Journal of Seismology

, Volume 22, Issue 6, pp 1529–1547 | Cite as

Regional minimum 1-D P-wave velocity model for a new seismicity catalogue with precise and consistent earthquake locations in southern Iran

  • H. Kianimehr
  • E. Kissling
  • F. YaminifardEmail author
  • M. Tatar


For faster and more robust ray tracing in 1-D velocity models and also due to the lack of reliable 3-D models, most seismological centers use 1-D models for routine earthquake locations. In this study, as solution to the coupled hypocenter-velocity problem, we compute a regional P-wave velocity model for southern Iran that can be used for routine earthquake location and also a reference initial model for 3-D seismic tomography. The inversion process was based on travel time data from local earthquakes paired reports obtained by merging the catalogues of Iranian Seismic Center (IRSC, 6422 events) and by the Broadband Iranian National Seismic Network (BIN, 4333 events) for southern Iran in the period 2006 through July 2017. After cleaning the data set from large individual reading errors and by identifying event reports from both networks belonging to same earthquake (a process called event pairing), we obtained a data set of 1115 well-locatable events with a total number of 24,606 P-wave observations. This data set was used to calculate a regional minimum 1-D model for southern Iran as result of an extensive model search by trial-and-error process including several dozens of inversions. Significantly different from previous models, we find a smoothly increasing P-velocity by depth with velocities of 5.8 km/s at shallow and velocities of 6.4 km/s at deepest crustal levels. For well-locatable events, location uncertainties are estimated in the order of ± 3 km for epicenter and double this uncertainty for hypocentral depth. The use of the minimum 1-D model with appropriate station delays in routine hypocenter location processing will yield a high-quality seismic catalogue with consistent uncertainty estimates across the region and it will also allow detection of outlier observations. Based on the two catalogues by IRSC and BIN and using the minimum 1-D model and station delays for all stations in the region, we established a new combined earthquake catalogue for southern Iran. While the general distribution of the seismicity corresponds well with that of the two individual catalogues by IRSC and BIN, the new catalogue significantly enhances the correlation of seismicity with the regional fault systems within and between the major crustal blocks that as an assembly build this continental region. Furthermore, the unified seismic catalogue and the minimum 1-D model resulting from this study provide important ingredients for seismic hazard studies.


Earthquake location Merging travel time Regional minimum 1-D P-wave velocity model Earthquake catalogue Southern Iran 



The data used in our study were kindly provided by IRSC and BIN seismological centers, and also we used phase information of some stations from Earthquake Monitoring Program of Oman (network code OM) which is handled by Sultan Qaboos University, and of stations from UAE networks got from their website: We are grateful to the staff of both IRSC and BIN who routinely picked and also let us know general information about stations. Maps and figures were plotted using the Generic Mapping Tools (Wessel and Smith 1998).


  1. Aghanabati A (2004) Geology of Iran. Geological Survey of Iran, Tehran 586 pp. (in Persian)Google Scholar
  2. Ambraseys NN, Melville C (1982) A history of Persian earthquakes. Cambridge Univ. Press, Cambridge, p 240Google Scholar
  3. Askari R, Ghods A, Sobouti F (2009) Calibration of an ML scale in the Alborz region, northern Iran. Bull Seismol Soc Am 99:268–276CrossRefGoogle Scholar
  4. Berberian M, King GCP (1981) Towards a paleogeography and tectonic evolution of Iran. Can J Earth Sci 18:210–265CrossRefGoogle Scholar
  5. Berberian M, Yeats RS (1999) Patterns of historical earthquake rupture in the Iranian Plateau. Bull Seismol Soc Am 89:120–139Google Scholar
  6. Berberian M, Jackson J, Fielding E, Parsons BE, Priestley K, Qorashi M, Talebian M, Walker RT, Wright TJ, Baker C (2001) The 1998 March 14 Fandoqa earthquake (Mw 6.6) in Kerman province, southeast Iran: re-rupture of the 1981 Sirch earthquake fault, triggering of slip on adjacent thrusts and the active tectonics of the Gowk fault zone. Geophys J Int 146:371–398CrossRefGoogle Scholar
  7. Chatelain JL, Roecker SW, Hatzfeld D, Molnar P (1980) Microearthquake seismicity and fault plane solutions in the Hindu Kush region and their tectonic implications. J Geophys Res 85:1365–1387CrossRefGoogle Scholar
  8. DAN Users Guide, Release 2.53 (1995) Nanometrics Inc., KanataGoogle Scholar
  9. Hesami Kh, Jamali F, Tabasi, H (2003) Major active faults of Iran. 1:2,500,000, International Institute of Earthquake Engineering and Seismology (IIEES), TehranGoogle Scholar
  10. Husen S, Kissling E, Flueh E, Asch G (1999) Accurate hypocentre determination in the seismogenic zone of the subducting Nazca plate in northern Chile using a combined on-/offshore network. Geophys J Int 138:687–701CrossRefGoogle Scholar
  11. Husen S, Quintero R, Kissling E, Hacker B (2003) Subduction-zone structure and magmatic processes beneath Costa Rica constrained by local earthquake tomography and petrological modeling. Geophys J Int 155:11–32CrossRefGoogle Scholar
  12. Husen S, Kissling E, Clinton JF (2011) Local and regional minimum 1D models for earthquake location and data quality assessment in complex tectonic regions: application to Switzerland. Swiss J Geosci 104(3):455–469CrossRefGoogle Scholar
  13. Hutton LK, Boore DM (1987) The ML scale in Southern California. Bull Seismol Soc Am 77(6):2074–2094Google Scholar
  14. Kanamori H (1983) Magnitude scale and quantification of earthquakes. Tectonophysics 93:185–199CrossRefGoogle Scholar
  15. Kissling E (1988) Geotomography with local earthquakes. Rev Geophys 26:659–698CrossRefGoogle Scholar
  16. Kissling E, Ellsworth WL, Eberhart-Phillips D, Kradolfer U (1994) Initial reference models in local earthquake tomography. J Geophys Res 99:19635–19646CrossRefGoogle Scholar
  17. Kissling E, Kradolfer U, Maurer H (1995) VELEST users guide: short introduction. Institute of Geophysics and Swiss Seismological Service, ETH, ZurichGoogle Scholar
  18. Lee W H K, Lahr J C (1975) HYPO71: a computer program for determining hypocenter, magnitude, and first motion pattern of local earthquakes. U. S. Geol Surv Open File Rep 75–311Google Scholar
  19. Lienert BRE, Havskov J (1995) A computer program for locating earthquakes both locally and globally. Seismol Res Lett 66:26–36CrossRefGoogle Scholar
  20. Masson F, Anvari M, Djamour Y, Walpersdorf A, Tavakoli F, Daignières M, Nankali H, Gorp SV (2007) Large-scale velocity field and strain tensor in Iran inferred from GPS measurements: new insight for the present-day deformation pattern within NE Iran. Geophys J Int 170:436–440CrossRefGoogle Scholar
  21. Mattei M, Cifelli F, Muttoni G, Zanchi A, Berra F, Mossavvari F, Eshraghi SA (2012) Neogene block rotation in central Iran: evidence from paleomagnetic data. Geol Soc Am Bull 124(5–6):943–956CrossRefGoogle Scholar
  22. Moinfar A A, Naderzadeh A, Nabavi M H (2012) New Iranian seismic hazard zoing map for new edition of seismic code and its comparison with neighbor countries. 15 WCEE, LISBOAGoogle Scholar
  23. Nuttli OW (1973) Siesmic wave attenuation and magnitude relations for eastern North America. J Geophys Res 78:876–885CrossRefGoogle Scholar
  24. Quintero R, Kissling E (2001) An improved P-wave velocity reference model for Costa Rica. Geofis Int 40:3–19Google Scholar
  25. Rezapour M (2005) Magnitude scale in the Tabriz seismic network. J Earth Space Phys 31(1):13–21Google Scholar
  26. Searcy C K (2003) Station corrections for the Katmai region seismic network. USGS Open-File Report USAGoogle Scholar
  27. Sengör A (1990) A new model for the late Paleozoic-Mesozoic tectonic evolution of Iran and implications for Oman, in The Geology and Tectonics of the Oman Region, edited by Robertson A, Searle M, and Ries A. Geol Soc Spec Publ 49:797–831Google Scholar
  28. Shad Manaman N, Shomali H (2010) Upper mantle S-velocity structure and Moho depth variations across Zagros belt, Arabian-Eurasian plate boundary. Phys Earth Planet Inter 180:92–103CrossRefGoogle Scholar
  29. Solarino S, Kissling E, Sellami S, Smriglio G, Thouvenot F, Granet M, Bonjer K, Slejko D (1997) Compilation of a recent seismicity data base of the greater alpine region from several seismological networks and preliminary 3-D tomographic results. Ann Geofis 40:161–174Google Scholar
  30. Thurber CH (1992) Hypocenter-velocity structure coupling in local earthquake tomography. Phys Earth Planet Inter 75:55–62CrossRefGoogle Scholar
  31. Vernant P, Nilforoushan F, Hatzfeld D, Abbassi MR, Vigny C, Masson F, Nankali H, Martinod J, Ashtiani A, Bayer R, Tavakoli F, Chéry J (2004) Present-day crustal deformation and plate kinematics in the Middle East constrained by GPS measurements in Iran and northern Oman. Geophys J Int 157:381–398CrossRefGoogle Scholar
  32. Walker R, Jackson J (2004) Active tectonics and late Cenozoic strain distribution in central and eastern Iran. Tectonics 23:TC5010. CrossRefGoogle Scholar
  33. Walpersdorf A, Manighetti I, Mousavi Z, Tavakoli F, Vergnolle M, Jadidi A, Hatzfeld D, Aghamohammadi A, Bigot A, Djamour Y, Nankali H, Sedighi M (2014) Present-day kinematics and fault slip rates in eastern Iran, derived from 11 years of GPS data. J Geophys Res Solid Earth 119:1359–1383. CrossRefGoogle Scholar
  34. Wessel P, Smith WHF (1998) New improved version of generic mapping tools released. Eos Trans Am geophys Un 79(47):579CrossRefGoogle Scholar
  35. Yaminifard F, Hatzfeld D, Farahbod AM, Paul A, Mokhtari M (2007) The diffuse transition between the Zagros continental collision and the Makran oceanic subduction (Iran): microearthquake seismicity and crustal structure. Geophys J Int 170:182–194CrossRefGoogle Scholar

Copyright information

© Springer Nature B.V. 2018

Authors and Affiliations

  1. 1.International Institute of Earthquake Engineering and Seismology (IIEES)TehranIran
  2. 2.Institute of Geophysics, Swiss Federal Institute of Technology, ETH, ZurichZurichSwitzerland

Personalised recommendations