SEISMOLOGICAL OBSERVATORY AT QUINDIO UNIVERSITY (O.S.Q.): A FIRM LONG-TERM STEP TOWARD RESOLVING REGIONAL SEISMICITY
14 pages
Español

Découvre YouScribe en t'inscrivant gratuitement

Je m'inscris

SEISMOLOGICAL OBSERVATORY AT QUINDIO UNIVERSITY (O.S.Q.): A FIRM LONG-TERM STEP TOWARD RESOLVING REGIONAL SEISMICITY

-

Découvre YouScribe en t'inscrivant gratuitement

Je m'inscris
Obtenez un accès à la bibliothèque pour le consulter en ligne
En savoir plus
14 pages
Español
Obtenez un accès à la bibliothèque pour le consulter en ligne
En savoir plus

Description

ciales fue calculada usando sismos con distancias epicentrales entre 10Km y 300Km asi como las magnitudes de algunos sismos profundos con distancias hipocentrales entre 100 Km y 600 Km.
La evaluación del potencial sísmico en la región del Eje Cafetero empieza con el registro de la sismicidad reciente en Chocó y en la parte norte del departamento del Valle, y está basada en el análisis comparativo entre esta sismicidad y la registrada antes de la ocurrencia de los sismos mas importantes de los últimos 42 años. Finalmente, considerando las dos fuentes de subducción, un sismo cuya magnitud de momento sísmico entre 6.7 y 7.3 podría esperarse en la próxima década, con una probabilidad de 87% .

Sujets

Informations

Publié par
Publié le 01 janvier 2005
Nombre de lectures 24
Langue Español
Poids de l'ouvrage 1 Mo

Extrait

EARTH SCIENCES
RESEARCH JOURNAL
Earth Sci. Res. J. Vol. 9, No. 2 (Dec. 2005): 85-98
SEISMOLOGICAL OBSERVATORY AT QUINDIO UNIVERSITY
(O.S.Q.): A FIRM LONG-TERM STEP TOWARD RESOLVING
REGIONAL SEISMICITY
1,2 1,2Monsalve Jaramillo Hugo , Correa Montaño Isabel Cristina ,
1and Valencia Mina William
1 CEIFI, Quimbaya Research Group - Quindío University
2 Seismological Observatory at Quindío University - OSQ. E-mail: hugom@uniquindio.edu.co
RESUMEN
El Eje Cafetero (zona central de Colombia, cultivada con café), y en particular, el departamento del Quindío
es constantemente golpeada por sismos de diferentes magnitudes. Los sismos son el resultado de la compleja
tectónica regional debido a la interacción entre las placa Nazca, Caribe y Sur América. La convergencia
de estas placas es responsable de la formación de los Andes. Por estas razones, el OSQ (Observatorio
Sismológico del Quindío) e INGEOMINAS, como las entidades estatales encargadas de monitorear la
actividad sísmica, han de contribuir, a si como los centros regionales de investigación, al desarrollo de los
estudios sismológicos y el análisis de la actividad tectónica local, para así obtener nuevos conocimientos a
cerca de los desastres naturales que amenazan a las comunidades en la región y entender mejor la estructura
interna de la corteza en la región del Eje Cafetero.
La combinación de diferentes modelos de velocidad para la región del Eje Cafetero ha permitido la definición
de elementos clave para tener una mejor percepción de la estructura de la corteza. En consecuencia, la
determinación de un modelo de velocidades mejorado para la región cafetera ha ayudado a localizar mejor
los sismos y a determinar con mayor precisión los espesores de la corteza y la estructura del manto superior
entre los terrenos adyacentes que fueron generados en diferentes períodos geológicos.
La magnitud ML fue determinada para los campos cercanos e intermedios y usando el modelo presentado
en este articulo, el problema del rango dinámico de saturación de los sismógrafos durante sismos relevantes
en campo cercano es solucionado. La magnitud local de algunos sismos superficiales fue calculada usando
sismos con distancias epicentrales entre 10Km y 300Km asi como las magnitudes de algunos sismos
profundos con distancias hipocentrales entre 100 Km y 600 Km.
La evaluación del potencial sísmico en la región del Eje Cafetero empieza con el registro de la sismicidad
reciente en Chocó y en la parte norte del departamento del Valle, y está basada en el análisis comparativo
entre esta sismicidad y la registrada antes de la ocurrencia de los sismos mas importantes de los últimos
42 años. Finalmente, considerando las dos fuentes de subducción, un sismo cuya magnitud de momento
sísmico entre 6.7 y 7.3 podría esperarse en la próxima década, con una probabilidad de 87%.
Palabras clave: Quindío, sismicidad, instrumentación.
(Manuscript received May 2005,
Paper accepted October 2005)
85Hugo Monsalve Jaramillo, Isabel Cristina Correa Montaño and William Valencia Mina
ABSTRACT
The Coffee Belt (the central coffee-growing zone in Colombia), and more particularly, the state of Quindio
is constantly hit by earthquakes of different magnitudes. Earthquakes result from the complex regional
tectonics, brought about by interaction between the Nazca, Caribbean, and South American plates. The
convergence of these plates is responsible for the formation of the Andes. For these reasons, the OSQ
(Sesimological Observatory of Quindio, from its acronym in Spanish) and INGEOMINAS, as government
offices in charge of monitoring earthquake activity, have to contribute, along with research centers of the
region, to the development of seismological studies and analysis of local tectonic activity in order to obtain
new knowledge regarding natural disasters which are threat to the communities in region and be able to
better understand the internal crustal structure in the Coffee Belt region.
The combination of different velocity models for the Coffee Belt region has allowed the definition of key
elements to have better insight about the structure of the crust. Consequently, determining an improved new
velocity model for the Colombian coffee-growing region has helped to a better location of earthquakes and
to a more accurate determination of differences in crustal thickness and the structure of the upper mantle
between adjacent terrains that were built during different geological periods.
The ML magnitude was determined for the near and intermediate fields, and, using the model presented in
this article, the problem of dynamic range saturation of seismographs during relevant earthquakes in near
field is overcome. The local magnitude of some shallow earthquakes was calculated using shocks with
epicentral distances ranging between 10km and 300km as well as the magnitudes of some deep earthquakes
with hypocentral distances ranging between 100km and 600km.
Seismic potential assessment in the Coffee Belt region begins with recent seismicity recorded in Chocó and
the northern part of Valle (a state in Colombia) and is based on comparative analysis between this seismicity
and the one recorded before the occurrence of the most important earthquakes in the last 42 years. Finally,
taking into consideration the two subduction sources, an earthquake with seismic moment magnitude ranging
between 6.7 and 7.3 could be expected within the next decade, having a probability of 87%.
Key words: Quindío, sismicity, instrumentation.
© 2005 ERSJ - Unibiblos
INTRODUCTION which belongs to Manizales Volcanological and
Seismological Observatory OVSM).
As a result of the emergency caused by the January Since May 1999, when the observatory began
25, 1999, Mw 6.2 Quindio earthquake, Quindio operations, and up to now, the O.S.Q. has been in
University and INGEOMINAS worked jointly charge of carrying out seismic monitoring activities
in the installation and operation of a temporary in Quindio associated to active faults in the area,
seismograph network, assigning this responsibility to however, other local and relevant worldwide seismic
the Studies and Research Center of the Engineering activity is also detected.
Faculty (CEIFI) which became, since February 1999, In terms of knowing regional seismicity, the
the seismological observatory of Quindio University, information collected by the local network has
using telemetry instruments, seismographs, and been of vital importance in understanding the local
accelerographs borrowed from INGEOMINAS in geodynamic processes related to urban planning
order to monitor the aftershocks. Currently, there are and risk management activities in the region,
eight accelerographs in operation and six telemetered identifying seismic sources, activity that CEIFI has
seismograph stations (Table 1), five of which are been conducting. In addition, the information that is
located in Armenia and one in Manizales (RODEO, analyzed and provided by CEIFI is, and has been, of
86Seismological Observatory at Quindío University (O.S.Q.): A firm Long-Term Step Toward Resolving Regional Seismicity
great support to different government officials involved in civil protection and disaster prevention activities
in order to carry out programs of information diffusion and disaster management.
TABLE 1. OSQ STATION NETWORK.
TYPE STATIÓN DEPARTAMENT CITY/TOWN LATITUDE LONGITUDE
ACCELEROGRAPHIC (Quindío
University) UNIQUINDÍO Quindío Armenia 4.506° -75.624°
CALARCÁ Calarcá 4.549° -75.618°
POSCOSECHA Quindío Armenia 4.506° -75.624°ACCELEROGRAPHIC
GÉNOVA Génova 4.219° -75.775°(ACCELEROGRAPHIC
(Agreement with Colombian DAGUA Valle Dagua 3.662° -76.708°
National Accelerographs CALIMA Valle Calima-Darien 3.884° -76.580°
Network– RNAC)) TRUJILLO Valle Trujillo 4.228° -76.334°
TOCHE Valle Toche 3.650° -76.090°
GUAYAQUIL Quindío Planadas 4.460° -75.625°
LA MINA * Pijao 4.377° -75.727°
RODEO Tolima Machin Volcano 4.490° -75.392°
SEISMOLOGICAL CAICEDONIA Valle Caicedonia 4.320° -75.814°
RIBER * Valle Ribera Alta 4.519° -75.889°
MODIN * Valle Cartago 4.670° -75.875°
(* not operating permanently)
A seismograph network is a useful tool to know and broadcasting activities are being carried out 365
the inner structure of the Earth, earthquake days a year.
waves propagation patterns, earthquake-source In order to generate new knowledge about the natural
mechanisms, as well as urban seismic microzoning hazards to which the region is constantly exposed,
and hazard assessment of a specific region. For this research projects are developed. These projects
purpose, it is necessary to have qualified staff that is allow knowing, assessing, and improving social
trained in processing and analyzing data, capable of development conditions and subsoil conditions to
improving their knowledge of seismic phenomena provide early advise on disaster prevention and the
and generating new hypothesis regarding seismic determination

  • Univers Univers
  • Ebooks Ebooks
  • Livres audio Livres audio
  • Presse Presse
  • Podcasts Podcasts
  • BD BD
  • Documents Documents