Earthquake in central Italy and velocities structure of the mantle

T. A. Tsvetkova, I. V. Bugaenko, L. N. Zaets

Abstract


A three-dimensional P-velocity model of the European mantle built on the Taylor approximation made it possible to analyze the velocity structure of the mantle under the Mediterranean and, in particular, under Central Italy, to a depth of 2500 km.

It is shown that the crust earthquakes in Central Italy, characterized by a magnitude up to 7,0, are associated with super-deep fluid processes of the mantle. A possible seismic channel was found, linking the propagation of the fluid process from the lower mantle to the crust inclusive. The manifestations of the super-deep fluid process are isolated at the depths of the lower and middle mantle. In the upper mantle and transition zone of the upper mantle, the channel is determined by the distinguished seismic boundaries of the 2th-generation, which are determined by the transition from the increase of gradients of velocity from depth to descent or vice versa. These seismic boundaries correspond to phase transitions.

Consideration of the deep structure of the mantle under Central Italy has shown the presence of low velocities in the area under consideration from the lower mantle to the zone of division-2. The analysis of the structure of tops of the upper mantle showed the presence of the mantle section in area of 13°±0,5 lon.Ч43°±0,5 lat., where the earthquakes with a magnitude up to 7,0 stand out in the crust. A section is timed to the area of thrust Moho boundary of and correlated with its crossing of Ankona-Ancio fault, dissociating the Central Apennines from the North. This region corresponds to a triple intersection of faults and an increased heat flux, and there is also an increased fission of the upper mantle (7 seismic boundaries of the 2th-generation). Depth of occurrence of the main geodynamic boundary is less than 670 km.


Keywords


Velocities structure of the mantle; earthquake; Central Italy; seismic tomography; super-deep fluids; seismic boundaries

References


Bugaenko I. V., Shumlyanskaya L. A., Zaets L. N., Tsvetkova T. A., 2012. Three-dimensional P-velocity model of the upper mantle of the Western Mediterranean. Geofizicheskiy zhurnal 34(1), 14—31 (in Russian).

Geyko V. S., Bugaenko I. V., Shumlyanskaya L. A., Zaets L. N., Tsvetkova T. A., 2007. 3D P-velocity structure of the upper mantle of the Eastern Mediterranean. Geofizicheskiy zhurnal 29(4), 13—30 (in Russian).

Gusev G. A., Gufeld I. L., 2006. The Seismic Process in a Geologic Medium of Extreme Energy Saturation and Earthquake Prediction. Vulkanologiya i seycmologiya (6), 71—78 (in Russian).

Gufeld I. L., 2013. On deep degassing and structure of the lithosphere and upper mantle. Elektronnyy zhurnal «Glubinnaya neft» 1(1), 18—44 (in Russian).

Gufeld I. L., 2007. Seismic process. Physico-chemical aspects. Korolev: TsNIIMash Publ., 160 p. (in Russian).

Dobretsov N. L., 2010. Global geodynamic evolution of the Earth and global geodynamic models of the Earth. Geologiya i geofizika 51(6), 761—784 (in Russian).

Zharkov V. N., 1983. Internal structure of the Earth and planets. Moscow: Nauka, 416 p. (in Russian).

Letnikov F. A., 2003. Ultra-deep fluid systems of the Earth. Doklady RAN 390(5), 673—675 (in Russian).

Lobkovskiy L. I., Nikishin A. M., Khain V. E., 2004. Modern problems geotectonics and geodynamics. Moscow: Nauchnyy mir, 610 p. (in Russian).

Petrova A. A., Petrishchev M. S., 2011. Fluid systems of the Mediterranean. Vestnik KRAUNTS. Nauki o zemle (1), 23—33 (in Russian).

Puzyrev N. N., 1997. Methods and objects of seismic research. Introduction to general seismology. Novosibirsk: SIC OIGGM, 301 p. (in Russian).

Pushcharovskiy Yu. M., Pushcharovskiy D. Yu., 2010. Geology of the Earth’s Mantle. Moscow: Geos, 138 p. (in Russian).

Rebetskiy Yu. L., Ovcharenko O. O., Savvichev P. A., 2014. Field of current stresses of the crust of South-Western Europe and the Mediterranean. Vestnik KRAUNTS. Nauki o zemle (2), 68—84 (in Russian).

Rodkin M. V., Nikitin A. N., Vasin R. N., 2009. Seismotectonic effects of solid-phase transformations in geomaterials. Moscow: Geos, 198 p. (in Russian).

Modern geodynamics and geophysical fields of the Carpathians and adjoining territories, 2015. Eds. K. R. Tretiak, V. Yu. Maksymchuk, R. I. Kutas. Lviv: Lvivska politekhnyka, 418 p. (in Ukrainian).

Starostenko V. I., Kendzera A. V., Bugaenko I. V., Tsvetkova T. A., 2011. The earthquake in L’Aquila and the features of the three-dimensional P-velocity structure of the mantle beneath the Adriatic plate and its surroundings. Geofizicheskiy zhurnal 33(4), 62—73 (in Russian).

Khain V. E., 2001. Tectonics of continents and oceans. Moscow: Nauchnyy Mir, 604 p. (in Russian).

Khain V. E., Lomidze M. G., 2005. Geotectonics with the basics of geodynamics. Moscow: Knizhnyy mir, 559 p. (in Russian).

Shevchenko V. I., Lukk A. A., Prilepin M. T., Reilinger R. E., 2014. Modern geodynamics of the Mediterranean Little Caucasian part of the Alpine-Indonesian mobile belt. Fizika Zemli (1), 40—59 (in Russian). doi: 10.7868/S0002333713060136.

Antonioli A., Piccinini D., Chiaraluce L., Cocco M., 2005. Fluid flow and seismicity pattern: Evidence from the 1997 Umbria-Marche (central Italy) seismic sequence. Geophys. Res. Lett. 32, L10311. doi.org/10.1029/2004GL022256.

Agosta F., Kirschner D. L., 2003. Fluid conduits in carbonate-hosted seismogenic normal faults of central Italy. J. Geophys. Res. 108(B4), 2221. doi: 10.1029/2002JB002013.

Bijwaard H., Spakman W., Engdahl E. R., 1998. Closing the gap between regional and global travel time tomography. J. Geophys. Res. 103(B12), 30055—30078. doi: 10.1029/98JB02467.

Boschi L., Faccenna C., Becker T. W., 2010. Mantle structure and dynamic topography in the Mediterranean. Geophys. Res. Lett. 37, L20303. doi:10.1029/2010gl045001.

Cassinis R., Scarascia S., Lozej A., 2003. The deep crustal structure of Italy and surrounding area from seismic refraction data. A new synthesis. Bоll. Soc. Geol. It. 122, 365—376.

Ciaccio M., Barchi M. R., Chiiarabba C., Msrabella F., Stucci E., 2005. Seismological, geological and geophysical constraints for the Gualdo Tadino fault, Umbria-Marche Apennines (Central Italy). Tectonophysics 406(3/4), 233—247.

Forte A. M., Mitrovica J. X., 2001. Deep-mantle high-viscosity flow and thermochemical structure inferred from seismic and geodynamic data. Nature 410, 1049—1056. doi:10.1038/35074000.

Fry B., Boschi L., Ekstrцm G., Giardini D., 2008. Europe-Mediterranean tomography: High correlation between new seismic data and independent geophysical observables. Geophys. Res. Lett. 35(4), L04301.doi: 10.1029/2007GL031519.

Geyko V. S., 2004. A general theory of the seismic travel-time tomography. Geofizicheskiy zhurnal 26(2), 3—32.

Gualtieri L., Serretti P., Morelli A., 2014. Finite-difference P wave travel time seismic tomography of the crust and uppermost mantle in the Italian region. Geochem. Geophys. Geosyst. 15(1), 69—88.

International Seismological Centre, 2017. [электронный ресурс]. http://www.isc.ac.uk

Koulakov I., Kaban M. K., Tesauro M., Cloetingh S., 2009. P- and S-velocity anomalies in the upper mantle beneath Europe from tomographic inversion of ISC data. Geophys. J. Int. 179(2), 345—366. doi: 10.1111/j.1365-246X.2009.04279.x.

Luccio F., Ventura G., Giovambattista R., Piscini A., Cinti F., 2010. Normal faults and thrusts reactivated by deep fluids: The 6 April 2009 M w 6.3 L’Aquila earthquake, central Italy. J. Geophys. Res. 115, B06315. doi:10.1029/2009jb007190.

Marone F., Van der Lee S., Giardini D., 2004. Three-dimensional upper-mantle S-velocity model for the Eurasia-Africa plate boundary region. Geophys. J. Int. 158(1), 109—130. https://doi.org/10.1111/j.1365-246X.2004.02305.x.

Piroddi L., Ranieri G., Freund F., Trogu A., 2014. Geology, tectonics and topography underlined by L’Aquila earthquake TIR precursors. Geophys. J. Int. 197(3), 1532—1536. https://doi.org/10.1093/gji/ggu123.

Piromallo C., Morelli A., 2003. P wave tomography of the mantle under the Alpine-Mediterranean area. J. Geophys. Res. 108(B2), 2065. doi: 10.1029/2002JB001757.

Scafidi D., Solarino S., 2012. Can local earthquake tomography settle the matter about subduction in the Northern and Central Apennines? Response from a new high resolution P velocity and Vp/Vs ratio 3D model. Tectonophysics 554-557, 63—73. doi: 10.1016/j.tecto.2012.06.007.

Scuderi M., Collettini C., 2016. The role of fluid pressure in induced vs. triggered seismicity: insights from rock deformation experiments on carbonates. Sci. Rep. 6, 24852. doi: 10.1038/srep24852.

Soldati M., Marchetti M. (eds.), 2017. Landscapes and Landforms of Italy. Springer Int. Publ. 539 p. doi: 10.1007/978-3-319-26194-2

Spakman W., Van der Lee S., Van der Hilst R. D., 1993. Travel-time tomography of the European-Mediterranean mantle down to 1400 km. Phys. Earth Planet. Int. 79(1-2), 3—74. doi: 10.1016/0031-9201(93)90142-V.




DOI: https://doi.org/10.24028/gzh.0203-3100.v40i2.2018.128929

Refbacks

  • There are currently no refbacks.