Numerical modelling of seismic site effects incorporating non-linearity and groundwater level changes

Abstract

In the past decades, the necessity for detailed earthquake microzonation studies was recognized worldwide. Therefore, different approaches were established and applied. Unfortunately, the majority of these approaches are not based on pre-existing field data but require extensive seismic measurements and investigations. Furthermore, these approaches incorporate non-linearity inadequately and cannot take groundwater level changes into account. For this purpose, notably numerical models are most suitable. These models require a good knowledge of the local geological conditions (especially of the uppermost unconsolidated units), information about the geotechnical parameters of these units, and a hydrogeological model of the investigated area. Most of this information can be obtained from geotechnical investigations and surveys that have already been carried out in most densely populated areas. In a case study for Bucharest City, non-linear analyses were performed using software that is based on the visco-hypoplastic constitutive law. The results indicate that groundwater level changes have an important influence on duration and amplitude of ground response and thus should be considered for seismic microzonation studies. This approach can be used to display site effects and to identify different microzones taking different earthquake magnitudes and groundwater levels into account.

Keywords

microzonation / site effect / visco-hypoplasticity / non-linearity / Bucharest / Romania

References

Ansal A. M., Iyisan R., Güllü H.. Microtremor Measurements for the Microzonation of Dinar. Pure and Applied Geophysics, 2001, 158(12): 2525-2541.

Cid J., Susagna T., Goula X., . Seismic Zonation of Barcelona Based on Numerical Simulation of Site Effects. Pure and Applied Geophysics, 2001, 158(12): 2559-2577.

Cioflan C. O., Apostol B. F., Moldoveanu C. L., . Deterministic Approach for the Seismic Microzonation of Bucharest. Pure and Applied Geophysics, 2004, 161(5–6): 1149-1164.

Ciugudean V., Martinof G. H.. Geological, Geomorphological, and Hydrogeological Conditions in the City Area of Bucharest, 2000, Bucharest: S.C. Metroul S.A.

Ehret D., Kienzle A., Hannich D., . Seismic Microzonation of Bucharest Based on Non-linear Modelling. International Conference 250th Anniversary of the 1755 Lisbon Earthquake, 2005, Portugal: Lisbon 369 371

Fielitz W., Seghedi I.. Late Miocene-Quaternary Volcanism, Tectonics and Drainage System Evolution in the East Carpathians, Romania. Tectonophysics, 2005, 410(1–4): 111-136.

Ghenea C.. van Couvering J. A.. The Pliocene-Pleistocene Boundary in Romania. The Pleistocene Boundary and the Beginning of the Quaternary, 1997, London: Cambridge University Press 216 221

Giardini D., Jiménez M. J., Grünthal G.. European-Mediterranean Seismic Hazard Map, Scale 1: 5 000 000. European Seismological Commission Hannich, D., Hötzl, H., Cudmani, R., 2006a. The Influence of Groundwater on Damage Caused by Earthquakes—An Overview. Grundwasser, 2003, 11(4): 286-294.

Hannich, D., Hötzl, H., Ehret, D., et al., 2005. The Impact of Hydrogeology on Earthquake Ground Motion in Soft Soils. International Conference 250th Anniversary of the 1755 Lisbon Earthquake, Lisbon, Portugal. 358–361

Hannich D., Huber G., Ehret D., . SCPTU-Techniques Used for Shallow Geologic/Hydrogeologic Site Characterization in Bucharest, Romania. ESG 2006-Third International Symposium on the Effects of Surface Geology on Seismic Motion, Grenoble, France, 2006, 1: 981-992.

Herle I.. Gudehus G., Natau O.. Hypoplasticity and Granulometry of Simple Grain Assemblies. Veröffentlichungen des Institutes für Bodenmechanik und Felsmechanik der Universität Fridericiana in Karlsruhe, 1997, Karlsruhe: Institut für Bodenmechanik und Felsmechanik der Universität Karlsruhe 135

Herle I., Gudehus G.. Determination of Parameters of a Hypoplastic Constitutive Model from Properties of Grain Assemblies. Mechanics of Cohesive-Frictional Materials, 1999, 4(5): 461-486.

Kienzle A., Hannich D., Wirth W., . A GIS-Based Study of Earthquake Hazard as a Tool for the Microzonation of Bucharest. Engineering Geology, 2006, 87(1–2): 13-32.

Liteanu E.. Geology of Bucharest City Area, 1952, Bucharest: Com. Geol. St. Tehn. Econ, Series E.I.

Lizcano A., Rinaldi V., Fuentes W. M.. Visco-hypoplastic Model for Pampean Loess. Mecánica Computacional, 2007, XXVI: 2646-2655.

Lungu D., Aldea A., Moldoveanu T., . Wenzel F., Lungu D., Novak O., . Near-Surface Geology and Dynamic Properties of Soil Layers in Bucharest. Vrancea Earthquakes: Tectonics, Hazard and Risk Mitigation, 1999, Dordrecht, Netherlands: Kluwer Academic Publishers 137 148

Lungu D., Cornea T., Nedelcu C.. Wenzel F., Lungu D., Novak O.. Hazard Assessment and Site-Dependent Response for Vrancea Earthquakes. Vrancea Earthquakes: Tectonics, Hazard and Risk Mitigation, 1999, Dordrecht, Netherlands: Kluwer Academic Publishers 251 267

Mândrescu, N., Radulian, M., 1999. Seismic Microzoning of Bucharest (Romania): A Critical Review. In: Wenzel, F., Lungu, D., Novak, O., eds., Vrancea Earthquakes: Tectonics, Hazard and Risk Mitigation. Kluwer Academic Publishers, Dordrecht, Netherlands. 109–121

Mândrescu N., Radulian M., Mârmureanu G.. Site Conditions and Predominant Period of Seismic Motion in the Bucharest Urban Area. Rev. Roum. Géophysique, 2004, 48: 37-48.

Martin M., Wenzel F.. High-Resolution Teleseismic Body Wave Tomography beneath SE-Romania. II. Imaging of a Slab Detachment Scenario. Geophysical Journal International, 2006, 164(3): 579-595.

Mason P. R. D., Seghedi I., Szákacs A., . Magmatic Constraints on Geodynamic Models of Subduction in the East Carpathians, Romania. Tectonophysics, 1998, 297(1–4): 157-176.

Nakamura Y.. Microtremor Measurements in the San Francisco Bay Region. Soil Mechanics and Foundation Engineering, 1990, 38(11): 13-18.

Niemunis A.. Extended Hypoplastic Models for Soils. Schriftenreihe des Institutes für Grundbau und Bodenmechanik der Ruhr-Universität Bochum, 2003, 34 233

Oncescu M. C., Marza V. I., Rizescu M., . Wenzel F., Lungu D., Novak O., . The Romanian Earthquake Catalogue between 1984–1996. Vrancea Earthquakes: Tectonics, Hazard and Risk Mitigation, 1999, Dordrecht: Kluwer Academic Publishers 43 47

Osinov V. A.. Natau O., Fecker E., Pimentel E.. A Numerical Model for the Site Response Analysis and Liquefaction of Soil during Earthquakes. Geotechnical Measurements and Modelling, 2003, Lisse: Swets & Zeitlinger 475 481

Osinov V. A.. Cyclic Shearing and Liquefaction of Soil under Irregular Loading: An Incremental Model for the Dynamic Earthquake-Induced Deformation. Soil Dynamics and Earthquake Engineering, 2003, 23(7): 535-548.

Pillai A. R.. The Rumanian Earthquake of November 10, 1940. Current Science, 1941, X(1): 15-16.

Raileanu V., Diaconescu C., Radulescu F.. Characteristics of Romanian Lithosphere from Deep Seismic Reflection Profiling. Tectonophysics, 1994, 239(1–4): 165-185.

Reyes D. K., Grandas C., Lizcano A., . Ling H. I., Callisto L., Leshchinsky D., . Numerical Modeling of Wave Propagation in Bogotá Soft Soils. Soil Stress-Strain Behavior: Measurement, Modeling and Analysis, 2007, Berlin: Springer-Verlag 779 789

Schäfer R.. Influence of the Construction Process on Strain Behaviour of Diaphragm Walls in Soft Clayey Soil. Instituts für Grundbau und Bodenmechanik der Ruhr-Universität Bochum, Bochum, 2004, 36 201

Sokolov V., Bonjer K. P., Oncescu M., . Hard Rock Spectral Models for Intermediate-Depth Vrancea, Romania, Earthquakes. Bulletin of the Seismological Society of America, 2005, 95(5): 1749-1765.

Sokolov V., Bonjer K. P., Rizescu M.. Cheng Y. T., Panza G. F., Wu Z. L.. Assessment of Site Effect in Romania during Intermediate Depth Vrancea Earthquakes Using Different Techniques. IUGG Special Volume: Earthquake Hazard, Risk, and Strong Ground Motion, 2004, Beijing: Seismological Press 295 320

Sokolov V., Bonjer K. P., Wenzel F.. Accounting for Site Effect in Probabilistic Assessment of Seismic Hazard for Romania and Bucharest: A Case of Deep Seismicity in Vrancea Zone. Soil Dynamics and Earthquake Engineering, 2004, 24(12): 929-947.

Sperner B., Lorenz F., Bonjer K., . Slab Break-off-Abrupt Cut or Gradual Detachment? New Insights from the Vrancea Region (SE Carpathians, Romania). Terra Nova, 2001, 13(3): 172-179.

Sperner, B., CRC 461 Team, 2005. Monitoring of Slab Detachment in the Carpathians. In: Wenzel, F., ed., Perspectives in Modern Seismology. Lecture Note in Earth Science, 105: 187–202

van den Ham G., Rohn J., Meier T., . A Method for Modeling of a Creeping Slope with a Visco-hypoplastic Material Law. Mathematical Geology, 2006, 38(6): 711-719.

van den Ham G., Rohn J., Meier T., . Finite Element Simulation of a Slow Moving Natural Slope in the Upper-Austrian Alps Using a Visco-hypoplastic Constitutive Model. Geomorphology, 2009, 103(1): 136-142.

von Wolffersdorff P. A.. A Hypoplastic Relation for Granular Materials with a Predefined Limit State Surface. Mechanics of Cohesive-Frictional Materials, 1996, 1(3): 251-271.

Wenzel F., Lorenz F. P., Sperner B., . Wenzel F., Lungu D., Novak O., . Seismotectonics of the Romanian Vrancea Area. Vrancea Earthquakes: Tectonics, Hazard and Risk Mitigation, 1999, Dordrecht: Kluwer Academic Publishers 15 25

Wortel M. J. R., Spakman W.. Subduction and Slab Detachment in the Mediterranean-Carpathian Region. Science, 2000, 290(5498): 1910-1917.