scholarly journals Geophysical analysis of the 30 July 1972 Sitka, Alaska, earthquake sequence

Geosphere ◽  
2020 ◽  
Vol 16 (3) ◽  
pp. 712-722
Author(s):  
Juan A. Ochoa Chavez ◽  
Diane I. Doser
Keyword(s):  
North American ◽  
Rock Type ◽  
Seismic Hazard Assessment ◽  
Historical Event ◽  
Structural Variations ◽  
The Pacific ◽  
Phase Data ◽  
Near Future ◽  
Transform Boundary ◽  
Alaska Earthquake

Abstract The 1972 Mw 7.6 Sitka earthquake is the largest historical event along the southeastern Alaska portion of the strike-slip Queen Charlotte fault, the transform boundary between the Pacific and North American plates. The fault is one of the fastest moving transform boundaries in the world, having accumulated enough slip since 1972 to produce an event of comparable size in the near future. Thus, understanding the controls on the rupture process of the 1972 mainshock is important for seismic hazard assessment in Alaska. Following the mainshock, the U.S. Geological Survey installed a network of portable seismographs that recorded over 200 aftershocks. These locations were never published, and the original seismograms and digital phase data were misplaced. However, we were able to scan paper copies of the phase data, convert the data to digital form, and successfully relocate 87 aftershocks. The relocations show two clusters of aftershocks along the Queen Charlotte fault, one ∼40 km north of the mainshock epicenter and the other just south of the mainshock, both regions adjacent to portions of the fault that experienced maximum moment release in 1972. Many of the northern aftershocks locate east of the Queen Charlotte fault. This pattern is similar to aftershocks observed in the 2013 Mw = 7.5 Craig, Alaska earthquake. Recent and pre-1971 (1925–1970) seismicity indicates that the regions where aftershocks clustered remained active through time. Gravity, magnetic, and bathymetric anomalies suggest that the structural variations in both the Pacific and North American plates (e.g., age, density, rock type, and thickness) play roles in rupture nucleation and termination along the northern Queen Charlotte fault.

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 “We are the People”: The Holodomor and North American-Ukrainian Diasporic Memory in Marsha Forchuk Skrypuch’s “Enough”

2018 ◽  
Vol 7 ◽  
pp. 49-71
Author(s):  
Anastasia Ulanowicz
Keyword(s):  
United States ◽  
Fairy Tales ◽  
North American ◽  
Cultural Memory ◽  
Fairy Tale ◽  
Picture Book ◽  
The United States ◽  
Historical Event ◽  
Young Readers ◽  
The People

“We are the People”: The Holodomor and North American-Ukrainian Diasporic Memory in Marsha Forchuk Skrypuch’s Enough. Although the Holodomor — the Ukrainian famine of 1932–1933 — has played a major role in the cultural memory of Ukrainian diasporic communities in the United States and Canada, relatively few North American children’s books directly represent this traumatic historical event. One exception, however, is Marsha Forchuk Skrypuch’s and Michael Martchenko’s picture book, Enough 2000, which adapts a traditional Ukrainian folktale in order to introduce young readers to the historical and polit­ical circumstances in which this artificial famine occurred. By drawing on what scholar Jack Zipes has identified as the “subversive potential” of fairy tales, Skrypuch and Martchenko critique the ironies and injustices that undergirded Soviet forced collectivization and Stalinist famine policy. Additionally, they explicitly set a portion of their fairy tale adaptation in Canada in order to gesture to the role played by the Holodomor in structuring diasporic memory and identity, especially in relation to post-Independ­ence era Ukraine.«Мы — народ»: Голодомор и североамериканско-украинская диаспорная память в книге Enough Марши Форчук Скрыпух. Несмотря на то, что Голодомор — голод в Украине 1932–1933 гoдов — сыграл важную роль в культурной памяти украинских диаспорных общин в Соеди­ненных Штатах и Канаде, относительно мало североамериканских детских книг описывает это травматическое событие. Важное место в этом контексте является книга Марши Форчук Скры­пух и Майкла Мартченко «Достаточно» 2000, которая адаптирует традиционную украинскую сказку для того, чтобы познакомить молодых читателей с историческими и политическими обстоятельствами этого искусственного голода. Опираясь на то, что ученый Джек Зайпс назвал «подрывным потенциалом» сказок, Скрыпух и Мартченко критикуют иронию и несправедли­вость советской принудительной коллективизации и политики сталинского голода. Кроме того, они установили часть своей сказочной адаптации в Канаде, чтобы показать роль Голодомора в структурировании диаспорной памяти и самобытности, и связи последних с независимой Украиной.

scholarly journals PERANG PASIFIK DI PULAU MOROTAI: Rekonstruksi Infrastruktur dan Strategi Perang

2018 ◽  
Vol 16 (1) ◽  
pp. 69
Author(s):  
Wuri Handoko ◽  
Arsthen P. Godlief ◽  
Cheviano E. Alputila
Keyword(s):  
Aerial Photographs ◽  
Historical Event ◽  
Archaeological Survey ◽  
Pacific War ◽  
Major Powers ◽  
Archaeological Data ◽  
The Pacific ◽  
The World ◽  
Local Residents ◽  
Military Archaeology

Pacific war in Morotai is an important historical event in Indonesia as well as in the world. The Pacific war involving two major powers, the Allies and Japan, left a trail of archaeological studies examined to record a very important historical event in the Pacific region of Morotai Island. Based on the concept of military archaeology, this study uses archaeological data to reconstruct infrastructure and allied strategies in combat against Japan. Investigation of these remains proceeded through studying textual and photographic records on the Allies' occupation of Morotai Island, and examination of modern-day aerial photographs of the terrain where the Allies built their infrastructure, followed by archaeological survey and through interviewing local residents to describe traces of the Pacific war infrastructure. The results explain that the preparation of good infrastructure by the allies is part of the war strategy, which determines the win for the allies against the Japanese.Perang pasifik di Morotai merupakan peristiwa sejarah yang penting di Indonesia dan juga di dunia. Perang Pasifik yang melibatkan dua kekuatan besar, Sekutu dan Jepang, meninggalkan jejak arkeologi peperangan yang dikaji untuk merekam peristiwa sejarah yang sangat penting di kawasan pasifik di Pulau Morotai. Berdasarkan konsep military archaeology, penelitian ini menggunakan data arkeologi untuk merekonstruksi infrastruktur dan strategi sekutu dalam pertempuran melawan Jepang. Investigasi arkeologi dilakukan dengan mempelajari catatan tekstual dan fotografis tentang pendudukan Pulau Morotai oleh Sekutu, dan pemeriksaan foto-foto udara modern di daerah Sekutu membangun infrastruktur, dan selanjutnya melakukan survei arkeologi dan wawancara penduduk setempat untuk menggambarkan jejak infrastrukutr perang pasifik. Hasil penelitian menjelaskan bahwa penyiapan insfrastruktur dengan baik oleh pihak sekutu merupakan bagian dari strategi perang, yang menentukan kemenangan bagi pihak sekutu dalam melawan Jepang.

Manifestation of the Pacific Decadal Oscillation in the stationary planetary waves activity

2021 ◽  
Author(s):  
Daria Sobaeva ◽  
Yulia Zyulyaeva ◽  
Sergey Gulev
Keyword(s):  
Pacific Decadal Oscillation ◽  
North American ◽  
Lower Stratosphere ◽  
El Nino ◽  
Planetary Waves ◽  
Positive Phase ◽  
Negative Phase ◽  
Middle Troposphere ◽  
The Pacific ◽  
The Tropics

<p>Strong quasi-decadal oscillations of the stratospheric polar vortex (SPV) intensity are in phase with the Pacific decadal oscillation (PDO). A stronger SPV is observed during the positive phase of the PDO, and during the negative phase, the intensity of the SPV is below the mean climate values. The SPV intensity anomalies, formed by the planetary waves and zonal mean flow interaction, lead to the weakening/intensification of the vortex.</p><p>This research aimed to obtain the differences in the characteristics and the spatial propagation pattern of the planetary waves in the middle troposphere and lower stratosphere during different PDO phases. We analyzed composite periods of years when the PDO index has extremely high and low values. Two periods were constructed for both positive and negative phases, the first consisting of years with El-Nino/La-Nina events and the second without prominent sea surface temperature anomalies in the tropics. </p><p>During the wintertime in the Northern Hemisphere (December-February), wave 2 with two ridges (Siberian and North American Highs) and two troughs (Icelandic and Aleutian Lows) dominates in the middle troposphere, along with wave 1 dominating in the lower stratosphere. In the middle troposphere, at the positive phase ​​of the PDO, the amplitude of wave 2 is higher than in years with negative values of the PDO index. The differences in the Aleutian Low and the North American High intensity between the two phases are significant at the 97.5% level. In the lower stratosphere, the wave amplitude is lower at the negative phase ​​of the PDO, but we can also talk about a slight shift of the wave phase to the east. The regions of the heavy rains in the tropics during El-Nino events are the planetary waves source. They propagate from low to high latitudes, which results in modifying the characteristics and locations of the intensification of the stationary planetary waves in mid-latitudes.</p>

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