Browsing by Author "Mercado, Arturo"
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Item Restricted Analysis and Evaluation of Recent Deformation on the Huaytapallana Fault (Central Region of Peru) Based on Data Obtained from a Local Seismic Network(Seismological Society of America, 2024-11-14) Tavera, Hernando; Nina Figueroa, Vilma; Bernal Esquia, Yesenia Isabel; Mercado, ArturoIn the central region of Peru, two earthquakes with magnitudes of ==$M$==ₛ 5.6 and 6.2 occurred in 1969, originating from the Huaytapallana fault. As a result, two fault scarps formed on the surface: the first measuring 4 km and the second one 9.5 km in length, separated by a 4 km section without a surface scarp. A three‐year seismic campaign (2015–2018) conducted around the Huaytapallana fault has provided insights into its current dynamics. The 172 microearthquakes recorded, with magnitudes ranging from ==$M$==w 0.6 to 3.1, are distributed along the northeastern flank of the fault and extend over 40 km, including segments without visible surface scarps. The Huaytapallana fault is estimated to have a depth of around 15 km with a dip of 60° toward the northeast. The composite focal mechanisms indicate a deformation process due to compression, with a fault plane oriented in the north‐northwest–south‐southeast direction and dipping toward the northeast at angles between 55° and 60°. The ==$M$==w 4.7 earthquake in 2022 and its series of aftershocks exhibit a similar deformation pattern associated with the Huaytapallana fault. These results are consistent with the regional tectonics, which control the deformation processes in the Mantaro basin, originating from the convergence of the Nazca and South American plates. We consider that the significant microseismic activity occurring in areas without visible surface scarps suggests the accumulation of substantial deformation, which could lead to future earthquakes of greater magnitude that may cause significant surface displacements.Item Open Access Características del sismo de Barranca - Datem del Marañón del 03 de febrero 2022 (M6.8) y niveles de sacudimiento del suelo(Instituto Geofísico del Perú, 2022-02) Tavera, Hernando; Mamani, Cristian; Mercado, ArturoEl 03 de febrero 2022, en el distrito de Barranca, provincia de Datem del Marañón, región Loreto ocurre un sismo de magnitud M6.8 a una profundad de 139 km, llegando a ser percibido el sacudimiento del suelo en un radio de 600 km. Este sismo tuvo su origen en el proceso de deformación interna de la placa de Nazca que de desplaza por debajo del continente. Las mayores aceleraciones del suelo fueron registradas en las regiones de Amazonas, San Martin y Loreto, dentro de un área de radio igual a 200 km. Los valores de aceleración máxima del suelo oscilaron entre 58 a 98 cm/seg²; es decir, un 40 a 50% menor al sacudimiento producido durante la ocurrencia del sismo de Datem del Marañón del año 2021 (M7.5). En una área cercana a la zona epicentral, este evento sísmico incremento los daños en las viviendas afectadas por el sismo del 28 de noviembre 2021 (M7.5) ocurrido en la misma provincia de Datem del Marañón.Item Restricted Loreto intermediate depth earthquake of 26 May 2019 (Northeast Peru): source parameters by inversion of local to regional waveforms and strong‐motion observations(Seismological Society of America, 2021-07-07) Tavera, Hernando; Delouis, Bertrand; Mercado, Arturo; Portugal, DavidThe Loreto earthquake of 26 May 2019 occurred below the extreme northeast part of Peru at a depth of 140 km within the subducting Nazca plate at a distance of 700 km from the trench Peru–Chile. The orientation of the seismic source was obtained from waveform inversion in the near field using velocity and strong‐motion data. The rupture occurred in normal faulting corresponding to a tensional process with T axis oriented in east west direction similar to the direction of convergence between the Nazca and South America plates. The analysis of the strong‐motion data shows that the levels of ground shaking are very heterogeneous with values greater than 50 Gal up to distances of 300 km; the maximum recorded acceleration of 122 Gal at a distance of 100 km from the epicenter. The Loreto earthquake is classified as a large extensional event in the descending Nazca slab in the transition from flat‐slab geometry to greater dip.Item Open Access Sismo del Datem del Marañon del 28 de noviembre 2021 (M7.5) y niveles de sacudimiento del suelo(Instituto Geofísico del Perú, 2021-11) Tavera, Hernando; Mamani, Cristian; Mercado, ArturoEl 28 de noviembre 2021, en la provincia del Datem del Marañón (Loreto) ocurre un sismo de magnitud M7.5 con epicentro a 98 km al Este de la localidad de Santa Maria de Nieva. Este sismo de foco intermedio, tiene su origen en el proceso de deformación interna de la placa de Nazca a una profundidad de 131 km. Las mayores aceleraciones del suelo fueron registradas en las regiones de Amazonas, San Martin y Loreto, dentro de un área de radio igual a 250 km. Los valores de aceleración máxima oscilaron entre 100 a 194 cm/seg². Los daños y efectos producidos por el sismo del Datem del Marañón fueron muy variados y puntuales, siendo los principales la presencia de fisuras y colapso de algunas viviendas construidas con adobe y madera; además de deslizamientos de tierra y piedras en zonas de pendiente alta acompañados de procesos de licuación de suelos en carreteras.