Dynamic characterization of the Mejillones Basin in northern Chile, using combined geophysical field measurements

Maringue, José; Yáñez, Gonzalo; Sáez, Estéban; Podestá, Luis; Figueroa, Ronny; Estay, N. P.; Lira, Elías

doi:10.1016/j.enggeo.2017.12.016

Cited by 9 publications

(7 citation statements)

References 25 publications

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“…1,000,000 [36]. Right panel: Main results of the geophysical campaign [8,36]. The color grid shows the gravity residuals in mGal.…”

Section: Aricamentioning

confidence: 99%

“…Specifically in this city, there is a thick sedimentary infill, composed of diatomites and some sands and silts, which is a particularly different condition compared to the rest of the northern cities in the country [45]. According to Maringue et al [8] the thickness of the sedimentary deposits reaches ~800 m with soil densities around 1.5 g/cc. The whole geophysical campaign in this zone is available in Maringue et al [8] and the main results are shown in the right panel of Figure 2 including the residual gravity (colored map) and H/V results (colored and different size circles).…”

Section: Mejillonesmentioning

confidence: 99%

“…According to Maringue et al [8] the thickness of the sedimentary deposits reaches ~800 m with soil densities around 1.5 g/cc. The whole geophysical campaign in this zone is available in Maringue et al [8] and the main results are shown in the right panel of Figure 2 including the residual gravity (colored map) and H/V results (colored and different size circles). panel of Figure 2 shows the main results of these campaigns, including the residual gravity (colored map) and H/V results (colored and different size circles).…”

Section: Mejillonesmentioning

confidence: 99%

“…The gravimetric method measures the variations in the gravity field caused by the density contrast within the soil domain and with respect to the bedrock underneath [1]. Following this simple principle, gravimetric surveys have been used in many fields such as hydrogeology, e.g., [2][3][4], mining exploration, e.g., [5,6], or geometric characterization of sedimentary basins, e.g., [7,8], among others.…”

Section: Introductionmentioning

confidence: 99%

“…In the study of sedimentary basins, many authors have combined both methods with others geophysical measurements, to conduct an integrated interpretation of their geometry and dynamic properties, and to estimate their seismic response, e.g., [7,8,[20][21][22][23][24]. In this context, the parameter in common between both methods is the inference of the depth to rocky basement.…”

Section: Introductionmentioning

confidence: 99%

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An Empirical Correlation between the Residual Gravity Anomaly and the H/V Predominant Period in Urban Areas and Its Dependence on Geology in Andean Forearc Basins

2021

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The study of site amplification effects is crucial to assess earthquake hazards that can produce great damage in urban structures. In this context, the gravity and the ambient noise horizontal-to-vertical spectral ratio (H/V) are two of the most used geophysical methods to study the properties of the subsoil, which are essential to estimate seismic amplification. Even though these methods have been used complementarily, a correlation between them has not been thoroughly studied. Understanding this correlation and how it depends on geology could be important to use one method as an estimator of the other and to make a distinction between the seismic and gravimetric basement. In this research, a comparison between the residual gravity anomaly and the H/V predominant period is performed using a long dataset from different projects on sedimentary basins in a group of the most important cities in Chile. To simplify the geological information, a seismic classification is used for soils, which considers the Vs30 and the predominant period of vibration (T0). The results of this comparison show a direct correlation between both parameters, the higher the negative residual gravity anomaly the higher the H/V predominant period. This correlation improves when only soft soils are considered, increasing the R2 value in more than a 50% in all the individual cities with respect to the overall correlation. When all the cities are considered, the R2 value for soft soils increases up to 0.87. These results suggest that the ideal geological background for this correlation is when a soft soil layer overlies a homogeneous bedrock. Heterogeneities in the bedrock and in the soil column add dispersion to the correlation. Additionally, the comparison between the depth to basement inferred by both methods show differences of less than 15% in soft sites; in denser sites, the difference increases up to 30% and the definition of a clear H/V peak is more difficult. In general, the gravimetric basement is deeper than the seismic one. However, gravimetric depths to basement can be under/over-estimated in zones with a heterogeneous soil column.

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“…1,000,000 [36]. Right panel: Main results of the geophysical campaign [8,36]. The color grid shows the gravity residuals in mGal.…”

Section: Aricamentioning

confidence: 99%

Section: Mejillonesmentioning

confidence: 99%