Seismic Network in Sri Lanka IRIS workshop on

Seismic Network in Sri Lanka IRIS workshop on “Managing Waveform Data and Related Metadata from Seismic Networks” Hotel Windsor Suites, Bangkok, Thailand 08 -13, January, 2012 Ashvin Wickramasooriya Senior Lecturer in Earth Science South Eastern University of Sri Lanka

CONTENTS OVERVIEW SRI LANKAN SEISMIC NETWORK SOUTH EAST SEISMIC STATION SPECIFICATIONS: SENSORS/LOGGER/SOFTWARE

Overview There was no seismic network system for Sri Lanka before 2005 However, a single seismic station was established in 1996 under the Global Seismic Network (GSN) at Pallekale, Kandy First Sri Lankan Seismic Network has established in June, 2005 funded by the Japanese Government (JICA)

Initial Plan of establishing this seismic network include : 1) Detect a domestic earthquake and calculate Epicenter and Magnitude 2) Post processing function 3) Data communication: Telephone Line (Dial up) (To reduce the running cost) 4) Four Seismic Stations (To calculate Epicenter)

SRI LANKAN SEISMIC NETWORK There are four seismic stations were established under this network at four universities. Local station(RJR) Rajarata Univ. Central Station (PRD) Peradeniya Univ. Local station(RHN) Ruhuna Univ. Local station(EST) South-East Univ. June , 2005 Funded by JICA

Overview (Function) 1) Continuous Data recording (6 ch, one month) 6 ch: Acceleration 3 ch, Velocity 3 ch 2) Automatic Trigger Function and Call to Central Station (Peradeniya) 3) Automatic Data correction from Central Station to Local Station (Manual correction is also Available) 4) Automatic Processing Function (SEISAN) Epicenter(Domestic) , Magnitude 5) Post Processing Function (SEISAN)

Central Station TCP/IP Protocol Converter Short period seismometer UNIV. LAN Computer Data Logger Hub (6 ch) Forcebaranse servo accelerometer UPS Router with GPS Concrete Base Outside Personal Modem Printer Inside Telephone Line RAJ RHN (Peradeniya) Software for Central Station Data Collection from each stations Data Storage Data Analysis *Epicenter *Magnitude *Spectrum etc Maintenance (Each station ) SET

Local Stations (Rajarata, Ruhuna, South-Eastern) TCP/IP Protocol Converter Short period seismometer Personal Computer Data Logger Hub (6 ch) Forcebalance servo accelerometer Concrete Base Outside UPS Router with GPS Software for Local station Data Collection (Own site, Manual) Data Storage (Do) Maintenance (Own site) Modem Printer Inside Telephone Line Central Station

SOUTH EAST SEISMIC STATION 1. Sensor: 1)Forcebalance Servo Accelerometer : Episensor 2)Seismometer (1 Hz Geophone): GS-1 2. Data Logger: 24 bit Data Logger : Altus K 2 3. Data Acquisition: PC Based System : Recording: SMARTS Processing: SEISAN 4. Communication: Telephone line (Analog, Dial-up)

Sensors Seismometer GS-1 • Epi-sensor • GS-1 Accelerometer Episensor Suitable for Strong motion Suitable for Micro-seismic

Data logger

Site Installation Data Processing system Installation

Resolution & Dynamic Range • Full scale of K 2 : 2. 5 V • A/D resolution : 2. 5 V/223 = 0. 298 micro. V • Acceleration: (0. 23 mgal) – 1960 gal – Effective resolution: 10 mgal ? • Velocity: (0. 0745 microkine) – 625 mkine – Effective resolution: 10 microkine? • GS-1 for small earthquake • Epi-sensor for strong motion

Software configuration Local Stations Central Station

Thank You