No. Registros Solicitud 1 5614 colombia

CP - COUNTRY OF PUBLICATION: United-States

PY - PUBLICATION YEAR: 1995

CN - CONFERENCE INFORMATION: 1995 annual meeting. Maryville, MO, United States. April 21-22, 1995.

LA - LANGUAGE: English

DE - DESCRIPTORS: Albian-; Colombia-; correlation-; Cretaceous-; Dinoflagellata-; floods-; Lower-Cretaceous; marine-environment; Mesozoic-; microfossils-; organic-compounds; Ortega-Coyaima-Colombia; Oxal-Formation; paleoenvironment-; palynomorphs-; petroleum-; sequence-stratigraphy; source-rocks; South-America; Tolima-Colombia; Villeta-Group

CC - CATEGORY CODES: 12-Stratigraphy

DT - DOCUMENT TYPE: Abstract; Serial; Conference-Document

BL - BIB LEVEL: Analytic

RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute.

IS - ISSN: 0544-540X

CO - CODEN: MISTBW

AN - ACCESSION NUMBER: 2002-024416

UD - UPDATE CODE: 200210

Registro 601 de 5614 - GeoRef : 2002-2004/12

TI - TITLE: Possible timing of large earthquakes by 18.6-year lunar cycles, their multiples, and fractions.

AU - AUTHORS: Gusev-A-A; Petukhin-A-G

AF - AUTHOR AFFILIATION: Russian Academy of Sciences, Institute of Volcanic Geology and Geochemistry, Petropavlovsk-Kamchatskiy, Russian Federation

SO - SOURCE: Volcanology and Seismology. 19; 3, Pages 333-351. 1998.

PB - PUBLISHER: Gordon and Breach Science Publishers. New York, NY, United States. 1998.

CP - COUNTRY OF PUBLICATION: United-States

PY - PUBLICATION YEAR: 1998

LA - LANGUAGE: English

DE - DESCRIPTORS: Asia-; Cenozoic-; Colombia-; Commonwealth-of-Independent-States; correlation-; cyclic-processes; data-processing; earthquake-prediction; earthquakes-; Ecuador-; global-; great-earthquakes; Holocene-; Kamchatka-Peninsula; Kamchatka-Russian-Federation; Kuiper'-s-test; lunar-cycle; mathematical-methods; Moon-; periodicity-; Peru-; precession-; Quaternary-; Russian-Federation; Russian-Pacific-region; seismology-; South-America; spectral-analysis; subduction-zones; upper-Holocene

CC - CATEGORY CODES: 19-Seismology

DT - DOCUMENT TYPE: Serial

BL - BIB LEVEL: Analytic

NN - ANNOTATION: Includes appendix.

IL - ILLUSTRATION: Refs: 25; illus. incl. 4 tables, charts.

RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute.

IS - ISSN: 0742-0463

AN - ACCESSION NUMBER: 2002-024160

UD - UPDATE CODE: 200210

Registro 602 de 5614 - GeoRef : 2002-2004/12

TI - TITLE: Zonificacion sismica en paises Bolivarianos

Translated Title: Seismic zoning in Venezuela, Colombia, Ecuador and Peru.

AU - AUTHORS: Aguiar-Falconi-Roberto; Haro-Baez-Ana-G

AF - AUTHOR AFFILIATION: Escuela Superior del Ejercito, Centro de Investigaciones Cientificas, Quito, Ecuador

SO - SOURCE: Boletin Informativo- IMME. 38; 3, Pages 27-41. 2000.

PB - PUBLISHER: Universidad Central de Venezuela, Instituto de Materiales y Modelos Estructurales, Facultad de Ingenieria. Caracas, Venezuela. 2000.

CP - COUNTRY OF PUBLICATION: Venezuela

PY - PUBLICATION YEAR: 2000

LA - LANGUAGE: Spanish

LS - LANGUAGE OF SUMMARY: English

AB - ABSTRACT: The seismic zonification of the current regulations, updated to the year 2000, in Venezuela, Colombia, Ecuador and Peru are analyzed. Previously, the zonifications obtained in the same countries, using the regulations of the early eighties, when seismic danger started being calculated in probabilistic terms, were compared to current regulations. On the other hand, an isoacceletarions map for Latin America, done by CERESIS in 1996, is presented. The map shows the degree of correlation existent with the seismic zonifications of Bolivarian countries. The zonification maps analyzed present the maximum soil acceleration in rock and hard soil, for a useful structure life of 50 years, and an exceedence probability of 10%. This is the base to obtain elastic design spectra. Thereinafter, the need to have a new presentation format of the seismic zonification is remarked, in such a way to allow finding the maximum soil acceleration for different return periods of the structure. Finally, the importance factor of different codes is analyzed, and the exceedence probability is determined, for maximum soil accelerations of 40% of gravity, in buildings for different uses.

DE - DESCRIPTORS: acceleration-; Andes-; Colombia-; Ecuador-; gravity-anomalies; mapping-; measurement-; Peru-; seismic-risk; seismic-zoning; seismicity-; soil-mechanics; South-America; Venezuela-

CC - CATEGORY CODES: 19-Seismology

DT - DOCUMENT TYPE: Serial

BL - BIB LEVEL: Analytic

IL - ILLUSTRATION: Refs: 34; illus. incl. 3 tables, sketch maps.

RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute.

IS - ISSN: 0376-723X

CO - CODEN: #00385

AN - ACCESSION NUMBER: 2002-023216

UD - UPDATE CODE: 200209

Registro 603 de 5614 - GeoRef : 2002-2004/12

TI - TITLE: Seismic analysis, design and evaluation of hospitals; vulnerability studies by energy methods.

AU - AUTHORS: Cardona-Omar-D; Hurtado-Jorge-E

AF - AUTHOR AFFILIATION: Universidad de los Andes, Bogata, Colombia

BK - BOOK TITLE: In: Natural disaster reduction; proceedings of the conference sponsored by the American Society of Civil Engineers.

BA - BOOK AUTHORS: Housner-George-W (editor); Chung-Riley-M (editor)

SO - SOURCE: Pages 319-320. 1996.

PB - PUBLISHER: American Society of Civil Engineers. New York, NY, United States. 1996.

CP - COUNTRY OF PUBLICATION: United-States

PY - PUBLICATION YEAR: 1996

CN - CONFERENCE INFORMATION: Natural disaster reduction. Washington, DC, United States. Dec. 3-5, 1996.

LA - LANGUAGE: English

DE - DESCRIPTORS: aseismic-design; buildings-; Colombia-; earthquakes-; energy-; geologic-hazards; hospitals-; risk-assessment; seismic-risk; South-America; stability-

CC - CATEGORY CODES: 30-Engineering-geology

DT - DOCUMENT TYPE: Abstract; Book; Conference-Document

BL - BIB LEVEL: Analytic

RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute.

IB - ISBN: 0-7844-0153-5

AN - ACCESSION NUMBER: 2002-022221

UD - UPDATE CODE: 200209

Registro 604 de 5614 - GeoRef : 2002-2004/12

TI - TITLE: Analysis of individual fluid inclusions using synchrotron X-ray fluorescence microprobe; progress toward calibration for trace elements.

AU - AUTHORS: Menez-Benedicte; Philippot-Pascal; Bonnin-Mosbah-Michelle; Simionovici-Alexandre; Gibert-Francois

AF - AUTHOR AFFILIATION: Commissariat a l'Energie Atomique-Centre National de la Recherche Scientifique, Laboratoire Pierre Suee, Gif Sur Yvette, France

SO - SOURCE: Geochimica et Cosmochimica Acta. 66; 4, Pages 561-576. 2002.

PB - PUBLISHER: Pergamon. Oxford, International. 2002.

CP - COUNTRY OF PUBLICATION: International

PY - PUBLICATION YEAR: 2002

LA - LANGUAGE: English

AB - ABSTRACT: A critical problem for conducting quantitative analysis of individual fluid inclusions using Synchrotron X-Ray Fluorescence (SXRF) technique relates to the standardization and the calibration of the X-ray spectra. In this study, different approaches have been tested for calibration purposes: (a) the use of chlorine when Cl content can be estimated either from melting point depressions of undersaturated fluid inclusions or from saturation limits for halite-bearing fluid inclusions, (b) the use of calcium from synthetic fluid inclusions of known CaCl (sub 2) content as an external standard. SXRF analysis was performed on individual fluid inclusions from the Chivor and Guali emerald deposits, Columbia. These well-known samples contain a single fluid inclusion population for which detailed crush-leach analyses are available, thus providing a relevant compositional reference frame. Concentration estimates were also compared to Particle Induced X-ray Emission (PIXE) analysis carried out independently on the same fluid inclusions. Results of the calibration tests indicate that major (Cl, K, Ca, Fe, Mn) and trace element (Cu, Zn, As, Br, Rb, Sr, Ba, Pb) concentration estimates can be performed without precise knowledge of the analytical volume and the inclusion's 3D geometry. Although the standard deviation of the SXRF results can be relatively high depending on the calibration mode used, mean concentration estimates for most elements are in good agreement with PIXE and crush-leach analysis. Elemental distributions within single fluid inclusions were also established. Associated correlation diagrams argue for the homogeneous distribution of most elements in the fluid inclusion. In contrast, Br shows a bimodal distribution interpreted to reflect a significant enrichment of the vapor portion of the inclusion fluid.

DE - DESCRIPTORS: applications-; calibration-; chemical-analysis; Colombia-; emerald-; emission-spectroscopy; experimental-studies; fluid-inclusions; inclusions-; laboratory-studies; natural-materials; particle-induced-X-ray-emission; quantitative-analysis; ring-silicates; silicates-; South-America; spectroscopy-; synchrotrons-; techniques-; trace-element-analyses; X-ray-analysis; X-ray-fluorescence; X-ray-spectroscopy

CC - CATEGORY CODES: 02A-General-geochemistry

DT - DOCUMENT TYPE: Serial

BL - BIB LEVEL: Analytic

IL - ILLUSTRATION: Refs: 40; illus. incl. 7 tables.

RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands

IS - ISSN: 0016-7037

CO - CODEN: GCACAK

AN - ACCESSION NUMBER: 2002-022020

UD - UPDATE CODE: 200208

Registro 605 de 5614 - GeoRef : 2002-2004/12

TI - TITLE: On the applicability of neural networks for soil dynamic amplification analysis.

AU - AUTHORS: Hurtado-J-E; Londono-J-M; Meza-M-A

AF - AUTHOR AFFILIATION: Universidad Nacional de Colombia, Manizales, Colombia

SO - SOURCE: Soil Dynamics and Earthquake Engineering (1984). 21; 7, Pages 579-591. 2001.

PB - PUBLISHER: CML Publications. Southampton, International. 2001.

CP - COUNTRY OF PUBLICATION: International

PY - PUBLICATION YEAR: 2001

LA - LANGUAGE: English

AB - ABSTRACT: Artificial Neural Networks (ANN) have gained a solid status as a tool for modeling complex phenomena in different areas of research and engineering practice. In this paper, their applicability to estimate the mapping of seismic acceleration from bedrock to free surface in a complex soil profile is explored. Such a use is intended to serve as a hypothesis-free alternative to the dynamic amplification analysis, which is currently based on geophysical and soil dynamics procedures. Were the neural networks to be useful to such a mapping, they could in principle be employed for several purposes, such as soil identification using instrumental data, design of early warning systems and estimation of probabilistic spectra via Monte Carlo simulation, in which the ANN act as an efficient solver surrogate. The conditions under which these ambitious purposes can be reached are discussed. Two classes of multi-layer perceptrons were tested, which are characterized by time-independent and time-dependent connections. It is shown that the first class of networks is useful for response spectrum mapping, while the second performs very well in the assessment of free-surface time series. It arises as the main conclusion that the most promising perspective of application of ANN in this respect is for the estimation of probabilistic free-surface spectra, which is an important goal for the modern trend of reliability-based aseismic design. The limitations to the other said applications are also highlighted.

DE - DESCRIPTORS: algorithms-; artificial-neural-networks; Monte-Carlo-analysis; neural-networks; probability-; seismic-response; seismicity-; soil-mechanics; soil-profiles; statistical-analysis; wave-amplification

CC - CATEGORY CODES: 30-Engineering-geology

DT - DOCUMENT TYPE: Serial

BL - BIB LEVEL: Analytic

IL - ILLUSTRATION: Refs: 15; illus.

RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands

IS - ISSN: 0267-7261

CO - CODEN: #03372

AN - ACCESSION NUMBER: 2002-020121

UD - UPDATE CODE: 200208

Registro 606 de 5614 - GeoRef : 2002-2004/12

TI - TITLE: CO (sub 2) - and temperature-controlled altitudinal shifts of C (sub 4) - and C (sub 3) -dominated grasslands allow reconstruction of palaeoatmospheric pCO (sub 2) .

AU - AUTHORS: Boom-Arnoud; Marchant-Robert; Hooghiemstra-Henry; Sinninghe-Damste-J-S

AF - AUTHOR AFFILIATION: University of Amsterdam, Institute for Biodiversity and Ecosystem Dynamics, Amsterdam, Netherlands

BK - BOOK TITLE: In: Reconstruction and modelling of grass-dominated ecosystems.

BA - BOOK AUTHORS: Beuning-Kristina-R-M (editor); Wooller-Matthew-J (editor)

SO - SOURCE: Palaeogeography, Palaeoclimatology, Palaeoecology. 177; 1-2, Pages 151-168. 2002.

PB - PUBLISHER: Elsevier. Amsterdam, Netherlands. 2002.

CP - COUNTRY OF PUBLICATION: Netherlands

PY - PUBLICATION YEAR: 2002

CN - CONFERENCE INFORMATION: First Paleo-Grassland Research workshop (PGR 2000). Westbrook, CT, United States. 2000.

LA - LANGUAGE: English

AB - ABSTRACT: During the Pleistocene the vegetation changes in the high Colombian Andes included changes from C (sub 3) to C (sub 4) plants. This is inferred from delta (super 13) C values of the C (sub 31) n-alkane from the Funza-2 sedimentary record taken from the high plain of Bogota at 2550 m elevation. The environmental factors thought to be responsible for these changes were investigated using a single point simulation of the BIOME3 vegetation model, including changes in precipitation, temperature and atmospheric CO (sub 2) concentrations. The model shows that changes are for a major part caused by these latter two factors. The isotopic signature of the n-alkanes of several extant C (sub 3) and C (sub 4) grasses from the area were determined to calibrate the interpretation of the isotopic record. From the geochemical record, we estimated the altitudinal distribution of C (sub 3) and C (sub 4) plants, using present grass distribution patterns based on floristic data as a template. This information, in combination with palaeotemperature estimates, enabled the reconstruction of atmospheric CO (sub 2) concentrations. The reconstructed CO (sub 2) concentrations follow the trends of the Vostok Antarctic ice core through three glacial and two interglacial stages. The lowest calculated CO (sub 2) concentration is ca. 210 ppmV for the glacial maxima and within the range of lowest values from Vostok, our highest value (310 ppmV) is for interglacial MIS 7. This represents a new method to reconstruct palaeoatmospheric pCO (sub 2) . It is less accurate than measurements from ice cores, but has potential to be used for sediments that are much older than the ice cores.

DE - DESCRIPTORS: aliphatic-hydrocarbons; alkanes-; altitude-; Andes-; Angiospermae-; BIOME3-; biomes-; Bogota-Colombia; carbon-dioxide; Cenozoic-; Colombia-; controls-; cores-; data-processing; digital-simulation; Funza-II; glacial-environment; Gramineae-; grasses-; grasslands-; hydrocarbons-; interglacial-environment; Monocotyledoneae-; n-alkanes; numerical-models; organic-compounds; paleoatmosphere-; paleoclimatology-; paleoecology-; paleohydrology-; paleotemperature-; plains-; Plantae-; Pleistocene-; Quaternary-; reconstruction-; sediments-; South-America; Spermatophyta-; temperature-; terrestrial-environment; vegetation-

CC - CATEGORY CODES: 24-Quaternary-geology

DT - DOCUMENT TYPE: Serial; Conference-Document

BL - BIB LEVEL: Analytic

MC - MAP COORDINATES: LAT: N045000; N045000; LONG: W0741200; W0741200.

NN - ANNOTATION: Neth. Inst. Sea Res. (NIOZ), Contrib. No. 3536.

IL - ILLUSTRATION: Refs: 68; illus. incl. sketch map.

RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands

IS - ISSN: 0031-0182

CO - CODEN: PPPYAB

AN - ACCESSION NUMBER: 2002-019287

UD - UPDATE CODE: 200207

Registro 607 de 5614 - GeoRef : 2002-2004/12

TI - TITLE: Pollen-based biome reconstructions for the past 450 000 yr from the Funza-2 Core, Colombia; comparisons with model-based vegetation reconstructions.

AU - AUTHORS: Marchant-Robert; Boom-Arnoud; Hooghiemstra-Henry

AF - AUTHOR AFFILIATION: University of Amsterdam, Hugo de Vries Laboratory, Amsterdam, Netherlands

BK - BOOK TITLE: In: Reconstruction and modelling of grass-dominated ecosystems.

BA - BOOK AUTHORS: Beuning-Kristina-R-M (editor); Wooller-Matthew-J (editor)

SO - SOURCE: Palaeogeography, Palaeoclimatology, Palaeoecology. 177; 1-2, Pages 29-45. 2002.

PB - PUBLISHER: Elsevier. Amsterdam, Netherlands. 2002.

CP - COUNTRY OF PUBLICATION: Netherlands

PY - PUBLICATION YEAR: 2002

CN - CONFERENCE INFORMATION: First Paleo-Grassland Research workshop (PGR 2000). Westbrook, CT, United States. 2000.

LA - LANGUAGE: English

AB - ABSTRACT: The 586-m Funza-2 sequence from the high plain of Bogota, Colombia has provided one of the longest pollen-based vegetation reconstructions in the world. Affinity scores to seven biomes are compared to the record of CO (sub 2) fluctuation from the Vostok ice core for the period spanning from approximately 25000 to 450000 yr before present (BP). Results are compared to output from the BIOME-3 vegetation model run under different environmental scenarios at regional and local scales. The model is run with temperature and precipitation reductions, relative to the present values, of up to -10 degrees C and -700 mm yr (super -1) respectively. For this particular investigation we are interested in the role of CO (sub 2) as a forcer of vegetation change; we run the model with concentrations of atmospheric CO (sub 2) ([CO (sub 2) ] (sub atm.) ) within the range of 170 to 340 ppmV. During glacial periods, the cool grass/shrubland biome is highly dominant, less so during interglacial periods when the cool evergreen and cool mixed forest biomes become co-dominant. In addition to this climate-driven altitudinal oscillation of the vegetation, there is also a signal that indicates longer term evolution of the vegetation. The cool grass/shrubland and cool evergreen and cool mixed forest biomes become co-dominant for the first time over the 450000-yr record at approximately 170000 yr BP, become completely anti-phase (during a period of extreme low [CO (sub 2) ] (sub atm.) ) and then become co-dominant from approximately 120000 yr BP until the core top, just prior to the last glacial maximum. The model results for the Funza area indicate that changes in [CO (sub 2) ] (sub atm.) , temperature and precipitation are inter-linked by the vegetation response. A shift of 5.5 degrees C is required to lower the cool grass/shrubland biome to altitudes about the Funza catchment where the Andean forest biome dominant. At low [CO (sub 2) ] (sub atm.) concentrations, particularly below 180 ppmV, the composition of the high latitudinal tropical vegetation about the Funza catchment changed. It is suggested that this low [CO (sub 2) ] (sub atm.) , combined with a period when the climate was characterised by extreme cooling and drying, caused a readjustment of the tropical high altitudinal vegetation zonation and the formation of plant communities that are presently recorded.

DE - DESCRIPTORS: Andes-; atmosphere-; BIOME-3; biomes-; Bogota-Colombia; carbon-dioxide; Cenozoic-; climate-change; Colombia-; cores-; data-processing; digital-simulation; Funza-II; glacial-environment; grasslands-; microfossils-; miospores-; numerical-models; paleoecology-; palynomorphs-; pollen-; postglacial-environment; Quaternary-; reconstruction-; South-America; terrestrial-environment; tropical-environment; upper-Quaternary; vegetation-

CC - CATEGORY CODES: 24-Quaternary-geology

DT - DOCUMENT TYPE: Serial; Conference-Document

BL - BIB LEVEL: Analytic

MC - MAP COORDINATES: LAT: N045000; N045000; LONG: W0741200; W0741200.

IL - ILLUSTRATION: Refs: 73; illus. incl. 2 tables, sketch map.

RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands

IS - ISSN: 0031-0182

CO - CODEN: PPPYAB

AN - ACCESSION NUMBER: 2002-019280

UD - UPDATE CODE: 200207

Registro 608 de 5614 - GeoRef : 2002-2004/12

TI - TITLE: Magma reservoir processes inferred from magma mixing in tephra deposits.

AU - AUTHORS: Sigurdsson-Haraldur

AF - AUTHOR AFFILIATION: University of Rhode Island, Graduate School of Oceanography, Narragansett, RI, United States

BK - BOOK TITLE: In: Geological Society of America, Northeastern Section, 34rd annual meeting.

BA - BOOK AUTHORS: Anonymous

SO - SOURCE: Abstracts with Programs - Geological Society of America. 31; 2, Pages 68. 1999.

PB - PUBLISHER: Geological Society of America (GSA). Boulder, CO, United States. 1999.

CP - COUNTRY OF PUBLICATION: United-States

PY - PUBLICATION YEAR: 1999

CN - CONFERENCE INFORMATION: Geological Society of America, Northeastern Section, 34rd annual meeting. Providence, RI, United States. March 22-24, 1999.

LA - LANGUAGE: English

DE - DESCRIPTORS: Campania-Italy; Colombia-; Europe-; explosive-eruptions; igneous-rocks; inclusions-; Italy-; magma-chambers; magmas-; mixing-; Nevado-del-Ruiz; phenocrysts-; pumice-; pyroclastics-; South-America; Southern-Europe; Vesuvius-; volcanic-rocks; volcanoes-

CC - CATEGORY CODES: 05A-Igneous-and-metamorphic-petrology

DT - DOCUMENT TYPE: Abstract; Serial; Conference-Document

BL - BIB LEVEL: Analytic

MC - MAP COORDINATES: LAT: N404900; N404900; LONG: E0142600; E0142600.

RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States

IS - ISSN: 0016-7592

CO - CODEN: GAAPBC

AN - ACCESSION NUMBER: 2002-018512

UD - UPDATE CODE: 200207

Registro 609 de 5614 - GeoRef : 2002-2004/12

TI - TITLE: Comparison between different techniques for evaluation of predominant periods using strong ground motion records and microtremors in Pereira, Colombia.

AU - AUTHORS: Ojeda-Anibal; Escallon-J

AF - AUTHOR AFFILIATION: University of Bergen, Institute of Solid Earth Physics, Bergen, Norway

BK - BOOK TITLE: In: SDEE'99; the 9th international conference on Soil dynamics and earthquake engineering.

BA - BOOK AUTHORS: Atakan-K (editor)

SO - SOURCE: Soil Dynamics and Earthquake Engineering (1984). 20; 1-4, Pages 137-143. 2000.

PB - PUBLISHER: CML Publications. Southampton, International. 2000.

CP - COUNTRY OF PUBLICATION: International

PY - PUBLICATION YEAR: 2000

CN - CONFERENCE INFORMATION: SDEE'99; the 9th international conference on Soil dynamics and earthquake engineering. Bergen, Norway. July 9-12, 1999.

LA - LANGUAGE: English

AB - ABSTRACT: This paper presents a comparison between different techniques for evaluation of predominant periods in soft soil, for the urban area of Pereira city, western Colombia. In this study we used microtremor and strong ground motion records obtained by a local array of seven accelerographs stations deployed in the city. Response spectra and spectral ratios have been calculated and compared with strong seismic events recorded in solid rock and soft soil stations. These observations allowed the determination of dominant response spectra for several sectors in the urban area. For the microtremor measurements and earthquake data, dominant periods were determined using interpretation of Fourier amplitude spectra and Nakamura's technique. A comparison between dominant periods obtained from strong ground motion records and those obtained from microtremor measurements show similarities, which is in the range 0.2-0.5s. A preliminary version of a site response map for Pereira city was obtained from this analysis.