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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 plate and the Caribbean plate, resulting in a series of fold-and-thrust belts and active fault zones. In order to solve the regional structure of western Hispaniola, several seismic imaging studies have been conducted using receiver function and local earthquake tomography. These studies combined with geological observations give the outline of crustal structure in the area, showing a thinner crust (~20 km) in the northern and southern domains and a thicker crust (~40 km) in the central part of western Hispaniola. However, the resolution of these results is limited. Receiver function is only sensitive to the structural discontinuities beneath stations, whereas local earthquake tomography is restricted by the earthquake observation, in which event detection in this region has been shown to be a challenging task due to high background noise. Therefore, in this study, to investigate the crustal structure across western Hispaniola, we perform multi-component noise cross-correlation and measure Rayleigh wave phase velocity and ellipticity (i.e., horizontal-to-vertical (H/V) amplitude ratio) between the period of 2-20 s. The data used in this study are mainly from 27 broadband stations in western Hispaniola that were deployed from April 2013 to June 2014 during the Trans-Haiti project. Additionally, we include all available stations within 1,000 km from the target area to provide constraints on longer-period signals. The preliminary results of H/V show consistent patterns related to geology, in which sedimentary basins show high H/V whereas mountain areas show low H/V, implying different elastic responses of Rayleigh waves in different geological units. We will then combine H/V and phase velocity measurements to invert for a 2-D shear velocity across western Hispaniola. The results from this study will provide useful insights into seismic hazard assessment in this area, which has recently experienced two devastating earthquakes in 2010 and 2021.

Session: Crustal Imaging of High Seismic Hazard Regions [Poster]

Type: Poster

Date: 4/20/2023

Presentation Time: 08:00 AM (local time)

Presenting Author: Hsin-Yu Lee

Student Presenter: Yes

Invited Presentation: 

Authors