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Instituto de Investigação
em Vulcanologia e Avaliação de Riscos

Teses ► Mestrado


Referência Bibliográfica

FONTIELA, J. (2009) - Human losses and damage expected in future earthquakes in Faial Island - Azores; a contribution to risk mitigation. MSc thesis in Environmental and Spatial Planning, Azores University, 89p.​


On August 30th, 1926 Faial Island was struck by a strong earthquake, the local population had no memory of such catastrophe. This earthquake caused a large devastation in Horta city and surrounding villages; there are still stories that remember well that only one house was standing in Flamengos village. Based on descriptions published in newspapers and other press, the intensities felt in each settlement were reclassified using the 1998 Macroseismic European Scale. Therefore, the maximum intensity attributed to the Flamengo village is X, here the percentage of house destruction was 80%, with a damage level degree of 5. To the following villages it was attributed an intensity of IX , Praia do Almoxarife, Angústias, Conceição Matriz, Feteira e Pedro Miguel with a damage level degree ranging from 4 to 5.


QLARM is a tool that allows estimation of the number of victims in consequence of an earthquake; this tool was developed by WAPMERR in cooperation with the Swiss Seismological Services. To achieve an accurate estimation it is of most importance to calibrate QLARM using the following data: A) Population distribution by village; B) Household and population distribution by vulnerability classes, according to the EMS-98; C) Soil attenuation and amplification. The victim toll is calculated from: 1) Pertinent vulnerability Models, based on EMS -98 vulnerability classes; 2) Collapse rates of buildings are obtained trough past seismic occurrences; 3) The toll matrix based on EMS-98.


Given the tectonic and geological conditions of Faial the known attenuation relations do not fit to the existing conditions. Therefore, were tested several relations, and the model that best fitted was proposed by Munson & Thurber; It fitted better to PGA against magnitude. For soft soils the model uses a correction factor, which was replaced by 2 to incorporate QLARM.


The Geotechnical soil classification in Azores presents quit low shear wave velocity. Wald & Allen (2007) proposed methodology was tested in Faial; nevertheless the outcome fails to provide a trustworthy conclusion.


Based on Borcherdts work it’s suggested a reformulation of the prior classification by Wald & Allen (2007), but still needs further improvement.


QLARM validation using past earthquakes shows for patients a factor ranging between 2.6 to 4.6. The estimates of four scenarios shows the number of fatalities is about 254 to 1346 and patients range 80 to 463.