European Geosciences Union Strain field on the Sicily-Calabria (Southern Italy) from seismic and geodetic data General Assembly 2011 Strain field on the Sicily-Calabria (Southern Italy) from seismic and geodetic data Vienna, Austria, 03 – 08 April 2011 (1) Università di Catania, Dipartimento di Scienze Geologiche, C.so Italia 55, 95127 Catania, Italy
(2) Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Catania, P.zza Roma 2, 95123 Catania, Italy TS6.1/G3.3/GD5.4/SM1.5 EGU2011-10640 - Hall XL, No. XL303 AngelicaAngelica C.C.(1)(1),, BonforteBonforte A.A.(2)(2),, DistefanoDistefano G.G.(1)(1),, SerpelloniSerpelloni EE (3)(3) andand PuglisiPuglisi G.G.(2)(1) Wednesday, 06 April 2011 (3) Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Bologna, via D. Creti 12, 40128 Bologna, Italy [email protected] [email protected]
FOCAL MECHANISM OF EARTHQUKES SEISMICITY Abstract GEODINAMIC FRAMEWORK GEODETIC VELOCITY - MEASURED 11˚ 12˚ 13˚ 14˚ 15˚ 16˚ 17˚ 18˚ The kinematics and geodynamics of the Sicilian-Calabrian subduction system is still 40˚ CUCC 40˚ matter of debate, mainly due to ambiguities which constrain the motion of Sicily and the Ionian Sea in the framework of the slow convergence of the Nubia-Eurasia CETR PIPA plate. The rapid increase of continuous GPS stations in the studied area, together TVRNLUZZ ARCA CAMO CRLM CARO CCRI with new integration of GPS surveys carried out from early 90s, is going to add new COSE STSV
25/04/1836 fundamental constraints to the comprehension of this complex region, both in terms SERS 14/07/1767 39˚ 39˚ 04/10/1870 Sila of plate kinematics and elastic strain accumulation across active faults, responsible Adrian micr STROSVIN 27/03/1638 USTIUSIX PANA for some of the largest earthquakes of the entire Mediterranean area. POROJOPP IFIL CALABRIA IACL 08/03/1832 LOSV PLAC VCSP GIOI
MILA MSRUSPURPACECELL Tyrrhenian sea AREN SCRI 01/03/1783 Introduction MESAMESS INGM 08/09/1905 CAPO APOS TGRC M = 7.0 05/11/1659 SPLA MILO Capo 38˚ MARE GBLM 38˚ e FAVI MMME9518 MPAZ oplate CORL Vaticano07/02/1783 9520 9532TAOR Serr The complex dynamics of the Mediterranean is the result of the collision (still ongoing) 05/02/1783 GALF between Eurasian plate and Nubian plate. This has led to the formation of different tectonic RESU 9510 16/11/1894 ECNV 06/09/2002 06/02/1783 ENNA M = 6.0 omonte systems as chains, marginal retroarch basins and subduction areas. In this context, Sicily Aspr IAZZ 15/01/1940 28/12/1908 IRNEIP06ISCP M = 5.4 15/04/1978 M = 7.1 IM02 ISLIIGAIP09T 01/09/1726 and Calabria, are the natural connection between the Appennine chain and the African chain. HCRLHAGAIP10 Continuous GPS Stations M = 6.1 ICDRIPNC ICRC 05/03/1823 RAFF IP12 HVZN Mti. Nebrodi M.ti Peloritani SSYXIP18 IP19 5.00 mm/yr In particular, we find the following structural complex: Aeolian volcanic arch, Calabrian arch, IP21 M.ti Madonie 19/07/1868 37˚ HMDC HAVL 37˚ M.te Etna 15/10/1911 M = 5.8 Northern chain, Etna volcano and Hyblean plateau. We easily deduce, from this, that the two 15/01/1968 NOT1NOTO M = 6.1 08/03/1959 M = 5.2 PZIN Belice Valley SICILIA Catania 20/02/1818 regions (Sicily and Calabria) are the key areas for investigating this very complex dynamics. Epoch GPS Stations 361 d. C. plain 5.00 mm/yr 04/02/1169? 04/02/1169 Beach ball (red and white): CMT catalogue 11/01/1693? 11/01/1693 Ionian sea 09/01/1693? 11/01/1848 S C R Z Eurasian Plate Beach ball (blue and white) : RCMT catalogue 13/12/1990 10/12/1542 M = 5.4 Error Ellipse Mti. Iblei Strong historical earthquakes 36˚ 36˚ Sicily channel 09/01/1693? Instrumental earthquakes PRINCIPAL TECTONIC STRUCTURES 11˚ 12˚ 13˚ 14˚ 15˚ 16˚ 17˚ 18˚ ?Hypothetical epicenter SCRZ: Siculo calabrian rift zone
Inversion of seismic and geodetic data Nubian Plate Z Historical and instrumental earthquakes EPICENTERS DISTRIBUTION In this work we calculate the strain-rate field of the Southern part of Italy, by combining seismic and geodetic (GPS) data. 8˚E 10˚E 12˚E 14˚E 16˚E 18˚E 20˚E Extension The seismicity of Siciliy and Calabria, is concentrated in two well-defined zones: SCRZ For the seismic strain processing, we used earthquake focal solutions from the CMT catalogue, for earthquakes with (Sicilian Calabrian Rift Zone) and Northern Sicily. The SCRZ is characterized, as a whole, Compression M>5, and from the RCMT catalogue, for earthquakes with 4.5 Calabrian seismic belt includes the strongest earthquakes which have occurred in Capo e area and the stations (EGPS) which are periodically surveyed, belonging to denser networks lying on the Iblean Vaticano Southern Italy in the last six centuries: the 1693 earthquakes (Eastern Sicily), the 1783 -40 Serr plateau (Bonforte et al., 2002) and across the Messina Straits (Serpelloni et al., 2010). We used GPS station Calabrian sequence earthquake, the Monteleone earthquake of 1905 and the Messina Aeolian Islands C velocities obtained by means of GAMIT/GLOBK processing package. Taking into account the network geometry and -80 earthquake of 1908. Instead, Northern Sicily was concerned by events with Mmax~6.1; 38˚N 38˚N omonte the estimated velocity at each site, the horizontal strain-rate field has been calculated, applying the methods of T indari-Letojanni Fault the earthquakes of the Northern Sicilian coast, the 1968 earthquake of the Belice valley -120 Aspr Haines and Holt (1993). CGPS networks provide precise regional constraints on plate kinematics, the local periodic Mti. Nebrodi Mti.Peloritani ch Mti. Madonie Ar and the 2002 earthquake of the Southern Tyrrhenian sea. -200 networks, add fundamental information to constrain the rates of strain loading across major active fault systems, Maghrebian Thrust Belt Mte.Etna Calabrian due to their high spatial density. -400 Belice Valley Catania S -600 SICILIA plain 36˚N 36˚N Hyblean-Maltese Escarpment ont -800 Thrust fr Ionian sea Scordia-Lentini Graben o-Sortino Fault GEODETIC STRAIN km GEODETIC VELOCITY - CALCULATED SEISMIC STRAIN Grammichele-Montelaur 0 87.5 175 SCRZ: Siculo - Calabrian rift zone Mti. Iblei Sicily channel A.-Pedagaggi Line Normal Fault 8˚E 10˚E 12˚E 14˚E 16˚E 18˚E 20˚E Avola Fault 11˚ 12˚ 13˚ 14˚ 15˚ 16˚ 17˚ 18˚ 19˚ 11˚ 12˚ 13˚ 14˚ 15˚ 16˚ 17˚ 18˚ 19˚ osso Magnitudo 3 4 5 6 Pantelleria Rift Strike-slip fault ( dashed when the alleged ) DataDa: 1999/01/01A: 2011/03/22 40˚ 40˚ 40˚ 40˚ LatitudineMin: 35.0Max: 41.0 Scicli-Ragusa-Monter LongitudineMin: 7.0Max: 21.0 MagnitudoMin: 3.0Max: 10.0Tipo: Mag pref Profondità(km)Min: NDMax: ND Terremoti totali: 659 2011 Mar 22 13:13:21 INGV, Centro Nazionale Terremoti, Centro Dati e Informazione sui Terremoti GEODETIC STRAIN AND PRINCIPAL SEISMOTECTONIC STRUCTURE 39˚ 39˚ 39˚ 39˚ Epicentral distribution and CMT-RCMT seismic catalogs 12˚ 13˚ 14˚ 15˚ 16˚ 17˚ Conclusions 39˚ 39˚ 01/03/1783 05/11/1659 The figure above shows the instrumental seismicity, also full of events of small 08/09/1905 M = 7.0 The inversion of both datasets provides the seismic and magnitude. It is interesting to note how the seismicity is distributed along the 07/02/1783 geodetic strain fields over Italy. It evidences the areas main tectonic systems of the area: Northern Sicily, Aeolian Islands, Calabrian 05/02/1783 affected by a mainly extensional regime and those where the 38˚ 38˚ 38˚ 38˚ Arch and Hyblean Plateau. For the entire area of interest, the seismicity can be 06/09/2001 M =6.6 16/11/1894 06/02/1783 compressive strain, induced by the continental collision, is still considered shallow, less than 50 km of depth, with the exception of the area 15/04/1978 M = 6.1 15/01/1940 M = 5.4 28/12/1908 M = 7.1 that runs from the basin of the Calabrian Ionian offshore where there is a 01/09/1726 active. seismic deep, in response to subduction of oceanic crust. 38˚ 05/03/1823 38˚ At large scale, results show active N-S oriented compressive Dziewonski and seismology group at Harward Univesity, determine and catalog strain regime in Northern Sicily, while the Southern 15/01/1968 M =6.1 37˚ 37˚ 37˚ 37˚ parameters of seismic sources since 1997 for erathquakes with M > 5; this 361 d.C. Appennines and Eastern Sicily are clearly affected by an catalog, provides important information on the geometry and orientation of extensional strain regime. 04/02/1169? seismogenic structures, but not on long-term seismic deformation. Therefore, 04/02/1169? 11/01/1693? 11/01/1693? In particular, looking at the map on the left, we remark how to complete the study of the deformation zone, we must also consider the 09/01/1693? EXTENSION 13/12/1990 M = 5.4 Calabria and Sicily are confirmed as the Mediterranean region Extension catalog RCMT (Regional Centroid Moment Tensor). Earthquakes of this catalog 36˚ 36˚ 36˚ 36˚ 37˚ 37˚ with the major seismic hazard. In fact, the geodetic data show (4.5