Gutenberg Richter

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    SIXTH FRAMEWORK PROGRAMME PRIORITY FP6-2002-INCO-MPC-1

    EARTHQUAKE PROTECTION OF HISTORICAL BUILDINGS BY REVERSIBLE MIXED TECHNOLOGIES

    Instrument: Specific Targeted Research Project Thematic Priority: FP6-2002-INCO-MPC-1 Start date of project: 1st October 2004 Duration: 36 months

    Contribution of UTCB to the Workpackage 3

    RISK ANALYSIS Date of preparation: August 5, 2005 Author(s): Dan Lungu, Cristian Arion, Radu Vacareanu Organisation: Technical University of Civil Engineering Bucharest,

    Structural Safety & Natural Hazards Research Centre WP Leader: Organisation: Project coordinator: Federico M. Mazzolani Organisation: Department of Structural Analysis and Design,

    University of Naples Federico II, Italy

    Revision [draft]

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    SIXTH FRAMEWORK PROGRAMME PRIORITY FP6-2002-INCO-MPC-1

    1. Seismic Hazard of Romania Seismic zones of Romania are given in the map of Figure 1 according to simplified original classification of Dr. Cornelius Radu.

    Figure 1. Seismic zones of Romania end the epicenters of earthquakes during the period 984 - 2001

    The map of maximum observed seismic intensities in Romania for a time interval ranging from 1091 to 1980 is presented in Figure 2. According the map, the maximum seismic intensity observed in Bucharest over almost one thousand years is VIII+.

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    SIXTH FRAMEWORK PROGRAMME PRIORITY FP6-2002-INCO-MPC-1

    Figure 2. Map of maximum observed seismic intensities in Romania, 1091-1980

    In Figure 3 is illustrated the present seismic zonation of Romania, Bulgaria, Ukraine and

    Republic of Moldova. The general pattern of the map (which is based on deterministic macroseismic observations) as well as the content of the table describing the conversion of seismic intensity into ground acceleration are self-explanatory. They clearly suggest the need for harmonization of seismic macrozonation maps and prove the need for a joint zonation of the seismic hazard in the influence area of the Vrancea source. A NATO project with this subject is under way.

    Figure 3. Macroseismic zonation for Vrancea source

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    SIXTH FRAMEWORK PROGRAMME PRIORITY FP6-2002-INCO-MPC-1

    Figure 4. Present seismic zonation (2005) of Romania corresponding with MRI=50 yr. Two catalogues of earthquakes occurred on the territory of Romania were compiled,

    more or less independently, by Radu (1974, 1980, 1995) and by Constantinescu & Marza (1980, 1995). The Radus catalogue is more complete, even the majority of significant events are also included in the Constantinescu & Marza catalogue. The magnitude in Radu catalogue is the Gutenberg-Richter magnitude, MGR (Gutenberg & Richter, 1954). Table 1. Radu Catalogue of major historical Vrancea earthquakes, I0 9 (in Design of structures in seismic zones: Eurocode 8 - Worked examples, 1997)

    Nr.

    Date Time (GMT)

    Intensity (max) Io

    Magnitude MG-R MS

    Radus source

    h:m:s Radu Others Radu Others 1 1196 Feb 13 07: (8) 8-9 9/CM (6.7) 7.2 7.3/CM 7.0/KS RT, R 2 1230 May 10 07: (8-9) 9+ 8.5/CM (6.9)7.4 7.1/CM 7.1/KS RT, R, N3 1446 Oct 10 04: 8 8.5/CM 8-9/RT 6.7 7.3/CM 7.3/KS 6.9/RT RT, R 4 1471 Aug 29 10-11: (8) 9 9/CM 8-9 KS (6.9) 7.4 7.3/CM 7.1/KS RT, R 5 1516 Nov 8 12: 9 9/CM 8/KS 7.2 6.8/KS RT, R 6 1620 Nov 8 13-14: (8-9)9 9/CM 8/KS (6.9)7.2 7.3/CM 6.5/KS RT 7 1679 Ian29?/Aug 9 (8) 6 9/CM (6.7) 5.5 7.3/CM 6.8/KS RT 8 1681 Aug 18 (00)01: 9 8/CM (6.7)7.4 6.8/CM 6.8/KS RT 9 1738 May 31/ Jun 11 10-11: (8-9) 9 9.5/CM (6.9)7.4 7.5/CM 7.0/KS RT, R 10 1802 Oct 26 10:55 9 10/CM 7.5 7.7/CM 7.4/KS R 11 1838 Jan 23 18:45 8 9/CM 6.7 7.3/CM 6.9/KS R

    Observations: (i) Abbreviations of Radus sources:R - Radu Catalogues, 1971 & 1974, RT - Radu & Torro Catalogue, 1986, N - Nikonov Catalogue, CM - Constantinescu & Marza Catalogue, 1980, KS - Kondorskaya & Shebalin Catalogue, 1977 (ii) Radus initial (1980) estimation of intensity and magnitude are given in parenthesis (...); (iii) Radus underlined values for I0 intensities denote the most probable value; (iv) I0 is maximum MSK-64 intensity.

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    SIXTH FRAMEWORK PROGRAMME PRIORITY FP6-2002-INCO-MPC-1

    Table 2. Catalogue of major historical crustal (surface) earthquakes in Romania

    IoIntensity (MSK)

    MG-R

    Mw Moment

    Magnitude

    Date Lat.

    N Long.

    E

    h Focus depth km Catalog C. Radu INFP, 2002

    1550 Oct. 26 45.4 24.6 IX 7.2 1829 July 1 47.5 22.2 35 6.2

    1879 Oct. 10 44.7 21.7 7 VIII 5.3 5.3 1901 Apr. 02 45.5 20.75 18 VII 5.0 5 1916 Jan. 26 45.4 24.6 21 VIII 6.4 1959 May 29 45.65 21.2 5 VII-VIII 5.0 5 1991 Jul. 12 45.38 21.05 11 VIII 5.7 5.6 1991 Jul. 18 44.90 22.35 12 VIII 5.6 5.6 1991 Dec. 02 45.45 21.12 9 VIII 5.6 5.5

    The magnitude in Constantinescu & Marza catalogue was the surface magnitude, MS,

    later tacitly assimilated as MGR (Marza, 1995). Example of Romanian earthquakes Catalogue for the most severe i.e. subcrustal Vrancea source in Romania and the most energetic century i.e. XX-century is given in Table 3. Table 3. Catalogue of subcrustal Vrancea earthquakes (Mw 6.3 ) occurred during the 20th century

    RADU Catalogue, 1994

    MARZA Catalogue,

    1980

    www.infp.roCatalogue,

    1998

    Date Time (GMT) h:m:s

    Lat. N

    Long. E

    h, km I0 MGR Mw I0 Ms Mw1903 13 Sept 08:02:7 45.7 26.6 >60 7 6.3 - 6.5 5.7 6.3 1904 6 Feb 02:49:00 45.7 26.6 75 6 5.7 - 6 6.3 6.6 1908 6 Oct 21:39:8 45.7 26.5 150 8 6.8 - 8 6.8 7.1 1912 25 May 18:01:7 45.7 27.2 80 7 6.0 - 7 6.4 6.7 1934 29 March 20:06:51 45.8 26.5 90 7 6.3 - 8 6.3 6.6 1939 5 Sept 06:02:00 45.9 26.7 120 6 5.3 - 6 6.1 6.2 1940 22 Oct 06:37:00 45.8 26.4 122 7 / 8 6.5 - 7 6.2 6.5 1940 10 Nov 01:39:07 45.8 26.7 1501) 9 7.4 - 9 7.4 7.7 1945 7 Sept 15:48:26 45.9 26.5 75 7 / 8 6.5 - 7.5 6.5 6.8 1945 9 Dec 06:08:45 45.7 26.8 80 7 6.0 - 7 6.2 6.5 1948 29 May 04:48:55 45.8 26.5 130 6 / 7 5.8 - 6.5 6.0 6.3 1977 4 March 2) 19:22:15 45.34 26.30 109 8 / 9 7.2 7.5 9 7.2 7.4 1986 30 Aug 21:28:37 45.53 26.47 133 8 7.0 7.2 - - 7.1 1990 30 May 10:40:06 45.82 26.90 91 8 6.7 7.0 - - 6.9 1990 31 May 00:17:49 45.83 26.89 79 7 6.1 6.4 - - 6.4 1) Demetrescus original (1941) estimation: 150Km; Radus initial estimation (1974) was 133 km 2) Main shock

    The envelope of the peak ground acceleration (PGA, cm/s2) recorded in Romania during the last 3 strongest Vrancea earthquakes is interpolated in Figure 5. This clearly shows the directivity pattern (N45OE) of the subcrustal Vrancea sources activity.

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    SIXTH FRAMEWORK PROGRAMME PRIORITY FP6-2002-INCO-MPC-1

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    100 0 100 200 Kilometers

    ArcView GIS version 3.1, ESRI Inc. CA.

    # Epicenters of strong Vrancea events (Mw > 6.9)

    Lungu, Aldea, 1999

    N

    EW

    S

    March 4, 1977

    Mw=7.5h=109 km

    Aug.30, 1986

    May 30, 1990

    Mw=7.2h=133 km

    Mw=7.0h=91 km

    Mw - moment magnitudeh - focus depth

    200 - 300150 - 20075 - 1500 - 75

    PGA, cm/s2

    ROMANIA. Maximum peak ground acceleration PGA, cm/s2 recorded during 1977, 1986 and 1990 VRANCEA earthquakes

    Seismic stations with free-field records:

    & Bulgaria network

    $ GEOTEC network&

    # INCERC network% INFP network

    R. of Moldova network

    Figure 5. Maximum recorded peak ground acceleration during the last Vrancea strong events Based on the results of probabilistic seismic hazard assessment for Vrancea source (Lungu et al., 1995...2002) and taking into account the contributions from the crustal seismic sources around Romania, Figure 6 presents the proposed hazard map for the new code for design of earthquake resistant buildings in Romania, P100-2004. The map give the design peak ground acceleration, ag for the MRI=100 yr seismic event. In the