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At least 901 records · Page 50Linked to original sources
USGS2026

Evaluating U.S. Geological Survey 3D Elevation Program LiDAR data as a source for building height

Accurate building height information is used for numerous urban applications, including infrastructure modeling, disaster risk assessment, and energy demand estimation. The U.S. Geological Survey collects airborne lidar data to support the three-dimensional elevation program (3DEP). The high point density and vertical accuracy of the lidar point clouds are optimal for 3D mapping. Few studies have systematically evaluated building height extraction from 3DEP lidar point clouds in urban areas. This study assesses the accuracy and consistency of building height estimates from two publicly available data sets by comparing them to the 3DEP lidar data. The public building height data sets are USA Structures and Microsoft Global Building Footprints (GBF), and they are evaluated across two contrasting urban sites. Building heights from USA Structures are also lidar-derived, whereas GBF estimates are based on stereo matching of optical imagery. Building heights from 3DEP were extracted by classifying lidar points using a deep learning model, isolating roof and ground returns, and computing the height as the median elevation difference between the roof and surrounding ground points. For both sites, 3DEP lidar-derived heights show strong agreement with USA Structures (R 2 = 0.87 and 0.86; MAE = 1.8 and 2.2 m), confirming the internal consistency and reliability of lidar-derived measurements. In contrast, comparisons with GBF height estimates reveal significantly lower correlations (R 2 = 0.54 and 0.60; MAE = 2.5 and 3.1 m), highlighting the limitations of imagery-based height reconstruction, particularly in dense or heterogeneous urban environments. These findings indicate that lidar can be used as an accurate source for vertical structure characterization and underscore the benefits of improved integration and bias correction when using imagery-derived building heights. The results provide support for hybrid approaches that combine the broad spatial coverage of optical data sets with the accuracy of lidar for scalable 3D urban mapping.

Colorado, Texas↗
USGS1996

Ground-Water Discharge to Biscayne Bay

Introduction The South Florida Ecosystem Restoration Program is an intergovernmental effort, involving a number of agencies, to reestablish and maintain the ecosystem of south Florida. One element of the restoration effort is the development of a firm scientific basis for resource decision making. The U.S. Geological Survey (USGS), one of the agencies, provides scientific information as part of the South Florida Ecosystem Restoration Program. The USGS began their own program, called the South Florida Ecosystem Program, in fiscal year 1995 for the purpose of gathering hydrologic, cartographic, and geologic data that relate to the mainland of south Florida, Florida Bay, and the Florida Keys and Reef ecosystems. Over the years, the construction of canals and levees has altered the natural hydrologic conditions of the Everglades. The canals and levees were constructed to convey water, prevent flooding, and store water in conservation areas for future use. The U.S. Army Corps of Engineers (COE) in Jacksonville, Fla., is planning to construct gated spillways and culverts to allow for the restoration of natural sheetflow conditions to Everglades National Park (ENP). These proposed changes may further affect the hydrologic conditions of ENP and other parts of the ecosystem, thus leading to the following questions: Is ground water flowing to Biscayne Bay a significant component of the water budget in south Florida? Would the quantity of ground water flowing to Biscayne Bay be greatly affected by changes in the operation of gates and control structures in canals? How much change in ground-water discharges to Biscayne Bay has occurred due to modifications to the hydrologic system? Federal, State, and local agencies need to know the effect that changes in the operation of gates and control structures in canals will have on the water-budget components of the natural water systems in south Florida, including ground-water flow to Biscayne Bay.

Florida↗
USGS1989

A close-range photogrammetric technique for mapping neotectonic features in trenches

Close-range photogrammetric techniques and newly available computerized plotting equipment were used to map exploratory trench walls that expose Quaternary faults in the vicinity of Yucca Mountain, Nevada. Small-scale structural, lithologic, and stratigraphic features can be rapidly mapped by the photogrammetric method. This method is more accurate and significantly more rapid than conventional trench-mapping methods, and the analytical plotter is capable of producing cartographic definition of high resolution when detailed trench maps are necessary.

Bulletin of the Association of Engineering Geologi↗
USGS2013

National assessment of geologic carbon dioxide storage resources: Results

In 2012, the U.S. Geological Survey (USGS) completed an assessment of the technically accessible storage resources ( TA SR ) for carbon dioxide (CO 2 ) in geologic formations underlying the onshore and State waters area of the United States. The formations assessed are at least 3,000 feet (914 meters) below the ground surface. The TA SR is an estimate of the CO 2 storage resource that may be available for CO 2 injection and storage that is based on present-day geologic and hydrologic knowledge of the subsurface and current engineering practices. Individual storage assessment units (SAUs) for 36 basins were defined on the basis of geologic and hydrologic characteristics outlined in the assessment methodology of Brennan and others (2010, USGS Open-File Report 2010–1127) and the subsequent methodology modification and implementation documentation of Blondes, Brennan, and others (2013, USGS Open-File Report 2013–1055). The mean national TA SR is approximately 3,000 metric gigatons (Gt). The estimate of the TA SR includes buoyant trapping storage resources ( B SR ), where CO 2 can be trapped in structural or stratigraphic closures, and residual trapping storage resources, where CO 2 can be held in place by capillary pore pressures in areas outside of buoyant traps. The mean total national B SR is 44 Gt. The residual storage resource consists of three injectivity classes based on reservoir permeability: residual trapping class 1 storage resource ( R1 SR ) represents storage in rocks with permeability greater than 1 darcy (D); residual trapping class 2 storage resource ( R2 SR ) represents storage in rocks with moderate permeability, defined as permeability between 1 millidarcy (mD) and 1 D; and residual trapping class 3 storage resource ( R3 SR ) represents storage in rocks with low permeability, defined as permeability less than 1 mD. The mean national storage resources for rocks in residual trapping classes 1, 2, and 3 are 140 Gt, 2,700 Gt, and 130 Gt, respectively. The known recovery replacement storage resource ( KRR SR ) is a conservative estimate that represents only the amount of CO 2 at subsurface conditions that could replace the volume of known hydrocarbon production. The mean national KRR SR , determined from production volumes rather than the geologic model of buoyant and residual traps that make up TA SR , is 13 Gt. The estimated storage resources are dominated by residual trapping class 2, which accounts for 89 percent of the total resources. The Coastal Plains Region of the United States contains the largest storage resource of any region. Within the Coastal Plains Region, the resources from the U.S. Gulf Coast area represent 59 percent of the national CO 2 storage capacity.

Circular↗
USGS2004

Summary and Comparison of Multiphase Streambed Scour Analysis at Selected Bridge Sites in Alaska

The U.S. Geological Survey and the Alaska Department of Transportation and Public Facilities undertook a cooperative multiphase study of streambed scour at selected bridges in Alaska beginning in 1994. Of the 325 bridges analyzed for susceptibility to scour in the preliminary phase, 54 bridges were selected for a more intensive analysis that included site investigations. Cross-section geometry and hydraulic properties for each site in this study were determined from field surveys and bridge plans. Water-surface profiles were calculated for the 100- and 500-year floods using the Hydrologic Engineering Center?s River Analysis System and scour depths were calculated using methods recommended by the Federal Highway Administration. Computed contraction-scour depths for the 100- and 500-year recurrence-interval discharges exceeded 5 feet at six bridges, and pier-scour depths exceeded 10 feet at 24 bridges. Complex pier-scour computations were made at 10 locations where the computed contraction-scour depths would expose pier footings. Pressure scour was evaluated at three bridges where the modeled flood water-surface elevations intersected the bridge structure. Site investigation at the 54 scour-critical bridges was used to evaluate the effectiveness of the preliminary scour analysis. Values for channel-flow angle of attack and approach-channel width were estimated from bridge survey plans for the preliminary study and were measured during a site investigation for this study. These two variables account for changes in scour depths between the preliminary analysis and subsequent reanalysis for most sites. Site investigation is needed for best estimates of scour at bridges with survey plans that indicate a channel-flow angle of attack and for locations where survey plans did not include sufficient channel geometry upstream of the bridge.

Scientific Investigations Report↗
USGS2017

Implementing Nepal's national building code—A case study in patience and persistence

The April 2015 Gorkha Nepal earthquake revealed the relative effectiveness of the Nepal Standard, or national building code (NBC), and irregular compliance with it in different parts of Nepal. Much of the damage to more than half a million Nepal's residential structures may be attributed to the prevalence of owner-built or owner-supervised construction and the lack of owner and builder responsiveness to seismic risk and training in the appropriate means of complying with the NBC. To explain these circumstances, we review the protracted implementation of the NBC and the role played by one organization, the National Society for Earthquake Technology-Nepal (NSET), in the NBC's implementation. We also share observations on building code compliance made by individuals in Nepal participating in workshops led by the Earthquake Engineering Research Institute's 2014 class of Housner Fellows.

Earthquake Spectra↗
USGS2014

Estimating structural collapse fragility of generic building typologies using expert judgment

The structured expert elicitation process proposed by Cooke (1991), hereafter referred to as Cooke’s approach, is applied for the first time in the realm of structural collapse-fragility assessment for selected generic construction types. Cooke’s approach works on the principle of objective calibration scoring of judgments coupled with hypothesis testing used in classical statistics. The performance-based scoring system reflects the combined measure of an expert’s informativeness about variables in the problem area under consideration, and their ability to enumerate, in a statistically accurate way through expressing their true beliefs, the quantitative uncertainties associated with their assessments. We summarize the findings of an expert elicitation workshop in which a dozen earthquake-engineering professionals from around the world were engaged to estimate seismic collapse fragility for generic construction types. Development of seismic collapse fragility functions was accomplished by combining their judgments using weights derived from Cooke’s method. Although substantial effort was needed to elicit the inputs of these experts successfully, we anticipate that the elicitation strategy described here will gain momentum in a wide variety of earthquake seismology and engineering hazard and risk analyses where physical model and data limitations are inherent and objective professional judgment can fill gaps.

Conference Paper↗
USGS2006

Estimated flood-inundation mapping for the Lower Blue River in Kansas City, Missouri, 2003-2005

The U.S. Geological Survey, in cooperation with the city of Kansas City, Missouri, began a study in 2003 of the lower Blue River in Kansas City, Missouri, from Gregory Boulevard to the mouth at the Missouri River to determine the estimated extent of flood inundation in the Blue River valley from flooding on the lower Blue River and from Missouri River backwater. Much of the lower Blue River flood plain is covered by industrial development. Rapid development in the upper end of the watershed has increased the volume of runoff, and thus the discharge of flood events for the Blue River. Modifications to the channel of the Blue River began in late 1983 in response to the need for flood control. By 2004, the channel had been widened and straightened from the mouth to immediately downstream from Blue Parkway to convey a 30-year flood. A two-dimensional depth-averaged flow model was used to simulate flooding within a 2-mile study reach of the Blue River between 63rd Street and Blue Parkway. Hydraulic simulation of the study reach provided information for the design and performance of proposed hydraulic structures and channel improvements and for the production of estimated flood-inundation maps and maps representing an areal distribution of water velocity, both magnitude and direction. Flood profiles of the Blue River were developed between Gregory Boulevard and 63rd Street from stage elevations calculated from high water marks from the flood of May 19, 2004; between 63rd Street and Blue Parkway from two-dimensional hydraulic modeling conducted for this study; and between Blue Parkway and the mouth from an existing one-dimensional hydraulic model by the U.S. Army Corps of Engineers. Twelve inundation maps were produced at 2-foot intervals for Blue Parkway stage elevations from 750 to 772 feet. Each map is associated with National Weather Service flood-peak forecast locations at 63rd Street, Blue Parkway, Stadium Drive, U.S. Highway 40, 12th Street, and the Missouri River at the Hannibal railroad bridge in Kansas City. The National Weather Service issues peak-stage forecasts for these locations during times of flooding. Missouri River backwater inundation profiles were developed using interpolated Missouri River stage elevations at the mouth of the Blue River. Twelve backwater-inundation maps were produced at 2-foot intervals for the mouth of the Blue River from 730.9 to 752.9. To provide public access to the information presented in this report, a World Wide Web site (http://mo.water.usgs.gov/indep/kelly/blueriver/index.htm) was created that displays the results of two-dimensional modeling between 63rd Street and Blue Parkway, estimated flood-inundation maps, estimated backwater-inundation maps, and the latest gage heights and National Weather Service stage forecast for each forecast location within the study area. In addition, the full text of this report, all tables, and all plates are available for download at http://pubs.water.usgs.gov/sir2006-5089.

Missouri↗
USGS2014

Advances in a distributed approach for ocean model data interoperability

An infrastructure for earth science data is emerging across the globe based on common data models and web services. As we evolve from custom file formats and web sites to standards-based web services and tools, data is becoming easier to distribute, find and retrieve, leaving more time for science. We describe recent advances that make it easier for ocean model providers to share their data, and for users to search, access, analyze and visualize ocean data using MATLAB® and Python®. These include a technique for modelers to create aggregated, Climate and Forecast (CF) metadata convention datasets from collections of non-standard Network Common Data Form (NetCDF) output files, the capability to remotely access data from CF-1.6-compliant NetCDF files using the Open Geospatial Consortium (OGC) Sensor Observation Service (SOS), a metadata standard for unstructured grid model output (UGRID), and tools that utilize both CF and UGRID standards to allow interoperable data search, browse and access. We use examples from the U.S. Integrated Ocean Observing System (IOOS®) Coastal and Ocean Modeling Testbed, a project in which modelers using both structured and unstructured grid model output needed to share their results, to compare their results with other models, and to compare models with observed data. The same techniques used here for ocean modeling output can be applied to atmospheric and climate model output, remote sensing data, digital terrain and bathymetric data.

Journal of Marine Science and Engineering↗
USGS1991

Integration of remote sensing and GIS: Data and data access

CT: Theintegration of remote sensing tools and technology with the spatial analysis orientation of geographic information systems is a complex task. In this paper, we focus on the issues of making data available and useful to the user. In part, this involves a set of problems which reflect on the physical and logical structures used to encode the data. At the same time, however, the mechanisms and protocols which provide information about the data, and which maintain the data through time, have become increasingly important. We discuss these latter issues from the viewpoint of the functions which must be provided by archives of spatial data.

Photogrammetric Engineering and Remote Sensing↗
USGS1996

Well-construction, water-level, and water-quality data for ground-water monitoring wells for the J4 hydrogeologic study, Arnold Air Force Base, Tennessee

Between December 1993 and March 1994, 27 wells were installed at 12 sites near the J4 test cell at Arnold Engineering Development Center in Coffee County, Tennessee. The wells ranged from 28 to 289 feet deep and were installed to provide information on subsurface lithology, aquifer characteristics, ground-water levels, and ground-water quality. This information will be used to help understand the effects of dewatering operations at the J4 test cell on the local ground-water-flow system. The J4 test cell, extending approximately 250 feet below land surface, is used in the testing of rocket motors. Ground water must be pumped continuously from around the test cell to keep it structurally intact. The amount of water discharged from the J4 test cell was monitored to estimate the average rate of ground-water withdrawal at the J4 test cell. Ground- water levels were monitored continuously at 14 wells for 12 months. Water-quality samples were collected from 26 of the new wells, 9 existing wells, and the ground-water discharge from the J4 test cell. All samples were analyzed for common inorganic ions, trace metals, and volatile organic compounds.

Tennessee↗
USGS2024

Characterization of the structural–stratigraphic and reservoir controls on the occurrence of gas hydrates in the Eileen Gas Hydrate Trend, Alaska North Slope

One of the most studied permafrost-associated gas hydrate accumulations in Arctic Alaska is the Eileen Gas Hydrate Trend. This study provides a detailed re-examination of the Eileen Gas Hydrate Trend with a focus on the gas hydrate accumulation in the western part of the Prudhoe Bay Unit. This integrated analysis of downhole well log data and published geophysical data has provided new insight on structural, stratigraphic, and reservoir controls on the occurrence of gas hydrates in the Eileen Gas Hydrate Trend. This study revealed the relatively complex nature of the gas hydrate occurrences in the Eileen Gas Hydrate Trend, with gas hydrates present in a series of coarsening upward, laterally pervasive, mostly fine-grained sand beds exhibiting high gas hydrate saturations. Most of the gas hydrate-bearing reservoirs in the Eileen Gas Hydrate Trend are laterally segmented into distinct northwest- to southeast-trending fault blocks, occur in a combination of structural–stratigraphic traps, and are only partially hydrate filled with distinct down-dip water contacts. These findings suggest that the traditional parts of a petroleum system (i.e., reservoir, gas source, gas migration, and geologic timing of the system formation) also control the occurrence of gas hydrates in the Eileen Gas Hydrate Trend.

Alaska↗
USGS2017

Barrier island habitat map and vegetation survey—Dauphin Island, Alabama, 2015

Barrier islands are dynamic environments due to their position at the land-sea interface. Storms, waves, tides, currents, and relative sea-level rise are powerful forces that shape barrier island geomorphology and habitats (for example, beach, dune, marsh, and forest). Hurricane Katrina in 2005 and the Deep Water Horizon oil spill in 2010 are two major events that have affected habitats and natural resources on Dauphin Island, Alabama. The latter event prompted a collaborative effort between the U.S. Geological Survey, the U.S. Army Corps of Engineers, and the State of Alabama funded by the National Fish and Wildlife Foundation to investigate viable, sustainable restoration options that protect and restore the natural resources of Dauphin Island, Alabama. In order to understand the feasibility and sustainability of various restoration scenarios, it is important to understand current conditions on Dauphin Island. To further this understanding, a detailed 19-class habitat map for Dauphin Island was produced from 1-foot aerial infrared photography collected on December 4, 2015, and lidar data collected in January 2015. We also conducted a ground survey of habitat types, vegetation community structure, and elevations in November and December 2015. These products provide baseline data regarding the ecological and general geomorphological attributes of the area, which can be compared with observations from other dates for tracking changes over time.

Alabama↗
USGS2005

X-ray scattering and spectroscopy studies on diesel soot from oxygenated fuel under various engine load conditions

Diesel soot from reference diesel fuel and oxygenated fuel under idle and load engine conditions was investigated with X-ray scattering and X-ray carbon K-edge absorption spectroscopy. Up to five characteristic size ranges were found. Idle soot was generally found to have larger primary particles and aggregates but smaller crystallites, than load soot. Load soot has a higher degree of crystallinity than idle soot. Adding oxygenates to diesel fuel enhanced differences in the characteristics of diesel soot, or even reversed them. Aromaticity of idle soot from oxygenated diesel fuel was significantly larger than from the corresponding load soot. Carbon near-edge X-ray absorption fine structure (NEXAFS) spectroscopy was applied to gather information about the presence of relative amounts of carbon double bonds (CC, CO) and carbon single bonds (C-H, C-OH, COOH). Using scanning X-ray transmission microspectroscopy (STXM), the relative amounts of these carbon bond states were shown to vary spatially over distances approximately 50 to 100 nm. The results from the X-ray techniques are supported by thermo-gravimetry analysis and high-resolution transmission electron microscopy. ?? 2005 Elsevier Ltd. All rights reserved.

Carbon↗
USGS1998

Chapter A. The Loma Prieta, California, Earthquake of October 17, 1989 - Lifelines

To the general public who had their televisions tuned to watch the World Series, the 1989 Loma Prieta earthquake was a lifelines earthquake. It was the images seen around the world of the collapsed Cypress Street viaduct, with the frantic and heroic efforts to pull survivors from the structure that was billowing smoke; the collapsed section of the San Francisco-Oakland Bay Bridge and subsequent home video of a car plunging off the open span; and the spectacular fire in the Marina District of San Francisco fed by a broken gasline. To many of the residents of the San Francisco Bay region, the relation of lifelines to the earthquake was characterized by sitting in the dark because of power outage, the inability to make telephone calls because of network congestion, and the slow and snarled traffic. Had the public been aware of the actions of the engineers and tradespeople working for the utilities and other lifeline organizations on the emergency response and restoration of lifelines, the lifeline characteristics of this earthquake would have been even more significant. Unobserved by the public were the warlike devastation in several electrical-power substations, the 13 miles of gas-distribution lines that had to be replaced in several communities, and the more than 1,200 leaks and breaks in water mains and service connections that had to be excavated and repaired. Like the 1971 San Fernando, Calif., earthquake, which was a seminal event for activity to improve the earthquake performance of lifelines, the 1989 Loma Prieta earthquake demonstrated that the tasks of preparing lifelines in 'earthquake country' were incomplete-indeed, new lessons had to be learned.

Professional Paper↗
USGS2013

GEM Building Taxonomy (Version 2.0)

This report documents the development and applications of the Building Taxonomy for the Global Earthquake Model (GEM). The purpose of the GEM Building Taxonomy is to describe and classify buildings in a uniform manner as a key step towards assessing their seismic risk, Criteria for development of the GEM Building Taxonomy were that the Taxonomy be relevant to seismic performance of different construction types; be comprehensive yet simple; be collapsible; adhere to principles that are familiar to the range of users; and ultimately be extensible to non-buildings and other hazards. The taxonomy was developed in conjunction with other GEM researchers and builds on the knowledge base from other taxonomies, including the EERI and IAEE World Housing Encyclopedia, PAGER-STR, and HAZUS. The taxonomy is organized as a series of expandable tables, which contain information pertaining to various building attributes. Each attribute describes a specific characteristic of an individual building or a class of buildings that could potentially affect their seismic performance. The following 13 attributes have been included in the GEM Building Taxonomy Version 2.0 (v2.0): 1.) direction, 2.)material of the lateral load-resisting system, 3.) lateral load-resisting system, 4.) height, 5.) date of construction of retrofit, 6.) occupancy, 7.) building position within a block, 8.) shape of the building plan, 9.) structural irregularity, 10.) exterior walls, 11.) roof, 12.) floor, 13.) foundation system. The report illustrates the pratical use of the GEM Building Taxonomy by discussing example case studies, in which the building-specific characteristics are mapped directly using GEM taxonomic attributes and the corresponding taxonomic string is constructed for that building, with "/" slash marks separating attributes. For example, for the building shown to the right, the GEM Taxonomy string is: DX 1 /MUR+CLBRS+MOCL 2 /LWAL 3 / DY/MUR+CLBRS+MOCL/LWAL/YPRE:1939 4 /HEX:2 5 /RES 6 / 7 / 8 /IRRE 9 /10/RSH3+RWO2 11 /FW 12 / 13 / which can be read as (1) Direction = [DX or DY] (the building has the same lateral load-resisting system in both directions); (2) Material = [Unreinforced Masonry + solid fired clay bricks + cement: lime mortar]; (3) Lateral Load-Resisting System = [Wall]; (4) Date of construction = [pre-1939]; (5) Heaight = [exactly 2 storeys]; (6) Occupancy = [residential, unknown type]; (7) Building Position = [unknown = no entry]; (8) Shape of building plan = [unknown = no entry]; (9) Structural irregularity = [regular]; (10) Exterior walls = [unknown = no entry]; (11) Roof = [Shape: pitched and hipped, Roof covering: clay tiles, Roof system material: wood, Roof system type: wood trusses]; (12) Floor = [Floor system: Wood, unknown]; (13) Foundation = [unknown = no entry]. Mapping of GEM Building Taxonomy to selected taxonomies is included in the report -- for example, the above building would be referenced by previous structural taxonomies as: PAGER-STR as UFB or UFB4, by the World Housing Encyclopedia as 7 or 8 and by the European Macroseismic Scale (98) as M5. The Building Taxonomy data model is highly flexible and has been incorporated within a relational database architecture. Due to its ability to represent building typologies using a shorthand form, it is also possible to use the taxonomy for non-database applications, and we discuss possible application of adaptation for Building Information Modelling (BIM) systems, and for the insurance industry. The GEM Building Taxonomy was independently evaluated and tested by the Earthquake Engineering Research Institute (EERI), which received 217 TaxT reports from 49 countries, representing a wide range of building typologies, including single and multi-storey buildings, reinforced and unreinforced masonry, confined masonry, concrete, steel, wood, and earthern buildings used for residential, commercial, industrial, and educational occupancy. Based on these submissions and other feedback, the EERI team validated that the GEM Building Taxonomy is highly functional, robust and able to describe different buildings around the world. The GEM Building Taxonomy is accompanied by supplementary resources. All terms have been explained in a companion online Glossary, which provides both text and graphic descriptions. The Taxonomy is accompanied by TaxT, a computer application that enables a user record information about a building or a building typology using the attributes of the GEM Building Taxonomy v2.0. TaxT can generate a taxonomy string and enable a user to generate a report in PDF format which summarizes the attribute values (s)he has chosen as representative of the building typology under consideration. The report concludes with recommendations for future development of the GEM Building Taxonomy. Appendices provide the detailed GEM Building Taxonomy tables and additional resource, as well as mappings to other taxonomies.

GEM Technical Report↗
USGS2008

The role of local soil-induced amplification in the 27 July 1980 northeastern Kentucky earthquake

Amplification of earthquake ground motions by near-surface soil deposits was believed to have occurred in Maysville, Kentucky, U.S.A. during the northeast Kentucky (Sharpsburg) earthquake (mb,Lg 5.3) of July 27, 1980. The city of Maysville, founded on approximately 30 m of Late Quaternary Ohio River flood plain alluvium, was 52 km from the epicenter, but experienced equivalent or higher Modified Mercalli Intensity (MMI) VII, compared with the epicentral area of the earthquake (i.e., MMI VI-VII). In this study, dynamic soil properties were obtained at 10 sites in Maysville using seismic P-wave and S-wave (SH-mode) refraction and reflection methods. Synthetically generated composite time histories and limited geotechnical information, along with the measured dynamic properties, were used to perform one-dimensional linear-equivalent amplification analyses. The results indicated the soils generated ground-motion amplification factors between 3.0 and 6.0 and at a frequency range between 2.0 and 5.0 Hz (0.2 to 0.5 s). The building damage in Maysville from the Sharpsburg earthquake was predominantly found in one- to three-story masonry structures. The estimated fundamental period for one- to three-story masonry buildings is approximately 0.11 to 0.26 s (3.8 to 9 Hz). These correlations suggest the elevated ground motion intensity in Maysville can be accounted for by near-surface soil-amplification effects and resonance of the ground motion by the buildings (i.e., double resonance).

Environmental & Engineering Geoscience↗
USGS2008

Strong motion observations and recordings from the great Wenchuan Earthquake

The National Strong Motion Observation Network System (NSMONS) of China is briefly introduced in this paper. The NSMONS consists of permanent free-field stations, special observation arrays, mobile observatories and a network management system. During the Wenchuan Earthquake, over 1,400 components of acceleration records were obtained from 460 permanent free-field stations and three arrays for topographical effect and structural response observation in the network system from the main shock, and over 20,000 components of acceleration records from strong aftershocks occurred before August 1, 2008 were also obtained by permanent free-field stations of the NSMONS and 59 mobile instruments quickly deployed after the main shock. The strong motion recordings from the main shock and strong aftershocks are summarized in this paper. In the ground motion recordings, there are over 560 components with peak ground acceleration (PGA) over 10 Gal, the largest being 957.7 Gal. The largest PGA recorded during the aftershock exceeds 300 Gal. ?? 2008 Institute of Engineering Mechanics, China Earthquake Administration and Springer-Verlag GmbH.

Earthquake Engineering and Engineering Vibration↗