The Nicaraguan Seismic Network registered in February, 1998, a number of
160 seismic events. The majority of
them were located in the subduction zone off coast of the Pacific Ocean. Seismic
events occurred also in the volcanoes San Cristóbal, Telica, Cerro Negro and
The seismic activity of San
Cristóbal volcano which had calmed down in Januarry, 1998, presented a
sudden increase in February reaching a new maximum, within a few days. The
character of this seismic activity has changed. The tremor which before was
practically continuous occurs now in form of fluctuations or events. These
events are following one to another in very short time distances, so that the
automatic detection routines records several hundred events per day.
seismic activity at Telica volcano maintains its high level of more than 100
events per day.
A new seismic station was installed at the rim of Tiscapa Lagoon, a
volcanic crater lake in the center of Managua.
The Nicaraguan Seismic Network counts now with 20 telemetric
seismic stations, 10 of them located in volcano complexes. The data
are digitally recorded and processed at Managua data center, which in turn has
also a set of seismometers . Any seismic event detected by the data acquisition
routine is processed regularly within a short time by the seismologist on duty.
In case of a strong event the system emits an acoustic signal and the
seismologist determines immediately the parameters of the event and sends
within minutes a report to the Nicaraguan authorities and the mass media. Any
unusual behavior of the seismic signal in the volcanoes would also be reported
to enable preventive measures against the negative effects of dangerous
phenomena in the volcanoes (beginning eruption, land slides, strong degassing).
The Monthly Bulletin is published in the first
days of the following month, after having revised the preliminary data. It is
distributed in Nicaragua to governmental organizations and mass media, in
Central America to cooperating institutions in Guatemala, El Salvador, Honduras,
Costa Rica, Panama. Furthermore it is sent to several cooperating institutions
in South America, North America and Europe. Phase data and waveforms can be
obtained writing to the address on the front page.