The Nicaraguan Seismic Network registered in August, 1998, a number of 203 seismic events. The majority of them were located in the subduction zone of coast of the Pacific Ocean. A seismic event was felt on Augost 20 , generated by a shallow earthquake (ML=3.6) located near the towns of Villa Sandino, Santo Tomás and San Pedro de Lóbago, in the region of Chontales. A strong shallow earthquake (ML=6.4) ocurred on August23 of coast of the Pacific Ocean of Nicaragua. This event was felt by many people in the Pacific Region of Nicaragua.
On August 4, the Seismic Network registered the destructive magnitude 7 earthquake in Ecuador. Due to its large magnitued the event INETER reported the event within a few minutes to the Civil Defense of Nicaragua and the Seismic Networks of Panamá and Costa Rica.
Seismic events ocurred in the volcanoes San Cristóbal, Telica, Cerro Negro, Momotombo, Masaya and Laguna de Apoyo. The volcano‑seismic activity of San Cristóbal volcano was significantly lower than in the previous month. Also, Telica volcano showed less activity than in the month of July.
The Nicaraguan Seismic Network counts now with 20 telemetric seismic stations, 10 of them are 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.