurface water, while we also cultivated pathogenic species from the Vibrionaceae, Enterobacteriaceae, Shewanellaceae, and Clostridiaceae. These microorganisms were likely introduced into the mud volcano fluids both from surface water or shallow ground-water, and perhaps to a more minor degree by rain water. The identified pathogens are a major health concern that needs to be addressed.

Ore bearing factors of breaking-block structures of the Ukrainian shield

Most ore occurrences and mineral deposits are known to be located in tectonic fault zones. In this regard, the article analyzes the ore content of regional and local fault zones developed in the megastructures of the Ukrainian shield: Podolsky, Volynsky, Ingulsky, Dnieprovsky, Priazovsky megablocks and Belotserkovsky-Odessky, Inguletsko-Krivorozhsky, Orekhovo-Pavlogradsky interblock zones. Geological and structural-tectonic features of megablocks and interblock suture zones are characterized; the main stages of their formation are highlighted. Based on the analysis of the distribution patterns of various deposits and ore occurrences in the fault-block tectonics of the Ukrainian Shield, ore-bearing factors and metallogenic features of megablocks and interblock suture zones, which are determined by the geodynamic regime of these structures, are established; specific megablocks and suture zones have their own distinctive features, and the metallogeny of megablocks differs from the metallogeny of interblock suture zones. The metallogeny of the megastructures of the Ukrainian shield and the ore content of regional and local structures is due to a combination of a number of factors of various importance. The main ones are the processes of evolution of mantle fluids and the degree of oxidation of crustal products during geological time. Of great importance was the level of erosion cut of specific structures, which determined the physicochemical conditions for the concentration of specific ore elements.The metallogeny of various fault zones is determined by the combination of a number of favorable factors for the accumulation of metals in geological time and space. The most important ore-concentrating factors are the composition and quantitative ratio of ortho- and para-rocks and the presence in them of above-clark contents of characteristic metals; fault evolution, in which the mobility of metals and their concentration at less deep levels are activated; confinement to faults of igneous rocks; degree of eroded blocks; physicochemical features of fault rocks and uneven distribution of tectonic pressures; conditions and nature of the deformation of structures; lateral structure of faults.

An integrated approach to evaluate the Aji-Chai potash resources in Iran using potential field data

This work presents an integrated application of potential field data to discover potash-bearing evaporite sources in Aji-Chai salt deposit, located in east Azerbaijan province, northwest of Iran. Low density and diamagnetic effect of salt minerals, i.e. potash, give rise to promising potential field anomalies that assist to localize sought blind targets. The halokinetic-type potash-bearing salts in the prospect zone have flowed upward and intruded into surrounded sedimentary sequences dominated frequently by marl, gypsum and alluvium terraces. Processed gravity and magnetic data delineated a main potash source with negative gravity and magnetic amplitude responses. To better visualize these evaporite deposits, 3D model of density contrast and magnetic susceptibility was constructed through constrained inversion of potential field data. A mixed-norm regularization technique was taken into account to generate sharp and compact geophysical models. Since tectonic pressure causes vertical movement of the potash in the studied region, a simple vertical cylindrical shape is an appropriate geometry to simulate these geological targets. Therefore, structural index (i.e. decay rate of potential field amplitude with distance) of such assumed source was embedded in the inversion program as a geometrical constraint to image these geologically plausible sources. In addition, the top depth of the main and the adjacent sources were estimated 39 m and 22 m, respectively, via the combination of the analytic signal and the Euler deconvolution techniques. Drilling result also indicated that the main source of potash starts at a depth of 38 m. The 3D models of the density contrast and the magnetic susceptibility (assuming a superficial sedimentary cover as a hard constraint in the inversion algorithm) demonstrated that potash source has an extension in depth less than 150 m.

Pressure and equilibrium in deforming rocks

AbstractIt is widely proposed that tectonic pressure (the difference between the mean stress and the pressure arising from a lithostatic load) is large, and has a significant influence on mineral phase equilibria in deforming metamorphic rocks. The implication/assertion is that the mean stress is equivalent to the thermodynamic pressure which characterizes mineral phase equilibria and is a measure of how the energy changes as the volume changes. We distinguish two useful thermodynamic pressures. The first is an equilibrium thermodynamic pressure, characteristic of non‐dissipative systems and related directly to equilibrium values of the chemical potentials that define stable, equilibrium phase assemblages. The second is a non‐equilibrium thermodynamic pressure characteristic of dissipative systems with zero net entropy production and related to non‐equilibrium chemical potentials that define stable non‐equilibrium phase assemblages. In many dissipative metamorphic systems discussed in the literature, the concepts of thermodynamic pressure and chemical potential are not usefully defined because the system is not at equilibrium and/or no volume change is involved in the deformation. The conclusion of this note is that the influence of tectonic pressure on phase equilibria is minor. The role of tectonic pressure is an important issue but is only relevant to phase equilibrium when an equilibrium thermodynamic pressure can be defined; in such cases, the influence of tectonic pressure is small compared to many proposals in the literature. Except for elastic deformations, the mean stress is not useful in discussing mineral phase equilibrium.

Metamorphic record of catastrophic pressure drops in subduction zones

When deeply buried in subduction zones, rocks undergo mineral transformations that record the increase of pressure and temperature. The fact that high-pressure metamorphic parageneses are found at the Earth’s surface proves that rock burial is followed by exhumation. Here we use analysis of available data sets from high-pressure metamorphic rocks worldwide to show that the peak pressure is proportional to the subsequent decompression occurring during the initial stage of retrogression. We propose, using a simple mechanical analysis, that this linear relationship can be explained by the transition from burial-related compression to extension at the onset of exhumation. This major switch in orientation and magnitude of principal tectonic stresses leads to a catastrophic pressure drop prior to actual rock ascent. Therefore, peak pressures are not necessarily, as commonly believed, directly dependent on the maximum burial depth, but can also reflect a change of tectonic regime. Our results, which are in agreement with natural data, have significant implications for rock rheology, subduction zone seismicity, and the magnitudes of tectonic pressures sustained by rocks. Current views of subduction dynamics could be reconsidered in that perspective. Rocks are altered by high pressure during subduction. Analysis of exhumed metamorphic rocks suggests that the peak pressures recorded within minerals mark a change in tectonic regime within a subduction zone, rather than burial depth.

Development of sedimentary basins: differential stretching, phase transitions, shear heating and tectonic pressure

AbstractClassical models of lithosphere thinning predict deep synrift basins covered by wider and thinner post‐rift deposits. However, synextensional uplift and/or erosion of the crust are widely documented in nature (e.g. the Base Cretaceous unconformity of the NE Atlantic), and generally the post‐rift deposits dominate basins fills. Accordingly, several basin models focus on this discrepancy between observations and the classical approach. These models either involve differential thinning, where the mantle thins more than the crust thereby increasing average temperature of the lithosphere, or focus on the effect of metamorphic reactions, showing that such reactions decrease the density of lithospheric rocks. Both approaches result in less synrift subsidence and increased post‐rift subsidence. The synextensional uplift in these two approaches happens only for special cases, that is for a case of initially thin crust, specific mineral assemblage of the lithospheric mantle or extensive differential thinning of the lithosphere. Here, we analyse the effects of shear heating and tectonic underpressure on the evolution of sedimentary basins. In simple 1D models, we test the implications of various mechanisms in regard to uplift, subsidence, density variations and thermal history. Our numerical experiments show that tectonic underpressure during lithospheric thinning combined with pressure‐dependent density is a widely applicable mechanism for synextensional uplift. Mineral phase transitions in the subcrustal lithosphere amplify the effect of underpressure and may result in more than 1 km of synextensional erosion. Additional heat from shear heating, especially combined with mineral phase transitions and differential thinning of the lithosphere, greatly decreases the amount of synrift deposits.

Unexpected behaviors of stimulated fractures in the high-stress Cooper Basin

Much of the industry's experience with fracture stimulation comes from basins with low stress and normal fault regimes. The Cooper Basin has high differential stress. It is in a strike-slip fault regime for shallower reservoir levels and a reverse-fault regime for the deeper reservoirs of a new basin-centered gas play. This difference in stress leads to a difference in fracture-stimulation results. Presented here are data on Cooper tectonic stress, rock strength, pore pressure, natural fractures, and borehole breakouts all of which impact fracture-stimulation treatments. Several unexpected behaviors of Cooper fracture stimulations then are discussed and some mitigation suggested. The reader is assumed to be a geoscientist with an interest in this topic, not necessarily an expert in geomechanics or fracture stimulation.

Bifocal earthquake source and its shock precursors

The replacement of excess porous space, appeared due to dilatant fracturing, creates the second zone of consolidation inside the earthquake source volume. Here the elastic energy for the future main shock is stored and the source as a whole gets a real bifocal structure. At the stage of intermediate precursors, water is flowing from a zone of consolidation into dilatant cracks, perceiving its tectonic loading. This process develops proportionally to a root square of time due to water flows as it was marked in all manuals on earthquake mechanics. The radon emission marks out a dilatant zone from preliminary cracks net in surrounding rocks.Dilatant loosening process cannot compensate gradually unloading of the consolidation zone because of their rheological differences. As result, the dynamic process in the source is unstable especially at the stage of short-term precursors. Partly closing of the arisen cracks and by simultaneous reorientation of displacements indicates this process. Penetration of waters up to front of cracks accelerates their growth and causes radon output. Then there comes a stage of short-term precursors of the main shock: collapsing of the staying cracks occurs. Their squeezing exceeds the common level of tectonic pressure growth. At the collapse, moving water masses raises a magnetic signal (global at big magnitudes М > 6), measured at stations of supervision carried on thousands of km. The hydrodynamic nature of magnet signal is supported by analogous effect in a tsunami of salt marine waters.In the form of the review of natural dates and measurements, the consequence of events in bifocal earthquake source is stated.

Evidence of a plate-wide tectonic pressure pulse provided by extensometric monitoring in the Balkan Mountains (Bulgaria)

Abstract The EU-TecNet monitoring network uses customized three-dimensional extensometers to record transient deformations across individual faults. This paper presents the first results from two newly established monitoring points in the Balkan Mountains in Bulgaria. The data from Saeva Dupka, recorded across an EEN-WWS striking fault, show sinistral strike-slip along the fault and subsidence of the southern block. Much of the subsidence occurred around the time of the distal MW = 5.6 Pernik Earthquake. An important transient deformation event, which began in autumn 2012, was reflected by significant compression and following extension, across the monitored fault. The data from Bacho Kiro, recorded across a NE–SW striking fault, show sinistral strike-slip along the fault and subsidence of the north-western block. The same important deformation event was reflected by changes in the strike-slip, dip-slip, and horizontal opening/closing trends. These results have been compared to data from other monitoring points in the Western Carpathians, External Dinarides, and Tian Shan. Many of the sites show evidence of simultaneous displacement anomalies and this observation is interpreted as a reflection of the plate-wide propagation of a tectonic pressure pulse towards the end of 2012.

WHEN THE DISASTER TREATMENT IN THE HEAD OF EYES: THE EFFORTS OF MITIGATION POLICY AND REDUCTION OF THE DISASTER RISK IN PADANG CITY

INTRODUCTION:Indonesia is situated on the three major straights of different world those are Eurasian tectonic straight, Iindo-Australian tectonic, and pasific straight affected Indonesia as a territory of troubled natural disaster especially earthquake, tsunamy and volcanic erruption (Sutikno in Napsiah, 2015:6). In connected with them that one of such situated city is Padang, West Sumatra. The earthquake happened in September 30, 2009 at 7.6 richter scale quaked West Sumatra Province. The greatest demage affected by earthquake was in 13 of 19 regencies/cities and stroke victims more than 1.100 people. The affected region of the most serious demage were Padang City, Pariaman, and Padang Pariaman Regency. The demage and disavdvantage in West Sumatra was approximately 21.6 quintillions or equivalently US$ 2.3 billions (Danhas 2011). Accordingly, the government of Padang City began paying attention to the earthquake disaster probabilities occuring in the next time because of regional condition at the troubled disaster.Besides, the experts research explained that Padang City and West Sumatra generally have high risk towards threat of earthquake with 8,9 richter scale. The potency is at the matching Euroasian straight and Indo-Australia, exactly in Mentawi archipelago. Strong assesment, the earthquake will result in great enough tsunamy wave that can destroy Padang City, such as tsunamy happened in Nangro Aceh Darussalam in the last 2004. Meanwhile, an expert of the earthquake of Indonesian Institute of Science (IIS) Danny Hilman thought that the great threating eaerthquake in the west Sumatra is increasingly nea.. This matter concerning with ongoing the great earthquake potency that isn't free from Mentawai segment. This segment stored the earthquake potency with 30 times over energy greater compared with earthquake in Padang last years. The great earthquake in (subduksi zone) Mentawai is always again and again goes along yearly cycle. The research result showed that the period of great earthquakes in that region ended in 1797 and 1833. While the 2007 earthquake in Mentawai region only lost three quarter of energy amount of accumulated tectonic pressure. The earthquake predicted resulting in tsunamy wave that swept the area in the West Sumatra beach at 5 kilometers circle from the beach edge. Padang is one of the threated city struck by tsunamy impact (vivanews.co.id, 2015).Accordingly, to avoid the worst probability that is going tobe caused by disaster so the thing todo for Padang City Government is to implement the policy of managing disaster based disaster mitigation, where mitigation (the efforts of reducing disaster impact). Mitigational action can be in specific programming type. This is tobe embodied in order that when the disaster occurs, this program can reduce the people victims and demages. There are two approches to do for Padang City in such mitigational policy, Structural Mitigation (building chekdam, river embankment, barrage, shelter, EWS, map, ect.) and Non Structural Mitigation (making regulation, lay -out, training, socialization (including spiritual mitigation). (BPBDPK Kota Padang, 2015).DISASTER MANAGEMENT:According to UNISDR (2009) that the definition of disaster is trouble towards people or community that caused occuring disadvantage and impacting spirit passing away, economy, and environment broadly, that excesses the impacted people abilities to face it by using their own resources.In many disasterous occuranes, the role that government does in terms of public policy and public administration to manage disaster is very important and great. There are various important paradigm changes tobe noticed in reducing disasterous risk (Pujiono, 2007).1. From emergency respond tobe disaster management : disaster management can not focus only on emergency management anymore (emergency respond) when the disaster has occured, except more to reducing the overall disasterous risk of the risk observation, prevention, mitigation, readiness, respond, rehabilitational restoration and reconstruction. …

Isolation of Anaerobic Bacteria from Terrestrial Mud Volcanoes (Salse di Nirano, Northern Apennines, Italy)

Terrestrial mud volcanoes and salses are unique inland sites of methane and saline water seepage, driven by tectonic pressure and methane from deep subsurface oil reservoirs. These structures are mainly found in active nappe tectonic zones, like in the foothills of the Northern Apennines. Fluid samples, taken anaerobically from the Nirano mud volcano field located in the foreland of the Northern Apennines, contain low numbers of bacterial cells. Representative strains were enriched under anaerobic conditions in culture media based on the composition of the mud volcano fluid. Anaerobic fermentative organisms, partially involved in cycling of sulfur compounds, namely Desulfovibrio and clostridial strains, were enriched and isolated. Two isolates of Clostridium thiosulfatireducens- and Desulfovibrio psychrotolerans-related strains were retrieved from enrichment cultures. Isolated sulfate reducers form aggregates, composed of bacterial biomass, extracellular polysaccharides and a mineral matrix. Besides some typical “contaminants” from topsoil, the Nirano mud volcano fluids contain culturable bacteria related to organisms typical for other sediments of saline systems and/or oil reservoirs.