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Bolivia Networks and Seismicity Gonzalo Fernández Observatorio San Calixto, La Paz - Bolivia. Email:[email protected] Introduction.The Observatorio San Calixto is a nonprofit institution that executed the seismic and infrasound monitoring around Bolivia, during 102 years there is not any day without submitting a seismic bulletin. Bolivia hosts three IMS station, one primary seismic station PS06, one auxiliary seismic station AS08 and one infrasound station IS08 which are operated by Observatorio San Calixto thus we are the National Data Center. Brief Description of National Seismic Network.Our seismic network around LPAZ have four seismic short period vertical component stations which work with the French (CEA/DASE) cooperation, in addition the infrasound station IS08 is also under the French cooperation. At Bolivian oriental part is located the AS08 seismic station which runs three short period sensors (Z, N-S, E-O) and three long period sensors (Z, N-S, E-O) at the Bolivian south part the station MOC runs three short period sensor (Z, N-S, E-O). Both stations are under the French cooperation (CEA/DASE). LPAZ station has one broad band three component sensor and one short period one component sensor, this station works with the US (AFTAC) cooperation. Unfortunate our new digital seismic network does not work because of cooperation problems with a Telecom company, it worked from 2011 to 2013, the low collaboration with the telecom company forced us to stop the project stopping the work of 18 seismic stations. Seismic Stations Station Name Station Code Latitude Banderani BBOB -16.141829 Longitude Elevation Installed since -68.132467 3911 1975 Gloria BBOD -16.637430 -68.598088 4235 1983 Chanca BBOE -16.812908 -67.983326 4325 1982 Jacaque BBOJ -16.975080 -68.191520 4125 2008 LPAZ PS06 -16.2844 -68.1289 4810 -16.2844 -68.1287 4810 1993 OSC BS00 -16.49394 -68.13437 3640 2015 San Ignacio AS08 -15.9877 -61.0703 520 1988 Mochara MOC -21.2542 -65.6394 3580 1985 Type of Instrument Network Transmision Type ZM - 500 short period sensor OSC vertical component ZM - 500 short period sensor OSC vertical component Telemetric - Analog ZM - 500 short period sensor OSC vertical component ZM - 500 short period sensor OSC vertical component KS54000 - three components Broad Band borehole sensor OSC Telemetric - Digital GS-21 one component borehole sensor Short period three component OSC IP station ZM-500 short period sensor OSC vertical component ZM-500 short period sensor OSC East - West component ZM-500 short period sensor OSC North - South component VSAT - VPN MPLS LM-500 Long Period Vertical Component OSC LM-500 Long Period East - West OSC Component LM-500 Long Period North - South OSC Component ZM-500 short period sensor OSC vertical component ZM-500 short period sensor OSC VSAT - VPN MPLS East - West component ZM-500 short period sensor OSC North - South component Infrasound Stations Station Name Peñas Station Code Latitude IS08 H1 -16.215297 Longitude Elevation Installed since -68.453478 4042 IS08 H2 -16.202448 -68.456145 4032 IS08 H3 -16.217554 -68.442927 4071 IS08 H4 -16.221751 -68.463800 4017 1998 Type of Instrument MB2000 Microbarometer Table 1. Main Characteristic of our seismic Network. Figure 1. Seismic Network in Bolivia. Network Transmision Type OSC Telemetric - Digital Bolivian Seismicity.The Bolivian seismic activity is characteristic for the dynamic and cinematic process in internal earth, where the seismicity is originated as: Sesimogenic Sources according the origin: - - - The seismogenic sources in the Crust associated to the continental deformation: For this kind of sources the earthquakes considered have the depth lower than 75Km, this depth belongs to Bolivian crust thickness. Sub – Source related to the potentially active faults that has generated seismicity: Probably in the Holocen age (quaternary period), their evidences can be seen around the surface and can be identified due the geologic features, geomorphologic and structural presents in the current sediments, also the characterization can be obtained with the Geodesy and Pale seismicity, they will allow us to know the kind of fault, the moving average, the shift length, the likely magnitude and the return period, which can be hundreds of years or thousands of years (Brooks et al 2010, Ramírez, et al 2009). Sub Source with seismicity in different crustal plates: generally located to depths greater than 5Km, they are frequently and the magnitudes are lower than the last one, this kind of earthquakes happens around Cochabamba department Seismogenics Sources related to the Subduction Process: The earthquakes from this seismogenics source are located inside the Nazca Plate, they are originated due the subduction process, the earthquake activity at this seismogenic source is not continuously because there are not earthquakes between 500Km to 700Km depth, the main characteristic is the distribution in depth from 100km to 700Km, and the subductions earthquakes have two different sources: - - Sub Seismogenic Source located between a depth from 100km to 350Km: Also known as intermediate earthquake, the occurrence frequency is greatest than the subduction earthquakes, we can find them around La Paz (south west), Oruro and Potosi Department. The sub subduction source for earthquakes that happens at depths between 500Km to 700K:, Known as depth earthquakes, the main characteristic is that they do not happen all the time but they can generate a big magnitude earthquake, as an example, the earthquake of 09-06-1994 a 8 Mw Magnitude, it happened under 635Km of Rurrenabaque, Beni department, the occurrence is under La Paz (north), Santa Cruz and Tarija Departments.. Far Away Sources: This kind of seismogenic source is located at the contact zone between two plates, Nazca and South America, the depth is between 20Km to 50Km. The earthquakes happen as mainly result due Nazca and South America rubbing and friction (the subduction process). The second origins belongs to the subduction earthquakes with depths from 75Km to 200Km. The following maps shows the earthquakes with magnitude above 6 from 1960 and magnitude above 4 since 1994. Figure 2. Seismicity in Bolivia since 1960 with Magnitudes higher than 6. Figure 3. Seismicity in Bolivia since 1994 with Magnitudes higher than 4.