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Results for “The Seismic Record”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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At least 307 records · Page 17Linked to original sources

USGS1970

Missile impacts as sources of seismic energy on the moon

Seismic signals recorded from impacts of missiles at the White Sands Missile Range are radically different from the signal recorded from the Apollo 12 lunar module impact. This implies that lunar structure to depths of at least 10 to 20 kilometers is quite different from the typical structure of the earth's crust. Results obtained from this study can be used to predict seismic wave amplitudes from future man-made lunar impacts. Seismic energy and crater dimensions from impacts are compared with measurements from chemical explosions.

New Mexico↗

USGS2022

Seismometer records of ground tilt induced by debris flows

A change in surface loading causes the Earth’s surface to deform. Mass movements, such as debris flows, can cause a tilt large enough to be recorded by nearby instruments, but the signal is strongly dependent on the mass loading and subsurface parameters. Specifically designed sensors for such measurements (tiltmeters) are cumbersome to install. Alternatively, broadband seismometers record translational motion and also tilt signals, often at periods of tens to hundreds of seconds. Their horizontal components are thereby the most sensitive to tilt. In this study, we show how to obtain tilt caused by the passing by of debris flows from seismic measurements recorded within tens of meters of the flow and investigate the usefulness of this signal for flow characterization. We investigate the problem on three scales (1) large‐scale laboratory experiments at the U.S. Geological Survey debris‐flow flume, where broadband seismometers and tiltmeters were installed for six 8 – 10    m 3 "> 8 – 10 m 3 experiments, (2) the Illgraben torrent in Switzerland, one of the most active mass wasting sites in the European Alps, where a broadband seismometer placed within a few meters of the channel recorded 15 debris‐flow events with volumes up to 10 5    m 3 "> 10 5 m 3 ⁠ , and (3) Volcán de Fuego, Guatemala, where a broadband seismometer recorded two lahars. We investigate how the tilt signals compare to debris‐flow parameters such as mean normal stresses, usually measured by expensive force plates, and debris‐flow height. We model the elastic ground deformation as the response of an elastic half‐space to a moving surface load. In addition, we use the model with some simplifications to determine the maximum debris‐flow heights of Volcán de Fuego events, where no force plate measurements are available. Finally, we address how and under what assumptions the relatively affordable and straightforward tilt measurements may be utilized to infer debris‐flow parameters, as opposed to force plates and other complicated instrument setups.

Oregon↗

USGS2021

S2HM must be real-time or not?

Seismic structural health monitoring (S 2 HM) has advanced significantly in the last three decades. However, currently there is no consensus on the need for real-time processing of data acquired during an earthquake. Numerous applications exist whereby S 2 HM-equipped systems record valuable seismic response data. A delayed use of the seismic data prohibits timely discovery of hidden damages in a structure which, in turn, possibly increases its vulnerability during events to follow – with increased risk to occupants. Such risks are of particular concern when, for example, there are long-distance/long period effects e.g. for tall buildings and long-span bridges that are significantly affected by events that originate at far distances. These phenomena necessitate near real-time monitored data to make timely data-based informed decisions on the health or performance of the affected structure. The paper discusses criteria for functionality and occupiability thresholds in actual applications.

Conference Paper↗

USGS2020

A brief introduction to seismic instrumentation: Where does my data come from?

Modern seismology has been able to take advantage of several technological advances. These include feedback loops in the seismometer, specialized digitizers with absolute timing, and compression formats for storing data. While all of these advances have helped to improve the field, they can also leave newcomers a bit confused. Our goal here is to give a brief overview of how recordings of seismic ground motion originate. We discuss the chain of events that are required to obtain digital data plus how these steps can be reversed to recover units of ground motion such as acceleration, velocity, or displacement. Finally, we show a few examples of data that has become compromised because of various non-ground motion signals. We hope to give a quick practical introduction to allow the reader to become familiar with the various jargon used in observational seismology.

Seismological Research Letters↗

USGS1982

Distribution of gas-charged sediment in Norton Sound and Chirikov Basin.

Numerous zone of anomalous acoustic resonses caused by gas in the subsurface sediment layers have been detected on seismic reflection records from Norton Sound and Chirikov Basin. The frequency and distribution of these zones suggest that as much as 7000km2 of the northeastern Bering Sea may be underlain by gas-charged sediment. Much of the gas is of shallow biogenic origin, having been generated in buried peat deposits. Seismic velocity beneath a large gas seep south of Nome decreases in the interval from 250 to 440m below the seafloor, where thermogenic gases of deeper origin are migrating upward along a system of basin margin faults.-from Authors

Geologie en Mijnbouw↗

USGS2001

Ocean Drilling Program Leg 178 (Antarctic Peninsula): Sedimentology of glacially influenced continental margin topsets and foresets

Ocean Drilling Program Leg 178 (February-April 1998) drilled two sites (Sites 1097 and 1103) on the outer Antarctic Peninsula Pacific continental shelf. Recovered strata are no older than late Miocene or early Pliocene (<4.6 Ma). Recovery at shallow depths in loosely consolidated and iceberg-turbated bouldery sediment was poor but improved with increasing depth and consolidation to allow description of lithofacies and biofacies and interpretation of depositional environment. Site 1097 lies on the outer shelf within Marguerite Trough which is a major outlet for ice expanding seaward from the Antarctic Peninsula and reached a maximum depth drilled of 436.6 m below the sea floor (mbsf). Seismic stratigraphic data show flat-lying upper strata resting on strata that dip gently seaward. Uppermost strata, to a depth of 150 mbsf, were poorly recovered, but data suggest they consist of diamictites containing reworked and abraded marine microfauna. This interval is interpreted as having been deposited largely as till produced by subglacial cannibalization of marine sediments (deformation till) recording ice sheet expansion across the shelf. Underlying gently dipping strata show massive, stratified and graded diamictite facies with common bioturbation and slump stuctures that are interbedded with laminated and massive mudstones with dropstones. The succession contains a well-preserved in situ marine microfauna typical of open marine and proglacial marine environments. The lower gently dipping succession at Site 1097 is interpreted as a complex of sediment gravity flows formed of poorly sorted glacial debris. Site 1103 was drilled in that part of the continental margin that shows uppermost flat-lying continental shelf topsets overlying steeper dipping slope foresets seaward of a structural mid-shelf high. Drilling reached a depth of 363 mbsf with good recovery in steeply dipping continental slope foreset strata. Foreset strata are dominated by massive and chaotically stratified diamictites interbedded with massive and graded sandstones and mudstones. The sedimentary record and seismic stratigraphy is consistent with deposition on a continental slope from debris flows and turbidity currents released from a glacial source. Data from Sites 1097 and 1103 suggest the importance of aggradation of the Antarctic Peninsula continental shelf by tilt deposition and progradation of the slope by mass flow. This may provide a model for the interpretation of Palaeozoic and Proterozoic glacial successions that accumulated on glacially influenced continental margins.

Marine Geology↗

USGS1972

Earthquakes in the oil field at Rangely, Colorado

Seven years of seismic data recorded at the Uinta Basin Observatory were searched for earthquakes originating near an oil field at Rangely, Colorado, located 65 km ESE of the observatory. Changes in the number of earthquakes recorded per year appear to correlate with changes in the quantity of fluid injected per year. Between November 1962 and January 1970, 976 earthquakes were detected near the oil field by the UBO station; 320 earthquakes were larger than magnitude 1. Richter magnitudes are estimated from both S-wave and P-wave measurements and a method based on the duration of the seismic signal is used to estimate the magnitude of the larger shocks. The two largest shocks had magnitudes of 3.4 and 3.3. The total seismic energy released was l0 l7 ergs. During this same period the energy used for water injection, measured at the wellhead, was 10 21 ergs.

Colorado↗

USGS2018

Coseismic sackungen in the New Madrid seismic zone, USA

High‐resolution lidar reveals newly recognized evidence of strong shaking in the New Madrid seismic zone in the central United States. We mapped concentrations of sackungen (ridgetop spreading features) on bluffs along the eastern Mississippi River valley in northwestern Tennessee that likely form or are reactivated during large earthquakes. These sackungen are concentrated on the hanging wall of the Reelfoot reverse fault and show a preferential orientation indicating ground failure normal to fault strike. These observations suggest that the sackungen record one or more earthquakes on the southern Reelfoot fault since the deposition of the ~30‐ to 11‐ka Peoria Loess and potentially constrain the minimum intensity of near‐fault ground motion. This study demonstrates that sackungen can be used to infer fault source and mechanism and, in combination with field‐based techniques, improve paleoseismic records and seismic hazard models.

New Madrid Seismic Zone↗

USGS1968

Seismic evidence for the thickness of Cenozoic deposits in Mono Basin, California

From gravity and limited seismic data obtained in 1957, Pakiser and others (1960) reported a thickness of Cenozoic deposits in the deepest part of Mono Basin, California, of 5.5 ± 1.5 km. Later, in 1962, from a series of chemical explosions in the westernmost part of Mono Basin and outside the limits of the main depressed structure, the thickness of Cenozoic deposits was estimated to be 1.6 km. In 1966, a series of ten 1-ton chemical explosions was detonated in Mono Lake near the deepest part of the Mono Basin structure for the purpose of studying the relative effectiveness of different types of explosives in generating seismic energy. Seismic waves recorded at distances 25.0 to 92.3 km from the explosions were delayed by 1.43 seconds (referred to a shot on bedrock) as they descended through the low-velocity Cenozoic deposits of Mono Basin. By using the velocities of Cenozoic deposits as determined during the 1957 field season, the thickness of Cenozoic deposits required to account for the 1.43-second delay determined in 1966 has been estimated to be about 5 ± 1 km. The delay of seismic waves emerging in Long Valley was less than expected, indicating that they were propagated into Long Valley mainly through high-velocity rocks. From the rate of deposition of Cenozoic rocks in Mono Basin based on the age and depth of burial of the Bishop Tuff, it was estimated that Mono Basin began to subside in early or middle Pliocene time.

California↗

USGS2009

Seismic reflection characteristics of naturally-induced subsidence affecting transportation

High-resolution seismic reflections have been used effectively to investigate sinkholes formed from the dissolution of a bedded salt unit found throughout most of Central Kansas. Surface subsidence can have devastating effects on transportation structures. Roads, rails, bridges, and pipelines can even be dramatically affected by minor ground instability. Areas susceptible to surface subsidence can put public safety at risk. Subsurface expressions significantly larger than surface depressions are consistently observed on seismic images recorded over sinkholes in Kansas. Until subsidence reaches the ground surface, failure appears to be controlled by compressional forces evidenced by faults with reverse orientation. Once a surface depression forms or dissolution of the salt slows or stops, subsidence structures are consistent with a tensional stress environment with prevalent normal faults. Detecting areas of rapid subsidence potential, prior to surface failure, is the ultimate goal of any geotechnical survey where the ground surface is susceptible to settling. Seismic reflection images have helped correlate active subsidence to dormant paleofeatures, project horizontal growth of active sinkholes based on subsurface structures, and appraise the risk of catastrophic failure. ?? China University of Geosciences (Wuhan) and Springer-Verlag GmbH 2009.

Conference Paper↗

USGS2012

Note: Rotaphone, a new self-calibrated six-degree-of-freedom seismic sensor

We have developed and tested (calibration, linearity, and cross-axis errors) a new six-degree-of-freedom mechanical seismic sensor for collocated measurements of three translational and three rotational ground motion velocity components. The device consists of standard geophones arranged in parallel pairs to detect spatial gradients. The instrument operates in a high-frequency range (above the natural frequency of the geophones, 4.5 Hz). Its theoretical sensitivity limit in this range is 10(-9) m/s in ground velocity and 10(-9) rad/s in rotation rate. Small size and weight, and easy installation and maintenance make the instrument useful for local-earthquake recording and seismic prospecting.

Review of Scientific Instruments↗

USGS2018

Development of a geodetic component for the U.S. West Coast Earthquake Early Warning System

An earthquake early warning (EEW) system, ShakeAlert, is under development for the West Coast of the United States. This system currently uses the first few seconds of waveforms recorded by seismic instrumentation to rapidly characterize earthquake magnitude, location, and origin time; ShakeAlert recently added a seismic line source algorithm. For large to great earthquakes, magnitudes estimated from the earliest seismic data alone generally saturate. Real‐time Global Navigation Satellite System (GNSS) data can directly measure large displacements, enabling accurate magnitude estimates for M w 7 + "> M w 7 + events, possibly before rupture termination. GNSS‐measured displacements also track evolving slip and, alone or in combination with seismic data, constrain finite‐fault models. Particularly for large‐magnitude, long‐rupture events, GNSS‐based magnitude and rupture extent estimates can improve updates to predicted shaking and thus alert accuracy. GNSS data processing centers at ShakeAlert partner institutions provide real‐time streams to the EEW system, and three geodetic EEW algorithms have been developed through the ShakeAlert collaboration. These algorithms will undergo initial testing within ShakeAlert’s computational architecture using a suite of input data that includes simulated real‐time displacements from synthetic earthquakes and GNSS recordings from recent earthquakes worldwide. Performance will be evaluated using metrics and standards consistent with those adopted for ShakeAlert overall. This initial assessment will guide method refinement and synthesis of the most successful features into a candidate geodetic algorithm for the ShakeAlert production system. In parallel, improvements to geodetic networks and streamlining approaches to data processing and exchange will ensure robust geodetic data availability in the event of an earthquake.

West coast↗

USGS2023

Back-azimuth estimation of air-to-ground coupled infrasound from transverse coherence minimization

We present the transverse coherence minimization method (TCM)—an approach to estimate the back-azimuth of infrasound signals that are recorded on an infrasound microphone and a colocated three-component seismometer. Accurate back-azimuth information is important for a variety of monitoring efforts, but it is currently only available for infrasound arrays and for seismoacoustic sensor pairs separated by 10 s of meters. Our TCM method allows for the analysis of colocated sensor pairs, sensors located within a few meters of each other, which may extend the capabilities of existing seismoacoustic networks and supplement operating infrasound arrays. This approach minimizes the coherence of the transverse component of seismic displacement with the infrasound wave to estimate the infrasound back-azimuth. After developing an analytical model, we investigate seismoacoustic signals from the August 2012 Humming Roadrunner experiment and the 26 May 2021 eruption of Great Sitkin Volcano, Alaska, U.S.A., at the ranges of 6.5–185 km from the source. We discuss back-azimuth estimates and potential sources of deviation (1°–15°), such as local terrain effects or deviation from common analytical models. This practical method complements existing seismoacoustic tools and may be suitable for routine application to signals of interest.

The Seismic Record↗

USGS1964

A preliminary summary of a seismic-refraction survey in the vicinity of the Tonto Forest Observatory, Arizona

The U.S. Geological Survey complete d a seismic-refraction survey in the vicinity of the Tonto Forest Seismological Observatory (T.F.S.O.) in April and May 1964. More than 1200 km of reversed profiles were surveyed to determine the crustal structure and crustal and upper mantle velocities in this area. The purpose of this work was to provide information on wave-propagation paths of seismic events recorded at T.F.S.O. and to improve the performance of the Observatory in locating and identifying these events. First arrivals indicate that the Mohorovicic discontinuity dips to the northeast by as much as 6 degrees under T.F.S.O., and may even be displaced vertically by as much as 5 km immediately north of the Observatory near the boundary of the Basin and Range and the Colorado Plateau Provinces. A preliminary examination of the first arrivals indicates that the crust at T.F.S.O. is at least 30 km thick and is made up of at least two seismic layers. A thin veneer at the surface with a velocity of approximately 4 km/sec is underlain by a layer with a velocity of approximately 5.9 km/sec to 6.1 km/sec. An intermediate layer with velocity of 6.6 to 7.0 km/sec is probably present in the lower crust, but is not revealed by first arrivals. The velocity of seismic waves in the upper mantle is about 7.9 km/sec.

Arizona↗

USGS2012

Casual instrument corrections for short-period and broadband seismometers

Of all the filters applied to recordings of seismic waves, which include source, path, and site effects, the one we know most precisely is the instrument filter. Therefore, it behooves seismologists to accurately remove the effect of the instrument from raw seismograms. Applying instrument corrections allows analysis of the seismogram in terms of physical units (e.g., displacement or particle velocity of the Earth’s surface) instead of the output of the instrument (e.g., digital counts). The instrument correction can be considered the most fundamental processing step in seismology since it relates the raw data to an observable quantity of interest to seismologists. Complicating matters is the fact that, in practice, the term “instrument correction” refers to more than simply the seismometer. The instrument correction compensates for the complete recording system including the seismometer, telemetry, digitizer, and any anti‐alias filters. Knowledge of all these components is necessary to perform an accurate instrument correction. The subject of instrument corrections has been covered extensively in the literature (Seidl, 1980; Scherbaum, 1996). However, the prospect of applying instrument corrections still evokes angst among many seismologists—the authors of this paper included. There may be several reasons for this. For instance, the seminal paper by Seidl (1980) exists in a journal that is not currently available in electronic format and cannot be accessed online. Also, a standard method for applying instrument corrections involves the programs TRANSFER and EVALRESP in the Seismic Analysis Code (SAC) package (Goldstein et al. , 2003). The exact mathematical methods implemented in these codes are not thoroughly described in the documentation accompanying SAC.

Seismological Research Letters↗

USGS1978

High resolution seismic profiles, side scan sonar records, and sampling locations from lower Cook Inlet and Kodiak Shelf, R/V SEA SOUNDER cruise S7-77-WG, September - October, 1977

During the period from September 14 through October 10, 1977 the second U.S. Geological Survey geo-environmental cruise was conducted in lower Cook Inlet and on the Kodiak shelf and adjacent upper continental slope, Gulf of Alaska, aboard the R/V SEA SOUNDER (Figure 1, Tables 1, 2 and 3). The objective of this cruise was to study in detail specific potentially hazardous environmental conditions identified as a result of the first reconnaissance geo-environmental cruise conducted from June 18 through July 30, 1976 (Bouma and Hampton, 1976; Hampton and Bouma, 1976). In particular, the distribution and movement of seafloor bedforms were studied in lower Cook Inlet, and sediment dispersal patterns and submarine sediment slides were investigated on the Kodiak shelf and slope. High resolution seismic profiling (sparker, uniboom, minisparker, 3.5 khz, 12 khz) and side-scanning sonar surveys formed the basis for selecting stations for observations with bottom television and 70 mm bottom camera as well as for different types of sampling of surficial sediments (piston corer, gravity corer, hydroplastic corer, Soutar grab sampler). The success of the 1977 cruise was limited by adverse weather conditions.

Alaska↗

USGS2026

Measuring stress In high pressure deformation experiments with high speed fiber-optics

High‐pressure, high‐temperature rock deformation experiments are essential for understanding deep Earth processes, but accurately measuring stress is challenging due to the inaccuracy introduced by seal friction within the apparatus and large inertia, which affects earthquake process measurements made far from the experimental fault. To overcome these limitations, we developed and implemented a simple, compact fiber‐optic sensor based on an External Cavity Fabry–Perot Interferometer for in situ load measurement on a piston inside the pressure vessel of a Griggs‐type high‐pressure apparatus. The sensor can be used at sample temperatures up to 800°C for both slow creep and fast rupture testing with bandwidth capability from DC to 6 MHz. Two important experimental results are described: (1) the first direct measurements of seal friction in this apparatus type; these measurements record seal friction approximately one‐tenth of the confining pressure under both low (150 MPa) and high (1 GPa) pressure conditions; and (2) high‐temporal resolution capture of dynamic stress drops during stick‐slip faulting events at high‐confining pressure, revealing near‐fault wave propagation details, high‐frequency oscillations, and implying high‐transient slip rates (6–12 m/s) previously inaccessible with external sensors.

The Seismic Record↗

USGS1996

National energy research seismic library; Powder River basin, Montana-Wyoming; surface reflection and vertical seismic profile data used in seismic-stratigraphic investigations for ground-water aquifers and hydrocarbon traps

This Digital Data Series publication contains both raw and processed seismic data recorded during the period 1975 through 1978 by several geophysical service companies under contract to the USGS in the following study areas of the Powder River Basin, Montana and Wyoming: 1. Powder River and Custer Counties, MT (T. 1 S., T. 1-2 N., R. 53-54 E.) 2. Carter County, MT (T. 57-58 N., R. 65 W.) and Crook County, WY (T. 9 S., R.57-58 E.) 3. Powder River and Carter Counties, MT (T. 8 S., R. 53-55 E.) 4. Niobrara County, WY (T. 36-38 N., R. 61-62 W.) and Weston County, WY (T. 45 N., R. 61 W.) Four multichannel Vibroseis seismic lines, six Vertical Seismic Profiles (VSP's), and associated support material (observer's notes, X-Y coordinates, elevations of source and receivers, for example) are included. The raw (unprocessed) field data and a processed version of each surface profile and VSP are contained in standard SEG-Y format files; support material are in ASCII format text files. The processed surface data are versions which were reprocessed by the USGS in 1995 using state-of-the-art seismic data processing software.

Data Series↗