Active Tectonic Zones Research Articles

Comparison slide zones by Nilsen method with active tectonic zones produce of Smf index

Slide zones under title erosion types related to more active tectonic factors for example stream length-gradient (Sl),ratio of valley-floor width to valley height (Vf), drainage basin shape (Bs), mountain front sinuosity (Smf), drainage basin asymmetry (Af) and hypsometric integral (Hi). This research is noticeable comparison produce slide zones by Nilsen. The active tectonic zones produce from Smf index under title one of the important active tectonic factors. Determination landform of geometry or morphometry factors is the one of best method for study and evaluation active tectonic. The first provided Dem maps in GIS software by topography, geology, tectonic maps participant with field activities. Then provided active tectonic map by Smf index into three class A, B, C and landslide hazard zonation map into five class stable zone, generally stable zone, stable moderately stable zone, moderately un-stable zone and talented to liquefaction zone. Comparison and conformity landslide hazard zonation map with hazard zonation into Smf index showed about percent 71(51120 hectare) moderately unstable zone and talented for liquefaction zone settled in A zone Smf map and percent 29 (20880 hectare) remained settled sequential percent 18 (12960 hectare) and percent 11 (7920 hectare) in B, C zone of hazard zonation active tectonic produce from Smf index. In other word in research showed relationship landslide zones produce landslide hazard zonation by Nilsen to active tectonic zones by Smf index in the study region.

Study of Local Seismic Events in Lithuania and Adjacent Areas Using Data from the PASSEQ Experiment

The territory of Lithuania and adjacent areas of the East European Craton have always been considered a region of low seismicity. Two recent earthquakes with magnitudes of more than 5 in the Kaliningrad District (Russian Federation) on 21 September 2004 motivated re-evaluation of the seismic hazard in Lithuania and adjacent territories. A new opportunity to study seismicity in the region is provided by the PASSEQ (Pasive Seismic Experiment) project that aimed to study the lithosphere–asthenosphere structure around the Trans-European Suture Zone. Twenty-six seismic stations of the PASSEQ temporary seismic array were installed in the territory of Lithuania. The stations recorded a number of local and regional seismic events originating from Lithuania and adjacent areas. This data can be used to answer the question of whether there exist seismically active tectonic zones in Lithuania that could be potentially hazardous for critical industrial facilities. Therefore, the aim of this paper is to find any natural tectonic seismic events in Lithuania and to obtain more general view of seismicity in the region. In order to do this, we make a manual review of the continuous data recorded by the PASSEQ seismic stations in Lithuania. From the good quality data, we select and relocate 45 local seismic events using the well-known LocSAT and VELEST location algortithms. In order to discriminate between possible natural events, underwater explosions and on-shore blasts, we analyse spatial distribution of epicenters and temporal distribution of origin times and perform both visual analysis of waveforms and spectral analysis of recordings. We show that the relocated seismic events can be grouped into five clusters (groups) according to their epicenter coordinates and origin and that several seismic events might be of tectonic origin. We also show that several events from the off-shore region in the Baltic Sea (at the coasts of the Kaliningrad District of the Russian Federation) are non-volcanic tremors, although the origin of these tremor-type events is not clear.

THE APPLICATION OF TM DATA TO ACTIVE TECTONIC ZONES IN TIBET

TM data are major remote sensing data now and can completely meet the precision for the identification of the active tectonic zones in Tibet. Tibet has special geographical and environmental background, and possesses a complete set and wide distribution of active tectonic zones. As conditions are extremely bad, people can hardly approach there. Applying the remote sensing technology and the high-precision TM image, we can achieve the purpose of simple imaging, high resolution, wide projection and low cost. Thus, the rapid and accurate identification of all kinds of active tectonic zones can be realized. The method has overcome such shortcomings of the traditional surveying methods as long periodicity, high cost and impossibility of making insite investigation at many places.

Radon Monitoring as the Earthquake Precursor in Fault Line in Western Turkey

Variations in radon concentrations near the earth's surface can provide important information about seismic activities. Continuous monitoring of radon concentrations is one of the important steps in predicting earthquake mechanisms. This study monitored the radon concentration of an active tectonic zone in western Turkey. Four sampling stations in the seismic area, of the Tuzla fault line, were selected for radon monitoring. The online radon monitoring system was placed at Cumalý station. Concurrently, the radon concentrations in the soil gas were continuously measured using LR-115 nuclear track detectors and an online radon measurement system. Data obtained from Bogazici University Kandilli Observatory and Earthquake research Institute was incorporated in the analysis to correlate with the collected radon concentration. The radon concentrations were measured using solid-state nuclear track films (LR-115) in the soils of thermal water fields, which varied from 40 track cm -2 week -1 to 1580 track cm -2 week -1 .

Spatial-temporal variation of the land surface temperature field and present-day tectonic activity

This study attempts to acquire information on tectonic activity in western China from land surface temperature ( LST) field data. On the basis of the established relationship between heat and strain, we analyzed the LST distribution in western China using the satellite data product MODIS/Terra. Our results show that: 1. There are departures from annual changes of LST in some areas, and that these changes are associated with the activity of some active tectonic zones. 2. When annual-change background values caused by climate factors are removed, the long-period component ( LST LOW) of temperature residual (Δ T) of the LST is able to serve as an indicator for tectonic activity. We have found that a major earthquake can produce different effects on the LST fields of surrounding areas. These effects are characterized by both rises and drops in temperature. For example, there was a noteworthy temperature decline associated with the Sumatran M9 earthquake of 2004 in the Bayan Har-Songpan block of central Tibetan Plateau. 3. On the other hand, the LST field of a single area may respond differently to major shocks occurring in different areas in the regions surrounding China. For instance, the Kunlun M 8.1 event made the LST on the Longmen Mountains fault zone increase, whereas the Zaisan Lake M 7.9 quake of 2003, and the Sumatran M 9 event of 2004, caused decreases in the same area’s LST. 4. The variations of land surface temperature ( LST) over time are different in different tectonic areas. These phenomena may provide clues for the study of tectonic deformation processes. On the basis of these phenomena, we use a combination of temperature data obtained at varied depths, regional seismicity and strain results obtained with GPS measurements, to test the information related to tectonic activity derived from variations of the LST field, and discuss its implications to the creation of models of regional tectonic deformation.

A review of international cases of fault reactivation during mining subsidence and fluid abstraction

Abstract Fault reactivation, during coal mining subsidence, has been documented in the coalfields of Great Britain for at least the past 150 years. This often results in the generation of a scarp, fissure, graben or compression hump on the ground surface. These features subsequently may severely damage houses, other structures, transport networks, utilities and land. An aim of this paper is to demonstrate that mining-induced fault reactivation does not exist only in Britain but has also been observed or recorded in many other parts of the world as a result of the mining of coal, metalliferous ore-bodies and the abstraction of fluids. Examples are provided from Europe, USA, Australia, Canada, South America, Caribbean, Africa, Asia and Russia. Fault reactivation as a result of the mining of coal is the most commonly recorded and this probably reflects the long, complex mining history that has taken place in the more densely populated and urbanized parts of Europe, where there has been a greater potential for fault reactivation to cause damage to the built environment. Less reported are the examples of fault reactivation caused by the mining of metalliferous ore-bodies in more remote and sparsely populated parts of the world. Here, reactivated faults tend to be of little consequence to people and structures, therefore there has not been the need for reactivated faults to be investigated. Fault reactivation caused by groundwater, brine, oil and gas abstraction (in the USA) generates some of the largest scarps, which are recorded to be up to some 16 km long and 1 m high. Where these occur in seismically active tectonic zones it may be difficult to distinguish faults generated by fluid abstraction and those generated by earthquake activity. This paper also aims to provide some clarity to the understanding of fault reactivation, by drawing attention to and summarizing the principal effects of mining-induced fault reactivation.

METHODOLOGY OF SITE-SPECIFIC SEISMIC HAZARD ANALYSIS FOR IMPORTANT CIVIL STRUCTURE

Note from the Editor The Indonesian archipelago is one of the most active tectonic zones in the world. Therefore to design an important (and dangerous) structure such as a nuclear power plan knowledge of the seismicity of the site is very important. This could be achieved by doing a site-specific seismic hazard analysis. A site-specific seismic hazard analysis is required in the design state in order to determine the recommended seismic design criteria of the structure. A complete and thorough explanation of the methodology to do a site-specific seismic hazard analysis is presented in this Technical Note Abstract in Bahasa Indonesia :

Rare earth elements in iron oxy−hydroxide rich sediments from the Marabasco River-Estuary System (pacific coast of Mexico). REE affinity with iron and aluminium

Rare earth elements (REE from La to Lu), Al and Fe were analysed in 35 surface sediment samples from the Marabasco River-Estuary system, located in the active tectonic zone of Cocos Plate near the active Colima Volcano. The Peña Colorada iron mine is found in the Marabasco watershed and the river sediments are enriched by iron oxy-hydroxides. The average REE content is 86.9 ± 26.8 mg·kg − 1 and 95.5 ± 50.3 mg·kg − 1 for river and estuarine sediments respectively, which is low in comparison to other tropical coastal systems. The REE light/heavy content ratios (L/H) of Marabasco sediments are also low with averages of 5.2 ± 0.8 (river) and 5.7 ± 0.9 (estuary) due to the minor presence of LREE. The REE signature of the sediment by normalisation with chondrite indicated a slight negative anomaly of Europium and the absence of a Cerium anomaly. REE concentrations in the Marabasco sediments show a strong correlation with Al and Fe, with LREE having a greater affinity for Fe and HREE for Al. This antagonism is REE-ordered by their atomic number sequence in the river sediment case. This has not been previously observed in the environment and the presence of magnetite and the iron oxy-hydroxide enrichment may enhance it. This did not occur in the estuary of the Marabasco mine region where Al and Fe are both well correlated.

Structural and geological characteristics of a “seismic gap” in the central part of the Kuril Island Arc

The results of the cruise of R/V Akademik M.A. Lavrentiev conducted by the Pacific Institute of Oceanology, Far East Division of the Russian Academy of Sciences and the Shirshov Institute of Oceanology, Russian Academy of Sciences in August to September 2005 are considered. The aim of the works was to specify the tectonic structure, seismogenic potential, and tsunamigenic hazard of the central segment of the Kuril Island Arc. The complex studies involved single-channel seismic profiling, gravimetry, magnetometry, detailed bathymetry, dredge sampling of sea-floor rocks and sediments, and gas geochemistry. Geophysical and geological data are reported. It was demonstrated that the target area is an active tectonic destruction zone, the zone boundaries were outlined, and the main internal structural and compositional heterogeneities were identified.

Formation of Hot Water Springs in Sri Lanka

As a wonderful gift of nature, several hot water springs occur in Sri Lanka, though it is not situated within a very active tectonic zone of the earth. The present research was conducted to model the formation of hot water springs in Sri Lanka based on geological and tectonic settings by using geological, geophysical and remote sensing techniques. It is found that the major boundary between Highland Complex and Vijayan Complex show multiple thrust planes and shear zones showing imbrecated lithological slices of both Highland Complex and Vijayan Complex. Other than the ductile structures, brittle fractures, joints and fault planes extend as mega lineament for several kilometers. These lineaments produce good secondary aquifer conditions with adequate porosity. The surface mapping and geophysical evidence of the lineaments show that they are very deep and interconnected. Thus it is proposed that structurally controlled hot water springs in Sri Lanka are associated with deep geologically weak zones of fracture or fault systems within the thrust boundary which shows some neo-tectonic activities.

MALPAS, J., FLETCHER, C. J. N., ALI, J. R. & AITCHISON, J. C. (eds) 2004. Aspects of the Tectonic Evolution of China. Geological Society Special Publication no. 226. vi+362 pp. London, Bath: Geological Society of London. Price £80.00, US $134.00; GSL members' price £40.00, US $67.00; AAPG/SEPM/GSA/RAS/EFG/PESGB members' price £48.00, US $80.00 (hard covers). ISBN 1 86239 156 4

MALPAS, J., FLETCHER, C. J. N., ALI, J. R. & AITCHISON, J. C. (eds) 2004. Aspects of the Tectonic Evolution of China. Geological Society Special Publication no. 226. vi+362 pp. London, Bath: Geological Society of London. Price £80.00, US $80.00 (hard covers). ISBN 1 86239 156 4 - Volume 142 Issue 5

Prospect on present-day crustal kinematics and dynamics research in Sichuan-Yunnan area with geodetic data

Combining the dense GPS and gravity observation data in Sichuan-Yunnan area, where there are the relatively complete active tectonic zones and seismic data, this paper applies the geodesy and geophysical inversion technique and the advanced numerical simulation to the synthesis study of geodesy inversion to find the dynamic process of tectonic movement and deformation in the area and finally to investigate the kinematics characteristic of the geological structure of different layer and different scale. This paper discusses the kinematics, dynamics model about the crustal movement of active blocks in Sichuan-Yunnan area and its adjacent areas.

Variational characteristics of shear-wave splitting on the 2001 Shidian earthquakes in Yunnan, China

In 2001 three earthquakes occurred in Shidian in Yunnan Province, which were the M S=5.2 on April 10, the M S=5.9 on April 12 and the M S=5.3 on June 8. Based on the data from the station Baoshan of Yunnan Telemetry Digital Seismograph Network, the variational characteristics of shear-wave splitting on these series of strong earthquakes has been studied by using the systematic analysis method (SAM) of shear-wave splitting. The result shows the time delays of shear-wave splitting basically increase with earthquake activity intensifying. However the time delays abruptly decrease immediately before strong aftershocks. It accords with the stress relaxation before earthquakes, which was found recently in study on shear-wave splitting. The result suggests it is significant for reducing the harm degree of earthquakes to develop the stress-forecasting on earthquake in strong active tectonic zones and economic developed regions or big cities under the danger of strong earthquakes.

Recent tectonic stress field and major earthquakes of the Bohai sea basin

The Bohai Sea basin is located in the east to the Cenozoic rift basin of North China. It is a inner-land sea basin formed during Late Quaternary time. In this basin there are numerous active faults and many major earthquakes have occurred. Its major active tectonic zones are the northern section of the NE trending Yingkou-Weifang fault zone, Miaoxibei-Huanghekou-Linyi fault zone, and NW striking Beijing-Penglai fault zone, which intersect at the center of the Bohai Sea basin. These tectonic zones subdivide the sea area into four secondary neotectonic areas, which are subject to the recent tectonic stress field. Using the data of 38 focal plane solutions and 75 drill stress measurements, and the result of numerical modeling, we analyze the recent tectonic stress field of this region. Our result shows that this stress field is characterized by dominant horizontal or nearly horizontal stress. Its compressive stress is in the direction NE60°–90°, and the tensional stress is in NS-NW30°. There are some differences of principal stress between secondary tectonic areas. A remarkable feature of the Bohai Sea basin is a conjugate shear rupture zone, which develops in the crust and is the major seismogenic structure.

Geochemical signature of orogenic hydrothermal activity in an active tectonic intersection zone, Alpine Fault, New Zealand

A highly faulted and fractured rock mass has developed at the intersection of the Alpine and Hope faults, two major active faults in the South Island, New Zealand. The Alpine Fault is an oblique dextral reverse fault at the late Cenozoic-Recent Pacific-Australian plate boundary. The Hope Fault is a strike-slip fault parallel to the plate convergence vector. Hydrothermal fluids driven by the active tectonic processes have passed through the fractured rock mass, causing localised rock alteration and vein formation. Mylonites in the Alpine Fault zone are crosscut by cm-scale veins of quartz and/or ankerite with minor sulphides, with cemented breccias in dilational jogs. Breccia clasts and immediate (cm-scale) host rocks have been variably impregnated with carbonates and quartz. This generation of veins, breccias and altered rocks is post-dated by cataclasite and fault gouge zones which have been cemented by calcite, illite, smectite and chamosite. Ankerite and calcite have δ18O between +10 and +30‰, and δ13C between 0 and −8‰. These minerals are inferred to have formed from water with variable components of both meteoric and crustally exchanged fluid. Rock alteration associated with ankerite–quartz veins has added arsenic (up to 200 ppm As), strontium, and some Y to the rocks. Host-rock mylonites (<2 ppm As) have been depleted in arsenic compared to their precursors (5–15 ppm As). This depletion of arsenic in the middle crust provides the source for arsenic in shallower-level vein systems.

Absence of a regional surface thermal high in the Baikal rift; new insights from detailed contouring of heat flow anomalies

Heat flow in active tectonic zones as the Baikal rift is a crucial parameter for evaluating deep anomalous structures and lithosphere evolution. Based on the interpretation of the existing datasets, the Baikal rift has been characterized in the past by either high heat flow, or moderately elevated heat flow, or even lacking a surface heat flow anomaly. We made an attempt to better constrain the geothermal picture by a detailed offshore contouring survey of known anomalies, and to estimate the importance of observed heat flow anomalies within the regional surface heat output. A total of about 200 new and close-spaced heat flow measurements were obtained in several selected study areas in the North Baikal Basin. With an outrigged and a violin-bow designed thermoprobe of 2–3-m length, both the sediment temperature and thermal conductivity were measured. The new data show at all investigated sites that the large heat flow highs are limited to local heat flow anomalies. The maximum measured heat flow reaches values of 300–35000 mW/m 2, but the extent of the anomalies is not larger than 2 to 4 km in diameter. Aside of these local anomalies, heat flow variations are restricted to near background values of 50–70 mW/m 2, except in the uplifted Academician zone. The extent of the local anomalies excludes a conductive source, and therefore heat transport by fluids must be considered. In a conceptual model where all bottom floor heat flow anomalies are the result of upflowing fluids along a conduit, an extra heat output of 20 MW (including advection) is estimated for all known anomalies in the North Baikal Basin. Relative to a basal heat flow of 55–65 mW/m 2, these estimations suggest an extra heat output in the northern Lake Baikal of only 5%, corresponding to a regional heat flow increase of 3 mW/m 2. The source of this heat can be fully attributed to a regional heat redistribution by topographically driven ground water flow. Thus, the surface heat flow is not expected to bear a signal of deeper lithospheric thermal anomalies that can be separated from heat flow typical for orogenically altered crust (40–70 mW/m 2). The new insights on the geothermal signature in the Baikal rift once more show that continental rifting is not by default characterized by high heat flow.

A NEW HEIGHT REFERENCE NETWORK IN TAIWAN

The island of Taiwan is located in an active tectonic zone on the boundary of the Eurasian and Philippine Sea plates. Due to the continuous mountain building process in association with the collision of the two plates, it is very important for Taiwan to periodically re-survey the island so as to maintain the intrinsic accuracy requirement of its vertical reference network. The existing height network was created in 1979 by means of the spirit levelling technique with theoretical surface gravity quantities derived from the Geodetic Reference System 1967 (GRS67) normal gravity field. Because of the lack of use of actual gravity measurements in its creation, the existing network has been found to suffer from severe systematic errors in the central mountainous areas.In this paper, we present the design and implementation of a new national vertical datum in Taiwan, Taiwan Vertical Datum 2001 (TWVD2001). The new datum was developed by optimally combining geodetic levelling and surface gravity observations collected at 1010 newly established benchmarks within a network of 2200-km first-order levelling lines. The data analyses and adjustment computation were based on geopotential numbers. Both orthometric and normal heights were computed for the new vertical reference network.

A study of the tectonically active Marmara region, Turkey, using a global positioning system (GPS)

The Marmara region is an active tectonic zone characterized by a transition in the dextral strike-slip regime of the western part of the North Anatolian Fault Zone. The main goal of this paper is to assess the use of global positioning system (GPS) data sets collected during five relatively short time intervals during the period December 2000 – March 2002 to detect potential crustal deformations. To determine if the deformations measured with GPS are real or only a data artifact, a statistical reliability analysis of the solutions is performed. The results indicate that each station has statistically different temporal behavior and significant relative motions. This area is consequently still very active, with significant deformation patterns. Although the average magnitude for our estimated displacement rates with respect to ANKR station, which represents the rigid motion of the Anatolian plate, is in the order of 1.1 cm/year in the south of the North Anatolian Fault, it increases to 2.3 cm/year in the northern part of the area.

Earthquakes distribution and their focal mechanism in correlation with the active tectonic zones of Romania

On the basis of an earthquake catalogue covering the time interval from 1929 to 1997 and comprising fault plane solutions, we analyze the distribution of the seismic activity on the Romanian territory in connection with the seismogenic zones, previously defined, and available geological and tectonic information. At the same time, the stress field characteristics, deduced from the available fault plane solutions, are investigated for different depth intervals. Predominant clusterings of the principal deformation axes and rupture plane orientation are observed in the Vrancea subcrustal domain in contrast with the earthquakes in the crust, which show no clear trending in the stress field. A number of 526 events occurred in the period 1929–1997 and having the magnitude 1.5< M S <7.4 are analyzed according to their fault plane solutions. The relatively large number of events provides important and reliable information to redefine from seismological point of view the limits of the seismogenic and active zones.

Basic characteristics of active tectonics of China

During the last 20 years, studies on active tectonics in China have entered a new quantitative research stage and made a great progress. Summing up the quantitative results, a Map of Active Tectonics of China on the scale of 1︰4 million has been compiled. In the map all types of active tectonics and their kinematic parameters are reflected in possible detail, such as active faults, active folds, active basins, active blocks, volcanoes, and earthquakes. This paper summarizes the basic characteristics of active tectonics of China. The Himalaya Mountains and Taiwan Island are major plate boundaries where the slip rates are larger than 15 mm/a. Tectonic activity in the continental intraplate region is characterized by block motion. The crust and lithosphere in the region were dissected into blocks with different orders. Of them the Qinghai-Xizang (Tibet), Xin- jiang, and North China block regions exhibit the most recent tectonic activity. The kinematic characteristics of more than 200 active tectonic zones indicate that the intraplate tectonic activity represents a block motion at a limited low rate. Horizontal slip rate along the tectonic boundary belts between the blocks is generally less than 10 mm/a, and 10—15 mm/a in maximum, and hence it does not support the continental escape theory of high rate of slip.