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34510-345811
(was 1405)
Observatorio Vulcanológico y Sismológico de Costa Rica
Universidad Nacional (OVSICORI-UNA)
Apartado Postal: 2346-3000
Heredia
Costa Rica


Telephone : (506) 261 0781; 261 0611
Telefax : (506) 261 0303
Director: Dr. Eduardo Malavassi
Email : ovsicori@irazu.una.ac.cr
Website :

www.ovsicori.una.ac.cr
www.una.ac.cr/ovsi

Faculty and staff:

Ana Arquedas - Reception
Vilma Barboza - Volcanic seismology
Jorge Brenes - Geology-volcanic hazards
Zaida Campos - Receptionist
Eliécar Duarte - Volcanology
Erick Fernández - Geochemistry
Victor González - Seismology, computer
Frederico Guendel - Seismology
Enrique Hernandez - Geodesy, deformation
Eduardo Malavassi - Petrology, volcanic hazards, deformation
Tomas Marino - Geodesy, deformation
Maria Martinez - Geochemistry
Antonio Mata - Electronics
Ghisselle Monge - Secretary
Carlos Montero - Seismology
Jorge M. Protti - Seismology, tectonics
Daniel Rojas - Electronics
Rodrigo Sáenz - Volcanology
Juan Segura - Seismology
Yadira Solís - Administrative Assistant
Juan Valdez - Geochemistry
Rodolfo Van der Laat - Geodesy, deformation
Floribeth Vega - Data Analyst

Observatorio Vulcanológico y Sismológico de Costa Rica, Universidad Nacional (OVSICORI-UNA) operates a seismographic telemetered network which consists of 25 stations covering all the country and transmitting continuously to the hearquarter at Heredia. The main purpose of the network is to study the seismotectonic setting and to monitor seismic activity associated with volcanoes.

Hence, five of these stations are located close to active volcanoes : Rincon de la Vieja, Arenal, Poás, Irazú and Turrialba.

Additionally thirteen portable seismographs are ready for impending situations of local microseismicity or volcano activity.

The next table explains the monitoring routine techniques at each volcano, and it could be increased in the eventuality of abnormal activity.

RINCON DE LA VIEJA VOLCAN

Method Record periodicity
A permanent seismic station Continuous
One triangle of dry tilt Every year
Visual observation Twice a year

ARENAL VOLCANO

Method Record periodicity
A permanent seismic station Continuous
3 deformation radial distances 8 weeks
5 electronic tiltmeters 2 weeks
6 triangles of dry tilt 10 weeks
1 radial levelling line (1.6 km) 4 months
Fumarolic temperature 8 weeks (when possible)
6 H2O Geochemistry stations 2 weeks
2 Sakurajima traps (KOH) 4 weeks
Acid rain network (7 sta) 2 weeks
Radon emanometry (6 sta) 2 weeks
Visual observation 2 weeks
2 continuous GPS stations Continuous (daily positions)
5 broad band stations Continuous

 

PLATANAR VOLCANO

Method Record periodicity
2 triangles of dry tilt Once a year

 

POAS VOLCANO

Method Record periodicity
One permanent seismic station Continuous
Trilateration network (0.72 km2) 8 weeks
18 km radial levelling line 3 years
5 triangles of dry tilt 10 weeks
Fumarolic temperature 4 weeks
Fumarolic condensates 4 weeks
3 Sakurajima traps (KOH) 4 weeks
Acid rain network (7 sta) 2 weeks
Radon emanometry (9 sta) 2 weeks
Visual observation 2 weeks

 

IRAZU VOLCANO

Method Record periodicity
One permanent seismic station Continuous
Trilateration network (1 km2) 8 weeks
Levelling line and occasional gravimetry survey 3 years
6 triangles of dry tilt 10 weeks
Fumarolic temperature Yearly
Fumarolic condensates Yearly
Radon emanometry (5 sta) 2 weeks
Visual observation 2 weeks

 

TURRIALBA VOLCANO

Method Record periodicity
One permanent seismic station Continuous
6 triangles of dry tilt

10 weeks

Fumarolic temperature 8 weeks
Fumarolic condensates 8 weeks
1 Sakurajima trap (KOH) 4 weeks
Acid rain network (3 sta) 2 weeks
Radon emanometry (3 sta) 2 weeks
Visual observation 2 weeks

INSTRUMENTATION

Seismology

25 telemetered seismographic stations. Each equipment consists of a Ranger SS-1 vertical seismometer, 1 Hz preamplifier and oscillator controller, VHF or UHF radio link and solar panel. The signal is recorded at the Observatory on thermal paper. Digital recording system started in Dec 91.

1 station has one ow gain horizontal component (Wood Anderson Type).

13 Portable MEQ 800 seismic stations.

Deformation

Automatic level NaK2, Wild

Automatic level AL2, Pentax

4 tripod

Theodolite T2000, Wild (UCSC)

EDM DI 3000, Wild (UCSC)

2 GPS antennas, receivers (UCSC)

5 broad band seismometers (Streckeison) (UCSC)

Geochemistry

Thermometer, Thermocouples

Gas and water sampling devices and pipes

6 Sakurajima traps for sampling acid gases

23 double check radon stations

17 acid rain (field stations)

1 specific ton analizer

1 spectrophotometer

1 analytic balance

1 distillator

2 soil ovens

gas chromatograph

Fon chromatograph

AA instrument (6/93)

Petrography

3 rock saws (for thin sections)

3 polishing machines (thin sections)

3 petrographic microscopes

Information updated August 1996

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