Neotectonics of Southeast Jamaica Derived From Marine Seismic Surveys and Gravity Cores

Wright, Vashan; Hornbach, Matthew J.; Brown, Lyndon; McHugh, C. M.; Mıtchell, Sımon F.

doi:10.1029/2019tc005806

Cited by 4 publications

(3 citation statements)

References 39 publications

(107 reference statements)

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“…Where possible, we also randomly remove 1–2 control points and assess their influences on the shoreline positions. While creating the time contours, we also assume that the submarine and subaerial beach slopes remained constant over the last two centuries because (a) this is what historical elevation and bathymetric maps show, (b) deposition rates were primarily controlled by long‐shore drift and easterly winds during this period (Goreau & Burke, 1966; Wright et al., 2019), and (c) Jamaica's local sea level has remained constant for at least 425 years (Digerfeldt & Hendry, 1987). We interpolate between the contours to estimate sediment ages at sites 1–4.…”

Section: Methodsmentioning

confidence: 99%

The Effects of 180 years of Aging on the Physical and Seismic Properties of Partially Saturated Sands

Wright

Hornbach

2021

JGR Solid Earth

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Section: Methodsmentioning

confidence: 99%

The Effects of 180 years of Aging on the Physical and Seismic Properties of Partially Saturated Sands

Wright

Hornbach

2021

JGR Solid Earth

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“…Where possible, we also randomly remove 1-2 control points and assess their influences on the shoreline positions. While creating the time contours, we also assume that the submarine and subaerial beach slopes remained constant over the last two centuries because (1) this is what historical elevation and bathymetric maps show, (2) deposition rates were primarily controlled by long-shore drift and easterly winds during this period (Goreau & Burke, 1966;Wright et al, 2019), and (3) Jamaica's local sea level has remained constant for at least 425 years (Digerfeldt & Hendry, 1987). We interpolate between the contours to estimate sediment ages at sites 1-4.…”

Section: Constraining Sediment Agementioning

confidence: 99%

The effects of 180 years of aging on the physical and seismic properties of partially saturated sands

Wright¹,

Hornbach²

2022

Preprint

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Constraining how the physical properties and seismic responses of recently deposited sands change with time is important for understanding earthquake site response, subsurface fluid flow, and early stages lithification. Currently, however, there is no detailed (cm-scale) assessment of how sand physical properties and associated seismic velocities evolve over the first two centuries after deposition. Here, we integrate sedimentation rates with seismic velocity and sediment physical properties data to assess how the vadose zone sands at Port Royal Beach, Jamaica, change within 180 years after deposition. We show that compressional and shear wave velocities increase with sediment age, whereas porosity, grain size, sorting, mineralogy, and cementation fraction remain relatively unchanged during the same period. Rock physics models (constrained by the measured physical properties) predict constant seismic velocities at all sites regardless of sediment age, though misfits between modeled and observed velocities increase with sediment age. We explain these misfits by proposing that shallow sands undergo microstructural grain reorganization that leads to a more uniform distribution of grain contact forces with time. Our results imply that beach sands undergo a previously undocumented lithification process that occurs before compaction.

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“…Neotectonic deformations can be readily recognized in the Quaternary marine and lacustrine sediment successions, either as faults and folds within the stratified sediments or as secondary effects such as mass-transport deposits (MTDs, e.g., Strasser et al, 2011;Wiemer et al, 2015;Moernaut et al, 2017;Wright et al, 2019;and Ojala et al, 2019), i.e., underwater landslides. The recognition of such subsurface features in the investigated area ( Figure 9) allows insights into the long-term neotectonic activity spanning the Late Pleistocene and Holocene.…”

Section: Indicators Of Neotectonic Deformations In High-resolution Shmentioning

confidence: 99%

Active Tectonics in the Kvarner Region (External Dinarides, Croatia)—An Alternative Approach Based on Focused Geological Mapping, 3D Seismological, and Shallow Seismic Imaging Data

et al. 2020

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Active tectonics in long-lived orogenic belts usually manifests on the preexisting inherited structures. In the Kvarner region of the External Dinarides, an area with low-to-moderate seismicity related to the Adriatic microplate (Adria) northward movement, we deal with faults in predominantly carbonate rocks within tectonically complex NW-SE striking fold-and-thrust belt, which makes the identification and parametrization of the active structures challenging. Moreover, anthropogenic modifications greatly complicate access to the surface geological and geomorphological data. This paper demonstrates results of focused multidisciplinary research, from surface geological mapping and offshore shallow seismic surveys to earthquake focal mechanisms, as an active fault identification and parametrization kit, with a final goal to produce an across-methodological integrated model of the identified features in the future. Reverse, normal, and strike-slip orogen-parallel (longitudinal) to transverse faults were identified during geological mapping, but there is no clear evidence of their mutual relations and possible recent activity. The focal mechanisms calculated from the instrumental record include weak-to-moderate earthquakes and show solutions for all faulting types in the upper crust, compatible with the NE-SW oriented principal stress direction, with the stronger events favoring reverse and strike-slip faulting. The 3D spatial and temporal distribution of recent earthquake hypocenters indicate their clustering along predominantly subvertical transversal and steeply NE-dipping longitudinal planes. High-resolution shallow seismic geoacoustical survey (subbottom profiler) of the Quaternary sediments in the Rijeka Bay revealed local tectonic deformations of the stratified Late Pleistocene deposits that, along with overlaying mass-transport deposits, could imply prehistorical strong earthquake effects. Neotectonic faults onshore are tentatively recognized as highly fractured zones characterized by enhanced weathering, but there is no evidence for its recent activity. Thus, it seems that the active faults are blind and situated below the thin-skinned and highly deformed early-orogenic tectonic cover of the Adria. A strain accumulating deeper in the crust is probably irregularly redistributed near the surface along the preexisting fault network formed during the earlier phases of the Dinaric orogenesis. The results indicate a need for further multidisciplinary research that will contribute to a better seismic hazard assessment in the densely populated region that is also covered by strategic infrastructure.

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Neotectonics of Southeast Jamaica Derived From Marine Seismic Surveys and Gravity Cores

Cited by 4 publications

References 39 publications

The Effects of 180 years of Aging on the Physical and Seismic Properties of Partially Saturated Sands

The Effects of 180 years of Aging on the Physical and Seismic Properties of Partially Saturated Sands

The effects of 180 years of aging on the physical and seismic properties of partially saturated sands

Active Tectonics in the Kvarner Region (External Dinarides, Croatia)—An Alternative Approach Based on Focused Geological Mapping, 3D Seismological, and Shallow Seismic Imaging Data

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