EAEE TASK GROUP TG2

INTERPRETATION OF STRONG-MOTION RECORDS FOR ENGINEERING APPLICATIONS

STRONG-MOTION DEVELOPMENT AND RESEARCH IN EUROPE

REPORT, AUGUST 1998

1. Introduction

Strong-motion instrumentation and recording in Europe and in the Middle East started much later than in United States and Japan, and developed slowly, chiefly with analogue instruments. Table 1 lists the year of the first recording made in various countries in the region since 1967. With the advent of digital recorders in recent years, this development increased rapidly, particularly because of the need to instrument major engineering works and public buildings and to comply with the requirements of hazard assessment and earthquake resistant design stipulated in EUROCODE-8.

2. Strong-motion networks

A recent survey made by the Working Group on Strong-motion Studies (TG2) of the European Association for Earthquake Engineering (EAEE) to assess the present state of strong-motion recording capabilities in the region, shows that although the total number of all the stations is difficult to estimate, the number of instruments operating in the free-field is close to 1,500 (Table 1). That we are aware of, the number of individual triaxial recordings made by earthquakes of all magnitudes during the last 28 years exceeds a conservative estimate of 2,500. Appendix 1 lists the agencies responsible for the operation of strong-motion networks and/or of data banks in Europe. This list does not include statistics from the former USSR and from a few other European countries, or from the European nuclear and oil industries.

The survey also shows that European strong-motion networks and individual stations have been established and are maintained with recurrent government subsidies or short term grants. They operate as independent state, industrial or university units with little or no coordination between them. Some of these networks are very well run but because of the closed system within which they operate, even within the same country, few cooperative research programmes have developed between them and only a fraction of their output reaches end-users, engineers and earth scientists alike.

3. Research programmes

Of the research programmes, the following are in progress: Arrays and dense networks to investigate path and soil amplification effects at:

Table 1. List of strong motion instruments

Country

First recording

Instrument

Organ

Analog

Digital

Albania

1988.01.09

SMA1

 

13

-

Algeria

1980.10.18

SMA1#

CGS

15

115*

Austria

1996.01.09

K2,SSA2, SM2

ZAMG

-

15*

Azores

1973.11.18

SMA1

 

 

 

Bosnia

 

 

 

14

-

Bulgaria

1977.11.03

SMA1

CLSM

47

-

Croatia

 

 

 

21

-

Germany

1977.02.11

Digital

LED

 

6*

Greece

1972.09.17

SMAC-B

ITSAK

75

9

 

 

 

NOA

48

12

 

 

 

UA

-

18

 

 

 

PPC

12

13

Hungary

 

SM2

GR

 

5

Iceland

1986.08.26

SMA1

UI

5

24

Iran

1972.04.18

SMA1#

BHRC

308*

910*

 

 

 

IIEES

21

-

Israel

1979.04.23

 

IPRG

42*

 

Italy

1970.11.21

MO-2

ENEL

302

-

 

 

 

ENEA

5

12

 

 

 

TRI

-

14

 

 

 

SSN

-

11

Liechtenstein

1992.05.06

MR2002

SSS

-

3

Macedonia

1967.12.02

AR-240

IZIIS

30

-

 

 

 

OA

-

4

Marocco

 

SSA1

CNC

-

5*

Montenegro

 

 

 

17

-

Netherland

 

SM2

RNMI

 

10*

Norway

 

 

NORSAR

 

 

Pakistan

1971.03.08

SMAC-B

WAPDA

28

-

Portugal

1969.02.28

SMAC-B

IST

2

25

Romania

1977.03.04

SMA1

 

41*

-

Serbia

 

 

 

9

-

Slovenia

 

 

GSS

13

 

Spain

1984.06.24

SMA1, SSA1

IGN

-

40

Switzerland

1984.09.05

SM2, MR2002

SSS

-

58

Tunisia

 

 

 

23*

 

Turkey

1975.09.16

SMA1, SM2, GSR12

DAD

95*

35

UK

1984.07.19

 

 

 

 

USSR

1976.05.17

 

 

 

 

 

 

 

Total*

1186

1344

#: First recording by UNESCO missions

Note: To the best of our knowledge the number of instruments shown are in free-field conditions unless marked with an asterisk.

4. Strong-motion data centres

These are few and are:

The Deprem Araþtýrma Dairesi (Turkey) data bank is accessible through the INTERNET at ftp://ftp.deprem. gov.tr in the directory /pub/sma, Inan et al. (1996).

The ITSAK (Greece) programme, a similar base and bank of strong-motion data from their network was made available on a CD-ROM in August,1997,ITSAK (1997).

The SSN/ENEL database and databank of strong motion data from the Umbro-Marchigiana (Italy) earthquake sequence of September and October 1997 are available on a CD-ROM since March 1998, SSN/ENEL (1998).

The Tripartite Project between Imperial College (UK), ENEL (Italy), ENEA (Italy), and IPSN (France) aims at creating an up-to-date data base and data bank of European strong-motion records to be made available shortly through INTERNET.

Data from other strong-motion centres still are not publicly available. However a number of data centre provides information on the Internet about the strong motion records archived in their databank and/or data of their accelerograph networks:

Europe:

Friuli strong motion network

The Friuli strong motion network consists of 10 broadband stations with strong motion sensors and several accelerographs installed in the epicentral area of the 1976 Friuli earthquake. Data are available upon request, http://www.dst.univ.trieste.it/raf.html.

Swiss national strong motion network

This network was installed by several Swiss governmental offices in order to study the characteristics of strong ground motion at different sites and the dynamic behaviour of main types of dams in Switzerland. It consists of 61 free-field stations as well as 34 dam-related stations installed in five different arrays. Acceleration time histories are available upon request, Smit (1998), http://seismo. ethz.ch/strong_motion/strong_motion.html.

SMA strong motion networks in Turkey (Deprem Arastirma Dairesi)

This national network consists of more than 100 free-field station installed all over Turkey, http://angora.deprem.gov.tr.

ESMC strong motion data bank

World-Wide Strong Motion Database (SMDB) collected by the European Seismological Commission, ESMC, http://perun.wdcb.rssi.ru/SMDB.

Overseas:

National Geophysical Data Center (NGDC)

NGDC acquires, processes and analyses technical data on earthquake hazards and disseminates them, http://www.ngdc.noaa.gov:

http://www.ngdc.noaa.gov/seg/hazard/smcat. html

National strong motion program (NSMP)

The NSMP-network consists of more than 1,000 strong motion instruments installed all over the USA, http://agram.wr.usgs.gov.

U.S. Geological Survey, Menlo Park

Provides uncorrected strong motion data from the “National strong motion program“ (NSMP) for recent earthquakes (1990-1996). There are also available accelerograms of historical earthquakes (1933-1986) in North and Central America and Hawaii from a number of agencies: ftp://agram.wr.usgs.gov

California strong motion instrumentation program

This INTERNET sites provides newly processed strong motion data from very recent Californian earthquakes,

ftp://ftp.consrv.ca.gov/pub/dmg/csmip.

Northern California Earthquake Data Centre (NCEDC)

NCEDC allows access to strong motion data from the Berkeley digital seismic network (BDSN) and from the strong motion borehole stations of the Hayward fault network, http://quake.geo.berkeley.edu.

Southern California Earthquake Center

The strong motion database (SMDB) provides access to strong motion data, including both parametric and time-series data for Southern California, http://quake.crustal.ucsb.edu/scec/smdb.

University of Southern California (USC)

USC strong motion data are available as well as other archive sites. Access to Northridge strong motion data by ftp://usc.edu/pub/todorovs.

Lahmont-Doherty/NCEER strong motion database

Access on-line parametric and time series from the “Lahmont-Doherty/NCEER strong motion database“ by using “strongmo“, an interactive menu-driven computer program. Guide and program available through anonymous ftp://129.236.10.30 in the directory “nceer“, http://www.ldeo.columbia.edu.

CIT strong motion accelerogram transfer system (SMARTS)

Browses, finds, views and plots accelerograms (time series and spectra) from the CALTECH and other databases. Also computes and plots inter-story demand spectrum,

http://www.eerl.caltech.edu/smarts/smarts.html.

National Center for Earthquake Engineering (NCEER)

NCEER guide for obtaining strong motion records as well as a set of chosen records from several important events, particularly in eastern North America, http://nceer.eng. buffalo.edu/agrams/agrams.html.

National research institute for earth science and disaster prevention (Japan)

The Kyoshin Net (K-Net) system provides strong motion data from more than 1,000 accelerograph stations installed in 1995-1996 throughout Japan, http://www.k-net.bosai.go.jp.

Guerrero strong motion network database

Access to acceleration records from the Guerrero accelerograph network (more than 30 digital strong motion accelerographs in Guerrero and neighbouring states in Mexico),

http://www.seismo.unr.edu/ftp/zeng /GUERRERO/guerrero.html.

Mexican strong motion network database

Provides access to Mexican strong motion database and links to the individual websites of the participating institutions, http://www.mexacceldb.unam.mx.

5. TG2 work programme

This programme was initiated by the European Association for Earthquake Engineering and aims at three work areas:

6. Attenuation laws

A number of peak ground acceleration attenuation laws have been published for Europe by Chiaruttini and Siro (1981), Sabetta and Pugliese (1987), Petrovski and Marcellini (1988), Ambraseys and Bommer (1991), Theodulidis and Papazachos (1992), Tento, Franceschina and Marcellini (1992), and Ambraseys (1995). Spectral ordinate relations have been published by Petrovski and Marcellini (1988), Pugliese and Sabetta (1989), Mohammadioun (1991), Caillot and Bard (1993), Lee (1995), Ambraseys, Simpson and Bommer (1996), and Ambraseys and Simpson (1996). A discussion of some of these laws is given by Ambraseys and Bommer (1995).

7. Discussion

During the past decade Imperial College (IC) / ENEL (Rome) / ENEA (Rome) / IPSN (Paris), the Tripartite Project Group (TPG), attempted to retrieve, process and analyse strong-motion records, chiefly analogue, from the European and Middle Eastern regions and to identify future needs for strong-motion information. In what follows we describe briefly the method we followed to retrieve and process these data and the lessons learnt from this exercise.

For the engineer, analysis of existing strong-motion recordings is the most common method used to estimate future ground shaking in a seismic hazard analysis. This method must rely on good quality databases, uniformly processed records supported by reliable seismological and soil mechanics information and reliable associated data banks.

Most of the TPG records come from events before 1995, and are in the period already analysed by the International Seismological Centre (ISC) and Harvard. Many of the earthquakes are of moderate magnitude and are reported from a relatively large enough number of stations to ensure reasonable azimuthal coverage. The locations found by ISC are therefore not likely to be in serious formal error and can be used as initial values for refinement. The main uncertainty is in depth of focus, and adjusting this could introduce compensating changes in position, particularly if the reporting stations are concentrated in a limited range of azimuth. For well-recorded events this effect is likely to be small, unless there are strong lateral velocity inhomogeneities, again unlikely in this area. The problem of depth may not be all that important in California but for certain parts of Europe and for other areas that are of interest to us, such as Central America for instance, focal depth is an important consideration.

Teleseismic locations are known to have larger uncertainties compared with those from local networks and the latter, when derived from special studies have been adopted in our analysis. Like epicentres, focal depths are also based on teleseismic arrival times alone and lack precision. Here again, results from special studies have been incorporated into our analysis to improve the quality of the data. Some of our records were generated by lower crust or subcrustal earthquakes and these have been treated separately.

The use of a unified magnitude scale in attenuation studies is an important consideration. Our adoption of Ms rather than ML stems from the fact that the former is not only the best estimator of the size of a crustal earthquake, but also because seismicity in Europe is generally evaluated in terms of Ms, it is necessary to use the same magnitude scale in attenuation relations. Moreover, we have chosen Ms because in some parts of the study area there are no ML determinations. Also, importantly, because we have access to a large number of station bulletins we can calculate Ms uniformly for almost all events that have generated strong-motion records from a sufficiently large number of stations using the Prague formula, which was checked for Europe (Ambraseys and Free, 1997). Equally important in the assessment of reliable source distance, particularly in the near field, is the exact location of the recording sites. This requirement is obvious and it may sound superfluous to check the station coordinates supplied by local networks. However, the re-examination of a number of files showed location errors by certain agencies, due to systematic reading errors or misprints up to 12 km. The solution to this problem has been the relocation of stations using hand-held GPS instruments.

The distance or source-path one assigns to a strong-motion record has a significant influence on the close-in behaviour of attenuation curves, particularly for small events for which location errors can be many times the source dimension. These errors accrue owing to errors in source and station locations. For most of the larger earthquakes we adopted the closest distance to the projection of the fault rupture. For small magnitude crustal events the source distance are close to the epicentral distance. However, the locations of some of the smaller events are poorly known and for this reason their location were re-evaluated or distances based on S-start times (first S-wave arrival-trigger time) were adopted.

Local site conditions (soil, topography, instrument location, housing and characteristics) at many European strong-motion stations are poorly known, particularly for the case of old sites which have been moved or abandoned, or for temporary stations. In terms of the soil conditions, the majority of sites can only be described at best in very general terms such as “soil” or “rock”. There are however, some stations for which there is no knowledge of the soil conditions. For a small percentage of European stations, relatively detailed descriptions of the local soil conditions do exist. These typically take the form of shear- and compressional-wave velocity profiles, although some are described in terms of Standard Penetration Test (SPT), void ratios, density, moisture content and other material property data. For these sites, velocity values can be estimated roughly via empirical relations.

The topographical details at most stations are even less well described. Where they do exist they may be given only in terms of very broad descriptions such as “at the top of a hill” without any reference to the hill dimensions or the surrounding geomorphology.

Instrument data is usually more readily available, at least in general terms of the instrument type and the structure in which it is housed. However, it is not uncommon to have no knowledge of the specific characteristics of the instrument (sensitivity and damping). Furthermore it is even less common to have detailed information regarding the structure in which the instrument is housed, for example building plans, and the specific location of the instrument within the structure beyond, for example, “the basement of a 3-storey structure”.

The TPG data bank and database contains information for Europe and worldwide regions. Specifically for Europe, the database contains information for 869 separate events, which are believed to be associated with strong-motion recordings. The completeness of data for these 869 events is variable ranging from only the basic event time to a complete set of magnitude values, moment, stress drop, fault type etc. The chronological distribution of these 869 events is shown in Table 2.

 

Table 2: Distribution by country and year of earthquakes, which are believed to be associated with strong-motion recordings.

Year

Total

Afg

Alb

Alg

Bul

Ger

Gre

Ice

Iran

Isr

Italy

Nor

Pak

Por

Rom

Spain

Tur

UK

USSR

Yug

1966

2

2

1967

3

3

1968

1

1

1969

1

1

1970

6

3

3

1971

4

1

2

1

1972

52

4

3

5

33

5

2

1973

14

1

2

2

1

2

1

5

1974

16

2

1

5

3

5

1975

31

3

22

2

2

2

1976

73

2

1

19

43

6

2

1977

24

1

1

1

1

1

4

8

2

1

3

1

1978

68

1

1

7

17

24

8

2

5

3

1979

127

1

6

1

21

5

93

1980

96

1

26

1

6

1

17

1

1

42

1981

37

1

8

6

6

1

3

12

1982

9

1

1

1

1

5

1983

29

2

2

1

18

1

2

3

1984

58

5

1

14

1

12

4

1

2

1

17

1985

26

1

1

17

4

3

1986

37

10

14

2

3

1

2

3

1

1

1987

21

5

12

2

1

1

1988

41

1

32

1

1

1

5

1989

10

2

3

1

1

3

1990

15

6

1

2

6

1991

12

2

10

1992

25

2

23

1993

20

20

1994

4

4

Unkn.

7

1

6

Afg: Afghanistan, Alb: Albania, Alg: Algeria, Bul: Bulgaria, Ger: Germany, Gre: Greece, Ice: Iceland, Isr: Israel, Nor: Norway, Pak: Pakistan, Por: Portugal, Rom: Romania, Tur: Turkey, UK: United Kingdom, USSR: Former Soviet Republic, Yug: Former Yugoslavia

 

Of the 869 events, 617 are known to have triggered strong-motion instruments. Information for 1249 triggered record sets from these 617 earthquakes is contained in the database. As previously, the completeness of information is variable ranging from basic identification of the triggered station through to peak acceleration values, intensity levels, source-site distances, instrument type, basic soil condition, ground or structural record etc. The distribution of these events and triggered stations is given in Table 3. From the 1249 known triggered record sets, 711 record sets from 331 separate earthquakes, giving a total of 2293 component records are held on the Imperial College data bank. The 711 triggered sets comprise 682 three component recordings, 20 two component recordings, and 9 single component records. The 2293 records include 195 duplicates resulting from multiple digitisation of records by the same or different agencies. The distribution of the 331 events and 711 record sets are shown in Table 4. Uniform surface-wave magnitude determination and distance calculations have been done where possible for these 331 events and 711 record sets.

The 2293 records in the data bank come from 261 individual strong-motion stations. Of these 261 sites, there are 19 for which there is no knowledge of the local soil conditions. For the other 242 stations, 182 can only be described in general terms following the classification scheme of Boore et al. (1993) which considers sites in one of four categories based on an average travel-time velocity to 30m depth, Vt30. For the remaining 60 stations, shear-wave velocity profiles are available, or can be estimated from SPT N-count and void ratio data. Of the 60 sites, local soil data is available at or very close to the instrument for 47 stations. For the remaining 13 sites, local soil data has been extrapolated from nearby stations or from general profiles which are considered representative for the area of concern.

Of the 261 stations associated with strong-motion records, 11 are considered to be structural. These 11 stations recorded 50 separate record sets giving 148 individual components. Most interest though at IC and from the TPG has been only with ground level records. Structural records have therefore been excluded from analyses. The resulting available ground-level data set is therefore comprised of 2145 component records (661 record sets) generated by 321 separate earthquakes and recorded by 250 different ground-level stations.

Table 3: Distribution by country and year of earthquakes, which are known to have triggered strong-motion instruments (Ev) and the associated number of triggered stations (St).

Year

Total

Alb

Alg

Bul

Ger

Gre

Ice

Iran

Isr

Italy

Nor

Pak

Por

Rom

Spain

Tur

UK

USSR

Yug

Ev

St

Ev

St

Ev

St

Ev

St

Ev

St

Ev

St

Ev

St

Ev

St

Ev

St

Ev

St

Ev

St

Ev

St

Ev

St

Ev

St

Ev

St

Ev

St

Ev

St

Ev

St

Ev

St

1966

0

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1967

1

1

1

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1968

0

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1969

1

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

1

 

 

 

 

 

 

 

 

 

 

 

 

1970

3

4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3

4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1971

3

3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

2

 

 

 

 

 

 

 

 

 

 

1

1

 

 

 

 

 

 

1972

45

64

 

 

 

 

 

 

 

 

2

2

 

 

5

6

 

 

33

48

 

 

5

8

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1973

11

11

 

 

 

 

 

 

 

 

2

2

 

 

1

1

 

 

 

 

 

 

1

1

2

2

 

 

 

 

 

 

 

 

 

 

5

5

1974

12

13

 

 

 

 

 

 

 

 

1

1

 

 

5

5

 

 

 

 

 

 

1

2

 

 

 

 

 

 

 

 

 

 

 

 

5

5

1975

24

30

 

 

 

 

 

 

 

 

3

3

 

 

18

23

 

 

2

3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

1

1976

67

205

 

 

 

 

 

 

 

 

1

1

 

 

18

25

 

 

41

170

 

 

 

 

 

 

 

 

 

 

6

8

 

 

1

1

 

 

1977

15

24

 

 

 

 

 

 

1

1

1

1

 

 

1

1

 

 

6

14

 

 

2

2

 

 

1

2

 

 

3

3

 

 

 

 

 

 

1978

57

86

 

 

 

 

 

 

7

7

17

22

 

 

24

42

 

 

7

13

 

 

 

 

 

 

 

 

 

 

2

2

 

 

 

 

 

 

1979

45

131

 

 

 

 

 

 

 

 

 

 

 

 

6

28

1

4

18

29

 

 

 

 

 

 

 

 

 

 

3

4

 

 

 

 

17

66

1980

47

90

 

 

26

34

 

 

1

1

5

5

 

 

1

2

 

 

12

45

 

 

 

 

1

1

1

2

 

 

 

 

 

 

 

 

 

 

1981

14

34

 

 

 

 

 

 

 

 

6

9

 

 

2

3

 

 

5

21

 

 

 

 

 

 

 

 

 

 

1

1

 

 

 

 

 

 

1982

3

3

 

 

 

 

1

1

1

1

1

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1983

23

39

 

 

 

 

2

3

1

1

17

27

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

7

 

 

 

 

1

1

1984

49

130

 

 

 

 

1

2

 

 

14

16

 

 

 

 

1

2

10

74

 

 

4

7

 

 

 

 

1

3

2

2

1

1

15

23

 

 

1985

23

32

 

 

 

 

1

3

 

 

17

24

 

 

3

3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

2

 

 

 

 

 

 

1986

32

50

 

 

 

 

10

11

 

 

14

30

 

 

2

3

 

 

 

 

3

3

 

 

 

 

 

 

 

 

3

3

 

 

 

 

 

 

1987

19

39

 

 

 

 

5

14

 

 

11

17

2

7

 

 

 

 

 

 

1

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1988

40

79

1

1

 

 

 

 

 

 

31

58

1

1

 

 

 

 

 

 

1

2

 

 

 

 

 

 

 

 

1

1

 

 

5

16

 

 

1989

9

17

 

 

1

3

 

 

 

 

3

3

 

 

1

1

 

 

 

 

1

1

 

 

 

 

 

 

 

 

 

 

 

 

3

9

 

 

1990

14

50

 

 

 

 

 

 

 

 

5

9

 

 

1

17

 

 

 

 

 

 

 

 

 

 

2

10

 

 

 

 

 

 

6

14

 

 

1991

12

37

 

 

 

 

 

 

 

 

2

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

10

35

 

 

1992

23

31

 

 

 

 

 

 

 

 

2

5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

21

26

 

 

 

 

 

 

1993

20

32

 

 

 

 

 

 

 

 

20

32

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1994

4

6

 

 

 

 

 

 

 

 

4

6

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Unkn.

1

7

 

 

 

 

 

 

 

 

 

 

 

 

1

1

 

 

1

6

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 4: Distribution by country and year of earthquakes associated with strong-motion recordings (Evt) and the number of recordings (Rec) held on the Imperial College databank.

Year

Total

Alg

Bul

Ger

Gre

Iran

Italy

Por

Rom

Tur

UK

USSR

Yug

Evt

Rec

Evt

Rec

Evt

Rec

Evt

Rec

Evt

Rec

Evt

Rec

Evt

Rec

Evt

Rec

Evt

Rec

Evt

Rec

Evt

Rec

Evt

Rec

Evt

Rec

1969

1

1

1

1

1971

1

1

1

1

1972

28

40

28

40

1973

3

3

2

2

1

1

1974

1

1

1

1

1976

37

140

34

137

2

2

1

1

1977

12

21

1

1

1

1

1

1

6

14

1

2

2

2

1978

18

32

7

7

3

3

1

9

7

13

1979

38

76

18

28

3

4

17

44

1980

35

67

23

28

1

1

10

37

1

1

1981

14

33

6

9

2

3

5

20

1

1

1982

2

2

1

1

1

1

1983

9

14

1

1

1

1

5

7

2

5

1984

17

65

1

1

3

3

10

58

2

2

1

1

1985

5

6

1

1

2

3

2

2

1986

10

13

7

10

3

3

1987

3

4

3

4

1988

18

31

12

14

1

1

5

16

1989

6

14

1

3

2

2

3

9

1990

13

38

4

6

1

8

2

10

6

14

1991

12

37

2

2

10

35

1992

23

31

2

5

21

26

1993

20

32

20

32

1994

4

6

4

6

Unkn.

1

3

1

1

1

2

 

Visual examination of the 2145 component records has shown a number to contain irrecoverable errors such as clipping, missing data segments and very poor quality digitisation. Consequently, the number of usable records is reduced. Furthermore, by taking into consideration the availability of seismological parameters (magnitude and distance) for these records, the available strong-motion data set consists of 598 record sets from 287 earthquakes. This though is independent of local soil conditions, thus by also considering this factor the usable data set is further reduced to 590 record sets from 285 events with a basic soil description and 192 record sets from 102 earthquakes if detailed soil conditions are considered.

These data sets do not consider focal depth. The most common data usage is from crustal earthquakes (< 30km). Therefore the associated data sets of crustal and sub-crustal strong-motion records are summarised in Table 5.

 

Table 5: Numbers of useable earthquakes and associated strong-motion ground-level record sets for the European region as a function of common magnitude and focal depth delimiters.

h>0 km

h£30 km

h>30 km

Soil Excluded

Soil Included

Soil Excluded

Soil Included

Soil Excluded

Soil Included

 

NEQ

NREC

NEQ

NREC

NEQ

NREC

NEQ

NREC

NEQ

NREC

NEQ

NREC

Ms>0

287

598

285

590

275

581

273

574

12

17

12

16

Ms³4

167

437

166

430

158

423

157

417

9

14

9

13

 

It is interesting to note the distribution pattern. Obviously the yearly totals depend on seismic activity, however it is somewhat surprising to see that the totals for the last decade have remained relatively constant and are indeed lower than the mid to late 1970's and early 1980's. This is surprising because the last decade has seen an expansion in strong-motion instrumentation numbers, both on national network scales but also in the proliferation of small local networks. In addition to this, strong-motion instruments have themselves advanced in technology both in quality and ability, specifically with the deployment of digital instruments which allow large numbers of time-histories from small events to be recorded. The TPG have actively sorted to obtain new records thus the low numbers of data for the last decade probably reflects three factors:

These three points must be addressed to enable European earthquake research to advance at the same pace as that in the U.S., Japan and New Zealand. The dissemination of strong-motion data and associated seismological parameters in CD-ROMs or their inclusion on the INTERNET is highly desirable. The experience of the TPG has been with the following CD-ROMs:

The CD-ROM published by the United States Geological Survey (Seekins et al., 1992) contains nearly 1500 strong-motion record sets (mostly triaxial) from about 500 earthquakes in North and Central America and Hawaii between 1933 and 1986 obtained from a variety of agencies. Records are from “ground level” instruments which includes “free-field” sites and instruments in basement and ground floor locations of structures. All records are written into a uniform file format. Data base index files containing summary information for each record are included. A data base search programme is also included to allow the user to search on a variety of parameters.

The CD-ROM published by the Russian Academy of Sciences and the National Oceanic and Atmospheric Administration in collaboration with Joint Institute of the Physics of the Earth (Sobolev et al., 1994) contains 149 triaxial record sets from the aftershock sequence of the 1988 Spitak, Armenia earthquake. Two data sets are incorporated; recordings from instruments installed by the Russian field team, IPEM (25 sets) and from instruments installed by the USGS team (124 sets). Each data set is written to a uniform file format. Two data base programs are supplied; the NOAA GeoVu facility and a RAS Spitak specific program (SDBS).

The CD-ROM published by the National Oceanic and Atmospheric Administration/National Geophysical Data Center (NGDC, 1996) contains more than 15,000 processed accelerograph records comprising uncorrected and corrected acceleration time histories, response and Fourier spectra, as well as velocity and displacement time histories. Records have been contributed from a number of world-wide agencies. File formats are non-uniform remaining in the format of the contributory agency. The data base program SMCAT3 is included.

The 3 volume CD-ROM set published by the Strong-Motion Earthquake Observation Council in Japan (AEDP, 1994) contains over 12,000 records from events in the period 1974-1993. Records are from a variety of networks in Japan including down-hole arrays and instrumented structures. A data base program is included.

The CD-ROM published by the Institute of Engineering Seismology & Earthquake Engineering in Thessaloniki (ITSAK, 1997) contains 126 uncorrected and corrected acceleration time histories, as well as velocity and displacement histories recorded between 1980 and 1994 by its SMA-1 network installed throughout Greece. The individual data were corrected using three different processing procedures.

The CD-ROM published by the Sociedad Mexicana de Ingenieria Sismica, A.C. (SMI, 1997) provides informations about strong earthquakes in Central America as well as listings with waveform-parameters of the acceleration time histories recorded by strong motion stations installed all over Mexico and operated by different agencies, institutions and companies. A limited number of digitised time histories are available on the CD-ROM.

The CD-ROM published by the Servizio Sismico Nazionale (SSN) and Ente Nazionale per l'Energia Ellettrica (ENEL), both agencies are located in Rome (SSN/ENEL, 1998), contains 99 uncorrected acceleration time histories from the Umbro-Marchigiana earthquake sequence of September and October 1997. They all were recorded with the SSN and ENEL analogue and digital accelerograph network. The reported moment magnitude (Mw) of the data set ranges from 5.4 to 6.0 and the epicentral distance from 3km to 128km.

 

In addition to these CD-ROMs, the TPG have also received large volumes of data via DAT and Exabyte cartridges, specifically data from the Taiwanese SMART-1 array and the Japanese CHIBA array. Whilst the availability of data via such mass media is extremely valuable, it must be recognised that use of this data cannot be made indiscriminately. Such large data bases and data sets will inevitably contain errors and/or be incomplete.

For example, the USGS CD-ROM, as mentioned, contains data base summary files to facilitate end users writing record identification programs to prepare data listings for their use. These summary files have however been found to contain a number of errors; misassociation of records with stations and events, incorrect file names, incorrect and inconsistent station names. Furthermore, the data base information cannot itself be considered wholly accurate; magnitude and distance data have where available been taken from Joyner and Boore (1981), but which has subsequently been updated by Boore et al. (1993, 1994); magnitude and distance data contained in the record files can vary with the source (the agency) of the record; distances calculated from given magnitude and station coordinates do not agree with the given distance; instrument parameters given in the files do not necessarily agree with cited references. It required one man-year of effort to transform all the data held on this CD-ROM to a form usable by TPG. It should be noted that whilst the USGS include a suitably worded disclaimer this will not prevent users employing data from the CD-ROM incorrectly.

The Spitak CD-ROM was similarly found to be of limited use, the primary problem being that the CD-ROM eliminated critical information provided with the original USGS data set (Borcherdt, et al.,1989; Filson, et al.,1989). The CD-ROM includes values that have not been translated precisely.

The original data were recorded on six channel General Earthquake Observation Systems (GEOS) developed by the USGS (Borcherdt, et al.,1985). Critical original GEOS recording parameters found to be missing from the header information of the CD-ROM (Borcherdt and Glassmoyer, pers. comm., 1997) are digitisation constant and amplifier gain. These parameters are needed to convert digital values on the CD-ROM to ground motion. The coil constant (sensor sensitivity), although included in the sensor parameters displayed during the menu selection, is not included in either the export or the plot display of the CD-ROM data. Also the null value, that represents data gaps that occur within the KIR records, has not been accounted for on the Spitak Earthquake CD-ROM correctly, so plots of these records are not valid. Additional original information not included on the CD-ROM are: time of the recording (including clock correction), event number and recorder serial number (not necessarily needed by all users), station elevation, anti-aliasing corner frequency and roll-off, and exact integer value for 1, which has been translated to 0.9992335.

In order to use the data on the CD-ROM, the user must convert the digital values to ground motion. This conversion can be accomplished by dividing the digital value on the CD-ROM by the digitisation constant (3276.8 counts/volt for the GEOS), the coil constant (0.0051 volts per cm-per-second-squared for an FBA), and the amplifier gain specified in 6 dB steps. The digitisation constant and coil constant are the same for all GEOS data included on the Spitak Earthquake CD-ROM, however the amplifier gains vary from 6 dB to 18 dB. For the data recorded at the ART, DZH, GIB, GOG, KIR, KI2 and NAB sites with an amplifier gain of 6 dB the ground motion in cm/sec2 can be obtained by dividing the digital counts on the CD-ROM by 33.4. For the data recorded with an amplifier gain of 12 dB at the BYR, KET, MOO, M02 and STE sites and at the LEN site before 28 December 1988 15:10 UTC the divisor is 66.8. The divisor for the LEN data after 28 December 1988 15:10 UTC and all of the GSS data recorded at 18 dB is 133.7. Original USGS null values of -32768 on some of the KIR records were translated incorrectly as -3.274114e+04.

The original USGS GEOS data for the 124 acceleration records included on the Spitak Earthquake CD-ROM are available at http://agram.wr.usgs.gov/GEOS/geos.html. In addition, the entire and much larger data set, including 2000 separate recordings from velocity sensors as well as additional FBA recordings of the Spitak aftershock sequence also are available at this site.

Limited use has been made of the NOAA/NGDC CD-ROM to date; however serious shortcomings are apparent. Obviously the presentation of records in a non-uniform file format makes it difficult to write programmes which use large volumes of records from a variety of sources. Errors have been found in the database, in particular the misassociation of database fields with the result that different search patterns, which should produce the same results, do not. Furthermore, errors in records, including those obtained from TPG and other agencies have been found which can be sourced to the contributory organisation but which should have been identified with a simple check prior to their inclusion on the CD-ROM.

We have made no use as yet of the Japanese CD-ROM set. Use of this data is restricted by the requirement to convert all magnitudes from JMA scale, particularly for the smaller values if they are to be compared with European, or indeed with any other world-wide data. The potential for errors within such mass media data sets has been recognised by the Japanese who include an error report form in the user manual to allow end-users to pass back to the Strong-Motion Council the errors they identify.

It must be emphasised that the above description of problems in the CD-ROMs is not intended necessarily as a criticism of the product or the publishing organisation. With our TPG programme we are fully aware of data base errors and completeness. In particular, our most recent research efforts made extensive use of our data base and data bank and highlighted a number of significant errors similar to those described above. Quite simply, it is not easy, or economical, to produce a reliable data bank in this form. In the case of the TPG errors, their origin resulted from two factors: data operator input errors and errors in data supplied by the contributory organisation. Despite the clean-up associated with the above, we still fully expect to find further errors in our data base and data bank in future work.

From the foregoing, it is readily apparent that although there is a great need for data storage and dissemination on a European and World level, and that CD-ROMs can provide the uninitiated engineer with readily available strong-motion time-histories, the indiscriminate use of the data in existing CD-ROMs is likely to generate erroneous and misleading results. The derivation of attenuation laws and site-specific design parameters must rely on good quality databases and reliable associated data banks rather than on statistics of many records of questionable quality, Boore and Ambraseys (1993).

With very few exceptions the terms of reference of most of the strong-motion networks in Europe include little more than what is needed to keep them going and much of the data they acquire are not freely available to end-users such as young researchers, engineers or earth scientists and as a result relatively little research is generated. This inaccessibility of the available strong-motion records from a wide variety of well-recorded earthquakes has been having a major impact on the research and development of strong-motion studies in Europe and has created a serious imbalance of knowledge. Theoretical methods for the prediction of ground motions have become highly developed, whilst knowledge of the observational material, the strong-motion records proper that can provide the acid test to these theories and models, is restricted and kept at a primitive stage. Of course, this is not a problem unique to Europe and steps have already been taken by a number of European networks to release their strong-motion data on CD-ROMs.

8. Future activities of TG2

Regarding to the feedback and the comments to our questionnaire we have sent to different European data centres and institutions, the main activity that TG2 might support in the future, will be the establishment of an INTERNET site in which (contributing) agencies could deposit free-field strong-motion data from the European area and other information regarding research and development in this field for free use by the profession. This TG2 site will be developed in two stages:

In the first stage, access to the site will have only those who will be contributing to its initial generation. During this stage a databank and database of about 1,000 uncorrected triaxial strong motion records which are now processed jointly by ENEA/ENEL (Rome), IPCG/CEA (Paris) and ICSTM (London) will be included in the INTERNET site in stages. The site will be operated jointly by Drs, R. Berardi, D. Rinaldis, Ch. Gariel and P. Smit.

In the second stage, the INTERNET site will be extended allowing interactive downloading and depositing of strong motion data and other information. The site will then be opened to the public domain with identical sites (mirroring) in Rome, Paris and London.

We envisage that stage (1) will be completed by the end of 1999, and stage (2) a year later.

REFERENCES

AEDP (1994), “Strong motion array record database”, Advisory and Database Operation Committee, Association for Earthquake Disaster Prevention

Ambraseys N. (1995), “The prediction of earthquake peak ground acceleration in Europe”, J. Earthq. Eng. & Str. Dyn., vol.24, pp.467-490

Ambraseys N., Bommer J. (1991), “The attenuation of ground accelerations in Europe”, J. Earthq. Eng. & Str. Dyn., vol.20, pp.1179-1202

Ambraseys N., Simpson K., Bommer J. (1996), “Prediction of horizontal response spectra in Europe”, J. Earthq. Eng. & Struct. Dyn., vol.25, pp.371-400, & vol.26, pp.295-301 (1997)

Ambraseys N., Bommer J. (1995), “Attenuation relations for use in Europe; an overview”, Proc. Seism. Design Pract., pp.67-74, Chester, Balkema

Ambraseys N., Simpson K. (1996), “Prediction of vertical response spectra in Europe”, J. Earthq. Eng. & Str. Dyn., vol.25, pp.401-412

Ambraseys N., Free M. (1997), “Surface-wave magnitude calibration for European region earthquakes”, J. Earthq. Eng., vol.1, pp.1-22

Boore D., Ambraseys N. (1993), “Some notes concerning prediction of ground motions for GSHAP”, Ann. Geofis., vol.36, pp. 169-180

Boore D., Joyner W., Fumal T. (1993), “Estimation of response spectra and peak accelerations from western north American earthquakes: an interim report”, U.S. Geological Survey Open-File Report 93-509, 72pp

Boore D., Joyner W., Fumal T. (1994), “Estimation of response spectra and peak accelerations from western north American earthquakes: an interim report, part 2”, U.S. Geological Survey Open-File Report 94-127, 40pp

Borcherdt R., Fletcher J., Jensen E., Maxwell G., Van-Schaack J., Warrick R., Cranswick E., Johnston M., McClearn R. (1985), “A general earthquake observation system (GEOS)”, Bull. Seism. Soc. Am., vol. 75, p.1783-1825

Borcherdt R., ed. (1989), “Results and data from seismological and geologic studies of the earthquakes of December 7,1988 near Spitak, Armenia, U.S.S.R.”, U.S. Geological Survey Open-File Report 89-163, v. I, II, III, IV, V, 958 p

Caillot V., Bard P-Y. (1993), “Magnitude, distance and site dependent spectra from Italian accelerometric data”, J. Eur. Earthq. Eng., vol.7, pp.37-48

Chiaruttini C., Siro L. (1981), “The correlation of peak ground horizontal acceleration with magnitude, distance and seismic intensity for Friuli and Ancona, Italy, and the Alpide Belt”, Bull. Seism. Soc. Am., vol.71, pp.1993-2009

Filson J., Borcherdt R., Langer C., Simpson D. (1989), “Seismology”, in Wyllie, Jr., L.A., and Filson, J.R., eds., Armenian Earthquake, Earthquake Spectra, Special Supplement, August, 175 pp

ITSAK (1997), “Selected strong motion acceleration time histories from the ITSAK network”, Institute of Engineering Seismology and Earthquake Engineering, Thessaloniki

Joyner W., Boore D. (1981), “Peak horizontal acceleration and velocity from strong-motion records including records from the 1979 Imperial Valley, California earthquake”, Bull. Seism. Soc. Am., vol.71, pp.2011-2038

Inan E., Çolakoðlu Z. et al. (1996), “Catalog of earth-quakes between 1976 and 1996 with acceleration record”, Publ. Deprem Arast. Dairesi Baþ., Bayýndýrlýk & Iskan Bak., Ankara

Lee, V. (1995), “Pseudo relative velocity spectra in former Yugoslavia”, J. Eur. Earthq. Eng., vol. 9, pp.12-22

Mohammadioun, B. (1991), “The prediction of response spectra for the anti-seismic design of structures specificity of data from intracontinental environments”, J. Eur. Earthq. Eng., vol 5, No.2, pp. 8-19

NGDC (1996), “Earthquake strong motion”, National Geophysical Data Center Earthquake Strong Motion 3-Volume CD-ROM Collection

Petrovski D., Marcellini A. (1988), “Prediction of seismic movement of a site: statistical approach”, Proc. UN Sem. on Predict. of Earthq., Lisbon,

Petrovski J. et al. (1994), “Characteristics of earthquake ground motions obtained on the Ohrid lake three dimensional strong motion array in the Republic of Macedonia”, Proc. 10th Euro. Conf. Earthq. Eng., Vienna

Pugliese A., Sabetta F. (1989), “Stima di spettri di risposta da registrazioni di forti terremoti italiani”, Ingegneria Sismica, vol 6, No.2, pp. 3-14 [in Italian]

Sabetta F., Pugliese A. (1987), “Attenuation of peak horizontal acceleration and velocity from Italian strong-motion records”, Bull. Seism. Soc. Am., vol.77, pp.1491-1513

Seekins L., Brady G., Carpenter C., Brown N. (1992), “Digitised strong-motion accelerograms from North and Central American earthquakes 1933-1986”, U.S. Geological Survey Digital Data Series DDS-7

SMI (1997), “Base Mexicana de Datos de Sismos Fuertes, Volumen 1”, Sociedad Mexicana de Ingenieria Sismica, A.C., Mexico DF

Smit P. (1998), “The Swiss national strong motion network–Achievement and Prospect”, Proc. 11th Europ. Conf. Earthq. Eng., Paris, 6-11 September

Sobolev G., Tyupkin Yu., Frolov I., Sergeeva N., Arefev S., Govorov A., Rogozhin E., Tatevasyan R., Zhizhin M., Schukin Yu., Lockridge P., Habermann R., Whiteside L., Hittelman A.,Meyers H., Malitkzy A. (1994), “Spitak earthquake-December 7, 1988”, Russian Academy of Sciences and the National Oceanic and Atmospheric Administration in collaboration with Joint Institute of the Physics of the Earth

SSN/ENEL (1998), “Elaborazioni delle Principali Registrazioni Accelerometriche della Sequenza Sismica Umbro-Marchigiana del Settembre Ottobre 1997”, Servizio Sismico Nazionale (SSN), Ente Nazionale per l'Energia Ellettrica (ENEL), Rome

Tento A., Franceschina L., Marcellini A. (1992), “Expected ground motion evaluation for Italian sites”, 10th World Conf. Earthq. Eng., vol.1, pp.489-494, Madrid

Theodulidis N., Papazachos B. (1992), “Dependence of strong ground motion on magnitude-distance, site geology and macroseismic intensity for shallow earthquakes in Greece I: peak horizontal acceleration, velocity and displacement”, H. Soil Dyn. & Earthq. Eng., vol.11, pp.387-402

European Strong-Motion Agencies

Albania

Prof. Dr. Siasi Kociu *

Seismological Institute, Academy of Sciences of Albania, Tirana

Tel:+355 422 82 74; Fax: +355 422 82 74, E-Mail: kociu@sizmo.tirana.al

Remarks: Seismic networks

Algeria

Dr. Dj. Benouar *

Institute de Génie Civil, Université Houari Boumediene, P.O. Box 32

Al-Alia, Bab Ezzouar

Tel: +213 251 55 75; Fax: +213 250 82 03

Remarks: Strong-motion network

Dr. M. Belazoughi

Centre de Recherche de Génie Sismique (CGS), 1 rue Kaddour Rahim, Hussein-Dey

Fax: +213 277 66 56

Armenia

Prof. Dr. Sergey Balassanian

National Survey for Seismic Protection of the Republic of Armenia

Davidashen-Massiv 4, 375054 Yerevan

Tel: +374 228 28 11; Fax: +374 215 11 08, E-Mail: presidnt@nssp.yerphi.am

Remarks: Seismic networks

Austria

Dr. Niklaus Horn

Zentralanstalt für Meteorologie und Geodynamik (ZAMG), Hohe Warte 38; 1190 Wien

Tel: +43 1 360 26 25 01; Fax: +43 1 368 66 21, E-Mail: seismo@zagsun2.zamg.ac.at

Remarks: Strong-motion network

Mr Bernhard Kofler

Tauernkraft, Postfach 41, 5710 Kaprun

Tel:+43 6547 71513243; Fax:+43 65477154 3250

Remarks: Several dam-related strong-motion arrays in the Tauern area (Eastern Alps)

Belgium

Dr. Th. Camelbeeck *

Observatoire Royal de Belgique, Avenue Circulaire 3, 1180 Bruxelles

Tel: +322 373 02 52; Fax: +322 373 03 39, E-Mail: camelbeeck@oam.be

Remarks: Seismic networks

Bulgaria

Dr. Ivanka Paskaleva *

Central Laboratory of Seismic Mechanics (CLSM), Acad. G. Bonchev, Ul. Bl. 3, 1113 Sofia

Tel: +3592 971 24 07; Fax: +3592 971 24 07

Remarks: Seismic networks

Croatia

Dr. Ivo Allegretti

University of Zagreb, Faculty of Sciences, Geophysical Department, Horvatovac, 10000 Zagreb

Tel: +385 142 03 22; Fax: +385 143 24 62

Remarks: Seismic networks

Egypt

Dr. M.M. Dessokey

National Research Institute of Astronomy & Geophysics, Seismological Observatory Helwan, Cairo

Remarks: Seismic networks

Finland

Prof. Dr. U. Luosto

University of Helsinki, Institute of Seismology, Et. Hesperiankatu 4, 00014 Helsinki

Tel: +358 01 91 72 88

Remarks: Seismic networks

France

Prof. Dr. Uli Achauer

Réseau National de Surveillance Sismique, EOPG, Rue Rene Descartes 5, 67084 Strasbourg Cedex

Tel: +338 841 66 51; Fax: +338 861 67 47, E-Mail: renass@ctds.u-strasbg.fr

Remarks: Seismic networks & strong-motion network in the Ober-Rhinegraben area

Dr. Myriam Bour

Bureau de Recherches Géologiques et Minières

SGN/UPE/RNG, 117 Avenue de Luminy, 13276 Marseille Cedex 09

Tel: +33 491 17 74 74; Fax: +33 491 17 74 75, E-Mail: m.bour@brgm.fr

Remarks: Seismic networks in Southern France and Guadeloupe (French West Indies)

Dr. Denis Hatzfeld

Laboratoire Central des Ponts-et-Chaussées et Observatoire de Grenoble, LGIT/IRIGM, P.O. Box 53 X, 38041 Grenoble Cedex

Tel: +33 476 51 49 22; Fax: +33 476 51 44 22, E-Mail: hatzfeld@lgit.observ-gr.fr

Remarks: Strong-motion network

Dr. Bagher Mohammadioun *

Institut de Protéction et de sûrété nucléaire, Département de protéction de l'environnement et des installations BERSSIN, CE-FAR 60-68, Avenue du Général Leclerc 60-68, P.O. Box 6, 92265 Fontenay aux Roses Cedex

Tel: +33 1 46 54 74 12; Fax: +33 1 46 54 81 30, E-Mail: mohammadib@basilic.cea.fr

Remarks: Seismic networks

Septen, Electricité de France

Div. Mechan. Struct., Avenue de Dutrievoz 12, 69628 Villerbanne Cedex, Tel: +33 472 82 75 54

Remarks: Several strong-motion arrays in French nuclear power plants

Georgia

Dr. Zurab Javakhishvili

Institute of Geophysics, Georgian Academy of Sciences, M. Aleksidze Street 1, 380093 Tbilisi

Tel: +995 32 36 54 80; Fax: +995 32 94 28 61, E-Mail: root@geophy.acnet.ge

Remarks: Strong-motion network & dam-related array in the Inguri arch dam

Germany

Dr. H. Aichele

Bundesanstalt für Geowissenschaften und Rohstoffe, Seismologisches Zentralobservatorium Erlangen, Krankenhausstrasse 1, 91054 Erlangen

Tel: +49 913 125 900; Fax: +41 913 124 078

Remarks: Gräfenberg array

Dr. Wolfgang Brüstle

Landes Erdbebendienst Baden Württemberg (LED), Albertstrasse 5, 79104 Freiburg im Breisgau

Tel: +49 761 204 44 34; Fax: +49 761 204 44 38, E-Mail: bruestle@glas0.gla.uni-freiburg.de

Remarks: Seismic networks in southern Germany an the Ober-Rhinegraben area

Dr. Klaus Günter Hinzen

Erdbebenstation Bensberg

Vinzenz Pallotti Strasse 26, 51429 Bergisch Gladbach

Tel: +49 22 048 1343; Fax: +49 22 048 5043, E-Mail: adg11@rs1.rrz.uni-koeln.de

Remarks: Seismic networks in northwestern Germany

Greece

Prof. Dr. K. Makropoulus

University of Athens (UA), Seismological Laboratory, Panepistimioupolis Illissia, 15789 Athens,

Tel: +301 724 32 17

Remarks: Strong motion network in the Patras

Dr. B.N. Margaris *

Institute of Engineering Seismology & Earthquake Engineering (ITSAK)

46 Georgikis Scholis Street, P.O. Box 53, 55101 Thessaloniki Finikas

Tel: +30 147 60 81, Fax: +30 147 60 85, E-Mail: margaris@quake.itsak.gr

Remarks: ITSAK strong-motion

Prof. Dr. K. Pitilakis

Aristotle University, Department of Civil Engineering, 54006 Thessaloniki

Tel: +303 199 56 93; Fax: +303 120 61 38

Mr K. Scourtis

Public Power Corporation (PPC), 41 Solomou Street, 10682 Athens

Tel: +301 300 138 10 61; Fax: +301 380 71 28

Dr. G. Stavrakakis *

National Observatory of Athens (NOA), Geodynamic Institute, P.O. Box 20048, 11810 Athens

Tel: +30 1 346 26 64; Fax: +30 1 342 60 05, E-Mail: g.stavr@egelados.gein.noa.gr

Hungary

GeoRisk (GR)

Geophysical Research and Consulting Ltd., Ringló u. 101B, 1221 Budapest

Tel: +36 1 3193382; Fax: +36 1 2264573, E-Mail: georisk@seismology.hu

Remarks: Seismic networks

Iceland

Prof. R. Sigbjörnsson *

University of Iceland (UI), Engineering Research Institute, Applied Mechanics Laboratory, Hjardarhagi 2-6, 107 Reykjavik

Tel: +354 525 49 19; Fax: +354 525 49 13, E-Mail: ragnarz@afl.hi.is

Remarks: Strong-motion network

India

Dr. Imtiyaz Ahmed Parvez

Department of Geophysics, Banaras Hindu University, 221005 Varanasi

Tel: +91 542 31 62 09; Fax: +91 542 31 70 74, E-Mail: aram@banaras.ernet.in

Remarks: Strong-motion network

Dr. B.K. Rastogi

National Geophysical Institute, Council of Scientific & Industrial Research, 500007 Hyderabad

Tel: +91 40 670 14 1-9; Fax: +91 40 671 564, E-Mail: postmast@ngri.uunet.in

Remarks: Dam-related array in the Koyna-dam

Iran

Dr. M. Ahmadi

Building & Housing Research Centre (BHRC), P.O. Box 13145-1696, Tehran

Tel: +9821 985 59 42;

Remarks: Strong-motion network

Dr. M. Ghafory-Ashtiany

International Institute of Earthquake Engineering (IIEES), P.O. Box 19395-3913, Tehran

Tel: +982 127 54 84; Fax: +952 143 787 32, E-Mail: iees@irearn.bitnet

Remarks: Seismic network

Dr. Ali Moinfar *

#D2 Nowar 6th Street, Farnaz Mohseni Square, Mirdamad Tehran

Tel: +98 212 22 78 08, E-Mail: moinfar@istn.irost.com

Israel

Dr. Avi Shapira

Institute of Petroleum Research & Geophysics, Seismological Division (IPRG)

1 Ha'Mashbir Street, P.O.Box 2286, 58122 Holon

Tel: +972 355 760 50; Fax: +972 355 029 27, E-Mail: seis@iprg.energy.gov.il

Remarks: Seismic networks

Italy

Dr. Raniero Berardi

ENEL Società per Azioni (ENEL), Direzione Costruzioni, Unita Siti e Ambiente

Vile Regina Margerita 137, 00198 Rome

Tel: +390 685 39 85 94; Fax: +390 685 39 27 36, E-Mail: paladina_marina.co.dg@mailbox.enel.it

Remarks: Strong-motion network

Dr. P. Capocecera

ENEA Centro Ricerche Casaccia (ENEA), Div. Caratterizzazione Ambiente e Territorio, Dipartimento Ambiente, Sezione Dinamiche Geologiche e Territorio

Via Anguillarese 301, 00100 Rome

Tel: +390 630 48 43 44; Fax: +390 630 48 48 72, E-Mail: utente@sunrin.casaccia.enea.it

Dr. Giovanni Costa

Universita degli studi di Trieste (TRI), Dipartimento di scienze della terra

Via E.Weiss 1, 34127 Trieste

Tel: +390 40 676 21 24; Fax: +390 40 676 21 11, E-Mail: costa@geosun0.univ.trieste.it

Remarks: Strong-motion network in the epicentral area of the 1976 Friuli earthquake

Dr. Dario Slejko

Observatorio Geofisico Sperimentale, P.O. Box 2011 (Opicina), 34016 Trieste

Tel: +390 4 021 401; Fax: +390 4 032 73 07, E-Mail: dslejko@ogs.trieste.it

Remarks: Seismic networks in northern Italy

Dr. G. Smriglio

Istituto Nazionale di Geofisica, Sezione Dati Sismici, Via di Vigna Murata 605, 00143 Rome

Tel: +390 651 86 01; Fax: +390 650 411 81, E-Mail: smriglio@in8800.ingrm.it

Remarks: Seismic networks

Dr. Dario Rinaldis *

ENEA Centro Ricerche Casaccia, Div. Caratterizzazione Ambiente e Territorio

Dipartimento Ambiente, Sezione Dinamiche Geologiche e Territorio

Via Anguillarese 301, 00100 Rome

Tel: +390 630 48 43 44; Fax: +390 630 48 48 72, E-Mail: utente@sunrin.casaccia.enea.it

Macedonia

Prof. Dr. V. Mihailov

University Kiril and Metodij, Institute of Earthquake Engineering, 73 Salvador Allende Street, P.O. Box 101, 91000 Skopje

Fax: +389 911 121 63, E-Mail: mihailov@pluto.iziis.ukim.edu.mk

Prof. J. Petrovski *

51 Helsinki Street (IZIIS), 91000 Skopje

Tel: +389 91 36 31 02, E-Mail: jakimtp@nic.mpt.com.mk

Remarks: Strong-motion network

Morocco

Prof. Dr. D. Ben Sari

Centre National de Coordination et de Planification de la Recherche Scientifique et Technique (CNC), 52 Charia Omar Ibn Khattab, Agdal, P.O. Box 8027, 32072 Rabat

Tel: +212 777 28 03; Fax: +212 777 86 78

Remarks: Seismic networks

Netherlands

Dr. Reinoud Sleeman

Royal Netherlands Meteorological Institute, Division of Seismology (RNMI)

P.O. Box 201, 3730 De Bilt

Tel: +31 30 205 911; Fax: +31 30 210 407, E-Mail: sleeman@knmi.nl

Remarks: Seismic networks

Norway

Dr. H. Bungum

NORSAR (NORSAR), Ganavelen 33, P.O. Box 51, 2007 Kjeller

Tel: +47 688 171 21; Fax: +47 688 187 19

Remarks: NORSAR array

Pakistan

Mr Altaf Ur Rahman

NESPAK, 1-C Block-N, Model Town Extension, Lahore

Portugal

Prof. Carlos Sousa Oliveira *

Instituto Superior Tecnico (IST), Departmento Engenharia Civil, Av. Rovisco Pais, Lisabon Codex

Tel: +351 1 841 82 01; Fax: +351 1 849 76 50, E-Mail: csoliv@civil.ist.utl.pt

Remarks: Strong-motion network

Russia

Dr. Sergej Arefiev

Institute Physics of the Earth, Russian Academy of Sciences, B.Gruzinskaya 10, 123810 Moskau

Tel: +7 95 254 53 16; Fax: +7 95 254 90 88, E-Mail: arefiev@synapse.ru

Remarks: Head of the strong-motion group of the Academy in Moscow

Slovak Republic

Mr Ladislav Cocher

Bohunice Nuclear Power Plant, 91931 Jslovske-Bohunice, Tel: +42 805 2130104

Remarks: Strong motion array in the Bohunice nuclear power Plant

Slovenia

Dr. J.K. Lapajne *

Geophysical Survey of Slovenia (GSS), Kersnikova 3, 1000 Ljubljana

Tel: +386 61 132 62 84; Fax: +386 61 132 70 67, E-Mail: janez@gf.sigov.mail.si

Remarks: Strong-motion network

Spain

Dr. Emilio Carreno Herrero

Ministerio de Obras Publicas, Direccion General del Instituto Geografico National (IGN), General Ibanez de Ibero 3, 28003 Madrid

Tel: +34 1 91 597 97 58; Fax: +34 1 91 597 95 09, E-Mail: emilio@geo.igns.es

Remarks: Strong-motion network

Dr. J. Morales

Instituto Andaluz de Geologia Mediterranea, Apartado, 18080 Granada

Remarks: Seismic networks in southern Spain

Switzerland

Prof. Dr. Domenico Giardini

Institute of Geophysics, Swiss Seismological Service (SSS)

ETH Hönggerberg, 8093 Zürich

Tel: +41 1 633 26 58; Fax: +41 1 633 10 65, E-Mail: giardini@seismo.ifg.ethz.ch

Remarks: Seismic networks

Tunusia

Dr. M. Hfaiedh

Institut national de la Météorologie (INM), Département de Géophysique

P.O. Box 156, 2035 Tunis-Carthage

Tel: +216 1 782 400; Fax: +216 1 784 608, E-Mail: hfaiedh@hp_meteo.inm.tn

Remarks: Seismic networks

Turkey

Deprem Araþtýrma Dairesi

Afet Iþleri Genel Müdürlüðü (DAD), P.K. 763 Kýzýlay, Ankara, Fax: +904 287 36 42

Remarks: Strong-motion network

Prof. Dr. Haluk Eyidoðan

Mining Faculty, Department of Geophysics, Istanbul Technical University, 80626 Maslak Istanbul

Tel: +90 212 285 62 00; Fax: +90 212 285 62 01, E-Mail: eyidogan@sariyer.cc.itu.edu.tr

Remarks: Strong-motion network in the Bursa area (western Turkey)

Dr. Aydýn Mert

Boðaziçi University, Kandilli Observatory Istanbul

Department of Earthquake Engineering, 81220 Cengelkoy-Istanbul

Tel: +90 216 308 05 11, Fax: +90 216 308 01 63

Remarks: Seismic networks in western Turkey

Prof.Dr. H. Sucuoðlu *

Middle East Technical University, Department of Civil Engineering, Earthquake Engineering Research Center, 06531 Ankara

Tel: +90 312 210 54 78; Fax: +90 312 210 13 28, E-Mail: eerc@rorqual.cc.metu.edu.tr

United Kingdom

Prof. Dr. N.N. Ambraseys *

Imperial College of Science Technology and Medicine, Department of Civil Engineering, ESEE Section

Imperial College Road, SW72BU London

Tel:+44 0171 594 6059; Fax: +44 0171 594 60 53, E-Mail: n.ambraseys@ic.ac.uk

Remarks: Convenor of TG2

Dr. Patrick Smit *

Imperial College of Science Technology and Medicine, Department of Civil Engineering, ESEE Section

Imperial College Road, SW7 2BU London

Tel: +44 171 594 61 12; Fax: +44 171 594 60 53, E-Mail: p.smit@ic.ac.uk

Remarks: Secretary of TG2

Convenor: Prof. Dr. N.N. Ambraseys

Secretary: Dr. P.M. Smit