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Individual Seismogenic Sources

General information
HRIS004
Hvar North
Kastelic V.(1)
Kastelic V.(1)
1) Istituto Nazionale di Geofisica e Vulcanologia; Sismologia e Tettonofisica; Via di Vigna Murata, 605, 00143 Roma, Italy
17-Apr-2010
06-Nov-2013
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Parametric information
ParameterQualityEvidence
43.20 / 16.88 LD Based on data from Herak et al. (1995).
12.0 ER Calculated using the relationships from Wells and Coppersmith (1994).
7.1 ER Calculated using the relationships from Wells and Coppersmith (1994).
5.2 LD Based on data from Herak et al. (2001).
9.8 LD Based on data from Herak et al. (2001).
280 LD Based on data from Herak et al. (1995).
40 LD Based on data from Herak et al. (1995).
43 LD Based on data from Herak et al. (1995).
0.37 ER Calculated from Mo using the relationship from Hanks and Kanamori (1979).
0.3…1.4 EJ Inferred from geodetic data.
264…1233 AR Inferred from slip rate and average displacement.
5.9 LD Based on data from Herak et al. (1995).
LD=Literature Data; OD=Original Data; ER=Empirical Relationship; AR=Analytical Relationship;EJ=Expert Judgement;
 
Information about the associated Earthquakes
07 Jan 1962 Based on data from Herak et al. (1995).
Unknown See "Commentary" for information.
 
 
Active Faults
Active Folds
Commentary

 

 COMMENTS

This Individual Source belongs to a reverse fault running offshore of the southern coast of Hvar islands in a E-W to ENE-WSW direction. The source represents the MW = 5.9 seismic event of 7 January 1962, that is considered as a foreshock to the MW = 6.1 earthquake of 11 January.

A significant difference in the structural style of the area of Makarska-Hvar-Brac, with respect to eastern Adriatic coastal parts more to the NW and also to the SE, is the strike of prevailing structures. In this area the prevailing orientation of faults and fold axis is E-W oriented strike (Marincic, 1997) as the difference to other areas in which NW-SE oriented strike dominates. In accordance to the regional style the individual Makarska source displays an E-W to ENE-WSW oriented strike and a moderate NNE oriented dip. The total earthquake sequence consisted of two stronger shocks; besides the strongest MW = 6.1, the area was struck also by a MW = 5.9 shock four days prior to the main shock (Herak et al., 1996). The aftershocks were distributed in a general E-W orientation in 35 km long and 18 km wide cluster zone and distributed in depths between 5 and 20 km (Herak et al., 2001), which is in accordance with the regional depth distribution for this area obtained by Kuk et al. (2000). Focal mechanism solutions (Herak et al., 1995) reveal almost pure sinistral strike-slip movement on an ENE-WSW oriented fault plane with a small reverse component. Such kinematics was retrieved also for the recent main event of the 2003 Jabuka seismic sequence. Kinematics displaying sinistral strike-slip to oblique reverse movements are computed also for other instrumentally recorded earthquakes in the offshore Makarska area towards the Jabuka zone (Vannucci et al., 2004). Such kinematic behaviour is in accordance with N-S to NNE-SSW oriented compressive stress axis in the area and orientations of velocity vectors obtained by GPS measurements (Prelogovic et al., 2003).

The shock of 7 January lies at the NW margin of the 1962 seismic cluster. The earthquake occurred on a E-W striking, medium dipping fault plane and it demonstrated oblique sinistral/reverse kinematics. The activated volume of the crust in depth reached values from 5 to 10 kilometers.

The source's slip rate value has been updated according to the findings of geodynamic model (Kastelic and Carafa, 2012) and in the accordance with the hosting composite seismogenic fault's slip rate.

 
Pictures

 

Regional seismotectonic cross-section Details
Geographical and spatial position of the 1962 Hvar-Makarska earthquake series Details
Cross-section through the 1962 Hvar-Makarska earthquake series Details
References

 

Bennett, R.A, S. Hreinsdóttir, G. Buble, T. Bašic, Ž. Bacic, M. Marjanovic, G. Casale, A. Gendaszek and D. Cowan 2008 Eocene to present subduction of southern Adria mantle lithosphere beneath the Dinarides. Geology, 36, 1, 3-6.
Herak, M., D. Herak and S. Markušic 1996 Revision of the earthquake catalogue and seismicity of Craotia, 1908-1992. Terra Nova, 8, 86-94.
Herak, M., D. Herak and S. Markusic 1995 Fault plane solutions for earthquakes (1956-1995) in Croatia and neighbouring regions. Geofizica, 12, 43-56.
Herak, M., M. Orlic and M. Kunovec-Varga 2001 Did the Makarska earthquake of 1962 generate a tsunami in the central Adriatic archipelago? J. Geodyn., 31, 71-86.
Kuk, V., E. Prelogovic and I. Dragicevic 2000 Seismotectonically active zones in the Dinarides. Geologia Croatica, 53, 2, 295-303.
Marincic, S. 1997 Tectonic structure of the Island of Hvar (Southern Croatia). Geologica Croatica, 50, 1, 55-77.
Markušic, S., D. Herak, I. Ivancic and I. Sovic 1998 Seismicity of Croatia in the period 1993–1996 and the Ston-Slano earthquake of 1996. Geofizika, 15, 83-101.
Prelogovic, E., B. Pribicevic, Z. Ivkovic, I. Dragicevic, R. Buljan and B. Tomljenovic 2003 Recent structural fabric of the Dinarides and tectonically active zones important for petroleum-geological exploration in Croatia. Nafta, 55, 155-161.
Vannucci, G., S. Pondrelli, A. Argnani, A. Morelli, P. Gasperini and E. Boschi (eds) 2004 An atlas of Mediterranean seismicity. Ann. Geophys.-Italy, 47, 1, 334 pp., with CD-ROM.
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