The PRSN currently operates about 34 seismic stations in Puerto Rico, the Dominican Republic, and the U.S. and British Virgin Islands. There are two types of stations according to their technology; there are the analog stations which consist of a sensor, a communication system, batteries and solar panel and other peripheral electronic equipment. And the digital stations that besides containing the equipment already mentioned need a digitizer.
There are three main types of sensors: Short Period, Broadband and Accelerometer. Short period and broadband stations are also known as smooth motion stations because they detect lower intensity events very well, but when they are very strong, they can become saturated. Accelerometers are considered strong motion stations because they are designed to scale up the higher intensity events.
The short period sensors are Teledyne Geotech S-13 vertical component and the Mark L-4 three component, have a natural frequency of 1 Hz. Among the broadband sensors the PRSN has the following models: CMG-40T (30s to 50 Hz), CMG-3ESP (100s to 50 Hz) and CMG-3T and the Trillium 120s PH, QA, PA, Horizon from Nanometrics. The strong motion sensors are Episensor(FBA of 2g and 4g) and Titan 4g(Nanometrics).
All signals are digitized before processing. The short time signals are digitized in the offices of the Puerto Rico Seismic Network, while the broadband and strong motion signals are digitized in the same station. The short period instruments, as well as the accelerometers, are digitized at 100 samples per second (sps), while the broadband instruments are digitized at 100 samples per second (sps). Digitizers from Nanometrics, Refraction Technology (Reftek), Q330 Kinemetrics and Data Acquisition Systems are used to digitize the broadband stations.
For the transmission of data, in real time, radios in the VHF, UHF bands are used. Spread spectrum radios, microwave, satellite transmission and Internet are also used. The data from the stations is sent directly or through repeaters to Mayagüez. There are three repeater stations: Cerro La Santa in Guavate, Cerro Santa Ana in Maricao and Cerro Punta in Jayuya. At these repeaters, the signals from the stations are combined and retransmitted. In Tortola BVI, the data is transmitted via Internet, in Anegada BVI, it is transmitted via Satellite.
The PRSN also has 18 permanent GPS (Global Position System) stations, located in Puerto Rico, adjacent islands and American and British Virgin Islands. The acquisition instruments are from the company Trimble (Alloy, NetRS and NetR9) and Topcon. Also the RSPR operates 7 tide gauges located in the coasts of Puerto Rico, adjacent islands and British Virgin Islands. The data acquisition equipment for the tide gauges is from the company Sutron (SatLink, Xpert), the company AquatraK (Sensor Aquatrak) and YSI (NILE-502 Radar).
All signals are received and stored in the PRSN offices located on the University Campus of Mayagüez. All data are processed digitally and incorporated into a database. In many of the broadband stations there is also a temporary data recording in the field or in the repeater.
This table lists our seismic stations and accelerometers. If you want to view a full list of stations, including those from other regions, please use our Station Monitoring Tool