Regional Seismic Network Monitoring in the Eastern Intermountain West

2019 ◽  
Vol 91 (2A) ◽  
pp. 631-646 ◽  
Author(s):  
Kristine L. Pankow ◽  
Michael Stickney ◽  
Jeri Y. Ben-Horin ◽  
Mairi Litherland ◽  
Suzette Payne ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Sierra Nevada ◽  
Great Plains ◽  
Active Regions ◽  
Seismic Monitoring ◽  
Historical Seismicity ◽  
Military Bases ◽  
Intermountain West ◽  
Critical Facilities ◽  
Seismic Networks

Abstract The Intermountain West (IMW) region is bounded by the Sierra Nevada Mountains to the west and the Great Plains to the east. Tectonically, the region is dominated by active extension and has moderate to high seismic hazard. Both paleoseismic and historical records include M>7 surface-rupturing earthquakes. The region is also the location of frequent moderate-size (M 5–6) earthquakes. In this article, we focus on the eastern IMW and its six regional seismic networks. We document recent and historical seismicity, describe the evolution of the regional networks, and clarify the rationale for sustained and improved seismic monitoring. Although absolute population is relatively low compared with other parts of the country, the IMW is experiencing rapid growth. Beyond population, there is significant seismic risk posed to major transportation and energy corridors, nuclear generation and storage facilities, dams, national laboratories, military bases, and other critical facilities. Despite the relatively high seismic hazard and increasing risk, seismic monitoring varies from excellent to skeletal, with some seismically active regions having minimal seismographic coverage. Clear monitoring needs for the IMW include increased station density, replacement of outdated seismic equipment, and more stable funding.

Review of Seismic Hazard Issues Associated with Auburn Dam Project, Sierra Nevada Foothills, California

1996 ◽  
Author(s):  
D.P. Schwartz ◽  
W.B. Joyner ◽  
R.S. Stein ◽  
R.D. Brown ◽  
A.F. McGarr ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Sierra Nevada ◽  
Sierra Nevada Foothills

A multidisciplinary approach to seismic hazard in southern California

1994 ◽  
Vol 84 (5) ◽  
pp. 1293-1309
Author(s):  
Steven N. Ward
Keyword(s):  
Seismic Hazard ◽  
Southern California ◽  
Current Model ◽  
Seismic Hazard Assessment ◽  
Historical Seismicity ◽  
San Andreas ◽  
The Pacific ◽  
Moderate Earthquake ◽  
Earthquake Potential ◽  
Seismic Moment Release

Abstract A serious obstacle facing seismic hazard assessment in southern California has been the characterization of earthquake potential in areas far from known major faults where historical seismicity and paleoseismic data are sparse. This article attempts to fill the voids in earthquake statistics by generating “master model” maps of seismic hazard that blend information from geology, paleoseismology, space geodesy, observational seismology, and synthetic seismicity. The current model suggests that about 40% of the seismic moment release in southern California could occur in widely scattered areas away from the principal faults. As a result, over a 30-yr period, nearly all of the region from the Pacific Ocean to 50 km east of the San Andreas Fault has a greater than 50/50 chance of experiencing moderate shaking of 0.1 g or greater, and about a 1 in 20 chance of suffering levels exceeding 0.3 g. For most of the residents of southern California, thelion's share of hazard from moderate earthquake shaking over a 30-yr period derives from smaller, closer, more frequent earthquakes in the magnitude range (5 ≦ M ≦ 7) rather than from large San Andreas ruptures, whatever their likelihood.

scholarly journals THE BIRCH CREEK CANIDS AND DOGS AS TRANSPORT LABOR IN THE INTERMOUNTAIN WEST

2019 ◽  
Vol 84 (1) ◽  
pp. 88-106 ◽  
Author(s):  
Martin H. Welker ◽  
David A. Byers
Keyword(s):  
Native American ◽  
Body Mass ◽  
Great Basin ◽  
Great Plains ◽  
Canis Familiaris ◽  
Domestic Dogs ◽  
Intermountain West ◽  
Morphometric Data

Historically, domestic dogs(Canis familiaris)have been documented as central features of Intermountain West and Great Plains Native American camps. Some of these dogs were bred specifically for largeness and stamina to haultravoisand to carry pannier-style packs. Ethnographic accounts frequently highlight the importance of dogs in moving through the Intermountain West and the plains, reporting loads as heavy as 45 kg (100 lbs). We calculated body mass from skeletal morphometric data and used these to estimate prehistoric and historic dog load capacities for travois and pannier-style packs in the Intermountain West, Great Plains, and Great Basin. Specimens of large dogs recovered from sites in the Birch Creek Valley in Idaho and on the Great Plains indicate the animals could carry weights comparable to ethnographically recorded loads. Further, direct dating of the Birch Creek dog specimens indicated that dogs of this size have been present in the Intermountain West for more than 3,000 years. These data have important implications for our understanding of prehistoric mobility in the Intermountain West and the plains and suggest that the use of dogs in transporting cargo may have begun as early as 5,000 years ago.

The 1922 Peninsula Malaysia Earthquakes: Rare Intraplate Seismicity within the Sundaland Block in Southeast Asia

2020 ◽  
Vol 91 (5) ◽  
pp. 2531-2545 ◽  
Author(s):  
Stacey Servito Martin ◽  
Yu Wang ◽  
Muzli Muzli ◽  
Shengji Wei
Keyword(s):  
Seismic Hazard ◽  
Southeast Asia ◽  
Historical Earthquakes ◽  
Historical Seismicity ◽  
Point Of View ◽  
Malay Peninsula ◽  
Building Stock ◽  
Period Effects ◽  
Need To Evaluate ◽  
The Impact

Abstract Seismic hazard in the southern Malay Peninsula located within the Sundaland block in Southeast Asia is poorly understood. The paucity of historical earthquakes and low-magnitude instrumented seismicity has led to the assumption that this region is largely aseismic. We question this point of view by reassessing historical seismicity in this region and, in particular, a pair of moderate earthquakes in the 1920s. The first of these struck on 31 January 1922 at ≈9:10  a.m. local time (LT) for which we estimate an intensity magnitude (MI) ≈5.4, and for the second earthquake on 7 February 1922 at ≈12:15  p.m. LT, we estimate MI≈5.0. We also identify at least 34 felt earthquakes between 1803 and 1950 that were potentially local within the Sundaland block. These include a very widely felt shock (or set of shocks) on 26 June 1874 that was felt in parts of Borneo, Java, and Sumatra. The discovery of these earthquakes challenges the tectonic stability of the Malay Peninsula and the stable interior of the Sundaland block. The record of historical seismicity in this region relies heavily on European sources, and we recommend locating and consulting indigenous sources to improve the current understanding of regional seismic hazard. We also underscore the need to evaluate the impact of ground motions from rare local earthquakes on the extant building stock and on transportation infrastructure that are otherwise relatively immune to the long-period effects of distant earthquakes commonly felt in the Malay Peninsula.

scholarly journals Moisture Pathways into the U.S. Intermountain West Associated with Heavy Winter Precipitation Events*

2015 ◽  
Vol 16 (3) ◽  
pp. 1184-1206 ◽  
Author(s):  
Michael A. Alexander ◽  
James D. Scott ◽  
Dustin Swales ◽  
Mimi Hughes ◽  
Kelly Mahoney ◽  
...  
Keyword(s):  
Sierra Nevada ◽  
Heavy Precipitation ◽  
Empirical Orthogonal Functions ◽  
Water Vapor Transport ◽  
Intermountain West ◽  
Orthogonal Functions ◽  
Back Trajectories ◽  
Synoptic Conditions ◽  
The U.S ◽  
Precipitation Events

Abstract Two methods were used to identify the paths of moisture transport that reach the U.S. Intermountain West (IMW) during heavy precipitation events in winter. In the first, the top 150 precipitation events at stations located within six regions in the IMW were identified, and then back trajectories were initiated at 6-h intervals on those days at the four Climate Forecast System Reanalysis grid points nearest the stations. The second method identified the leading patterns of integrated water vapor transport (IVT) using the three leading empirical orthogonal functions of IVT over land that were first normalized by the local standard deviation. The top 1% of the associated 6-hourly time series was used to construct composites of IVT, atmospheric circulation, and precipitation. The results from both methods indicate that moisture originating from the Pacific that leads to extreme precipitation in the IMW during winter takes distinct pathways and is influenced by gaps in the Cascades (Oregon–Washington), the Sierra Nevada (California), and Peninsular Ranges (from Southern California through Baja California). The moisture transported along these routes appears to be the primary source for heavy precipitation for the mountain ranges in the IMW. The synoptic conditions associated with the dominant IVT patterns include a trough–ridge couplet at 500 hPa, with the trough located northwest of the ridge where the associated circulation funnels moisture from the west-southwest through the mountain gaps and into the IMW.

scholarly journals Neo-deterministic seismic hazard maps of Kosovo

2021 ◽  
Author(s):  
Enrico Brandmayr ◽  
Vaccari Franco ◽  
Romanelli Fabio ◽  
Vlahovic Gordana ◽  
Panza Giuliano Francesco
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Seismic Hazard Assessment ◽  
Active Regions ◽  
Earthquake Hazard ◽  
Earthquake Ground Motion ◽  
Hazard Maps ◽  
Source Information ◽  
Deterministic Seismic Hazard ◽  
Traditional Construction

Kosovo is one of the most seismically active regions in Europe, lying within the Alpine-Mediterranean tectonic belt. Historical records for the region show several catastrophic earthquakes with epicentral intensity IX (MCS). However, due to Kosovo’s high population density, high prevalence of traditional construction, and insufficient enforcement of building codes, Kosovo is vulnerable to earthquake damage. In this study, we present earthquake hazard maps for bedrock conditions in Kosovo based on the well-known Neo-deterministic Seismic Hazard Assessment (NDSHA) method. NDSHA relies upon the fundamental physics of wave generation and propagation in complex geologic structures to generate realistic time series, used as input for the computation of several ground motion parameters, integrating the available knowledge of seismic history, seismogenic zones and morphostructural nodes. In accordance with continuum mechanics, the tensor nature of earthquake ground motion is preserved, producing realistic signals using structural models obtained by tomographic inversion and earthquake source information readily available in literature. Our maps are generally consistent with the observed intensity IX (MCS) and suggest that, in some instances, intensity X could be reached.

From National to Transnational Seismic Monitoring Products and Services in the Republic of Bulgaria, Republic of Moldova, Romania, and Ukraine

2021 ◽  
Author(s):  
Alexandru Mărmureanu ◽  
Constantin Ionescu ◽  
Bogdan Grecu ◽  
Dragos Toma-Danila ◽  
Alexandru Tiganescu ◽  
...  
Keyword(s):  
Risk Mitigation ◽  
Seismic Monitoring ◽  
Current Status ◽  
Waveform Data ◽  
Strong Earthquakes ◽  
Crustal Earthquakes ◽  
Seismic Waveform ◽  
The Republic ◽  
Seismic Networks ◽  
Research Facilities

Abstract The aim of this article is to analyze the background, current status, and outlook of seismic monitoring products and services in Bulgaria, Moldova, Romania, and Ukraine. These countries manage seismic networks that contribute to the European Integrated Data Archive node in the framework of the Observatories and Research Facilities for European Seismology, which represents a collaborative effort in coordinating observational seismology across the European region through the collection, archiving, and dissemination of seismic waveform data, metadata, and related products. All of the aforementioned countries share a common threat: strong earthquakes occurring in the Vrancea area located in central-eastern Romania at intermediate depths (usually in the 60–180 km interval). Events such as the ones on 10 November 1940 and 4 March 1977 generated high damage in Romania, northern Bulgaria, and Moldova. In addition to Vrancea, crustal earthquakes in areas such as Shabla or Dulovo can lead to cross-border damage. Therefore, understanding the way national seismic networks are distributed, how they cooperate, and the products and services that they provide in (near) real time and their terms is of significant interest in the context of necessary hazard harmonization and joint emergency intervention and risk mitigation actions.

Seismotectonic Snapshots: The 18 March 2020 Mw 5.7 Magna, 31 March 2020 Mw 6.5 Stanley, and 15 May 2020 Mw 6.5 Monte Cristo Intermountain West Earthquakes

2021 ◽  
Author(s):  
Steven G. Wesnousky
Keyword(s):  
Active Faults ◽  
Relative Size ◽  
Fault System ◽  
Intermountain West ◽  
Surface Rupture ◽  
Slip Mechanism ◽  
Walker Lane ◽  
Earthquake Ruptures ◽  
Seismic Networks ◽  
Broad Region

Abstract Seismological characteristics of the 18 March 2020 Mw 5.7 Magna, 31 March 2020 Mw 6.5 Stanley, and 15 May 2020 Mw 6.5 Monte Cristo Intermountain West earthquakes are largely consistent with expectations arising from observations accumulated over the ∼40  yr since implementation and subsequent growth of seismic networks in the broad region. Each occurred within a zone of relatively elevated seismicity, active faults, and geodetically observed strain accumulation. Aftershock distributions in each are confined primarily to depths of <15  km, and the total number of aftershocks correlates with the relative size of the events. In each case, the number per day decays exponentially in the days following the mainshock. None of the mainshocks was preceded by a foreshock sequence that delivered a plausible warning of the impending earthquakes. With respect to tectonics, each earthquake brings new insights. The Stanley and Monte Cristo earthquakes are at the margins of geodetically defined regions of right-lateral transtension, though the pattern of faulting in each region is markedly different. The strike-slip mechanism of the Stanley earthquake stands in contrast to the zone of normal major range bounding faults and historical earthquake ruptures that characterize the region in which it occurred and is the first relatively well instrumented event to show a rupture extending northward through the Trans-Challis fault system. The Magna event has been interpreted to represent low-angle normal slip near the base of a listric Wasatch range bounding fault (Pang et al., 2020). The east-striking left-lateral Monte Cristo earthquake within the Walker Lane is in contrast to the major northwest-striking right-lateral faults that dominate the area, though predictable from prior regional mapping. Surface rupture reportedly accompanied only the Monte Cristo earthquake, though its trace does not clearly follow the zone of aftershocks.

Seismic hazard analysis: a comparative study

2006 ◽  
Vol 33 (9) ◽  
pp. 1156-1171 ◽  
Author(s):  
H P Hong ◽  
K Goda ◽  
A G Davenport
Keyword(s):  
Seismic Hazard ◽  
Seismic Hazard Assessment ◽  
Historical Seismicity ◽  
Hazard Maps ◽  
Uniform Hazard Spectra ◽  
Attenuation Relations ◽  
Seismic Hazard Maps ◽  
Cell Method ◽  
Thiessen Polygon ◽  
The Impact

The quantitative seismic hazard maps for the 1970s National Building Code of Canada were evaluated using the Davenport–Milne method. The Cornell–McGuire method is employed to develop recent seismic hazard maps of Canada. These methods incorporate the information on seismicity, magnitude-recurrence relations, and ground motion (or response) attenuation relations. The former preserves and depends completely on details of the historical seismicity; the latter smoothes the irregular spatial occurrence pattern of the historical seismicity into seismic source zones. Further, the Epicentral Cell method, which attempts to incorporate the preserving and smoothing aspect of these methods, has been developed. However, the impact of the adopted assumptions on the estimated quantitative seismic hazard has not been investigated. This study provides a comparative seismic hazard assessment using the above-mentioned methods and simulation-based algorithms. The analysis results show that overall the Davenport–Milne method gives quasi-circular seismic hazard contours near significant historical events, and the Cornell–McGuire method smoothes the transition of contours. The Epicentral Cell method provides estimates approximately within the former and the latter. Key words: epicentral cell method, probability, seismic hazard, Thiessen polygon, Voronoi, uniform hazard spectra.

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