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Address

University of Southern California
Department of Civil Engineering
Strong Motion Data Processing Laboratory
Kaprielian Hall 217
Los Angeles, Ca 90089-2531
Tel (213) 740-0570, fax (213) 744-1426

This laboratory was established in 1976 by Prof. Trifunac in support of the following research activities:

• Software development for routine and specialized processing of analogue and digital strong motion accelerograms.
• Routine processing of large accelerogram data sets and database organization for use in regression analyses.
• Large scale regression analyses for empirical scaling of strong ground motion.

• Advanced calibration of strong motion instruments.
• Ambient vibration surveys of full-scale structures.
• Structural health monitoring and damage detection

Faculty: M.D. Trifunac, V.W. Lee and M.I. Todorovska

The USC team is the leader in the field of earthquake data processing.  Prof. Trifunac is the author of the first modern software for earthquake accelerogram data processing, which he further developed since 1970's jointly with Prof. Lee.  The latest  LeAuto software package by Lee and Trifunac for automatic digitization of analogue accelerograms (using a flat-bed scanner and PC) is the most advanced of its kind.   The LeBatch software package for processing of digitized and digital strong motion accelerograms  is a standard in the profession.  Various versions of the data processing software developed by the USC group have been and continue to be used by government organizations, universities and industry in the US and in many countries in the world. The Trifunac-Lee team is also a leader in large scale regression analyses and detailed empirical modeling of amplitudes, spectra and duration of strong earthquake ground motion. Prof. Todorovska recently developed, jointly with former team member E.I. Novikova, and algorithm and software for routine processing of advanced field calibration records and related correction of accelerograms recorded on film for transducer misalignment and cross-axis sensitivity.  This capability is a unique feature of the USC software.  Another unique feature is the specialized software for instrument correction of coupled transducer-galvanometer recording systems and for force-balanced accelerometers developed by E.I. Novikova and M.D. Trifunac.  Former team member Ali Amini (currently a Professor of Electrical Engineering at Calif. State U. at Northridge) developed in 1986 a prototype of the first remote system for interrogation of strong motion acceleographs (SIFI) using a microprocessor and a modem.

As being simultaneously users and providers of large amounts of processed strong motion data, the USC team brings a unique perspective  to optimal solutions in strong motion data processing, balancing the demands for high quality processed data and efficient processing and database organization.

• Ambient vibration survey and earthquake response analyses of a 7-storey reinforced concrete building in Van Nuys, California, damaged by the 1994 Northridge earthquake (1994- ).
• Repeatability of Site Effects-: Northridge Aftershock Data Recorded at Strong Motion Stations  (1998; USGS).
• Gathering and Processing of 1994 Northridge Earthquake Records at Stations of the Los Angeles Strong Motion Network (1994-1995; USGS/NSF).
• New Generation Scaling Models for Amplitudes and Fourier and Response Spectra and Duration of Strong Ground Motion (1992-1995; Caltrans/City of Los Angeles/County of Los Angeles).
• Studies of strong ground motion and damage from the 1994 Northridge earthquake (1994- ).

• The LeAuto software package by Lee and Trifunac for automatic digitization of accelerograms recorded on film using flat-bed scanners and PC computers (Lee and Trifunac, 1990).
• The LeBatch software package for processing of digitized and digital strong motion accelerograms.  It consists of three programs (Volume 1, 2 and 3; Lee and Trifunac, 1990; Trifunac et al, 1998d) that perform baseline and instrument correction, filtering of high-frequency noise, integration in time of the recorded accelerations to obtain velocity and displacement, and further computation of Fourier and Response spectra (Lee and Trifunac, 1990).
• The Tilt software package for routine processing of field calibration records to determine the transducer angular sensitivity constants and misalignment angles (Todorovska et al., 1996; Todorovska, 1998; Todorovska et al., 1998).
• A software module for correction of accelerograms recorded on film for transducer misalignment and cross-axis sensitivity (Todorovska et al., 1996; Todorovska, 1998).
• A software module for instrument correction of coupled transducer-galvanometer recording systems and for force-balanced accelerometers (Novikova and Trifunac, 1991, 1992).
• System for Ambient Vibration Testing of structures and soils with PC based data acquisition and software for data analysis  (Gladkov et al., 1993).

1. Negmatullaev, S.Kh., M.I. Todorovska, & M.D. Trifunac (1999). Simulation of strong earthquake ground motion by explosions-experiments at the Lyaur testing range in Tajikistan, Soil Dynamics & Earthquake Engrg, 18(3), 189-207.
2. Trifunac, M.D., V.W. Lee and M.I. Todorovska (1999). Selected common problems in automatic digitization of accelerograms, Soil Dynamics & Earthquake Engrg,18, 519-530.
3. Todorovska, M.I. (1998). Cross-axis Sensitivity of Accelerographs with Pendulum like Transducers-Mathematical Model and the Inverse problem, Earthquake Engineering and Structural Dynamics, 27(10), 1031-1051.
4. Trifunac, M.D., M.I. Todorovska & V.W. Lee (1998). The Rinaldi strong motion accelerogram of the Northridge, California, earthquake of 17 January, 1994, Earthquake Spectra, 14(1), 225-239.
5. Todorovska, M.I., E.I. Novikova, M.D. Trifunac and S.S. Ivanovic (1995). Correction for Misalignment and Cross Axis Sensitivity of Strong  Earthquake Motion recorded by SMA-1 Accelerographs, Dept. of Civil Eng. Rep. No. 95-06, Univ. of Southern California, Los Angeles, California.
6. Todorovska, M.I., E.I. Novikova, M.D. Trifunac and S.S. Ivanovic (1998). Advanced Sensitivity Calibration of the Los Angeles Strong Motion Array, Earthquake Engineering and Structural Dynamics, 27(10), 1053-1068.
7. Lee, V.W. and M.D. Trifunac (1990). Automatic digitization and processing of accelerograms using PC, Report No. 90-03, Dept. of Civil Eng. U. of So. California, Los Angeles, CA.
8. Novikova, E.I. and M.D. Trifunac (1991). Instrument correction for the coupled transducer-galvanometer system, Dept. of Civil Eng. Report 91-02, Univ. of Southern California, Los Angeles, California.
9. Novikova, E.I. and M.D. Trifunac (1992). Digital instrument response correction for the Force Balance Accelerometer, Earthquake Spectra, 8(3), 429-442.

1. Todorovska, M.I, M.D. Trifunac, V.W. Lee, C.D. Stephens, K.A. Fogleman, C. Davis and R. Tognazzini (1999). The ML=6.4 Northridge, California, Earthquake  and Five M>5 Aftershocks between 17 January and 20 March 1994 - Summary of processed strong motion data,  Report No. 99-01, Dept. of Civil Engrg, U. of So. California, Los Angeles, CA.
2. V.W. Lee & M.D. Trifunac (1987). Strong Earthquake Ground Motion Data in EQUINFOS: Part I, Dept. of  Civil Engineering Report No  CE 87-01,  University of Southern California, Los Angeles, pp.  399.
3. L.R. Jordanovski, V.W. Lee, M.I. Manic, T. Olumceva, C. Sinadinovski, M.I. Todorovska & M.D. Trifunac (1987). Strong earthquake ground motion data in EQINFOS : Yugoslavia, Part I, Institute for Earthquake Engineering and Engineering Seismology, Univ. Kiril i Metodij, and Dept. of Civil Engrg, Univ. of Southern California, Rep. No. CE 87-05, Skopje, Yugoslavia, and Los Angeles, California, pp. 387.
4. Gupta, I.D., V. Rambabu & R.G. Joshi (1993).  Strong earthquake ground motion data in EQINFOS for India: Part IA, Edited by M.D. Trifunac, M.I. Todorovska & V.W. Lee, Central Water and Power Research Station, and Dept. of Civil Engrg, Univ. of Southern California, Rep. No. CE 93-03, Khadakwasla, Pune, India and Los Angeles, California, pp. 60.
5. Chandrasekaran, A.R., & J.D. Das (1993). Strong earthquake ground motion data in EQINFOS for India: Part IB, Edited by M.D. Trifunac, M.I. Todorovska and V.W. Lee, Univ. of Roorkee, Dept. of Earthqu. Engrg, and Univ. of Southern California, Dept. of Civil Engrg, Rep. No. CE 93-04, Khadakwasla, Pune, India and Los Angeles, California, pp. 90.
6. D. Nenov, G. Georgiev, I. Paskaleva, V.W. Lee & M.D. Trifunac (1990).  Strong Earthquake Ground Motion Data in EQINFOS: Accelerograms Recorded in Bulgaria Between 1981 And 1987,  Dept. of Civil Engineering Joint Report No  CE 90-02, Bulgarian Academy of Sciences, Central Lab. for Seismic Mechanics & Earthquake Engineering (C.L.S.M.E.E.), Bulgaria, and University of Southern California (U.S.C.), Los Angeles, U.S.A  55 pages.

1. V.W. Lee & M.D. Trifunac.  Empirical Equations Describing Attenuation of the Peaks of Strong Ground Motion, in terms of Magnitude, Distance, Path Effects and Site Conditions, Dept. of Civil Engineering Report No.  CE 95-02,  University of Southern California, Los Angeles  1995.
2. V.W. Lee & M.D. Trifunac.  Frequency Dependent Attenuation Function and Fourier Amplitude Spectra of Strong Earthquake Ground Motion in California,  Dept. of Civil Engineering Report No  CE 95-03, University of Southern California, Los Angeles, 1995.
3. V.W. Lee & M.D. Trifunac.   Pseudo Relative Velocity Spectra of Strong Earthquake Ground Motion in California, Dept. of Civil Engineering Report No  CE 95-04, University of Southern California, Los Angeles, 1995.
4.  V.W. Lee & M.D. Trifunac.  Characteristics of Earthquake Ground Motions for Seismic Design, Southern California Earthquake Center Report, Task H-1:  Final Task Report, Vol. I: Empirical Equations Describing Attenuation of Horizontal Peaks of Strong Ground Motion in Terms of Magnitude, Distance, Path Effects and Site Conditions, Dept. of DEpt. of Civil Eng. Report No. CE 95-02,  University of Southern California, Los Angeles,  409  pages  Dec, 1995.
5. V.W. Lee & M.D. Trifunac.  Characteristics of Earthquake Ground Motions for Seismic Design, Southern California Earthquake Center Report, Task H-1: Final Task Report, Vol. II: Frequency Dependent Attenuation Functions and Fourier Amplitude Spectra of Horizontal Strong Earthquake Ground Motion in California, Dept. of Civil Eng. Report No. CE 95-03, University of Southern California, Los Angeles 355  pages  Dec, 1995.
6. V.W. Lee & M.D. Trifunac.  Characteristics of Earthquake Ground Motions for Seismic Design, Southern California Earthquake Center Report, Task H-1: Final Task Report, Vol. III: Pseudo Relative Velocity Spectra of Horizontal Strong Earthquake Ground Motion in California, Dept. of Civil Eng. Report No. CE 95-04, University of Southern California, Los Angeles, 332  pages  Dec, 1995.
7. Novikova, E.I. and M.D. Trifunac (1994). Duration of Strong Ground Motion in Terms of Earthquake Magnitude Epicentral Distance, Site Conditions and Site Geometry,  Earthquake Eng. and Structural Dynamics, Vol. 23, No. 6, 1023--1043.
8. Novikova, E.I. and M.D. Trifunac (1994). Influence of Geometry of Sedimentary Basins on the Frequency Dependent Duration of Strong Ground Motion, Earthquake Eng. and Eng. Vibration, Vol. 14, No. 2, 7-44.
9. Novikova, E.I. and M.D. Trifunac (1993). Modified Mercalli Intensity Scaling of the Frequency Dependent Duration of Strong Ground Motion, Soil Dynamics and Earthquake Eng., Vol. 12, No. 5, 309-322.
10. Novikova, E.I. and M.D. Trifunac (1993). Modified Mercalli Intensity and the Geometry of the Sedimentary Basin as the Scaling Parameters of the Frequency Dependent Duration of Strong Ground Motion, with E.I. Novikova, Soil Dynamics and Earthquake Eng., Vol. 12, No. 4, 209-225.
11. Lee, V.W. and M.D. Trifunac (1993).  Empirical Scaling of Fourier Amplitude Spectra in Former Yugoslavia, European Earthquake Eng., Vol. VII, No. 2, 47-61.

1. Trifunac, M.D., S.S. Ivanovic and M.I. Todorovska (2000). Apparent periods of a building I: Fourier analysis, J. of Struct. Engrg, ASCE (submitted for publication).
2. Trifunac, M.D., S.S. Ivanovic and M.I. Todorovska (2000). Apparent periods of a building II:  time-frequency analysis, J. of Struct. Engrg, ASCE (submitted for publication).
3. Ivanovic, S.S., M.D. Trifunac, E.I. Novikova, A.A. Gladkov and M.I. Todorovska (1999). Instrumented 7-storey reinforced concrete building in Van Nuys, California: ambient vibration surveys following the damage from the 1994 Northridge earthquake, Dept. of Civil Eng. Rep. No. CE 99-03, pp. 92 (PDF).
4. Trifunac, M.D., S.S. Ivanovic, & M.I. Todorovska (1999). Experimental evidence for flexibility of a building foundation supported by concrete friction piles, Soil Dynamics & Earthquake Engrg, 18(3), 169-187.
5. Ivanovic, S.S. and M.D. Trifunac (1995). Ambient Vibration Survey of Full Scale Structures Using Personal Computers (with examples in Kaprielian Hall),  Dept. of Civil Eng. Rep. No. 95-05, Univ. of Southern California, Los Angeles, California.
6. Trifunac, M.D. and M.I. Todorovska (1999). Recording and interpreting earthquake response of full-scale structures, Proc. Nato Advanced Research Workshop on Strong-Motion Instrumentation for Civil Engineering Structures, June 2-5, 1999, Istanbul, Turkey, pp. 20 (PDF).
7. Ivanovic, S.S., M.D. Trifunac and M.I. Todorovska (1999). On identification of damage in structures via wave travel times, Proc. Nato Advanced Research Workshop on Strong-Motion Instrumentation for Civil Engineering Structures, June 2-5, 1999, Istanbul, Turkey, pp. 21 (PDF).