  Starting in April 2004, unusual seismic activity was observed in the interior
of the island of Tenerife (Canary Islands, Spain) with much evidence pointing
to a reawakening of volcanic activity. This seismicity is now analyzed with
techniques unprecedented in previous studies of this crisis. The 200
earthquakes located onshore during 2004 and 2005 have been classified by
cross-correlation, resulting in a small number of significant families. The
application of a relative location algorithm (hypoDD) revealed important
features about the spatial distribution of the earthquakes. The seismic
catalogue has been enhanced with more than 800 additional events, detected only
by the closest seismic station. These events were assigned to families by
correlation and as a consequence their hypocentral location and magnitude were
estimated by comparing them to the earthquakes of each family. The new
catalogue obtained by these methods identifies two major seismogenic zones, one
to the northwest and the other to the southwest of the Teide-Pico Viejo complex
and having a separation of at least 10 km between them. These regions alternate
their activity starting in January 2004, i.e., three months earlier than
previously thought. We propose a simple model based on the results of this work
which will also concur with all previous geophysical and geochemical studies of
the 2004 crisis. The model proposes a single magma intrusion affecting the
central part of the island with lateral dikes driven by the rifts to the
northwest and southwest.
