2018-01-15 (IPMA)
The earthquake that occurred at 11:51 (UTC), with a magnitude ML = 4.9, was located in the NE region of Arraiolos, near Aldeia da Serra. The hypocenter (preliminary) has the coordinates 38,779 N, 7,960 W and the depth of 11.8 km.
Indicating a focal mechanism compatible with the determinations made for earthquakes that occurred previously in the same region, for example the earthquake that occurred on July 31, 1998 with magnitude 4.
This earthquake occurs in a known area of seismicity, usually referred to as the "seismic cluster" of Arraiolos, where morphological accidents and geological studies point to a dominant WNW-ESE orientation. The origin of these earthquakes is associated with a transition zone between a relatively quiet area to the north, and an area more seismically active area to the South, within an area called the "Ossa-Morena Zone".
IPMA has already sent a team of seismologists to carry out the macro-seismic survey in the region. This survey is important for the characterization of seismic risk in the region.
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