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At least 109 records · Page 6Linked to original sources
USGS1993

Introduction: Geomorphic studies of the storm and flood of November 3-5, 1985, in the upper Potomac and Cheat River basins

The heavy rains of November 3-5, 1985, produced record floods and extensive landsliding in the Potomac and Cheat River basins in West Virginia and Virginia (pl. 1). Although rainfall intensity was moderate, the storm covered a very large area and produced record floods for basins in the size range of 1000-10,000 km 2 . In addition, thousands of landslides were triggered on slopes underlain by shale bedrock. The total social cost of the storm amounted to 70 lives lost and an estimated $1.3 billion in damage to homes, businesses, roads, and productive land in West Virginia and Virginia (Federal Emergency Management Agency (FEMA) 1985a, b). These extreme costs were incurred despite the fact that the affected area is sparsely populated. To understand the origins and geomorphic effects of the 1985 storm, studies were undertaken by the U.S. Geological Survey, University of Maryland, West Virginia University, Cornell University, University of Virginia, The Johns Hopkins University, and Carleton College. Personnel were also consulted from the National Weather Service, Nuclear Regulatory Commission, U.S. Army Corps of Engineers, Soil Conservation Service, and Interstate Commission on the Potomac River basin. This cooperative effort serves to document the effects of the storm as an example of an extreme geomorphic event in the central Appalachian Mountains. The following chapters comprise observations and preliminary analyses for some of the observed phenomena. Subsequent publications by the contributors to this volume will expand the scope of this research.

Virginia, West Virginia↗
USGS2026

Comparison of data handling techniques for modeling bat acoustic activity

With the proliferation of acoustic sampling to investigate bat distribution and ecology, researchers have implemented a myriad of statistical modeling approaches to interpret findings. Bats are taxa of high conservation concern; therefore, ensuring the accuracy of species-level habitat association models is critical for informing management. We sought to determine prediction differences among statistical approaches to modeling counts of acoustic detections, using generalized linear mixed models with 8 acoustic data-handling techniques. We applied each approach or combination of approaches to a rare species, the northern long-eared bat ( Myotis septentrionalis ), and a common species, the eastern red bat ( Lasiurus borealis ), from summer survey results on a landscape in south-central Pennsylvania, USA, 2024. We evaluated the accuracy of habitat association models of bat acoustic activity at the species level using cross-validation and compared resulting predictions of models using spatial correlations. We determined that filtering data by automated identification software (Kaleidoscope Pro), the maximum likelihood estimate (MLE) P -value thresholds reduced relative mean absolute error (rMAE) in cross-validation of northern long-eared bat models. Using the MLE-retained data produced the most accurate predictions over using raw data or the overly conservative match ratio data. However, for the eastern red bat, the results from the most conservative approach of only retaining data with at least a 90% match ratio from software development training sets had the lowest rMAE. We have provided evidence that the current standard of filtering data by nightly MLE can result in more accurate and informative habitat-use acoustic activity models for rare bat species.

Pennsylvania↗
USGS2021

Case 3853 – Eumeces niger Hombron & Jacquinot, 1853 (currently Emoia nigra) (Reptilia, Scincidae): proposed conservation of prevailing usage by setting aside a lectotype designation for Gongylus (Eumeces) freycineti Duméril & Bibron, 1839 (currently Emoia atrocostata freycineti)

The purpose of the present application, under Articles 74.1.1 and 81.1 of the Code, is to maintain consistent usage of the commonly used name Emoia nigra (Hombron & Jacquinot, 1853 ) by setting aside a lectotype designation for Gongylus ( Eumeces ) freycineti Duméril & Bibron, 1839 by Wells & Wellington in 1985 in favour of a later lectotype designation by Brown in 1991 .

The Bulletin of Zoological Nomenclature↗
USGS2013

Streamflow statistics for unregulated and regulated conditions for selected locations on the Yellowstone, Tongue, and Powder Rivers, Montana, 1928-2002

Major floods in 1996 and 1997 on the Yellowstone River in Montana intensified public debate over the effects of human activities on the Yellowstone River. In 1999, the Yellowstone River Conservation District Council was formed to address conservation issues on the river. The Yellowstone River Conservation District Council partnered with the U.S. Army Corps of Engineers to conduct a cumulative-effects study on the main stem of the Yellowstone River. The cumulative-effects study is intended to provide a basis for future management decisions in the watershed. Streamflow statistics, such as flow-frequency and flow-duration data calculated for unregulated and regulated streamflow conditions, are a necessary component of the cumulative effects study. The U.S. Geological Survey, in cooperation with the Yellowstone River Conservation District Council and the U.S. Army Corps of Engineers, calculated streamflow statistics for unregulated and regulated conditions for the Yellowstone, Tongue, and Powder Rivers for the 1928–2002 study period. Unregulated streamflow represents flow conditions that might have occurred during the 1928–2002 study period if there had been no water-resources development in the Yellowstone River Basin. Regulated streamflow represents estimates of flow conditions during the 1928–2002 study period if the level of water-resources development existing in 2002 was in place during the entire study period. Peak-flow frequency estimates for regulated and unregulated streamflow were developed using methods described in Bulletin 17B. High-flow frequency and low-flow frequency data were developed for regulated and unregulated streamflows from the annual series of highest and lowest (respectively) mean flows for specified n-day consecutive periods within the calendar year. Flow-duration data, and monthly and annual streamflow characteristics, also were calculated for the unregulated and regulated streamflows.

Montana;North Dakota;Wyoming↗
USGS2022

Integrated geochemical approach to determine the source of methane in gas hydrate from Green Canyon Block 955 in the Gulf of Mexico

Massive volumes of gas are sequestered within gas hydrate in subsurface marine sediments in the Gulf of Mexico. Methane associated with gas hydrate is a potentially important economic resource and a significant reservoir of carbon within the global carbon cycle. Nevertheless, uncertainties remain about the genetic source (e.g., microbial, thermogenic) and possible migration history of natural gas incorporated into hydrate. Previous studies have primarily used the hydrocarbon molecular (CH 4 /C 2 H 6 +) and isotopic (δ 13 C-CH 4 , δ 2 H-CH 4 ) compositions of natural gas to address these uncertainties. However, hydrocarbon tracers are altered by mixing, oxidation, secondary methanogenesis, or fluid migration, which presents challenges when deciphering the mechanisms responsible for methane formation and accumulation. To evaluate the genetic source of natural gases from Green Canyon Block 955 (GC 955), east of the Sigsbee escarpment, we collected and analyzed samples from the first pressurized hydrate-bearing sediment cores collected from a coarse-grained hydrate reservoir in the Gulf of Mexico. Gas samples were analyzed for hydrocarbon gas (C 1 –C 5 ), major gas (e.g., N 2 , CO 2 ), and noble gas (He-Xe) abundance and isotopic (e.g., δ 13 C-CH 4 , δ 2 H-CH 4 , δ 13 C-CO 2 , δ 15 N-N 2 , 3 He/ 4 He, 4 He/ 20 Ne) compositions. We determined that natural gas in hydrates from this location are predominantly of primary microbial origin (conservatively at least 76%) and are formed by the hydrogenotrophic (CO 2 reduction) methanogenesis pathway. We also note increased thermogenic proportions (∼6%) in a hydrate-bearing layer below the main hydrate-bearing interval (separated by a 5-m water-bearing layer). Our results suggest that microbial methane may be abundant below the base of gas hydrate stability at GC 955.

Louisiana↗
USGS2006

The role of the Wetland Reserve Program in conservation efforts in the Mississippi River Alluvial Valley

The Mississippi River Alluvial Valley includes the floodplain of the Mississippi River from Cairo, Illinois, USA, to the Gulf of Mexico. Originally this region supported about 10 million ha of bottomland hardwood forests, but only about 2.8 million ha remain today. Furthermore, most of the remaining bottomland forest is highly fragmented with altered hydrologic processes. During the 1990s landscape-scale conservation planning efforts were initiated for migratory birds and the threatened Louisiana black bear ( Ursus americanus luteolus ). These plans call for large-scale reforestation and restoration efforts in the region, particularly on private lands. In 1990 the Food, Agriculture, Conservation and Trade Act authorized the Wetlands Reserve Program (WRP). The WRP is a voluntary program administered by the United States Department of Agriculture that provides eligible landowners with financial incentives to restore wetlands and retire marginal farmlands from agricultural production. As of 30 September 2005, over 275,700 ha have been enrolled in the program in the Mississippi River Alluvial Valley, with the greatest concentration in Louisiana, Arkansas, and Mississippi, USA. Hydrologic restoration is common on most sites, with open-water wetlands, such as moist-soil units and sloughs, constituting up to 30% of a given tract. Over 33,200 ha of open-water wetlands have been created, potentially providing over 115,000,000 duck-use days. Twenty-three of 87 forest-bird conservation areas have met or exceed core habitat goals for migratory songbirds and another 24 have met minimum area requirements. The WRP played an integral role in the fulfillment of these goals. Although some landscape goals have been attained, the young age of the program and forest stands, and the lack of monitoring, has limited evaluations of the program's impact on wildlife populations.

Mississippi River Alluvial Valley↗
USGS2009

Applications of a broad-spectrum tool for conservation and fisheries analysis: Aquatic gap analysis

Natural resources support all of our social and economic activities, as well as our biological existence. Humans have little control over most of the physical, biological, and sociological conditions dictating the status and capacity of natural resources in any particular area. However, the most rapid and threatening influences on natural resources typically are anthropogenic overuse and degradation. In addition, living natural resources (i.e., organisms) do not respect political boundaries, but are aware of their optimal habitat and environmental conditions. Most organisms have wider spatial ranges than the jurisdictional boundaries of environmental agencies that deal with them; even within those jurisdictions, information is patchy and disconnected. Planning and projecting effects of ecological management are difficult, because many organisms, habitat conditions, and interactions are involved. Conservation and responsible resource use involves wise management and manipulation of the aspects of the environment and biological communities that can be effectively changed. Tools and data sets that provide new insights and analysis capabilities can enhance the ability of resource managers to make wise decisions and plan effective, long-term management strategies. Aquatic gap analysis has been developed to provide those benefits. Gap analysis is more than just the assessment of the match or mis-match (i.e., gaps) between habitats of ecological value and areas with an appropriate level of environmental protection (e.g., refuges, parks, preserves), as the name suggests. Rather, a Gap Analysis project is a process which leads to an organized database of georeferenced information and previously available tools to examine conservation and other ecological issues; it provides a geographic analysis platform that serves as a foundation for aquatic ecological studies. This analytical tool box allows one to conduct assessments of all habitat elements within an area of interest. Aquatic gap analysis naturally focuses on aquatic habitats. The analytical tools are largely based on specification of the species-habitat relations for the system and organism group of interest (Morrison et al. 2003; McKenna et al. 2006; Steen et al. 2006; Sowa et al. 2007). The Great Lakes Regional Aquatic Gap Analysis (GLGap) project focuses primarily on lotic habitat of the U.S. Great Lakes drainage basin and associated states and has been developed to address fish and fisheries issues. These tools are unique because they allow us to address problems at a range of scales from the region to the stream segment and include the ability to predict species specific occurrence or abundance for most of the fish species in the study area. The results and types of questions that can be addressed provide better global understanding of the ecological context within which specific natural resources fit (e.g., neighboring environments and resources, and large and small scale processes). The geographic analysis platform consists of broad and flexible geospatial tools (and associated data) with many potential applications. The objectives of this article are to provide a brief overview of GLGap methods and analysis tools, and demonstrate conservation and planning applications of those data and tools. Although there are many potential applications, we will highlight just three: (1) support for the Eastern Brook Trout Joint Venture (EBTJV), (2) Aquatic Life classification in Wisconsin, and (3) an educational tool that makes use of Google Earth (use of trade or product names does not imply endorsement by the U.S. Government) and Internet accessibility.

Gap Analysis Bulletin↗
USGS2017

Long-term spatial heterogeneity in mallard distribution in the Prairie pothole region

The Prairie Pothole Region (PPR) of north-central United States and south-central Canada supports greater than half of all breeding mallards ( Anas platyrhynchos ) annually counted in North America and is the focus of widespread conservation and research efforts. Allocation of conservation resources for this socioeconomically important population would benefit from an understanding of the nature of spatiotemporal variation in distribution of breeding mallards throughout the 850,000 km 2 landscape. We used mallard counts from the Waterfowl Breeding Population and Habitat Survey to test for spatial heterogeneity and identify high- and low-abundance regions of breeding mallards over a 50-year time series. We found strong annual spatial heterogeneity in all years: 90% of mallards counted annually were on an average of only 15% of surveyed segments. Using a local indicator of spatial autocorrelation, we found a relatively static distribution of low-count clusters in northern Montana, USA, and southern Alberta, Canada, and a dynamic distribution of high-count clusters throughout the study period. Distribution of high-count clusters shifted southeast from northwestern portions of the PPR in Alberta and western Saskatchewan, Canada, to North and South Dakota, USA, during the latter half of the study period. This spatial redistribution of core mallard breeding populations was likely driven by interactions between environmental variation that created favorable hydrological conditions for wetlands in the eastern PPR and dynamic land-use patterns related to upland cropping practices and government land-retirement programs. Our results highlight an opportunity for prioritizing relatively small regions within the PPR for allocation of wetland and grassland conservation for mallard populations. However, the extensive spatial heterogeneity in core distributions over our study period suggests such spatial prioritization will have to overcome challenges presented by dynamic land-use and climate patterns in the region, and thus merits additional monitoring and empirical research to anticipate future population distribution. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

Wildlife Society Bulletin↗
USGS1999

Case 3058. Arctocephalus F. Cuvier, 1826 and Callorhinus Gray, 1859 (Mammalia, Pinnipedia): Proposed conservation by the designation of Phoca pusilla Schreber, [1775] as the type species of Arctocephalus; and Otaria Peron, 1816 and Eumetopias Gill, 1866: proposed conservation by the designation of Phoca leonina Molina, 1782 as the type species of Otaria

The purpose of this application is to conserve the accustomed understanding and usage of the fur seal name Arctocephalus F. Cuvier, 1826 by the designation of Phoca pusilia Schreber, [1775] as the type species, thus conserving also the name Callorhinus Gray, 1859. At present Phoca ursina Linnaeus, 1758 is the valid type species of both Arctocephalus and Callorhinus. The name Arctocephalus relates to a genus of some seven fur seals from the southern hemisphere, while Callorhinus is used for the single species C. ursinus (Linnaeus) from the northern hemisphere. It is also proposed that the universal understanding of the names Otaria Peron, 1816 and Eumetopias Gill, 1866 should be conserved for the southern and northern sea lions respectively by designating Phoca leonina Molina, 1782 (for which the valid specific name is P. byronia de Blainville, 1820) as the type species of Otaria. At present Phoca jubata Schreber, [1776] is the type species of Otaria and the name Otaria is a senior subjective synonym of Eumetopias. The four genera Arctocephalus, Callorhinus, Otaria and Eumetopias are all placed in the family OTARIIDAE Gray, 1825.

Bulletin of Zoological Nomenclature↗
USGS1999

Effects of wind turbines on upland nesting birds in Conservation Reserve Program grasslands

Grassland passerines were surveyed during summer 1995 on the Buffalo Ridge Wind Resource Area in southwestern Minnesota to determine the relative influence of wind turbines on overall densities of upland nesting birds in Conservation Reserve Program (CRP) grasslands. Birds were surveyed along 40 m fixed width transects that were placed along wind turbine strings within three CRP fields and in three CRP fields without turbines. Conservation Reserve Program grasslands without turbines and areas located 180 m from turbines supported higher densities (261.0-312.5 males/100 ha) of grassland birds than areas within 80 m of turbines (58.2-128.0 males/100 ha). Human disturbance, turbine noise, and physical movements of turbines during operation may have disturbed nesting birds. We recommend that wind turbines be placed within cropland habitats that support lower densities of grassland passerines than those found in CRP grasslands.

The Wilson Bulletin↗
USGS2016

New challenges for grizzly bear management in Yellowstone National Park

A key factor contributing to the success of grizzly bear Ursus arctos conservation in the Greater Yellowstone Ecosystem has been the existence of a large protected area, Yellowstone National Park. We provide an overview of recovery efforts, how demographic parameters changed as the population increased, and how the bear management program in Yellowstone National Park has evolved to address new management challenges over time. Finally, using the management experiences in Yellowstone National Park, we present comparisons and perspectives regarding brown bear management in Shiretoko National Park.

Bulletin of the Shiretoko Museum↗
USGS2003

SAS procedures for designing and analyzing sample surveys

Complex surveys often are necessary to estimate occurrence (or distribution), density, and abundance of plants and animals for purposes of re-search and conservation. Most scientists are familiar with simple random sampling, where sample units are selected from a population of interest (sampling frame) with equal probability. However, the goal of ecological surveys often is to make inferences about populations over large or complex spatial areas where organisms are not homogeneously distributed or sampling frames are in-convenient or impossible to construct. Candidate sampling strategies for such complex surveys include stratified,multistage, and adaptive sampling (Thompson 1992, Buckland 1994).

Bulletin of the Ecological Society of America↗
USGS1992

Wildlife species richness in shelterbelts: test of a habitat model

Shelterbelts are human-made habitats consisting of rows of shrubs and trees planted either in fields or on the windward side of farmstead dwellings. Shelterbelts provide wooded habitat for a large variety of birds and other wildlife. A model to predict wildlife species richness in shelterbelts (Schroeder 1986) was published as part of the U.S. Fish and Wildlife Service Habitat Suitability Index (HSI) model series (Schamberger et al. 1982). HSI models have been used extensively by wildlife managers and land use planners to assess habitat quality. Several HSI models have become the focus of a test program that includes analysis of field data for corroboration, refutation, or modification of model hypotheses. Previous tests of HSI models focused either on single species (e.g., Cook and Irwin 1985, Morton et al. 1989, Schroeder 1990) or examined portions of HSI models, such as the relationship between cavity abundance and tree diameter (Allen and Corn 1990). The shelterbelt model, however, assesses habitat value at the community level. The effects of habitat characteristics, area, and perimeter on diversity and abundance of bird and mammal species in shelterbelts were first studied by Yahner (1983a, b). Johnson and Beck (1988) confirmed the importance of shelterbelts to wildlife and identified area, perimeter, and diversity and complexity of vegetation as key measurements of habitat quality. The shelterbelt model incorporates both specific habitat variables and larger scale parameters, such as area and configuration, to predict wildlife species richness. This shift in perspective comes at a time of increasing interest in conservation and planning beyond the species levels (e.g., Graul and Miller 1984, Hutto et al. 1987, Schroeder 1987: 26). We report results of a 3-year study of spatial and vegetative parameters and their relationship to breeding bird species richness (BSR) in 34 Kansas shelterbelts. Our objectives were to test the hypothesis presented in the original shelterbelt model (Schroeder 1986) that species richness can be predicted by shelterbelt characteristics and to investigate alternative models for predicting BSR in shelterbelts.

Kansas↗
USGS2023

Prioritizing the risk and management of introduced species in a landscape with high indigenous biodiversity

Risk analysis protocols for prioritizing the management of non-native species are numerous, yet few incorporate risk and management in the same analysis or accommodate a broad diversity of taxa outside of a specific geographic area. We adapted a protocol that accounts for these factors to address non-native animal species in the Southern California/Northern Baja California Coast Ecoregion near the international border in San Diego County, an area with high indigenous biodiversity and high numbers of species of conservation concern. This stepwise, semi-quantitative protocol is applicable to any animal group in any predefined geographic area, relies on consensus-building among taxonomic experts, and has been vetted through previous use and in peer-reviewed literature. Our results show that the final prioritization was driven mainly by management feasibility, with top-ranked species having multitrophic effects that favor other non-native invaders over native residents. Conditions within the assessment area required some modification to the protocol as it was originally designed, namely a shift in emphasis from eradication to control, given that eradication is implausible for most non-native species in the assessment area. We call attention to taxon-specific issues that surfaced during the analysis, identify areas for improvement in this first-ever risk assessment for invasive animal species in the Natural Communities Conservation Plan/Habitat Conservation Plan (NCCP/HCP) reserve system of San Diego County, and provide suggestions for further refinement of the protocol. This study builds on the effort to standardize risk analysis for invasive species globally, given that many of the same invaders present threats to indigenous biodiversity worldwide.

California↗
USGS1986

An overview of raptor conservation in Latin America

Prior to the last decade, biological studies of raptorial birds in Latin America were almost nonexistent. For many species little more was known than their general range and habitat type. The last few years have seen the opening of a door to what will surely be a flood of scientific investigations. Ultimately, the survival of raptor communities in Latin America depends not only on research but also on several other equally significant conservation efforts. These typically appear in the following order: first, appropriate legislation must be enacted and enforced to provide legal protection; second, the public must be educated concerning the value of wildlife; third, substantial blocks of favourable habitat must be identified and preserved; fourth, economic incentives must be generated so that the local human populations actually benefit from the preservation of vulnerable wildlife and natural habitats; and finally, the long-term success of all of these efforts in each nation depends on the attainment of political, economic and social stability.

Birds of Prey Bulletin↗
USGS1996

Detecting trends in raptor counts: power and type I error rates of various statistical tests

We conducted simulations that estimated power and type I error rates of statistical tests for detecting trends in raptor population count data collected from a single monitoring site. Results of the simulations were used to help analyze count data of bald eagles (Haliaeetus leucocephalus) from 7 national forests in Michigan, Minnesota, and Wisconsin during 1980-1989. Seven statistical tests were evaluated, including simple linear regression on the log scale and linear regression with a permutation test. Using 1,000 replications each, we simulated n = 10 and n = 50 years of count data and trends ranging from -5 to 5% change/year. We evaluated the tests at 3 critical levels (alpha = 0.01, 0.05, and 0.10) for both upper- and lower-tailed tests. Exponential count data were simulated by adding sampling error with a coefficient of variation of 40% from either a log-normal or autocorrelated log-normal distribution. Not surprisingly, tests performed with 50 years of data were much more powerful than tests with 10 years of data. Positive autocorrelation inflated alpha-levels upward from their nominal levels, making the tests less conservative and more likely to reject the null hypothesis of no trend. Of the tests studied, Cox and Stuart's test and Pollard's test clearly had lower power than the others. Surprisingly, the linear regression t-test, Collins' linear regression permutation test, and the nonparametric Lehmann's and Mann's tests all had similar power in our simulations. Analyses of the count data suggested that bald eagles had increasing trends on at least 2 of the 7 national forests during 1980-1989.

Wildlife Society Bulletin↗
USGS2022

Earthquake early warning for estimating floor shaking levels of tall buildings

This article investigates methods to improve earthquake early warning (EEW) predictions of shaking levels for residents of tall buildings. In the current U.S. Geological Survey ShakeAlert EEW system, regions far from an epicenter will not receive alerts due to low predicted ground‐shaking intensities. However, residents of tall buildings in those areas may still experience significant shaking due to the acceleration amplification caused by tall buildings’ dynamic behavior, as recently experienced by residents of the 52‐story building in downtown Los Angeles (DTLA) during the 2019 M 7.1 Ridgecrest earthquake. Using more than 400 recorded response data acquired from 77 instrumented buildings in California, here we compare the Federal Emergency Management Agency (FEMA) P‐58 and American Society of Civil Engineers (ASCE) 7‐16 simplified equations for peak floor acceleration (PFA), finding that the ASCE estimation is close to the median of data recorded in large and long‐distance events, whereas the current FEMA estimation is not suitable. In the second part of this article, four instrumented tall buildings in DTLA are extensively studied, and the performance of the simplified and response spectrum (RS) methods giving both an estimation of the free‐field horizontal peak ground acceleration (PGA) and pseudospectral acceleration is evaluated. The results show that the RS method is as accurate as the response history analysis as long as the ground‐motion RS is accurate, whereas the ASCE 7‐16 prediction is conservative. However, when ground‐motion RS or PGA is estimated for DTLA using a ground‐motion model (GMM), the performance of the RS method significantly degrades due to underestimation by the GMM at long periods. The results of this study imply that a nonergodic GMM, which may give more accurate prediction in Los Angeles, could improve the results for PFA when the building’s behavior is dominated by a few long‐period fundamental modes, as is the case for the 52‐story building in DTLA.

California↗
USGS2014

Earthquake intensity distributions: a new view

Pioneering work by Nicolas Ambraseys and many collaborators demonstrates both the tremendous value of macroseismic data and the perils of its uncritical assessment. In numerous publications he shows that neglect of original sources and/or failure to appreciate the context of historical accounts, as well as use of unreliable indicators such as landslid- ing to determine intensities, commonly leads to inflated magnitude estimates for historical earthquakes. The U.S. Geological Survey “Did You Feel It?” (DYFI) system, which now collects and systematically interprets thousands of first-hand reports from felt earthquakes, provides the opportunity to explore further the biases associated with traditional intensity distributions determined from written (media or archival) accounts. I briefly summarize and further develop the results of Hough (2013), who shows that traditional intensity distrib- utions imply more dramatic damage patterns than are documented by more spatially rich DYFI data, even when intensities are assigned according to the conservative practices estab- lished by Ambraseys’ work. I further consider the separate intensity–attenuation relations that have been developed to characterize intensities for historical and modern earthquakes in California, using traditionally assigned intensities and DYFI intensities, respectively. The results support the conclusion that traditionally assigned intensity values tend to be inflated by a fundamental bias towards reporting of dramatic rather than representative effects. I introduce an empirical correction-factor approach to correct for these biases. This allows the growing wealth of well-calibrated DYFI data to be used as calibration events in the analysis of historical earthquakes

Bulletin of Earthquake Engineering↗