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At least 343 records · Page 19Linked to original sources

USGS2018

Probabilistic models of seafloor composition using multispectral acoustic backscatter: The benthic detectorists

We describe and compare two probabilistic models for task-specific seafloor characterization based on multispectral backscatter. We examine whether generative or discriminative approaches to supervised seafloor characterization do better at harnessing the greatly increased information about seafloor substrate composition that is encoded in the backscattering response across multiple frequencies. A Gaussian mixture model (GMM) is proposed as a generative model, and a fully-connected conditional random field (CRF) is proposed as a discriminative model. Either model uses input data derived from monospectral or multispectral backscatter without modification. The CRF approach considers both the relative backscatter magnitudes of different substrates as well as their relative proximity, and can be optimized using parameters. The GMM model, in contrast, includes no spatial information in its estimates, being based solely on relative backscatter magnitudes. Both GMM and CRF modeling approaches perform better with multispectral backscatter compared to monospectral, significantly outperforming all three monospectral frequencies. With multispectral backscatter inputs, based on average classification accuracies alone, there was little to choose between the two modeling approaches (classification accuracy of 81% and 83% for GMM and CRF models, respectively, evaluated using 50% of available bed observations to train and 50% to test the models). However, a CRF model that has been optimized with respect to its tunable parameters tends to produce higher posterior probabilities (i.e. greater certainty) for its classifications. Using monospectral backscatter inputs, the CRF model significantly outperformed the GMM model in terms of average classification accuracy. On balance, therefore, based on the evidence presented here, the CRF is suggested to be the superior approach for task-specific seafloor classification. Although further work using additional data is required to further examine this conclusion, the work presented here will guide and focus subsequent research efforts as more areas of the seafloor are mapped with the new technology. In order to facilitate these efforts, the algorithms presented here are encoded in a freely available python toolbox for Probabilistic acoustic Sediment Mapping, called PriSM , that can be used for both monospectral and multispectral backscatter. Finally, we show that application of the CRF model to the outputs of a geoacoustical model of seafloor scattering results in realistic substrate classification boundaries. This hybrid CRF and physics-based approach can predict the physical properties of the seafloor at a finer spatial resolution than is possible using the geoacoustical model alone.

Conference Paper↗

USGS2020

Gas hydrate saturation estimation from acoustic log data in the 2018 Alaska North Slope Hydrate-01 stratigraphic test well

Completed in December 2018, the Alaska North Slope Hydrate 01 stratigraphic test well provides a wealth of logging-while-drilling (LWD) data for strata to below the base of gas hydrate stability (BGHS). This well is intended to be the first of three wells drilled for a long-term gas hydrate production test to be conducted by the U.S. Department of Energy National Energy Technology Laboratory, the Japan Oil, Gas and Metals National Corporation, and the U.S. Geological Survey (USGS). The Hydrate 01 stratigraphic test well confirmed the presence of gas hydrate in two sand reservoirs within the hydrate stability zone, indicating the suitability of this location for a long-term gas hydrate production test. The USGS, using an effective-medium-theory rock-physics approach, has estimated gas hydrate saturations from compressional (P) and shear (S) wave log data acquired in the Hydrate 01 well. We assume that gas hydrate occurs as pore-filling load-bearing material (i.e., part of the grain matrix). For Unit D, approximately 500 feet above the BGHS, both P-wave and S-wave acoustic logs indicate high gas hydrate saturations with S-wave results slightly lower than those for P-waves. For Unit B, located just above the BGHS, we obtain high gas hydrate saturation estimates from both sonic logs. Our P-wave saturation estimates agree well with results from electrical-resistivity-based estimates, whereas estimates from nuclear magnetic resonance LWD data generally suggest 5 to 10 percent higher saturations; our S-wave results suggest lower saturations. These differences likely indicate complexities in the form of gas hydrate occurrence within the sediment pore space, potentially including differences between hydrate occurrence in Units B and D.

Alaska↗

USGS2020

Case Study 4: NABat acoustic monitoring allows inferences about bat populations at multiple scales

North American bats face unprecedented risks from continuing and emerging threats including white-nose syndrome, wind energy development, and habitat loss. Many species of bats are thought to be recently experiencing unparalleled population declines unlike any previously observed (O’Shea et al. 2016). The North American Bat Monitoring Program (NABat) was conceived to better understand the true ecological consequences of these large-scale population reductions (Loeb et al. 2015). NABat aims is to improve the state of conservation science for the 47 species of bats shared by Canada, United States, and Mexico. To meet this objective, NABat offers standardize protocols and a unifying sample design facilitating a multi-agency, multinational, collaborative monitoring effort. A key element of NABat is cross-boundary partner coordination and sharing of limited resources for the collection of bat echolocation data. Here we provide three compelling examples of how NABat provides a convenient framework for using acoustic data to assess the potential impacts of current and future threats to North American bats across multiple spatial scales.

Oregon↗

USGS2023

Preliminary analysis of a horizontal multifrequency hydroacoustic device designed for surrogate measurements of suspended sediment concentration: The Horizontal Acoustic Sediment Current Profiler

Single frequency active hydroacoustic measurements have been correlated with suspended sediment concentration. In river systems that include widely varying suspended sediment particle sizes, a multi-frequency hydroacoustic approach has increased predictive capabilities. However, the multi-frequency approach requires installation and operation of multiple sensors in a river channel and relies on technology previously designed for measuring water velocity. The Horizontal Acoustic Sediment Current Profiler (HASCP) is a single unit multi-frequency (500, 1,500, and 2,000 mHz) hydroacoustic sensor that was designed to target suspended sediment concentrations. The HASCP was briefly deployed in the Rio Grande at Albuquerque, NM, USGS gage in 2021 and is currently (2022) in operation at the Colorado River near Cameo, CO gage. Results of preliminary testing of the HASCP are presented in this paper.

Conference Paper↗

USGS2004

Strength and acoustic properties of Ottawa sand containing laboratory-formed methane gas hydrate

Although gas hydrate occurs in a wide variety of sediment types and is present and even pervasive at some locations on continental margins, little is known about how it forms naturally. Physical properties of the resultant gas hydrate-sediment mixtures, data needed for input into models that predict location and quantity of in situ hydrate are also lacking. Not only do properties of the host materials influence the type and quantity of hydrate formed and whether a particular deposit may be an economic resource or a geohazard, the properties of the natural sediment are also subsequently changed by the formation of gas hydrate in the pore space. The magnitude of the change is primarily related to the amount and the weighted inter-particle distribution of the hydrate deposits in relation to the actual sediment grains. Our goal is to understand the interaction between natural sediments and gas hydrate formation in order to quantify physical properties that are useful to predictive models.

Book chapter↗

USGS2015

Acoustical deterrence of Silver Carp ( Hypophthalmichthys molitrix )

The invasive Silver Carp ( Hypophthalmichthys molitrix ) dominate large regions of the Mississippi River drainage and continue to expand their range northward threatening the Laurentian Great Lakes. This study found that complex broadband sound (0–10 kHz) is effective in altering the behavior of Silver Carp with implications for deterrent barriers or potential control measures (e.g., herding fish into nets). The phonotaxic response of Silver Carp was investigated using controlled experiments in outdoor concrete ponds (10 × 4.9 × 1.2 m). Pure tones (500–2000 Hz) and complex sound (underwater field recordings of outboard motors) were broadcast using underwater speakers. Silver Carp always reacted to the complex sounds by exhibiting negative phonotaxis to the sound source and by alternating speaker location, Silver Carp could be directed consistently, up to 37 consecutive times, to opposite ends of the large outdoor pond. However, fish habituated quickly to pure tones, reacting to only approximately 5 % of these presentations and never showed more than two consecutive responses. Previous studies have demonstrated the success of sound barriers in preventing Silver Carp movement using pure tones and this research suggests that a complex sound stimulus would be an even more effective deterrent.

Biological Invasions↗

USGS2008

Estimating pore-space gas hydrate saturations from well log acoustic data

Relating pore-space gas hydrate saturation to sonic velocity data is important for remotely estimating gas hydrate concentration in sediment. In the present study, sonic velocities of gas hydrate–bearing sands are modeled using a three-phase Biot-type theory in which sand, gas hydrate, and pore fluid form three homogeneous, interwoven frameworks. This theory is developed using well log compressional and shear wave velocity data from the Mallik 5L-38 permafrost gas hydrate research well in Canada and applied to well log data from hydrate-bearing sands in the Alaskan permafrost, Gulf of Mexico, and northern Cascadia margin. Velocity-based gas hydrate saturation estimates are in good agreement with Nuclear Magneto Resonance and resistivity log estimates over the complete range of observed gas hydrate saturations.

Geochemistry, Geophysics, Geosystems↗

USGS2008

Seismic and acoustic recordings of an unusually large rockfall at Mount St. Helens, Washington

On 29 May 2006 a large rockfall off the Mount St. Helens lava dome produced an atmospheric plume that was reported by airplane pilots to have risen to 6,000 m above sea level and interpreted to be a result of an explosive event. However, subsequent field reconnaissance found no evidence of a ballistic field, indicating that there was no explosive component. The rockfall produced complex seismic and infrasonic signals, with the latter recorded at sites 0.6 and 13.4 km from the source. An unusual, very long-period (50 s) infrasonic signal was recorded, a signal we model as the result of air displacement. Two high-frequency infrasonic signals are inferred to result from the initial contact of a rock slab with the ground and from interaction of displaced air with a depression at the base of the active lava dome.

Geophysical Research Letters↗

USGS1991

Mass sediment failure and transport features revealed by acoustic techniques, Beringian Margin, Bering Sea, Alaska

Some of the largest single slide masses, including huge blocks tens of kilometers wide, occur on the rise of the central margin. Sliding of these blocks may have initiated the incision of some of the world's largest submarine canyons. One mass failure, particularly well defined by GLORIA, is 55 km long. This slide and others along the plateau are associated with diapiric-like structures indicative of relatively recent tectonism. -from Authors

Marine Geotechnology↗

USGS2006

Temporal organization of an anuran acoustic community in a Taiwanese subtropical forest

We recorded anuran vocalizations in each of four habitats at Lien Hua Chih Field Station, Taiwan, between July 2000 and July 2001. For each 27 biweekly sample, eight recorders taped calls for 1 min out of every 11 between the hours of 17:00 and 07:00. We obtained 11 481 recordings with calls, and identified 21 503 frogs or groups of frogs. These included 20 species, with an average of 10.4??3.5 species calling each night. Some species called year round, others called in the spring and summer, and a third group called only in the fall and winter. The number of species calling and the maximum calling intensity were correlated with both rainfall and air temperature. The nightly pattern of calling varied among species. Most species called continuously throughout the night, whereas some had a peak right after dusk. A few species had different nightly calling patterns in different habitats. Both Rana limnocharis and Rana kuhlii changed their calling pattern in the presence of large choruses of other anuran species. ?? 2006 The Authors.

Journal of Zoology↗

USGS2021

Behavioural response of sea lamprey (Petromyzon marinus) to acoustic stimuli in a small stream

Sea lamprey ( Petromyzon marinus ) are invasive in the Laurentian Great Lakes and parasitically feed on valued fishes. Migration barriers and selective pesticides are used to control sea lamprey, but there is a desire to develop additional control tools such as traps with nonphysical deterrents. Sound has been used as a deterrent for other invasive species, but its potential for manipulating sea lamprey behavior in natural stream conditions remains untested. Here, behavioral responses of upstream-migrating adult sea lamprey in response to low frequency sounds of 70 or 90 Hz was tracked in a small stream (8 m wide) using passive integrated transponder (PIT) telemetry. The low frequency sounds shifted sea lamprey distribution, with up to 30% more sea lamprey detected on PIT antennas without sound compared with PIT antennas with sound playing. Future studies could continue testing low frequency sounds in larger rivers with larger speakers for use as a natural deterrent at sea lamprey barriers to push sea lamprey toward traps.

Canadian Journal of Fisheries and Aquatic Sciences↗

USGS2014

Use of oviduct-inserted acoustic transmitters and positional telemetry to estimate timing and location of spawning: a feasibility study in lake trout, Salvelinus namaycush

Background Oviduct-inserted transmitters have shown promise for determining precise location of spawning in fishes. Use of traditional manual tracking to locate expelled oviduct transmitters is laborious and accurate estimates of time of transmitter expulsion require frequent surveys. We tested the feasibility of using oviduct-inserted transmitters with positional telemetry to estimate time and location of spawning in lake trout (Salvelinus namaycush). Three assumptions were tested: (1) oviduct transmitters remain within fish until spawning, (2) oviduct transmitters are expelled with the eggs during spawning, and (3) time and location of oviduct transmitter expulsion can be accurately determined. Results In the laboratory, 39 of 44 (89%) lake trout retained an oviduct transmitter until end of the spawning period and all premature transmitter expulsions occurred before maturation. Natural spawning in the laboratory was not feasible; however, of 35 ripe trout that retained transmitters, 31 (89%) expelled their transmitter with eggs when subjected to manual stripping. Ability to position transmitters with a telemetry array at known spawning sites in Lake Huron (North America) was poor when oviduct transmitters were placed in the substrate compared to transmitters suspended 1 m above substrate - 78% of transmitters in substrate could not be positioned. However, in simulations, time and location of spawning were determined with reasonable accuracy by double-tagging trout with one transmitter that is expelled with the eggs during spawning while another transmitter remains in the fish. Accuracy of estimated time and location of transmitter spatial separation varied with distance traveled from spawning site and swimming speed, and was dependent on transmission delay. Conclusions Our results satisfied the three assumptions of oviduct tagging and suggested that oviduct transmitters can be used with positional telemetry to estimate time and location of spawning in lake trout and other species. In situations where oviduct transmitters may be difficult to position once expelled into substrate, pairing oviduct transmitters with a normal-sized fish transmitter that remains in the fish is recommended, with spawning inferred when the two tags separate in space. Optimal transmitter delay will depend on expected degree of spawning site residency and swim speed.

Lake Huron↗

USGS2023

Remote characterization of the 12 January 2020 eruption of Taal Volcano, Philippines, using seismo-acoustic, volcanic lightning, and satellite observations

On 12 January 2020, an eruption began on the shores of the Main Crater Lake (MCL) of Taal Volcano—a caldera system on the southern end of Luzon Island in the Philippines. Taal, one of the most active volcanoes in the Philippines, is located 30 km south of Manila—a major metropolitan area with a population of 13.5 million people. Eruptive activity intensified throughout the day on 12 January, producing prolific volcanic lightning, ashfall, and a sustained plume that reached 16–17 km altitude. The chronology of events was well documented by the Philippine Institute of Volcanology and Seismology and the Tokyo Volcanic Ash Advisory Center. The wealth of data collected during the eruption provides a unique opportunity to investigate how the combination of different remote sensing methods may complement local observations and monitoring. Remote systems tend to provide lower resolution data but are also less likely to be compromised by the eruptive activity, thus providing continuous records of eruptive processes. Here, we present a postevent analysis of the 12 January activity, including data from long‐range lightning, infrasound, and seismic arrays located at distances up to several thousands of kilometers from the volcano. By combining these datasets, we distinguish five phases of activity and infer a major shift in eruption behavior around 12:00 on 12 January (UTC). The remote observations suggest that the most of the water within the MCL ( ⁠∼42 million m 3⁠ ) was vaporized and incorporated into the volcanic plume within the first 12 hr of the eruption.

Taal Volcano↗

USGS1972