The Intensity of Ground Motions from Induced Earthquakes with Implications for Damage Potential

2020 ◽  
Vol 110 (5) ◽  
pp. 2366-2379 ◽  
Author(s):  
Gail M. Atkinson
Keyword(s):  
Ground Motions ◽  
Damage Threshold ◽  
Western Canada ◽  
Induced Earthquakes ◽  
Damage Potential ◽  
Tectonic Events ◽  
Significant Damage ◽  
The Moment ◽  
Natural Earthquakes ◽  
The U.S

ABSTRACT The damage potential of induced earthquakes is compared to that of natural tectonic events, considering recent instrumental data and felt records from events of M 3.5–5.8 (in which M is the moment magnitude). Ground motions are mutually consistent at close distances (<30  km) for natural earthquakes in California, induced earthquakes in Oklahoma, and induced earthquakes in western Canada, despite differences in the dominant processes that trigger the events. Recorded peak ground motions may exceed the damage threshold for induced events of M∼4.0 within ∼5  km of the hypocenter; events of M≥4.5 are inferred to have significant damage potential within 5 km and may be damaging to greater distances. Felt and damage effects in Oklahoma, as reported on the U.S. Geological Survey’s online “Did You Feel It?” system, show that the damage threshold (modified Mercalli intensity [MMI] = 6) is commonly exceeded for events of M∼4.5 at close distances (<10  km) and that significant damage effects (MMI=7) are observed for M>4.8 events within 10 km.

The Norris Lake Earthquake Swarm of June Through September, 1993; Preliminary Findings

1994 ◽  
Vol 65 (2) ◽  
pp. 167-171 ◽  
Author(s):  
L.T. Long ◽  
A. Kocaoglu ◽  
R. Hawman ◽  
P.J.W. Gore
Keyword(s):  
Earthquake Swarm ◽  
Building Stone ◽  
Aftershock Sequence ◽  
Average Depth ◽  
Induced Earthquakes ◽  
Epicentral Area ◽  
Event Recorder ◽  
Significant Damage ◽  
The 1950S ◽  
Recreational Lake

Abstract During the summer of 1993, the residents in the Norris Lake community, Lithonia, Georgia, were bothered by an incessant swarm of earthquakes. The largest, a magnitude 2.7 on September 23, showed a normal aftershock decay and occurred after the main swarm. Over 10,000 earthquakes have been detected, of which perhaps 500 were felt. The earthquakes began June 8, 1993, with a 5-day swarm. The residents, accustomed to quarry explosions, suspected the quarries of irregular activities. To locate the source of the events, a visual recorder and a digital event recorder were placed in the epicentral area. Ten to 20 events were detected per day for the next three weeks. The swarm then escalated to a peak of over 100 per day by August 15, 1993. Activity following the peak died down to about 10 events per day. The magnitude 2.7 event of September 23 was followed by a normal aftershock sequence. The larger events were felt with intensity V within 2 km of their epicenter, and noticed (intensity II) to a distance of 15 km. Some incidents of cracked wallboard and foundations have been reported, but no significant damage has been documented. Preliminary locations, based on data from digital event recorders, suggest an average depth of 1.0 km. The hypocenters are in the Lithonia gneiss, a massive migmatite resistant to weathering and used locally as a building stone. The epicenters are 1 to 2 km south-southwest of the Norris Lake Community. The cause of the seismicity is not yet known. The earthquakes are characteristic of reservoir-induced earthquakes; however, Norris Lake is a small (96 acres), 2 to 5m deep recreational lake which has existed since the 1950s.

Effects of Fling Step and Forward Directivity on Seismic Response of Buildings

2006 ◽  
Vol 22 (2) ◽  
pp. 367-390 ◽  
Author(s):  
Erol Kalkan ◽  
Sashi K. Kunnath
Keyword(s):  
Seismic Response ◽  
Ground Motions ◽  
High Amplitude ◽  
Moment Frames ◽  
Steel Moment Frames ◽  
Damage Potential ◽  
Near Fault ◽  
Forward Directivity ◽  
Fling Step ◽  
Far Fault

This paper investigates the consequences of well-known characteristics of near-fault ground motions on the seismic response of steel moment frames. Additionally, idealized pulses are utilized in a separate study to gain further insight into the effects of high-amplitude pulses on structural demands. Simple input pulses were also synthesized to simulate artificial fling-step effects in ground motions originally having forward directivity. Findings from the study reveal that median maximum demands and the dispersion in the peak values were higher for near-fault records than far-fault motions. The arrival of the velocity pulse in a near-fault record causes the structure to dissipate considerable input energy in relatively few plastic cycles, whereas cumulative effects from increased cyclic demands are more pronounced in far-fault records. For pulse-type input, the maximum demand is a function of the ratio of the pulse period to the fundamental period of the structure. Records with fling effects were found to excite systems primarily in their fundamental mode while waveforms with forward directivity in the absence of fling caused higher modes to be activated. It is concluded that the acceleration and velocity spectra, when examined collectively, can be utilized to reasonably assess the damage potential of near-fault records.

Ground Motions from Induced Earthquakes in Oklahoma and Kansas

2018 ◽  
Vol 90 (1) ◽  
pp. 160-170 ◽  
Author(s):  
Morgan P. Moschetti ◽  
Eric M. Thompson ◽  
Peter M. Powers ◽  
Susan M. Hoover ◽  
Daniel E. McNamara
Keyword(s):  
Ground Motions ◽  
Induced Earthquakes

Trioza erytreae (African citrus psyllid).

2021 ◽  
Author(s):  
Esther Arengo
Keyword(s):  
Middle East ◽  
Citrus Greening ◽  
Damage Potential ◽  
Quarantine Pest ◽  
Mediterranean Countries ◽  
Significant Damage ◽  
The Family ◽  
Citrus Huanglongbing ◽  
African Form ◽  
Wild Hosts

Abstract The invasive African psyllid, Trioza erytrea, transmits the causal agent of the African form of citrus huanglongbing (greening) disease, Liberibacter africanum, a very destructive disease of citrus plants. It does this under natural conditions in Africa and the Middle East, and has been shown experimentally to transmit the Asian form, Liberibacter asiaticum. The psyllid itself severely distorts leaves, which become stunted and galled. T. erytreae affects species in the family Rutaceae, occurring on wild hosts as well as on Citrus species. T. erytreae is listed as an A1 quarantine pest by EPPO (OEPP/EPPO, 1988) and is also a quarantine pest for CPPC and OIRSA. The importation of plants for planting and cut branches of citrus from countries where either citrus greening bacterium or either of its vectors occur has been prohibited (OEPP/EPPO, 1990). T. erytreae occurs in Africa and parts of the Middle East but could probably establish and spread in Mediterranean countries without difficulty. Besides its role in citrus greening, the psyllid has itself significant damage potential.

Reframing Solidarity: Company Magazine as Family Album

2018 ◽  
Vol 3 (1) ◽  
pp. 50-67
Author(s):  
Courtney Maloney
Keyword(s):  
Twentieth Century ◽  
Middle Class ◽  
Labor Unions ◽  
Union Membership ◽  
Cultural Dimension ◽  
Economic Factors ◽  
Standards Of Living ◽  
Concomitant Reduction ◽  
The Moment ◽  
The U.S

We are witnessing a time of shrinking labor unions across the globe. Among member states of the Organisation for Economic Co-operation and Development, rates of union membership have declined from 30% in 1985 to 20% today (McCarthy 2017). In the U.S., the current rate is just 10.7% (Yadoo 2018). We have seen along with this the concomitant reduction in working-class and middle-class standards of living. Technological, political, and economic factors have impacted this change, but there is a cultural dimension to it as well. From the moment industrial unions in the U.S. gained power, corporations began to counter workingclass solidarity with alternative narratives that emphasized individualism, domesticity, and leisure. This article illuminates such efforts with a reading of one particularly sophisticated example from the mid-twentieth century, in which a steel corporation’s company magazine used workers’ own participation and self-representations in an effort to reorient notions of solidarity toward an identification with the corporation as family.

scholarly journals Analysis of strong-motion data of the 1990 Eastern Sicily earthquake

1995 ◽  
Vol 38 (2) ◽  
Author(s):  
M. Di Bona ◽  
M. Cocco ◽  
A. Rovelli ◽  
R. Berardi ◽  
E. Boschi
Keyword(s):  
Frequency Band ◽  
Stress Drop ◽  
Seismic Moment ◽  
Ground Motions ◽  
Broad Band ◽  
Strong Motion ◽  
Moment Magnitude ◽  
Corner Frequency ◽  
Local Magnitude ◽  
The Moment

The strong motion accelerograms recorded during the 1990 Eastern Sicily earthquake have been analyzed to investigate source and attenuation parameters. Peak ground motions (peak acceleration, velocity and displacement) overestimate the values predicted by the empirical scaling law proposed for other Italian earthquakes, suggesting that local site response and propagation path effects play an important role in interpreting the observed time histories. The local magnitude, computed from the strong motion accelerograms by synthesizing the Wood-Anderson response, is ML = 5.9, that is sensibly larger than the local magnitude estimated at regional distances from broad-band seismograms (ML = 5.4). The standard omega-square source spectral model seems to be inadequate to describe the observed spectra over the entire frequency band from 0.2 to 20 Hz. The seismic moment estimated from the strong motion accelerogram recorded at the closest rock site (Sortino) is Mo = 0.8 x 1024 dyne.cm, that is roughly 4.5 times lower than the value estimated at regional distances (Mo = 3.7 x 1024 dyne.cm) from broad-band seismograms. The corner frequency estimated from the accelera- tion spectra i.5 J; = 1.3 Hz, that is close to the inverse of the dUl.ation of displacement pulses at the two closest recording sites. This value of corner tì.equency and the two values of seismic moment yield a Brune stress drop larger than 500 bars. However, a corner frequency value off; = 0.6 Hz and the seismic moment resulting from regional data allows the acceleration spectra to be reproduced on the entire available frequency band yielding to a Brune stress drop of 210 bars. The ambiguity on the corner frequency value associated to this earthquake is due to the limited frequency bandwidth available on the strong motion recordil1gs. Assuming the seismic moment estimated at regional distances from broad-band data, the moment magnitude for this earthquake is 5.7. The higher local magnitude (5.9) compared with the moment magnitude (5.7) is due to the weak regional attenuation. Beside this, site amplifications due to surface geology have produced the highest peak ground motions among those observed at the strong motion sites.

The Compromise That Made the Republic and the Nation’s First Statistical Race

2013 ◽  
Author(s):  
Kenneth Prewitt
Keyword(s):  
United States ◽  
Public Policy ◽  
Affirmative Action ◽  
Social Science ◽  
American History ◽  
Starting Point ◽  
The Creation ◽  
The Republic ◽  
The Moment ◽  
The U.S

This chapter demonstrates how assumptions of racial superiority and inferiority tightly bound together statistical races, social science, and public policy. The starting point of this is constitutional language. The U.S. Constitution required a census of the white, the black, and the red races. Without this statistical compromise there would not have been a United States as it is today. In the early censuses slaves were counted as three-fifths of a person, a ratio demanded by slaveholder interests as the price of joining the Union. A deep policy disagreement at the moment of founding the nation was resolved in the creation of a statistical race. Later in American history the reverse frequently occurred. Specific policies—affirmative action, for example—took the shape they did because the statistical races were already at hand.

‘We Are Where We Are’

2019 ◽  
pp. 219-248
Author(s):  
Sinéad Moynihan
Keyword(s):  
Economic Model ◽  
Economic Recovery ◽  
Historical Novels ◽  
Celtic Tiger ◽  
Ellis Island ◽  
Transatlantic Relationship ◽  
Feminine Self ◽  
The Moment ◽  
The U.S

Arguing that return emigration and the figure of the returnee have proven central to discourses of Irish economic recovery, the coda puts Colm Tóibín’s Brooklyn (2009) in conversation with Kate Kerrigan’s Ellis Island (2009), situating both historical novels emphatically within the moment of their composition rather than those periods during which they are set (1950s and 1920s). It contends that they must be read in the context of wider Irish discourses of self-analysis that accompanied the collapse of the Celtic Tiger economy, discourses which troubled the historical construction of the Irish/U.S. transatlantic relationship in oppositional terms by suggesting that boom-time Ireland had, in fact, become the U.S. Emphasising both novels’ interest in forms of feminine self-fashioning, labour and enterprise that are evocative of the ways in which the Celtic Tiger was, itself, constructed as feminine, the coda argues that the novels deploy the motifs of emigration and return in order to explore and, to varying degrees, critique the neoliberal economic model celebrated during the boom years.

Conclusion

2020 ◽  
pp. 248-268
Author(s):  
Craig Allen
Keyword(s):  
Digital Media ◽  
Public Awareness ◽  
50Th Anniversary ◽  
Formative Period ◽  
Spanish Language ◽  
Third Generation ◽  
Traditional Media ◽  
History Of ◽  
The Moment ◽  
The U.S

Univision celebrates the 50th anniversary of Spanish-language television in 2012. The moment is occasioned by the first widespread public awareness of Spanish-language television and the large U.S. population is reaches and impacts. The first extensive criticism ensues. Conservative politicians attack the endeavor for dividing traditional U.S. society and for an alleged liberal bias. Believing it impedes Latinos’ success in the U.S., Governor Arnold Schwarzenegger urges them to turn off the Spanish TV set. Closer observers complain that banal and distant foreign programming fails to address the interests and needs of U.S. Latinos. They scorn Univision and Telemundo for reconfiguring U.S. Latinos of diverse nationalities into a “Pan Latinidad.” Many of the criticisms are not supported by the endeavor’s history. Yet at the time of the anniversary, more pertinent than the criticisms are unresolved questions. Latinos’ increasing preference for interactive digital media is fragmenting the audiences that Univision and Telemundo as traditional media once had amassed. Slowly foreseen is potentially the largest challenge, that the preponderance of younger “third generation” Latinos increasingly are inclined to speak English. Regardless of the future, the history of Spanish-language television will remain important as a light on a “television age” that is essential to understanding a U.S. that changed during a highly formative period in the nation’s history.

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