Tectono-Thermal Evolution of the Red Sea Rift

The Oligocene-Recent Red Sea rift is one of the preeminent examples of lithospheric rupture in the recent geological past, forming the basis for many models of how continental breakup occurs and progresses to the formation of new oceanic crust. Utilisation of low-temperature thermochronology in the Red Sea Rift since the 1980s has been key to constraining its spatio-temporal evolution, providing constraints for the propagation of strain and geomorphological development of its margins where datable syn-tectonic strata and/or markers are absent. We review the wealth of published apatite fission track and (U-Th-Sm)/He data from along the Red Sea, affording insights into the Oligocene-Recent thermo-tectonic evolution of the Nubian and Arabian margins. A regional interpolation protocol was employed to synthesise time-temperature reconstructions generated from the mined thermochronology data and burial histories produced from vitrinite reflectance and well data. These cooling-heating maps record a series of pronounced episodes of upper crustal thermal flux related to the development of the Oligocene-Recent Red Sea Rift. Assimilation of these regional thermal history maps with paleogeographic reconstructions and regional magmatic and strain histories provide regional perspectives on the roles of tectonism and geodynamic activity in Red Sea formation and their effects on rift margin development.

Comparative Analysis of Statistical and Analytical Techniques for the Study of GNSS Geodetic Time Series

GNSS systems allow precise resolution of the geodetic positioning problem through advanced techniques of GNSS observation processing (PPP or relative positioning). Current instrumentation and communications capabilities allow obtaining geocentric and topocentric geodetic high frequencies time series, whose analysis provides knowledge of the tectonic or volcanic geodynamic activity of a region. In this work, the GNSS time series study was carried out through the use and adaptation of R packets to determine their behavior, obtaining displacement velocities, noise levels, precursors in the time series, anomalous episodes, and their temporal forecast. Statistical and analytical methods were studied, for example, ARMA, ARIMA models, least-squares methods, wavelet functions, and Kalman techniques. To carry out a comparative analysis of these techniques and methods, significant GNSS time series obtained in geodynamically active regions (tectonic and/or volcanic) were considered.

An integrated approach to assessing the geodynamic activity of the Earth's crust in the low seismic East Baltic region

<p>The East Baltic region (EBR), located on the ancient Precambrian East European Craton, is characterized by low seismic and deformational activity. The EBR is located at a distance of about 2000 km from the divergent zone in the North Atlantic and from the convergent zone in the Mediterranean Sea.</p><p>Nevertheless, historical and modern earthquakes have occurred in the EBR. Historical earthquakes occurred in 1616 (<em>Bauska</em>, Latvia, VI), 1670 (<em>Pärnu</em>, Estonia, VI), 1821 (<em>Koknese</em>, Latvia, VI), 1823 (<em>Võrtsjärv</em>, Estonia, VI), 1857 (<em>Irbe</em>, Latvia, VI), 1896 (<em>Jelgava</em>, Latvia, V), and modern earthquakes occurred on 10/25/1976 (<em>Osmussaar</em>, Estonia, M 4.7), 09/21/2004 (<em>Kaliningrad</em> region, Russia, Mw 5.2).</p><p>The study of slow (tectonic creep) and fast (earthquakes) deformations is practical importance in EBR for safety of energy facilities - <em>Plavinas</em> HPP, <em>Baltic</em> (Kaliningrad region of Russia) NPP and <em>Ostrovets</em> (Belarus) NPP.</p><p>In the central part of the territory of Latvia, signs of geodynamic activity of the Earth's crust have been identified. A characteristic feature is the trans-regional <em>Olaine-Inčukalns</em> tectonic fault, which crosses the Riga agglomeration. The fault is traced in the <em>Caledonian</em> structural complex.</p><p>Previous studies on seismic hazard assessment in Latvia (Safronovs & Nikulins, 1999; Nikulins, 2011) were based on combination of seismic, geophysical, geodetic and geological data. These studies made it possible to assess the seismotectonic potential of the Earth's crust, parameters of seismogenic zones and to state a very low seismic activity.</p><p>A sparse seismic network and poor seismic-geological conditions affect the effectiveness of seismological monitoring in EBR. To understand of driving mechanisms for earthquakes, results of remote sensing (<em>Persistent Scatterer Interferometry - PSI</em>) of surface (1992 - 2000), studies of radon anomalies (2014), and macroseismic data (2010) were used.</p><p><em>PSI</em> method made it possible to reveal the anomalous vertical velocity (25.4 mm/year) of opposite sides of fault, adjacent to the <em>Olaine-Inčukalns</em> fault in the southwest of Riga. The average vertical velocity does not exceed 1.03 mm/year. The study of the radon field in northeast of the <em>Olaine-Inčukalns</em> fault revealed an intense (140000 Bq/m<sup>3</sup>) radon anomaly (Nikulins, 2014).</p><p>In addition, on 22.11.2010, population of Riga and its environs felt shaking. Mechanism of the <em>Olaine-Inčukalns</em> fault is predominately <em>thrust faulting</em> with a <em>strike-slip</em> component, whereas mechanisms of most other faults in Latvia are <em>normal faulting</em> type.</p><p>These signs indicate the activation of the <em>Olaine-Inčukalns</em> tectonic fault. Thus, on the EBR, under conditions of slow deformation of the Earth's crust, a comprehensive analysis of various geological, geophysical and deformation parameters has justified itself.<br><br></p><p>Literature</p><p>Nikulins V., 2014. <em>Geodynamic Hazard Factors of Latvia: Experimental data and Computational Analysis</em>. Baltic Journal of Modern Computing, 7 (1), 151 – 170.</p><p>Safronovs O.N., Nikulins V.G., 1999. <em>General seismic zoning of Latvia</em>. Latvian geology news, 6, 30 - 35. (In Latvian).</p><p>Nikulin V., 2011. <em>Assessment of the seismic hazard in Latvia. Version of 2007 year</em>. RTU science articles. Materials Science and Applied Chemistry, 1 (24), 110 – 115.</p>

The Seismotectonic Significance of Geofluids in Italy

There is growing interest in how geofluid emissions are released in the atmosphere by the planet’s geodynamic activity, and how much they contribute to the global budget of greenhouse gases. Many workers are addressing this issue with studies conducted at global scale, so as to get the required global-scale answers. The data available at the global scale on geofluids, faults, earthquakes and volcanoes, however, are generally too coarse to provide these answers. We investigate the relationships between geofluid emissions and tectonics at a more detailed scale. Building on over a century of data on geofluid emissions and on an extensive knowledge of the region’s tectonics and seismicity, we focused on Italy, one of the areas of the globe that experience the largest release of natural CO2 and CH4. We systematically overlaid and compared data collected by a number of workers into 13 published countrywide databases concerning geofluid emissions, carbon-bearing deposits, seismogenic faults, historical and instrumentally documented earthquakes, and heat flow observations. Our results indicate that 1) thermal springs and CO2 emissions dominate in areas of mantle upwelling and crustal stretching, but also that 2) some of them occur in the extending inner Apennines, generally along major lithospheric chain-perpendicular lineaments that bound the largest normal faults. Conversely, 3) CH4 emissions and mud volcanoes dominate in areas undergoing active contraction, where no CO2 emissions are observed; in particular, we find 4) that mud volcanoes concentrate where the crests of active anticlines intersect major lithospheric chain-perpendicular lineaments. An overarching conclusion is that, in Italy, the release of geofluids is primarily controlled by deep crustal discontinuities that developed over the course of 5–10 My, and is only mildly affected by ongoing crustal strains. Geofluid emissions bring information on processes that occur primarily in the lower crust, marking the surface projection of generally hidden discontinuities that control the geometry and modes of seismic release. As such they may also provide valuable insight for improving the assessment of seismic hazard in hard-to-investigate seismically active regions, such as Italy.

Geoactive Zones and the Structure of Plant Communities in Connection With New Discoveries in Space Geology

The purpose of the work is to find out how plants react to such zones and whether their phytoindication is possible. Two territories of the Perm territory were studied: the Vishersky Nature Reserve and forests near Perm. The research methodology included lineament and geostructurometric analysis of space images and special maps using ring structures discovered on the Earth’s surface by Yu. I. Fivenskii, as well as phyto- and bioindication of small geoactive zones. It was found that in the forests near Perm favorable zones of such zones occupy 1.44% of the territory and within their limits the safety of common pine (Pinus sylvestris L.) is 29–42 times higher. Phytoindication of small geoactive zones of 1.0 and 3.0 m by common pine was shown in the zones of influence of these zones: 0–18 cm — the radius of inhibition with the absence of trees; 19–29 cm — the depression zone with small trees; 30–48 cm — the comfort zone with medium and large trees. Two types of networks formed by zones of 1.0 and 8.0 m in size near Perm (on the plain) and in the reserve (in the mountains) were compared. In the mountains, with high geodynamic activity of territories, the networks are oriented in one direction, while on the plain their orientation is misaligned by 30°. In the reserve, large trees of Siberian spruce (Picea obovata Ledeb.) were located on small geoactive zones of 1.0 and 8.0 m, and trees of Siberian pine (Pinus sibirica Du Tour) — on zones 1.0 and 3.0 m in combination with zones 16, 32 and 55 m. In the subgolets zone, ring structures of perennial plants were also found on the first two types of zones. In addition, along the edges of the swamps, chains of trees were found whose direction coincides with ring faults, and the chains themselves are similar to the structure of small geoactive zones networks, and this fractality requires field verification. The hypothesis recharge of plants within geoactive zones is proposed, which also explains the successful growth of trees on rocks, where the amount of available soil is minimal.

THE EXPERIENCE OF PLUGGING A MINE SHAFT UNDER CONDITIONS OF MANIFESTATION OF MODERN GEODYNAMIC ACTIVITY

The paper presents the results of studying of the effectiveness of water pressure in the shaft of a mine with the use of grouting are presented. The enclosing rock massif is character-ized by simple hydrogeological conditions and moderate manifestation of modern geodynamic activity. Despite the significant volume of the performed backfill measures, the expected result was not obtained due to the underestimation of modern geodynamic processes when choosing the backfill materials. In the conditions of a geodynamically active rock mass, the plugging ma-terial must retain plasticity throughout the entire period of operation.