Geology topics

Ying-Tsong Lin

Publications and source records attributed to Ying-Tsong Lin.

5 recordsLinked to original sources

USGS2026

Acoustic measurements and modeling of sub-bottom layers on the summit of the Atlantis II Seamount

Sub-bottom profiler images taken from the summit plateau of the Atlantis II Seamount reveal distinct seabed stratigraphy, including marine sediment, limestone, and basalt layers. Acoustic reflection data also show arrivals reflecting from this sub-bottom structure. A wavenumber integration model with elastic geoacoustic properties is able to reproduce the arrival pattern of seabed reflections and particularly the phase inversion of the sub-bottom return. The reflection model suggests that the limestone layer is eroded with high porosity and possesses a lower compressional velocity than a well-cemented layer. The model results also highlight the necessity of incorporating elastic effects for realistic geoacoustic characterization.

JASA Express Letters↗

USGS2025

Isotopic compositions of modern seawater at the Mariana and Yap trenches

The isotopic composition of ocean water is crucial in studying water masses and mixing in deep oceans, isotope mass balance in ocean water regulated by high-temperature and low-temperature hydrothermal alterations, and the exchange of water among crust-ocean-mantle reservoirs. We collected 40 water samples from Challenger Deep and the water column above at the Mariana Trench (down to 10,923 m) and 12 from the Yap Trench (down to 6,300 m) in the western Pacific Ocean in three hadal cruises from 2016 to 2018. The δ 2 H values at the Mariana and Yap Trenches average 0.1 ± 0.2 ‰ (1σ error). The δ 2 H records from this study, together with existing databases, manifest that deep waters have δ 2 H values varying between −2 and +2 ‰ (except for the Weddell Sea, the Greenland, Iceland, and Norwegian Seas, and the Mediterranean Sea), with increasing values from the Southern Ocean to the Pacific and Indian Oceans, and to the Atlantic Ocean. The average δ 18 O value of water samples from both trenches is –0.04 ± 0.03 ‰ (1σ error). The correlation between δ 18 O and salinity distinguishes abyssal water masses at the study region, UCDW (Upper Circumpolar Deep Water) and LCDW (Lower Circumpolar Deep Water). These water samples from the Mariana and Yap Trenches gave an average 17 O excess value of −6 ± 1 ppm (1σ error). Our 52 data records of 17 O excess expand the 38 existing records for the deep ocean. Both δ 2 H and 17 O excess of modern ocean have rolled as anchor points to reconstruct compositions of Earth’s early ocean.

ACS Earth and Space Chemistry↗

USGS2024

Feature-based maximum entropy for geophysical properties of the seabed

The coherent recombination of a direct and seabed reflected path is sensitive to the geophysical properties of the seabed. The concept of feature-based inversion is used in the analysis of acoustic data collected on a vertical line array (VLA) on the New England continental shelf break in about 200 m of water. The analysis approach for the measurements is based on a ray approach in which a direct and bottom reflected path is recombined, resulting in constructive and destructive interference of the acoustic amplitudes with frequency. The acoustic features have the form of prominent nulls of the measured received levels as a function of frequency as a broadband (500–4500 Hz) source passes the closest point of approach to the VLA. The viscous grain shearing (VGS) model is employed to parameterize a two-layer seabed model. The most likely seabed is a sand sediment with a porosity of about 0.42. There is a possibility of a thin (less than 0.5 m) surface layer having a slightly higher porosity between 0.45 and 0.50. Using the estimates for the VGS parameters inferred from the short-range frequency features, a normal mode model is used to predict the received acoustic levels over larger range scales.

Journal of the Acoustical Society of America↗

USGS2023

Acoustic ducting by shelf water streamers at the New England shelfbreak

Greater sound speed variability has been observed at the New England shelfbreak due to a greater influence from the Gulf Stream with increased meander amplitudes and frequency of Warm Core Ring (WCR) generation. Consequently, underwater sound propagation in the area also becomes more variable. This paper presents field observations of an acoustic near-surface ducting condition induced by shelf water streamers that are related to WCRs. The field observations also reveal the subsequent disappearance of the streamer duct due to the passage of a WCR filament. These two water column conditions are investigated with sound propagation measurements and numerical simulations.

Atlantic Ocean, New England Shelfbreak↗

USGS2020

Geoacoustic inversion for a New England mud patch sediment using the silt-suspension theory of marine mud

This article provides an application of the silt-suspension theory to a Bayesian-inference inversion for the geo-acoustic parameters in marine mud. The theory, with consequences that have been developed recently, postulates a suspension of water and clay mineral card-houses that supports moderately dilute concentrations of silt particles. The approach is an example of a physically based model inversion, in which parameters representing physical mud-layer properties are obtained by inversion and used to produce estimates of geoacoustic properties, including their frequency dependence. The acoustic data are from a combustive source signal propagated along a track, located over several meters of fine-grained mud in the New England Mud Patch, to a single hydrophone on a receiver array during the 2017 Seabed Characterization Experiment. Data extracted from a nearby piston core inform the physical modeling, with selections of inversion parameters guided by both sensitivity analyses and bounds from archival and core measurements. Results show the feasibility of this inversion approach. The estimates of mud density and sound speed are close to values obtained independently. The frequency dependence of attenuation is estimated over the full low-frequency source band and has an approximate power exponent of 1.72.

IEEE Journal of Oceanic Engineering↗