Andalusian scientists create Spain's largest seismic and GPS station network

Topo-Iberia), whose aim is to create Spain’s largest seismic and GPS station network. This initiative, which will involve over 103 research doctors from ten different Spanish teams, will allow to get better models of the lithosphere structure from natural seismicity, by creating an unprecedented large reliable database and quantifying the current seismic movements in the Iberian Peninsula.

In order to carry out this research project, the Spanish Ministry of Education and Science subsidized it with a 4.5 million euros-grant last autumn. The Andalusian groups involved in the project belong to the universities of Jaén, Cádiz and Pablo Olavide, and will be coordinated by the head of the Geodynamics Department of the University of Granada, Dr. Francisco González Lodeiro.

This project implies the display of a temporary broad band seismic network without precedent in Spain; it will consist of a minimum of 80 seismic stations about 50-60 km away from each other, which will give simultaneous homogeneous coverage to different regions. In addition to this, Topo-Iberia will create Spain’s largest GPS network ever.

The real novelty of this project is that it provides an integrated analysis of the influence of superficial and deep processes, like other international top projects as TopoEurope/EuroArray in Europe and the Earthscope program in the USA.

Thanks to this initiative, researchers will be able to know the processes and mechanisms that cause seismic movements (both superficial and deep ones) which currently occur in the Iberian Peninsula and their relationship with the rest of Spain and Africa. In addition to this, Topo-Iberia tackles the structure and dynamics of the lithosphere in Spain.

Seismic hazard map

In addition to this, a team of researchers of the University of Granada, in collaboration with Italian scientists, are analysing the epicentres of earthquakes that occurred in the past in order to make seismic hazard maps to avoid future damage. The exact point where disasters were caused, such as the earthquakes of Alhama in 1884 and Malaga in 1680, were not known until now because the seismic stations that registered the earthquakes and send a signal to the observatories to establish the location did not start to fully work until the beginning of the 20th century.

This new aspect will not only be useful to get to learn about the seismic past of southern Spain, but also to take prevention measures so as to make viable construction formulas, buildings in compacted land and the exact location of the areas that run a high hazard in the future so that great damage can be avoided.

The method used by these Granada-based geo-physicians to find the epicentre of the seismic movements that occurred some centuries ago consisted of distributing per zones –thanks to a mathematical technique designed by themselves- the areas where the damage occurred so as to find the epicentre from there.

The data taken from this work are very useful indeed to make seismic hazard maps, as not only the areas affected by the earthquake will be considered now but also the actual point where the earthquake started, and therefore, the most likely to be damaged in the future.

Research abroad

Finally, the University of Jaén is leading a project awarded by the Spanish International Cooperation Agency (AECI), which belongs to the Spanish Foreign Affairs Ministry. Its aim is to assess the seismic hazards in northern Morocco. The universities of Granada and Mohamed V of Morocco will also take part in this research work, which is a first phase of the calculation of seismic hazards in northern Morocco. In this phase, all the necessary information to assess the probability of earthquakes to happen will be gathered and analysed, as well as the possible effects in the region.

In the last few years, northern Morocco, the country’s most seismic dangerous area, has become the object of studies due to the many high-intensity earthquakes that have taken place there which caused important material and human losses, the last one being in Alhucemas in February 2004.

Dr. José Antonio Peláez, of the University of Jaen, the project leader, said- ‘When you assess the seismic danger of an area, you try to find out how relevant seismic activity is in that area so that you know what to expect; this way you can try to improve the construction rules in areas that are more likely to suffer an earthquake’. Peláez underlined that this is the first study of these characteristics carried out in Morocco.

Previous studies were less ambitious and thorough, were made by local researchers and did not offer a wide panorama of what seismic activity in Morocco is like. The team work has already carried out similar assessments in Spain, Portugal and Algeria, the results being published in international scientific journals.

In this first phase of the AECI project, a Spanish politics international cooperation management body for development, there are two stages- obtaining a thorough reliable seismic catalogue, and the second one, a seism tectonic information gathering stage. During the first one, any information that Moroccan and other international researchers have on Moroccan earthquakes will be compiled, and then it will be filtered and validated later on.

The second stage will consists of gathering and analysing geo tectonic studies carried out so far, in northern Morocco, so see to what extent they show some light on the seismic danger in that area. All this processed information will allow the group of scientists, during a second stage, to determine what is the probability for an earthquake of certain characteristics to occur and its effects in this area.

The leader of the project stressed the importance of reviewing, in this first phase, the information available on this earthquakes, as there are some that have been classified with a certain intensity and with the pass of time their effects can be analysed better with more documental information. José Antonio Peláez added: ‘This is the information we have to review and validate’.