scholarly journals Variations in Earth's 1D viscosity structure in different tectonic regimes

2022 ◽  
Author(s):  
Anthony Osei Tutu ◽  
Christopher Harig
Keyword(s):  
Transition Zone ◽  
Pacific Region ◽  
Atlantic Region ◽  
Long Wavelength ◽  
Compositional Evolution ◽  
Mantle Viscosity ◽  
The Pacific ◽  
Spectral Localization ◽  
Subducted Oceanic Crust ◽  
Strong Transition

Earth’s long-wavelength geoid provides insights into the thermal, structural, and compositional evolution of the mantle. Historically, most estimates of mantle viscosity using the long-wavelength geoid have considered radial variations with depth in a symmetric Earth. Global estimates of this kind suggest an increase in viscosity from the upper mantle to lower mantle of roughly 2 -- 3 orders of magnitude. Using a spatio-spectral localization technique with the geoid, here we estimate a series of locally constrained viscosity-depth profiles covering two unique regions, the Pacific and Atlantic hemispheres, which show distinct rheological properties. The Pacific region exhibits the conventional Earth's 1D rheology with a factor of roughly 80-100 increase in viscosity occurring at transition zone depths (400 - 800 km). The Atlantic region in contrast does not show significant viscosity jumps with depth, and instead has a near uniform viscosity in the top 1000~km. The inferred viscosity variations between our two regions could be due to the prevalence of present-day subduction in the Pacific and the infrequence of slabs in the Atlantic, combined with a possible hydrated transition zone and mid-mantle of the Atlantic region by ancient subduction during recent supercontinent cycles. Rigid slab material within the top 800 km, with about 90\% Majoritic garnet in the form of subducted oceanic crust, coupled with unique regional mantle structures, may be generating a strong transition zone viscosity interface for the Pacific region. These effective lateral variations in mantle viscosity could play a role in the observed deformation differences between the Pacific and Atlantic hemispheres.

scholarly journals THE AMERICAN SPECIES OF PERINEURA

1895 ◽  
Vol 27 (1) ◽  
pp. 7-8 ◽  
Author(s):  
Alex. D. Macgillivray
Keyword(s):  
North America ◽  
Pacific Region ◽  
Atlantic Region ◽  
The Pacific

The Abbe Provancher described two species of Synairema from North America, one from the Atlantic region and one from the pacific region; a second species, from the Pacific region, isdescribed below. The genus Synairema is considered as a synonym of perineura, by Kirby.

Vietnam in the Indo-Pacific Region: Perception, Position and Perspectives

2021 ◽  
pp. 097492842110050
Author(s):  
Nguyen Le Thy Thuong ◽  
Nguyen Thi Oanh
Keyword(s):  
Swot Analysis ◽  
Geographic Area ◽  
Common Interest ◽  
Pacific Region ◽  
Analysis Model ◽  
Common Space ◽  
The Pacific ◽  
The World ◽  
State Behaviour ◽  
Asian Pacific

The Indo-Pacific region is an area adjacent to some oceans and the gateway that connects the great power and small countries to the world; this region is always considered by Vietnam as a key strategic geographic area, having direct impacts on national security, position and its role in this region. While big powers have different perceptions to the Indo-Pacific region, as a country occupying an important geographic position in the Pacific region, Vietnam shares a common vision of an open and rule-based area, and a common interest in maintaining peace, stability and prosperity as well as building a common space for coexistence and development with the belief that the Indo-Asian-Pacific is large enough for every nation to grow and prosper. This article finds out that recent changes in the Indo-Pacific region in geopolitics, economics, security and national defence have made many countries, including Vietnam, to redefine their global and regional policies to refresh their strategic perceptions. Vietnam has its own perception, position, approach and national orientations, which is shaping its state behaviour and perspectives in this geopolitical vibrant Indo-Pacific region. Besides, this article uses the SWOT analysis model to determine the challenges, strengths and weaknesses of Vietnam in the Indo-Pacific region. Moreover, while the future of the Indo-Pacific in a post-COVID-19 pandemic world remains filled with uncertainty and economic challenges, the crisis also presents an opportunity for Vietnam to re-evaluate its position. Today, Vietnam always maintains its foreign policy of independence, self-reliance, multilateralism and diversification of international relations, which attaches great importance to enhancing multi-faceted cooperation with countries in the Indo-Pacific region. Thus, with its own perception and geostrategic advantage, Vietnam—a developing country in the region and in the world with relatively stable economic growth, pursuing rules and order will be a positive factor for a stable, peaceful and prosperous development in the region.

scholarly journals The characteristics of behaviour change interventions used among Pacific people: a systematic search and narrative synthesis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Amio Matenga-Ikihele ◽  
Judith McCool ◽  
Rosie Dobson ◽  
Fuafiva Fa’alau ◽  
Robyn Whittaker
Keyword(s):  
United States ◽  
Social Support ◽  
New Zealand ◽  
Behaviour Change ◽  
Health Behaviour ◽  
Narrative Synthesis ◽  
Pacific Region ◽  
Behaviour Change Interventions ◽  
Pacific People ◽  
The Pacific

Abstract Background Pacific people living in New Zealand, Australia, United States, and the Pacific region continue to experience a disproportionately high burden of long-term conditions, making culturally contextualised behaviour change interventions a priority. The primary aim of this study was to describe the characteristics of behaviour change interventions designed to improve health and effect health behaviour change among Pacific people. Methods Electronic searches were carried out on OVID Medline, PsycINFO, PubMed, Embase and SCOPUS databases (initial search January 2019 and updated in January 2020) for studies describing an intervention designed to change health behaviour(s) among Pacific people. Titles and abstracts of 5699 papers were screened; 201 papers were then independently assessed. A review of full text was carried out by three of the authors resulting in 208 being included in the final review. Twenty-seven studies were included, published in six countries between 1996 and 2020. Results Important characteristics in the interventions included meaningful partnerships with Pacific communities using community-based participatory research and ensuring interventions were culturally anchored and centred on collectivism using family or social support. Most interventions used social cognitive theory, followed by popular behaviour change techniques instruction on how to perform a behaviour and social support (unspecified). Negotiating the spaces between Eurocentric behaviour change constructs and Pacific worldviews was simplified using Pacific facilitators and talanoa. This relational approach provided an essential link between academia and Pacific communities. Conclusions This systematic search and narrative synthesis provides new and important insights into potential elements and components when designing behaviour change interventions for Pacific people. The paucity of literature available outside of the United States highlights further research is required to reflect Pacific communities living in New Zealand, Australia, and the Pacific region. Future research needs to invest in building research capacity within Pacific communities, centering self-determining research agendas and findings to be led and owned by Pacific communities.

The Pacific region

1993 ◽  
Vol 39 (1-2) ◽  
pp. 124-133
Author(s):  
Kaminieli Tagica
Keyword(s):  
Pacific Region ◽  
The Pacific
Sign in / Sign up

Export Citation Format

Share Document