Seismicity and Strong Motion Stations in Euro-Mediterranean Region

Transcription

1 STRONG-MOTION DATA ACQUISITION, PROCESSING AND UTILIZATION IN TURKEY M.Erdik, Y.Fahjan and E.Durukal Bogazici University, Istanbul, Turkey

2 Seismicity and Strong Motion Stations in Euro-Mediterranean Region

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4 There exist some 361 strong motion accelerographs in Turkey. About 158 accelerographs (4% analog, 6% digital) are owned and operated by Earthquake Research Department (ERD) of Ministry of Public Works as the national strong motion network distributed all around Turkey. About 2 digital strong motion accelerographs are owned and operated by Kandilli Observatory and Earthquake Research Institute (KOERI) of Bogazici University as dense urban network in and around Istanbul (Rapid response and early warning system, structural instrumentations) and North Cyprus. The total number of records obtained by the network is about 5. The most important earthquakes in this catalog are the 1992 Erzincan, 1995 Dinar, 1998 Adana-Ceyhan, 1999 Kocaeli and Duzce earthquakes.

5 National Network - Ministry of Public Works (ERD) Digitized analog and digital acceleration data in ASCII format, without any processing are provided on the Internet since 1998 by the General Directorate of Disaster Affairs

6 KOERI GROUND MOTION NETWORKS

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10 The routine strong ground motion progressing procedure that has been used on several papers originating from KOERI essentially use the following procedure. 1. Low - pass filter the uncorrected accelerogram (25 Hz-5Hz) 2. Least square fit a straight line to the acceleration trace 3. Integrate the acceleration to obtain velocity 4.. High - pass filter velocity using a recursive Butterworth filter with a cut - off frequency determined from the shape of the FAS. 5. Least square fit a straight line to the filtered velocity. 6. Differentiate velocity to obtain the corrected acceleration. 7. Integrate velocity to obtain the displacement. 8. Least square fit a straight line displacement. 9. Add the slope of the line of step 8 to the velocity of step 5 for the corrected velocity. This routine preserves the phase of the accelerogram and the correspondence of acceleration, velocity and displacement traces. However, the initial motion estimates for velocity and displacement may influence the shape of the response spectra.

11 Zare and Bard (22) have processed a selected a set of 21 records from the available strong motion data set in Turkey. After a simple base-line correction, the appropriate frequency band for each record is determined on the basis of the ratio of Fourier Amplitude Spectra of appropriately selected signal and noise windows. The dominant signal band the empirical Fourier amplitude spectrum is also compared with the theoretical shape of the far field Fourier amplitude spectrum of acceleration. After determination of the reliable frequency band, the signal window is band pass filtered with a 2nd order Butterworth filter. The fundamental frequency of vibration at the recording stations was determined on the basis of the H/V ratio of the records.

12 PGA (%g) in 1999 Kocaeli Earthquake

13 1, EW Accelerations 8 YPT 6 4 accelera ation (cm/s2) 2 SKR -2-4 ARC -6-8 IZM -1, time (s) To obtain the correct displacements I an and Chen (1995) method as sed hich To obtain the correct displacements Iwan and Chen (1995) method was used, which essentially involved segmented polynomial baseline fit to velocity.

14 2 EW Velocities 15 1 YPT 5 velocity (cm/s s) -5 SKR -1 ARC -15 IZM time (s)

15 35 EW Displacements 3 25 YPT 2 15 dis splacement (c cm) SKR -15 ARC IZM time (s)

16 After 1999 Kocaeli and Duzce earthquakes KOERI has compiled and disseminated all strong motion data (Ozbey and Fahjan, 2). Array microtremor and SASW methods were used to determine the velocity profile (NEHRP site classifications) at the KOERI stations. Non Non-earthquake signals caused by voltage fluctuation, quarry explosions, vehicle-generated waves, etc. were eliminated Record-event event (earthquake) matching were done. Since no processing has been applied, these records qualify as an uncorrected data set. Celebi et al (21) provided a collection of all available strong ground motion records from main shock and aftershocks of 1999 earthquakes. All the data are presented in ASCII format as provided by the contributing agency. There is no event association for the aftershocks.

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18 ISTANBUL EARTHQUAKE RAPID RESPONSE STATIONS

19 One hundred (1) of the strong motion recorders are stationed in dense settlements in the Metropolitan area of Istanbul in dial- up mode for Rapid Response information generation. System consists of the following components: (1) Monitoring system composed of various sensors, (2) Communication link, (3) Data processing facilities that converts information, and (4) System that issues and communicates response information and early warning. data the to rapid

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21 All of the instruments were calibrated in the laboratory using aair-bed electro-magnetic shaker. Additional bi-directional tilt tests at site were conducted during installation

22 After triggered by an earthquake, each station processes the streaming three-channel strong motion data to yield the spectral accelerations at specific periods, 12Hz filtered PGA and PGV and sends these parameters in the form of SMS messages at every 2s directly to the main data center through the GSM communication system by using several base stations, microwave system and landlines.

23 Data Transmission over SMS G2 G1 BTS BSC MSC2 MSC1 SMSC Active SMSC Standby Gx SMSC interface will be Mobile Originated Short Message to predefined numbers. SMSC will communicate with Application Server over SMPP protocol. Application Server-Kandilli Server Interface will be fully redundant socket communication over Leased Line and M/W. ARIA Backbone Kandilli Servers Application Server Alpha Application Server Beta FW Leased Line 64k M/W

24 MAIN DATA CENTER

25 Spectral displacements obtained from the SMS messages sent from stations are interpolated to determine the spectral displacement values at the center of each geo-cell (.1 x.1 ). The earthquake demand at the center of each geo-cell is computed using these spectral displacements. Using the capacities of the buildings (24 types) in each geo-cell the building damage is computed tdb by using the spectral-displacement based fragility curves (HAZUS Procedure).

26 5.Hz 2.Hz 3.33Hz 1.11Hz

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28 Number of Collapsed Buildings per Cell (Simulated from random data and communicated to end users every day)

29 Municipality Governorate Municipality 1 st Army Communication of Rapid Response Message (Damage Maps) (Mobile phones and PDA s)

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34 PGA Distribution

35 5.Hz 3.33Hz 2.Hz 1.11Hz

36 Building Damage Distribution

37 DATA AVAILIBILITY National strong motion network data in raw (or uncorrected) format (ASCII) can be obtained from ( The strong motion data recorded by the Istanbul Earthquake Rapid Response Network can be obtained from edu tr/depremmuh/ewrr/ewrrmain htm Most of the database is also included in the CD volume of European Strong Motion Database ( The strong motion data compilation conducted by USGS ( also includes KOERI strong motion records. Selected events from KOERI database can be reached in PEER Strong Motion Database ( and COSMOS Virtual Data Center (

38 ATTENUATION STUDIES Gulkan and Kalkan (22) have developed attenuation relationships for peak ground acceleration (PGA) and 5 percent damped spectral acceleration (SA) from 47 strong ground motion records recorded in 19 earthquakes. Using a database consisting of 195 recordings from 17 recent events an attenuation model Özbey et al. (24) has developed for peak ground acceleration and 5%-damped spectral acceleration for periods up to 4 seconds. Both studies conclude that WUS (+worldwide) based attenuation relationships predictions are above the (up to 1SD) the predictions based on data from Turkey (actually dominated by 1999 events).

39 Comparison of PGA predictions from the proposed attenuation model with those from two W.U.S. models for for Soil Class B and Mw = 7.4.

40 Comparison of 1s SA predictions from the proposed attenuation model with those from two W.U.S. models for for Soil Class B and Mw = 7.4.

41 KOERI STRUCTURAL INSTRUMENTATION ARRAYS

42 AYASOFYA STRONG MOTION ARRAY

43 SÜLEYMANİYE STRONG MOTION ARRAY

44 Accelerations recorded by the AyaSofya array during the 12 November 1999 Düzce earthquake

45 Accelerations recorded by the Süleymaniye array during the 17 August 1999, Kocaeli earthquake

46 ) Top of NW Main Pier Crown of N Main Arch Top of NE Main Pier dis splacement (cm) Crown of W Main Arch Crown of E Main Arch m) displacement (c t (cm) displacement.1.5 W N.5 E -.5 S Top of SW Main Pier Crown of S Main Arch displacement (cm) displacement (cm) First mode of vibration Top of SE Main Pier of Hagia.1 Sophia. 5.5 Dominant sense of -.1 vibration EW displacement (cm)

47 ) Top of NW Main Pier Crown of N Main Arch Top of NE Main Pier dis splacement (cm) Crown of W Main Arch Crown of E Main Arch displacement (c cm) displacement (cm).1.5 W N.5 E -.5 S Top of SW Main Pier displacement (cm) Crown of S Main Arch displacement (cm) Second Top of SE Main Pier mode of.1 vibration 5.5 of Hagia Sophia. -.1 Dominant sense of displacement (cm) vibration NS -.5

48 ) Top of NW Main Pier Crown of N Main Arch Top of NE Main Pier isplacement (cm di Crown of W Main Arch Crown of E Main Arch displacement (c cm) Y X t (cm) displacement Top of SW Main Pier Crown of S Main Arch Top of SE Main Pier displacement (cm) displacement (cm) displacement (cm) First mode of vibration of Suleymaniye Dominant sense of vibration +/- X

49 BOĞAZİÇİ SUSPENSION BRIDGE STRONG MOTION ARRAY

50 FATİH SULTAN MEHMET SUSPENSION BRIDGE STRONG MOTION ARRAY

51 SAMPLE RECORD FSM BRIDGE Station FS1 (Av. Wind Speed 4kph, Gusting 7kph)

52 2 ) Acc (m/s 2 Time History of North Station recorded at 24/2/13, : LONG TRANS VERT Vel (m/s s) Disp (m m) Time (s) Time (s) Time (s)

53 İŞ-KULE ENRON-TRAKYA ELEKTRIK

54 INSTRUMENT DEVELOPMENT The prototype low-cost accelerograph (KANDLE-1) uses MEMS (Micro-Electro Mechanical Systems) accelerometers. KANDLE-1 is 18 bit 3 channel strong motion recorder system encompassing A/D converter, analog and digital filters, internal modem, RS232/RS485 communications, GPS timing, GSM communication, SDRAM memory and a removable USB memory card. The operational modes include: configuration, trigger/alarm mode (STA/LTA, PGA and CAV thresholds) and online data streaming. The full-scale range of the accelerometer is +/- 1.7g with a noise floor of about 1mg. RS485 Networking with optional wireless networking

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56 Thank you