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Imaging the Deformation Belt of Western Hispaniola Using Multi-Component Ambient Noise Cross-Correlations

Description: 

Hispaniola Island is located at a complex boundary between the North American and Caribbean plates, resulting in a series of fold-and-thrust belts and active fault zones. Several seismic imaging studies have been conducted to understand the regional structure of Hispaniola. These studies, combined with geological observations, provide an outline of the crustal structure in the area, revealing thinner crust (~20km) in the northern and southern domains and a thicker crust (~40km) in the central part of western Hispaniola. However, the resolution of these results is limited. Receiver function analysis is only sensitive to the structural discontinuities beneath stations, whereas local earthquake tomography is restricted by earthquake observations, in which event detection in this region is challenging.

Therefore, in this study, we investigate the crustal structure across western Hispaniola (Haiti) using a different approach. We perform multi-component noise cross-correlation and measure Rayleigh wave phase velocity and ellipticity (horizontal-to-vertical (H/V) amplitude ratio) within the period range of 3-18 s. The data used in this study are mainly from 27 broadband stations deployed from April 2013 to June 2014 along a north-south transect across the island. The H/V and phase velocity results exhibit consistent patterns related to the geology and tectonics of this region. Sedimentary basins exhibit higher H/V values, while mountain areas show lower H/V. In terms of phase velocity, higher velocities are observed in stations located in northern and southern Haiti, likely reflecting the more mafic crust composition compared to the lower velocities observed in the central part. We also conduct a joint inversion of H/V and phase velocity to construct a 2-D shear wave velocity model across western Hispaniola. This 2-D shear velocity model provides more constraints on the shallower crust (< 5km). A better understanding on the shallow crustal structure is particularly important for seismic hazard assessment in this area, which has recently experienced two major earthquakes in 2010 and 2021.

Session: Earth’s Structure from the Crust to the Core [Poster Session]

Type: Poster

Date: 5/2/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Hsin-Yu

Student Presenter: Yes

Invited Presentation: 

Authors