Geomorphology Characterization of Ica Basin and Its Influence on the Dynamic Response of Soils for Urban Seismic Hazards in Ica, Peru

Abstract

We evaluated the influence of the geomorphology of Peru's Ica Basin on the dynamic response of soils of the city of Ica. We applied five geophysical methods: spectral ratio ( / ), frequency-wavenumber ( -), multichannel analysis of surface waves (MASW), multichannel analysis of microtremor (MAM), and Gravimetric Analysis. Our results indicate that the soils respond to two frequency ranges: 0 (0.4-0.8 Hz) and 1 (1.0-3.0 Hz). The -, which considers circular arrays, shows two tendencies with a jump between 1.0 and 2.0 Hz. MASW and MAM contribute to frequencies greater than 2.0 Hz. The inversion curve indicates the presence of three layers of 4, 16, and 60 m with velocities of 180, 250, and 400 m/s. The Bouguer anomalies vary between −17.72 and −24.32 mGal and with the spectral analysis we identified two deposits, of 60 m and 150 m of thickness. Likewise, the relationship between the velocities of 400 and 900 m/s, with the frequency = 1.5 Hz, allows us to determine the thickness for the layers of 60 (slightly alluvial to moderately compact) and 150 m (soil-rock interface). These results suggest that the morphology of the Ica Basin plays an important role in the dynamic behavior of the soils to low frequency.

3-D seismic travel-time tomography validation of a detailed subsurface model: a case study of the Záncara river basin (Cuenca, Spain)

“…This interface puts in contact the lutites layer with the next lithology identified in the core samples. This fact suggests that the layers dip gently to the west supporting the wedge geometry observed in the tomographic model and following the regional-scale geologic interpretations (Biete et al, 2012;Piña-Varas et al, 2013).…”

“…4). The latter was also suggested by the regional-scale geology and other geophysical studies (Biete et al, 2012;Piña-Varas et al, 2013).…”

“…The crustal structure of the Iberian Chain has gathered academic interest since the early 1990s (see Seillé et al, 2015;Guimerà et al, 2016, and references therein), including the acquisition of local and regional geologic and geophysical studies of the Loranca Basin (Biete et al, 2012;Piña-Varas et al, 2013). The Loranca Basin comprises syntectonic Cenozoic strata (Guimerà et al, 2004).…”

“…It is also critical in civil engineering and monitoring of underground structures (Escuder Viruete et al, 2003;Malehmir et al, 2007;Juhlin et al, 2007;Martí et al, 2008;Giese et al, 2009;Alcalde et al, 2013a). In addition, the implementation of a competent subsurface exploration scheme is very valuable for assessing and providing detailed site characterization for addressing natural hazards, e.g., seismic hazard (Samyn et al, 2012;Ugalde et al, 2013;Wadas et al, 2017;Bernal et al, 2018). Typical geotechnical practice for subsurface exploration has often relied on a combination of drilling, in situ testing, geophysical surveys and laboratory analysis of field samples (Andara et al, 2011;Kazemeini et al, 2010;Alcalde et al, 2014).…”

3D Seismic Traveltime Tomography Validation of a Detailed Subsurface Model: The case study of the Zancara River Basin (Cuenca, Spain)

“…Thus, understanding its composition and structure is a regular objective in studies such as: natural resource exploration [Davis et al, 2003;Place et al, 2015] and environmental assessment studies [Steeples, 2001;Zelt et al, 2006)] It is also critical in civil engineering practice and monitoring of underground structures [Escuder-Viruete et al, 2003;Malehmir et al, 2007;Juhlin et al, 2007;Martí et al, 2008;Giese et al, 2009;Alcalde et al, 2013a]. In addition, the implementation of a competent subsurface exploration scheme is very valuable for assessing and/or providing detailed site characterization for addressing natural hazards, e.g., seismic hazard [Samyn et al 2012;Ugalde et al, 2013;Wadas et al, 2017;Bernal et al, 2018]. Typical geotechnical practice for subsurface exploration has often relied on a combination of drilling, in situ testing, geophysical surveys, and laboratory analysis of field samples [Andara et al, 2011;Kazemeini et al, 2010;Alcalde et al, 2014].…”