Search USGS⌕ Search

SEARCH · Search USGS

Results for “Natural Hazards Observer”

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

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
USGS2016

2016 one-year seismic hazard forecast for the Central and Eastern United States from induced and natural earthquakes

The U.S. Geological Survey (USGS) has produced a 1-year seismic hazard forecast for 2016 for the Central and Eastern United States (CEUS) that includes contributions from both induced and natural earthquakes. The model assumes that earthquake rates calculated from several different time windows will remain relatively stationary and can be used to forecast earthquake hazard and damage intensity for the year 2016. This assessment is the first step in developing an operational earthquake forecast for the CEUS, and the analysis could be revised with updated seismicity and model parameters. Consensus input models consider alternative earthquake catalog durations, smoothing parameters, maximum magnitudes, and ground motion estimates, and represent uncertainties in earthquake occurrence and diversity of opinion in the science community. Ground shaking seismic hazard for 1-percent probability of exceedance in 1 year reaches 0.6 g (as a fraction of standard gravity [g]) in northern Oklahoma and southern Kansas, and about 0.2 g in the Raton Basin of Colorado and New Mexico, in central Arkansas, and in north-central Texas near Dallas. Near some areas of active induced earthquakes, hazard is higher than in the 2014 USGS National Seismic Hazard Model (NHSM) by more than a factor of 3; the 2014 NHSM did not consider induced earthquakes. In some areas, previously observed induced earthquakes have stopped, so the seismic hazard reverts back to the 2014 NSHM. Increased seismic activity, whether defined as induced or natural, produces high hazard. Conversion of ground shaking to seismic intensity indicates that some places in Oklahoma, Kansas, Colorado, New Mexico, Texas, and Arkansas may experience damage if the induced seismicity continues unabated. The chance of having Modified Mercalli Intensity (MMI) VI or greater (damaging earthquake shaking) is 5–12 percent per year in north-central Oklahoma and southern Kansas, similar to the chance of damage caused by natural earthquakes at sites in parts of California.

Open-File Report↗
USGS2016

Shallower structure and geomorphology of the southern Puerto Rico offshore margin

Oblique convergence between the North American and Caribbean plates along the eastern Greater Antilles island arc has yielded the compressive Muertos margin in the backarc region. The Muertos margin is characterized by an asymmetric thrust belt with overall opposite vergence to the subduction system in the forearc region. Offshore south of Puerto Rico, this thrust belt disappears and is replaced by a succession of NE─SW- and E─W-trending deep basins and steep ridges that characterize the western Anegada passage, resulting in a complex deformation pattern. Using new high-resolution multibeam bathymetry and a dense data set of mostly new seismic reflection profiles, we studied the along- and across-strike variations of the geomorphology and shallower structure of the southern Puerto Rico offshore margin. We have identified four morphotectonic provinces: the Puerto Rican sub-basin and Muertos trough, the Muertos margin, the insular shelf and the western Anegada passage. The Muertos margin province shows two distinct slope sub-provinces: the active Muertos thrust belt formed by N─S-compression between the island arc and the Caribbean plate’s interior ─which includes lower and upper thrust belts with distinct deformational styles and lateral continuity─ and the shelf slope covered by a thick package of layered sediments highly-incised by a dense canyon network. This network is disrupted by the Investigator fault zone consisting of a 130 km-long E─W-trending band of active extensional deformation. The Investigator fault zone shows differential surface expression caused by along-strike changes in the magnitude and distribution of the deformation, though this deformation is driven by a N─S-oriented extension, and if there is any amount of strike-slip it is insignificant. In the western Anegada passage province, the Whiting basin and Whiting and Grappler ridges are formed by large dipslip normal faults driven by a NW─SE-oriented extensional regime. The western St. Croix rise shows a complex structure as attested by the existence of NE─SW- and E─W-oriented normal faults. The NE─SW-trending NW-dipping normal faults observed at the summit of the rise predate the E─W-bounding faults that could accommodate the extensional deformation at the Present. This study provides detailed observations on the active tectonic and sedimentary processes to help future studies assessing the natural resources and the seismic and tsunamigenic hazard in the Puerto Rico region.

Marine and Petroleum Geology↗
USGS2016

Kriging and local polynomial methods for blending satellite-derived and gauge precipitation estimates to support hydrologic early warning systems

Robust estimates of precipitation in space and time are important for efficient natural resource management and for mitigating natural hazards. This is particularly true in regions with developing infrastructure and regions that are frequently exposed to extreme events. Gauge observations of rainfall are sparse but capture the precipitation process with high fidelity. Due to its high resolution and complete spatial coverage, satellite-derived rainfall data are an attractive alternative in data-sparse regions and are often used to support hydrometeorological early warning systems. Satellite-derived precipitation data, however, tend to underrepresent extreme precipitation events. Thus, it is often desirable to blend spatially extensive satellite-derived rainfall estimates with high-fidelity rain gauge observations to obtain more accurate precipitation estimates. In this research, we use two different methods, namely, ordinary kriging and κ-nearest neighbor local polynomials, to blend rain gauge observations with the Climate Hazards Group Infrared Precipitation satellite-derived precipitation estimates in data-sparse Central America and Colombia. The utility of these methods in producing blended precipitation estimates at pentadal (five-day) and monthly time scales is demonstrated. We find that these blending methods significantly improve the satellite-derived estimates and are competitive in their ability to capture extreme precipitation.

IEEE Transactions on Geoscience and Remote Sensing↗
USGS2006

Volcanic hazards at Atitlan volcano, Guatemala

Atitlan Volcano is in the Guatemalan Highlands, along a west-northwest trending chain of volcanoes parallel to the mid-American trench. The volcano perches on the southern rim of the Atitlan caldera, which contains Lake Atitlan. Since the major caldera-forming eruption 85 thousand years ago (ka), three stratovolcanoes--San Pedro, Toliman, and Atitlan--have formed in and around the caldera. Atitlan is the youngest and most active of the three volcanoes. Atitlan Volcano is a composite volcano, with a steep-sided, symmetrical cone comprising alternating layers of lava flows, volcanic ash, cinders, blocks, and bombs. Eruptions of Atitlan began more than 10 ka [1] and, since the arrival of the Spanish in the mid-1400's, eruptions have occurred in six eruptive clusters (1469, 1505, 1579, 1663, 1717, 1826-1856). Owing to its distance from population centers and the limited written record from 200 to 500 years ago, only an incomplete sample of the volcano's behavior is documented prior to the 1800's. The geologic record provides a more complete sample of the volcano's behavior since the 19th century. Geologic and historical data suggest that the intensity and pattern of activity at Atitlan Volcano is similar to that of Fuego Volcano, 44 km to the east, where active eruptions have been observed throughout the historical period. Because of Atitlan's moderately explosive nature and frequency of eruptions, there is a need for local and regional hazard planning and mitigation efforts. Tourism has flourished in the area; economic pressure has pushed agricultural activity higher up the slopes of Atitlan and closer to the source of possible future volcanic activity. This report summarizes the hazards posed by Atitlan Volcano in the event of renewed activity but does not imply that an eruption is imminent. However, the recognition of potential activity will facilitate hazard and emergency preparedness.

Open-File Report↗
USGS2012

Observations constraining near-source ground motion estimated from locally recorded seismograms

To estimate the seismic hazard to underground facilities or operations in the environs of a mining-induced tremor or a natural earthquake, it is useful to be able to relate locally recorded seismic waveforms to peak ground velocity and slip at the causative fault. For this purpose, far-field S wave pulses are analyzed to define the faulting slip D and near-fault peak ground velocity D /2 that give rise to the most significant ground motion. This most intense region of faulting, an assumed circular asperity, has radius r within a broader source zone of radius r 0 , which is traditionally calculated from the corner frequency of the S wave spectrum. In developing relationships between peak far-field velocity v and peak acceleration a, and the source processes of the asperity, D and D , as well as its radius r , the key model assumption is that r = k β/ω, where ω is the angular frequency of the sinusoidal velocity pulse of maximum amplitude, β is the sheaf wave speed, and k is a constant. Observations in deep-level gold mines of fault slip and slip velocity as well as laboratory observations of slip rate as a function of stress drop for stick-slip failure support a choice of about k = 2.34, the value commonly used for estimating r 0 using the Brune model. In particular, observations of fault slip up to 410 mm for mining-induced tremors in the moment magnitude range 4–5 are consistent with D = 8.1 R v/β, where R is hypocentral distance. Moreover, estimates based on underground damage of near-fault ground velocities ranging up to 3.5 m/s are in accord with D /2 = 1.28(β/μ) ρ R a, where μ is the modulus of rigidity and ρ is the density. Alternatively, the average slip velocity 〈 D 〉 can be expressed in terms of the stress drop Δσ a of the asperity as 〈 D 〉 = 0.51 β Δσ a /μ, and the agreement of this relationship with measurements made during stick-slip failure in the laboratory is good. To the extent that seismic slip exterior to the asperity is a consequence of preevent suppression of slip due to the asperity, the broader-scale( r 0 ) slip can be related to that of the asperity. Just as the asperity radius r can be estimated from r = 2.34 βv/a, an alternative estimate for r 0 is given by r 0 = ρ R a M 0 /[75.8ρμ( R v) 2 ], the results of which are generally in good agreement with estimates based on the spectral corner frequency method.

Journal of Geophysical Research↗
USGS2013

Variability of displacement at a point: Implications for earthquake‐size distribution and rupture hazard on faults

To investigate the nature of earthquake‐magnitude distributions on faults, we compare the interevent variability of surface displacement at a point on a fault from a composite global data set of paleoseismic observations with the variability expected from two prevailing magnitude–frequency distributions: the truncated‐exponential model and the characteristic‐earthquake model. We use forward modeling to predict the coefficient of variation (CV) for the alternative earthquake distributions, incorporating factors that would effect observations of displacement at a site. The characteristic‐earthquake model (with a characteristic‐magnitude range of ±0.25) produces CV values consistent with the data (CV∼0.5) only if the variability for a given earthquake magnitude is small. This condition implies that rupture patterns on a fault are stable, in keeping with the concept behind the model. This constraint also bears upon fault‐rupture hazard analysis, which, for lack of point‐specific information, has used global scaling relations to infer variability in average displacement for a given‐size earthquake. Exponential distributions of earthquakes (from M 5 to the maximum magnitude) give rise to CV values that are significantly larger than the empirical constraint. A version of the model truncated at M 7, however, yields values consistent with a larger CV (∼0.6) determined for small‐displacement sites. Although this result allows for a difference in the magnitude distribution of smaller surface‐rupturing earthquakes, it may reflect, in part, less stability in the displacement profile of smaller ruptures and/or the tails of larger ruptures.

Bulletin of the Seismological Society of America↗
USGS1999

Assessment of landslide hazards in Kaluanui and Maakua gulches, Oahu, Hawaii, following the 9 May 1999 Sacred Falls landslide

One of the injured hikers later died of injuries received in the landslide. Governor Ben Cayetano of Hawaii ordered that the park be closed due to concern about continuing landslide hazard near the falls. Subsequently, Bill Meyer, District Chief for the U.S. Geological Survey (USGS) Water Resources Division in Honolulu contacted Tim Johns, Chair of the Board of Land and Natural Resources of the Hawaii Department of Land and Natural Resources (DLNR) and offered assistance in assessing slope stability in the park. Mr. Johns accepted the offer, and two landslide specialists from the USGS Geologic Hazards Team in Golden Colorado were sent to the site. On Friday, 14 May 1999, we visited the Sacred Falls landslide site with Glenn Bauer, Ed Sakoda, and Gary Moniz of DLNR. The ground investigation involved inspecting the impact area, estimating the volume of the deposit, and gathering data to help reconstruct the event. On Monday, 17 May 1999, we conducted an aerial reconnaissance of Kaluanui Gulch (Sacred Falls State Park) and Maakua Gulch in a commercial helicopter provided by DLNR. We inspected the source and path of movement of the Sacred Falls landslide of 9 May and reconnoitered the full length of both valleys to get an overview of ongoing landslide hazards there. This report gives our observations and conclusions about the Sacred Falls landslide, broadly assesses the ongoing hazard in the Kaluanui and Maakua Gulches, and suggests methods for more detailed assessment of landslide hazards here and along other trails in state parks on Oahu. Observations and conclusions in this report are based on a very brief investigation and thus are preliminary in nature.

Hawaii↗
USGS2019

Induced seismicity reduces seismic hazard?

Earthquakes caused by human activities have been observed for decades. Often these are related to industrial activities pumping fluids into deep geologic formations, like with wastewater disposal. The simplest theory connecting these processes to earthquakes is straightforward: injection leads to fluid pressure changes that either reduce the strength of preexisting faults or generate new faults. In practice, the conditions that lead to induced earthquakes are not always clear in ways that can be generalized. Kao et al. (2018, https://doi.org/10.1029/2018GL079288) show how the distribution of induced earthquakes in Western Canada relate to natural rates of deformation in the crust. Using these new results, they discuss an intriguing paradox: induced seismicity can cause short-term increases in the seismic hazard that are followed by a period of reduced seismic hazard. Such hazard-reducing scenarios are plausible but hinge upon simplifying assumptions about how the crust stores and releases strain energy in the form of earthquakes.

Geophysical Research Letters↗
USGS2021

Geologic controls of slow-moving landslides near the U.S. West Coast

Slow-moving landslides, often with nearly imperceptible creeping motion, are an important landscape shaper and a dangerous natural hazard across the globe, yet their spatial distribution and geologic controls are still poorly known owing to a paucity of detailed, large-area observations. Here, we use interferometry of L-band satellite radar images to reveal 617 spatially large (4 × "> × 10 4 – 13 × "> × 10 6 m 2 ) and presently active (2007 – 2019) slow-moving landslides near the populous US West Coast (only 4.6% of these slides were previously known) and provide evidence for their fundamental controls by bedrock lithology and vertical land motion. We found that slow-moving landslides are generally larger and more spatially frequent in homogeneous bedrock with low rock strength, and they are preferentially located on hillslopes with geologically recent uplift. Notably, landslide size and spatial density in the relatively weak metamorphic rocks and mélange (due to pervasive tectonically sheared discontinuities, foliation, and abundant clay minerals) were two times larger than those in sedimentary and igneous rocks, and the hillslopes with landslides were found to be uplifting approximately three times faster than the average for the whole region. These results suggest that slow-moving landslides can be effectively uncovered by satellite radar imagery and their occurrence and character may be anticipated from vertical land uplift and bedrock lithology. Hence, our study provides understanding critical for reducing landslide hazards and quantifying landslide impacts on landscape change.

California, Oregon, Washington↗
USGS2022

Statistical consideration of nonrandom treatment applications reveal region-wide benefits of widespread post-fire restoration action

Accurate predictions of ecological restoration outcomes are needed across the increasingly large landscapes requiring treatment following disturbances. However, observational studies often fail to account for nonrandom treatment application, which can result in invalid inference. Examining a spatiotemporally extensive management treatment-- post-fire seeding of declining sagebrush shrubs across the semiarid U.S. over two decades -- we quantify drivers and consequences of selection biases in restoration, using remotely sensed data. Treatments were disproportionately applied in more stressful, degraded ecological conditions. Failure to incorporate nonrandom treatment allocation led to the conclusion that costly, widespread seedings were unsuccessful; however, after considering biases, restoration positively affected sagebrush recovery. Treatment effect sizes varied with climate, indicating possible prioritization criteria for interventions. Our findings revise the perspective that widespread post-fire sagebrush seedings have been broadly “unsuccessful” and demonstrate how selection biases can pose substantive inferential hazards in observational studies of restoration efficacy and development of restoration theory.

California, Colorado, Idaho, Nevada, Oregon, Utah,↗
USGS2011

The role of dyking and fault control in the rapid onset of eruption at Chaitén Volcano, Chile

Rhyolite is the most viscous of liquid magmas, so it was surprising that on 2 May 2008 at Chaitén Volcano, located in Chile’s southern Andean volcanic zone, rhyolitic magma migrated from more than 5 km depth in less than 4 hours and erupted explosively with only two days of detected precursory seismic activity . The last major rhyolite eruption before that at Chaitén was the largest volcanic eruption in the twentieth century, at Novarupta volcano, Alaska, in 1912. Because of the historically rare and explosive nature of rhyolite eruptions and because of the surprisingly short warning before the eruption of the Chaitén volcano, any information about the workings of the magmatic system at Chaitén, and rhyolitic systems in general, is important from both the scientific and hazard perspectives. Here we present surface deformation data related to the Chaitén eruption based on radar interferometry observations from the Japan Aerospace Exploration Agency (JAXA) DAICHI (ALOS) satellite. The data on this explosive rhyolite eruption indicate that the rapid ascent of rhyolite occurred through dyking and that melt segregation and magma storage were controlled by existing faults.

Chaitén Volcano↗
USGS2015

Geologic map of the southern White Ledge Peak and Matilija quadrangles, Santa Barbara and Ventura Counties, California

This report presents a digital geologic strip map of the southern parts of the contiguous White Ledge Peak and Matilija 7.5’ quadrangles in coastal southern California. With a compilation scale of 1:24,000 (one inch on the map to 2,000 feet on the ground), the map depicts the distribution of bedrock units, surficial deposits, and associated deformation adjacent to and south of the Arroyo Parida fault and in the southern Ojai Valley east of the Ventura River. This new compilation, combined with a recently published geologic map of the Santa Barbara coastal plain (U.S. Geological Survey Scientific Investigations Map 3001), completes a 69-km-long east-west mapping transect from Goleta to Ojai by the U.S. Geological Survey. These two contiguous geologic maps provide new insights and constraints on Neogene-through-Quaternary tectonic deformation and consequent landscape change, including geohazards in the urbanized southern flank of the Santa Ynez Mountains. A principal aim of the new mapping and associated fault-kinematic measurements is to document and constrain the nature of transpressional strain transfer between various regional, potentially seismogenic faults. In the accompanying pamphlet, surficial and bedrock map units are described in detail as well as a summary of the structural and fault-kinematic framework of the map area. New biostratigraphic and biochronologic data based on microfossil identifications are presented in expanded unit descriptions of the marine Neogene Monterey and Sisquoc Formations. Site-specific fault kinematic observations are embedded in the digital map database. This compilation provides a uniform geologic digital geodatabase and map plot files that can be used for visualization, analysis, and interpretation of the area’s geology, geologic hazards, and natural resources.

California↗
USGS2002

Challenges in observational seismology

Earthquake seismology became a quantitative scientific discipline after instruments were developed to record seismic waves in the late 19th century ( Dewey and Byerly, 1969 ; Chapter 1 by Agnew). Earthquake seismology is essentially based on field observations. The great progress made in the past several decades was primarily due to increasingly plentiful and high-quality data that are readily distributed. Our ability to collect, process, and analyze earthquake data has been accelerated by advances in electronics, communications, computers, and software (see Chapter 85 edited by Snoke and Garcia-Fernandez). Instrumental observation of earthquakes has been carried out for a little over 100 years by seismic stations and networks of various sizes, from local to global scales (see Chapter 87 edited by Lahr and van Eck). The observed data have been used, for example, (1) to compute the source parameters of earthquakes, (2) to determine the physical properties of the Earth's interior, (3) to test the theory of plate tectonics , (4) to map active faults, (5) to infer the nature of damaging ground shaking, and (6) to carry out seismic hazard analysis. Construction of a satisfactory theory of the earthquake process has not yet been achieved within the context of physical laws. Good progress, however, has been made in building a physical foundation of the earthquake source process, partly as a result of research directed toward earthquake prediction. This chapter is intended for a general audience. Technical details are not given, but relevant references and chapters in this Handbook are referred to. The first part of this chapter presents a brief overview of the observational aspects of earthquake seismology, concentrating on instrumental observations of seismic waves generated by earthquakes (i.e., seismic monitoring), and readers are referred to Chapter 49 by Musson and Cecic for noninstrumental observations. A few key developments and practices are summarized by taking a general view, since many national and regional developments have been chronicled in national and institutional reports (see Chapter 79 edited by Kisslinger). In the latter part of this chapter, the nature of seismic monitoring and some challenges in observational seismology are discussed from a personal perspective. Comments of a technical or philosophical nature are given in the Notes at the end of the chapter, and they are referenced by superscript numbers in the text.

International Geophysics↗
USGS2023

Combining field observations and high-resolution numerical modeling to demonstrate the effect of coral reef roughness on turbulence and its implications for reef restoration design

Coral reefs are effective natural barriers that protect adjacent coastal communities from hazards such as erosion and storm-induced flooding. However, the degradation of coral reefs compromises their ability to protect against these hazards, making degraded reefs a target for restoration. There have been limited field and numerical modeling studies conducted to understand how an increase in coral reef roughness, as would occur due to restoration, can affect wave energy dissipation for a range of real-world wave and water level conditions. To address this knowledge gap, field measurements were collected over adjacent low-roughness and high-roughness reefs off Molokaʻi, Hawaiʻi, USA, subjected to the same oceanographic forcing. Those field data were then used to calibrate and validate OpenFOAM computational fluid dynamics models of the reef. These calibrated models were then used to explore energy dissipation for a range of wave conditions based on measurements from a suite of existing datasets and values from the literature. In general, wave dissipation scales with incident wave conditions, where greater dissipation occurred for shallow depths and shorter-period waves. This tendency for short-period waves to be more readily attenuated is supported by wave energy dissipation factors in the range of 0.1–5, which decline with increasing wave period. Near-bed turbulent kinetic energy dissipation also scales with incident wave conditions, where the greatest difference in dissipation between low and high relief cases occurs for short wave periods. Turbulence becomes less affected by bottom roughness as the wave period increases. Based on this study, wave attenuation and turbulent energy dissipation could be enhanced by 0.5–1 order of magnitude (45% per across-shore meter) if the seabed roughness at the field site were increased by 13%, an achievable goal in coral reef restoration.

Coastal Engineering↗
USGS1981

United States Geological Survey Yearbook, fiscal year 1980

It is not very often that a single event is so overwhelming that it changes public perceptions of natural hazards for generations. Perhaps for the U.S. Geological Survey, the explosive volcanic activity of Mount St. Helens began such a change. After 101 years of careful science of the Earth's past and meticulous observations and assessments of the present, predictive earth science was in full public view. However vague and faint the glimpse of the future made possible by earth science, it was enough. Warnings were issued, thousands of lives were saved, and the age of real-time geology began. The Survey's basic mission has not changed, but the power of our analytical tools has increased by several orders of magnitude. The Survey's efforts to understand Earth processes and hydrologic principles continued with the collection, during fiscal year 1980, of valuable new data on the geologic origin and framework, seismicity, and mineral and energy resources of the United States. The Survey is also responsible for classification of the leasable minerals on Federal lands and the regulation of mineral exploration and development activities on Federal and Indian lands. As the principal earth science fact-gathering agency, the Survey provides information for sound decisionmaking by government and private industry. Industry uses the Survey's information in exploring for energy and minerals and improving their efforts to make development of energy and minerals compatible with environmental protection standards. Government uses the Survey's information in conducting leasing operations on public lands, in regulating the safe design and siting of nuclear plants, and in establishing guidelines for determining and locating areas that are subject to geologic hazards such as landslides, earthquakes, and volcanic eruptions. The Yearbook reports a broad range of the Survey's accomplishments during the past fiscal year and provides an overview of future directions. Many of the topics covered will continue to be important natural resource and earth science issues of the 1980's.

Yearbook↗
USGS2021

Landslides triggered by the August 14, 2021, magnitude 7.2 Nippes, Haiti, earthquake

The August 14, 2021, magnitude 7.2 Nippes, Haiti, earthquake triggered thousands of landslides on the Tiburon Peninsula. The landslides directly caused fatalities and damage and impeded response efforts by blocking roads and causing other infrastructure damage. Adverse effects of the landslides likely will continue for months to years. This report presents an assessment of potential postearthquake landslide-related geologic hazards for the Tiburon Peninsula and a preliminary map of the landslides triggered by the earthquake. This hazard assessment is based on an emergency analysis of the currently available, postearthquake satellite imagery. In this report, we highlight specific areas of concern that may benefit from more detailed assessment and longer-term monitoring. Our mapping efforts revealed that at least 4,893 landslides were triggered across the Tiburon Peninsula by the earthquake and subsequent rainfall from Tropical Cyclone Grace. We also observed hundreds of landslide deposits potentially restricting flow in rivers and streams. In addition, we observed landslides that likely affected roads by rendering them impassable or susceptible to subsequent damage from existing landslides. Because of the preliminary nature of this report and the limits of remote analyses, additional investigation and monitoring would be beneficial to accurately determine the threat posed by these hazards to people and infrastructure.

Nippes↗
USGS2019

Imaging spectroscopy for the detection, assessment and monitoring of natural and anthropogenic hazards

Natural and anthropogenic hazards have the potential to impact all aspects of society including its economy and the environment. Diagnostic data to inform decision-making are critical for hazard management whether for emergency response, routine monitoring or assessments of potential risks. Imaging spectroscopy (IS) has unique contributions to make via the ability to provide some key quantitative diagnostic information. In this paper, we examine a selection of key case histories representing the state of the art to gain an insight into the achievements and perspectives in the use of visible to shortwave infrared IS for the detection, assessment and monitoring of a selection of significant natural and anthropogenic hazards. The selected key case studies examined provide compelling evidence for the use of the IS technology and its ability to contribute diagnostic information currently unattainable from operational spaceborne Earth observation systems. User requirements for the applications were also evaluated. The evaluation showed that the projected launch of spaceborne IS sensors in the near-, mid and long term future, together with the increasing availability, quality and moderate cost of off the shelf sensors, the possibilities to couple unmanned autonomous systems with miniaturized sensors, should be able to meet these requirements. The challenges and opportunities for the scientific community in the future when such data become available will then be ensuring consistency between data from different sensors, developing techniques to efficiently handle, process, integrate and deliver the large volumes of data, and most importantly translating the data to information that meets specific needs of the user community in a form that can be digested/understood by them. The latter is especially important to transforming the technology from a scientific to an operational tool. Additionally, the information must be independently validated using current trusted practices and uncertainties quantified before IS derived measurement can be integrated into operational monitoring services.

Colorado↗
USGS2014

Hydrogeology of the Old Faithful area, Yellowstone National Park, Wyoming, and its relevance to natural resources and infrastructure

A panel of leading experts (The Old Faithful Science Review Panel) was convened by Yellowstone National Park (YNP) to review and summarize the geological and hydrological understanding that can inform National Park Service management of the Upper Geyser Basin area. We give an overview of present geological and hydrological knowledge of the Old Faithful hydrothermal (hot water) system and related thermal areas in the Upper Geyser Basin. We prioritize avenues for improving our understanding of key knowledge gaps that limit informed decision-making regarding human use in this fragile natural landscape. Lastly, we offer guidelines to minimize impacts to the hydrothermal system that could be used to aid decisions by park management. Old Faithful sits within the Upper Geyser Basin, an area of abundant hydrothermal activity where boiling waters extend from the surface to significant depth within glacial sediments and underlying volcanic rocks. The geyser systems are directly fed by waters recharged decades to millennia ago, which are surrounded by colder, younger waters. Activity of the geysers is controlled by complex subsurface plumbing with fractures and conduits separated by regions of low permeability. Observations over the past century indicate that the thermal areas and their features are both fragile and highly dynamic. Although Old Faithful has erupted regularly for the past 150 years, it exhibits changes in eruptive behavior over time, and the average interval between eruptions has increased by about 50 percent over the past 50 years. It is clear that human activity has modified the hydrothermal system in the past; conversely, natural features pose ongoing hazards to humans and human infrastructure. Current (2014) long-term programs to measure heat discharge by chloride-flux monitoring, and more recently by thermal-infrared imaging, are crucial for assessing the status of the hydrothermal system. Complementary studies could include airborne resistivity, environmental tracers, numerical modeling, and greater emphasis on measuring the discharge of water during geyser eruptions. Such data are needed to better understand the subsurface plumbing systems that feed the geysers. Further understanding can be gained through installation of shallow groundwater observation wells, surface geophysical studies, and direct measurement of temperature gradients near the surface. It also is critical to archive existing data from all studies in a manner that will be readily accessible to scientists and decision makers. Monitoring and data collection can be achieved through the YNP geology program, by direct funding to other groups, or by encouraging and facilitating externally funded research. There are many documented examples at YNP and elsewhere where human infrastructure and natural thermal features have negatively affected each other. Unless action is taken, human conflicts with the Old Faithful hydrothermal system are likely to increase over the coming years. This is partly because of the increase in park visitation over the past decades, but also because the interval between eruptions of Old Faithful has increased, lengthening the time spent (and services needed) for each visitor at Old Faithful. To avoid an increase in visitor impacts, the National Park Service should consider 2 alternate strategies to accommodate people, vehicles, and services in the Upper Geyser Basin, such as shuttle services from staging (parking and dining) areas with little or no recent hydrothermal activity. We further suggest that YNP consider a zone system to guide maintenance and development of infrastructure in the immediate Old Faithful area. A “red” zone includes hydrothermally active land where new development is discouraged and existing infrastructure is modified with great care. An outer “green” zone represents areas where cooler temperatures and less hydrothermal flow are thought to exist, and where development and maintenance could proceed as occurs elsewhere in the park. An intermediate “yellow” zone would require preliminary assessment of subsurface temperatures and gas concentrations to assess suitability for infrastructure development. The panel recommends that YNP management follow the lead of the National Park System Advisory Board Science Committee (2012) by applying the “precautionary principle” when making decisions regarding the interaction of hydrothermal phenomena and park infrastructure in the Old Faithful area and other thermal areas within YNP.

Wyoming↗