On February 21, 1996, an earthquake shook the northern region of Peru. This event generated a tsunami with 2-3 m height waves. From the analysis and the signal processing of 15 broadband teleseismic stations, a waveform inversion was performed to obtain the focal mechanism and source time function indicating a complex rupture process. The total duration of the rupture was 75 s, a rather high value for a relatively small earthquake. The calculated scalar seismic moment was 3.8 × 1020 Nm, which corresponds to a moment magnitude of 7.6 Mw. The slip distribution is heterogeneous, consistent with the source time function, with a maximum slip of 6.6 m around the main asperity concentrated in an area of 30×30 km2. Coseismic deformation field was calculated for 28 sub-faults, which was used as the initial condition of the tsunami propagation. Synthetics mareograms were calculated for Chimbote ...

On October 17, 1966 at 21:41 UTC, a big earthquake shooked the central region of Peru, causing 100 deaths. The maximum severity of shaking was reported in the Huacho city (VIII-IX MM). As coseismic effect a tsunami was generated, which flooded some villages and beach resorts, as Casma and Tortugas. From analysis and signal processing of three tidal records observed at stations of Chimbote, Callao and Marcona, we determined the parameters of the seismic source through an inversion process, in which the computed signal is compared with the observed signal by a non-negative least square process. The maximum slip is 4.7 m and is located in the Southern side of rupture geometry, which means that the maximum asperity or zone of greatest energy release is located under the Ocean in front of the Huacho city, this is consistent with the maximum intensity values reported. The scalar tsunami mome...

The 1994 Bolivia earthquake, with hypocenter at 641 km depth, is the greater magnitude earthquake recorded instrumentally in the last 50 years. This earthquake did not produce damage in the surface but was perceived in most of the southern hemisphere. This seismic event had a multiple (complex) rupture process during 55 s and the rupture propagated towards N-E direction with a 1.6 km/s mean velocity. The size of the rupture was around 90 km; however, the principal asperity was contained within an area of 40×40 km2. The rupture corresponds to a focal mechanism of normal type with planes oriented in the E-W direction, being the fault plane close to the vertical. The scalar seismic moment calculated by teleseismic body waveform inversion is 2.30 × 1021 Nm and corresponds to a magnitude of Mw 8.2.

El terremoto de Bolivia de 1994, con hipocentro a 641 km de profundidad, es el de mayor magnitud registrado instrumentalmente en los últimos 50 años. No produjo daños en la superficie pero fue percibido en la mayor parte del hemisferio sur. Este evento sísmico tuvo un proceso de ruptura múltiple y complejo durante 55 s y la ruptura se propagó en la dirección N-E con una velocidad promedio de 1.6 km/s. La longitud de la ruptura fue de 90 km y la aspereza principal estuvo contenida en un área de 40×40 km2. La ruptura corresponde a un mecanismo focal de tipo normal con planos orientados en dirección E-O, siendo el plano de ruptura cercano a la vertical. El momento sísmico escalar calculado mediante inversión de ondas de volumen es 2.30 × 1021 Nm y corresponde a una magnitud de 8.2 Mw.

The Earth is a dynamic system and as such is susceptible to the action of seismic and geological events. For many problems in science and engineering there is a need to establish a three-dimensional coordinate system for geodesic measurements. With the advancement of satellite geodesy, is currently possible to determine the horizontal coordinates of a point on the Earth’s surface with errors less than one centimeter. The problem arises when trying to obtain the vertical coordinate, since satellites provide heights with reference to an ellipsoid, which is not an equipotential surface. For obtaining the vertical coordinate, the reference surface of the geoid or mean level sea is taken. In the present study, a methodology to determine the mean sea level in the Paracas Bay is provided, using an ultrasonic level sensor interfaced to a computer. The data are digitally processed using filteri...