Seismic Microzonation: A Comparison between Geotechnical and Seismological Approaches in Pointe-à-Pitre (French West Indies)

Lebrun, B.; Duval, Anne-Marie; Bard, Pierre‐Yves; Monge, Olivier; Bour, M.; Vidal, Sylvain; Fabriol, H.

doi:10.1023/b:beee.0000038949.91495.91

Cited by 18 publications

(10 citation statements)

References 6 publications

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“…The H/V curves determined from the onland seismic data can be categorized into several general types (LeBrun et al 2004). Similar patterns can also be observed for the H/V curves estimated from the ambient noises based on the OBS records.…”

Section: Resultssupporting

confidence: 60%

“…The principle is to evaluate spectral ratios, from which the peak site frequency (fundamental frequency) and the associated amplification factor could be determined. This method has been widely utilized for the onland area, including the determination of seismic microzonation (Bour et al 1998;Lee et al 2001;LeBrun et al 2004), seismic site effect evaluation (e.g., Sokolov et al 2007), bedrock depth mapping (Ibs-von Seht and Wohlenberg 1999), and shallow soil shear-wave velocity structure profiling (e.g., Scherbaum et al 2003), etc. However, few studies have been introduced for the marine area, where site characterizations are even more difficult to investigate than those onland.…”

Section: Introductionmentioning

confidence: 99%

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Seismic site response of submarine slope offshore southwestern Taiwan

Lin¹,

Chen²,

Su³

et al. 2018

Terr. Atmos. Ocean. Sci.

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Widely distributed Bottom-Simulating Reflectors (BSRs) have been observed in the area offshore of southwestern Taiwan where the active accretionary complex meets with the passive China continental margin. In order to clarify the link between seismic site response and sedimentary properties of submarine slope, we evaluate the response of seafloor sediments in regard to passive dynamic loads. The local site effect produced by shallow marine sediments was characterized by estimating the horizontal-to-vertical (H/V) spectral ratios of data recorded by the short-period Ocean Bottom Seismometers (OBSs). The results show that the maximal H/V ratios appeared in the range of 3.66 -9.28 Hz, suggesting that the fundamental frequency is dominated by the effect related to the very shallow sediments. For most stations, the H/V ratios estimated based on the earthquakes and noise records were characterized by different patterns. Relatively broad H/V pattern was obtained when the signals were extracted from earthquakes. This phenomenon may be related to soil nonlinearity when a stronger motion applies. In comparison with the available geological structures and bulk density distribution obtained from coring experiments, we found a relatively higher fundamental frequency of about 8 -9 Hz for the more rigid material, such as mud diapir and folding axes. For most of the area along the slope, the fundamental frequency shows a relatively low value, about 6 -8 Hz. Finally, when a site is characterized by thick or lowest bulk density sedimentary layer, we observed a fundamental frequency lower than 5 Hz, which is the lowest in our assessment.

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Section: Resultssupporting

confidence: 60%

Section: Introductionmentioning

confidence: 99%

Seismic site response of submarine slope offshore southwestern Taiwan

Lin¹,

Chen²,

Su³

et al. 2018

Terr. Atmos. Ocean. Sci.

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“…This network was progressively extended between 1998 and 2001. At its greatest extent it comprised 16 instruments (eight SM-2s and eight Kinemetrics K2s) and it permitted the study of site effects at 24 different sites in the region (see Le Brun et al [2001] and Lebrun et al [2004] who study the data with respect to microzonation of the region). This network still operates but it has been reduced to five stations; the other instruments have been In the framework of a project to create a Centre of Seismological Data of the Antilles (CDSA), it is planned to install eight new stations in order to augment the RAP by using identical instruments.…”

Section: Strong-motion Network On Guadeloupementioning

confidence: 99%

“…Recent studies [Gagnepain-Beyneix et al, 1995, Castro et al, 2003 have demonstrated that in regions of complex geology and topography the use of local accelerometric networks can lead to a better estimation of site effects due to very local conditions and are a good complementary tool to classical microzonation [Lebrun et al, 2004]. In this framework, the strong-motion networks recently installed on Guadeloupe and Martinique are essential.…”

Section: Site Effects At Strong-motion Stationsmentioning

confidence: 99%

A preliminary investigation of strong-motion data from the French Antilles

et al. 2006

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Strong-motion networks have been operating in the Caribbean region since the 1970s, however, until the mid-1990s only a few analogue stations were operational and the quantity of data recorded was very low. Since the mid-1990s, digital accelerometric networks have been established on islands within the region. At present there are thought to be about 160 stations operating in this region with a handful on Cuba, 65 on the French Antilles (mainly Guadeloupe and Martinique), eight on Jamaica, 78 on Puerto Rico (plus others on adjacent islands) and four on Trinidad.After briefly summarising the available data from the Caribbean islands, this article is mainly concerned with analysing the data that has been recorded by the networks operating on the French Antilles in terms of their distribution with respect to magnitude, source-to-site distance, focal depth and event type; site effects at certain stations; and also with respect to their predictability by ground motion estimation equations developed using data from different regions of the world. More than 300 good quality triaxial acceleration time-histories have been recorded on Guadeloupe and Martinique at a large number of stations from earthquakes with moment magnitudes larger than 4.8, however, most of the records are from considerable source-to-site distances. From the data available it is found that many of the commonly-used ground motion estimation equations for shallow crustal earthquakes poorly estimate the observed ground motions on the two islands; ground motions on Guadeloupe and Martinique have smaller amplitudes and are more variable than expected. This difference could be due to regional dependence of ground motions because of, for example, differing tectonics or crustal structures or because the ground motions so far recorded are, in general, from smaller earthquakes and greater distances than the range of applicability of the investigated equations.

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“…Lebrun et al, 2004, and references therein). These projects have shown that site amplifications on these islands can be large and highly variable between sites with similar surface geology.…”

Section: Unadjusted Empirical Ground-motion Models On Rock Plus Site mentioning

confidence: 99%

Inferred ground motions on Guadeloupe during the 2004 Les Saintes earthquake

Douglas

2007

Bull Earthquake Eng

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Accurate estimates of the ground motions that occurred during damaging earthquakes are a vital part of many aspects of earthquake engineering, such as the study of the size and cause of the uncertainties within earthquake risk assessments. This article compares a number of methods to estimate the ground shaking that occurred on Guadeloupe (French Antilles) during the 21st November 2004 (M w 6.3) Les Saintes earthquake, with the aim of providing more accurate shaking estimates for the investigation of the sources of uncertainties within loss evaluations, based on damage data from this event. The various techniques make differing use of the available ground-motion recordings of this earthquake and by consequence the estimates obtained by the different approaches are associated with differing uncertainties. Ground motions on the French Antilles are affected by strong local site effects, which have been extensively investigated in previous studies. In this article, use is made of these studies in order to improve the shaking estimates. It is shown that the simple methods neglecting the spatial correlation of earthquake shaking lead to uncertainties similar to those predicted by empirical ground-motion models and that these are uniform across the whole of Guadeloupe. In contrast, methods (such as the ShakeMap approach) that take account of the spatial correlation in motions demonstrate that shaking within roughly 10 km of a recording station (covering a significant portion of the investigated area) can be defined with reasonable accuracy but that motions at more distant points are not well constrained.

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Seismic Microzonation: A Comparison between Geotechnical and Seismological Approaches in Pointe-à-Pitre (French West Indies)

Cited by 18 publications

References 6 publications

Seismic site response of submarine slope offshore southwestern Taiwan

Seismic site response of submarine slope offshore southwestern Taiwan

A preliminary investigation of strong-motion data from the French Antilles

Inferred ground motions on Guadeloupe during the 2004 Les Saintes earthquake

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