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Sample records for volcano solomon islands

  1. Solomon Islands.

    PubMed

    1988-06-01

    The Solomon Islands, which form an archipelago in the Southwest Pacific about 1900 km northeast of Australia, are described. Included are brief descriptions about such points as geography, people, history, type of government, political conditions, economy, and foreign relations. In 1987 the population was 301,180 (49% under age 14); the annual growth rate was 3.67%. The infant mortality rate is 46/1000; the life expectancy, 54 years. Health conditions in the Solomons generally are adequate, and the country does not suffer from serious endemic diseases other than malaria, in both the vivax and falsiparum strains. Hospitals and pharmacies are limited to population centers and missions. PMID:12177986

  2. The petrogenesis of sodic island arc magmas at Savo volcano, Solomon Islands

    NASA Astrophysics Data System (ADS)

    Smith, D. J.; Petterson, M. G.; Saunders, A. D.; Millar, I. L.; Jenkin, G. R. T.; Toba, T.; Naden, J.; Cook, J. M.

    2009-12-01

    Savo, Solomon Islands, is a historically active volcano dominated by sodic, alkaline lavas, and pyroclastic rocks with up to 7.5 wt% Na2O, and high Sr, arc-like trace element chemistry. The suite is dominated by mugearites (plagioclase-clinopyroxene-magnetite ± amphibole ± olivine) and trachytes (plagioclase-amphibole-magnetite ± biotite). The presence of hydrous minerals (amphibole, biotite) indicates relatively wet magmas. In such melts, plagioclase is relatively unstable relative to iron oxides and ferromagnesian silicates; it is the latter minerals (particularly hornblende) that dominate cumulate nodules at Savo and drive the chemical differentiation of the suite, with a limited role for plagioclase. This is potentially occurring in a crustal “hot zone”, with major chemical differentiation occurring at depth. Batches of magma ascend periodically, where they are subject to decompression, water saturation and further cooling, resulting in closed-system crystallisation of plagioclase, and ultimately the production of sodic, crystal and feldspar-rich, high-Sr rocks. The sodic and hydrous nature of the parental magmas is interpreted to be the result of partial melting of metasomatised mantle, but radiogenic isotope data (Pb, Sr, Nd) cannot uniquely identify the source of the metasomatic agent.

  3. Exploring the "Sharkcano": Biogeochemical observations of the Kavachi submarine volcano (Solomon Islands) using simple, cost-effective methods.

    NASA Astrophysics Data System (ADS)

    Phillips, B. T.; Albert, S.; Carey, S.; DeCiccio, A.; Dunbabin, M.; Flinders, A. F.; Grinham, A. R.; Henning, B.; Howell, C.; Kelley, K. A.; Scott, J. J.

    2015-12-01

    Kavachi is a highly active undersea volcano located in the Western Province of the Solomon Islands, known for its frequent phreatomagmatic eruptions and ephemeral island-forming activity. The remote location of Kavachi and its explosive behavior has restricted scientific exploration of the volcano, limiting observations to surface imagery and peripheral water-column data. An expedition to Kavachi in January 2015 was timed with a rare lull in volcanic activity, allowing for observation of the inside of Kavachi's caldera and its flanks. Here we present medium-resolution bathymetry of the main peak paired with benthic imagery, petrologic analysis of samples from the caldera rim, measurements of gas flux over the main peak, and hydrothermal plume structure data. A second peak was discovered to the Southwest of the main cone and displayed evidence of diffuse-flow venting. Populations of gelatinous animals, small fish, and sharks were observed inside the active crater, raising new questions about the ecology of active submarine volcanoes. Most equipment used in this study was lightweight, relatively low-cost, and deployed using small boats; these methods may offer developing nations an economic means to explore deep-sea environments within their own territorial waters.

  4. The role of slab melting in the petrogenesis of high-Mg andesites: evidence from Simbo Volcano, Solomon Islands

    NASA Astrophysics Data System (ADS)

    König, S.; Schuth, S.; Münker, C.; Qopoto, C.

    2007-01-01

    The petrogenesis of high-Mg andesites (HMA) in subduction zones involves shallow melting of refractory mantle sources or, alternatively, the interaction of ascending slab-derived melts with mantle peridotite. To unravel the petrogenesis of HMA, we report major, trace element and Sr-Nd-Hf-Pb isotope data for a newly found occurrence of HMA in the New Georgia group, Solomon Islands, SW-Pacific. Volcanism in the Solomon Islands was initiated by subduction of the Pacific plate beneath the Indian-Australian plate until a reversal of subduction polarity occurred ca. 10 Ma ago. Currently, the Indian-Australian plate is subducted northeastwards along the San Cristobál trench, forming the younger and still active southwestern Solomon island arc. However, a fossil slab of Pacific crust is still present beneath the arc. The edifice of the active volcano Simbo is located directly in the San Cristobál trench on top of the subducting Indian-Australian plate. Simbo Island lies on top of a strike-slip fault of the adjacent Woodlark spreading centre that is subducted beneath the Pacific plate. Geochemical and petrological compositions of volcanic rocks from Simbo are in marked contrast to those of volcanic rocks from islands north of the trench (mostly arc basalts). Simbo-type rocks are opx-bearing HMA, displaying 60-62 wt% SiO2 but rather primitive Mg-Ni-Cr characteristics with 4-6 wt% MgO, up to 65 ppm Ni, up to 264 ppm Cr and Mg# from 67 to 75. The compositions of the Simbo andesites are explained by a binary mixture of silicic and basaltic melts. Relict olivine phenocrysts with Fo88-90 and reaction-rims of opx also support a mixing model. The basaltic endmember is similar to back-arc basalts from the Woodlark Ridge. A slab melt affinity of the silicic mixing component is indicated by Gd(N)/Yb(N) of up to 2.2 that is higher if compared to MORB and other arc basalts from the Solomon Islands. 87Sr/86Sr, ɛNd and ɛHf values in the analysed rocks range from 0.7035 to 0.7040, +6

  5. Yaws in the Solomon Islands.

    PubMed

    Fegan, D; Glennon, M; Macbride-Stewart, G; Moore, T

    1990-02-01

    Yaws is a chronic, relapsing, non-venereally transmitted disease caused by Treponema pertenue. As a result of the WHO mass treatment campaign of the late 1950s, the prevalence in the Solomon Islands fell dramatically. Here the disease was thought to have been eradicated until an outbreak occurred in 1981. In 1984 a mass treatment survey following modified WHO guidelines was carried out. Subsequent to this campaign, yaws recurred and in 1987 a further treatment survey was required. Two observations were made as a result of our recent experience in controlling yaws in the Solomon Islands. (1) The disease appears to be attenuated. (2) WHO control policy may now be an inappropriate method for dealing with yaws in the Solomon Islands and should be replaced by a method which is integrated into the existing primary health care (PHC) structure. PMID:2304133

  6. In Brief: Tsunami hits the Solomon Islands

    NASA Astrophysics Data System (ADS)

    Zielinski, Sarah

    2007-04-01

    A magnitude 8.1 earthquake shook the Solomon Islands on 1 April at approximately 7:40 A.M. local time. The earthquake generated a tsunami several meters high that struck many of the islands. The earthquake occurred along the boundary of the Pacific plate where the Australia, Woodlark, and Solomon Sea plates subduct beneath it, according to the U.S. Geological Survey's Earthquake Hazards Program. At least 34 people were killed by the tsunami and several dozen more are still missing, according to the National Disaster Council in the Solomon Islands. The NDC estimates that 900-2500 homes were destroyed by the tsunami, displacing about 5500 people.

  7. Oloketa Tingting Fo Apem Education Long Solomon Islands: Issues in Solomon Islands Education

    ERIC Educational Resources Information Center

    Alcorn, Noeline

    2010-01-01

    This book makes available to a wider audience for the first time material based on fieldwork carried out by the Solomon Island researchers in their own country. The findings will have vital relevance to policy makers, teachers and students. Over the past four years the School of Education, Solomon Islands College of Higher Education and the…

  8. Magnitude 8.1 Earthquake off the Solomon Islands

    NASA Technical Reports Server (NTRS)

    2007-01-01

    On April 1, 2007, a magnitude 8.1 earthquake rattled the Solomon Islands, 2,145 kilometers (1,330 miles) northeast of Brisbane, Australia. Centered less than ten kilometers beneath the Earth's surface, the earthquake displaced enough water in the ocean above to trigger a small tsunami. Though officials were still assessing damage to remote island communities on April 3, Reuters reported that the earthquake and the tsunami killed an estimated 22 people and left as many as 5,409 homeless. The most serious damage occurred on the island of Gizo, northwest of the earthquake epicenter, where the tsunami damaged the hospital, schools, and hundreds of houses, said Reuters. This image, captured by the Landsat-7 satellite, shows the location of the earthquake epicenter in relation to the nearest islands in the Solomon Island group. Gizo is beyond the left edge of the image, but its triangular fringing coral reefs are shown in the upper left corner. Though dense rain forest hides volcanic features from view, the very shape of the islands testifies to the geologic activity of the region. The circular Kolombangara Island is the tip of a dormant volcano, and other circular volcanic peaks are visible in the image. The image also shows that the Solomon Islands run on a northwest-southeast axis parallel to the edge of the Pacific plate, the section of the Earth's crust that carries the Pacific Ocean and its islands. The earthquake occurred along the plate boundary, where the Australia/Woodlark/Solomon Sea plates slide beneath the denser Pacific plate. Friction between the sinking (subducting) plates and the overriding Pacific plate led to the large earthquake on April 1, said the United States Geological Survey (USGS) summary of the earthquake. Large earthquakes are common in the region, though the section of the plate that produced the April 1 earthquake had not caused any quakes of magnitude 7 or larger since the early 20th century, said the USGS.

  9. Nativization and Anglicization in Solomon Islands Pijin.

    ERIC Educational Resources Information Center

    Jourdan, Christine

    1989-01-01

    A study investigated the extent of anglicization of Solomon Islands Pijin, the primary language for Honiara, the nation's capital. It was found that the influence of English was not related to the creolization of Pijin but rather to the bilingualism of the speakers of Pijin and to their high degree of fluency and contact with English. (Author/CB)

  10. Vernacular Literacy in the Touo Language of the Solomon Islands

    ERIC Educational Resources Information Center

    Dunn, Michael

    2005-01-01

    The Touo language is a non-Austronesian language spoken on Rendova Island (Western Province, Solomon Islands). First language speakers of Touo are typically multilingual, and are likely to speak other (Austronesian) vernaculars, as well as Solomon Island Pijin and English. There is no institutional support of literacy in Touo: schools function in…

  11. Development of Rural Libraries in the Solomon Islands.

    ERIC Educational Resources Information Center

    Evans, John

    1992-01-01

    Discusses recent developments in extending library services into provincial centers and rural areas in the Solomon Islands. Topics addressed include background on library development in the Solomon Islands, the establishment of the National Library Service, links to government policy, rural library history and development, provincial libraries,…

  12. Solomon Islands School Leaders Readiness for Inclusive Education

    ERIC Educational Resources Information Center

    Porakari, James; Sevala, Brenda; Miniti, Patrick; Saemane, George; Sharma, Umesh; Forlin, Chris

    2015-01-01

    The inclusion of students with disabilities was initiated by the Ministry of Education and Human Resource Development in the Solomon Islands in 2013. This paper investigates the knowledge, skills, and values of school leaders in public and private schools in Honiara, the capital of the Solomon Islands, in regard to providing support for inclusive…

  13. Domestic violence in the Solomon Islands

    PubMed Central

    Ming, Mikaela A.; Stewart, Molly G.; Tiller, Rose E.; Rice, Rebecca G.; Crowley, Louise E.; Williams, Nicola J.

    2016-01-01

    The Solomon Islands has one of the highest rates of family and sexual violence (FSV) in the world with 64% of women aged 15–49 have reported physical and/or sexual abuse by a partner. The National Referral Hospital (NRH) in the capital, Honiara, is the only tertiary hospital for the country. Our 4-week medical elective at the NRH was spent reflecting on healthcare challenges including FSV, with the aim of identifying cases of FSV and assessing on the current strategies to improve care for victims. Throughout our placement, we encountered many cases of probable FSV, particularly in the Emergency Department and Obstetrics and Gynecology. These patients were often not managed effectively, largely due to time pressures and overcrowding in the hospital. However, we identified a number of strategies, which have recently been implemented in order to help FSV victims in the Solomon Islands. These include strategies within the healthcare setting, in particular, the commencement of FSV reporting within the hospital, and the production of a manual to enable healthcare worker education on the issue. Strategies within the criminal justice system are also in place. These include recent changes in legislation and the work of the volunteer police force, Royal Assist Mission to the Solomon Islands, to improve attitudes toward FSV. These approaches to tackle the problem of FSV are currently in their early stages and have largely stemmed from Western policies and ideals. This report concludes that more time is needed to accurately assess the impact of the current changes before further recommendations are made. PMID:27453837

  14. Domestic violence in the Solomon Islands.

    PubMed

    Ming, Mikaela A; Stewart, Molly G; Tiller, Rose E; Rice, Rebecca G; Crowley, Louise E; Williams, Nicola J

    2016-01-01

    The Solomon Islands has one of the highest rates of family and sexual violence (FSV) in the world with 64% of women aged 15-49 have reported physical and/or sexual abuse by a partner. The National Referral Hospital (NRH) in the capital, Honiara, is the only tertiary hospital for the country. Our 4-week medical elective at the NRH was spent reflecting on healthcare challenges including FSV, with the aim of identifying cases of FSV and assessing on the current strategies to improve care for victims. Throughout our placement, we encountered many cases of probable FSV, particularly in the Emergency Department and Obstetrics and Gynecology. These patients were often not managed effectively, largely due to time pressures and overcrowding in the hospital. However, we identified a number of strategies, which have recently been implemented in order to help FSV victims in the Solomon Islands. These include strategies within the healthcare setting, in particular, the commencement of FSV reporting within the hospital, and the production of a manual to enable healthcare worker education on the issue. Strategies within the criminal justice system are also in place. These include recent changes in legislation and the work of the volunteer police force, Royal Assist Mission to the Solomon Islands, to improve attitudes toward FSV. These approaches to tackle the problem of FSV are currently in their early stages and have largely stemmed from Western policies and ideals. This report concludes that more time is needed to accurately assess the impact of the current changes before further recommendations are made. PMID:27453837

  15. Solomon Islands Tsunami, One Year Later

    NASA Astrophysics Data System (ADS)

    McAdoo, Brian G.; Fritz, Hermann; Jackson, Kelly L.; Kalligeris, Nikos; Kruger, Jens; Bonte-Grapentin, Michael; Moore, Andrew L.; Rafiau, Wilson B.; Billy, Douglas; Tiano, Braddley

    2008-04-01

    The geologic and economic effects of the 2 April 2007 Solomon Islands earthquake and tsunami are distinctly visible a little more than a year after the event. Coral reef colonies that were sheared off and uplifted are slowly recovering, and many new earthquake-triggered landslides remain mobile. Large volumes of sediment created by the earthquake and mobilized by the tsunami have been flushed from the lagoons between the reef and shoreline into deeper water, although significant quantities remain on land. Sediment from the lagoons covers piles of shattered coral that the tsunami moved from the lagoons to the base of channels in the barrier reef. These shattered corals have a higher chance of preservation as paleotsunami deposits than the material deposited on land.

  16. Mental health services in the Solomon Islands.

    PubMed

    Orotaloa, Paul; Blignault, Ilse

    2012-06-01

    The Solomon Islands comprise an archipelago of nearly 1,000 islands and coral atolls and have an estimated population of 549,574 people. Formal mental health services date back to 1950 when an asylum was established. Since then the process of mental health service development has been largely one of incremental change, with a major boost to community services in the last two decades. During the 1990s a mental health outpatient clinic was established in Honiara, together with attempts to recruit nursing staff as psychiatric coordinators in the provinces. In 1996, the Ministry commenced sending registered nurses for psychiatric training in Papua New Guinea. By 2010, there were 13 psychiatric nurses and one psychiatrist, with a second psychiatrist in training. A National Mental Health Policy was drafted in 2009 but is yet to be endorsed by Cabinet. A significant portion of the population still turns to traditional healers or church leaders for purposes of healing, seeking help from Western medicine only after all other alternatives in the community have been exhausted. There is still a long way to go before mental health services are available, affordable and accessible to the whole population, including people living in geographically remote areas. Realization of this vision requires increased resourcing for mental health services; improved communication and collaboration between the centrally-based, national mental health services and the provincial health services; and closer, ongoing relationships between all stakeholders and partners, both locally and internationally. PMID:26767360

  17. Mental health services in the Solomon Islands.

    PubMed

    Orotaloa, Paul; Blignault, Ilse

    2012-06-01

    The Solomon Islands comprise an archipelago of nearly 1,000 islands and coral atolls and have an estimated population of 549,574 people. Formal mental health services date back to 1950 when an asylum was established. Since then the process of mental health service development has been largely one of incremental change, with a major boost to community services in the last two decades. During the 1990s a mental health outpatient clinic was established in Honiara, together with attempts to recruit nursing staff as psychiatric coordinators in the provinces. In 1996, the Ministry commenced sending registered nurses for psychiatric training in Papua New Guinea. By 2010, there were 13 psychiatric nurses and one psychiatrist, with a second psychiatrist in training. A National Mental Health Policy was drafted in 2009 but is yet to be endorsed by Cabinet. A significant portion of the population still turns to traditional healers or church leaders for purposes of healing, seeking help from Western medicine only after all other alternatives in the community have been exhausted. There is still a long way to go before mental health services are available, affordable and accessible to the whole population, including people living in geographically remote areas. Realization of this vision requires increased resourcing for mental health services; improved communication and collaboration between the centrally-based, national mental health services and the provincial health services; and closer, ongoing relationships between all stakeholders and partners, both locally and internationally.

  18. Anatahan Volcano, Mariana Islands

    NASA Technical Reports Server (NTRS)

    2008-01-01

    In the early hours of February 7, ASTER captured this nighttime thermal infrared image of an eruption of Anatahan Volcano in the central Mariana Islands. The summit of the volcano is bright indicating there is a very hot area there. Streaming to the west is an ash plume, visible by the red color indicating the presence of silicate-rich particles. Dark grey areas are clouds that appear colder than the ocean. Anatahan is a stratovolcano that started erupting in May 2003, forming a new crater.

    The image covers an area of 56.3 x 41.8 km, and is located 16 degrees north latitude and 145.6 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  19. Solomon Islands: reaching street children in Honiara.

    PubMed

    Gatu, R

    2000-01-01

    The situation of homeless children in Honiara, Solomon Islands had attracted the attention of Sister Doreen of the Angelican Sisters of the Church. One discovery was that these young people had little knowledge of sexuality but were often sexually active. This article discusses the workshop developed by the Angelican Sisters of the Church that addresses the needs of the youth, particularly on the topics of adolescent sexual and reproductive health and HIV/AIDS and sexually transmitted diseases (STDs). About 34 young people attended the 4-day seminar, which aimed to empower the kids into making the right decision and changing their behavior. Among the activities during the program were the use of games, information and practical sessions, which included a condom demonstration in the form of a bingo game. The workshop was a success, with kids started teaching their peers and parents and more requests for such workshops indicated that young people in Honoria are hungry for information on sex, sexuality, HIV/AIDS and STDs.

  20. Telemedicine in the Solomon Islands: 2006 to 2009.

    PubMed

    Martiniuk, Alexandra; Negin, Joel; Hersch, Fred; Dalipanda, Tenneth; Jagilli, Rooney; Houasia, Patrick; Gorringe, Lilijana; Christie, Annie

    2011-01-01

    Telemedicine has been used in the Solomon Islands since 2000. We used quantitative and qualitative methods to examine telemedicine use in the Solomon Islands from January 2006 to June 2009. During the study period 66 telemedicine cases were submitted to the store and forward telemedicine system being used there. These included orthopaedic, oncology, cardiothoracic, infectious, congenital, gastroenterology and dermatology cases. Most cases (52%) were submitted by doctors at the National Referral Hospital (NRH) in Honiara. The majority of responses came from the NRH (27%). A final, firm recommendation regarding patient diagnosis and/or care was given for 46% of the cases. Interviews were conducted with 23 stakeholders in the Solomon Islands and in Australia to better understand the current and future use of telemedicine. The interviews identified the fragility of the Solomon Islands infrastructure, including the lack of training, as the largest barrier to the future use of telemedicine. The best use of telemedicine appears to be case sharing within the Solomon Islands, with connections to clinicians in other countries as a secondary benefit when particular expertise is required. PMID:21628420

  1. Telemedicine in the Solomon Islands: 2006 to 2009.

    PubMed

    Martiniuk, Alexandra; Negin, Joel; Hersch, Fred; Dalipanda, Tenneth; Jagilli, Rooney; Houasia, Patrick; Gorringe, Lilijana; Christie, Annie

    2011-01-01

    Telemedicine has been used in the Solomon Islands since 2000. We used quantitative and qualitative methods to examine telemedicine use in the Solomon Islands from January 2006 to June 2009. During the study period 66 telemedicine cases were submitted to the store and forward telemedicine system being used there. These included orthopaedic, oncology, cardiothoracic, infectious, congenital, gastroenterology and dermatology cases. Most cases (52%) were submitted by doctors at the National Referral Hospital (NRH) in Honiara. The majority of responses came from the NRH (27%). A final, firm recommendation regarding patient diagnosis and/or care was given for 46% of the cases. Interviews were conducted with 23 stakeholders in the Solomon Islands and in Australia to better understand the current and future use of telemedicine. The interviews identified the fragility of the Solomon Islands infrastructure, including the lack of training, as the largest barrier to the future use of telemedicine. The best use of telemedicine appears to be case sharing within the Solomon Islands, with connections to clinicians in other countries as a secondary benefit when particular expertise is required.

  2. Schooling, Knowledge, and Power: Social Transformation in the Solomon Islands.

    ERIC Educational Resources Information Center

    Watson-Gegeo, Karen Ann; Gegeo, David Welchman

    1992-01-01

    Compares traditional education with national schooling in the Solomon Islands, concentrating on the nature, meaning, and transmission of knowledge and impact of the Western model of schooling on social change. Historical sources, government reports, interviews, and observations of the Kwara'ae, the largest cultural group in the islands, are…

  3. Solomon Islands Pijin: Teacher's Handbook. Peace Corps Language Handbook Series.

    ERIC Educational Resources Information Center

    Clark, Raymond C.; Huebner, Thom

    This teacher's guide is designed to accompany the three Peace Corps students' books in Pijin, the language of the Solomon Islands. Its goal is to help the native speaker understand the American volunteers' viewpoints and to provide detailed information on methods and techniques for teaching the language and culture. The guide has three parts: (1)…

  4. Solomon Islands Pijin: Grammar Handbook. Peace Corps Language Handbook Series.

    ERIC Educational Resources Information Center

    Huebner, Thom; Horoi, Stephen Rex

    This grammar handbook analyzes the rules of Solomon Islands Pijin and provides exercises on them. It is divided into 24 lessons. The first part of each lesson is a description of some element or function of the language, with examples; the second part is made up of oral and written exercises. The volume concludes with appendices on the personal…

  5. Haemophilus ducreyi associated with skin ulcers among children, Solomon Islands.

    PubMed

    Marks, Michael; Chi, Kai-Hua; Vahi, Ventis; Pillay, Allan; Sokana, Oliver; Pavluck, Alex; Mabey, David C; Chen, Cheng Y; Solomon, Anthony W

    2014-10-01

    During a survey of yaws prevalence in the Solomon Islands, we collected samples from skin ulcers of 41 children. Using PCR, we identified Haemophilus ducreyi infection in 13 (32%) children. PCR-positive and PCR-negative ulcers were phenotypically indistinguishable. Emergence of H. ducreyi as a cause of nongenital ulcers may affect the World Health Organization's yaws eradication program. PMID:25271477

  6. Haemophilus ducreyi Associated with Skin Ulcers among Children, Solomon Islands

    PubMed Central

    Chi, Kai-Hua; Vahi, Ventis; Pillay, Allan; Sokana, Oliver; Pavluck, Alex; Mabey, David C.; Chen, Cheng Y.; Solomon, Anthony W.

    2014-01-01

    During a survey of yaws prevalence in the Solomon Islands, we collected samples from skin ulcers of 41 children. Using PCR, we identified Haemophilus ducreyi infection in 13 (32%) children. PCR-positive and PCR-negative ulcers were phenotypically indistinguishable. Emergence of H. ducreyi as a cause of nongenital ulcers may affect the World Health Organization’s yaws eradication program. PMID:25271477

  7. Aid for Education in Post-Conflict Solomon Islands

    ERIC Educational Resources Information Center

    Whalan, Jeni

    2011-01-01

    Between 1998 and 2003, conflict, violent crime, and a severe economic downturn pushed the Solomon Islands state to the brink of failure, exacerbating the problems of an already struggling education sector. Most schools on Guadalcanal were seriously disrupted; some were burned down or vandalized, others closed as teachers and students fled…

  8. Spatial Terms, Polysemy and Possession in Longgu (Solomon Islands).

    ERIC Educational Resources Information Center

    Hill, Deborah; Goddard, Cliff

    1997-01-01

    Identifies lexical equivalents of semantic primitives "above, under, inside, on the side," as defined by Natural Semantic Metalanguage theory, in Longgu (Solomon Islands) and argues that the first three have both a semantically primitive rational sense and a secondary topological sense. Morphosyntactic issues are discussed, including their status…

  9. Iumi Lanem Pijin. A Basic Course in Solomon Islands Pidgin.

    ERIC Educational Resources Information Center

    Labu, Francis, Ed.; Marshall, Ann C., Ed.

    A set of instructional materials for introductory Solomon Islands Pidgin, an English-based pidgin, is designed for Peace Corps volunteer language instruction. It consists of 12 units that contain dialogues, grammar and pronunciation notes, pattern and substitution drills, lists of vocabulary and useful expressions, and exercises based on the…

  10. Amendment to the Solomon Islands National Provident Fund Act.

    PubMed

    1989-01-01

    On 6 June 1988 the Solomon Islands National Provident Fund Act was amended to allow the Solomon Islands National Provident Fund Board to grant loans to members of the Fund. In November 1989 under authority of this amendment the Board implemented a housing scheme for members of the Fund. It instituted loans for the purchase of residential homes from property owners, the construction of residential houses, and the redemption of bank loans obtained for purchase or construction of residential houses. To qualify for the loan the applicant must be a permanent employee, be an active member of the Fund, and less than 50 years old, and the house sought to be purchased or built must be on registered land.

  11. Remuneration disparities in Oceania: Papua New Guinea and Solomon Islands.

    PubMed

    Marai, Leo; Kewibu, Vincent; Kinkin, Elly; Peter Peniop, John; Salini, Christian; Kofana, Genesis

    2010-10-01

    This paper explores the impact of remuneration differences on workers in the Solomon Islands and Papua New Guinea. In these countries remunerative differences are linked to government policy (in Papua New Guinea) and job contracts (in the Solomon Islands), and have impacted on industrial relations in both settings (strike action). A total of N = 350 professionals (n = 60 expatriates) from 54 organizations in aid, government, higher education and industry (mean response rate = 36%) responded to an organizational survey form. Remuneration ratios between international and local respondents based on the World Bank's index of purchasing power parity approached 9:1. In both sites staff compared pay and benefits (remuneration) packages: Internationally remunerated staff rated their ability higher than their local counterparts did; locally remunerated groups reported more injustice in remuneration, were more demotivated by the gaps, and were more likely to be thinking about leaving the organization. In-country workshops of N = 40 largely local stakeholders from aid and community organizations plus government ministries considered the survey's findings and recommended: in Solomon Islands, (a) introducing a policy of localization, (b) establishing a remuneration commission (already existent in Papua New Guinea), and (c) reducing the remunerative gap; in Papua New Guinea, (d) reversing the post-Independence "dual pay system" (currently official policy), (e) instituting pay-for-performance, and (f) ensuring the existent localization policy is applied to recruitment, selection, and staff career planning and management.

  12. Remuneration disparities in Oceania: Papua New Guinea and Solomon Islands.

    PubMed

    Marai, Leo; Kewibu, Vincent; Kinkin, Elly; Peter Peniop, John; Salini, Christian; Kofana, Genesis

    2010-10-01

    This paper explores the impact of remuneration differences on workers in the Solomon Islands and Papua New Guinea. In these countries remunerative differences are linked to government policy (in Papua New Guinea) and job contracts (in the Solomon Islands), and have impacted on industrial relations in both settings (strike action). A total of N = 350 professionals (n = 60 expatriates) from 54 organizations in aid, government, higher education and industry (mean response rate = 36%) responded to an organizational survey form. Remuneration ratios between international and local respondents based on the World Bank's index of purchasing power parity approached 9:1. In both sites staff compared pay and benefits (remuneration) packages: Internationally remunerated staff rated their ability higher than their local counterparts did; locally remunerated groups reported more injustice in remuneration, were more demotivated by the gaps, and were more likely to be thinking about leaving the organization. In-country workshops of N = 40 largely local stakeholders from aid and community organizations plus government ministries considered the survey's findings and recommended: in Solomon Islands, (a) introducing a policy of localization, (b) establishing a remuneration commission (already existent in Papua New Guinea), and (c) reducing the remunerative gap; in Papua New Guinea, (d) reversing the post-Independence "dual pay system" (currently official policy), (e) instituting pay-for-performance, and (f) ensuring the existent localization policy is applied to recruitment, selection, and staff career planning and management. PMID:22044056

  13. 75 FR 18056 - Safety Zone; Fireworks Display, Patuxent River, Solomons Island Harbor, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-09

    ... Island Harbor, MD AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is establishing a temporary safety zone upon specified waters of Solomons Island Harbor, a tributary of the... fireworks display launched from discharge barge located in Solomons Island, Calvert County, Maryland....

  14. Sector wide approaches for health in small island states: lessons learned from the Solomon Islands.

    PubMed

    Negin, Joel; Martiniuk, Alexandra

    2012-01-01

    Sector Wide Approaches (SWAps) have increasingly been implemented in countries around the world as a mechanism for effective delivery of health sector funding from various sources. Despite the global focus on aid effectiveness, SWAps have been under-examined. In 2007, the Solomon Islands and development partners began discussing a health SWAp making the Solomon Islands one of the first fragile states globally to adopt a SWAp. This paper explores the establishment and implementation of a health SWAp in the Solomon Islands as a specific case study with lessons learned for the region as well as for aid architecture in fragile states more generally. Tensions between donors and the government impeded agreement and early implementation and country ownership of the SWAp idea was muted. Since mid-2009, however, the Solomon Islands SWAp has made strong progress with greater government ownership and with more focus on partnership and harmonisation rather than on funding mechanisms. The SWAp mechanism has been a challenge for the capacity-constrained Solomon Islands health sector and for development partners familiar with other aid modalities, but current momentum suggests that the SWAp will have a positive impact on adherence to agreed aid effectiveness principles. PMID:21736517

  15. Sector wide approaches for health in small island states: lessons learned from the Solomon Islands.

    PubMed

    Negin, Joel; Martiniuk, Alexandra

    2012-01-01

    Sector Wide Approaches (SWAps) have increasingly been implemented in countries around the world as a mechanism for effective delivery of health sector funding from various sources. Despite the global focus on aid effectiveness, SWAps have been under-examined. In 2007, the Solomon Islands and development partners began discussing a health SWAp making the Solomon Islands one of the first fragile states globally to adopt a SWAp. This paper explores the establishment and implementation of a health SWAp in the Solomon Islands as a specific case study with lessons learned for the region as well as for aid architecture in fragile states more generally. Tensions between donors and the government impeded agreement and early implementation and country ownership of the SWAp idea was muted. Since mid-2009, however, the Solomon Islands SWAp has made strong progress with greater government ownership and with more focus on partnership and harmonisation rather than on funding mechanisms. The SWAp mechanism has been a challenge for the capacity-constrained Solomon Islands health sector and for development partners familiar with other aid modalities, but current momentum suggests that the SWAp will have a positive impact on adherence to agreed aid effectiveness principles.

  16. Comparison of the 2010 and 2007 Solomon Island Tsunamis

    NASA Astrophysics Data System (ADS)

    Kalligeris, N.; Fritz, H.; Newman, A. V.; Feng, L.; Lifton, Z. M.; Wei, Y.; Titov, V. V.; Uslu, B. U.

    2010-12-01

    The 3 January 2010 Mw 7.1 earthquake off Rendova and Tetepare Islands, Western Province, Solomon Islands, generated surprisingly large tsunami waves, completely destroying Retavo village at Rendova Island’s south shore, located approximately 15 km from the trench. A reconnaissance team was deployed within a week, measuring local tsunami heights, maximum tsunami runup/inundation, coastal subsidence, co-seismic offset and afterslip, and interviewed eyewitnesses per established methods. This event occurred three years after the 1 April 2007 Mw 8.1 megathrust earthquake that generated a wide-spread tsunami across the Western Province Islands, causing 52 human casualties (Fritz and Kalligeris 2008). Although much smaller in magnitude than the 2007 event (below the assumed tsunamigenic magnitude threshold of ~Mw 7.5), the 2010 event produced a larger localized flow depth, and only moderately smaller runup, reaching a maximum value of 7 m on the southern shore of Rendova Isl. Observations of widespread subsidence on the south coasts of Rendova and Tetepare Islands ruled out the most probable shallow-dipping megathrust model of earthquake rupture. Instead, a high-angle conjugate intraslab thrust within the down going plate is preferred, agreeing with the seismically defined moment tensor, the observed coseismic subsidence, and enhanced tsunami excitation. The two events showed that SI population is very aware of its vulnerability to tsunamis, which we attribute to ancestral tsunami knowledge. Similar observations were made in Chile this year, where residents in most areas self-evacuated, significantly containing human casualties. We will compare the two Solomon Island events, in terms of our field findings, the source deformation models that best fit the observations, and present preliminary tsunami modeling results. Inundation in Tapurai village, Simbo Island in 2007 (left), and in Retavo village, Rendova Island in 2010 (right).

  17. The State of Libraries in Solomon Islands in the 1990s.

    ERIC Educational Resources Information Center

    Dadalo, Tony

    The purpose of this research project was to examine the current state of libraries in the Solomon Islands with particular attention to the resources available and the services provided. Data was collected through a survey questionnaire, site visits, and informal interviews carried out in the Solomon Islands between July and August 1998. The 20…

  18. Tsunami awareness saves Solomon Islanders on 1 April 2007

    NASA Astrophysics Data System (ADS)

    Fritz, H. M.; Kalligeris, N.

    2007-12-01

    On April 1, 2007 at 20:39:56 UTC (local time: UTC+11), a magnitude Ms 8.1 earthquake occurred 50 km off the New Georgia Islands in the Solomon Sea generating a locally focused tsunami striking more than 300 coastal communities in the Solomon Islands. A reconnaissance team deployed within one week investigated 65 coastal settlements on 13 remote Islands and measured run-up heights of 12 m, local flow depths of 5 m as well as tectonic uplift up to 3.6 m and subsidence down to -1.5m. This South Pacific archipelago's worst disaster since WWII resulted in 52 confirmed death and 36'000 directly affected - roughly half of these numbers are children. The ground shaking pinned people to the ground and palm trees bounced back and forth with leafs touching the ground. The ancestral heritage "run to high ground after an earthquake" passed on to younger generations by survivors of a smaller 1952 tsunami triggered an immediate spontaneous self evacuation, which dramatically reduced the death toll in the small evacuation window of a few minutes between the end of the ground shaking and the onslaught of the tsunami. The survivors remained traumatized by the tsunami, afraid of the sea and living in evacuation camps on the hills illustrating the importance of community-based education and awareness programs.

  19. The Education Pacific Islands Children Deserve: The Learn and Play Project in the Solomon Islands

    ERIC Educational Resources Information Center

    Maebuta, Jack

    2011-01-01

    The Learn and Play Project was initiated by Solomon Islands Football Federation and aimed at educating and providing football skills training for primary school dropouts. The aim of this paper is to report the implementation of the programme in a case study school. Because the project is still being implemented, this paper is not intended to…

  20. A Case of Ancylostoma ceylanicum Infection Occurring in an Australian Soldier Returned from Solomon Islands

    PubMed Central

    Speare, Rick; Bradbury, Richard Stewart; Croese, John

    2016-01-01

    A 26-year-old male member of the Australian Defense Force presented with a history of central abdominal pain of 4 weeks duration and peripheral eosinophilia consistent with eosinophilic enteritis. Acute hookworm disease was diagnosed as the cause. Adult worms recovered from feces after therapy with albendazole were morphologically consistent with Ancylostoma ceylanicum. As the patient had been deployed with the Regional Assistance Mission to Solomon Islands for 6 months prior to this presentation, it is very likely that the A. ceylanicum was acquired in Solomon Islands. Until now, it has been assumed that any Ancylostoma spp. recovered from humans in Solomon Islands is A. duodenale. However, this case demonstrates that human hookworm infection acquired in the Solomon Islands could be caused by A. ceylanicum. PMID:27658607

  1. A Case of Ancylostoma ceylanicum Infection Occurring in an Australian Soldier Returned from Solomon Islands.

    PubMed

    Speare, Rick; Bradbury, Richard Stewart; Croese, John

    2016-08-01

    A 26-year-old male member of the Australian Defense Force presented with a history of central abdominal pain of 4 weeks duration and peripheral eosinophilia consistent with eosinophilic enteritis. Acute hookworm disease was diagnosed as the cause. Adult worms recovered from feces after therapy with albendazole were morphologically consistent with Ancylostoma ceylanicum. As the patient had been deployed with the Regional Assistance Mission to Solomon Islands for 6 months prior to this presentation, it is very likely that the A. ceylanicum was acquired in Solomon Islands. Until now, it has been assumed that any Ancylostoma spp. recovered from humans in Solomon Islands is A. duodenale. However, this case demonstrates that human hookworm infection acquired in the Solomon Islands could be caused by A. ceylanicum. PMID:27658607

  2. Scale, Sovereignty, Wealth and Enterprise: Social and Educational Comparisons between the Cook Islands and the Solomon Islands.

    ERIC Educational Resources Information Center

    Crocombe, Ron; Crocombe, Marjorie Tuainekore

    1993-01-01

    Compares the Cook Islands (a small Pacific Island country) and the Solomon Islands (one of the largest) with regard to availability of postcompulsory education. Suggests that postschool educational benefits are positively associated with smallness (resulting in higher per capita international aid), per capita income, foreign investment,…

  3. Field evaluation of deet against Anopheles farauti at Ndendo (Santa Cruz) Island, Solomon Islands.

    PubMed

    Frances, S P; Bugoro, H; Butafa, C; Cooper, R D

    2010-09-01

    Field efficacy studies comparing two formulations of deet (N,N-diethyl-3-methylbenzamide) against mosquitoes were conducted on Ndendo Island, Solomon Islands. The repellent study was conducted at Pala village in November 2008, and the only mosquito species collected was Anopheles farauti Laveran. A formulation containing 35% deet in a gel provided >95% protection for 2 h, whereas a formulation containing 40% deet in ethanol in a spray applicator provided >95% for only 1 h. This field study demonstrated again that repellents containing deet provide a relatively short period of complete protection against Anopheles spp. PMID:20939380

  4. Counting the Cost of Diabetes in the Solomon Islands and Nauru

    PubMed Central

    Win Tin, Si Thu; Iro, George; Gadabu, Eva; Colagiuri, Ruth

    2015-01-01

    Aim To determine the costs associated with diabetes to governments, people with diabetes and their carers, and its impact on quality of life in two Pacific Island countries—the Solomon Islands and Nauru. Materials and Methods This cross-sectional cost of illness study was conducted on 330 people with type 2 diabetes (197 from the Solomon Islands and 133 from Nauru) using a structured cost of illness survey questionnaire adapted from the Australian DiabCo$t study. Quality of life was measured by the EQ-5D Visual Analogue Scale. Results There were 330 respondents (50% female; mean duration of diabetes 10.9 years; mean age 52.6 years). The estimated annual national cost of diabetes incurred by the Solomon Islands government was AUD12.8 million (AUD281 per person/year) and by Nauru government was AUD1.2 million (AUD747 per person/year). The major contribution to the government costs was inpatient services cost (71% in the Solomon Islands and 83% in Nauru). Annual expenditure for diabetes was approximately 20% of the governments’ annual health care expenditure. Considerable absenteeism and retirement from work due to diabetes was found. Conclusions This study found substantial public and personal costs associated with diabetes. The findings provide objective data on which health policy, funding and planning decisions about the prevention and control of diabetes in the Solomon Islands and Nauru can be reliably based and subsequently evaluated. PMID:26698575

  5. Emergency safe spaces in Haiti and the Solomon Islands.

    PubMed

    Madfis, Josh; Martyris, Daryl; Triplehorn, Carl

    2010-07-01

    This paper provides background information on emergency Safe Spaces for children and specific information for responses in Haiti and the Solomon Islands. In 2007, both countries experienced natural disasters that resulted in internal displacement of thousands of people. The Save the Children Alliance created Safe Spaces for children living in camps for internally displaced persons. The project sought to accomplish 'B-SAFE' strategies through emergency education, psychosocial, and protection interventions. The B-SAFE strategies are to (B)uild relationships, cooperation, and respect among peers; to (S)creen for high-risk children and youth; (A)ctive, structured learning and life saving information; to (F)acilitate children's natural resilience and a return to normalcy; and to (E)stablish a sense of security and self-esteem. The project made use of child and parent surveys and observation tools that measured B-SAFE indicators. Analysed data demonstrated an improvement in children's behavior participating in the programme. PMID:20345461

  6. Solomon Islands Pijin: Special Skills Handbook. Peace Corps Language Handbook Series.

    ERIC Educational Resources Information Center

    Huebner, Thom, Comp.

    This handbook is intended to acquaint Peace Corps volunteers with the geography and culture of the Solomon Islands. It is divided into five parts: (1) an atlas of pen-and-ink maps of the islands; (2) custom stories in Pijin, with an English translation of each one; (3) miscellaneous readings in Pijin; (4) posters in Pijin; and (5) a picture…

  7. Language, Aid and Literacy: An Outline of Activities in the Solomon Islands.

    ERIC Educational Resources Information Center

    Moseley, Lesley

    1994-01-01

    Problems facing the literacy movement in the Solomon Islands are related to communication, economic, and linguistic barriers. The island is linguistically diverse. English is the official language, but a national literacy committee found that only 26% of people could speak English. Improving primary education is a government priority. Training of…

  8. Solomon Islands: Summary Report. Educational Experience Survey: Education, Language and Literacy Experience. Asia-South Pacific Education Watch

    ERIC Educational Resources Information Center

    de Guzman, Sylvia

    2007-01-01

    The Education Watch initiative is being implemented in the Solomon Islands by the Coalition on Education Solomon Islands (COESI) in partnership with Asian South Pacific Bureau of Adult Education (ASPBAE). COESI aims to generate a reliable body of information that will: (1) Accurately explain how much the national government has done and can do to…

  9. The Solomon Islands tsunami of 6 February 2013 field survey in the Santa Cruz Islands

    NASA Astrophysics Data System (ADS)

    Fritz, H. M.; Papantoniou, A.; Biukoto, L.; Albert, G.

    2013-12-01

    On February 6, 2013 at 01:12:27 UTC (local time: UTC+11), a magnitude Mw 8.0 earthquake occurred 70 km to the west of Ndendo Island (Santa Cruz Island) in the Solomon Islands. The under-thrusting earthquake near a 90° bend, where the Australian plate subducts beneath the Pacific plate generated a locally focused tsunami in the Coral Sea and the South Pacific Ocean. The tsunami claimed the lives of 10 people and injured 15, destroyed 588 houses and partially damaged 478 houses, affecting 4,509 people in 1,066 households corresponding to an estimated 37% of the population of Santa Cruz Island. A multi-disciplinary international tsunami survey team (ITST) was deployed within days of the event to document flow depths, runup heights, inundation distances, sediment and coral boulder depositions, land level changes, damage patterns at various scales, performance of the man-made infrastructure and impact on the natural environment. The 19 to 23 February 2013 ITST covered 30 locations on 4 Islands: Ndendo (Santa Cruz), Tomotu Noi (Lord Howe), Nea Tomotu (Trevanion, Malo) and Tinakula. The reconnaissance completely circling Ndendo and Tinakula logged 240 km by small boat and additionally covered 20 km of Ndendo's hard hit western coastline by vehicle. The collected survey data includes more than 80 tsunami runup and flow depth measurements. The tsunami impact peaked at Manoputi on Ndendo's densely populated west coast with maximum tsunami height exceeding 11 m and local flow depths above ground exceeding 7 m. A fast tide-like positive amplitude of 1 m was recorded at Lata wharf inside Graciosa Bay on Ndendo Island and misleadingly reported in the media as representative tsunami height. The stark contrast between the field observations on exposed coastlines and the Lata tide gauge recording highlights the importance of rapid tsunami reconnaissance surveys. Inundation distance and damage more than 500 m inland were recorded at Lata airport on Ndendo Island. Landslides were

  10. Corals persisting in naturally turbid waters adjacent to a pristine catchment in Solomon Islands.

    PubMed

    Albert, Simon; Fisher, Paul L; Gibbes, Badin; Grinham, Alistair

    2015-05-15

    Few water quality measurements exist from pristine environments, with fewer reported studies of coastal water quality from Solomon Islands. Water quality benchmarks for the Solomons have relied on data from other geographic regions, often from quite different higher latitude developed nations, with large land masses. We present the first data of inshore turbidity and sedimentation rate for a pristine catchment on Isabel Island. Surveys recorded relatively high coral cover. The lowest cover was recorded at 22.7% (Jejevo) despite this site having a mean turbidity (continuous monitoring) of 32 NTU. However, a similar site (Jihro) was significantly less turbid (2.1 mean NTU) over the same period. This difference in turbidity is likely due to natural features of the Jihro River promoting sedimentation before reaching coastal sites. We provide an important baseline for Solomon Island inshore systems, whilst demonstrating the importance of continuous monitoring to capture episodic high turbidity events. PMID:25752531

  11. Prevalence of sexually transmitted infections in female clinic attendees in Honiara, Solomon Islands

    PubMed Central

    Kako, H; Butcher, R; Lauri, B; Puiahi, E; Pitakaka, R; Sokana, O; Kilua, G; Roth, A; Solomon, A W; Mabey, D C

    2015-01-01

    Objectives This study sought to determine the prevalence of common bacterial sexually transmitted infections, including Chlamydia trachomatis and Neisseria gonorrhoeae, in women attending clinics in the Solomon Islands. Methods We conducted a sexual health survey among women attending three nurse-led community outpatient clinics in August 2014, to establish the prevalence of bacterial sexually transmitted infections in female clinic attenders in Honiara, Solomon Islands. Vaginal swab samples were tested for infection with C. trachomatis and N. gonorrhoeae using a commercial strand displacement amplification assay. Serum samples were tested for syphilis. Results We enrolled 296 women, aged 16–49, attending three clinics. Knowledge of safe sexual practices was high but reported condom usage was low. The prevalence of infection with C. trachomatis was 20%. The prevalence of infection with N. gonorrhoeae and syphilis were 5.1% and 4.1%, respectively. Conclusions Bacterial sexually transmitted infections are a major health problem in the Solomon Islands. Interventions are urgently needed. PMID:25922103

  12. Muria Volcano, Island of Java, Indonesia

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This view of the north coast of central Java, Indonesia centers on the currently inactive Muria Volcano (6.5S, 111.0E). Muria is 5,330 ft. tall and lies just north of Java's main volcanic belt which runs east - west down the spine of the island attesting to the volcanic origin of the more than 1,500 Indonesian Islands.

  13. Baseline arsenic levels in marine and terrestrial resources from a pristine environment: Isabel Island, Solomon Islands.

    PubMed

    Grinham, Alistair; Kvennefors, Charlotte; Fisher, Paul L; Gibbes, Badin; Albert, Simon

    2014-11-15

    Baseline records are crucial in understanding how chemicals of concern impact on the receiving environment. We analysed terrestrial and marine resources from a pristine site on Isabel Island, Solomon Islands, to provide environmental baseline levels for total arsenic and arsenic species composition for commonly consumed marine resources. Our data show that levels of the more toxic inorganic arsenic species were very low or below detectable limits, with the exception of the seaweed Sargassum sp. that contained pentavalent inorganic arsenic levels of 4.63 μg g(-1). Total arsenic concentrations in the majority of marine and terrestrial samples collected were below 2 μg g(-1). The less toxic arsenobetaine was the predominant arsenic species present in all marine fauna samples analysed. This work highlights the need for arsenic speciation analysis to accurately assess potential toxicity of marine resources and provides a crucial baseline to assess the impact of future development within this region. PMID:25199709

  14. Baseline arsenic levels in marine and terrestrial resources from a pristine environment: Isabel Island, Solomon Islands.

    PubMed

    Grinham, Alistair; Kvennefors, Charlotte; Fisher, Paul L; Gibbes, Badin; Albert, Simon

    2014-11-15

    Baseline records are crucial in understanding how chemicals of concern impact on the receiving environment. We analysed terrestrial and marine resources from a pristine site on Isabel Island, Solomon Islands, to provide environmental baseline levels for total arsenic and arsenic species composition for commonly consumed marine resources. Our data show that levels of the more toxic inorganic arsenic species were very low or below detectable limits, with the exception of the seaweed Sargassum sp. that contained pentavalent inorganic arsenic levels of 4.63 μg g(-1). Total arsenic concentrations in the majority of marine and terrestrial samples collected were below 2 μg g(-1). The less toxic arsenobetaine was the predominant arsenic species present in all marine fauna samples analysed. This work highlights the need for arsenic speciation analysis to accurately assess potential toxicity of marine resources and provides a crucial baseline to assess the impact of future development within this region.

  15. Bridging near and remote Oceania: mtDNA and NRY variation in the Solomon Islands.

    PubMed

    Delfin, Frederick; Myles, Sean; Choi, Ying; Hughes, David; Illek, Robert; van Oven, Mannis; Pakendorf, Brigitte; Kayser, Manfred; Stoneking, Mark

    2012-02-01

    Although genetic studies have contributed greatly to our understanding of the colonization of Near and Remote Oceania, important gaps still exist. One such gap is the Solomon Islands, which extend between Bougainville and Vanuatu, thereby bridging Near and Remote Oceania, and include both Austronesian-speaking and Papuan-speaking groups. Here, we describe patterns of mitochondrial DNA (mtDNA) and nonrecombining Y chromosome (NRY) variation in over 700 individuals from 18 populations in the Solomons, including 11 Austronesian-speaking groups, 3 Papuan-speaking groups, and 4 Polynesian Outliers (descended via back migration from Polynesia). We find evidence for ancient (pre-Lapita) colonization of the Solomons in old NRY paragroups as well as from M2-M353, which probably arose in the Solomons ∼9,200 years ago and is the most frequent NRY haplogroup there. There are no consistent genetic differences between Austronesian-speaking and Papuan-speaking groups, suggesting extensive genetic contact between them. Santa Cruz, which is located in Remote Oceania, shows unusually low frequencies of mtDNA and NRY haplogroups of recent Asian ancestry. This is in apparent contradiction with expectations based on archaeological and linguistic evidence for an early (∼3,200 years ago), direct colonization of Santa Cruz by Lapita people from the Bismarck Archipelago, via a migration that "leapfrogged" over the rest of the Solomons. Polynesian Outliers show dramatic island-specific founder events involving various NRY haplogroups. We also find that NRY, but not mtDNA, genetic distance is correlated with the geographic distance between Solomons groups and that historically attested spheres of cultural interaction are associated with the recent genetic structure of Solomons groups, as revealed by mtDNA HV1 sequence and Y-STR haplotype diversity. Our results fill an important lacuna in human genetic studies of Oceania and aid in understanding the colonization and genetic history of

  16. Increased Rotavirus Prevalence in Diarrheal Outbreak Precipitated by Localized Flooding, Solomon Islands, 2014

    PubMed Central

    Jones, Forrest K.; Ko, Albert I.; Becha, Chris; Joshua, Cynthia; Musto, Jennie; Thomas, Sarah; Ronsse, Axelle; Kirkwood, Carl D.; Sio, Alison; Aumua, Audrey

    2016-01-01

    Flooding on 1 of the Solomon Islands precipitated a nationwide epidemic of diarrhea that spread to regions unaffected by flooding and caused >6,000 cases and 27 deaths. Rotavirus was identified in 38% of case-patients tested in the city with the most flooding. Outbreak potential related to weather reinforces the need for global rotavirus vaccination. PMID:27088272

  17. Solomon Islands Pijin: Culture and Communication Handbook. Peace Corps Language Handbook Series.

    ERIC Educational Resources Information Center

    Huebner, Thom; Horoi, Stephen Rex

    This handbook of the Pijin language is divided into four parts: (1) survival language skills, (2) situations in which the Peace Corps volunteer is likely to be involved, (3) getting the job done, and (4) information on the culture of the Solomon Islands. It establishes classroom activities that require the students to exchange messages in a way…

  18. The Impact of Church Affiliation on Language Use in Kwara'ae (Solomon Islands).

    ERIC Educational Resources Information Center

    Watson-Gegeo, Karen Ann; Gegeo, David Welchman

    1991-01-01

    The impact of church affiliation on language use, identity, and change among Kwara'ae speakers in the Solomon Islands is examined. It was found that members of different sects signal their separate identities not only through linguistic code but also through discourse patterns and nonverbal aspects of communication. (26 references) (JL)

  19. Influence of Schools on Economically Disadvantageous Attitudes: A Solomon Islands Study

    ERIC Educational Resources Information Center

    MacBeth, Alastair M.

    1976-01-01

    This study examines the economically detrimental attitude of regionalism in a Solomon Islands secondary school and measures changes in regionalism with exposure to school experience that stressed regional integration. Significant decreases in regionalism were recorded. (Available from Plenum Publishing Corporation, 227 West 17 Street, New York, NY…

  20. Building on Living Traditions: Early Childhood Education and Culture in Solomon Islands

    ERIC Educational Resources Information Center

    Burton, Lindsay J.

    2012-01-01

    The Solomon Islands, a small developing nation in the South Pacific, demonstrates an emerging community-based kindergarten model with the potential to promote context and culture relevant early learning and development, despite deeply embedded foundations in colonial legacies. Based on the Kahua region of Makira-Ulawa Province, this collaborative,…

  1. Keeping Culture Out of the Classroom in Rural Solomon Islands Schools: A Critical Analysis.

    ERIC Educational Resources Information Center

    Watson-Grego, Karen Ann; Grego, David W.

    1994-01-01

    Social and institutional factors in the Solomon Islands, shaped by colonialism and modernization, affect classroom practice, constraining teachers' use of cultural knowledge. The article challenges notions of cultural congruence as solutions to classroom problems, distinguishing between appropriation of childrens' culture for hegemonic interests…

  2. The Relationship between Early Childhood Education and Primary School Academic Achievement in Solomon Islands.

    ERIC Educational Resources Information Center

    Guild, Diana E.

    2000-01-01

    Examines the relationship between early childhood education and primary school academic achievement in the Solomon Islands. Notes factors influencing higher performance in reading comprehension and mathematics skills, and use of age appropriate materials. Offers insights for educators, policy planners, communities, and families. (JPB)

  3. Field survey of the Solomon Islands tsunami of 03 January 2010

    NASA Astrophysics Data System (ADS)

    Fritz, H. M.; Kalligeris, N.

    2010-05-01

    We will present results of the post-tsunami survey being conducted at the time of submission of the tsunami generated on 03 January 2010 by a large earthquake in the vicinity of the Woodlark-Australia-Pacific triple junction in the Solomon Islands, with significant damage reported in Rendova.

  4. Pijin at School in Solomon Islands: Language Ideologies and the Nation

    ERIC Educational Resources Information Center

    Jourdan, Christine

    2013-01-01

    In this article, I analyze the reasons that have excluded Pijin, the lingua franca of Solomon Islands, South West Pacific, from being used as a medium of instruction, and why this may now become possible. Following a short sociolinguistic sketch, I present the colonial and post-colonial linguistic ideologies that shaped sociolinguistic…

  5. "Engendering" environmental projects: the case of eco-timber production in the Solomon Islands.

    PubMed

    Scheyvens, R

    1998-11-01

    This article discusses the case of timber production in the Solomon Islands and links between environmental protection and gender. Many environmental projects are undertaken without regard for gender roles and relations. The Solomon Western Islands Fair Trade (SWIFT) initiative included women in only a peripheral way. This article justifies the involvement of women in environmental projects and then evaluates the operations of SWIFT. A role for women in local environmental projects should be recognized because of women's roles, knowledge, and interests. Use of natural resources is gender-based. In the Solomon Islands, women are identified as having the greater interest in the long-term sustainability of the environment and greater reliance on natural resources to fulfill their roles, but forestry is men's work. The price of tropical woods has tempted Micronesian governments to exploit forests to enhance their foreign exchange earnings. Environmental degradation from logging is particularly severe in the Solomon Islands. The population fulfills many basic needs from forests. Forests can provide cash earnings. The author conducted an evaluation of effectiveness of SWIFT in 1996. The SWIFT project allows rural people to earn cash from sustainable timber extraction without signing with logging companies. Women are affected by SWIFT due to their husbands' appropriation of their earnings, their peripheral role, and lack of representation in senior positions and use of women's forestry expertise. The article offers a model for genderizing eco-projects. Men need to be encouraged to work more as partners with women. PMID:12321992

  6. Increased Rotavirus Prevalence in Diarrheal Outbreak Precipitated by Localized Flooding, Solomon Islands, 2014.

    PubMed

    Jones, Forrest K; Ko, Albert I; Becha, Chris; Joshua, Cynthia; Musto, Jennie; Thomas, Sarah; Ronsse, Axelle; Kirkwood, Carl D; Sio, Alison; Aumua, Audrey; Nilles, Eric J

    2016-05-01

    Flooding on 1 of the Solomon Islands precipitated a nationwide epidemic of diarrhea that spread to regions unaffected by flooding and caused >6,000 cases and 27 deaths. Rotavirus was identified in 38% of case-patients tested in the city with the most flooding. Outbreak potential related to weather reinforces the need for global rotavirus vaccination. PMID:27088272

  7. Increased Rotavirus Prevalence in Diarrheal Outbreak Precipitated by Localized Flooding, Solomon Islands, 2014.

    PubMed

    Jones, Forrest K; Ko, Albert I; Becha, Chris; Joshua, Cynthia; Musto, Jennie; Thomas, Sarah; Ronsse, Axelle; Kirkwood, Carl D; Sio, Alison; Aumua, Audrey; Nilles, Eric J

    2016-05-01

    Flooding on 1 of the Solomon Islands precipitated a nationwide epidemic of diarrhea that spread to regions unaffected by flooding and caused >6,000 cases and 27 deaths. Rotavirus was identified in 38% of case-patients tested in the city with the most flooding. Outbreak potential related to weather reinforces the need for global rotavirus vaccination.

  8. Technical and Vocational Education and Training in Peace Education: Solomon Islands

    ERIC Educational Resources Information Center

    Maebuta, Jack

    2011-01-01

    Technical and vocational education and training programs as a form of peace education are examined in this paper. It explores the notion of educating for a culture of peace through refocusing technical and vocational education and training programs on sustainable community development in the Solomon Islands. It further highlights the policy and…

  9. "Engendering" environmental projects: the case of eco-timber production in the Solomon Islands.

    PubMed

    Scheyvens, R

    1998-11-01

    This article discusses the case of timber production in the Solomon Islands and links between environmental protection and gender. Many environmental projects are undertaken without regard for gender roles and relations. The Solomon Western Islands Fair Trade (SWIFT) initiative included women in only a peripheral way. This article justifies the involvement of women in environmental projects and then evaluates the operations of SWIFT. A role for women in local environmental projects should be recognized because of women's roles, knowledge, and interests. Use of natural resources is gender-based. In the Solomon Islands, women are identified as having the greater interest in the long-term sustainability of the environment and greater reliance on natural resources to fulfill their roles, but forestry is men's work. The price of tropical woods has tempted Micronesian governments to exploit forests to enhance their foreign exchange earnings. Environmental degradation from logging is particularly severe in the Solomon Islands. The population fulfills many basic needs from forests. Forests can provide cash earnings. The author conducted an evaluation of effectiveness of SWIFT in 1996. The SWIFT project allows rural people to earn cash from sustainable timber extraction without signing with logging companies. Women are affected by SWIFT due to their husbands' appropriation of their earnings, their peripheral role, and lack of representation in senior positions and use of women's forestry expertise. The article offers a model for genderizing eco-projects. Men need to be encouraged to work more as partners with women.

  10. "We can move forward": challenging historical inequity in public health research in Solomon Islands

    PubMed Central

    2010-01-01

    Background In resource-poor countries, such as Solomon Islands, the research agenda on health is often dominated by researchers from resource-rich countries. New strategies are needed to empower local researchers to set directions for health research. This paper presents a process which seeks to enable a local and potentially more equitable research agenda at a remote hospital in Solomon Islands. Methods In preparation for a health research capacity-building workshop at Atoifi Adventist Hospital, Malaita, Solomon Islands, a computer-based search was conducted of Solomon Islands public health literature. Using a levels-of-agreement approach publications were categorised as: a) original research, b) reviews, c) program descriptions and d) commentaries or discussion. Original research publications were further sub-categorised as: i) measurement, ii) descriptive research and iii) intervention studies. Results were reviewed with Solomon Islander health professionals in a focus group discussion during the health research workshop. Focus group participants were invited to discuss reactions to literature search results and how results might assist current or future local researchers to identify gaps in the published research literature and possible research opportunities at the hospital and surrounding communities. Focus group data were analysed using a grounded theory approach. Results Of the 218 publications meeting inclusion criteria, 144 (66%) were categorised as 'original research', 42 (19%) as 'commentaries/discussion', 28 (13%) as 'descriptions of programs' and 4 (2%) as 'reviews'. Agreement between three authors' (MRM, DM, AC) independent categorisation was 'excellent' (0.8 <κ). The 144 'original research' publications included 115 (80%) 'descriptive studies' (κ = 0.82); 19 (13%) 'intervention studies' (κ = 0.77); and 10 (7%) 'measurement studies'(κ = 0.80). Key themes identified in the focus group discussion challenged historical inequities evident from the

  11. Geochemistry and petrogenesis of the Gallego Volcanic Field, Solomon Islands, SW Pacific and geotectonic implications

    NASA Astrophysics Data System (ADS)

    Petterson, M. G.; Haldane, M. I.; Smith, D. J.; Billy, D.; Jordan, N. J.

    2011-08-01

    The Upper Miocene to present day Gallego Volcanic Field (GVF) is located in northwest Guadalcanal, Solomon Islands, SW Pacific, and potentially includes the offshore Savo volcano. The GVF is a multi-centred complex covering an area of ~ 800 km 2 on Guadalcanal and a further ~ 30 km 2 on the island of Savo, north of west Guadalcanal. GVF volcanism is characterised by effusive eruptions of lava, intrusion of sub-volcanic plutons, as well as pyroclastic flow and fall deposits dominated by block and ash flow deposits. Geochemical analysis of a representative suite of samples from the GVF demonstrates that the GVF comprise largely a 'main suite' of basalts to andesites and minor trachyandesites. The predominant mineralogy of the GVF comprises plagioclase, amphibole, clinopyroxene and magnetite-ilmenite. Associated with the 'main suite' are cognate nodules composed of hornblendite, gabbros, and clinopyroxenite. Interpretation of major and trace element geochemistry and petrographic studies suggests that fractionation was dominated by early clinopyroxene, and later amphibole + clinopyroxene + minor plagioclase. Geochemical features such as the incompatibility of Sr suggest that plagioclase largely crystallised en-masse late in the fractionation sequence. The presence of amphibole and late fractionation of plagioclase is suggestive of derivation from initially water-rich magmas. The region is characterised by strong geographically-related geochemical variations as evidenced by the Woodlark (and Manus) basins: basalts become more arc-like within the ocean basins with decreasing distance to the subducting trench. The GVF-Savo volcanoes are spatially and geochemically affected by deep N-S fractures that show some evidence of sympathetic geochemical variations with distance from the trench (e.g. Sr/Y ratios). Comparison with a range of international data for Th/Nb vs Pb/Nb and Dy/Yb vs SiO 2 indicate that: amphibole was indeed a strong controlling phase on magmatic evolution

  12. A new prenylflavonoid isolated from propolis collected in the Solomon Islands.

    PubMed

    Inui, Saori; Shimamura, Yuko; Masuda, Shuichi; Shirafuji, Kenichi; Moli, Reuben T; Kumazawa, Shigenori

    2012-01-01

    The new prenylflavonoid, solophenol A (1), together with three known compounds, bonannione A (2), sophoraflavanone A (3) and (2S)-5,7-dihydroxy-4'-methoxy-8-prenylflavanone (4), were isolated from propolis collected from Malaita Island in The Solomon Islands. The structure of each compound was determined by spectroscopic methods, including mass spectrometry and 2D NMR. Compound 1 exhibited potent 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity. PMID:22738984

  13. Source Models and Near-Field Impact of the 1 April 2007 Solomon Islands Tsunami

    NASA Astrophysics Data System (ADS)

    Wei, Yong; Fritz, Hermann M.; Titov, Vasily V.; Uslu, Burak; Chamberlin, Chris; Kalligeris, Nikos

    2015-03-01

    Within weeks of the Solomon Islands earthquake of 1 April 2007, international tsunami survey teams discovered important biomarkers of crust rupture and tsunami heights along the islands' coastlines. Deep-ocean tsunameters recorded the tsunami waves of this event, enabling a real-time inversion of the tsunami source and model evaluation of near-field tsunami impact. The survey measurements provide valuable datasets for further confirmation of the tsunami source of the 1 April 2007 Solomon earthquake. These survey results also aided investigation of the correlation between sources determined by use of tsunameter records and those derived from seismometer records or crust-rupture measurements. In this study, to assess the near-field tsunami impact, we developed tsunami inundation models for the Solomon Islands, including tsunami waveforms, co-seismic land-level changes, and tsunami height distributions on individual islands. Compared with seismic-derived tsunami sources, modeling results based on the tsunameter-derived tsunami sources were a good match with field survey measurements. These results highlight the accuracy and efficiency of the tsunameter-derived tsunami source in modeling the near-field tsunami impact along a complex archipelago. We show that the source models, although derived by use of different methods, are all suited to initiation of inundation models developed for Solomon Islands. As these source models become available in real time or near real time, they can be implemented immediately in the inundation models to provide rapid guidance on tsunami hazard assessment, focused search and rescue operations, and post-event recovery and reconstruction.

  14. Well-nourished women in a Solomon Islands society with a biased sex ratio.

    PubMed

    Furusawa, Takuro; Aswani, Shankar

    2011-03-01

    This study reports on the growth and nutritional status of females in Roviana (population 12 235), Solomon Islands, where there are fewer surviving females than males in all age groups (male/female = 1.10; Solomon Islands Government 2000). Anthropometric measurements were performed for 1243 voluntary participants from seven villages. The results showed that females were better nourished than males; weight-forage z-scores, for instance, were better for females than those for males throughout all age groups, with statistical significance in the following age groups: younger than 5 years, 10-14 years and 15-19 years. The same pattern was also observed for adults. Results suggest that gender inequality might not be caused by social discrimination. PMID:23008972

  15. Molecular analysis of glucose-6-phosphate dehydrogenase variants in the Solomon Islands

    SciTech Connect

    Hirono, A.; Ishii, A.; Hirono, K.; Miwa, S.; Kere, N.; Fujii, H.

    1995-05-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most prevalent genetic disorders, and >100 million people are considered to have mutant genes. G6PD deficiency is frequent in the area where plasmodium falciparum infection is endemic, probably because the G6PD-deficient subjects are resistant to the parasite. Falciparum and vivax malarias have been highly endemic in the Solomon Islands, and a high frequency of G6PD deficiency has also been expected. A recent investigation showed that the frequency of G6PD deficiency in the Solomon Islands was 8.4%-14.4%. Although >80 G6PD variants from various populations have been molecularly analyzed, little is known about those in Melanesians. G6PD Maewo, which was originally found in Vanuatu, has so far been the only Melanesian variant whose structural abnormality was determined. 14 refs., 1 fig.

  16. Characteristics of occult hepatitis B virus infection in the Solomon Islands.

    PubMed

    Utsumi, Takako; Yano, Yoshihiko; Truong, Bui Xuan; Kawabata, Masato; Hayashi, Yoshitake

    2011-06-01

    Hepatitis B virus (HBV) infection is highly endemic in the Solomon Islands. However, little is known about the status of occult HBV infection in the Solomon Islands. This study aimed to investigate the prevalence of occult HBV infection and its clinical and virological features in the community of Solomon Islands. Blood samples were collected from a total of 564 asymptomatic individuals aged over 18 years in the Western province. The samples used in the present study consisted of 200 samples from 108 males and 92 females (mean age, 37.4 years; range, 18-71 years) that were randomly selected among the hepatitis B surface antigen (HBsAg)-negative samples from all the participants enrolled in this study. HBV-DNA was detected by real-time PCR in 25 (12.5%) of the 200 HBsAg-negative samples. Most of the HBV-DNA-positive individuals were infected with wild-type HBV, and only 3 strains demonstrated specific amino acid substitutions (P121X, T123N, C138S, P142S and D144E) in the α determinant region. In conclusion, occult HBV infection was documented in 12.5% of individuals that demonstrated serologic evidence of resolved HBV infection in this study. The prevalence of occult infection was also influenced by ethnicity; it was more prevalent in Melanesians than Micronesians. In addition, occult HBV infection demonstrated a weak association with the S-variants. PMID:21455562

  17. Interactions between sea-level rise and wave exposure on reef island dynamics in the Solomon Islands

    NASA Astrophysics Data System (ADS)

    Albert, Simon; Leon, Javier X.; Grinham, Alistair R.; Church, John A.; Gibbes, Badin R.; Woodroffe, Colin D.

    2016-05-01

    Low-lying reef islands in the Solomon Islands provide a valuable window into the future impacts of global sea-level rise. Sea-level rise has been predicted to cause widespread erosion and inundation of low-lying atolls in the central Pacific. However, the limited research on reef islands in the western Pacific indicates the majority of shoreline changes and inundation to date result from extreme events, seawalls and inappropriate development rather than sea-level rise alone. Here, we present the first analysis of coastal dynamics from a sea-level rise hotspot in the Solomon Islands. Using time series aerial and satellite imagery from 1947 to 2014 of 33 islands, along with historical insight from local knowledge, we have identified five vegetated reef islands that have vanished over this time period and a further six islands experiencing severe shoreline recession. Shoreline recession at two sites has destroyed villages that have existed since at least 1935, leading to community relocations. Rates of shoreline recession are substantially higher in areas exposed to high wave energy, indicating a synergistic interaction between sea-level rise and waves. Understanding these local factors that increase the susceptibility of islands to coastal erosion is critical to guide adaptation responses for these remote Pacific communities.

  18. Island arc picrites from the solomon islands - origin by mantle matrix collapse

    NASA Astrophysics Data System (ADS)

    Rohrbach, A.; Schuth, S.; Münker, C.; Ballhaus, C.

    2003-04-01

    The MgO enrichment in picrites is commonly explained by accumulation of liquidus olivine in a convecting magma chamber. Here we report results from subduction related picrites from the New Georgia archipelago (Solomon Islands) that were examined to derive the parental melt composition and to understand the wide range in MgO contents (13 to 30 wt.%). The New Georgia picrites cannot be explained by a simple cumulate assimilation model. The samples contain up to 40 vol.% olivine, calcic cpx, and chrome spinel as phenocrysts, set in a microcrystalline groundmass. There are two distinct populations of olivine, one with <0.12 wt.% CaO (low--Ca) and one with 0.18 to 0.34 wt.% CaO (high--Ca). The high--Ca olivines (Fo84-92) are considered to be the equilibrium olivine phenocrysts of a basaltic to picritic melt. The low--Ca olivines (Fo90-93.4) zone towards high--Ca compositions towards the rims and were obviously not in equilibrium with the melt at the time of crystal incorporation. Oxygen fugacities of the picrites calculated from Fe3+ in chrome spinel are around FMQ+3.35. At this relative fO_2 the MgO content of the parent melt is constrained to 14.85 wt.% assuming Kolv-liqDFe-Mg equilibrium (0.3) with the high--Ca olivines. The liquidus temperature of the melt [1] based on this MgO content is 1323^oC, 60^oC above the olivine--cpx Ca--exchange temperature [2]. The depth of melting is constrained to less than 60 km by the seismic depth of the Benioff zone. This is also supported by geochemistry [3] and the highly oxidized nature of the parent melt that favour the mantle wedge as the exclusive mantle source. The presence of picrites in the Solomon Islands is confined to the region above the active Woodlark spreading centre that is subducted beneath the arc. This extra heat source caused extensive melting and an eventual collapse of the mantle matrix, represented by the assimilated low--Ca olivines. The range in bulk MgO is almost entirely controlled by assimilation of

  19. Checklist of the ants (Hymenoptera, Formicidae) of the Solomon Islands and a new survey of Makira Island.

    PubMed

    Sarnat, Eli M; Blanchard, Benjamin; Guénard, Benoit; John Fasi; Evan P Economo

    2013-01-01

    The intent of this paper is to facilitate future research of the Solomon Islands ant fauna by providing the first comprehensively researched species inventory in over 75 years. The species list presented here includes the names of all ant species recorded from the islands that are available in the literature together with specimen records from several museum collections and new records from our 2008 Makira field expedition. All the names of described species presented are valid in accordance with the most recent Formicidae classification. In total, the checklist is composed of 237 species and subspecies (including 30 morphospecies) in 59 genera representing nine subfamilies. We report that the recent field expedition added 67 new species records to Makira and 28 new species records to the Solomon Islands. Our research recovered species occurrence records for 32 individual islands and five island groups. The five islands with the highest number of recorded species are: Makira (142 spp.), Guadalcanal (107 spp.), Malaita (70 spp.), Santa Isabel (68 spp.), and Rennell (66 spp.). Based on our results, we discuss the taxonomic composition of the archipelago's ant fauna, which islands are most in need of additional sampling, and the importance of establishing biodiversity baselines before environmental threats such as the invasive ant Wasmannia auropunctata cause irrevocable harm to the native biodiversity. PMID:23653494

  20. Checklist of the ants (Hymenoptera, Formicidae) of the Solomon Islands and a new survey of Makira Island.

    PubMed

    Sarnat, Eli M; Blanchard, Benjamin; Guénard, Benoit; John Fasi; Evan P Economo

    2013-01-01

    The intent of this paper is to facilitate future research of the Solomon Islands ant fauna by providing the first comprehensively researched species inventory in over 75 years. The species list presented here includes the names of all ant species recorded from the islands that are available in the literature together with specimen records from several museum collections and new records from our 2008 Makira field expedition. All the names of described species presented are valid in accordance with the most recent Formicidae classification. In total, the checklist is composed of 237 species and subspecies (including 30 morphospecies) in 59 genera representing nine subfamilies. We report that the recent field expedition added 67 new species records to Makira and 28 new species records to the Solomon Islands. Our research recovered species occurrence records for 32 individual islands and five island groups. The five islands with the highest number of recorded species are: Makira (142 spp.), Guadalcanal (107 spp.), Malaita (70 spp.), Santa Isabel (68 spp.), and Rennell (66 spp.). Based on our results, we discuss the taxonomic composition of the archipelago's ant fauna, which islands are most in need of additional sampling, and the importance of establishing biodiversity baselines before environmental threats such as the invasive ant Wasmannia auropunctata cause irrevocable harm to the native biodiversity.

  1. Checklist of the ants (Hymenoptera, Formicidae) of the Solomon Islands and a new survey of Makira Island

    PubMed Central

    Sarnat, Eli M.; Blanchard, Benjamin; Guénard, Benoit; John Fasi;  Evan P. Economo

    2013-01-01

    Abstract The intent of this paper is to facilitate future research of the Solomon Islands ant fauna by providing the first comprehensively researched species inventory in over 75 years. The species list presented here includes the names of all ant species recorded from the islands that are available in the literature together with specimen records from several museum collections and new records from our 2008 Makira field expedition. All the names of described species presented are valid in accordance with the most recent Formicidae classification. In total, the checklist is composed of 237 species and subspecies (including 30 morphospecies) in 59 genera representing nine subfamilies. We report that the recent field expedition added 67 new species records to Makira and 28 new species records to the Solomon Islands. Our research recovered species occurrence records for 32 individual islands and five island groups. The five islands with the highest number of recorded species are: Makira (142 spp.), Guadalcanal (107 spp.), Malaita (70 spp.), Santa Isabel (68 spp.), and Rennell (66 spp.). Based on our results, we discuss the taxonomic composition of the archipelago’s ant fauna, which islands are most in need of additional sampling, and the importance of establishing biodiversity baselines before environmental threats such as the invasive ant Wasmannia auropunctata cause irrevocable harm to the native biodiversity. PMID:23653494

  2. Ancestral heritage saves tribes during 1 April 2007 Solomon Islands tsunami

    NASA Astrophysics Data System (ADS)

    Fritz, Hermann M.; Kalligeris, Nikos

    2008-01-01

    The 1 April 2007 magnitude Ms 8.1 earthquake off the New Georgia Group in the Solomon Islands generated a tsunami that killed 52 with locally focused run-up heights of 12 m, local flow depths of 5 m as well as tectonic uplift up to 3.6 m and subsidence down to -1.5 m. A reconnaissance team deployed within one week investigated 65 coastal settlements on 13 remote Islands. The ancestral heritage ``run to high ground after an earthquake'' passed on to younger generations by survivors of smaller historic tsunamis triggered an immediate spontaneous self evacuation containing the death toll.

  3. Solomon Islands 2007 Tsunami Near-Field Modeling and Source Earthquake Deformation

    NASA Astrophysics Data System (ADS)

    Uslu, B.; Wei, Y.; Fritz, H.; Titov, V.; Chamberlin, C.

    2008-12-01

    The earthquake of 1 April 2007 left behind momentous footages of crust rupture and tsunami impact along the coastline of Solomon Islands (Fritz and Kalligeris, 2008; Taylor et al., 2008; McAdoo et al., 2008; PARI, 2008), while the undisturbed tsunami signals were also recorded at nearby deep-ocean tsunameters and coastal tide stations. These multi-dimensional measurements provide valuable datasets to tackle the challenging aspects at the tsunami source directly by inversion from tsunameter records in real time (available in a time frame of minutes), and its relationship with the seismic source derived either from the seismometer records (available in a time frame of hours or days) or from the crust rupture measurements (available in a time frame of months or years). The tsunami measurements in the near field, including the complex vertical crust motion and tsunami runup, are particularly critical to help interpreting the tsunami source. This study develops high-resolution inundation models for the Solomon Islands to compute the near-field tsunami impact. Using these models, this research compares the tsunameter-derived tsunami source with the seismic-derived earthquake sources from comprehensive perceptions, including vertical uplift and subsidence, tsunami runup heights and their distributional pattern among the islands, deep-ocean tsunameter measurements, and near- and far-field tide gauge records. The present study stresses the significance of the tsunami magnitude, source location, bathymetry and topography in accurately modeling the generation, propagation and inundation of the tsunami waves. This study highlights the accuracy and efficiency of the tsunameter-derived tsunami source in modeling the near-field tsunami impact. As the high- resolution models developed in this study will become part of NOAA's tsunami forecast system, these results also suggest expanding the system for potential applications in tsunami hazard assessment, search and rescue operations

  4. Near-Field Population Response During the 2 April 2007 Solomon Islands Tsunami

    NASA Astrophysics Data System (ADS)

    McAdoo, B. G.; Moore, A. L.; Baumwoll, J.

    2007-12-01

    When the magnitude 8.1 earthquake and subsequent tsunami hit the Solomon Islands on 2 April 2007 it killed 52 people. On Ghizo Island, home of the capital of the Western Province, Gizo, waves approaching 4 m in height inundated the south coast villages. Eyewitness accounts supported by geologic data from the offshore coral reef and sediment deposited on land suggest a wave that came in as the shaking stopped as a rapidly-rising tide rather than a turbulent bore- vehicles and houses were floated inland with very little damage. Those that survived in villages affected by the tsunami had indigenous knowledge of prior events, whereas immigrant populations died in higher proportions. While buoy-based early warning systems are necessary to mitigate the effects of teletsunamis, they would have done little good in this near-field environment. In Pailongge, a village of 76 indigenous Solomon Islanders on Ghizo's south coast, there were no deaths. Village elders directed the people inland following the shaking and the almost immediate withdrawal of water from the lagoon, and heads of household made sure that children were accounted for and evacuated. Of the 366 Gilbertese living in Titiana, however, 13 people died, 8 of which were children who were exploring the emptied lagoon. A large proportion of the dead were children (24) as they were likely too weak to swim against the non-bore flow. The Gilbertese migrated from Kiribati in the 1950"s, and had not experienced a major earthquake and tsunami, hence had no cultural memory. In the case of the Solomon Islands tsunami, as was the case in the 2004 Indian Ocean tsunami, indigenous knowledge served the people in the near-field well. In the case of the Indian Ocean where there was 10-20 minutes separation between the time the shaking began and the waves arrived, the combination of an in-place plan and a suitable physical geography allowed the population of Simeulue Island and the Moken people of Thailand to escape before the

  5. Living on Active Volcanoes - The Island of Hawai'i

    USGS Publications Warehouse

    Heliker, Christina; Stauffer, Peter H.; Hendley, James W.

    1997-01-01

    People on the Island of Hawai'i face many hazards that come with living on or near active volcanoes. These include lava flows, explosive eruptions, volcanic smog, damaging earthquakes, and tsunamis (giant seawaves). As the population of the island grows, the task of reducing the risk from volcano hazards becomes increasingly difficult. To help protect lives and property, U.S. Geological Survey (USGS) scientists at the Hawaiian Volcano Observatory closely monitor and study Hawai'i's volcanoes and issue timely warnings of hazardous activity.

  6. Regional offshore geology of central and western Solomon Islands and Bougainville, Papua New Guinea

    SciTech Connect

    Vedder, J.G.; Colwell, J.B.; Bruns, T.R.; Cooper, A.K.

    1986-07-01

    The central and western Solomon Islands and the Bougainville regions are parts of a complex island-arc system that includes an intra-arc basin and remnants of both forearc and back-arc depositional wedges. These features formed in response to episodic Cenozoic tectonism along the convergent boundary between the Pacific and Australia-India plates. Presumed early Tertiary southwest-directed subduction of the Pacific plate and associated arc magmatism were curtailed by impingement of the leading edge of the Ontong Java Plateau. Aprons of back-arc and forearc sediment were derived from highstanding parts of the arc during the late Oligocene and early Miocene. Late Tertiary arc-polarity reversal and northeastward-directed subduction of the Woodlark spreading system caused a renewal of island-arc magmatism that completed the construction of the Central Solomons Trough as an enclosed intra-arc basin. Interpretations of multichannel profiles from 1982 and 1984 CCOP/SOPAC Tripartite Cruises of the research vessel R/V S.P. Lee indicate that the Central Solomons Trough is a composite intra-arc basin containing as much as 5.5 km of late Oligocene(.) and younger sedimentary rocks. As many as five lenticular seismic-stratigraphic units can be identified on the basis of unconformities and abrupt velocity changes. Late Miocene and younger folds and faults deform the northeast and southwest flanks of the basin. Profiles across the Kilinailau Trench show Ontong Java Plateau rocks covered by 2-4 km of trench sediment. The inner trench wall consists of folded, upfaulted, and rotated blocks of trench and forearc strata. The deep-water basin northwest of Bougainville is a southeastward extension of the New Ireland forearc basin, the southern margin of which is formed by a subsided part of the early Cenozoic arc. There, Oligocene(.) and younger basin strata, as much as 7 km thick, are deformed by pre-Pliocene faults and folds.

  7. An outbreak investigation of scrub typhus in Western Province, Solomon Islands, 2014

    PubMed Central

    Marks, Michael; Joshua, Cynthia; Longbottom, Jenny; Longbottom, Katherine; Sio, Alison; Puiahi, Elliot; Jilini, Greg; Stenos, John; Dalipanda, Tenneth

    2016-01-01

    Objective To identify the etiology and risk factors of undifferentiated fever in a cluster of patients in Western Province, Solomon Islands, May 2014. Methods An outbreak investigation with a case control study was conducted. A case was defined as an inpatient in one hospital in Western Province, Solomon Islands with high fever (> 38.5 °C) and a negative malaria microscopy test admitted between 1 and 31 May 2014. Asymptomatic controls matched with the cases residentially were recruited in a ratio of 1:2. Serum samples from the subjects were tested for rickettsial infections using indirect micro-immunofluorescence assay. Results Nine cases met the outbreak case definition. All cases were male. An eschar was noted in five cases (55%), and one developed pneumonitis. We did not identify any environmental factors associated with illness. Serum samples of all five follow-up cases (100%) had strong-positive IgG responses to scrub typhus. All but one control (10%) had a moderate response against scrub typhus. Four controls had low levels of antibodies against spotted fever group rickettsia, and only one had a low-level response to typhus group rickettsia. Discussion This outbreak represents the first laboratory-confirmed outbreak of scrub typhus in the Western Province of Solomon Islands. The results suggest that rickettsial infections are more common than currently recognized as a cause of an acute febrile illness. A revised clinical case definition for rickettsial infections and treatment guidelines were developed and shared with provincial health staff for better surveillance and response to future outbreaks of a similar kind.

  8. Child health nurses in the Solomon Islands: lessons for the Pacific and other developing countries

    PubMed Central

    2012-01-01

    Objectives To understand the roles of nurses with advanced training in paediatrics in the Solomon Islands, and the importance of these roles to child health. To understand how adequately equipped child health nurses feel for these roles, to identify the training needs, difficulties and future opportunities. Design Semi-structured interviews. Settings Tertiary hospital, district hospitals and health clinics in the Solomon Islands. Participants Twenty-one paediatric nurses were interviewed out of a total of 27 in the country. Results All nurses were currently employed in teaching, clinical or management areas. At least one or two nurses were working in each of 7 of the 9 provinces; in the two smaller provinces there were none. Many nurses were sole practitioners in remote locations without back-up from doctors or other experienced nurses; all had additional administrative or public health duties. Different types of courses were identified: a residential diploma through the University of Papua New Guinea or New Zealand and a diploma by correspondence through the University of Sydney. Conclusions Child health nurses in the Solomon Islands fulfill vital clinical, public health, teaching and administrative roles. Currently they are too few in number, and this is a limiting factor for improving the quality of child health services in that country. Current methods of training require overseas travel, or are expensive, or lack relevance, or remove nurses from their work-places and families for prolonged periods of time. A local post-basic child health nursing course is urgently needed, and models exist to achieve this. PMID:23171144

  9. Prevalence of soil-transmitted helminths in remote villages in East Kwaio, Solomon Islands

    PubMed Central

    Harrington, Humpress; Bradbury, Richard; Taeka, James; Asugeni, James; Asugeni, Vunivesi; Igeni, Tony; Gwala, John; Newton, Lawrence; Fa, Chillion Evan; Kilivisi, Fawcett Laurence; Esau, Dorothy; Flores, Angelica; Ribeyro, Elmer; Liku, Daisy; Muse, Alwin; Asugeni, Lyndel; Talana, Jeptha; Shield, Jennifer; MacLaren, David J; Massey, Peter D; Muller, Reinhold

    2015-01-01

    Objective Although soil-transmitted helminths (STH) are endemic in Solomon Islands, there are few recent reports on their prevalence. This study aimed to determine the prevalence of STH in residents of remote communities in Solomon Islands. Methods A cross-sectional convenience-sampled survey of residents of four adjacent villages in Malaita, Solomon Islands was performed in Atoifi and Na’au in April 2011 and in Abitona and Sifilo in April 2012. All residents older than one year were invited to participate, which involved providing a single sample of faeces examined using a modified Kato-Katz technique and completing a questionnaire that asked demographic and STH-related behaviour questions. Results The overall participation rate was 52.8%, with 402 participants comprising 49.8% males. Hookworm was the predominant STH with only a single case of trichuriasis found in Atoifi. The total prevalence of hookworm was 22.6% (95% confidence interval: 18.6–27.1); the prevalence of hookworm in Abitona, Na’au and Sifilo was 20.0%, 29.9% and 27.4%, respectively, whereas in Atoifi it was 2.3% (P < 0.001). Intensity was low in all villages. Although health behaviours differed significantly between Atoifi and the other three villages, the type of toilet used was the only significant association with hookworm. Discussion Residents of Atoifi have a relative freedom from STH compared to the other three villages. Rather than a region-wide morbidity control approach, a “one village at a time” approach aiming to eliminate STH and dealing with each village as a separate autonomous unit empowered to manage its own challenges may be a preferred option. PMID:26668767

  10. Measuring maternal mortality in developing Pacific island countries: experience with the sisterhood method in the Solomon Islands.

    PubMed

    O'Brien, J; Wierzba, T; Knott, S; Pikacha, J

    1994-07-13

    The aim was to estimate the maternal mortality rate in the Solomon Islands and to assist health planning in the implementation of effective interventions. In many Pacific Island countries, registration of deaths is inaccurate and incomplete. The survey in the Solomon Islands was conducted in June 1992, and 2580 randomly chosen women were interviewed using the standard World Health Organization cluster sampling technique. The sisterhood method, an indirect technique for deriving population-based estimates of maternal mortality, was used in interviews reporting on the fertility and mortality experience of subjects' sisters. The sisterhood method was developed at the London School of Hygiene and Tropical Medicine in 1987 as an indirect technique for deriving population-based estimates of maternal mortality. In order to calculate the proportions of sisters dying of maternal causes, 4 questions were asked about deaths of their sisters 15 years of age or over during pregnancy, delivery or the puerperium. These, together with the 5-year age group of the respondents, formed the basic data for deriving an estimate of maternal mortality. An overall estimate of lifetime risk of maternal death across all respondent age groups was derived by dividing the total reported maternal deaths by the sum of the units of risk exposure across all age groups (73/2227 = 0.033) or a lifetime risk of 1 in 30. Through a series of well-defined mathematical calculations, it was possible to convert the information into retrospective estimates of maternal mortality. The maternal mortality ratio in this study was 549/100,000 (95% CI 431, 684), equivalent to 1 maternal death in every 180 pregnancies. The sisterhood method was found to be easy to administer, inexpensive, and quick, and is recommended as a measurement tool to other developing countries. The publication of the results has prompted the government of the Solomon Islands to act. PMID:8022583

  11. Health impacts of climate change in the Solomon Islands: an assessment and adaptation action plan.

    PubMed

    Spickett, Jeffery T; Katscherian, Dianne

    2014-09-01

    The Pacific island countries are particularly vulnerable to the environmental changes wrought by global climate change such as sea level rise, more frequent and intense extreme weather events and increasing temperatures. The potential biophysical changes likely to affect these countries have been identified and it is important that consideration be given to the implications of these changes on the health of their citizens. The potential health impacts of climatic changes on the population of the Solomon Islands were assessed through the use of a Health Impact Assessment framework. The process used a collaborative and consultative approach with local experts to identify the impacts to health that could arise from local environmental changes, considered the risks associated with these and proposed appropriate potential adaptive responses. Participants included knowledgeable representatives from the biophysical, socio-economic, infrastructure, environmental diseases and food sectors. The risk assessments considered both the likelihood and consequences of the health impacts occurring using a qualitative process. To mitigate the adverse effects of the health impacts, an extensive range of potential adaptation strategies were developed. The overall process provided an approach that could be used for further assessments as well as an extensive range of responses which could be used by sectors and to assist future decision making associated with the Solomon Islands' responses to climate change. PMID:25168977

  12. Health impacts of climate change in the Solomon Islands: an assessment and adaptation action plan.

    PubMed

    Spickett, Jeffery T; Katscherian, Dianne

    2014-06-25

    The Pacific island countries are particularly vulnerable to the environmental changes wrought by global climate change such as sea level rise, more frequent and intense extreme weather events and increasing temperatures. The potential biophysical changes likely to affect these countries have been identified and it is important that consideration be given to the implications of these changes on the health of their citizens. The potential health impacts of climatic changes on the population of the Solomon Islands were assessed through the use of a Health Impact Assessment framework. The process used a collaborative and consultative approach with local experts to identify the impacts to health that could arise from local environmental changes, considered the risks associated with these and proposed appropriate potential adaptive responses. Participants included knowledgeable representatives from the biophysical, socio-economic, infrastructure, environmental diseases and food sectors. The risk assessments considered both the likelihood and consequences of the health impacts occurring using a qualitative process. To mitigate the adverse effects of the health impacts, an extensive range of potential adaptation strategies were developed. The overall process provided an approach that could be used for further assessments as well as an extensive range of responses which could be used by sectors and to assist future decision making associated with the Solomon Islands' responses to climate change.

  13. Arc segmentation and seismicity in the Solomon Islands arc, SW Pacific

    NASA Astrophysics Data System (ADS)

    Chen, Ming-Chu; Frohlich, Cliff; Taylor, Frederick W.; Burr, George; van Ufford, Andrew Quarles

    2011-07-01

    This paper evaluates neotectonic segmentation in the Solomon Islands forearc, and considers how it relates to regional tectonic evolution and the extent of ruptures of large megathrust earthquakes. We first consider regional geomorphology and Quaternary vertical displacements, especially uplifted coral reef terraces. Then we consider geographic seismicity patterns, aftershock areas and vertical displacements for large earthquakes, focal mechanisms, and along-arc variations in seismic moment release to evaluate the relationship between neotectonically defined segments and seismicity. Notably, one major limitation of using seismicity to evaluate arc segmentation is the matter of accurately defining earthquake rupture zones. For example, shoreline uplifts associated with the 1 April 2007 M w 8.1 Western Solomons earthquake indicate that the along-arc extent of rupture was about 50 km smaller than the aftershock area. Thus if we had relied on aftershocks alone to identify the 2007 rupture zone, as we do for most historical earthquakes, we would have missed the rupture's relationship to a major morphologic feature. In many cases, the imprecision of defining rupture zones without surface deformation data may be largely responsible for the poor mismatches to neotectonic boundaries. However, when a precise paleoseismic vertical deformation history is absent, aftershocks are often the best available tool for inferring rupture geometries. Altogether we identify 16 segments in the Solomon Islands. These comprise three major tectonic regimes or supersegments that correspond respectively to the forearc areas of Guadalcanal-Makira, the New Georgia island group, and Bougainville Islands. Subduction of the young and relatively shallow and buoyant Woodlark Basin and spreading system distinguishes the central New Georgia supersegment from the two neighboring supersegments. The physiographic expression of the San Cristobal trench is largely absent, but bathymetric mapping of the

  14. Tsunami Field Survey for the Solomon Islands Earthquake of April 1, 2007

    NASA Astrophysics Data System (ADS)

    Nishimura, Y.; Tanioka, Y.; Nakamura, Y.; Tsuji, Y.; Namegaya, Y.; Murata, M.; Woodward, S.

    2007-12-01

    Two weeks after the 2007 off-Solomon earthquake, an international tsunami survey team (ITST) of Japanese and US researchers performed a post tsunami survey in Ghizo and adjacent islands. Main purpose of the team was to provide information on the earthquake and tsunami to the national disaster council of the Solomon Islands, who was responsible for the disaster management at that time. The ITST had interview with the affected people and conducted reconnaissance mapping of the tsunami heights and flow directions. Tsunami flow heights at beach and inland were evaluated from watermarks on buildings and the position of broken branches and stuck materials on trees. These tsunami heights along the southern to western coasts of Ghizo Island were ca. 5m (a.s.l.). Tsunami run-up was traced by distribution of floating debris that carried up by the tsunami and deposited at their inundation limit. The maximum run-up was measured at Tapurai of Simbo Island to be ca. 9 m. Most of the inundation area was covered by 0-10 cm thick tsunami deposit that consists of beach sand, coral peaces and eroded soil. Coseismic uplift and subsidence were clearly identified by changes of the sea level before and after the earthquake, that were inferred by eyewitness accounts and evidences such as dried up coral reeves. These deformation patterns, as well as the tsunami height distribution, could constrain the earthquake fault geometry and motion. It is worthy of mention that the tsunami damage in villages in Ranongga Island has significantly reduced by 2-3 m uplift before the tsunami attack.

  15. Coseismic vertical deformation during the great 2007 Solomon Islands megathrust rupture

    NASA Astrophysics Data System (ADS)

    Briggs, R.; Taylor, F. W.; Frohlich, C.; Papabatu, A. K.; Billy, D.; Brown, A.; Meltzner, A. J.

    2007-12-01

    A joint US-Solomon Islands team visited the epicentral area of the 1 April 2007 Mw 8.1 Solomon Islands earthquake a few weeks after the event. We used coral microatolls, satellite imagery, and displaced geomorphic and cultural features to map the coseismic deformation pattern in the region directly above and adjacent to the subduction megathrust rupture. Among our main findings is that most slip occurred on the shallow portion of the megathrust and that slip appears to have reached the deformation front at Ranongga island, which was uplifted as much as ~2.5 m when the rupture propagated across the subducting Simbo ridge transform. Simbo island, which sits on the downgoing Australian plate and lies only 8 km across the plate boundary from uplifted Ranongga, subsided ~0.7 m coseismically and experienced only subdued ground motions. The line of zero vertical displacement (hingeline) runs closely along the southwestern coasts of Vella Lavella, Ghizo, and Parara islands, implying a persistent structural relationship between the downdip limit of coseismic slip and these coastlines. A broad, asymmetrical subsidence trough as deep as ~0.7 m extends across Vella Lavella, Kolombangara, Parara, and New Georgia. Uplift of ~0.35 m on the westermost tip of Rendova, along with overall subsidence of Rendova and Tetepare, place a firm limit on the southeastern extent of rupture. Uplift of Mono and subsidence of Fauro and the Shortlands, and no resolvable vertical change on Bougainville, define a rupture length of nearly 250 km between Rendova and the Woodlark rise.

  16. Defining Population Health Vulnerability Following an Extreme Weather Event in an Urban Pacific Island Environment: Honiara, Solomon Islands.

    PubMed

    Natuzzi, Eileen S; Joshua, Cynthia; Shortus, Matthew; Reubin, Reginald; Dalipanda, Tenneth; Ferran, Karen; Aumua, Audrey; Brodine, Stephanie

    2016-08-01

    Extreme weather events are common and increasing in intensity in the southwestern Pacific region. Health impacts from cyclones and tropical storms cause acute injuries and infectious disease outbreaks. Defining population vulnerability to extreme weather events by examining a recent flood in Honiara, Solomon Islands, can help stakeholders and policymakers adapt development to reduce future threats. The acute and subacute health impacts following the April 2014 floods were defined using data obtained from hospitals and clinics, the Ministry of Health and in-country World Health Organization office in Honiara. Geographical information system (GIS) was used to assess morbidity and mortality, and vulnerability of the health system infrastructure and households in Honiara. The April flash floods were responsible for 21 acute deaths, 33 injuries, and a diarrhea outbreak that affected 8,584 people with 10 pediatric deaths. A GIS vulnerability assessment of the location of the health system infrastructure and households relative to rivers and the coastline identified 75% of the health infrastructure and over 29% of Honiara's population as vulnerable to future hydrological events. Honiara, Solomon Islands, is a rapidly growing, highly vulnerable urban Pacific Island environment. Evaluation of the mortality and morbidity from the April 2014 floods as well as the infectious disease outbreaks that followed allows public health specialists and policy makers to understand the health system and populations vulnerability to future shocks. Understanding the negative impacts natural disaster have on people living in urban Pacific environments will help the government as well as development partners in crafting resilient adaptation development. PMID:27091867

  17. Defining Population Health Vulnerability Following an Extreme Weather Event in an Urban Pacific Island Environment: Honiara, Solomon Islands.

    PubMed

    Natuzzi, Eileen S; Joshua, Cynthia; Shortus, Matthew; Reubin, Reginald; Dalipanda, Tenneth; Ferran, Karen; Aumua, Audrey; Brodine, Stephanie

    2016-08-01

    Extreme weather events are common and increasing in intensity in the southwestern Pacific region. Health impacts from cyclones and tropical storms cause acute injuries and infectious disease outbreaks. Defining population vulnerability to extreme weather events by examining a recent flood in Honiara, Solomon Islands, can help stakeholders and policymakers adapt development to reduce future threats. The acute and subacute health impacts following the April 2014 floods were defined using data obtained from hospitals and clinics, the Ministry of Health and in-country World Health Organization office in Honiara. Geographical information system (GIS) was used to assess morbidity and mortality, and vulnerability of the health system infrastructure and households in Honiara. The April flash floods were responsible for 21 acute deaths, 33 injuries, and a diarrhea outbreak that affected 8,584 people with 10 pediatric deaths. A GIS vulnerability assessment of the location of the health system infrastructure and households relative to rivers and the coastline identified 75% of the health infrastructure and over 29% of Honiara's population as vulnerable to future hydrological events. Honiara, Solomon Islands, is a rapidly growing, highly vulnerable urban Pacific Island environment. Evaluation of the mortality and morbidity from the April 2014 floods as well as the infectious disease outbreaks that followed allows public health specialists and policy makers to understand the health system and populations vulnerability to future shocks. Understanding the negative impacts natural disaster have on people living in urban Pacific environments will help the government as well as development partners in crafting resilient adaptation development.

  18. Health Impacts of Climate Change in the Solomon Islands: An Assessment and Adaptation Action Plan

    PubMed Central

    Spickett, Jeffery T; Katscherian, Dianne

    2014-01-01

    The Pacific island countries are particularly vulnerable to the environmental changes wrought by global climate change such as sea level rise, more frequent and intense extreme weather events and increasing temperatures. The potential biophysical changes likely to affect these countries have been identified and it is important that consideration be given to the implications of these changes on the health of their citizens. The potential health impacts of climatic changes on the population of the Solomon Islands were assessed through the use of a Health Impact Assessment framework. The process used a collaborative and consultative approach with local experts to identify the impacts to health that could arise from local environmental changes, considered the risks associated with these and proposed appropriate potential adaptive responses. Participants included knowledgeable representatives from the biophysical, socio-economic, infrastructure, environmental diseases and food sectors. The risk assessments considered both the likelihood and consequences of the health impacts occurring using a qualitative process. To mitigate the adverse effects of the health impacts, an extensive range of potential adaptation strategies were developed. The overall process provided an approach that could be used for further assessments as well as an extensive range of responses which could be used by sectors and to assist future decision making associated with the Solomon Islands’ responses to climate change. PMID:25168977

  19. Mapping the Epidemiology of Yaws in the Solomon Islands: A Cluster Randomized Survey

    PubMed Central

    Marks, Michael; Vahi, Ventis; Sokana, Oliver; Puiahi, Elliot; Pavluck, Alex; Zhang, Zaixing; Dalipanda, Tenneth; Bottomley, Christian; Mabey, David C.; Solomon, Anthony W.

    2015-01-01

    Yaws, a non-venereal treponemal disease, is targeted for eradication by 2020 but accurate epidemiological data to guide control programs remain sparse. The Solomon Islands reports the second highest number of cases of yaws worldwide. We conducted a cluster randomized survey of yaws in two provinces of the Solomon Islands. One thousand four hundred and ninety-seven (1,497) children 5–14 years of age were examined. Clinical signs of active yaws were found in 79 children (5.5%), whereas 140 children (9.4%) had evidence of healed yaws lesions. Four hundred and seventy (470) (31.4%) children had a positive Treponema pallidum particle agglutination assay (TPPA). Two hundred and eighty-five (285) children (19%) had a positive TPPA and rapid plasma regain assay. Risk of yaws increased with age and was more common in males. The prevalence of yaws at village level was the major risk factor for infection. Our findings suggest the village, not the household, should be the unit of treatment in the World Health Organization (WHO) yaws eradication strategy. PMID:25422395

  20. Tuberculosis notifications, characteristics and treatment outcomes: urban vs. rural Solomon Islands, 2000–2011

    PubMed Central

    Hill, P. C.; Bissell, K.; Harries, A. D.; Viney, K.; Gounder, S.

    2014-01-01

    Setting: All provincial tuberculosis (TB) management units in the Solomon Islands. Objective: To compare TB notifications, characteristics and treatment outcomes in urban vs. rural areas. Design: A retrospective descriptive cohort study involving record review and data extraction from provincial TB and laboratory registers and treatment charts from 2000 to 2011. Results: Of 4137 TB cases notified, 1364 (33%) were from urban and 3227 (67%) from rural areas. Notification rates per year of study were consistently higher in urban areas (104–150 per 100 000 population) than in rural areas (49–70/100 000). Cases in rural areas were more likely to have smear-negative pulmonary TB and less likely to have extra-pulmonary TB (P < 0.001). TB cases in rural areas were more likely to die from TB than those from urban areas (3.2% vs. 5.9%). In contrast, TB cases in rural areas were less likely to default (2.8% vs. 1.8%). Conclusion: TB notification rates were much higher in urban than in rural areas in the Solomon Islands. Rural patients are more likely to die from the disease but are slightly less likely to default. Further research is required to explore the possibility of under-reporting in rural areas and to improve treatment outcomes. PMID:26477283

  1. Mapping the epidemiology of yaws in the Solomon Islands: a cluster randomized survey.

    PubMed

    Marks, Michael; Vahi, Ventis; Sokana, Oliver; Puiahi, Elliot; Pavluck, Alex; Zhang, Zaixing; Dalipanda, Tenneth; Bottomley, Christian; Mabey, David C; Solomon, Anthony W

    2015-01-01

    Yaws, a non-venereal treponemal disease, is targeted for eradication by 2020 but accurate epidemiological data to guide control programs remain sparse. The Solomon Islands reports the second highest number of cases of yaws worldwide. We conducted a cluster randomized survey of yaws in two provinces of the Solomon Islands. One thousand four hundred and ninety-seven (1,497) children 5-14 years of age were examined. Clinical signs of active yaws were found in 79 children (5.5%), whereas 140 children (9.4%) had evidence of healed yaws lesions. Four hundred and seventy (470) (31.4%) children had a positive Treponema pallidum particle agglutination assay (TPPA). Two hundred and eighty-five (285) children (19%) had a positive TPPA and rapid plasma regain assay. Risk of yaws increased with age and was more common in males. The prevalence of yaws at village level was the major risk factor for infection. Our findings suggest the village, not the household, should be the unit of treatment in the World Health Organization (WHO) yaws eradication strategy. PMID:25422395

  2. Vector-control response in a post-flood disaster setting, Honiara, Solomon Islands, 2014

    PubMed Central

    Musto, Jennie; Bugoro, Hugo; Butafa, Charles; Sio, Alison; Joshua, Cynthia

    2016-01-01

    Problem The close quartering and exposed living conditions in evacuation centres and the potential increase in vector density after flooding in Solomon Islands resulted in an increased risk of exposure for the occupants to vectorborne diseases. Context In April 2014, Solomon Islands experienced a flash flooding event that affected many areas and displaced a large number of people. In the capital, Honiara, nearly 10 000 people were housed in emergency evacuation centres at the peak of the post-flood emergency. At the time of the floods, the number of dengue cases was increasing, following a record outbreak in 2013. Action The National Vector Borne Disease Control Programme with the assistance of the World Health Organization implemented an emergency vector-control response plan to provide protection to the at-risk populations in the evacuation centres. The National Surveillance Unit also activated an early warning disease surveillance system to monitor communicable diseases, including dengue and malaria. Outcome Timely and strategic application of the emergency interventions probably prevented an increase in dengue and malaria cases in the affected areas. Discussion Rapid and appropriate precautionary vector-control measures applied in a post-natural disaster setting can prevent and mitigate vectorborne disease incidences. Collecting vector surveillance data allows better analysis of vector-control operations’ effectiveness. PMID:27757255

  3. Spatial Distribution and Sedimentary Facies of the 2007 Solomon Islands Tsunami Deposits

    NASA Astrophysics Data System (ADS)

    Nakamura, Y.; Nishimura, Y.; Woodward, S.

    2007-12-01

    We conducted a field survey of the extent of damage, crustal deformation, and onshore deposits caused by 2007 Solomon Islands tsunami in Ghizo and adjacent islands in the western Solomon Islands, from 13th to 18th April, 2007. Our survey team was comprised of six Japanese and one American researcher. Three of us, the authors, mainly investigated tsunami deposits in three villages (Titiana, Suva, and Pailongge) in southern Ghizo Island. One member of our team re-investigated the deposits in June 2007. The tsunami generated sheet-like deposits of coral beach sand on the flat plain in Titiana. Beside the sea coast, the tsunami wave eroded ground surfaces and formed small scarps at 30 m from the sea. Just interior of the scarps, tsunami deposits accumulated up to 9 cm in thickness. The thickness decreased with distance from the sea and was also affected by microtopography. No sandy tsunami deposits were observed on the inland area between 170 m and 210 m from the sea. The upper boundary of inundation was recognized at about 210 m from the sea because of accumulation of driftwood and floating debris. In Suva and Pailongge, the outline of sand-sheet distribution is the same as it in Titiana. The tsunami had a maximum thickness of 10 cm and two or three sand layers are separated by thin humic sand layers. These humic layers were likely supplied from hillslopes eroded by the tsunami and transported by return-flows. These successions of deposits suggest that tsunami waves inundated at least two times. This is consistent with the number of large waves told by eyewitnesses. In the Solomon Islands, the plentiful rainfall causes erosion and resedimentation of tsunami deposits. Furthermore, the sedimentary structures will be destroyed by chemical weathering in warm and moist environment, and bioturbation by plants, animals, and human activities. The sedimentary structures had been preserved till the end of June 2007, but had already been penetrated by plant roots and sandpipes

  4. Seismogenic Fault Geometry of 2010 Mw 7.1 Solomon Islands Earthquake

    NASA Astrophysics Data System (ADS)

    Kuo, Y.; Ku, C.; Taylor, F. W.; Huang, B.; Chen, Y.; Chao, W.; Huang, H.; Kuo, Y.; Wu, Y.; Suppe, J.

    2010-12-01

    The Solomon Islands is located in southwestern Pacific, where the Indo-Australian Plate is subducting northeastward beneath the Pacific Plate. Due to subduction of rugged seafloor topography, including seamounts, the seismic activity and tectonic behavior may be complicated. Seismicity in this region was anomalously low until 2007 when a megathrust rupture (Mw 8.1) occurred. More recently, on 3 January 2010, a Mw7.1 earthquake occurred beneath the extreme outer forearc next to the trench. It came with one foreshock (Mw 6.6, 50 minutes ahead) and two large aftershocks (Mw 6.8 and 6.0) greater than magnitude 6 within a week. It is interesting to note that these four focal mechanisms are very much similar and appear to have occurred along the interplate thrust zone between the Indo-Australian plate and Solomon Islands forearc. This Earthquake nucleated approximately 50 km to the southeast of the M8.1 Earthquake occurring in April of 2007, which is located to the other side of Rendova Island. Because a tsunami followed the 2010 earthquake, it is likely that submarine surface deformation accompanied the event. By the results of D-InSAR on ALOS and ERS, plus limited points of ground displacement from GPS and strong motion seismometers, the continuous ground displacement field is constructed and normalized. Our preliminary result shows the ground movement in the Rendova Island can reach tens of centimeters, implying shallow earthquake source consistent with the suggestion by triggering tsunami. Besides, the earthquake sequence retrieved from our local seismometer observation network allows us to further define underground fault geometry. The spatial distribution of the epicenter also concludes the seamount located in the middle divides two seismogenic asperities which generate 2007 and 2010 earthquakes respectively.

  5. The Prevalence of Scabies and Impetigo in the Solomon Islands: A Population-Based Survey

    PubMed Central

    Marks, Michael; Sokana, Oliver; Solomon, Anthony W.; Mabey, David C.; Romani, Lucia; Kaldor, John; Steer, Andrew C.; Engelman, Daniel

    2016-01-01

    Background Scabies and impetigo are common, important and treatable skin conditions. Reports from several Pacific island countries show extremely high prevalence of these two conditions, but for many countries, including the Solomon Islands, there is a paucity of epidemiological data. Methodology Ten rural villages in the Western Province of the Solomon Islands were included in the study, chosen so that data collection could be integrated with an existing project investigating clinical and serological markers of yaws. All residents were eligible to participate, and 1908 people were enrolled. Participants were interviewed and examined by a paediatric registrar, who recorded relevant demographic information, and made a clinical diagnosis of scabies and/or impetigo, severity and distribution. Principal Findings The total unweighted prevalence of scabies was 19.2% (95% confidence interval [CI] 17.5–21.0), and age and gender weighted prevalence 19.2% (95%CI 16.7–21.9). The adult prevalence of scabies was 10.4% (95%CI 8.2–13.2), and the highest prevalence was found in infants < 1 year of age (34.1%, adjusted odds ratio [AOR] compared with adults: 3.6, 95%CI 2.2–6.0) and children aged 1–4 years (25.7%, AOR 2.6, 95%CI 1.7–3.9). Scabies affected two or more body regions in 80.9% of participants, and 4.4% of scabies cases were classified as severe. The total unweighted prevalence of active impetigo was 32.7% (95%CI 30.6–34.8), and age and gender weighted prevalence 26.7% (95%CI 24.2–29.5). The highest prevalence was found in children aged 1–4 years (42.6%, AOR compared with adults: 4.1, 95%CI 2.9–5.8). Scabies infestation was associated with active impetigo infection (AOR 2.0, 95%CI 1.6–2.6); with 41.1% of active impetigo cases also having scabies. Conclusions and Significance Scabies and impetigo are very common in the rural Western Province of the Solomon Islands. Scabies infestation is strongly associated with impetigo. Community control strategies

  6. An Examination of Seismicity Linking the Solomon Islands and Vanuatu Subduction Zones

    NASA Astrophysics Data System (ADS)

    Neely, J. S.; Furlong, K. P.

    2015-12-01

    The Solomon Islands-Vanuatu composite subduction zone represents a tectonically complex region along the Pacific-Australia plate boundary in the southwest Pacific Ocean. Here the Australia plate subducts under the Pacific plate in two segments: the South Solomon Trench and the Vanuatu Trench. The two subducting sections are offset by a 200 km long, transform fault - the San Cristobal Trough (SCT) - which acts as a Subduction-Transform Edge Propagator (STEP) fault. The subducting segments have experienced much more frequent and larger seismic events than the STEP fault. The northern Vanuatu trench hosted a M8.0 earthquake in 2013. In 2014, at the juncture of the western terminus of the SCT and the southern South Solomon Trench, two earthquakes (M7.4 and M7.6) occurred with disparate mechanisms (dominantly thrust and strike-slip respectively), which we interpret to indicate the tearing of the Australia plate as its northern section subducts and southern section translates along the SCT. During the 2013-2014 timeframe, little seismic activity occurred along the STEP fault. However, in May 2015, three M6.8-6.9 strike-slip events occurred in rapid succession as the STEP fault ruptured east to west. These recent events share similarities with a 1993 strike-slip STEP sequence on the SCT. Analysis of the 1993 and 2015 STEP earthquake sequences provides constraints on the plate boundary geometry of this major transform fault. Preliminary research suggests that plate motion along the STEP fault is partitioned between larger east-west oriented strike-slip events and smaller north-south thrust earthquakes. Additionally, the differences in seismic activity between the subducting slabs and the STEP fault can provide insights into how stress is transferred along the plate boundary and the mechanisms by which that stress is released.

  7. Crustal deformation in the Western Solomon Islands revealed by GPS observation during 2009 - 2012

    NASA Astrophysics Data System (ADS)

    Kuo, Y.; Lin, K.; Ku, C.; Taylor, F. W.; Chen, Y.; Huang, B.

    2012-12-01

    The plate boundary along the southern margin of the Solomon Islands, southwestern Pacific, is characterized by convergent tectonic processes between the Indo-Australian Plate and Pacific Plate. The horizontal convergence rate between two plates is 135 mm/yr in the direction of N45°E. In terms of the structure, this subduction zone is relatively complicated because large seamounts are involved in subduction of extremely young lithosphere generated by the Woodlark spreading system. Hence, the crustal deformation is essential to reconstructing the structural model that constitutes and operates the entire subduction system. For the purpose of monitoring crustal motion, we began to deploy continuous mode GPS stations in September 2009. All of them have been working for 1-3 yr. The total horizontal rates are 95±1, 52±3, 78±7, 120±14, 114±7, and 114±7 mm/yr for Sibo, Nusu, Lale, Husu, Tepa, and Sege respectively. However, the moving directions are N23°E, N63°W, N10°W, N65°W, N63°W, and N69°W. During 2009, the uplift rates are -31±8 and 50±17 mm/yr for Sibo and Nusu, but during 2010, the rate are 2±2 and 13±9 mm/yr. The larger slips may cause of the postseismic deformation of 2007 Mw8.1 Solomon Earthquake. It also shows the large uplift rates on Husu (98±36 mm/yr), Tepa (60±11 mm/yr) and Sege (33±10 mm/yr) after the 2010 Mw7.1 Solomon Earthquake; however, it still needs longer measuring time to confirm the tectonic behavior.

  8. Geologic Survey of the 2 April 2007 Solomon Islands Earthquake and Tsunami

    NASA Astrophysics Data System (ADS)

    Rafiau, W. B.; Jackson, K. L.; Billy, D.; Bonte-Grapentin, M.; Kruger, J.; McAdoo, B. G.; Moore, A. L.; Tiano, B.

    2007-12-01

    The 2 April 2007 magnitude 8.1 Solomon Islands earthquake and tsunami caused extensive damage to coral reefs, coastal erosion, and in some locations, 3 meters of uplift, subsidence, and numerous landslides in the Western and Choiseul Provinces. Extensive damage to the coral reefs ranged from shattered branching corals to 4 meter head corals snapped off their bases and toppled over. The fringing reef on the east coast of Ranongga sustained the greatest degree of damage as it was uplifted 3 m above sea level and remains completely exposed. Sediment samples were collected along transects extended from offshore to onshore environments for larger islands, such as Ghizo, where the tsunami did not pass over the entire island. Smaller islands, such as Nusa Aghana, a transect was conducted from the outer barrier reefs, through the lagoon, across the island, and offshore on the opposing side of the island. Offshore data was collected using a side-scan sonar system that records bathymetry and images coral reef morphology. This data was coupled with snorkeling and SCUBA diving to ground truth the offshore lagoon and reef environments. Sediment samples were collected offshore every 5 m and were documented by underwater photos and GPS coordinates. Offshore to onshore sediment transects reveal that sediment was eroded from seaward facing shorelines, deposited a thin veneer of sediment on islands, and transported the majority of the sediment on coral reefs on the lagoon side of islands, essentially burying coral and lagoonal sediment. Coral reef damaged by the earthquake and tsunami represents a major concern for an already threatened ecosystem. Recovery of the fishing and dive tourism economies rely on the healthy reestablishment of the reef.

  9. Thick Explanation in the Ethnographic Study of Child Socialization: A Longitudinal Study of the Problem of Schooling for Kwara'ae (Solomon Islands) Children.

    ERIC Educational Resources Information Center

    Watson-Gegeo, Karen Ann

    1992-01-01

    Outlines a framework for examining children's socialization that combines microlevels and macrolevels. Applies the framework to a case study of student failure in the Solomon Islands. Concludes that children's failure had less to do with home socialization than with larger societal processes that shape schooling in the Solomons. (MM)

  10. Bionomics of the malaria vector Anopheles farauti in Temotu Province, Solomon Islands: issues for malaria elimination

    PubMed Central

    2011-01-01

    Background In the Solomon Islands, the Malaria Eradication Programmes of the 1970s virtually eliminated the malaria vectors: Anopheles punctulatus and Anopheles koliensis, both late night biting, endophagic species. However, the vector, Anopheles farauti, changed its behaviour to bite early in the evening outdoors. Thus, An. farauti mosquitoes were able to avoid insecticide exposure and still maintain transmission. Thirty years on and the Solomon Islands are planning for intensified malaria control and localized elimination; but little is currently known about the behaviour of the vectors and how they will respond to intensified control. Methods In the elimination area, Temotu Province, standard entomological collection methods were conducted in typical coastal villages to determine the vector, its ecology, biting density, behaviour, longevity, and vector efficacy. These vector surveys were conducted pre-intervention and post-intervention following indoor residual spraying and distribution of long-lasting insecticidal nets. Results Anopheles farauti was the only anopheline in Temotu Province. In 2008 (pre-intervention), this species occurred in moderate to high densities (19.5-78.5 bites/person/night) and expressed a tendency to bite outdoors, early in the night (peak biting time 6-8 pm). Surveys post intervention showed that there was little, if any, reduction in biting densities and no reduction in the longevity of the vector population. After adjusting for human behaviour, indoor biting was reduced from 57% pre-intervention to 40% post-intervention. Conclusion In an effort to learn from historical mistakes and develop successful elimination programmes, there is a need for implementing complimentary vector control tools that can target exophagic and early biting vectors. Intensified indoor residual spraying and long-lasting insecticide net use has further promoted the early, outdoor feeding behaviour of An. farauti in the Solomon Islands. Consequently, the

  11. 2007 Solomon Islands Tsunami Left Little Sand Onshore, Buried Backshore Reefs

    NASA Astrophysics Data System (ADS)

    Moore, A. L.; Jackson, K. L.; Kruger, J.; McAdoo, B. G.; Rafiau, W. B.; Tiano, B.; Woodward, S. M.

    2007-12-01

    In many places struck by the 2007 Solomon Islands tsunami, little onshore record of the tsunami's passage remains yet considerable sediment was transported offshore. This sediment represents an ecological hazard in tropical regions because of its potential for burying coral reefs. At Nusa Agana, a 50 m-wide, 2 m-high barrier island ~36 km N of the epicenter, flow depths recorded by debris wrapped around tree trunks did not exceed 50 cm--the sedimentary record on land was similarly small at ~2 cm thick. Nevertheless, the "outer" coastline of the island was stripped of sediment and the "inner" coastline filled with enough sediment to bury coral reefs to an extent that only soft corals at the top of the reef survive. The source of the sediment appears to be a mixture of sand from both the outer and inner beach, suggesting that scour occurred at both these locations. Perhaps because of the island's low relief, Nusa Agana acted less as a barrier to flow and more as a topographic high; sediment cover thinned over the high and selectively infilled the topographic low of the lagoon. At Tapurai, ~55 km ENE of the epicenter, the tsunami left a layer of coral rubble 20-30 cm thick and moved basalt boulders up to 1 m in diameter more than 100 m inland. The tsunami here reached flow depths of more than 8 m and swept N-SW across fan-shaped Tapurai, piling coral rubble mixed from offshore reefs and the modern beach onto farm fields before striking a basalt cliff behind the town and deflecting SW, carrying basalt debris with it before exiting through the town's harbor. The sediment leaves a vivid account of the passage of the wave, progressing from a solely coral rubble deposit to a mixed basalt-coral deposit and thinning downflow as sediment supply waned. Where the tsunami washed completely over islands, the side facing the waves is typically stripped of sediment, whereas the lee side shows a well developed scarp, suggesting that at least some tsunami scarps are formed during

  12. The Solomon Islands Tsunami of 6 February 2013 in the Santa Cruz Islands: Field Survey and Modeling

    NASA Astrophysics Data System (ADS)

    Fritz, Hermann M.; Papantoniou, Antonios; Biukoto, Litea; Albert, Gilly; Wei, Yong

    2014-05-01

    On February 6, 2013 at 01:12:27 UTC (local time: UTC+11), a magnitude Mw 8.0 earthquake occurred 70 km to the west of Ndendo Island (Santa Cruz Island) in the Solomon Islands. The under-thrusting earthquake near a 90° bend, where the Australian plate subducts beneath the Pacific plate generated a locally focused tsunami in the Coral Sea and the South Pacific Ocean. The tsunami claimed the lives of 10 people and injured 15, destroyed 588 houses and partially damaged 478 houses, affecting 4,509 people in 1,066 households corresponding to an estimated 37% of the population of Santa Cruz Island. A multi-disciplinary international tsunami survey team (ITST) was deployed within days of the event to document flow depths, runup heights, inundation distances, sediment and coral boulder depositions, land level changes, damage patterns at various scales, performance of the man-made infrastructure and impact on the natural environment. The 19 to 23 February 2013 ITST covered 30 locations on 4 Islands: Ndendo (Santa Cruz), Tomotu Noi (Lord Howe), Nea Tomotu (Trevanion, Malo) and Tinakula. The reconnaissance completely circling Ndendo and Tinakula logged 240 km by small boat and additionally covered 20 km of Ndendo's hard hit western coastline by vehicle. The collected survey data includes more than 80 tsunami runup and flow depth measurements. The tsunami impact peaked at Manoputi on Ndendo's densely populated west coast with maximum tsunami height exceeding 11 m and local flow depths above ground exceeding 7 m. A fast tide-like positive amplitude of 1 m was recorded at Lata wharf inside Graciosa Bay on Ndendo Island and misleadingly reported in the media as representative tsunami height. The stark contrast between the field observations on exposed coastlines and the Lata tide gauge recording highlights the importance of rapid tsunami reconnaissance surveys. Inundation distance and damage more than 500 m inland were recorded at Lata airport on Ndendo Island. Landslides were

  13. The Solomon Islands Tsunami of 6 February 2013 in the Santa Cruz Islands: Field Survey and Modeling

    NASA Astrophysics Data System (ADS)

    Fritz, Hermann M.; Papantoniou, Antonios; Biukoto, Litea; Albert, Gilly; Wei, Yong

    2014-05-01

    On February 6, 2013 at 01:12:27 UTC (local time: UTC+11), a magnitude Mw 8.0 earthquake occurred 70 km to the west of Ndendo Island (Santa Cruz Island) in the Solomon Islands. The under-thrusting earthquake near a 90° bend, where the Australian plate subducts beneath the Pacific plate generated a locally focused tsunami in the Coral Sea and the South Pacific Ocean. The tsunami claimed the lives of 10 people and injured 15, destroyed 588 houses and partially damaged 478 houses, affecting 4,509 people in 1,066 households corresponding to an estimated 37% of the population of Santa Cruz Island. A multi-disciplinary international tsunami survey team (ITST) was deployed within days of the event to document flow depths, runup heights, inundation distances, sediment and coral boulder depositions, land level changes, damage patterns at various scales, performance of the man-made infrastructure and impact on the natural environment. The 19 to 23 February 2013 ITST covered 30 locations on 4 Islands: Ndendo (Santa Cruz), Tomotu Noi (Lord Howe), Nea Tomotu (Trevanion, Malo) and Tinakula. The reconnaissance completely circling Ndendo and Tinakula logged 240 km by small boat and additionally covered 20 km of Ndendo's hard hit western coastline by vehicle. The collected survey data includes more than 80 tsunami runup and flow depth measurements. The tsunami impact peaked at Manoputi on Ndendo's densely populated west coast with maximum tsunami height exceeding 11 m and local flow depths above ground exceeding 7 m. A fast tide-like positive amplitude of 1 m was recorded at Lata wharf inside Graciosa Bay on Ndendo Island and misleadingly reported in the media as representative tsunami height. The stark contrast between the field observations on exposed coastlines and the Lata tide gauge recording highlights the importance of rapid tsunami reconnaissance surveys. Inundation distance and damage more than 500 m inland were recorded at Lata airport on Ndendo Island. Landslides were

  14. Coseismic and Postseismic slip distribution of the 2007 Solomon Islands Earthquake deduced from A Bayesian Inversion

    NASA Astrophysics Data System (ADS)

    Chen, T.; Gong, X.

    2011-12-01

    In inversion of geodetic data for distribution of fault slip minimizing the first or second order derivatives of slip across fault plane is generally employed to smooth slips of neighboring patches.Smoothing parameter is subjective selected to determine the relative weight placed on fitting data versus smoothing the slip distribution.We use the Fully Bayesian Inversion method(Fukuda,2008)to simultaneously estimate the slip distribution and smoothing parameter objectively in a Bayesian framework. The distributed slips,the posterior probability density function and the smoothing parameter is formulated with Bayes' theorem and sampled with a Markov chain Monte Carlo method. Here We will apply this method to Coseismic and Postseismic displacement data from the 2007 Solomon Islands Earthquake and compare the results of this method with generally favored method.

  15. A review of health leadership and management capacity in the Solomon Islands.

    PubMed

    Asante, Augustine; Roberts, Graham; Hall, John

    2012-04-01

    ACCESS AND UTILISATION OF HEALTH CARE: The armed conflict that engulfed the Solomon Islands between 1998 and 2003 significantly disrupted the provision of health care especially in rural and remote areas. There is one doctor for 3,300 people and approximately 13 nurses and midwives for 10,000 people. Despite limitations 87% of people seek health care when sick. FINANCING THE HEALTH SYSTEM: The SIG placed a series of reservations on ministerial goods and services budgets that effectively the budget by 33%, severely impacting provincial budgets and resulting in acquired debts. Shortfalls have been addressed by allocating Health Sector Support Program funds to the provinces to allow services to continue, a strategy that will likely recur, but by which donor support replaces government provision Provincial health accountants have received training in MYOB in 2009 but acquittal systems require higher level accounting skills for reports to be submitted on time to permit the release of subsequent funding tranches. HUMAN RESOURCES FOR HEALTH: The shortage of doctors and specialists is a key challenge. As at December 2010, there were a total of 2,728 health workers in the public sector in Solomon Islands. Staff costs consume on average 55% of provincial health grants Filled Public Service Division staff establishments and budgetary reservations have reduced the ability to meet the salary and wage costs of new graduates. Solomon Islands is currently negotiating to assist Vanuatu in filling its nursing staff vacancies with its surplus The return of 75 Cuban trained medical officers from 2013 presents the management challenge of accessing budget provisions for so many new positions and in funding the infrastructure needed to house, equip and maintain them in service. HEALTH MANAGEMENT STRUCTURE: Provincial health managers are operationally responsive to local needs, managerially responsible to provincial governments, while being concerned with adherence to central MHMS policy

  16. Marine protected areas and resilience to sedimentation in the Solomon Islands

    NASA Astrophysics Data System (ADS)

    Halpern, B. S.; Selkoe, K. A.; White, C.; Albert, S.; Aswani, S.; Lauer, M.

    2013-03-01

    The ability of marine protected areas (MPAs) to provide protection from indirect stressors, via increased resilience afforded by decreased impact from direct stressors, remains an important and unresolved question about the role MPAs can play in broader conservation and resource management goals. Over a five-year period, we evaluated coral and fish community responses inside and outside three MPAs within the Roviana Lagoon system in Solomon Islands, where sedimentation pressure from upland logging is substantial. We found little evidence that MPAs decrease impact or improve conditions and instead found some potential declines in fish abundance. We also documented modest to high levels of poaching during this period. Where compliance with management is poor, and indirect stressors play a dominant role in determining ecosystem condition, as appears to be the case in Roviana Lagoon, MPAs may provide little management benefit.

  17. Sexual development and reproductive demography of the green humphead parrotfish ( Bolbometopon muricatum) in the Solomon Islands

    NASA Astrophysics Data System (ADS)

    Hamilton, R. J.; Adams, S.; Choat, J. H.

    2008-03-01

    An investigation of the reproductive biology of the green humphead parrotfish ( Bolbometopon muricatum) from three areas in the Western Province of the Solomon Islands revealed that B. muricatum exhibits several features that differ from the pattern of reproductive development observed in most parrotfishes. Unlike most parrotfishes, histological evidence suggests that the sexual pattern of B. muricatum is essentially gonochoristic with high incidences of anatomical but non-functional hermaphroditism. B. muricatum also differs from other parrotfishes in that all males pass through an immature female (or bisexual) phase as demonstrated by all adult testis retaining the ex-ovarian lumen and peripheral sperm sinuses in the gonad wall. However, a protogynous diandric reproductive strategy cannot be excluded given that sampling may have missed transitional individuals. Marked variation in the demography of male B. muricatum between the three locations examined is considered to reflect variation in historical fishing effort.

  18. A review of health leadership and management capacity in the Solomon Islands.

    PubMed

    Asante, Augustine; Roberts, Graham; Hall, John

    2012-04-01

    ACCESS AND UTILISATION OF HEALTH CARE: The armed conflict that engulfed the Solomon Islands between 1998 and 2003 significantly disrupted the provision of health care especially in rural and remote areas. There is one doctor for 3,300 people and approximately 13 nurses and midwives for 10,000 people. Despite limitations 87% of people seek health care when sick. FINANCING THE HEALTH SYSTEM: The SIG placed a series of reservations on ministerial goods and services budgets that effectively the budget by 33%, severely impacting provincial budgets and resulting in acquired debts. Shortfalls have been addressed by allocating Health Sector Support Program funds to the provinces to allow services to continue, a strategy that will likely recur, but by which donor support replaces government provision Provincial health accountants have received training in MYOB in 2009 but acquittal systems require higher level accounting skills for reports to be submitted on time to permit the release of subsequent funding tranches. HUMAN RESOURCES FOR HEALTH: The shortage of doctors and specialists is a key challenge. As at December 2010, there were a total of 2,728 health workers in the public sector in Solomon Islands. Staff costs consume on average 55% of provincial health grants Filled Public Service Division staff establishments and budgetary reservations have reduced the ability to meet the salary and wage costs of new graduates. Solomon Islands is currently negotiating to assist Vanuatu in filling its nursing staff vacancies with its surplus The return of 75 Cuban trained medical officers from 2013 presents the management challenge of accessing budget provisions for so many new positions and in funding the infrastructure needed to house, equip and maintain them in service. HEALTH MANAGEMENT STRUCTURE: Provincial health managers are operationally responsive to local needs, managerially responsible to provincial governments, while being concerned with adherence to central MHMS policy

  19. Preliminary volcano-hazard assessment for Akutan Volcano east-central Aleutian Islands, Alaska

    USGS Publications Warehouse

    Waythomas, Christopher F.; Power, John A.; Richter, Donlad H.; McGimsey, Robert G.

    1998-01-01

    Akutan Volcano is a 1100-meter-high stratovolcano on Akutan Island in the east-central Aleutian Islands of southwestern Alaska. The volcano is located about 1238 kilometers southwest of Anchorage and about 56 kilometers east of Dutch Harbor/Unalaska. Eruptive activity has occurred at least 27 times since historical observations were recorded beginning in the late 1700?s. Recent eruptions produced only small amounts of fine volcanic ash that fell primarily on the upper flanks of the volcano. Small amounts of ash fell on the Akutan Harbor area during eruptions in 1911, 1948, 1987, and 1989. Plumes of volcanic ash are the primary hazard associated with eruptions of Akutan Volcano and are a major hazard to all aircraft using the airfield at Dutch Harbor or approaching Akutan Island. Eruptions similar to historical Akutan eruptions should be anticipated in the future. Although unlikely, eruptions larger than those of historical time could generate significant amounts of volcanic ash, fallout, pyroclastic flows, and lahars that would be hazardous to life and property on all sectors of the volcano and other parts of the island, but especially in the major valleys that head on the volcano flanks. During a large eruption an ash cloud could be produced that may be hazardous to aircraft using the airfield at Cold Bay and the airspace downwind from the volcano. In the event of a large eruption, volcanic ash fallout could be relatively thick over parts of Akutan Island and volcanic bombs could strike areas more than 10 kilometers from the volcano.

  20. Critical care resources in the Solomon Islands: a cross-sectional survey

    PubMed Central

    2012-01-01

    Background There are minimal data available on critical care case-mix, care processes and outcomes in lower and middle income countries (LMICs). The objectives of this paper were to gather data in the Solomon Islands in order to gain a better understanding of common presentations of critical illness, available hospital resources, and what resources would be helpful in improving the care of these patients in the future. Methods This study used a mixed methods approach, including a cross sectional survey of respondents' opinions regarding critical care needs, ethnographic information and qualitative data. Results The four most common conditions leading to critical illness in the Solomon Islands are malaria, diseases of the respiratory system including pneumonia and influenza, diabetes mellitus and tuberculosis. Complications of surgery and trauma less frequently result in critical illness. Respondents emphasised the need for basic critical care resources in LMICs, including equipment such as oximeters and oxygen concentrators; greater access to medications and blood products; laboratory services; staff education; and the need for at least one national critical care facility. Conclusions A large degree of critical illness in LMICs is likely due to inadequate resources for primary prevention and healthcare; however, for patients who fall through the net of prevention, there may be simple therapies and context-appropriate resources to mitigate the high burden of morbidity and mortality. Emphasis should be on the development and acquisition of simple and inexpensive tools rather than complicated equipment, to prevent critical care from unduly diverting resources away from other important parts of the health system. PMID:22376229

  1. Melt Inclusion Evidence for Subduction-modified Mantle Beneath the Woodlark Spreading Center, Solomon Islands

    NASA Astrophysics Data System (ADS)

    Chadwick, J.; Turner, A.; Collins, E.

    2015-12-01

    The Woodlark Spreading Center (WSC) to the east of Papua New Guinea separates the Indo-Australian plate and Solomon Sea microplate. At its eastern terminus, the WSC is being subducted at the New Britain trench, forming a triple junction near the New Georgia Group arc in the Solomon Islands. Previous studies have shown that lavas recovered from greater than 100 km from the trench on the WSC are N-MORB, but closer to the trench they have arc-like Sr-Nd-Pb isotopic ratios, enrichments in LILE, and depletions in HFSE. In the complex triple junction area of the WSC on the Simbo and Ghizo Ridges, island arc tholeiites to medium-K calc-alkaline andesites and dacites have been recovered, many with trace element and isotopic characteristics that are similar to the true arc lavas in the New Georgia Group on the other side of the trench. We suggest that subduction-modified arc mantle migrates through slab windows created by the subduction of the WSC as the plates continue to diverge after subduction. This transfer of mantle across the plate boundary leads to variable mixing between arc and N-MORB end-members, forming the hybrid to arc-like lavas recovered on the WSC. To test this hypothesis and to characterize the end-member compositions, we have analyzed melt inclusions in olivine, pyroxene, and plagioclase phenocrysts in Simbo and Ghizo Ridge lava samples. Major elements were analyzed using the electron microprobe facility at Fayetteville State University and volatiles were analyzed on the ion probe facility at Woods Hole Oceanographic Institution. The melt inclusions show a wide diversity of magmas from basalts to dacites, and mixing modeling shows that most Woodlark Spreading Center lava compositions are explained by mixing between the most extreme mafic (MORB) and felsic (arc) inclusion compositions.

  2. Research workshop to research work: initial steps in establishing health research systems on Malaita, Solomon Islands

    PubMed Central

    2010-01-01

    Introduction Atoifi Adventist Hospital is a 90 bed general hospital in East Kwaio, Malaita, Solomon Islands providing services to the population of subsistence villagers of the region. Health professionals at the hospital and attached College of Nursing have considerable human capacity and willingness to undertake health research. However they are constrained by limited research experience, training opportunities, research systems, physical infrastructure and access to resources. This brief commentary describes an 'Introduction to Health Research' workshop delivered at Atoifi Adventist Hospital in September 2009 and efforts to move from 'research workshop' to 'research work'. The Approach Using a participatory-action research approach underpinned by decolonising methodologies, staff from Atoifi Adventist Hospital and James Cook University (Queensland, Australia) collaboratively designed, implemented and evaluated a health research workshop. Basic health research principles and methods were presented using active learning methodologies. Following the workshop, Atoifi Adventist Hospital and Atoifi College of Nursing staff, other professionals and community members reported an increased awareness and understanding of health research. The formation of a local Research Committee, improved ethics review procedures and the identification of local research mentors followed the week long workshop. The workshop has acted as a catalyst for research activity, increasing structural and human resource capacity for local health professionals and community leaders to engage in research. Discussion and Conclusions Participants from a variety of educational backgrounds participated in, and received benefit from, a responsive, culturally and linguistically accessible health research workshop. Improving health research systems at a remote hospital and aligning these with local and national research agendas is establishing a base to strengthen public health research and practice on

  3. Prevalence of antibodies interactive with HTLV-I antigens in selected Solomon Islands populations.

    PubMed

    Armstrong, M Y; Hrdy, D B; Carlson, J R; Friedlaender, J S

    1990-04-01

    Serum samples obtained in 1986 from healthy individuals in three distinct Solomon Islands populations were screened for antibodies to human lymphotropic virus type I (HTLV-I). One of the populations tested lives on the remote Polynesian outlier atoll, Ontong Java. The other two groups, the Baegu and the Lau, are Melanesians living on Malaita, the most populous of the larger Solomon Islands. Eighty-eight of a total of 601 (14.6%) sera tested were repeatably reactive in an enzyme-linked immunosorbent assay (ELISA) that uses as antigen a lysate of HTLV-I viral particles. The prevalence of antibodies interactive with HTLV-I viral particles. The prevalence of antibodies interactive with HTLV-I antigens varied among the three groups, ranging from 8.5% (16/188) in the Baegu, through 13% (7/54) in the Lau, to 18.1% (65/359) among the Ontong Java population. The specificity of the screening ELISA was confirmed by protein immunoblot. No serum samples were obtained from children under 9 years of age. Although 121 of the 601 sera came from children between the ages of 9 and 19, none of these were reactive in the HTLV-I ELISA. Starting in the third decade, the prevalence of HTLV-I seropositivity increased with age, from 8.8% (10/113) between the ages of 20 and 29 to a peak of 25.9% (15/58) and 25% (15/60) in the sixth and seventh decade, respectively. This age-specific prevalence pattern is strikingly similar to that which is seen in populations where HTLV-I infection is endemic. PMID:2333936

  4. Hospital visits due to domestic violence from 1994 to 2011 in the Solomon Islands: a descriptive case series.

    PubMed

    Farrell, Penny C; Negin, Joel; Houasia, Patrick; Munamua, Alex B; Leon, David P; Rimon, Mia; Martiniuk, Alexandra L C

    2014-09-01

    The Solomon Islands has one of the highest rates of domestic violence in the world. This paper is a descriptive case series of all cases of domestic violence presenting to the Solomon Islands National Referral Hospital (NRH) over 18 years. Data were routinely collected from a database of all patients who were treated by NRH general surgery and orthopedic clinicians between 1994 and 2011, inclusive. The total number of cases in the injury database as a result of domestic violence was 387. The average number of cases in the database per year from 1994 to 2011 was 20. There were 6% more female patients (205 of 387; 53%) than male (182 of 387; 47%). Of the cases in which the perpetrator of the violence against a female patient was specified (111 of 205 female cases), 74% (82 of 111) were the patient's husband. Only 5% (5 of 111) of cases in females were inflicted by another female. This analysis provides the best available information on domestic violence cases requiring a visit to a tertiary hospital in a Pacific Island in the specified time period and is undoubtedly an under-estimate of the total cases of domestic violence. Preventing and treating domestic violence in the Solomon Islands and in the Pacific is an important challenge and there is a significant role for secondary and tertiary health services in screening for and preventing domestic violence. PMID:25285254

  5. Hospital Visits Due to Domestic Violence from 1994 to 2011 in the Solomon Islands: A Descriptive Case Series

    PubMed Central

    Negin, Joel; Houasia, Patrick; Munamua, Alex B; Leon, David P; Rimon, Mia; Martiniuk, Alexandra LC

    2014-01-01

    The Solomon Islands has one of the highest rates of domestic violence in the world. This paper is a descriptive case series of all cases of domestic violence presenting to the Solomon Islands National Referral Hospital (NRH) over 18 years. Data were routinely collected from a database of all patients who were treated by NRH general surgery and orthopedic clinicians between 1994 and 2011, inclusive. The total number of cases in the injury database as a result of domestic violence was 387. The average number of cases in the database per year from 1994 to 2011 was 20. There were 6% more female patients (205 of 387; 53%) than male (182 of 387; 47%). Of the cases in which the perpetrator of the violence against a female patient was specified (111 of 205 female cases), 74% (82 of 111) were the patient's husband. Only 5% (5 of 111) of cases in females were inflicted by another female. This analysis provides the best available information on domestic violence cases requiring a visit to a tertiary hospital in a Pacific Island in the specified time period and is undoubtedly an under-estimate of the total cases of domestic violence. Preventing and treating domestic violence in the Solomon Islands and in the Pacific is an important challenge and there is a significant role for secondary and tertiary health services in screening for and preventing domestic violence. PMID:25285254

  6. Biocultural interpretations of trauma in two prehistoric Pacific Island populations from Papua New Guinea and the Solomon Islands.

    PubMed

    Scott, Rachel M; Buckley, Hallie R

    2010-08-01

    Two Pacific Island skeletal samples originating from the inland site of Nebira, Papua New Guinea (1230-1650) and a coastal site on the small island of Taumako, Solomon Islands (1530-1698) were examined for evidence of skeletal trauma using a biocultural approach. The types of trauma identified were cranial trauma, postcranial fractures, and piercing and sharp force trauma. Both samples exhibit trauma (Nebira, n = 9/28, 32.1%; Taumako, n = 17/133, 12.8%). Postcranial fractures are significantly higher in males from Nebira (Fisher Exact P value = 0.025). The prevalence of cranial trauma (n = 6/28, 21.4%) is significantly higher in Nebira individuals (Fisher Exact P value = 0.007). There is no conclusive evidence of piercing trauma at Nebira unlike Taumako, which has four individuals with evidence of piercing or sharp force trauma. Both samples show evidence of interpersonal violence and warfare. The results suggest the environment may have contributed to the pattern of trauma at these sites. These patterns are discussed within their cultural and environmental contexts.

  7. Community perceptions of mental health needs: a qualitative study in the Solomon Islands

    PubMed Central

    Blignault, Ilse; Bunde-Birouste, Anne; Ritchie, Jan; Silove, Derrick; Zwi, Anthony B

    2009-01-01

    Background Psychosocial and mental health needs in the aftermath of conflict and disaster have attracted substantial attention. In the Solomon Islands, the conceptualisation of mental health, for several decades regarded by policy makers as primarily a health issue, has broadened and been incorporated into the national development and social policy agendas, reflecting recognition of the impact of conflict and rapid social change on the psychosocial wellbeing of the community as a whole. We sought to understand how mental health and psychosocial wellbeing were seen at the community level, the extent to which these issues were identified as being associated with periods of 'tension', violence and instability, and the availability of traditional approaches and Ministry of Health services to address these problems. Methods This article reports the findings of qualitative research conducted in a rural district on the island of Guadalcanal in the Solomon Islands. Key informant interviews were conducted with community leaders, and focus groups were held with women, men and young people. Wellbeing was defined broadly. Results Problems of common concern included excessive alcohol and marijuana use, interpersonal violence and abuse, teenage pregnancy, and lack of respect and cooperation. Troubled individuals and their families sought help for mental problems from various sources including chiefs, church leaders and traditional healers and, less often, trauma support workers, health clinic staff and police. Substance-related problems presented special challenges, as there were no traditional solutions at the individual or community level. Severe mental illness was also a challenge, with few aware that a community mental health service existed. Contrary to our expectations, conflict-related trauma was not identified as a major problem by the community who were more concerned about the economic and social sequelae of the conflict. Conclusion Communities identify and are

  8. A new species of Abyssocladia (Porifera, Demospongiae, Poecilosclerida, Cladorhizidae) and other carnivorous sponges from the far eastern Solomon Islands.

    PubMed

    Vacelet, Jean; Kelly, Michelle

    2014-01-01

    Two species, one each of Abyssocladia Lévi, 1964, and Asbestopluma Topsent, 1901, are recorded from the far eastern Solomon Islands for the first time. Abyssocladia lakwollii sp. nov. is characterized by the pedunculate disc-shape of the body, the unusually large size of the isochelae I microscleres, and by the shape of the cleistochelae with crossed central teeth. Asbestopluma (A.) desmophora Kelly & Vacelet, 2011, first described from a seamount on Macquarie Ridge (Australia EEZ) and eastern waters to the north and south of New Zealand, is also recorded from the far eastern Solomon Islands. The specimens differ only slightly from their southern counterparts in dimensions of some spicules, and in the ornamentation detail of the basal teeth of the large and small anisochelae.  PMID:24943621

  9. A new species of Abyssocladia (Porifera, Demospongiae, Poecilosclerida, Cladorhizidae) and other carnivorous sponges from the far eastern Solomon Islands.

    PubMed

    Vacelet, Jean; Kelly, Michelle

    2014-06-16

    Two species, one each of Abyssocladia Lévi, 1964, and Asbestopluma Topsent, 1901, are recorded from the far eastern Solomon Islands for the first time. Abyssocladia lakwollii sp. nov. is characterized by the pedunculate disc-shape of the body, the unusually large size of the isochelae I microscleres, and by the shape of the cleistochelae with crossed central teeth. Asbestopluma (A.) desmophora Kelly & Vacelet, 2011, first described from a seamount on Macquarie Ridge (Australia EEZ) and eastern waters to the north and south of New Zealand, is also recorded from the far eastern Solomon Islands. The specimens differ only slightly from their southern counterparts in dimensions of some spicules, and in the ornamentation detail of the basal teeth of the large and small anisochelae. 

  10. Resumption of traditional drive hunting of dolphins in the Solomon Islands in 2013.

    PubMed

    Oremus, Marc; Leqata, John; Baker, C Scott

    2015-05-01

    The 'drive hunting' of dolphins has a long history in the Solomon Islands, specifically at the island of Malaita. In 2010, the most active village, Fanalei, suspended hunting in exchange for financial compensation from an international non-governmental organization but resumed hunting again in early 2013. Here, we report on a visit to Fanalei in March 2013 to document the species and number of dolphins killed in the renewed hunting. Detailed records for the 2013 hunting, up to the time of our visit, included at least 1500 pantropical spotted dolphins (Stenella attenuata), 159 spinner dolphins (Stenella longirostris) and 15 'bottlenose' dolphins, probably Tursiops truncatus. Molecular identification confirmed two of the species, pantropical spotted and spinner dolphins. A summary of all available records from 1976 to 2013 documented a minimum total of 15 454 dolphins killed by the Fanalei villagers alone. We also found the local price of a dolphin tooth had increased from about US$0.14 (SBD$1) in 2004 to about US$0.70 (SBD$5) in 2013. The large number of dolphins killed and the apparent incentive for future hunting offered by the increasing commercial value of teeth, highlight an urgent need to monitor hunts and assess the abundance and trends in local populations. PMID:26064656

  11. Resumption of traditional drive hunting of dolphins in the Solomon Islands in 2013.

    PubMed

    Oremus, Marc; Leqata, John; Baker, C Scott

    2015-05-01

    The 'drive hunting' of dolphins has a long history in the Solomon Islands, specifically at the island of Malaita. In 2010, the most active village, Fanalei, suspended hunting in exchange for financial compensation from an international non-governmental organization but resumed hunting again in early 2013. Here, we report on a visit to Fanalei in March 2013 to document the species and number of dolphins killed in the renewed hunting. Detailed records for the 2013 hunting, up to the time of our visit, included at least 1500 pantropical spotted dolphins (Stenella attenuata), 159 spinner dolphins (Stenella longirostris) and 15 'bottlenose' dolphins, probably Tursiops truncatus. Molecular identification confirmed two of the species, pantropical spotted and spinner dolphins. A summary of all available records from 1976 to 2013 documented a minimum total of 15 454 dolphins killed by the Fanalei villagers alone. We also found the local price of a dolphin tooth had increased from about US$0.14 (SBD$1) in 2004 to about US$0.70 (SBD$5) in 2013. The large number of dolphins killed and the apparent incentive for future hunting offered by the increasing commercial value of teeth, highlight an urgent need to monitor hunts and assess the abundance and trends in local populations.

  12. Keeping Food on the Table: Human Responses and Changing Coastal Fisheries in Solomon Islands

    PubMed Central

    2015-01-01

    Globally the majority of commercial fisheries have experienced dramatic declines in stock and catch. Likewise, projections for many subsistence fisheries in the tropics indicate a dramatic decline is looming in the coming decades. In the Pacific Islands coastal fisheries provide basic subsistence needs for millions of people. A decline in fish catch would therefore have profound impacts on the health and livelihoods of these coastal communities. Given the decrease in local catch rates reported for many coastal communities in the Pacific, it is important to understand if fishers have responded to ecological change (either by expanding their fishing range and/or increasing their fishing effort), and if so, to evaluate the costs or benefits of these responses. We compare data from fish catches in 1995 and 2011 from a rural coastal community in Solomon Islands to examine the potentially changing coastal reef fishery at these time points. In particular we found changes in preferred fishing locations, fishing methodology and catch composition between these data sets. The results indicate that despite changes in catch rates (catch per unit effort) between data collected in 2011 and 16 years previously, the study community was able to increase gross catches through visiting fishing sites further away, diversifying fishing methods and targeting pelagic species through trolling. Such insight into local-scale responses to changing resources and/or fisheries development will help scientists and policy makers throughout the Pacific region in managing the region’s fisheries in the future. PMID:26158694

  13. Establishing an early warning alert and response network following the Solomon Islands tsunami in 2013

    PubMed Central

    Bilve, Augustine; Nogareda, Francisco; Joshua, Cynthia; Ross, Lester; Betcha, Christopher; Durski, Kara; Fleischl, Juliet

    2014-01-01

    Abstract Problem On 6 February 2013, an 8.0 magnitude earthquake generated a tsunami that struck the Santa Cruz Islands, Solomon Islands, killing 10 people and displacing over 4700. Approach A post-disaster assessment of the risk of epidemic disease transmission recommended the implementation of an early warning alert and response network (EWARN) to rapidly detect, assess and respond to potential outbreaks in the aftermath of the tsunami. Local setting Almost 40% of the Santa Cruz Islands’ population were displaced by the disaster, and living in cramped temporary camps with poor or absent sanitation facilities and insufficient access to clean water. There was no early warning disease surveillance system. Relevant changes By 25 February, an EWARN was operational in five health facilities that served 90% of the displaced population. Eight priority diseases or syndromes were reported weekly; unexpected health events were reported immediately. Between 25 February and 19 May, 1177 target diseases or syndrome cases were reported. Seven alerts were investigated. No sustained transmission or epidemics were identified. Reporting compliance was 85%. The EWARN was then transitioned to the routine four-syndrome early warning disease surveillance system. Lesson learnt It was necessary to conduct a detailed assessment to evaluate the risk and potential impact of serious infectious disease outbreaks, to assess whether and how enhanced early warning disease surveillance should be implemented. Local capacities and available resources should be considered in planning EWARN implementation. An EWARN can be an opportunity to establish or strengthen early warning disease surveillance capabilities. PMID:25378746

  14. Keeping Food on the Table: Human Responses and Changing Coastal Fisheries in Solomon Islands.

    PubMed

    Albert, Simon; Aswani, Shankar; Fisher, Paul L; Albert, Joelle

    2015-01-01

    Globally the majority of commercial fisheries have experienced dramatic declines in stock and catch. Likewise, projections for many subsistence fisheries in the tropics indicate a dramatic decline is looming in the coming decades. In the Pacific Islands coastal fisheries provide basic subsistence needs for millions of people. A decline in fish catch would therefore have profound impacts on the health and livelihoods of these coastal communities. Given the decrease in local catch rates reported for many coastal communities in the Pacific, it is important to understand if fishers have responded to ecological change (either by expanding their fishing range and/or increasing their fishing effort), and if so, to evaluate the costs or benefits of these responses. We compare data from fish catches in 1995 and 2011 from a rural coastal community in Solomon Islands to examine the potentially changing coastal reef fishery at these time points. In particular we found changes in preferred fishing locations, fishing methodology and catch composition between these data sets. The results indicate that despite changes in catch rates (catch per unit effort) between data collected in 2011 and 16 years previously, the study community was able to increase gross catches through visiting fishing sites further away, diversifying fishing methods and targeting pelagic species through trolling. Such insight into local-scale responses to changing resources and/or fisheries development will help scientists and policy makers throughout the Pacific region in managing the region's fisheries in the future. PMID:26158694

  15. The energetic 2010 MW 7.1 Solomon Islands tsunami earthquake

    NASA Astrophysics Data System (ADS)

    Newman, Andrew V.; Feng, Lujia; Fritz, Hermann M.; Lifton, Zachery M.; Kalligeris, Nikos; Wei, Yong

    2011-08-01

    On 2010 January 3 a moment magnitude MW 7.1 earthquake struck the Solomon Islands very near the San Cristobal trench, causing extensive landslides and surprisingly large tsunami waves. Because of the unique proximity of islands to the trench (<20 km) and earthquake, a post-seismic survey successfully identified unexpected widespread coseismic subsidence towards the trench (up to 80 cm), with no discernable post-seismic deformation. Approximately 1000 km from the earthquake ocean-bottom pressure sensors measured 1-2 cm open-ocean tsunami waves. Though spatially limited, the local tsunami wave heights up to 7 m were comparable to the much larger adjacent 2007 MW 8.1 earthquake. The seismically determined focal mechanism, broad-scale subsidence, tsunami amplitude and open ocean wave heights are all explained by an extremely shallow low-angle thrust adjacent to the impinging subduction of the two seamounts near the trench. This event belongs to a potentially new class of shallow 'tsunami earthquakes' that is not identified as deficient in radiated seismic energy.

  16. Resumption of traditional drive hunting of dolphins in the Solomon Islands in 2013

    PubMed Central

    Oremus, Marc; Leqata, John; Baker, C. Scott

    2015-01-01

    The ‘drive hunting’ of dolphins has a long history in the Solomon Islands, specifically at the island of Malaita. In 2010, the most active village, Fanalei, suspended hunting in exchange for financial compensation from an international non-governmental organization but resumed hunting again in early 2013. Here, we report on a visit to Fanalei in March 2013 to document the species and number of dolphins killed in the renewed hunting. Detailed records for the 2013 hunting, up to the time of our visit, included at least 1500 pantropical spotted dolphins (Stenella attenuata), 159 spinner dolphins (Stenella longirostris) and 15 ‘bottlenose’ dolphins, probably Tursiops truncatus. Molecular identification confirmed two of the species, pantropical spotted and spinner dolphins. A summary of all available records from 1976 to 2013 documented a minimum total of 15 454 dolphins killed by the Fanalei villagers alone. We also found the local price of a dolphin tooth had increased from about US$0.14 (SBD$1) in 2004 to about US$0.70 (SBD$5) in 2013. The large number of dolphins killed and the apparent incentive for future hunting offered by the increasing commercial value of teeth, highlight an urgent need to monitor hunts and assess the abundance and trends in local populations. PMID:26064656

  17. Keeping Food on the Table: Human Responses and Changing Coastal Fisheries in Solomon Islands.

    PubMed

    Albert, Simon; Aswani, Shankar; Fisher, Paul L; Albert, Joelle

    2015-01-01

    Globally the majority of commercial fisheries have experienced dramatic declines in stock and catch. Likewise, projections for many subsistence fisheries in the tropics indicate a dramatic decline is looming in the coming decades. In the Pacific Islands coastal fisheries provide basic subsistence needs for millions of people. A decline in fish catch would therefore have profound impacts on the health and livelihoods of these coastal communities. Given the decrease in local catch rates reported for many coastal communities in the Pacific, it is important to understand if fishers have responded to ecological change (either by expanding their fishing range and/or increasing their fishing effort), and if so, to evaluate the costs or benefits of these responses. We compare data from fish catches in 1995 and 2011 from a rural coastal community in Solomon Islands to examine the potentially changing coastal reef fishery at these time points. In particular we found changes in preferred fishing locations, fishing methodology and catch composition between these data sets. The results indicate that despite changes in catch rates (catch per unit effort) between data collected in 2011 and 16 years previously, the study community was able to increase gross catches through visiting fishing sites further away, diversifying fishing methods and targeting pelagic species through trolling. Such insight into local-scale responses to changing resources and/or fisheries development will help scientists and policy makers throughout the Pacific region in managing the region's fisheries in the future.

  18. Education and Libraries in the Solomon Islands: A Bibliography of English-Language Books, Documents, Papers, Theses and Dissertations and Journal Articles.

    ERIC Educational Resources Information Center

    Sperry, Robert

    The Solomon Islands are a scattered Melanesian archipelago in the southwestern Pacific Ocean. There are 21 large islands and numerous smaller ones with a total population of 285,766 in 1986. About two-thirds of school-age children attend organized schools. The literacy rate of the islands was reported at 17 percent in 1980. Approximately 30…

  19. Crustal deformation in the Western Solomon Islands revealed by GPS observation and D_InSAR during 2009 - 2013

    NASA Astrophysics Data System (ADS)

    Kuo, Y. T.; Ku, C. S.; Wang, Y.; Lin, Y. N. N. N.; Chen, Y. G.; Lin, K. C.; Huang, B. S.; Hsu, Y. J.; Taylor, F. W.

    2014-12-01

    The Solomon Islands are located in the southwestern Pacific, where the Australian Plate underthrusts the Solomon Plate towards ~N70 E at a rate of ~100 mm/yr. The Coleman seamount on the Australian plate is impinging on the forearc at Rendova Island and may cause both the seismicity and tectonic behavior to be more complicated than usual. Hence, an understanding o f the ongoing crustal deformation is essential to reconstructing the structural framework that controls the entire subduction system, particularly earthquake generation on the megathrust fault and possible subsidiary faults. Based on the results from GPS and D_InSAR, the horizontal velocity profiles across the trench for areas of the forearc to the west and to the east of the impinging Coleman seamount show different characteristics. The eastern profile shows convergence rates of ~100 mm/yr only 10 km from the trench at the western end of the Tetepare Island, and the western profile reaches 70 mm/yr at 30 km from the trench. This difference might be caused by the shallow locked depth consistent with co-seismic slip located extremely close to the trench during the Mw 7.1 Solomon Earthquake on 3rd January, 2010. We have a hypothesis to argue that the behavior of the fault geometry should be very different on the two sides of the seamount. However, the coupling ratio could be realized by further detailed analysis.

  20. The accuracy of clinical malaria case reporting at primary health care facilities in Honiara, Solomon Islands

    PubMed Central

    Kunimitsu, Ayano

    2009-01-01

    Background The accuracy of malaria case reporting is challenging due to restricted human and material resources in many countries. The reporting often depends on the clinical diagnosis because of the scarcity of microscopic examinations. Particularly, clinical malaria case reporting by primary health care facilities (local clinics), which constitutes the baseline data of surveillance, has never previously been sufficiently evaluated. In order to improve the malaria reporting system to the level required to eventually eliminate this disease, this study estimates the gaps between the records of clinics and government statistics regarding the incidence of clinical malaria, and then also examines some factors that might explain the data discrepancy, including such variables as clinic staffing and record keeping. Methods All medical records for outpatients in 2007, handwritten by nurses, were collected from local clinics in Honiara, the capital of the Solomon Islands. The all-monthly clinical malaria cases were then recalculated. The corresponding monthly data in official statistics were provided by the government. Next, in order to estimate any data discrepancy, the ratio of the cases recorded at clinics to the cases reported to the government was determined on the monthly basis. Finally, the associations between the monthly discrepancy and other variables were evaluated by a multiple regression analysis. Results The mean data discrepancy between the records of clinics and government statistics was 21.2% (n = 96). Significant associations were observed between the discrepancy and the average number of patients (coefficient: 0.05, 95%CI: 0.31, 0.07), illegible handwriting (coefficient: 0.09, 95%CI: 0.04, 0.15), the use of tally sheets (coefficient:-0.38, 95%CI: -0.54, -0.22), and the clinic level (coefficient:-0.48, 95%CI:-0.89,-0.06). Conclusion The findings of this study demonstrate the huge data discrepancy between the records of clinics and government statistics in

  1. Exploring provider and community responses to the new malaria diagnostic and treatment regime in Solomon Islands

    PubMed Central

    2011-01-01

    Background Improvements in availability and accessibility of artemisinin-based combination therapy (ACT) for malaria treatment and the emergence of multi-drug-resistant parasites have prompted many countries to adopt ACT as the first-line drug. In 2009, Solomon Islands (SI) likewise implemented new national treatment guidelines for malaria. The ACT, Coartem® (artemether-lumefantrine) is now the primary pharmacotherapy in SI for Plasmodium falciparum malaria, Plasmodium vivax malaria or mixed infections. Targeted treatment is also recommended in the new treatment regime through maintenance of quality microscopy services and the introduction of Rapid Diagnostic Tests (RDTs). Ascertaining the factors that influence community and provider acceptance of and adherence to the new treatment regime will be vital to improving the effectiveness of this intervention and reducing the risk of development of drug resistance. Methods In order to understand community and prescriber perceptions and acceptability of the new diagnostic and treatment interventions, 12 focus group discussions (FGDs) and 12 key informant interviews (KII) were carried out in rural and urban villages of Malaita Province, Solomon Islands four months subsequent to roll out of these interventions. Results Lack of access to microscopy or distrust in the accuracy of diagnostic tools were reported by some participants as reasons for the ongoing practice of presumptive treatment of malaria. Lack of confidence in RDT accuracy has negatively impacted its acceptability. Coartem® had good acceptability among most participants, however, some rural participants questioned its effectiveness due to lack of side effects and the larger quantity of tablets required to be taken. Storing of left over medication for subsequent fever episodes was reported as common. Conclusion To address these issues, further training and supportive supervision of healthcare workers will be essential, as will the engagement of influential

  2. Solomon Islands largest hawksbill turtle rookery shows signs of recovery after 150 years of excessive exploitation.

    PubMed

    Hamilton, Richard J; Bird, Tomas; Gereniu, Collin; Pita, John; Ramohia, Peter C; Walter, Richard; Goerlich, Clara; Limpus, Colin

    2015-01-01

    The largest rookery for hawksbill turtles in the oceanic South Pacific is the Arnavon Islands, which are located in the Manning Strait between Isabel and Choiseul Province, Solomon Islands. The history of this rookery is one of overexploitation, conflict and violence. Throughout the 1800s Roviana headhunters from New Georgia repeatedly raided the Manning Strait to collect hawksbill shell which they traded with European whalers. By the 1970s the Arnavons hawksbill population was in severe decline and the national government intervened, declaring the Arnavons a sanctuary in 1976. But this government led initiative was short lived, with traditional owners burning down the government infrastructure and resuming intensive harvesting in 1982. In 1991 routine beach monitoring and turtle tagging commenced at the Arnavons along with extensive community consultations regarding the islands' future, and in 1995 the Arnavon Community Marine Conservation Area (ACMCA) was established. Around the same time national legislation banning the sale of all turtle products was passed. This paper represents the first analysis of data from 4536 beach surveys and 845 individual turtle tagging histories obtained from the Arnavons between 1991-2012. Our results and the results of others, reveal that many of the hawksbill turtles that nest at the ACMCA forage in distant Australian waters, and that nesting on the Arnavons occurs throughout the year with peak nesting activity coinciding with the austral winter. Our results also provide the first known evidence of recovery for a western pacific hawksbill rookery, with the number of nests laid at the ACMCA and the remigration rates of turtles doubling since the establishment of the ACMCA in 1995. The Arnavons case study provides an example of how changes in policy, inclusive community-based management and long term commitment can turn the tide for one of the most charismatic and endangered species on our planet.

  3. Solomon Islands largest hawksbill turtle rookery shows signs of recovery after 150 years of excessive exploitation.

    PubMed

    Hamilton, Richard J; Bird, Tomas; Gereniu, Collin; Pita, John; Ramohia, Peter C; Walter, Richard; Goerlich, Clara; Limpus, Colin

    2015-01-01

    The largest rookery for hawksbill turtles in the oceanic South Pacific is the Arnavon Islands, which are located in the Manning Strait between Isabel and Choiseul Province, Solomon Islands. The history of this rookery is one of overexploitation, conflict and violence. Throughout the 1800s Roviana headhunters from New Georgia repeatedly raided the Manning Strait to collect hawksbill shell which they traded with European whalers. By the 1970s the Arnavons hawksbill population was in severe decline and the national government intervened, declaring the Arnavons a sanctuary in 1976. But this government led initiative was short lived, with traditional owners burning down the government infrastructure and resuming intensive harvesting in 1982. In 1991 routine beach monitoring and turtle tagging commenced at the Arnavons along with extensive community consultations regarding the islands' future, and in 1995 the Arnavon Community Marine Conservation Area (ACMCA) was established. Around the same time national legislation banning the sale of all turtle products was passed. This paper represents the first analysis of data from 4536 beach surveys and 845 individual turtle tagging histories obtained from the Arnavons between 1991-2012. Our results and the results of others, reveal that many of the hawksbill turtles that nest at the ACMCA forage in distant Australian waters, and that nesting on the Arnavons occurs throughout the year with peak nesting activity coinciding with the austral winter. Our results also provide the first known evidence of recovery for a western pacific hawksbill rookery, with the number of nests laid at the ACMCA and the remigration rates of turtles doubling since the establishment of the ACMCA in 1995. The Arnavons case study provides an example of how changes in policy, inclusive community-based management and long term commitment can turn the tide for one of the most charismatic and endangered species on our planet. PMID:25853880

  4. American Dissertations on Foreign Education: A Bibliography with Abstracts. Volume XVII. Pacific: American Samoa, Fiji, Guam, Papua New Guinea, Ryukyu Islands, Solomon Islands, Tonga, Trust Territory of the Pacific Islands (Micronesia), Tubuai (French Polynesia), Western Samoa.

    ERIC Educational Resources Information Center

    Parker, Franklin, Ed.; Parker, Betty June, Ed.

    The editors attempt to examine and abstract all locatable doctoral dissertations completed in the United States, Canada, and some European countries that pertain to the Pacific area. Specifically, these dissertations deal with American Samoa, Fiji, Guam, Papua New Guinea, Ryukyu Islands, Solomon Islands, Tonga, Trust Territory of the Pacific…

  5. Changing patterns of hypertension, diabetes, obesity and diet among Melanesians and Micronesians in the Solomon Islands.

    PubMed

    Eason, R J; Pada, J; Wallace, R; Henry, A; Thornton, R

    1987-05-01

    A cross-sectional survey of diabetes, hypertension, obesity and dietary patterns has been conducted in the Western Province of the Solomon Islands. Three groups--traditional and more urbanized Melanesians and semitraditional Micronesians--were compared. Abnormal glucose tolerance was rare (less than 1% over all) in Melanesians regardless of acculturation, but was present in 9.7% of adult Micronesians in whom it was associated with age; obesity; female sex; and a diet that was high in energy and refined carbohydrates. Hypertension, which was associated with advancing age and obesity, was recorded in 6.0% and 8.3% of traditional and partly urbanized Melanesians, respectively, and in 4.8% of Micronesians. Systolic and diastolic blood pressures correlated significantly with age for all except traditional Melanesian women among whom the association was limited to the systolic blood pressure only. Significant correlation coefficients were recorded between diastolic blood pressure and body mass index for both sexes and all groups, and between systolic blood pressure and body mass index for all women but only for Micronesian men. Dramatic differences in life-style and dietary patterns are described for rural and more urbanized Melanesians among whom the mean daily urinary sodium outputs were 67 and 119 mmol/L, respectively. PMID:3497330

  6. The contribution of nearshore fish aggregating devices (FADs) to food security and livelihoods in Solomon Islands.

    PubMed

    Albert, Joelle A; Beare, Doug; Schwarz, Anne-Maree; Albert, Simon; Warren, Regon; Teri, James; Siota, Faye; Andrew, Neil L

    2014-01-01

    Fish aggregating devices, or FADs, are used widely in developing countries to concentrate pelagic fish, making them easier to catch. Nearshore FADs anchored close to the coast allow access for rural communities, but despite their popularity among policy makers, there is a dearth of empirical analysis of their contributions to the supply of fish and to fisheries management. In this paper we demonstrate that nearshore FADs increased the supply of fish to four communities in Solomon Islands. Estimated total annual fish catch ranged from 4300 to 12,000 kg across the study villages, with nearshore FADs contributing up to 45% of the catch. While it is clear that FADs increased the supply of fish, FAD catch rates were not consistently higher than other fishing grounds. Villages with limited access to diverse or productive fishing grounds seemingly utilized FADs to better effect. Villagers believed FADs increased household income and nutrition, as well as providing a source of fish for community events. FADs were also perceived to increase intra-household conflict and reduce fishers' participation in community activities. FADs need to be placed within a broader rural development context and treated as another component in the diversified livelihoods of rural people; as with other livelihood options they bring trade-offs and risks. PMID:25513808

  7. Ongoing outbreak of dengue serotype-3 in Solomon Islands, January to May 2013

    PubMed Central

    Joshua, Cynthia; Sio, Alison; Shortus, Matthew; Dalipanda, Tenneth; Durski, Kara; Musto, Jennie; Puiahi, Elliot; Dofai, Alfred; Aaskov, John; Cao-Lormeau, Van Mai; Musso, Didier; Dutta, Nick; Fleisch, Juliet; Nilles, Eric

    2013-01-01

    Methods Enhanced dengue surveillance was implemented in the capital, Honiara, and in the provinces. This included training health staff on dengue case definitions, data collection and reporting. Vector surveillance was also conducted. Results From 3 January to 15 May 2013, 5254 cases of suspected dengue were reported (101.8 per 10 000 population), including 401 hospitalizations and six deaths. The median age of cases was 20 years (range zero to 90), and 86% were reported from Honiara. Both Aedes aegyti and Aedes albopictus were identified in Honiara. Outbreak response measures included clinical training seminars, vector control activities, implementation of diagnostic and case management protocols and a public communication campaign. Discussion This was the first large dengue outbreak documented in Solomon Islands. Factors that may have contributed to this outbreak include a largely susceptible population, the presence of a highly efficient dengue vector in Honiara, a high-density human population with numerous breeding sites and favourable weather conditions for mosquito proliferation. Although the number of cases has plateaued since 1 April, continued enhanced nationwide surveillance and response activities are necessary. PMID:24319611

  8. The Contribution of Nearshore Fish Aggregating Devices (FADs) to Food Security and Livelihoods in Solomon Islands

    PubMed Central

    Albert, Joelle A.; Beare, Doug; Schwarz, Anne-Maree; Albert, Simon; Warren, Regon; Teri, James; Siota, Faye; Andrew, Neil L.

    2014-01-01

    Fish aggregating devices, or FADs, are used widely in developing countries to concentrate pelagic fish, making them easier to catch. Nearshore FADs anchored close to the coast allow access for rural communities, but despite their popularity among policy makers, there is a dearth of empirical analysis of their contributions to the supply of fish and to fisheries management. In this paper we demonstrate that nearshore FADs increased the supply of fish to four communities in Solomon Islands. Estimated total annual fish catch ranged from 4300 to 12 000 kg across the study villages, with nearshore FADs contributing up to 45% of the catch. While it is clear that FADs increased the supply of fish, FAD catch rates were not consistently higher than other fishing grounds. Villages with limited access to diverse or productive fishing grounds seemingly utilized FADs to better effect. Villagers believed FADs increased household income and nutrition, as well as providing a source of fish for community events. FADs were also perceived to increase intra-household conflict and reduce fishers' participation in community activities. FADs need to be placed within a broader rural development context and treated as another component in the diversified livelihoods of rural people; as with other livelihood options they bring trade-offs and risks. PMID:25513808

  9. An outbreak investigation of congenital rubella syndrome in Solomon Islands, 2013

    PubMed Central

    Durski, Kara N; Tituli, Carol; Ogaoga, Divi; Joshua, Cynthia; Dofai, Alfred; Leydon, Jennie; Nilles, Eric

    2016-01-01

    Introduction During May 2012, a rubella outbreak was declared in Solomon Islands. A suspected case of congenital rubella syndrome (CRS) was reported from one hospital 11 months later in 2013. This report describes the subsequent CRS investigation, findings and measures implemented. Methods Prospective CRS surveillance was conducted at the newborn nursery, paediatric and post-natal wards, and the paediatric cardiology and ophthalmology clinics of the study hospital from April to July 2013. Retrospective case finding by reviewing medical records was also undertaken to identify additional cases born between January and March 2013 for the same wards and clinics. Cases were identified using established World Health Organization case definitions for CRS. Results A total of 13 CRS cases were identified, including two laboratory-confirmed, four clinically confirmed and seven suspected cases. Five CRS cases were retrospectively identified, including four suspected and one clinically confirmed case. There was no geospatial clustering of residences. The mothers of the cases were aged between 20 and 36 years. Three of the six mothers available for interview recalled an acute illness with rash during the first trimester of pregnancy. Discussion Additional CRS cases not captured in this investigation are likely. Caring for CRS cases is a challenge in resource-poor settings. Rubella vaccination is safe and effective and can prevent the serious consequences of CRS. Well planned and funded vaccination activities can prevent future CRS cases.

  10. The contribution of nearshore fish aggregating devices (FADs) to food security and livelihoods in Solomon Islands.

    PubMed

    Albert, Joelle A; Beare, Doug; Schwarz, Anne-Maree; Albert, Simon; Warren, Regon; Teri, James; Siota, Faye; Andrew, Neil L

    2014-01-01

    Fish aggregating devices, or FADs, are used widely in developing countries to concentrate pelagic fish, making them easier to catch. Nearshore FADs anchored close to the coast allow access for rural communities, but despite their popularity among policy makers, there is a dearth of empirical analysis of their contributions to the supply of fish and to fisheries management. In this paper we demonstrate that nearshore FADs increased the supply of fish to four communities in Solomon Islands. Estimated total annual fish catch ranged from 4300 to 12,000 kg across the study villages, with nearshore FADs contributing up to 45% of the catch. While it is clear that FADs increased the supply of fish, FAD catch rates were not consistently higher than other fishing grounds. Villages with limited access to diverse or productive fishing grounds seemingly utilized FADs to better effect. Villagers believed FADs increased household income and nutrition, as well as providing a source of fish for community events. FADs were also perceived to increase intra-household conflict and reduce fishers' participation in community activities. FADs need to be placed within a broader rural development context and treated as another component in the diversified livelihoods of rural people; as with other livelihood options they bring trade-offs and risks.

  11. Solomon Islands Largest Hawksbill Turtle Rookery Shows Signs of Recovery after 150 Years of Excessive Exploitation

    PubMed Central

    Hamilton, Richard J.; Bird, Tomas; Gereniu, Collin; Pita, John; Ramohia, Peter C.; Walter, Richard; Goerlich, Clara; Limpus, Colin

    2015-01-01

    The largest rookery for hawksbill turtles in the oceanic South Pacific is the Arnavon Islands, which are located in the Manning Strait between Isabel and Choiseul Province, Solomon Islands. The history of this rookery is one of overexploitation, conflict and violence. Throughout the 1800s Roviana headhunters from New Georgia repeatedly raided the Manning Strait to collect hawksbill shell which they traded with European whalers. By the 1970s the Arnavons hawksbill population was in severe decline and the national government intervened, declaring the Arnavons a sanctuary in 1976. But this government led initiative was short lived, with traditional owners burning down the government infrastructure and resuming intensive harvesting in 1982. In 1991 routine beach monitoring and turtle tagging commenced at the Arnavons along with extensive community consultations regarding the islands’ future, and in 1995 the Arnavon Community Marine Conservation Area (ACMCA) was established. Around the same time national legislation banning the sale of all turtle products was passed. This paper represents the first analysis of data from 4536 beach surveys and 845 individual turtle tagging histories obtained from the Arnavons between 1991-2012. Our results and the results of others, reveal that many of the hawksbill turtles that nest at the ACMCA forage in distant Australian waters, and that nesting on the Arnavons occurs throughout the year with peak nesting activity coinciding with the austral winter. Our results also provide the first known evidence of recovery for a western pacific hawksbill rookery, with the number of nests laid at the ACMCA and the remigration rates of turtles doubling since the establishment of the ACMCA in 1995. The Arnavons case study provides an example of how changes in policy, inclusive community-based management and long term commitment can turn the tide for one of the most charismatic and endangered species on our planet. PMID:25853880

  12. Population genetics of Plasmodium falciparum and Plasmodium vivax and asymptomatic malaria in Temotu Province, Solomon Islands

    PubMed Central

    2013-01-01

    Background Temotu Province, Solomon Islands is progressing toward malaria elimination. A baseline survey conducted in 2008 showed that most Plasmodium infections in the province were of low parasite density and asymptomatic infections. To better understand mechanisms underlying these malaria transmission characteristics genetic diversity and relationships among Plasmodium falciparum and Plasmodium vivax populations in the province were examined. Methods Forty-five P. falciparum and 67 P. vivax samples collected in the 2008 baseline survey were successfully genotyped using eight P. falciparum and seven P. vivax microsatellite markers. Genetic diversity, relationships and distribution of both P. falciparum and P. vivax populations were analysed. Results Plasmodium falciparum population exhibited low diversity with 19 haplotypes identified and had closely related clusters indicating clonal expansion. Interestingly, a dominant haplotype was significantly associated with fever and high parasite density. In contrast, the P. vivax population was highly diverse with 58 haplotypes identified that were not closely related. Parasite populations between different islands in the province showed low genetic differentiation. Conclusion The low diversity and clonal population of P. falciparum population may partially account for clinical immunity developed against illness. However, it is possible that importation of a new P. falciparum strain was the major cause of illness. High diversity in P. vivax population and low relatedness between strains suggested clinical immunity to P. vivax may be maintained by different mechanisms. The genetic diversity, population structure and distribution of strains indicate that transmission of P. falciparum was low, but that of P. vivax was still high in 2008. These data will be useful for assessing changes in malaria transmission resulting from interventions. PMID:24261646

  13. Preliminary Volcano-Hazard Assessment for Gareloi Volcano, Gareloi Island, Alaska

    USGS Publications Warehouse

    Coombs, Michelle L.; McGimsey, Robert G.; Browne, Brandon L.

    2008-01-01

    Gareloi Volcano (178.794 degrees W and 51.790 degrees N) is located on Gareloi Island in the Delarof Islands group of the Aleutian Islands, about 2,000 kilometers west-southwest of Anchorage and about 150 kilometers west of Adak, the westernmost community in Alaska. This small (about 8x10 kilometer) volcano has been one of the most active in the Aleutians since its discovery by the Bering expedition in the 1740s, though because of its remote location, observations have been scant and many smaller eruptions may have gone unrecorded. Eruptions of Gareloi commonly produce ash clouds and lava flows. Scars on the flanks of the volcano and debris-avalanche deposits on the adjacent seafloor indicate that the volcano has produced large landslides in the past, possibly causing tsunamis. Such events are infrequent, occurring at most every few thousand years. The primary hazard from Gareloi is airborne clouds of ash that could affect aircraft. In this report, we summarize and describe the major volcanic hazards associated with Gareloi.

  14. Slip distribution from the 1 April 2007 Solomon Islands earthquake: A unique image of near-trench rupture

    NASA Astrophysics Data System (ADS)

    Chen, Ting; Newman, Andrew V.; Feng, Lujia; Fritz, Hermann M.

    2009-08-01

    We estimate the slip distribution from the M W 8.1 Solomon Islands earthquake in 2007, from two post-seismic surveys measuring uplifted coral and submerged coastal features. The occurrence of islands extremely proximal to the trench and nucleation of rupture allowed for the collection of unprecedented coseismic deformation dataset along a large megathrust earthquake. Using data from the two surveys along the southeastern half of the slip zone within five weeks of the event, we model the elastic dislocation to identify the optimal (29°), and alternate (20°), dip and distribution of thrust along the southern rupture. The vertical deformation, which includes both coseismic and early postseismic deformation, has highly variable and large slip within 25 km of the trench and straddling Ranongga Island. The shallow focus of slip in the near-trench area may explain the locally high tsunami run-up on portions of Simbo Island, however the aseismic contribution of afterslip remains unknown.

  15. New Observations of Seismic Group Velocities in the Western Solomon Islands from Cross-Correlation of Ambient Seismic Noise

    NASA Astrophysics Data System (ADS)

    Ku, C. S.; You, S. H.; Kuo, Y. T.; Huang, B. S.; Wu, Y. M.; Chen, Y. G.; Taylor, F. W.

    2015-12-01

    A MW 8.1 earthquake occurred on 1 April 2007 in the western Solomon Islands. Following this event, a damaging tsunami was induced and hit the Island Gizo where the capital city of Western Province of Solomon Islands located. Several buildings of this city were destroyed and several peoples lost their lives during this earthquake. However, during this earthquake, no near source seismic instrument has been installed in this region. The seismic evaluations for the aftershock sequence, the possible earthquake early warning and tsunami warning were unavailable. For the purpose of knowing more detailed information about seismic activity in this region, we have installed 9 seismic stations (with Trillium 120PA broadband seismometer and Q330S 24bit digitizer) around the rupture zone of the 2007 earthquake since September of 2009. Within a decade, it has been demonstrated both theoretically and experimentally that the Green's function or impulse response between two seismic stations can be retrieved from the cross-correlation of ambient noise. In this study, 6 stations' observations which are more complete during 2011/10 ~ 2012/12 period, were selected for the purpose of the cross-correlation analysis of ambient seismic noise. The group velocities at period 2-20 seconds of 15 station-pairs were extracted by using multiple filter technique (MFT) method. The analyzed results of this study presented significant results of group velocities with higher frequency contents than other studies (20-60 seconds in usually cases) and opened new opportunities to study the shallow crustal structure of the western Solomon Islands.

  16. An Overview of Geodetic Volcano Research in the Canary Islands

    NASA Astrophysics Data System (ADS)

    Fernández, José; González, Pablo J.; Camacho, Antonio G.; Prieto, Juan F.; Brú, Guadalupe

    2015-11-01

    The Canary Islands are mostly characterized by diffuse and scattered volcanism affecting a large area, with only one active stratovolcano, the Teide-Pico Viejo complex (Tenerife). More than 2 million people live and work in the 7,447 km2 of the archipelago, resulting in an average population density three times greater than the rest of Spain. This fact, together with the growth of exposure during the past 40 years, increases volcanic risk with respect previous eruptions, as witnessed during the recent 2011-2012 El Hierro submarine eruption. Therefore, in addition to purely scientific reasons there are economic and population-security reasons for developing and maintaining an efficient volcano monitoring system. In this scenario geodetic monitoring represents an important part of the monitoring system. We describe volcano geodetic monitoring research carried out in the Canary Islands and the results obtained. We consider for each epoch the two main existing constraints: the level of volcanic activity in the archipelago, and the limitations of the techniques available at the time. Theoretical and observational aspects are considered, as well as the implications for operational volcano surveillance. Current challenges of and future perspectives in geodetic volcano monitoring in the Canaries are also presented.

  17. The case for investing in family planning in the Pacific: costs and benefits of reducing unmet need for contraception in Vanuatu and the Solomon Islands

    PubMed Central

    2013-01-01

    Background Unmet need for family planning in the Pacific is among the highest in the world. Better understanding of required investments and associated benefits of increased access to family planning in the Pacific may assist prioritisation and funding. Methods We modelled the costs and associated health, demographic and economic impacts of reducing unmet need for family planning between 2010–2025 in Vanuatu and the Solomon Islands. Baseline data were obtained from census reports, Demographic and Health Surveys, and UN agency reports. Using a demographic modelling program we compared a scenario of “no change in unmet need” with two distinct scenarios: 1) all family planning needs met by 2020; and, 2) all needs met by 2050. Results Meeting family planning needs by 2020 would increase prevalence of modern contraception in 2025 from 36.8 to 65.5% in Vanuatu and 28.5 to 37.6% in the Solomon Islands. Between 2010–2025 the average annual number of unintended pregnancies would decline by 68% in Vanuatu and 50% in the Solomon Islands, and high-risk births would fall by more than 20%, averting 2,573 maternal and infant deaths. Total fertility rates would fall from 4.1 to 2.2 in Vanuatu and 3.5 in the Solomon Islands, contributing to slowed population growth and lower dependency ratios. The direct cost of reducing unmet need by 2020 was estimated to be $5.19 million for Vanuatu and $3.36 million for the Solomon Islands between 2010–2025. Preventing unintended pregnancies would save $112 million in health and education expenditure. Conclusions In small island developing states such as Vanuatu and the Solomon Islands, increasing investment in family planning would contribute to improved maternal and infant outcomes and substantial public sector savings. PMID:23758783

  18. Strengthening capacity for local evidence to inform local responses to HIV in a remote Solomon Islands health service

    PubMed Central

    Redman-MacLaren, Michelle; Timothy-Harrington, Relmah; Asugeni, Rowena; Muse, Elmah; Jimuru, Emmy; Moutoa, Kenny; Speare, Rick

    2015-01-01

    Background Documenting specific knowledge and attitudes about HIV in the culturally diverse nation of Solomon Islands is essential to inform locally targeted public health responses. As part of a large capacity-strengthening project at Atoifi Adventist Hospital in East Kwaio, Solomon Islands, researchers, using a ‘learn-by-doing’ process, worked with participants in public health research methods. Methods Overall, 43 people attended research capacity building workshops in 2011; eight joined the HIV study group. A cross-sectional survey including semi-structured interviews on HIV was conducted by the group. In February 2014, a hospital administrator was interviewed about how the 2011 study informed local HIV responses. Results Of the 53 survey participants, 64% self-assessed as having little or no HIV knowledge, but 90% knew HIV could be transmitted between men and women during sex. Less than 50% knew HIV could be transmitted between two men having sex, 45% thought HIV could be transmitted by mosquitoes and 55% agreed condoms help protect from HIV. Most participants reported negative attitudes towards people with HIV. Three years later the health administrator reported ad hoc responses to HIV because of low HIV prevalence, increasing noncommunicable diseases, staff turnover and resource shortages. Discussion This HIV study was used to strengthen research skills in local health professionals and community members in Solomon Islands. It showed that community members require accurate information about HIV transmission and that entrenched stigma is an issue. Although results provided local evidence for local response, ongoing health system challenges and little local HIV transmission meant HIV services remain rudimentary. PMID:26306218

  19. Investigating Rainfall Variability in the South Pacific Convergence Zone using the Geochemistry of Stalagmites from the Solomon Islands

    NASA Astrophysics Data System (ADS)

    Sekhon, N.; Quinn, T. M.; Partin, J. W.; Edwards, R. L.; Cheng, H.

    2015-12-01

    The South Pacific Convergence Zone (SPCZ), which extends southeastward from New Guinea to Tahiti, is the largest perennial rainfall feature in the Southern Hemisphere. The position of the SPCZ and its associated rainfall varies significantly on multidecadal timescales, as documented by instrumental and climate proxy data. For example, stalagmite δ18O records (rainfall proxy) from Espiritu Santo, Vanuatu (Partin et al., 2013) and Guadalcanal, Solomon Islands (Maupin et al., 2014), document large (~1‰), abrupt changes in stalagmite δ18O on multidecadal timescales over the past 600 years that arise from internal variability in the climate system. The proxy data agree with the type of rainfall changes observed in the instrumental record, such as the change across 1976/77, but the older changes are larger in relative magnitude. We expand on these earlier studies of rainfall variability in the SPCZ system using stable isotope variations in stalagmites from two other locations in the Solomon Islands (Munda, New Georgia, 8.3°S, 157.3°E; Suku, Nggela Pile (9.8° S, 160.2° E). These stalagmites range in age from about 400 CE to 1850 CE, based on U-Th dating, and have relatively fast growth rates (60 to 300 µm/yr). Stalagmite δ18O time series were generated from sub-samples milled every 500 µm, or approximately 1 to 8 years per data point. Initial results from these two new Solomon Island stalagmites not only confirm the presence of multidecadal variability in stalagmite δ18O identified in previous studies, but suggest that the same amplitude of variability has occurred over several windows of time during the past 1600 years. When complete, these new proxy rainfall records from Munda and Suku will further constrain the pattern and mechanism of SPCZ rainfall variability in western tropical Pacific region.

  20. Decision-makers, donors and data: factors influencing the development of mental health and psychosocial policy in the Solomon Islands.

    PubMed

    Zwi, Anthony B; Blignault, Ilse; Bunde-Birouste, Anne W; Ritchie, Jan E; Silove, Derrick M

    2011-07-01

    Mental disorders and psychosocial problems are common, and present a significant public health burden globally. Increasingly, attention has been devoted to these issues in the aftermath of violent conflict. The Solomon Islands, a small Pacific island nation, has in recent years experienced periods of internal conflict. This article examines how policy decisions regarding mental health and wellbeing were incorporated into the national agenda in the years which followed. The study reveals the policy shifts, contextual influences and players responsible. The Solomon Islands' experience reflects incremental change, built upon longstanding but modest concern with mental health and social welfare issues, reinforced by advocacy from the small mental health team. Armed conflict and ethnic tensions from 1998 to 2003 promoted wider recognition of unmet mental health needs and psychosocial problems. Additional impetus was garnered through the positioning of key health leaders, some of whom were trained in public health. Working together, with an understanding of culture and politics, and drawing on external support, they drove the agenda. Contextual factors, notably further violence and the ongoing risk of instability, a growing youth population, and emerging international and local evidence, also played a part. PMID:21115459

  1. Seismic monitoring at Deception Island volcano (Antarctica): Recent advances

    NASA Astrophysics Data System (ADS)

    Carmona, E.; Almendros, J.; Martín, R.; Cortés, G.; Alguacil, G.; Moreno, J.; Martín, B.; Martos, A.; Serrano, I.; Stich, D.; Ibáñez, J. M.

    2012-04-01

    Deception Island (South Shetland Island, Antarctica) is an active volcano with recent eruptions (e.g. 1967, 1969 and 1970). It is also among the Antarctic sites most visited by tourists. Besides, there are currently two scientific bases operating during the austral summers, usually from late November to early March. For these reasons it is necessary to deploy a volcano monitoring system as complete as possible, designed specifically to endure the extreme conditions of the volcanic environment and the Antarctic climate. The Instituto Andaluz de Geofísica of University of Granada, Spain (IAG-UGR) performs seismic monitoring on Deception Island since 1994 during austral summer surveys. The seismicity basically includes volcano-tectonic earthquakes, long-period events and volcanic tremor, among other signals. The level of seismicity is moderate, except for a seismo-volcanic crisis in 1999. The seismic monitoring system has evolved during these years, following the trends of the technological developments and software improvements. Recent advances have been mainly focused on: (1) the improvement of the seismic network introducing broadband stations and 24-bit data acquisition systems; (2) the development of a short-period seismic array, with a 12-channel, 24-bit data acquisition system; (3) the implementation of wireless data transmission from the network stations and also from the seismic array to a recording center, allowing for real-time monitoring; (4) the efficiency of the power supply systems and the monitoring of the battery levels and power consumption; (5) the optimization of data analysis procedures, including database management, automated event recognition tools for the identification and classification of seismo-volcanic signals, and apparent slowness vector estimates using seismic array data; (6) the deployment of permanent seismic stations and the transmission of data during the winter using a satellite connection. A single permanent station is operating

  2. Solophenols B-D and solomonin: new prenylated polyphenols isolated from propolis collected from the Solomon Islands and their antibacterial activity.

    PubMed

    Inui, Saori; Hosoya, Takahiro; Shimamura, Yuko; Masuda, Shuichi; Ogawa, Takeshi; Kobayashi, Hirokazu; Shirafuji, Kenichi; Moli, Reuben Toli; Kozone, Ikuko; Shin-ya, Kazuo; Kumazawa, Shigenori

    2012-11-28

    Three new prenylated flavonoids, namely, solophenols B (1), C (2), and D (3), as well as a new prenylated stilbene, solomonin (4), were isolated from propolis collected from the Solomon Islands. In addition, 17 known compounds were identified. The structures of the new compounds were determined by a combination of methods, including mass spectrometry and NMR. These new compounds and several known compounds were tested for antibacterial activity against Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa. Most of them exhibited potent antibacterial activity. These findings may indicate that propolis from the Solomon Islands has potential applications as an ingredient in food additives or pharmaceuticals. PMID:23067056

  3. Solophenols B-D and solomonin: new prenylated polyphenols isolated from propolis collected from the Solomon Islands and their antibacterial activity.

    PubMed

    Inui, Saori; Hosoya, Takahiro; Shimamura, Yuko; Masuda, Shuichi; Ogawa, Takeshi; Kobayashi, Hirokazu; Shirafuji, Kenichi; Moli, Reuben Toli; Kozone, Ikuko; Shin-ya, Kazuo; Kumazawa, Shigenori

    2012-11-28

    Three new prenylated flavonoids, namely, solophenols B (1), C (2), and D (3), as well as a new prenylated stilbene, solomonin (4), were isolated from propolis collected from the Solomon Islands. In addition, 17 known compounds were identified. The structures of the new compounds were determined by a combination of methods, including mass spectrometry and NMR. These new compounds and several known compounds were tested for antibacterial activity against Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa. Most of them exhibited potent antibacterial activity. These findings may indicate that propolis from the Solomon Islands has potential applications as an ingredient in food additives or pharmaceuticals.

  4. Volcano growth and evolution of the island of Hawaii

    USGS Publications Warehouse

    Moore, J.G.; Clague, D.A.

    1992-01-01

    The seven volcanoes comprising the island of Hawaii and its submarine base are, in order of growth, Mahukona, Kohala, Mauna Kea, Hualalai, Mauna Loa, Kilauea, and Loihi. The first four have completed their shield-building stage, and the timing of this event can be determined from the depth of the slope break associated with the end of shield building, calibrated using the ages and depths of a series of dated submerged coral reefs off northwest Hawaii. On each volcano, the transition from eruption of tholeiitic to alkalic lava occurs near the end of shield building. The rate of southeastern progression of the end of shield building in the interval from Haleakala to Hualalai is about 13 cm/yr. Based on this rate and an average spacing of volcanoes on each loci line of 40-60km, the volcanoes required about 600 thousand years to grow from the ocean floor to the time of the end of shield building. They arrive at the ocean surface about midway through this period. -from Authors

  5. A Bayesian inversion for slip distribution of 1 Apr 2007 Mw8.1 Solomon Islands Earthquake

    NASA Astrophysics Data System (ADS)

    Chen, T.; Luo, H.

    2013-12-01

    On 1 Apr 2007 the megathrust Mw8.1 Solomon Islands earthquake occurred in the southeast pacific along the New Britain subduction zone. 102 vertical displacement measurements over the southeastern end of the rupture zone from two field surveys after this event provide a unique constraint for slip distribution inversion. In conventional inversion method (such as bounded variable least squares) the smoothing parameter that determines the relative weight placed on fitting the data versus smoothing the slip distribution is often subjectively selected at the bend of the trade-off curve. Here a fully probabilistic inversion method[Fukuda,2008] is applied to estimate distributed slip and smoothing parameter objectively. The joint posterior probability density function of distributed slip and the smoothing parameter is formulated under a Bayesian framework and sampled with Markov chain Monte Carlo method. We estimate the spatial distribution of dip slip associated with the 1 Apr 2007 Solomon Islands earthquake with this method. Early results show a shallower dip angle than previous study and highly variable dip slip both along-strike and down-dip.

  6. Evolution of a Quaternary peralkaline volcano: Mayor Island, New Zealand

    USGS Publications Warehouse

    Houghton, B.F.; Weaver, S.D.; Wilson, C.J.N.; Lanphere, M.A.

    1992-01-01

    Mayor Island is a Holocene pantelleritic volcano showing a wide range of dispersive power and eruptive intensity despite a very limited range in magma composition of only 2% SiO2. The primary controls on this range appear to have been the magmatic gas content on eruption and a varying involvement of basaltic magma, rather than major-element chemistry of the rhyolites. The ca. 130 ka subaerial history of the volcano contains portions of three geochemical cycles with abrupt changes in trace-element chemistry following episodes of caldera collapse. The uniform major-element chemistry of the magma may relate to a fine balance between rates of eruption and supply and the higher density of the more evolved (Ferich) magmas which could be tapped only after caldera-forming events had removed significant volumes of less evolved but lighter magma. ?? 1992.

  7. Replicated Stalagmite Records of Rainfall Variability in the Solomon Islands since the Little Ice Age

    NASA Astrophysics Data System (ADS)

    Maupin, C. R.; Partin, J. W.; Quinn, T. M.; Shen, C.; Banner, J. L.; lin, K.; Taylor, F. W.; Sinclair, D.

    2011-12-01

    The tropical west Pacific warm pool (WPWP) and south Pacific convergence zone (SPCZ) play integral roles in global climate variability. Convection over the WPWP is a source of latent heat and moisture to extratropical latitudes and, in the region of the SPCZ, forms a center of action for the rising component of the zonal Pacific Walker circulation. The nature of pre-instrumental, and therefore pre-industrial, variability of convection associated with the WPWP since the Little Ice Age (LIA) is known only from sparse and spatially disparate records. As a result, it is difficult to form a robust framework on which to base estimates of future variability of zonal atmospheric circulation within the region, an important prospect given predicted weakening in the Pacific Walker circulation under global warming conditions. Here we present absolutely dated, subannually resolved, partially replicated oxygen isotope records, spanning 1420-2010 CE, from two fast growing (~2 mm yr-1) calcite speleothems from a cave in northern Guadalcanal, Solomon Islands (9.5° S, 160° E). Guadalcanal is located both within the WPWP and under the zonally oriented portion of the SPCZ. A strong degree of reproducibility between the two stalagmite δ18O time series, within dating uncertainties, favors the interpretation that the stalagmite δ18O variability is a reflection of climatic conditions over the cave, however we continue to assess the possibility of influence by any potential non-climatic processes. We assert that speleothem δ18O variability reflects changes in rainfall based on the isotope "amount effect" observed in the tropics. We find rainfall here has varied considerably on decadal to multidecadal timescales since the LIA and hypothesize a relationship between this variability and variability in the strength of shallow Pacific meridional overturning circulation (PMOC). Changes in the PMOC are thought to be responsible for decadal variability in central and eastern equatorial

  8. Operational research to inform a sub-national surveillance intervention for malaria elimination in Solomon Islands

    PubMed Central

    2012-01-01

    Background Successful reduction of malaria transmission to very low levels has made Isabel Province, Solomon Islands, a target for early elimination by 2014. High malaria transmission in neighbouring provinces and the potential for local asymptomatic infections to cause malaria resurgence highlights the need for sub-national tailoring of surveillance interventions. This study contributes to a situational analysis of malaria in Isabel Province to inform an appropriate surveillance intervention. Methods A mixed method study was carried out in Isabel Province in late 2009 and early 2010. The quantitative component was a population-based prevalence survey of 8,554 people from 129 villages, which were selected using a spatially stratified sampling approach to achieve uniform geographical coverage of populated areas. Diagnosis was initially based on Giemsa-stained blood slides followed by molecular analysis using polymerase chain reaction (PCR). Local perceptions and practices related to management of fever and treatment-seeking that would impact a surveillance intervention were also explored using qualitative research methods. Results Approximately 33% (8,554/26,221) of the population of Isabel Province participated in the survey. Only one subject was found to be infected with Plasmodium falciparum (Pf) (96 parasites/μL) using Giemsa-stained blood films, giving a prevalence of 0.01%. PCR analysis detected a further 13 cases, giving an estimated malaria prevalence of 0.51%. There was a wide geographical distribution of infected subjects. None reported having travelled outside Isabel Province in the previous three months suggesting low-level indigenous malaria transmission. The qualitative findings provide warning signs that the current community vigilance approach to surveillance will not be sufficient to achieve elimination. In addition, fever severity is being used by individuals as an indicator for malaria and a trigger for timely treatment-seeking and case reporting

  9. Deformation Associated With the M8.1 April 1, 2007 Solomon Islands Earthquake Observed With InSAR

    NASA Astrophysics Data System (ADS)

    Amelung, F.; Baker, S.

    2008-05-01

    On April 1, 2007, an Mw 8.1 earthquake occurred in the Solomon Islands located in the southwest Pacific. The earthquake resulted in considerable ground displacement and generated a tsunami that caused further damage on the island communities. Phased-Array L-band Synthetic Aperture Radar (PALSAR) data onboard the Japan Aerospace Exploration Agency (JAXA) Advance Land Observation Satellite (ALOS) was used to detect the co- seismic deformation associated with the earthquake. Interferometric synthetic aperture radar (InSAR) analysis of images acquired before and after the earthquake provided measurements of the spatial extent and magnitude of deformation. To gain a better understanding of the fault geometry and earthquake parameters, we generated fault models using inverse modeling of the observed interferograms.

  10. The recent seismo-volcanic activity at Deception Island volcano

    NASA Astrophysics Data System (ADS)

    Ibáñez, Jesús M.; Almendros, Javier; Carmona, Enrique; Martínez-Arévalo, Carmen; Abril, Miguel

    2003-06-01

    This paper reviews the recent seismic studies carried out at Deception Island, South Shetland Islands, Antarctica, which was monitored by the Argentinean and Spanish Antarctic Programs since 1986. Several types of seismic network have been deployed temporarily during each Antarctic summer. These networks have consisted of a variety of instruments, including radio-telemetered stations, autonomous digital seismic stations, broadband seismometers, and seismic arrays. We have identified two main types of seismic signals generated by the volcano, namely pure seismo-volcanic signals, such as volcanic tremor and long-period (LP) events, and volcano-tectonic (VT) earthquakes. Their temporal distributions are far from homogeneous. Volcanic tremors and LP events usually occur in seismic swarms lasting from a few hours to some days. The number of LP events in these swarms is highly variable, from a background level of less than 30/day to a peak activity of about 100 events/h. The occurrence of VT earthquakes is even more irregular. Most VT earthquakes at Deception Island have been recorded during two intense seismic crises, in 1992 and 1999, respectively. Some of these VT earthquakes were large enough to be felt by researchers working on the island. Analyses of both types of seismic events have allowed us to derive source locations, establish seismic source models, analyze seismic attenuation, calculate the energy and stress drop of the seismic sources, and relate the occurrence of seismicity to the volcanic activity. Pure seismo-volcanic signals are modelled as the consequence of hydrothermal interactions between a shallow aquifer and deeper hot materials, resulting in the resonance of fluid-filled fractures. VT earthquakes constitute the brittle response to changes in the distribution of stress in the volcanic edifice. The two VT seismic series are probably related to uplift episodes due to deep injections of magma that did not reach the surface. This evidence, however

  11. Highly divergent molecular variants of human T-lymphotropic virus type I from isolated populations in Papua New Guinea and the Solomon Islands.

    PubMed Central

    Gessian, A; Yanagihara, R; Franchini, G; Garruto, R M; Jenkins, C L; Ajdukiewicz, A B; Gallo, R C; Gajdusek, D C

    1991-01-01

    To determine the molecular genetic relationship between Melanesian strains of human T-lymphotropic virus type I (HTLV-I) and cosmopolitan prototype HTLV-I, we amplified by PCR, then cloned, and sequenced a 522-base-pair region of the HTLV-I env gene in DNA extracted from uncultured (fresh) and cultured peripheral blood mononuclear cells obtained from six seropositive Melanesian Papua New Guineans and Solomon Islanders, including a Solomon Islander with HTLV-I myeloneuropathy. Unlike isolates of HTLV-I from Japan, the West Indies, the Americas, and Africa, which share greater than or equal to 97% sequence homology, the Melanesian strains of HTLV-I were only 91.8%-92.5% identical with a prototype Japanese HTLV-IATK-1. The nucleotide sequence of proviral DNA from the Solomon Islander with HTLV-I myeloneuropathy also diverged markedly from that of HTLV-I isolated from Japanese patients with HTLV-I-associated myelopathy and from Jamaican patients with tropical spastic paraparesis, suggesting that these variant viruses are capable of causing disease. The HTLV-I variants from Papua New Guineans, in turn, differed by nearly 4% from the Melanesian variants from Solomon Islanders, indicating the existence of another HTLV-I quasi-species. By contrast, HTLV-I strains from two residents of Bellona Island, a Polynesian Outlier within the Solomon Islands, were closely related to cosmopolitan prototype HTLV-I (greater than or equal to 97% sequence identity), suggesting recent introduction, possibly during this century. These findings are consistent with a proto-Melanesian HTLV-I strain of archaic presence, which evolved independently of contemporary cosmopolitan strains, and pose new questions about the origin and global dissemination of HTLV-I. Images PMID:1881912

  12. Growth and collapse of the Reunion Island volcanoes

    NASA Astrophysics Data System (ADS)

    Oehler, Jean-François; Lénat, Jean-François; Labazuy, Philippe

    2008-04-01

    This work presents the first exhaustive study of the entire surface of the Reunion Island volcanic system. The focus is on the submarine part, for which a compilation of all multibeam data collected during the last 20 years has been made. Different types of submarine features have been identified: a coastal shelf, debris avalanches and sedimentary deposits, erosion canyons, volcanic constructions near the coast, and seamounts offshore. Criteria have been defined to differentiate the types of surfaces and to establish their relative chronology where possible. Debris avalanche deposits are by far the most extensive and voluminous formations in the submarine domain. They have built four huge Submarine Bulges to the east, north, west, and south of the island. They form fans 20-30 km wide at the coastline and 100-150 km wide at their ends, 70-80 km offshore. They were built gradually by the superimposition and/or juxtaposition of products moved during landslide episodes, involving up to several hundred cubic kilometers of material. About 50 individual events deposits can be recognized at the surface. The landslides have recurrently dismantled Piton des Neiges, Les Alizés, and Piton de La Fournaise volcanoes since 2 Ma. About one third are interpreted as secondary landslides, affecting previously emplaced debris avalanche deposits. On land, landslide deposits are observed in the extensively eroded central area of Piton des Neiges and in its coastal areas. Analysis of the present-day topography and of geology allows us to identify presumed faults and scars of previous large landslides. The Submarine Bulges are dissected and bound by canyons up to 200 m deep and 40 km long, filled with coarse-grained sediments, and generally connected to streams onshore. A large zone of sedimentary accumulation exists to the north-east of the island. It covers a zone 20 km in width, extending up to 15 km offshore. Volcanic constructions are observed near the coast on both Piton des Neiges

  13. Crustal Deformation Caused by an M8.1 Earthquake in the Solomon Islands, Detected by ALOS/PALSAR

    NASA Astrophysics Data System (ADS)

    Miyagi, Y.; Ozawa, T.; Shimada, M.

    2009-12-01

    On April 1, 2007 (UTC), a large Mw 8.1 interplate earthquake occurred in the Solomon Islands subduction zone where Pacific, Australian, Solomon Sea, and Woodlark Plates produce complicated tectonics. This earthquake was accompanied by a large tsunami and caused considerable damage in the epicentral area. The Japan Aerospace Exploration Agency (JAXA) performed emergency observations using the Advanced Land Observing Satellite (ALOS). A remote-sensing technique has the advantage of being able to observe and monitor a disaster in a remote location like the Solomon Islands that is difficult to access and receives few geophysical observations. Especially the Phased Array type L-band Synthetic Aperture Rader (PALSAR) can observe the target and get high coherence even under cloudy conditions in heavily-vegetated tropical region. We applied Differential Interferometric SAR (DInSAR) technique using data from the PALSAR installed on ALOS, and detected significant crustal deformation over wide area associated with the earthquake. Then we inverted the geodetic information from DInSAR result jointly with the field investigation data (Tomita et al., 2008), and estimated a slip distribution on the inferred seismic fault (Miyagi et al., 2009). The modeling result shows large slip areas around the hypocenter and the centroid, and the estimated slip pattern was corresponding to those deduced from teleseismic data (e.g. Yagi, 2007). It can be interpreted that the large slip area around the centroid is consistent with a strong coupling area due to a subduction of the plate boundary between the Woodlark and Australian plates, and that the small slip area is consistent with the weak coupling area under the Simbo Island caused by thermal activities related to volcanic activity of Simbo Island. The 2007 earthquake occurred in the area where has occurred no M7- or larger-sized earthquake since 1970. Although a part of the seismic gap was filled in the 2007 events, small seismic gap

  14. Perspective View of Okmok Volcano, Aleutian Islands, Alaska (#1)

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This perspective view shows the caldera of the Okmok volcano in Alaska's Aleutian Islands.

    The shaded relief was generated from and draped over an Airsar-derived digital elevation mosaic.

    Airsar collected the Alaska data as part of its PacRim 2000 Mission, which took the instrument to French Polynesia, American and Western Samoa, Fiji, New Zealand, Australia, New Guinea, Indonesia, Malaysia, Cambodia, Philippines, Taiwan, South Korea, Japan, Northern Marianas, Guam, Palau, Hawaii and Alaska. Airsar, part of NASA's Airborne Science Program, is managed for NASA's Earth Science Enterprise by JPL. JPL is a division of the California Institute of Technology in Pasadena.

  15. Perspective View of Okmok Volcano, Aleutian Islands, Alaska (#2)

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This perspective view shows the caldera of the Okmok volcano in Alaska's Aleutian Islands.

    The shaded relief was generated from and draped over an Airsar-derived digital elevation mosaic.

    Airsar collected the Alaska data as part of its PacRim 2000 Mission, which took the instrument to French Polynesia, American and Western Samoa, Fiji, New Zealand, Australia, New Guinea, Indonesia, Malaysia, Cambodia, Philippines, Taiwan, South Korea, Japan, Northern Marianas, Guam, Palau, Hawaii and Alaska. Airsar, part of NASA's Airborne Science Program, is managed for NASA's Earth Science Enterprise by JPL. JPL is a division of the California Institute of Technology in Pasadena.

  16. Agroforestry In-Service Training. A Training Aid for Asia & the Pacific Islands (Honiara, Solomon Islands, South Pacific, October 23-29, 1983). Training for Development. Peace Corps Information Collection & Exchange Training Manual No. T-16.

    ERIC Educational Resources Information Center

    Fillion, Jacob; Weeks, Julius

    The Forestry/Natural Resources Sector in the Office of Training and Program Support of the Peace Corps conducted an agroforestry inservice training workshop in Honiara, Solomon Islands, in 1983. Participants included Peace Corps volunteers and their host country national counterparts from six countries of the Pacific Islands and Asia (Western…

  17. Comparison of Holocene With Coseismic Vertical Deformation Accompanying the Great 1 April 2007 Solomon Islands Megathrust Rupture

    NASA Astrophysics Data System (ADS)

    Taylor, F. W.; Briggs, R.; Frohlich, C.; Papabatu, A. K.; Billy, D.; Brown, A.; Meltzner, A. J.

    2007-12-01

    The 1 April 2007 Mw 8.1 earthquake in the western Solomons arc is the first major seismic rupture of this segment of plate boundary in historical times. A remarkable property of this region is the existence of coral- fringed islands located in a belt from ~90 km to as close as ~5 km from the trench. This setting provides a unique opportunity in which to measure forearc vertical movements using corals and other data to reveal relationships among coseismic vertical displacement, extremely rapid uplift of the outer forearc, and slower uplift of the main volcanic arc. The location of maximum coseismic uplift along a trench-parallel belt adjacent to the trench is consistent with the trench-parallel belt of maximum Holocene uplift rates. However, islands along the main volcanic arc lie in the swath of coseismic subsidence located arcward and parallel to the uplift zone. These islands typically have mean Holocene uplift rates up to ~1mm/yr. Thus, coseismic uplift correlates with rapid outer forearc Holocene uplift, but coseismic subsidence occurred throughout the more slowly uplifting volcanic arc. Using these observations, we can deconvolve and isolate the components of co- seismic, interseismic, and net vertical deformation and seek to address the underlying mechanisms. Interpretation is complicated by the late Quaternary history that includes subsidence of both the inner and outer arc islands prior to initiation of the ongoing net uplift since ~50 ka.

  18. Control of scabies, skin sores and haematuria in children in the Solomon Islands: another role for ivermectin.

    PubMed Central

    Lawrence, Gregor; Leafasia, Judson; Sheridan, John; Hills, Susan; Wate, Janet; Wate, Christine; Montgomery, Janet; Pandeya, Nirmala; Purdie, David

    2005-01-01

    OBJECTIVE: To assess the effects of a 3-year programme aimed at controlling scabies on five small lagoon islands in the Solomon Islands by monitoring scabies, skin sores, streptococcal skin contamination, serology and haematuria in the island children. METHODS: Control was achieved by treating almost all residents of each island once or twice within 2 weeks with ivermectin (160-250 microg/kg), except for children who weighed less than 15 kg and pregnant women, for whom 5% permethrin cream was used. Reintroduction of scabies was controlled by treating returning residents and visitors, whether or not they had evident scabies. FINDINGS: Prevalence of scabies dropped from 25% to less than 1% (P < 0.001); prevalence of sores from 40% to 21% (P < 0.001); streptococcal contamination of the fingers in those with and without sores decreased significantly (P = 0.02 and 0.047, respectively) and anti-DNase B levels decreased (P = 0.002). Both the proportion of children with haematuria and its mean level fell (P = 0.002 and P < 0.001, respectively). No adverse effects of the treatments were seen. CONCLUSION: The results show that ivermectin is an effective and practical agent in the control of scabies and that control reduces the occurrence of streptococcal skin disease and possible signs of renal damage in children. Integrating community-based control of scabies and streptococcal skin disease with planned programmes for controlling filariasis and intestinal nematodes could be both practical and produce great health benefits. PMID:15682247

  19. Jets in the Coral Sea: observation between New Caledonia, Vanuatu and the Solomon Islands during the SECALIS cruises.

    NASA Astrophysics Data System (ADS)

    Ganachaud, A.; Gourdeau, L.; Kestenare, E.

    2006-12-01

    The CLIVAR program and many recent publications underline the importance of the oceanic connection between the south subtropical Pacific, where mode waters acquire their properties from the contact with the atmosphere, and the equator, where those same waters emerge after a 10 to 15-year travel-time below the surface. Recent field work and modeling studies have revealed a complex pathway taken by those waters as they cross the Southwest Pacific region. Planetary dynamics and numerous topographic obstacles create oceanic jets, strong zonal currents that cross the Coral Sea before reaching the Australian coast western boundary current system and splitting with an important amount of water heading north towards the Equatorial Undercurrent and finally reaching the equatorial upwelling region. The observations made during SECALIS cruises (2003-2006) between New Caledonia, the Solomon Islands and Vanuatu, are presented. The CTD- ADCP sections revealed the existence of narrow jets at the northern and southern tips of Vanuatu and New Caledonia.

  20. Permethrin-impregnated bednets are more effective than DDT house-spraying to control malaria in Solomon Islands.

    PubMed

    Kere, N K; Arabola, A; Bakote'e, B; Qalo, O; Burkot, T R; Webber, R H; Southgate, B A

    1996-04-01

    A field trial compared DDT house-spraying with permethrin-impregnated bednets for malaria control in Solomon Islands from 1987 to 1991. Mortality-rates of malaria vector Anopheles farauti in exit window traps were 11.6% from an untreated hut, 10.1% from a hut sprayed with DDT 2 g/m2, and 98% of those from a hut in which the occupants used bednets treated with permethrin 0.5 g/m2. Since bioassays of the DDT-sprayed walls (15 min exposure in W.H.O. standard test cones) gave 77% mortality of An.farauti, it was concluded that the insignificant impact of DDT could be explained by the exophilic behaviour of endophagic vectors, whereas the greater impact of permethrin was attributed to the more effective exposure of An.farauti females to the impregnated bednets-attracted by the occupants. The parous rate was higher indoors, except in the area with permethrin-impregnated bednets. It was therefore concluded that permethrin-impregnated bednets reduced the mean longevity of An.farauti and hence its vectorial capacity. The circumsporozoite (CS) antigen positivity rate of An.farauti in the DDT area was 0.18% outdoors, significantly less than 1.42% indoors. In the comparison area CS rates were 0.65% outdoors and 0.75% indoors. CS antigen was not detected in An.farauti from the bednet area, indicating the apparent prevention of malaria transmission. As DDT spraying was so much less effective, it was discontinued in 1993 and permethrin-impregnated bednets are now the principal malaria control method in Solomon Islands. PMID:8744706

  1. Arc lavas on both sides of a trench: Slab window effects at the Solomon Islands triple junction, SW Pacific

    NASA Astrophysics Data System (ADS)

    Chadwick, John; Perfit, Michael; McInnes, Brent; Kamenov, George; Plank, Terry; Jonasson, Ian; Chadwick, Claire

    2009-03-01

    The Woodlark Spreading Center (WSC) is subducted at the San Cristobal trench, forming a triple junction at the New Georgia Group (NGG) arc in the Solomon Islands. WSC lavas are N-MORB at > 100 km from the trench, but with decreasing distance they have increasingly arc-like Sr-Nd-Pb isotopic ratios, enrichments in Rb > K > Pb > Sr, and depletions in HFSE and Y. Within 50 km of the trench on the Simbo and Ghizo Ridges, many recovered samples are island arc tholeiites to medium-K calc-alkaline andesites and dacites, and many have the same or similar major and trace element and isotopic characteristics as true arc lavas in the NGG on the other side of the trench. Previous investigations have concluded that these WSC lavas are the result of relic back arc mantle enrichments resulting from subduction of the Pacific plate prior to the late Miocene at the North Solomon trench, > 200 km to the north. However, the high-silica WSC lavas are more arc-like than those recovered from other distal back arcs, and are more voluminous, forming large submarine ridges and stratovolcanoes. We suggest that true arc mantle migrates across the plate boundary from the adjacent NGG arc through slab windows created by the subduction of the WSC. This leads to variable mixing between NGG arc and WSC N-MORB end-members, forming the transitional lavas recovered from the WSC. Lavas with similar arc-like characteristics have previously been recovered on the Chile Rise near where it is subducted at the Chile Trench, raising the possibility that such mantle transfer is a common phenomenon where active spreading centers are subducted. The presence of slab windows may also be responsible for the unusual forearc volcanism in the NGG, and melting of slab window margins may account for the presence of high-silica adakite-like lavas on the WSC.

  2. The Effect of the Great Barrier Reef on the Propagation of the 2007 Solomon Islands Tsunami Recorded in Northeastern Australia

    NASA Astrophysics Data System (ADS)

    Baba, Toshitaka; Mleczko, Richard; Burbidge, David; Cummins, Phil R.; Thio, Hong Kie

    2008-12-01

    The effect of offshore coral reefs on the impact from a tsunami remains controversial. For example, field surveys after the 2004 Indian Ocean tsunami indicate that the energy of the tsunami was reduced by natural coral reef barriers in Sri Lanka, but there was no indication that coral reefs off Banda Aceh, Indonesia had any effect on the tsunami. In this paper, we investigate whether the Great Barrier Reef (GBR) offshore Queensland, Australia, may have weakened the tsunami impact from the 2007 Solomon Islands earthquake. The fault slip distribution of the 2007 Solomon Islands earthquake was firstly obtained by teleseismic inversion. The tsunami was then propagated to shallow water just offshore the coast by solving the linear shallow water equations using a staggered grid finite-difference method. We used a relatively high resolution (approximately 250 m) bathymetric grid for the region just off the coast containing the reef. The tsunami waveforms recorded at tide gauge stations along the Australian coast were then compared to the results from the tsunami simulation when using both the realistic 250 m resolution bathymetry and with two grids having fictitious bathymetry: One in which the the GBR has been replaced by a smooth interpolation from depths outside the GBR to the coast (the “No GBR” grid), and one in which the GBR has been replaced by a flat plane at a depth equal to the mean water depth of the GBR (the “Average GBR” grid). From the comparison between the synthetic waveforms both with and without the Great Barrier Reef, we found that the Great Barrier Reef significantly weakened the tsunami impact. According to our model, the coral reefs delayed the tsunami arrival time by 5-10 minutes, decreased the amplitude of the first tsunami pulse to half or less, and lengthened the period of the tsunami.

  3. A Newly Recognized Shield Volcano Southwest of Oahu Island, Hawaii

    NASA Astrophysics Data System (ADS)

    Takahashi, E.; Moore, J. G.; Yokose, H.; Clague, D. A.; Nakagawa, M.; Kani, T.; Coombs, M.; Moore, G.; Harada, Y.; Kunikiyo, T.; Robinson, J.

    2001-12-01

    alkalic basalt composition. Dive K206 (20\\deg39.0'N, 158\\deg47.5'W) on one of the flat top cones imaged and sampled dense aphyric pillow lava (also with thick Mn-coating) cascading down the steep flank. Preliminary data collected from the recently completed cruise indicates that this newly mapped submarine Hawaiian shield volcano (2000-4000 km3) is similar in age to those on Oahu island (Waianae and Koolau), and apparently grew during several stages of magmatic activity.

  4. Preliminary Seismic Tomography of Deception Island Volcano, South Shetland Islands (Antarctica)

    NASA Astrophysics Data System (ADS)

    Zandomeneghi, D.; Barclay, A. H.; Ben Zvi, T.; Wilcock, W.; Ibáñez, J. M.; Almendros, J.

    2005-12-01

    Deception Island, 62°59' S, 60°41' W, is an active volcano located in Bransfield Strait between the Antarctic Peninsula and the main South Shetland Islands. The volcano has a basal diameter of ~30 km and rises ~1500 m from the seafloor to a maximum height of over 500 m above sea level. The 15-km-diameter emerged island is horseshoe-shaped with a flooded inner bay that is accessible to the ocean through a 500-m-wide passage. The island is composed of volcanic rocks which date from <0.75 Ma to historical eruptions (1842, 1967, 1969 and 1970). The volcano lies in a complicated tectonic setting on the South Shetland block and its origin is poorly understood. The island is situated north of the main axis of the Bransfield Strait, a tensional structure interpreted as an active back-arc basin, but its geochemistry and seismic activity appear to be influenced by arc volcanism that once strongly affected the South Shetland Islands.In January 2005 an extensive seismic survey took place in and around the island, with the participation of researchers from Spain, the United States, Italy, Ireland, Mexico, Argentina and Germany. The main objective of the experiment was to collect a high quality data set that could be used to obtain two and three-dimensional P-wave tomographic images of the volcano. A total of 119 land seismic stations and 14 ocean bottom seismometers were deployed for two rounds of shooting and recorded more than 5000 airgun shots that were distributed within the caldera and around the island. The initial dataset used for the three-dimensional seismic tomography comprises more than 90000 P-wave travel times that were determined using both automatic and manual first-arrival picking procedures. The inversion code makes use of accurate ray tracing procedure and comprehensive topography's information.A preliminary three-dimensional P-wave inversion of the automatically-picked travel times resolves structure down to 4 km depth. The tomographic image is

  5. Crustal deformation associated with an M8.1 earthquake in the Solomon Islands, detected by ALOS/PALSAR

    NASA Astrophysics Data System (ADS)

    Miyagi, Yousuke; Ozawa, Taku; Shimada, Masanobu

    2009-10-01

    On April 1, 2007 (UTC), a large Mw 8.1 interplate earthquake struck the Solomon Islands subduction zone where complicated tectonics result from the subduction of four plates. Extensive ground movements and a large tsunami occurred in the epicentral area causing severe damage over a wide area. Using ALOS/PALSAR data and the DInSAR technique, we detected crustal deformation exceeding 2 m in islands close to the epicenter. A slip distribution of the inferred seismic fault was estimated using geodetic information derived from DInSAR processing and field investigations. The result indicates large slip areas around the hypocenter and the centroid. It is possible that the largest slip area is related to subduction of the plate boundary between the Woodlark and Australian plates. A small slip area between those large slip areas may indicate weak coupling due to thermal activity related to volcanic activity on Simbo Island. The 2007 earthquake struck an area where large earthquake has not occurred since 1970. Most of this seismic gap was filled by the 2007 events, however a small seismic gap still remains in the southeastern region of the 2007 earthquake.

  6. Genetic diversity in two sibling species of the Anopheles punctulatus group of mosquitoes on Guadalcanal in the Solomon Islands

    PubMed Central

    2008-01-01

    Background The mosquito Anopheles irenicus, a member of the Anopheles punctulatus group, is geographically restricted to Guadalcanal in the Solomon Islands. It shows remarkable morphological similarities to one of its sibling species, An. farauti sensu stricto (An. farauti s.s.), but is dissimilar in host and habitat preferences. To infer the genetic variations between these two species, we have analyzed mitochondrial cytochrome oxidase subunit II (COII) and nuclear ribosomal internal transcribed spacer 2 (ITS2) sequences from Guadalcanal and from one of its nearest neighbours, Malaita, in the Solomon Islands. Results An. farauti s.s. was collected mostly from brackish water and by the human bait method on both islands, whereas An. irenicus was only collected from fresh water bodies on Guadalcanal Island. An. irenicus is distributed evenly with An. farauti s.s. (ΦSC = 0.033, 0.38%) and its range overlaps in three of the seven sampling sites. However, there is a significant population genetic structure between the species (ΦCT = 0.863, P < 0.01; ΦST = 0.865, P < 0.01 and FST = 0.878, P < 0.01). Phylogenetic analyses suggest that An. irenicus is a monophyletic species, not a hybrid, and is closely related to the An. farauti s.s. on Guadalcanal. The time estimator suggests that An. irenicus diverged from the ancestral An. farauti s.s. on Guadalcanal within 29,000 years before present (BP). An. farauti s.s. expanded much earlier on Malaita (texp = 24,600 BP) than the populations on Guadalcanal (texp = 16,800 BP for An. farauti s.s. and 14,000 BP for An. irenicus). Conclusion These findings suggest that An. irenicus and An. farauti s.s. are monophyletic sister species living in sympatry, and their populations on Guadalcanal have recently expanded. Consequently, the findings further suggest that An. irenicus diverged from the ancestral An. farauti s.s. on Guadalcanal. PMID:19025663

  7. Remote sensing for active volcano monitoring in Barren Island, India

    SciTech Connect

    Bhattacharya, A.; Reddy, C.S.S.; Srivastav, S.K. )

    1993-08-01

    The Barren Island Volcano, situated in the Andaman Sea of the Bay of Bengal, erupted recently (March, 1991) after a prolonged period of quiescence of about 188 years. This resumed activity coincides with similar outbreaks in the Philippines and Japan, which are located in an identical tectonic environment. This study addresses (1) remote sensing temporal monitoring of the volcanic activity, (2) detecting hot lava and measuring its pixel-integrated and subpixel temperatures, and (3) the importance of SWIR bands for high temperature volcanic feature detection. Seven sets of TM data acquired continuously from 3 March 1991 to 8 July 1991 have been analyzed. It is concluded that detectable pre-eruption warming took place around 25 March 1991 and volcanic activity started on 1 April 1991. It is observed that high temperature features, such as an erupting volcano, can register emitted thermal radiance in SWIR bands. Calculation of pixel-integrated and sub-pixel temperatures related to volcanic vents has been made, using the dual-band method. 6 refs.

  8. Volcano-Hydrothermal Systems of the Central and Northern Kuril Island Arc - a Review

    NASA Astrophysics Data System (ADS)

    Kalacheva, E.; Taran, Y.; Voloshina, E.; Ptashinsky, L.

    2015-12-01

    More than 20 active volcanoes with historical eruptions are known on 17 islands composing the Central and Northern part of the Kurilian Arc. Six islands - Paramushir, Shiashkotan, Rasshua, Ushishir, Ketoy and Simushir - are characterized by hydrothermal activity, complementary to the fumarolic activity in their craters. There are several types of volcano-hydrothermal systems on the islands. At Paramushir, Shiashkotan and Ketoy the thermal manifestations are acidic to ultra-acidic water discharges associated with hydrothermal aquifers inside volcano edifices and formed as the result of the absorption of magmatic gases by ground waters. A closest known analogue of such activity is Satsuma-Iwojima volcano-island at the Ryukyu Arc. Another type of hydrothermal activity are wide spread coastal hot springs (Shiashkotan, Rasshua), situated as a rule within tide zones and formed by mixing of the heated seawater with cold groundwater or, in opposite, by mixing of the steam- or conductively heated groundwater with seawater. This type of thermal manifestation is similar to that reported for other volcanic islands of the world (Satsuma Iwojima, Monserrat, Ischia, Socorro). Ushishir volcano-hydrothermal system is formed by the absorption of magmatic gases by seawater. Only Ketoy Island hosts a permanent acidic crater lake. At Ebeko volcano (Paramushir) rapidly disappearing small acidic lakes (formed after phreatic eruptions) have been reported. The main hydrothermal manifestation of Simushir is the Zavaritsky caldera lake with numerous coastal thermal springs and weak steam vents. The last time measured temperatures of fumaroles at the islands are: >500ºC at Pallas Peak (Ketoy), 480ºC at Kuntamintar volcano (Shiashkotan), variable and fast changing temperatures from 120º C to 500ºC at Ebeko volcano (Paramushir), 150ºC in the Rasshua crater, and > 300ºC in the Chirpoy crater (Black Brothers islands). The magmatic and rock-forming solute output by the Kurilian volcano

  9. The 2014 Submarine Eruption of Ahyi Volcano, Northern Mariana Islands

    NASA Astrophysics Data System (ADS)

    Haney, M. M.; Chadwick, W.; Merle, S. G.; Buck, N. J.; Butterfield, D. A.; Coombs, M. L.; Evers, L. G.; Heaney, K. D.; Lyons, J. J.; Searcy, C. K.; Walker, S. L.; Young, C.; Embley, R. W.

    2014-12-01

    On April 23, 2014, Ahyi Volcano, a submarine cone in the Northern Mariana Islands (NMI), ended a 13-year-long period of repose with an explosive eruption lasting over 2 weeks. The remoteness of the volcano and the presence of several seamounts in the immediate area posed a challenge for constraining the source location of the eruption. Critical to honing in on the Ahyi area quickly were quantitative error estimates provided by the CTBTO on the backazimuth of hydroacoustic arrivals observed at Wake Island (IMS station H11). T-phases registered across the NMI seismic network at the rate of approximately 10 per hour until May 8 and were observed in hindsight at seismic stations on Guam and Chichijima. After May 8, sporadic T-phases were observed until May 17. Within days of the eruption onset, reports were received from NOAA research divers of hearing explosions underwater and through the hull on the ship while working on the SE coastline of Farallon de Pajaros (Uracas), a distance of 20 km NW of Ahyi. In the same area, the NOAA crew reported sighting mats of orange-yellow bubbles on the water surface and extending up to 1 km from the shoreline. Despite these observations, satellite images showed nothing unusual throughout the eruption. During mid-May, a later cruise leg on the NOAA ship Hi'ialakai that was previously scheduled in the Ahyi area was able to collect some additional data in response to the eruption. Preliminary multibeam sonar bathymetry and water-column CTD casts were obtained at Ahyi. Comparison between 2003 and 2014 bathymetry revealed that the minimum depth had changed from 60 m in 2003 to 75 m in 2014, and a new crater ~95 m deep had formed at the summit. Extending SSE from the crater was a new scoured-out landslide chute extending downslope to a depth of at least 2300 m. Up to 125 m of material had been removed from the head of the landslide chute and downslope deposits were up to 40 m thick. Significant particle plumes were detected at all three

  10. Interseismic, coseismic, postseismic, and slow slip event deformation above a shallow subduction thrust in the western Solomon Islands

    NASA Astrophysics Data System (ADS)

    Wallace, L. M.; Taylor, F. W.; Bevis, M. G.; Phillips, D. A.; Walter, J. I.; Kendrick, E. C.; Papabatu, A. K.

    2015-12-01

    The western Solomon Islands are a remarkable natural laboratory to investigate processes occurring on the shallowest (<10 km depth) portions of the subduction interface. Islands within the New Georgia Group are located <15 km from the San Cristobal Trench, with the subduction thrust located only a few km beneath the southwest coast of islands like Rannonga and Rendova. This offers a globally unique opportunity to use GPS and other land-based methods to monitor deformation processes very close to the trench at a subduction zone. We present results from a campaign GPS network in the western Solomons that has been operated from 1996-present. The data from 1996-2002 indicate interseismic coupling on the shallow portion of the interface, at a rate of nearly 100% of the relative plate motion. Coupling does not appear to extend deeper than ~20 km depth, and the relatively shallow down-dip limit of coupling is consistent with subduction of young (<6 Ma) oceanic crust of the Woodlark Basin. We also show evidence for a slow slip event in late 2000, observed at a GPS site near Gizo that was running continuously from 1999-2002. In April 2007, an Mw 8.1 earthquake occurred on the subduction thrust beneath the network, resulting in large coseismic displacements at nearby campaign GPS sites. The earthquake caused widespread coastal uplift and subsidence in the region, as revealed by studies of coral microatolls following the earthquake (Taylor et al., 2008). We invert displacements of the GPS sites jointly with vertical displacements of coral microatolls to evaluate the coseismic slip during the earthquake. The area of the interface that underwent slip in the earthquake matches well with the region that was interseismically coupled just prior to the 2007 earthquake. The data also require large coseismic slip on the shallow interface near the trench, which likely contributed to the generation of a large, damaging tsunami following the earthquake. We also show results from a recent

  11. A qualitative study on the acceptability and preference of three types of long-lasting insecticide-treated bed nets in Solomon Islands: implications for malaria elimination

    PubMed Central

    Atkinson, Jo-An; Bobogare, Albino; Fitzgerald, Lisa; Boaz, Leonard; Appleyard, Bridget; Toaliu, Hilson; Vallely, Andrew

    2009-01-01

    Background In March 2008, the Solomon Islands and Vanuatu governments raised the goal of their National Malaria Programmes from control to elimination. Vector control measures, such as indoor residual spraying (IRS) and long-lasting insecticidal bed nets (LLINs) are key integral components of this programme. Compliance with these interventions is dependent on their acceptability and on the socio-cultural context of the local population. These factors need to be investigated locally prior to programme implementation. Method Twelve focus group discussions (FGDs) were carried out in Malaita and Temotu Provinces, Solomon Islands in 2008. These discussions explored user perceptions of acceptability and preference for three brands of long-lasting insecticide-treated bed nets (LLINs) and identified a number of barriers to their proper and consistent use. Results Mosquito nuisance and perceived threat of malaria were the main determinants of bed net use. Knowledge of malaria and the means to prevent it were not sufficient to guarantee compliance with LLIN use. Factors such as climate, work and evening social activities impact on the use of bed nets, particularly in men. LLIN acceptability plays a varying role in compliance with their use in villages involved in this study. Participants in areas of reported high and year round mosquito nuisance and perceived threat of malaria reported LLIN use regardless of any reported unfavourable characteristics. Those in areas of low or seasonal mosquito nuisance were more likely to describe the unfavourable characteristics of LLINs as reasons for their intermittent or non-compliance. The main criterion for LLIN brand acceptability was effectiveness in preventing mosquito bites and malaria. Discussions highlighted considerable confusion around LLIN care and washing which may be impacting on their effectiveness and reducing their acceptability in Solomon Islands. Conclusion Providing LLINs that are acceptable will be more important for

  12. August 2008 eruption of Kasatochi volcano, Aleutian Islands, Alaska-resetting an Island Landscape

    USGS Publications Warehouse

    Scott, W.E.; Nye, C.J.; Waythomas, C.F.; Neal, C.A.

    2010-01-01

    Kasatochi Island, the subaerial portion of a small volcano in the western Aleutian volcanic arc, erupted on 7-8 August 2008. Pyroclastic flows and surges swept the island repeatedly and buried most of it and the near-shore zone in decimeters to tens of meters of deposits. Several key seabird rookeries in taluses were rendered useless. The eruption lasted for about 24 hours and included two initial explosive pulses and pauses over a 6-hr period that produced ash-poor eruption clouds, a 10-hr period of continuous ash-rich emissions initiated by an explosive pulse and punctuated by two others, and a final 8-hr period of waning ash emissions. The deposits of the eruption include a basal muddy tephra that probably reflects initial eruptions through the shallow crater lake, a sequence of pumiceous and lithic-rich pyroclastic deposits produced by flow, surge, and fall processes during a period of energetic explosive eruption, and a fine-grained upper mantle of pyroclastic-fall and -surge deposits that probably reflects the waning eruptive stage as lake and ground water again gained access to the erupting magma. An eruption with similar impact on the island's environment had not occurred for at least several centuries. Since the 2008 eruption, the volcano has remained quiet other than emission of volcanic gases. Erosion and deposition are rapidly altering slopes and beaches. ?? 2010 Regents of the University of Colorado.

  13. Formation and Evolution of the San Cristobal Trough Transform Fault Linking the Southern Solomon Islands and Northern New Hebrides Trenches

    NASA Astrophysics Data System (ADS)

    Furlong, K. P.; Hayes, G. P.; Herman, M. W.; Benz, H.

    2014-12-01

    The San Cristobal Trough, which occupies the southern segment of the South Solomon Trench, hosts a dominantly left-lateral transform plate boundary (SCTF) linking the southern end of the Solomon Islands subduction zone (SISZ) to the northern end of the New Hebrides (Vanuatu) subduction zone (NHSZ). At its western end (SISZ), the Australia plate is torn as a result of the transition from subduction to transform motion. The southern side of the tear translates approximately 375 km along the SCTF before subducting beneath the Santa Cruz Islands at the NHSZ. Earthquakes occurring along this transform reflect the processes of plate tearing, fault zone evolution, and subsequent underthrusting and subduction of the Australia-plate-side of the transform. A knot of earthquake activity at the western end of the SCTF juxtaposes high-angle thrust faulting events with left-lateral strike slip events. These record the tearing of Australian lithosphere, as shown by a recent pair of large earthquakes in that region - a Mw 7.6 strike-slip event (12 April 2014) followed 22 hours later by a Mw 7.4 high-angle reverse faulting event (13 April 2014). Associated displacements reflect oblique tearing (northern-side down and west), allowing the Australia Plate to follow two disparate paths - subduction at the SISZ to the north and translation along the SCTF to the south. Moving eastward along the transform, the plate boundary shows three styles of earthquake activity. The main transform is dominated by shallow, E-W striking, left-lateral faulting and E-W striking thrust faults (with a north-dipping shallow fault plane) - these reflect partitioning of oblique motion along the transform between the Australia and Pacific plates. Outboard (+/- 100 km) of the plate boundary, a group of E-W striking shallow normal faulting events reflect upward bending driven by the convergent component of plate motions. Approaching the NHSZ, normal faulting earthquakes in the Australia Plate rotate clockwise

  14. Malaria elimination in Isabel Province, Solomon Islands: establishing a surveillance-response system to prevent introduction and reintroduction of malaria

    PubMed Central

    2011-01-01

    Background The Solomon Islands National Malaria Programme is currently focused on intensified control and progressive elimination. Recent control efforts in Isabel Province have reduced their malaria incidence to 2.6/1,000 population in 2009 [1] whereas most neighbouring provinces have much higher incidences. A malaria surveillance-response system that involves testing all travellers entering Isabel Province using rapid diagnostic tests (RDT) to prevent cases being imported had been proposed by local health authorities. This study provides information on the feasibility and acceptability of implementing a new approach of surveillance and response in the context of low levels of indigenous malaria transmission in Isabel Province. Methods A total of 13 focus group discussions (FGD) and 22 key informant interviews (KII) were conducted in Isabel Province, Solomon Islands. Key topics included: the travel patterns of people to, from and within Isabel Province; the acceptability, community perceptions, attitudes and suggestions towards the proposed surveillance programme; and management of suspected malaria cases. This information was triangulated with data obtained from port authorities, airlines and passenger ships travelling to and from Isabel Province in the preceding two years. Results Travel within Isabel Province and to and from other provinces is common with marked seasonality. The majority of inter-provincial travel is done on scheduled public transport; namely passenger ships and aircrafts. In Isabel Province there is a healthy community spirit as well as high concern regarding malaria and its importation and there is currently effective malaria passive case detection and management. Conducting malaria screening at ports and airports would be acceptable to the community. Conclusion A robust surveillance-response system is essential when moving towards malaria elimination. Many factors contribute positively towards the feasibility of an RDT based malaria

  15. Preliminary Geologic Map of Mount Pagan Volcano, Pagan Island, Commonwealth of the Northern Mariana Islands

    USGS Publications Warehouse

    Trusdell, Frank A.; Moore, Richard B.; Sako, Maurice K.

    2006-01-01

    Pagan Island is the subaerial portion of two adjoining Quaternary stratovolcanoes near the middle of the active Mariana Arc, [FAT1]north of Saipan. Pagan and the other volcanic islands that constitute part of the Arc form the northern half of the East Mariana Ridge[FAT2], which extends about 2-4 km above the ocean floor. The > 6-km-deep Mariana Trench adjoins the East Mariana Ridge on the east, and the Mariana Trough, partly filled with young lava flows and volcaniclastic sediment, lies on the west of the Northern Mariana Islands (East Mariana Ridge. The submarine West Mariana Ridge, Tertiary in age, bounds the western side of the Mariana Trough. The Mariana Trench and Northern Mariana Islands (East Mariana Ridge) overlie an active subduction zone where the Pacific Plate, moving northwest at about 10.3 cm/year, is passing beneath the Philippine Plate, moving west-northwest at 6.8 cm/year. Beneath the Northern Mariana Islands, earthquake hypocenters at depths of 50-250 km identify the location of the west-dipping subduction zone, which farther west becomes nearly vertical and extends to 700 km depth. During the past century, more than 40 earthquakes of magnitude 6.5-8.1 have shaken the Mariana Trench. The Mariana Islands form two sub-parallel, concentric, concave-west arcs. The southern islands comprise the outer arc and extend north from Guam to Farallon de Medinilla. They consist of Eocene to Miocene volcanic rocks and uplifted Tertiary and Quaternary limestone. The nine northern islands extend from Anatahan to Farallon de Pajaros and form part of the inner arc. The active inner arc extends south from Anatahan, where volcanoes, some of which are active, form seamounts west of the older outer arc. Other volcanic seamounts of the active arc surmount the East Mariana Ridge in the vicinity of Anatahan and Sarigan and north and south of Farallon de Pajaros. Six volcanoes (Farallon de Pajaros, Asuncion, Agrigan, Mount Pagan, Guguan, and Anatahan) in the northern islands

  16. Modeling volcano growth on the Island of Hawaii: deep-water perspectives

    USGS Publications Warehouse

    Lipman, Peter W.; Calvert, Andrew T.

    2013-01-01

    Recent ocean-bottom geophysical surveys, dredging, and dives, which complement surface data and scientific drilling at the Island of Hawaii, document that evolutionary stages during volcano growth are more diverse than previously described. Based on combining available composition, isotopic age, and geologically constrained volume data for each of the component volcanoes, this overview provides the first integrated models for overall growth of any Hawaiian island. In contrast to prior morphologic models for volcano evolution (preshield, shield, postshield), growth increasingly can be tracked by age and volume (magma supply), defining waxing alkalic, sustained tholeiitic, and waning alkalic stages. Data and estimates for individual volcanoes are used to model changing magma supply during successive compositional stages, to place limits on volcano life spans, and to interpret composite assembly of the island. Volcano volumes vary by an order of magnitude; peak magma supply also varies sizably among edifices but is challenging to quantify because of uncertainty about volcano life spans. Three alternative models are compared: (1) near-constant volcano propagation, (2) near-equal volcano durations, (3) high peak-tholeiite magma supply. These models define inconsistencies with prior geodynamic models, indicate that composite growth at Hawaii peaked ca. 800–400 ka, and demonstrate a lower current rate. Recent age determinations for Kilauea and Kohala define a volcano propagation rate of 8.6 cm/yr that yields plausible inception ages for other volcanoes of the Kea trend. In contrast, a similar propagation rate for the less-constrained Loa trend would require inception of Loihi Seamount in the future and ages that become implausibly large for the older volcanoes. An alternative rate of 10.6 cm/yr for Loa-trend volcanoes is reasonably consistent with ages and volcano spacing, but younger Loa volcanoes are offset from the Kea trend in age-distance plots. Variable magma flux

  17. Supporting Pacific Island Countries to Strengthen Their Resistance to Tobacco Industry Interference in Tobacco Control: A Case Study of Papua New Guinea and Solomon Islands

    PubMed Central

    McCool, Judith; McKenzie, Jeanie; Lyman, Annabel; Allen, Matthew

    2013-01-01

    Tobacco use is the biggest single preventable cause of non-communicable diseases (NCDs) in the Western Pacific region. Currently, 14 Pacific Island countries have ratified the WHO Framework Convention on Tobacco Control (FCTC) and, in having done so, are committed to implementing tobacco control measures aligned with the FCTC. Progressing strong and effective tobacco control legislation is essential to achieving long term gains in public health in small island countries. However, survey evidence suggests that pervasive tobacco industry interference serves to undermine tobacco control and public policy in several Pacific countries. An initiative was developed to provide dedicated, in-country technical support for developing legislation and policy to support implementation of Article 5.3 of the FCTC in the Solomon Islands and Papua New Guinea. This paper examines the factors that have assisted the two Pacific countries to make progress in implementing Article 5.3 and what this might mean for supporting progress in other Pacific settings. A document analysis was undertaken to identify the process and outcome of the intervention. Two significant outputs from the project including having identified and documented specific examples of TII and the development of draft legislation for Article 5.3 and other key resources for public servants both within and outside the health sector. Key determinants of progress included a motivated and engaged Ministry of Health, active civil society group or champion and access to media to prepare tobacco industry related material to stimulate public and policy sector debate. PMID:23924884

  18. Supporting Pacific Island countries to strengthen their resistance to tobacco industry interference in tobacco control: a case study of Papua New Guinea and Solomon Islands.

    PubMed

    McCool, Judith; McKenzie, Jeanie; Lyman, Annabel; Allen, Matthew

    2013-08-01

    Tobacco use is the biggest single preventable cause of non-communicable diseases (NCDs) in the Western Pacific region. Currently, 14 Pacific Island countries have ratified the WHO Framework Convention on Tobacco Control (FCTC) and, in having done so, are committed to implementing tobacco control measures aligned with the FCTC. Progressing strong and effective tobacco control legislation is essential to achieving long term gains in public health in small island countries. However, survey evidence suggests that pervasive tobacco industry interference serves to undermine tobacco control and public policy in several Pacific countries. An initiative was developed to provide dedicated, in-country technical support for developing legislation and policy to support implementation of Article 5.3 of the FCTC in the Solomon Islands and Papua New Guinea. This paper examines the factors that have assisted the two Pacific countries to make progress in implementing Article 5.3 and what this might mean for supporting progress in other Pacific settings. A document analysis was undertaken to identify the process and outcome of the intervention. Two significant outputs from the project including having identified and documented specific examples of TII and the development of draft legislation for Article 5.3 and other key resources for public servants both within and outside the health sector. Key determinants of progress included a motivated and engaged Ministry of Health, active civil society group or champion and access to media to prepare tobacco industry related material to stimulate public and policy sector debate. PMID:23924884

  19. Supporting Pacific Island countries to strengthen their resistance to tobacco industry interference in tobacco control: a case study of Papua New Guinea and Solomon Islands.

    PubMed

    McCool, Judith; McKenzie, Jeanie; Lyman, Annabel; Allen, Matthew

    2013-08-06

    Tobacco use is the biggest single preventable cause of non-communicable diseases (NCDs) in the Western Pacific region. Currently, 14 Pacific Island countries have ratified the WHO Framework Convention on Tobacco Control (FCTC) and, in having done so, are committed to implementing tobacco control measures aligned with the FCTC. Progressing strong and effective tobacco control legislation is essential to achieving long term gains in public health in small island countries. However, survey evidence suggests that pervasive tobacco industry interference serves to undermine tobacco control and public policy in several Pacific countries. An initiative was developed to provide dedicated, in-country technical support for developing legislation and policy to support implementation of Article 5.3 of the FCTC in the Solomon Islands and Papua New Guinea. This paper examines the factors that have assisted the two Pacific countries to make progress in implementing Article 5.3 and what this might mean for supporting progress in other Pacific settings. A document analysis was undertaken to identify the process and outcome of the intervention. Two significant outputs from the project including having identified and documented specific examples of TII and the development of draft legislation for Article 5.3 and other key resources for public servants both within and outside the health sector. Key determinants of progress included a motivated and engaged Ministry of Health, active civil society group or champion and access to media to prepare tobacco industry related material to stimulate public and policy sector debate.

  20. Responses of algal communities to gradients in herbivore biomass and water quality in Marovo Lagoon, Solomon Islands

    NASA Astrophysics Data System (ADS)

    Albert, S.; Udy, J.; Tibbetts, I. R.

    2008-03-01

    Settlement tiles were used to characterise and quantify coral reef associated algal communities along water quality and herbivory gradients from terrestrial influenced near shore sites to oceanic passage sites in Marovo Lagoon, the Solomon Islands. After 6 months, settlement tile communities from inshore reefs were dominated by high biomass algal turfs (filamentous algae and cyanobacteria) whereas tiles located on offshore reefs were characterised by a mixed low biomass community of calcareous crustose algae, fleshy crustose algae and bare tile. The exclusion of macrograzers, via caging of tiles, on the outer reef sites resulted in the development of an algal turf community similar to that observed on inshore reefs. Caging on the inshore reef tiles had a limited impact on community composition or biomass. Water quality and herbivorous fish biomass were quantified at each site to elucidate factors that might influence algal community structure across the lagoon. Herbivore biomass was the dominant driver of algal community structure. Algal biomass on the other hand was controlled by both herbivory and water quality (particularly dissolved nutrients). This study demonstrates that algal communities on settlement tiles are an indicator capable of integrating the impacts of water quality and herbivory over a small spatial scale (kilometres) and short temporal scale (months), where other environmental drivers (current, light, regional variability) are constant.

  1. Impact of ethnic conflict on the nutritional status and quality of life of suburban villagers in the Solomon Islands.

    PubMed

    Yamauchi, Taro; Nakazawa, Minato; Ohmae, Hiroshi; Kamei, Kiseko; Sato, Kanae; Bakote'e, Bernard

    2010-01-01

    This paper describes the health and nutritional status and quality of life (QOL) of suburban villagers in the Solomon Islands 3 y after the 1998-2003 ethnic conflict. Cross-sectional data were obtained from a small community located 50 km east of the capital city (n=206, 87 adults and 119 children). A health survey involving urine analysis, anthropometry, and blood pressure measurements was conducted to assess health and nutritional status and child growth. Simultaneously, 57 non-randomly selected adults participated in the QOL questionnaire survey. Results of anthropometry show that participants had good health and nutritional status (mean BMIs: 22.8 and 21.7 for men and women, respectively) and 73% of boys and 83% of girls were judged `normal body size' based on their BMI values. Urinalysis revealed that 88% of the participants were healthy and indicated that they consumed considerable amounts of purchased food such as rice and tinned meat. These findings suggest that the population's lifestyle had essentially recovered from the ethnic conflict. However, possible consequences of the ethnic conflict on the QOL scores were observed in the environmental domain. This study found a positive association between body fat and QOL. This could be interpreted in terms of the traditionally positive view of large bodies in the South Pacific and as resulting from unstable social conditions prevailing after the ethnic conflict. PMID:20924144

  2. Elucidating the trophodynamics of four coral reef fishes of the Solomon Islands using δ15N and δ13C

    NASA Astrophysics Data System (ADS)

    Greenwood, N. D. W.; Sweeting, C. J.; Polunin, N. V. C.

    2010-09-01

    Size-related diet shifts are important characteristics of fish trophodynamics. Here, body size-related changes in muscle δ15N and δ13C of four coral reef fishes, Acanthurus nigrofuscus (herbivore), Chaetodon lunulatus (corallivore) , Chromis xanthura (planktivore) and Plectropomus leopardus (piscivore) were investigated at two locations in the Solomon Islands. All four species occupied distinct isotopic niches and the concurrent δ13C' values of C. xanthura and P. leopardus suggested a common planktonic production source. Size-related shifts in δ15N, and thus trophic level, were observed in C. xanthura, C. lunulatus and P. leopardus, and these trends varied between location, indicating spatial differences in trophic ecology. A literature review of tropical fishes revealed that positive δ15N-size trends are common while negative δ15N-size trends are rare. Size-δ15N trends fall into approximately equal groups representing size-based feeding within a food chain, and that associated with a basal resource shift and occurs in conjunction with changes in production source, indicated by δ13C. The review also revealed large scale differences in isotope-size trends and this, combined with small scale location differences noted earlier, highlights a high degree of plasticity in the reef fishes studied. This suggests that trophic size analysis of reef fishes would provide a productive avenue to identify species potentially vulnerable to reef impacts as a result of constrained trophic behaviour.

  3. From 'what' to 'how' -- capacity building in health promotion for HIV/AIDS prevention in the Solomon Islands.

    PubMed

    McPhail-Bell, Karen; MacLaren, David; Isihanua, Angela; MacLaren, Michelle

    2007-09-01

    This paper describes a capacity building process undertaken within the HIV/AIDS prevention project of the Adventist Development and Relief Agency (ADRA) in the Solomon Islands. ADRA HIV/AIDS has recently reoriented its project structure, moving beyond its awareness raising approach to incorporate health promotion frameworks, theories, strategies and assumptions. These have been used to inform project practice in project planning, delivery and evaluation. This paper shares what has worked and not worked in the capacity building process, including a project evaluation of the initial HIV/AIDS awareness raising project and the application of a number of capacity building strategies, including utilising a volunteer Australian Youth Ambassador for Development (AYAD) funded by the Australian Agency for International Development (AusAID). Existing and new projects are outlined. The underlying theme is that any capacity building exercise must include structural support (e.g. management, national frameworks) to ensure the incorporation of new initiatives and approaches. With time this enables ownership by counterparts and external partnerships to develop. The presence of an AYAD volunteer has been an effective strategy to achieve this. Reflections from the evaluators, the AYAD volunteer and the HIV/AIDS team are included. PMID:19588619

  4. Use of a duodenal serosal patch in the repair of a colon rupture in a female Solomon Island eclectus parrot.

    PubMed

    Briscoe, Jeleen A; Bennett, R Avery

    2011-04-01

    Case Description-A 444-g (0.98-lb) 4-year-old sexually intact female Solomon Island eclectus parrot (Eclectus roratus solomonensis) was referred and evaluated for a suspected colonic obstruction. Clinical Findings-The parrot had a 3-day history of not passing feces and lack of appetite following treatment of dystocia that included percutaneous collapse of the egg and manual removal of egg fragments via the cloaca. During this procedure, a tear in the cloacal mucosa developed. The tear was repaired via a midline cloacotomy. Although clinically stable at the time of referral, the parrot became lethargic and bradycardic and had delayed crop emptying. Treatment and Outcome-A midline celiotomy and cloacotomy were performed to relieve the colonic obstruction, during which the severely distended colon ruptured. The colonic defects were closed in a simple interrupted pattern, and a serosal patch was applied by use of the adjacent duodenum. The bird recovered uneventfully from anesthesia and was passing voluminous feces with mildly increased effort within 1 hour after surgery. At 3 weeks after surgery, the parrot was passing feces with no increase in effort and had a normal appetite. Clinical Relevance-Application of a duodenal serosal patch for repair of a colon rupture was successful in this parrot. Gastrointestinal obstruction is rare in birds, but should be considered in birds that have regurgitation, decreased fecal production, and gastrointestinal dilation. Because birds lack an omentum, serosal patching with adjacent duodenum should be considered as a viable option in avian surgery.

  5. Knowledge, Attitudes, and Practices regarding Diarrhea and Cholera following an Oral Cholera Vaccination Campaign in the Solomon Islands

    PubMed Central

    Burnett, Eleanor; Dalipanda, Tenneth; Ogaoga, Divi; Gaiofa, Jenny; Jilini, Gregory; Halpin, Alison; Dietz, Vance; Date, Kashmira; Mintz, Eric; Hyde, Terri; Wannemuehler, Kathleen; Yen, Catherine

    2016-01-01

    Background In response to a 2011 cholera outbreak in Papua New Guinea, the Government of the Solomon Islands initiated a cholera prevention program which included cholera disease prevention and treatment messaging, community meetings, and a pre-emptive cholera vaccination campaign targeting 11,000 children aged 1–15 years in selected communities in Choiseul and Western Provinces. Methodology and Principal Findings We conducted a post-vaccination campaign, household-level survey about knowledge, attitudes, and practices regarding diarrhea and cholera in areas targeted and not targeted for cholera vaccination. Respondents in vaccinated areas were more likely to have received cholera education in the previous 6 months (33% v. 9%; p = 0.04), to know signs and symptoms (64% vs. 22%; p = 0.02) and treatment (96% vs. 50%; p = 0.02) of cholera, and to be aware of cholera vaccine (48% vs. 14%; p = 0.02). There were no differences in water, sanitation, and hygiene practices. Conclusions This pre-emptive OCV campaign in a cholera-naïve community provided a unique opportunity to assess household-level knowledge, attitudes, and practices regarding diarrhea, cholera, and water, sanitation, and hygiene (WASH). Our findings suggest that education provided during the vaccination campaign may have reinforced earlier mass messaging about cholera and diarrheal disease in vaccinated communities. PMID:27548678

  6. The May 2003 eruption of Anatahan volcano, Mariana Islands: Geochemical evolution of a silicic island-arc volcano

    USGS Publications Warehouse

    Wade, J.A.; Plank, T.; Stern, R.J.; Tollstrup, D.L.; Gill, J.B.; O'Leary, J. C.; Eiler, J.M.; Moore, R.B.; Woodhead, J.D.; Trusdell, F.; Fischer, T.P.; Hilton, David R.

    2005-01-01

    The first historical eruption of Anatahan volcano began on May 10, 2003. Samples of tephra from early in the eruption were analyzed for major and trace elements, and Sr, Nd, Pb, Hf, and O isotopic compositions. The compositions of these tephras are compared with those of prehistoric samples of basalt and andesite, also newly reported here. The May 2003 eruptives are medium-K andesites with 59-63 wt.% SiO2, and are otherwise homogeneous (varying less than 3% 2?? about the mean for 45 elements). Small, but systematic, chemical differences exist between dark (scoria) and light (pumice) fragments, which indicate fewer mafic and oxide phenocrysts in, and less degassing for, the pumice than scoria. The May 2003 magmas are nearly identical to other prehistoric eruptives from Anatahan. Nonetheless, Anatahan has erupted a wide range of compositions in the past, from basalt to dacite (49-66 wt.% SiO2). The large proportion of lavas with silicic compositions at Anatahan (> 59 wt.% SiO2) is unique within the active Mariana Islands, which otherwise erupt a narrow range of basalts and basaltic andesites. The silicic compositions raise the question of whether they formed via crystal fractionation or crustal assimilation. The lack of 87Sr/86Sr variation with silica content, the MORB-like ??18O, and the incompatible behavior of Zr rule out assimilation of old crust, altered crust, or zircon-saturated crustal melts, respectively. Instead, the constancy of isotopic and trace element ratios, and the systematic variations in REE patterns are consistent with evolution by crystal fractionation of similar parental magmas. Thus, Anatahan is a type example of an island-arc volcano that erupts comagmatic basalts to dacites, with no evidence for crustal assimilation. The parental magmas to Anatahan lie at the low 143Nd/144Nd, Ba/La, and Sm/La end of the spectrum of magmas erupted in the Marianas arc, consistent with 1-3 wt.% addition of subducted sediment to the mantle source, or roughly one

  7. Source Rupture Process of the Solomon Islands Earthquake of April 1, 2007 Inferred from Teleseismic Body Waves

    NASA Astrophysics Data System (ADS)

    Biryol, C. B.; Beck, S. L.

    2007-12-01

    A large earthquake (Mw 8.1) followed by a tsunami took place in the southeast Pacific along the New Britain subduction zone on April 1, 2007. This region displays a complex tectonic nature where 4 plates intersect. Along the Solomon Island convergent margin the relatively small Woodlark and Solomon plates enter into the subduction zone side-by-side with the much larger Australia plate and the boundaries of these three plates are defined by transform faults. On a regional scale this subduction zone plate boundary is characterized by the occurrence of large earthquake doublets in 1971, 1974, 1975, 1977 and 2000. We investigated the source process of the April 1, 2007 earthquake using three different faulting patterns; (1) fixed thrust mechanism over the entire extend of the fault, (2) varying slip directions over the area of rupture and (3) varying focal mechanisms along the faulted region. The teleseismic body wave inversion technique that we used in our analysis of the source parameters for the three different fault models consistently yield a relatively large fault area (approximately 300 km by 50 km) with an overall seismic moment on the order of 1.0 x 1028 Nm. For the fixed mechanism and varying slip direction models, a major part of the seismic moment is released in the form of two pulses separated by 15-20 seconds. The second pulse is the largest one and it is located northwest of the hypocenter, implying a northwestward directed unilateral rupture. Our results indicate that the location of this maximum seismic moment release is close to the centroid location determined by Global CMT and also spatially coincides with the projected subduction of the transform boundary between the Australian and the Woodlark plates. The distribution of the dislocations computed for the varying slip direction model along the megathrust is characterized by three isolated patches of varying slip amounts and directions. One of these patches is located at the hypocenter of the event

  8. Successful Forecast of the Place of Great Solomon Islands Earthquake of April 1, 2007, Mw8.1

    NASA Astrophysics Data System (ADS)

    Purcaru, G.

    2007-12-01

    Predicting the large and great earhquakes proved to remain at present a complicated and most difficult problem, regarding the place and magnitude, and especially the time, on medium- or long-term interval, which is the principal component of any prediction. As a result a few (scientific) predictions are really successful, with a desired precision. False alarms and failures are by far dominant. However, the incresed number of higher accuracy data, advancements in the rupture- imaging at a smaller scale, seimotectonics details, increase of GPS data, different deterministic and probabilistic methods and numerical experimnts, retrospective predictions, etc. All these have to contribute, to increase a knowledge necessary to find better prediction-laws and methods in order to make particular earthquakes in specified regions more predictable. Along this view, we present a successful prediction (deterministic prediction) of a large earthquake in the Solomon Islands subduction zone: 154°E to 165°le E, where large earthquakes are occurring. We analized in detail historical earthquakes and aftershock areas (Kelleher et al, 1973, 1974; McCann et al 1979; Lay and Kanamori, 1980) of large events, their distribution and space and time, and the fluctuations of earthquake activity. We identified, in 1984, a seismic gap in the Central region of the subduction zone, with the boundary to No time prediction was made. The gap bundaries were fixed to NW at the SE-end of aftershock areas of the Jan - Feb. 1974 earthquake doublet (M7.0, M7.1) and to SE at the location of the Jan. 30, 1939 (Ms7.9-8.0) and its aftersock area was not known. The 2007 Solomon epicenter is well inside the gap. No evidence or rationale at that times would at least suggest that a future large earthquake in the gap will possibly rupture further to NW, and if the contrary than it is only a coincidence. Therefore the forecasted earthquake has closed very well the gap. The 6-days (also the 8-days) earthquake

  9. Origin of Japanese White-Eyes and Brown-Eared Bulbuls on the Volcano Islands.

    PubMed

    Sugita, Norimasa; Kawakami, Kazuto; Nishiumi, Isao

    2016-04-01

    The Ogasawara Archipelago comprises two groups of oceanic islands: the Bonin Islands, formed in the Paleogene, and the Volcano Islands, formed in the Quaternary. These groups are located within a moderate distance (ca. 160-270 km) of one another; thus, most land bird species are not distinguished as different subspecies. Two land birds, however, show unusual distribution. The Japanese white-eyes Zosterops japonicus originally inhabited only the Volcano Islands, but has been introduced to the Bonin Islands. The brown-eared bulbuls Hypsipetes amaurotis are distributed as a different subspecies. We investigated their genetic differences and divergences in the Ogasawara Archipelago using mitochondria DNA. The Volcano population of white-eyes had four endemic haplotypes that were divergent from one another, except for the Bonin population, which shared three haplotypes with the Volcano, Izu, and Ryukyu Islands and did not have any endemic haplotype. This is the first genetic suggestion that the Bonin population is a hybrid of introduced populations. With respect to bulbuls, the Volcano and Bonin Islands each had a single endemic haplotype. The Volcano haplotype is closest to a haplotype shared with Izu, the Japanese mainland, Daito and Ryukyu, whereas the Bonin haplotype is closest to one endemic to the south Ryukyu Islands. This indicates that the sources of the two bulbul populations can be geologically and temporally distinguished. The populations of the two species in the Ogasawara Archipelago are irreplaceable, owing to their genetic differences and should be regarded as evolutionarily significant units. In order to prevent introgression between the two populations, we must restrict interisland transfers.

  10. Origin of Japanese White-Eyes and Brown-Eared Bulbuls on the Volcano Islands.

    PubMed

    Sugita, Norimasa; Kawakami, Kazuto; Nishiumi, Isao

    2016-04-01

    The Ogasawara Archipelago comprises two groups of oceanic islands: the Bonin Islands, formed in the Paleogene, and the Volcano Islands, formed in the Quaternary. These groups are located within a moderate distance (ca. 160-270 km) of one another; thus, most land bird species are not distinguished as different subspecies. Two land birds, however, show unusual distribution. The Japanese white-eyes Zosterops japonicus originally inhabited only the Volcano Islands, but has been introduced to the Bonin Islands. The brown-eared bulbuls Hypsipetes amaurotis are distributed as a different subspecies. We investigated their genetic differences and divergences in the Ogasawara Archipelago using mitochondria DNA. The Volcano population of white-eyes had four endemic haplotypes that were divergent from one another, except for the Bonin population, which shared three haplotypes with the Volcano, Izu, and Ryukyu Islands and did not have any endemic haplotype. This is the first genetic suggestion that the Bonin population is a hybrid of introduced populations. With respect to bulbuls, the Volcano and Bonin Islands each had a single endemic haplotype. The Volcano haplotype is closest to a haplotype shared with Izu, the Japanese mainland, Daito and Ryukyu, whereas the Bonin haplotype is closest to one endemic to the south Ryukyu Islands. This indicates that the sources of the two bulbul populations can be geologically and temporally distinguished. The populations of the two species in the Ogasawara Archipelago are irreplaceable, owing to their genetic differences and should be regarded as evolutionarily significant units. In order to prevent introgression between the two populations, we must restrict interisland transfers. PMID:27032679

  11. Reconstructing palaeo-volcanic geometries using a Geodynamic Regression Model (GRM): Application to Deception Island volcano (South Shetland Islands, Antarctica)

    NASA Astrophysics Data System (ADS)

    Torrecillas, C.; Berrocoso, M.; Felpeto, A.; Torrecillas, M. D.; Garcia, A.

    2013-01-01

    This article describes a reconstruction made of the palaeo-volcanic edifice on Deception Island (South Shetland Islands, Antarctica) prior to the formation of its present caldera. Deception Island is an active Quaternary volcano located in the Bransfield Strait, between the South Shetland Islands and the Antarctic Peninsula. The morphology of the island has been influenced mainly by the volcanic activity but geodynamics and volcanic deformation have also contributed. A volcanic reconstruction method, the Geodynamic Regression Model (GRM), which includes a terrain deformation factor, is proposed. In the case of Deception Island, the directions of this deformation are NW-SE and NE-SW, and match both the observed deformation of the Bransfield Strait and the volcanic deformation monitored over the last 20 years in the island, using Global Navigation Satellite System (GNSS) techniques. Based on these data, possible volcanic deformation values of 5-15 mm/yr in these directions have been derived. A possible coastline derived from a current bathymetry is transformed, according to values for the chosen date, to obtain the palaeo-coastline of Deception Island of 100 k years ago. Topographic, geomorphologic, volcanological and geological data in a GIS system have been considered, for computation of the outside caldera slope, palaeo-coastline, palaeo-summit height and palaeo digital elevation model (DEM). The result is a 3D palaeo-geomorphological surface model of a volcano, reaching 640 m in height, with an increase of 4 km3 in volume compared to the current edifice, covering 4 km2 more surface area and the method reveals the previous existence of parasite volcanoes. Two photorealistic images of the island are obtained by superposition of textures extracted from a current Quick Bird satellite image also. This technique for reconstructing the terrain of an existing volcano could be useful for analysing the past and future geomorphology of this island and similar locations.

  12. Brucella abortus surveillance of cattle in Fiji, Papua New Guinea, Vanuatu, the Solomon Islands and a case for active disease surveillance as a training tool.

    PubMed

    Tukana, Andrew; Hedlefs, Robert; Gummow, Bruce

    2016-10-01

    There have been no surveys of the cattle population for brucellosis in the Pacific Island Countries and Territories (PICTs) for more than 15 years. This study used disease surveillance as a capacity building training tool and to examine some of the constraints that impede surveillance in PICTs. The study also developed and implemented a series of surveys for detecting antibodies to B. abortus in cattle in Fiji, Papua New Guinea, Vanuatu and the Solomon Islands contributing to OIE requirements. The findings indicated lack of funds, lack of technical capacity, shortage of veterinarians, high turnover of in-country officials and lack of awareness on the impacts of animal diseases on public health that were constraining active disease surveillance. During the development and implementation of the surveys, constraints highlighted were outdated census data on farm numbers and cattle population, lack of funds for mobilisation of officials to carry out the surveys, lack of equipment for collecting and processing samples, lack of staff knowledge on blood sampling, geographical difficulties and security in accessing farms. Some of the reasons why these were constraints are discussed with likely solutions presented. The detection surveys had the objectives of building capacity for the country officials and demonstrating freedom from brucellosis in cattle for PNG, Vanuatu and the Solomon Islands. PNG, Vanuatu and the Solomon Islands all demonstrated freedom from bovine brucellosis in the areas surveyed using the indirect ELISA test. Fiji had an outbreak of brucellosis, and the objective was to determine its distribution and prevalence on untested farms. The Muaniweni district surveyed during the training had a 95 % confidence interval for true prevalence between 1.66 and 5.45 %. The study showed that active disease surveillance could be used as a tool for training officials thus, improves surveillance capacity in resource poor countries.

  13. Brucella abortus surveillance of cattle in Fiji, Papua New Guinea, Vanuatu, the Solomon Islands and a case for active disease surveillance as a training tool.

    PubMed

    Tukana, Andrew; Hedlefs, Robert; Gummow, Bruce

    2016-10-01

    There have been no surveys of the cattle population for brucellosis in the Pacific Island Countries and Territories (PICTs) for more than 15 years. This study used disease surveillance as a capacity building training tool and to examine some of the constraints that impede surveillance in PICTs. The study also developed and implemented a series of surveys for detecting antibodies to B. abortus in cattle in Fiji, Papua New Guinea, Vanuatu and the Solomon Islands contributing to OIE requirements. The findings indicated lack of funds, lack of technical capacity, shortage of veterinarians, high turnover of in-country officials and lack of awareness on the impacts of animal diseases on public health that were constraining active disease surveillance. During the development and implementation of the surveys, constraints highlighted were outdated census data on farm numbers and cattle population, lack of funds for mobilisation of officials to carry out the surveys, lack of equipment for collecting and processing samples, lack of staff knowledge on blood sampling, geographical difficulties and security in accessing farms. Some of the reasons why these were constraints are discussed with likely solutions presented. The detection surveys had the objectives of building capacity for the country officials and demonstrating freedom from brucellosis in cattle for PNG, Vanuatu and the Solomon Islands. PNG, Vanuatu and the Solomon Islands all demonstrated freedom from bovine brucellosis in the areas surveyed using the indirect ELISA test. Fiji had an outbreak of brucellosis, and the objective was to determine its distribution and prevalence on untested farms. The Muaniweni district surveyed during the training had a 95 % confidence interval for true prevalence between 1.66 and 5.45 %. The study showed that active disease surveillance could be used as a tool for training officials thus, improves surveillance capacity in resource poor countries. PMID:27522595

  14. Preparedness of Pre-Service Teachers for Inclusive Education in the Solomon Islands

    ERIC Educational Resources Information Center

    Sharma, Umesh; Simi, Janine; Forlin, Chris

    2015-01-01

    Recent policy changes in the Pacific Islands have seen a strong emphasis on implementing inclusive education. Preparing teachers for this change in education will be essential if they are to have the knowledge, skills and understandings so that they can become inclusive practitioners. Pre-service teacher education will play a critical role in…

  15. Diet and social status on Taumako, a Polynesian outlier in the Southeastern Solomon Islands.

    PubMed

    Kinaston, Rebecca L; Buckley, Hallie R; Gray, Andrew

    2013-08-01

    Stable isotopes (δ(13)C, δ(15)N, and δ(34)S) are used to characterize the diet of the adult individuals (n = 99) interred in the Namu burial ground located on the Polynesian outlier of Taumako (∼300-750 BP). Polynesian outliers are islands on the fringe of Remote Oceania that were inhabited by a back migration of populations from Polynesia during prehistory. As a result of admixture with nearby island communities, little is known about the social structure and social diversity of the prehistoric inhabitants of Taumako. The distribution of prestige grave goods within the Namu cemetery has been used as evidence to support the premise that Taumakoan social structure was stratified like Polynesian societies. Here we test the hypothesis that "wealthy" individuals and males will display isotopic ratios indicative of the consumption of "high status" foods in the Pacific islands such as pork, chicken, sea turtle, and pelagic fish. The isotope results suggest the δ(34) S values were diagenetically altered, possibly an effect of volcanism. The carbon and nitrogen stable isotope ratios indicate that the diet of all the individuals included a mixture of C3 terrestrial plant foods (likely starchy staples such as yam, taro, and breadfruit, in addition to nuts) and a variety of marine resources, including reef and pelagic fish. The stable isotope results indicate that wealthy individuals and males were eating more foods from higher trophic levels, interpreted as being high status animal foods. The socially differentiated food consumption patterns are discussed within a Pacific island context.

  16. Embedded ARM system for volcano monitoring in remote areas: application to the active volcano on Deception Island (Antarctica).

    PubMed

    Peci, Luis Miguel; Berrocoso, Manuel; Fernández-Ros, Alberto; García, Alicia; Marrero, José Manuel; Ortiz, Ramón

    2014-01-01

    This paper describes the development of a multi-parameter system for monitoring volcanic activity. The system permits the remote access and the connection of several modules in a network. An embedded ARM™ processor has been used, allowing a great flexibility in hardware configuration. The use of a complete Linux solution (Debian™) as Operating System permits a quick, easy application development to control sensors and communications. This provides all the capabilities required and great stability with relatively low energy consumption. The cost of the components and applications development is low since they are widely used in different fields. Sensors and commercial modules have been combined with other self-developed modules. The Modular Volcano Monitoring System (MVMS) described has been deployed on the active Deception Island (Antarctica) volcano, within the Spanish Antarctic Program, and has proved successful for monitoring the volcano, with proven reliability and efficient operation under extreme conditions. In another context, i.e., the recent volcanic activity on El Hierro Island (Canary Islands) in 2011, this technology has been used for the seismic equipment and GPS systems deployed, thus showing its efficiency in the monitoring of a volcanic crisis.

  17. Embedded ARM System for Volcano Monitoring in Remote Areas: Application to the Active Volcano on Deception Island (Antarctica)

    PubMed Central

    Peci, Luis Miguel; Berrocoso, Manuel; Fernández-Ros, Alberto; García, Alicia; Marrero, José Manuel; Ortiz, Ramón

    2014-01-01

    This paper describes the development of a multi-parameter system for monitoring volcanic activity. The system permits the remote access and the connection of several modules in a network. An embedded ARM™™ processor has been used, allowing a great flexibility in hardware configuration. The use of a complete Linux solution (Debian™) as Operating System permits a quick, easy application development to control sensors and communications. This provides all the capabilities required and great stability with relatively low energy consumption. The cost of the components and applications development is low since they are widely used in different fields. Sensors and commercial modules have been combined with other self-developed modules. The Modular Volcano Monitoring System (MVMS) described has been deployed on the active Deception Island (Antarctica) volcano, within the Spanish Antarctic Program, and has proved successful for monitoring the volcano, with proven reliability and efficient operation under extreme conditions. In another context, i.e., the recent volcanic activity on El Hierro Island (Canary Islands) in 2011, this technology has been used for the seismic equipment and GPS systems deployed, thus showing its efficiency in the monitoring of a volcanic crisis. PMID:24451461

  18. Embedded ARM system for volcano monitoring in remote areas: application to the active volcano on Deception Island (Antarctica).

    PubMed

    Peci, Luis Miguel; Berrocoso, Manuel; Fernández-Ros, Alberto; García, Alicia; Marrero, José Manuel; Ortiz, Ramón

    2014-01-01

    This paper describes the development of a multi-parameter system for monitoring volcanic activity. The system permits the remote access and the connection of several modules in a network. An embedded ARM™ processor has been used, allowing a great flexibility in hardware configuration. The use of a complete Linux solution (Debian™) as Operating System permits a quick, easy application development to control sensors and communications. This provides all the capabilities required and great stability with relatively low energy consumption. The cost of the components and applications development is low since they are widely used in different fields. Sensors and commercial modules have been combined with other self-developed modules. The Modular Volcano Monitoring System (MVMS) described has been deployed on the active Deception Island (Antarctica) volcano, within the Spanish Antarctic Program, and has proved successful for monitoring the volcano, with proven reliability and efficient operation under extreme conditions. In another context, i.e., the recent volcanic activity on El Hierro Island (Canary Islands) in 2011, this technology has been used for the seismic equipment and GPS systems deployed, thus showing its efficiency in the monitoring of a volcanic crisis. PMID:24451461

  19. Diet and social status on Taumako, a Polynesian outlier in the Southeastern Solomon Islands.

    PubMed

    Kinaston, Rebecca L; Buckley, Hallie R; Gray, Andrew

    2013-08-01

    Stable isotopes (δ(13)C, δ(15)N, and δ(34)S) are used to characterize the diet of the adult individuals (n = 99) interred in the Namu burial ground located on the Polynesian outlier of Taumako (∼300-750 BP). Polynesian outliers are islands on the fringe of Remote Oceania that were inhabited by a back migration of populations from Polynesia during prehistory. As a result of admixture with nearby island communities, little is known about the social structure and social diversity of the prehistoric inhabitants of Taumako. The distribution of prestige grave goods within the Namu cemetery has been used as evidence to support the premise that Taumakoan social structure was stratified like Polynesian societies. Here we test the hypothesis that "wealthy" individuals and males will display isotopic ratios indicative of the consumption of "high status" foods in the Pacific islands such as pork, chicken, sea turtle, and pelagic fish. The isotope results suggest the δ(34) S values were diagenetically altered, possibly an effect of volcanism. The carbon and nitrogen stable isotope ratios indicate that the diet of all the individuals included a mixture of C3 terrestrial plant foods (likely starchy staples such as yam, taro, and breadfruit, in addition to nuts) and a variety of marine resources, including reef and pelagic fish. The stable isotope results indicate that wealthy individuals and males were eating more foods from higher trophic levels, interpreted as being high status animal foods. The socially differentiated food consumption patterns are discussed within a Pacific island context. PMID:23868172

  20. Mass drug administration of azithromycin for trachoma reduces the prevalence of genital Chlamydia trachomatis infection in the Solomon Islands

    PubMed Central

    Bottomley, C; Tome, H; Pitakaka, R; Butcher, R; Sokana, O; Kako, H; Solomon, A W; Mabey, D C

    2016-01-01

    Objectives Chlamydia trachomatis is the most common bacterial sexually transmitted infection and is frequently asymptomatic; ocular C. trachomatis strains cause trachoma. Mass drug administration (MDA) of azithromycin for trachoma might also reduce the prevalence of genital C. trachomatis. In a survey conducted in the Solomon Islands in 2014, prior to MDA, the prevalence of genital C. trachomatis was 20.3% (95% CI 15.9% to 25.4%). We conducted a survey to establish the impact of MDA with azithromycin on genital C. trachomatis. Methods Women attending three community outpatient clinics, predominantly for antenatal care, 10 months after MDA with azithromycin given for trachoma elimination, were enrolled in this survey. Self-taken high vaginal swabs were for C. trachomatis and Neisseria gonorrhoeae using the BD Probetec strand displacement assay. Results 298 women were enrolled. C. trachomatis infection was diagnosed in 43 women (14.4%, 95% CI 10.6% to 18.9%) and N. gonorrhoeae in 9 (3%, 95% CI 1.4% to 5.7%). The age-adjusted OR for C. trachomatis infection was consistent with a significant decrease in the prevalence of C. trachomatis following MDA (OR 0.58, 95% CI 0.37 to 0.94, p=0.027). There was no change in the prevalence of N. gonorrhoeae between following MDA (OR 0.51, 95% CI 0.22 to 1.22, p=0.13). Conclusions This study demonstrated a 40% reduction in the age-adjusted prevalence of genital C. trachomatis infection following azithromycin MDA for trachoma elimination. PMID:26888658

  1. Complex rupture processes of the Solomon Islands subduction zone earthquake and subduction controlled upper mantle structure beneath Anatolia

    NASA Astrophysics Data System (ADS)

    Biryol, Cemal Berk

    This dissertation explores subduction zone-related deformation both on short time scales in the form of subduction zone earthquakes and over larger time and geographical scales in the form of subduction rollback or detachment of the subducting lithosphere. The study presented here is composed of two parts. First, we analyzed the source-rupture processes of the April 1, 2007 Solomon Islands Earthquake (Mw=8.1) using a body-wave inversion technique. Our analysis indicated that the earthquake ruptured approximately 240 km of the southeast Pacific subduction zone in two sub-events. In the second part of this study, we used shear-wave splitting analysis to investigate the effects of the subducting African lithosphere on the upper-mantle flow field beneath the Anatolian Plate in the Eastern Mediterranean region. Our shear-wave splitting results are consistent with relatively uniform southwest-directed flow towards the actively southwestward-retreating Aegean slab. Based on spatial variations in observed delay times we identified varying flow speeds beneath Anatolia and we attribute this variation to the differential retreat rates of the Aegean and the Cyprean trenches. Finally, we used teleseismic P-wave travel-time tomography to image the geometry of the subducting African lithosphere beneath the Anatolia region. Our tomograms show that the subducting African lithosphere is partitioned into at least two segments along the Cyprean and the Aegean trenches. We observed a gap between the two segments through which hot asthenosphere ascends beneath the volcanic fields of western Anatolia. Our results show that the Cyprean slab is steeper than the Aegean slab. We inferred that this steep geometry, in part, controls the flow regime of asthenosphere beneath Anatolia causing variations in flow speeds inferred from shear-wave splitting analysis.

  2. Ancient recycled crust beneath the Ontong Java Plateau: Isotopic evidence from the garnet clinopyroxenite xenoliths, Malaita, Solomon Islands

    NASA Astrophysics Data System (ADS)

    Ishikawa, Akira; Kuritani, Takeshi; Makishima, Akio; Nakamura, Eizo

    2007-07-01

    We present a Sr, Nd, Hf and Pb isotope investigation of a set of garnet clinopyroxenite xenoliths from Malaita, Solomon Islands in order to constrain crustal recycling in the Pacific mantle. Geological, thermobarometric and petrochemical evidence from previous studies strongly support an origin as a series of high-pressure (> 3 GPa) melting residues of basaltic material incorporated in peridotite, which was derived from Pacific convective mantle related to the Ontong Java Plateau magmatism. The present study reveals isotopic variations in the pyroxenites that are best explained by different extents of chemical reaction with ambient peridotite in the context of a melting of composite source mantle. Isotopic compositions of bimineralic garnet clinopyroxenites affected by ambient peridotite fall within the oceanic basalt array, similar to those of Ontong Java Plateau lavas. In contrast, a quartz-garnet clinopyroxenite, whose major element compositions remain intact, has lower 206Pb/ 204Pb- 143Nd/ 144Nd and higher 87Sr/ 86Sr- 207Pb/ 204Pb ratios than most oceanic basalts. These isotopic signatures show some affinity with proposed recycled sources such as the so-called EM-1 or DUPAL types. Constraints from major and trace element characteristics of the quartz-garnet clinopyroxenite, the large extent of Hf-Nd isotopic decoupling and the good coincidence of Pb isotopes to the Stacey-Kramers curve, all indicate that pollution of southern Pacific mantle occurred by the subduction or delamination of Neoproterozoic granulitic lower crust (0.5-1 Ga). This crustal recycling could have taken place around the suture of Rodinia supercontinent, a part of which resurfaced during mantle upwelling responsible for creating the Cretaceous Ontong Java Plateau.

  3. A marked decline in the incidence of malaria in a remote region of Malaita, Solomon Islands, 2008 to 2013

    PubMed Central

    Oloifana-Polosovai, Hellen; Gwala, John; Harrington, Humpress; Massey, Peter D; Ribeyro, Elmer; Flores, Angelica; Speare, Christopher; McBride, Edwin; MacLaren, David

    2014-01-01

    Setting Atoifi Adventist Hospital (AAH), Solomon Islands, the only hospital in the East Kwaio region. Objective To use routine surveillance data to assess the trends in malaria from 2008 to 2013. Design Descriptive study of records from (1) AAH laboratory malaria records; (2) admissions to AAH for malaria; and (3) malaria treatments from outpatient records. Results AAH examined 35 608 blood films and diagnosed malaria in 4443 samples comprised of 2667 Plasmodium falciparum (Pf) and 1776 Plasmodium vivax (Pv). Between 2008 and 2013 the total number of malaria cases detected annually decreased by 86.5%, Pf by 96.7% and Pv by 65.3%. The ratio of Pf to Pv reversed in 2010 from 2.06 in 2008 to 0.19 in 2013. For 2013, Pf showed a seasonal pattern with no cases diagnosed in four months. From 2008 to 2013 admissions in AAH for malaria declined by 90.8%, and malaria mortality fell from 54 per 100 000 to zero. The annual parasite index (API) for 2008 and 2013 was 195 and 24, respectively. Village API has identified a group of villages with higher malaria incidence rates. Conclusion The decline in malaria cases in the AAH catchment area has been spectacular, particularly for Pf. This was supported by three sources of hospital surveillance data (laboratory, admissions and treatment records). The decline was associated with the use of artemisinin-based combined therapy and improved vertical social capital between the AAH and the local communities. Calculating village-specific API has highlighted which villages need to be targeted by the AAH malaria control team. PMID:25320674

  4. Population screening for glucose-6-phosphate dehydrogenase deficiencies in Isabel Province, Solomon Islands, using a modified enzyme assay on filter paper dried bloodspots

    PubMed Central

    2010-01-01

    Background Glucose-6-phosphate dehydrogenase deficiency poses a significant impediment to primaquine use for the elimination of liver stage infection with Plasmodium vivax and for gametocyte clearance, because of the risk of life-threatening haemolytic anaemia that can occur in G6PD deficient patients. Although a range of methods for screening G6PD deficiency have been described, almost all require skilled personnel, expensive laboratory equipment, freshly collected blood, and are time consuming; factors that render them unsuitable for mass-screening purposes. Methods A published WST8/1-methoxy PMS method was adapted to assay G6PD activity in a 96-well format using dried blood spots, and used it to undertake population screening within a malaria survey undertaken in Isabel Province, Solomon Islands. The assay results were compared to a biochemical test and a recently marketed rapid diagnostic test. Results Comparative testing with biochemical and rapid diagnostic test indicated that results obtained by filter paper assay were accurate providing that blood spots were assayed within 5 days when stored at ambient temperature and 10 days when stored at 4 degrees. Screening of 8541 people from 41 villages in Isabel Province, Solomon Islands revealed the prevalence of G6PD deficiency as defined by enzyme activity < 30% of normal control was 20.3% and a prevalence of severe deficiency that would predispose to primaquine-induced hemolysis (WHO Class I-II) of 6.9%. Conclusions The assay enabled simple and quick semi-quantitative population screening in a malaria-endemic region. The study indicated a high prevalence of G6PD deficiency in Isabel Province and highlights the critical need to consider G6PD deficiency in the context of P. vivax malaria elimination strategies in Solomon Islands, particularly in light of the potential role of primaquine mass drug administration. PMID:20684792

  5. Origin of the oceanic basalt basement of the Solomon Islands arc and its relationship to the Ontong Java Plateau-insights from Cenozoic plate motion models

    USGS Publications Warehouse

    Wells, R.E.

    1989-01-01

    Cenozoic global plate motion models based on a hotspot reference frame may provide a useful framework for analyzing the tectonic evolution of the Solomon Islands convergent margin. A postulated late Miocene collision of the Ontong Java Plateau (OJP) with a NE-facing arc is consistent with the predicted path of the OJP across the Pacific Basin and its Miocene arrival at the trench. Late-stage igneous activity (65-30 Ma) predicted for the OJP as it rode over the Samoan hotspot occurred in correlative stratigraphic sections on Malaita, the supposed accreted flake of OJP in the Solomon Islands arc. Convergence similar to the present velocities between Australia and the Pacific plates was characteristic of the last 43 million years. Prior to 43 Ma Pacific-Australia plate motions were divergent, seemingly at odds with geologic evidence for early Tertiary convergence, particularly in Papua New Guinea. A postulated South Pacific plate may have existed between Australia and the Pacific plate and would have allowed implied northward subduction along the northeastern Australia plate boundary that lasted into the early Eocene. Subsequent reorganization of plate motions in the middle Eocene correlates with middle Eocene marginal basin formation along ridges oblique to the main plate boundary. Cessation of spreading on the Pacific-South Pacific Ridge and its subsequent subduction beneath Asia followed the change in Pacific plate motion at 43 Ma. A trapped remnant of the extinct, NW-trending ridge may still lie beneath the western Philippine Sea. The terminal deformation, metamorphism and ophiolite obduction in the Eocene orogen of the southwest Pacific also correlates with the major change in Pacific plate motion at 43 Ma and the subsequent compression of the dying Eocene arc against outlying continental and oceanic crustal blocks of the Australian plate. The Solomon Islands oceanic basement may represent juxtaposition of oceanic plateaus of the Australian plate beneath

  6. Accelerating late Quaternary uplift of the New Georgia Island Group (Solomon island arc) in response to subduction of the recently active Woodlark spreading center and Coleman seamount

    NASA Astrophysics Data System (ADS)

    Mann, Paul; Taylor, Frederick W.; Lagoe, Martin B.; Quarles, Andrew; Burr, G.

    1998-10-01

    The New Georgia Island Group of the Solomon Islands is one of four places where an active or recently active spreading ridge has subducted beneath an island arc. We have used coral reef terraces, paleobathymetry of Neogene sedimentary rocks, and existing marine geophysical data to constrain patterns of regional Quaternary deformation related to subduction of the recently active Woodlark spreading center and its overlying Coleman seamount. These combined data indicate the following vertical tectonic history for the central part of the New Georgia Island Group: (1) subsidence of the forearc region (Tetepare and Rendova Islands) to water depths of ˜1500 m and deposition of marine turbidites until after 270 ka; (2) late Quaternary uplift of the forearc to sea level and erosion of an unconformity; (3) subsidence of the forearc to ˜500 m BSL and deposition of bathyal sediments; and (4) uplift of the forearc above sea level with Holocene uplift rates up to at least 7.5 mm/yr on Tetepare and 5 mm/yr on Rendova. In the northeastern part of the New Georgia Island Group, our combined data indicate a slightly different tectonic history characterized by lower-amplitude vertical motions and a more recent change from subsidence to uplift. Barrier reefs formed around New Georgia and Vangunu Islands as they subsided >300 m. By 50-100 ka, subsidence was replaced by uplift that accelerated to Holocene rates of ˜1 mm/yr on the volcanic arc compared with rates up to ˜7.5 mm/yr in the forearc area of Tetepare and Rendova. Uplift mechanisms, such as thermal effects due to subduction of spreading ridges, tectonic erosion, or underplating of deeply subducted bathymetric features, are not likely to function on the 270-ka period that these uplift events have occurred in the New Georgia Island Group. A more likely uplift mechanism for the post-270-ka accelerating uplift of the forearc and volcanic arc of the New Georgia Island Group is progressive impingement of the Coleman seamount or

  7. Cyclic Explosivity in High Elevation Phreatomagmatic Eruptions at Ocean Island Volcanoes: Implications for Aquifer Pressurization and Volcano Flank Destabilization.

    NASA Astrophysics Data System (ADS)

    Tarff, R.; Day, S. J.; Downes, H.; Seghedi, I.

    2015-12-01

    Groundwater heating and pressurization of aquifers trapped between dikes in ocean island volcanoes has been proposed as a mechanism for destabilizing and triggering large-volume flank collapses. Previous modelling has indicated that heat transfer from sustained magma flow through dikes during eruption has the potential to produce destabilizing levels of pressure on time scales of 4 to 400 days, if the aquifers remain confined. Here we revisit this proposal from a different perspective. We examine evidence for pressure variations in dike-confined aquifers during eruptions at high elevation vents on ocean island volcanoes. Initially magmatic, these eruptions change to mostly small-volume explosive phreatomagmatic activity. A recent example is the 1949 eruption on La Palma, Canary Islands. Some such eruptions involve sequences of larger-volume explosive phases or cycles, including production of voluminous low-temperature, pyroclastic density currents (PDC). Here we present and interpret data from the Cova de Paul crater eruption (Santo Antao, Cape Verde Islands). The phreatomagmatic part of this eruption formed two cycles, each culminating with eruption of PDCs. Compositional and textural variations in the products of both cycles indicate that the diatreme fill began as coarse-grained and permeable which allowed gas to escape. During the eruption, the fill evolved to a finer grained, poorly sorted, less permeable material, in which pore fluid pressures built up to produce violent explosive phases. This implies that aquifers adjacent to the feeder intrusion were not simply depressurized at the onset of phreatomagmatic explosivity but experienced fluctuations in pressure throughout the eruption as the vent repeatedly choked and emptied. In combination with fluctuations in magma supply rate, driving of aquifer pressurization by cyclical vent choking will further complicate the prediction of flank destabilization during comparable eruptions on ocean island volcanoes.

  8. Preliminary analysis of the earthquake (MW 8.1) and tsunami of April 1, 2007, in the Solomon Islands, southwestern Pacific Ocean

    USGS Publications Warehouse

    Fisher, Michael A.; Geist, Eric L.; Sliter, Ray; Wong, Florence L.; Reiss, Carol; Mann, Dennis M.

    2007-01-01

    On April 1, 2007, a destructive earthquake (Mw 8.1) and tsunami struck the central Solomon Islands arc in the southwestern Pacific Ocean. The earthquake had a thrust-fault focal mechanism and occurred at shallow depth (between 15 km and 25 km) beneath the island arc. The combined effects of the earthquake and tsunami caused dozens of fatalities and thousands remain without shelter. We present a preliminary analysis of the Mw-8.1 earthquake and resulting tsunami. Multichannel seismic-reflection data collected during 1984 show the geologic structure of the arc's frontal prism within the earthquake's rupture zone. Modeling tsunami-wave propagation indicates that some of the islands are so close to the earthquake epicenter that they were hard hit by tsunami waves as soon as 5 min. after shaking began, allowing people scant time to react.

  9. A high-resolution geospatial surveillance-response system for malaria elimination in Solomon Islands and Vanuatu

    PubMed Central

    2013-01-01

    Background A high-resolution surveillance-response system has been developed within a geographic information system (GIS) to support malaria elimination in the Pacific. This paper examines the application of a GIS-based spatial decision support system (SDSS) to automatically locate and map the distribution of confirmed malaria cases, rapidly classify active transmission foci, and guide targeted responses in elimination zones. Methods Customized SDSS-based surveillance-response systems were developed in the three elimination provinces of Isabel and Temotu, Solomon Islands and Tafea, Vanuatu. Confirmed malaria cases were reported to provincial malaria offices upon diagnosis and updated into the respective SDSS as part of routine operations throughout 2011. Cases were automatically mapped by household within the SDSS using existing geographical reconnaissance (GR) data. GIS queries were integrated into the SDSS-framework to automatically classify and map transmission foci based on the spatiotemporal distribution of cases, highlight current areas of interest (AOI) regions to conduct foci-specific targeted response, and extract supporting household and population data. GIS simulations were run to detect AOIs triggered throughout 2011 in each elimination province and conduct a sensitivity analysis to calculate the proportion of positive cases, households and population highlighted in AOI regions of a varying geographic radius. Results A total of 183 confirmed cases were reported and mapped using the SDSS throughout 2011 and used to describe transmission within a target population of 90,354. Automatic AOI regions were also generated within each provincial SDSS identifying geographic areas to conduct response. 82.5% of confirmed cases were automatically geo-referenced and mapped at the household level, with 100% of remaining cases geo-referenced at a village level. Data from the AOI analysis indicated different stages of progress in each province, highlighting operational

  10. Coral record of paleoseismic uplifts at Ranongga Island, Western Solomon Islands megathrust: Was the 2007 Mw 8.1 event smaller than usual?

    NASA Astrophysics Data System (ADS)

    Taylor, F. W.; Thirumalai, K.; Shen, C.; WU, C.; Papabatu, A.; Lavier, L. L.; Bevis, M. G.

    2012-12-01

    The timing and amount of vertical displacements associated with past megathrust earthquakes provide the best available insights into the amounts of interplate slip that have been accommodated as coseismic slip versus other mechanisms. At Ranongga Island, Western Solomon Islands, a Mw 8.1 earthquake in 2007 helps us to calibrate the relationship between a megathrust rupture and the geography and amounts of vertical displacement recorded by reef crest corals. Along the coasts of Ranongga, parts of which have uplifted at mean rates exceeding 5 mm/yr, we discovered corals that had been raised by a series of earthquakes in the millennia before the 2007 event. The penultimate earthquake (pre-2007), which occurred around 600 years ago (U-series calendar year), was manifest as a 'level' of raised corals about 1.6 m above the 2007 level. However, in the decades preceding the 2007 event (which had imposed a coseismic uplift of 1.3 m), rapid subsidence had subtracted significant amounts of uplift imposed by the penultimate earthquake. Similarly, the sequence of three additional uplift events, preceding the penultimate event, extending to elevations up to 16 m higher than the corals raised by the 2007 event, appear to have been larger uplifts than the 2007 event. This suggests two things: 1. Many previous megathrust events caused more uplift and perhaps involved greater interplate coseismic slip, and 2. There are too few megathrust rupture events to account for the approximately 80-100 m of plate convergence that must be processed each millennium. Thus, a significant amount of plate convergence must be accommodated by mechanisms other than coseismic slip.

  11. Seismological, Geological and Geomorphic Aspects of Arc Segmentation and Their Relation to Subducting Bathymetric Features in the Solomon Island Arc, SW Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Chen, M.; Frohlich, C.; Taylor, F. W.

    2006-12-01

    Arc segmentation partitions forearcs into multiple blocks so that the forearc behaves like a "keyboard on a piano" as each segment potentially interacts with the downgoing plate in a different tectonic style. For example, parts of the forearc of the Solomon Islands arc has undergone hundreds of meters of rapid subsidence and uplift during late Quaternary time. Other parts have undergone only minor late Quaternary movements. We use seismology, geology, and geomorphology to identify arc segments in order to evaluate how bathymetric features on the subducting plate influence seismicity and active tectonics and cause overriding plate segmentation. Seismic rupture areas for large earthquakes, seismicity patterns, seismicity cross sections, focal mechanisms, and seismic moment calculations all reveal that the central arc being underthrust by the Woodlark Basin system of active sea-floor spreading is very different from the northwest and southeast parts of the arc. Woodlark subduction is characterized by sparse seismicity, gentle subduction angle, and thrust faulting with some normal and strike-slip components. Observations from geologic maps, coastal geomorphology, and emerged coral reefs show that the arc segments are undergoing varying amounts and rates of uplift and submergence. Larger islands such as Guadalcanal and San Cristobal have both drowning and emerging coastlines. This information indicates the individual segments have dramatically different histories of vertical tectonics. We identify three supersegments: Bougainville, New Georgia, and Guadalcanal-San Cristobal. Smaller segments subdivide each supersegment. Thus we identify nine major boundaries, seven minor boundaries, and six possible boundaries. The classification of each boundary depends on the strength of evidence supporting its existence and the amount of change in tectonic behavior across the boundary. We speculate that subduction of the young Woodlark Spreading Center with seamounts and ridges on

  12. Volcanoes

    ERIC Educational Resources Information Center

    Kunar, L. N. S.

    1975-01-01

    Describes the forces responsible for the eruptions of volcanoes and gives the physical and chemical parameters governing the type of eruption. Explains the structure of the earth in relation to volcanoes and explains the location of volcanic regions. (GS)

  13. Post-eruptive morphological evolution of island volcanoes: Surtsey as a modern case study

    NASA Astrophysics Data System (ADS)

    Romagnoli, C.; Jakobsson, S. P.

    2015-12-01

    Surtsey is a small volcanic island in the Vestmannaeyjar archipelago, off the south coast of Iceland. The eruption leading to the island's emersion lasted for 3.5 yr (1963-1967) while destructive forces have been active for over 50 yr (1963-present-day) during which Surtsey has suffered rapid subaerial and submarine erosion and undergone major morphological changes. Surtsey is a well-documented modern example of the post-eruptive degradational stage of island volcanoes, and has provided the unique opportunity to continuously observe and quantify the effects of intense geomorphic processes. In this paper we focus on coastal and marine processes re-shaping the shoreline and shallow-water portions of the Surtsey complex since its formation and on the related geomorphological record. Analogies with the post-eruptive morphological evolution of recently active island volcanoes at the emerging stage, encompassing different climatic conditions, wave regimes and geological contexts, are discussed.

  14. Volcanoes

    SciTech Connect

    Decker, R.W.; Decker, B.

    1989-01-01

    This book describes volcanoes although the authors say they are more to be experienced than described. This book poses more question than answers. The public has developed interest and awareness in volcanism since the first edition eight years ago, maybe because since the time 120 volcanoes have erupted. Of those, the more lethal eruptions were from volcanoes not included in the first edition's World's 101 Most Notorious Volcanoes.

  15. Volcanoes.

    ERIC Educational Resources Information Center

    Tilling, Robert I.

    One of a series of general interest publications on science topics, this booklet provides a non-technical introduction to the subject of volcanoes. Separate sections examine the nature and workings of volcanoes, types of volcanoes, volcanic geological structures such as plugs and maars, types of eruptions, volcanic-related activity such as geysers…

  16. Coseismic Dip Slip Distribution of the 1 Apr 2007 Solomon Islands Mw8.1 Earthquake from a Fully Bayesian Inversion

    NASA Astrophysics Data System (ADS)

    Chen, T.

    2009-12-01

    102 uplift and subsidence measurements over the southeastern end of the rupture zone from two field surveys shortly after 1 Apr 2007 Solomon Islands Earthquake provide a unique geodetic constraint in the following inversion of distributed slip. In the conventional inversion of geodetic data for spatial distribution of fault slip the solution is maintained by minimizing the second-order spatial derivative of slip and the smoothing parameter is often selected subjectively at the bend of the trade-off curve of misfit as a function of slip roughness. A fully Bayesian slip inversion method[Fukuda et al.,2008] is used to overcome the deficiency of selecting the smoothing parameter subjectively. The smoothing parameter is estimated with the distributed slip at the same time under a unified theoretical Bayesian framework. The joint posterior probability density function of distributed slip and smoothing parameter is formulated using Bayes’ theorem and sampled with Markov chain Monte Carlo method. I will apply this method to coseismic slip distribution associated with the 2007 Mw8.1 Solomon Islands earthquake and compare the results of this method with conventional method and the coseismic finite fault model of Furlong et al.[2009].

  17. Monitoring of the eruption of the Sarychev Peak Volcano in Matua Island in 2009 (central Kurile islands)

    NASA Astrophysics Data System (ADS)

    Levin, B. W.; Rybin, A. V.; Vasilenko, N. F.; Prytkov, A. S.; Chibisova, M. V.; Kogan, M. G.; Steblov, G. M.; Frolov, D. I.

    2010-11-01

    In June 2009, one of the greatest eruptions of the Sarychev Peak volcano in Matua Island (48°06' N, 153°12' E) for the recent historical period occurred. With the help of satellite sounding methods, the first signs of volcanic activity were recorded and all the stages of the explosive eruption were traced. During the expeditionary investigations in the active volcano, unique data on the character of the eruption were obtained. The volume of erupted material was 0.4 cubic km, which lead to an increased area of Matua Island by 1.4 square km. The GPS observation station set at the distance of 7 km from the volcano recorded the rapid displacement of the Earths's surface during the first two days of the active phase of eruption. This eruption of the Sarychev Peak volcano occurred 2.5 years after the catastrophic Simushir earthquakes in the period of intensive relaxation of stresses in the middle of the central part of the Kurile island arc.

  18. High Rates of Asymptomatic, Sub-microscopic Plasmodium vivax Infection and Disappearing Plasmodium falciparum Malaria in an Area of Low Transmission in Solomon Islands

    PubMed Central

    Waltmann, Andreea; Darcy, Andrew W.; Harris, Ivor; Koepfli, Cristian; Lodo, John; Vahi, Ventis; Piziki, David; Shanks, G. Dennis; Barry, Alyssa E.; Whittaker, Maxine; Kazura, James W.; Mueller, Ivo

    2015-01-01

    Introduction Solomon Islands is intensifying national efforts to achieve malaria elimination. A long history of indoor spraying with residual insecticides, combined recently with distribution of long lasting insecticidal nets and artemether-lumefantrine therapy, has been implemented in Solomon Islands. The impact of these interventions on local endemicity of Plasmodium spp. is unknown. Methods In 2012, a cross-sectional survey of 3501 residents of all ages was conducted in Ngella, Central Islands Province, Solomon Islands. Prevalence of Plasmodium falciparum, P. vivax, P. ovale and P. malariae was assessed by quantitative PCR (qPCR) and light microscopy (LM). Presence of gametocytes was determined by reverse transcription quantitative PCR (RT-qPCR). Results By qPCR, 468 Plasmodium spp. infections were detected (prevalence = 13.4%; 463 P. vivax, five mixed P. falciparum/P. vivax, no P. ovale or P. malariae) versus 130 by LM (prevalence = 3.7%; 126 P. vivax, three P. falciparum and one P. falciparum/P. vivax). The prevalence of P. vivax infection varied significantly among villages (range 3.0–38.5%, p<0.001) and across age groups (5.3–25.9%, p<0.001). Of 468 P. vivax infections, 72.9% were sub-microscopic, 84.5% afebrile and 60.0% were both sub-microscopic and afebrile. Local residency, low education level of the household head and living in a household with at least one other P. vivax infected individual increased the risk of P. vivax infection. Overall, 23.5% of P. vivax infections had concurrent gametocytaemia. Of all P. vivax positive samples, 29.2% were polyclonal by MS16 and msp1F3 genotyping. All five P. falciparum infections were detected in residents of the same village, carried the same msp2 allele and four were positive for P. falciparum gametocytes. Conclusion P. vivax infection remains endemic in Ngella, with the majority of cases afebrile and below the detection limit of LM. P. falciparum has nearly disappeared, but the risk of re-introductions and

  19. Magma Differentiation in the Plumbing System of an Alkaline Ocean Island Volcano (Fuerteventura, Canary Island).

    NASA Astrophysics Data System (ADS)

    Tornare, E.; Bussy, F.; Pilet, S.

    2014-12-01

    Magma differentiation and mixing are generally regarded as taking place in magma chambers, sills or reservoirs, while magma stagnates before continuing to ascent or erupt. Here we consider differentiation to occur during magma rise in vertical dykes, as documented in the PX1 pluton, Fuerteventura, which is part of the root-zone of an eroded ocean island volcano. PX1 is a vertically layered cumulative body composed of meter to decameter-wide bands of clinopyroxenites and gabbros, surrounded by a very high-grade contact aureole (ca. 1000°C, Hobson et al., 1998). Many clinopyroxenites are characterized by a coarse-grained texture and complexly zoned clinopyroxene crystals. Resorption features and reverse zoning observed in rims are evidence for successive pulses. Percolation of high temperature basaltic melts through the accumulating crystal-rich mush would generate the complexly zoned clinopyroxenes and lead to crystal coarsening. We interpret these coarse-grained clinopyroxenites as crystal-rich magma channels, through which sustained magma fluxes travelled to the surface over a long period of time, thus generating the contact aureole. On the other hand, gabbro bands are interpreted as sluggish magma pulses emplaced in a cooler environment during the waning stages of magmatic activity. We thus propose a model of magma differentiation by dynamic fractionation in dykes throughout magma ascent in the plumbing system of basaltic volcanoes. This model assumes fractional crystallization of continuously rising magmas in vertical channels all along their way to the surface through phenocryst accumulation and crystal-melt interaction processes.

  20. Tree Plantation Systems Influence Nitrogen Retention and the Abundance of Nitrogen Functional Genes in the Solomon Islands

    PubMed Central

    Reverchon, Frédérique; Bai, Shahla H.; Liu, Xian; Blumfield, Timothy J.

    2015-01-01

    Tree mono-plantations are susceptible to soil nutrient impoverishment and mixed species plantations have been proposed as a way of maintaining soil fertility while enhancing biodiversity. In the Solomon Islands, mixed species plantations where teak (Tectona grandis) is inter-planted with a local tree species (Flueggea flexuosa) have been used as an alternative to teak mono-plantations and are expected to increase soil microbial diversity and modify microbial biogeochemical processes. In this study, we quantified the abundance of microbial functional genes involved in the nitrogen (N) cycle from soil samples collected in teak, flueggea, and mixed species plantations. Furthermore, we measured soil properties such as pH, total carbon (C) and total N, stable N isotope composition (δ15N), and inorganic N pools. Soil pH and δ15N were higher under teak than under flueggea, which indicates that intercropping teak with flueggea may decrease bacterial activities and potential N losses. Higher C:N ratios were found under mixed species plantations than those under teak, suggesting an enhancement of N immobilization that would help preventing fast N losses. However, inorganic N pools remained unaffected by plant cover. Inter-planting teak with flueggea in mixed species plantations generally increased the relative abundance of denitrification genes and promoted the enrichment of nosZ-harboring denitrifiers. However, it reduced the abundance of bacterial amoA (ammonia monooxygenase) genes compared to teak mono-plantations. The abundance of most denitrification genes correlated with soil total N and C:N ratio, while bacterial and archeal nitrification genes correlated positively with soil NH4+ concentrations. Altogether, these results show that the abundance of bacterial N-cycling functional guilds vary under teak and under mixed species plantations, and that inter-planting teak with flueggea may potentially alleviate N losses associated with nitrification and denitrification

  1. Monitoring of malaria parasite resistance to chloroquine and sulphadoxine-pyrimethamine in the Solomon Islands by DNA microarray technology

    PubMed Central

    2010-01-01

    Background Little information is available on resistance to anti-malarial drugs in the Solomon Islands (SI). The analysis of single nucleotide polymorphisms (SNPs) in drug resistance associated parasite genes is a potential alternative to classical time- and resource-consuming in vivo studies to monitor drug resistance. Mutations in pfmdr1 and pfcrt were shown to indicate chloroquine (CQ) resistance, mutations in pfdhfr and pfdhps indicate sulphadoxine-pyrimethamine (SP) resistance, and mutations in pfATPase6 indicate resistance to artemisinin derivatives. Methods The relationship between the rate of treatment failure among 25 symptomatic Plasmodium falciparum-infected patients presenting at the clinic and the pattern of resistance-associated SNPs in P. falciparum infecting 76 asymptomatic individuals from the surrounding population was investigated. The study was conducted in the SI in 2004. Patients presenting at a local clinic with microscopically confirmed P. falciparum malaria were recruited and treated with CQ+SP. Rates of treatment failure were estimated during a 28-day follow-up period. In parallel, a DNA microarray technology was used to analyse mutations associated with CQ, SP, and artemisinin derivative resistance among samples from the asymptomatic community. Mutation and haplotype frequencies were determined, as well as the multiplicity of infection. Results The in vivo study showed an efficacy of 88% for CQ+SP to treat P. falciparum infections. DNA microarray analyses indicated a low diversity in the parasite population with one major haplotype present in 98.7% of the cases. It was composed of fixed mutations at position 86 in pfmdr1, positions 72, 75, 76, 220, 326 and 356 in pfcrt, and positions 59 and 108 in pfdhfr. No mutation was observed in pfdhps or in pfATPase6. The mean multiplicity of infection was 1.39. Conclusion This work provides the first insight into drug resistance markers of P. falciparum in the SI. The obtained results indicated the

  2. Tree Plantation Systems Influence Nitrogen Retention and the Abundance of Nitrogen Functional Genes in the Solomon Islands.

    PubMed

    Reverchon, Frédérique; Bai, Shahla H; Liu, Xian; Blumfield, Timothy J

    2015-01-01

    Tree mono-plantations are susceptible to soil nutrient impoverishment and mixed species plantations have been proposed as a way of maintaining soil fertility while enhancing biodiversity. In the Solomon Islands, mixed species plantations where teak (Tectona grandis) is inter-planted with a local tree species (Flueggea flexuosa) have been used as an alternative to teak mono-plantations and are expected to increase soil microbial diversity and modify microbial biogeochemical processes. In this study, we quantified the abundance of microbial functional genes involved in the nitrogen (N) cycle from soil samples collected in teak, flueggea, and mixed species plantations. Furthermore, we measured soil properties such as pH, total carbon (C) and total N, stable N isotope composition (δ(15)N), and inorganic N pools. Soil pH and δ(15)N were higher under teak than under flueggea, which indicates that intercropping teak with flueggea may decrease bacterial activities and potential N losses. Higher C:N ratios were found under mixed species plantations than those under teak, suggesting an enhancement of N immobilization that would help preventing fast N losses. However, inorganic N pools remained unaffected by plant cover. Inter-planting teak with flueggea in mixed species plantations generally increased the relative abundance of denitrification genes and promoted the enrichment of nosZ-harboring denitrifiers. However, it reduced the abundance of bacterial amoA (ammonia monooxygenase) genes compared to teak mono-plantations. The abundance of most denitrification genes correlated with soil total N and C:N ratio, while bacterial and archeal nitrification genes correlated positively with soil NH4 (+) concentrations. Altogether, these results show that the abundance of bacterial N-cycling functional guilds vary under teak and under mixed species plantations, and that inter-planting teak with flueggea may potentially alleviate N losses associated with nitrification and

  3. The bionomics of the malaria vector Anopheles farauti in Northern Guadalcanal, Solomon Islands: issues for successful vector control

    PubMed Central

    2014-01-01

    Background The north coast of Guadalcanal has some of the most intense malaria transmission in the Solomon Islands. And, there is a push for intensified vector control in Guadalcanal, to improve the livelihood of residents and to minimize the number of cases, which are regularly exported to the rest of the country. Therefore, the bionomics of the target vector, Anopheles farauti, was profiled in 2007–08; which was after 20 years of limited surveillance during which time treated bed nets (ITNs) were distributed in the area. Methods In three villages on northern Guadalcanal, blood-seeking female mosquitoes were caught using hourly human landing catches by four collectors, two working indoors and two outdoors, from 18.00-06.00 for at least two nights per month from July 2007 to June 2008. The mosquitoes were counted, identified using morphological and molecular markers and dissected to determine parity. Results Seasonality in vector densities was similar in the three villages, with a peak at the end of the drier months (October to December) and a trough at the end of the wetter months (March to May). There was some variability in endophagy (indoor biting) and nocturnal biting (activity during sleeping hours) both spatially and temporally across the longitudinal dataset. The general biting pattern was consistent throughout all sample collections, with the majority of biting occurring outdoors (64%) and outside of sleeping hours (65%). Peak biting was 19.00-20.00. The proportion parous across each village ranged between 0.54-0.58. Parity showed little seasonal trend despite fluctuations in vector densities over the year. Conclusion The early, outdoor biting behaviour of An. farauti documented 20 years previously on north Guadalcanal was still exhibited. It is possible that bed net use may have maintained this biting profile though this could not be determined unequivocally. The longevity of these populations has not changed despite long-term ITN use. This early

  4. Deep intrusions, lateral magma transport and related uplift at ocean island volcanoes

    NASA Astrophysics Data System (ADS)

    Klügel, Andreas; Longpré, Marc-Antoine; García-Cañada, Laura; Stix, John

    2015-12-01

    Oceanic intraplate volcanoes grow by accumulation of erupted material as well as by coeval or discrete magmatic intrusions. Dykes and other intrusive bodies within volcanic edifices are comparatively well studied, but intrusive processes deep beneath the volcanoes remain elusive. Although there is geological evidence for deep magmatic intrusions contributing to volcano growth through uplift, this has rarely been demonstrated by real-time monitoring. Here we use geophysical and petrological data from El Hierro, Canary Islands, to show that intrusions from the mantle and subhorizontal transport of magma within the oceanic crust result in rapid endogenous island growth. Seismicity and ground deformation associated with a submarine eruption in 2011-2012 reveal deep subhorizontal intrusive sheets (sills), which have caused island-scale uplift of tens of centimetres. The pre-eruptive intrusions migrated 15-20 km laterally within the lower oceanic crust, opening pathways that were subsequently used by the erupted magmas to ascend from the mantle to the surface. During six post-eruptive episodes between 2012 and 2014, further sill intrusions into the lower crust and upper mantle have caused magma to migrate up to 20 km laterally, resulting in magma accumulation exceeding that of the pre-eruptive phase. A comparison of geobarometric data for the 2011-2012 El Hierro eruption with data for other Atlantic intraplate volcanoes shows similar bimodal pressure distributions, suggesting that eruptive phases are commonly accompanied by deep intrusions of sills and lateral magma transport. These processes add significant material to the oceanic crust, cause uplift, and are thus fundamentally important for the growth and evolution of volcanic islands. We suggest that the development of such a magma accumulation zone in the lower oceanic crust begins early during volcano evolution, and is a consequence of increasing size and complexity of the mantle reservoir system, and potentially

  5. Active submarine volcano sampled

    USGS Publications Warehouse

    Taylor, B.

    1983-01-01

    On June 4, 1982, two full dredge hauls of fresh lava were recovered from the upper flanks of Kavachi submarine volcano, Solomon Islands, in the western Pacific Ocean, from the water depths of 1,200 and 2,700 feet. the shallower dredge site was within 0.5 mile of the active submarine vent shown at the surface by an area of slick water, probably caused by gas emissions. Kavachi is a composite stratovolcano that has been observed to erupt every year or two for at least the last 30 years (see photographs). An island formed in 1952, 1961, 1965, and 1978; but, in each case, it rapidly eroded below sea level. The latest eruption was observed by Solair pilots during the several weeks up to and including May 18, 1982. 

  6. Geochemistry and solute fluxes of volcano-hydrothermal systems of Shiashkotan, Kuril Islands

    NASA Astrophysics Data System (ADS)

    Kalacheva, Elena; Taran, Yuri; Kotenko, Tatiana

    2015-04-01

    Shiashkotan Island belongs to the Northern Kuril island arc and consists of two joined volcanoes, Sinarka and Kuntomintar, with about 18 km of distance between the summits. Both volcanoes are active, with historic eruptions, and both emit fumarolic gases. Sinarka volcano is degassing through the extrusive dome with inaccessible strong and hot (> 400 °C) fumaroles. A large fumarolic field of the Kuntomintar volcano situated in a wide eroded caldera-like crater hosts many fumarolic vents with temperatures from boiling point to 480 °C. Both volcanoes are characterized by intense hydrothermal activity discharging acid SO4-Cl waters, which are drained to the Sea of Okhotsk by streams. At least 4 groups of near-neutral Na-Mg-Ca-Cl-SO4 springs with temperatures in the range of 50-80 °C are located at the sea level, within tide zones and discharge slightly altered diluted seawater. Volcanic gas of Kuntomintar as well as all types of hydrothermal manifestations of both volcanoes were collected and analyzed for major and trace elements and water isotopes. Volcanic gases are typical for arc volcanoes with 3He/4He corrected for air contamination up to 6.4 Ra (Ra = 1.4 × 10- 6, the air ratio) and δ13C (CO2) within - 10‰ to - 8 ‰ VPDB. Using a saturation indices approach it is shown that acid volcanic waters are formed at a shallow level, whereas waters of the coastal springs are partially equilibrated with rocks at ~ 180 °C. Trace element distribution and concentrations and the total REE depend on the water type, acidity and Al + Fe concentration. The REE pattern for acidic waters is unusual but similar to that found in some acidic crater lake waters. The total hydrothermal discharge of Cl and S from the island associated with volcanic activity is estimated at ca. 20 t/d and 40 t/d, respectively, based on the measurements of flow rates of the draining streams and their chemistry. The chemical erosion of the island by surface and thermal waters is estimated at 27 and

  7. 2010 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; Herrick, Julie; Girina, O.A.; Chibisova, Marina; Rybin, Alexander; McGimsey, Robert G.; Dixon, Jim

    2014-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, volcanic unrest or suspected unrest at 12 volcanic centers in Alaska during 2010. The most notable volcanic activity consisted of intermittent ash emissions from long-active Cleveland volcano in the Aleutian Islands. AVO staff also participated in hazard communication regarding eruptions or unrest at seven volcanoes in Russia as part of an ongoing collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  8. The pattern of circumferential and radial eruptive fissures on the volcanoes of Fernandina and Isabela islands, Galapagos

    USGS Publications Warehouse

    Chadwick, W.W.; Howard, K.A.

    1991-01-01

    Maps of the eruptive vents on the active shield volcanoes of Fernandina and Isabela islands, Galapagos, made from aerial photographs, display a distinctive pattern that consists of circumferential eruptive fissures around the summit calderas and radial fissures lower on the flanks. On some volcano flanks either circumferential or radial eruptions have been dominant in recent time. The location of circumferential vents outside the calderas is independent of caldera-related normal faults. The eruptive fissures are the surface expression of dike emplacement, and the dike orientations are interpreted to be controlled by the state of stress in the volcano. Very few subaerial volcanoes display a pattern of fissures similar to that of the Galapagos volcanoes. Some seamounts and shield volcanoes on Mars morphologically resemble the Galapagos volcanoes, but more specific evidence is needed to determine if they also share common structure and eruptive style. ?? 1991 Springer-Verlag.

  9. Shoreline changes and vertical displacement of the 2 April 2007 Solomon Islands earthquake Mw 8.1 revealed by ALOS PALSAR images

    NASA Astrophysics Data System (ADS)

    Lubis, Ashar Muda; Isezaki, Nobuhiro

    The Solomon Islands earthquake with magnitude Mw = 8.1 occurred on 2 April 2007 at 7:39 local time. We used six L-band Synthetic Aperture Radar (SAR) images acquired by the Advanced Land Observing Satellite (ALOS) Array L-band Synthetic Aperture Radar (PALSAR) data to roughly estimate the shoreline and vertical displacements associated with this earthquake. We processed the raw SAR data with the SIGMA-SAR software package, produced by Japan Aerospace Exploration Agency (JAXA). Our measurements showed good agreement with field observations performed by Japanese scientists just a few weeks after the earthquake. We estimated the dislocation related to this earthquake between Ranongga Island and Simbo Island. Moreover, we compared the radar imagery analysis data with Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data and found that the SAR images were more efficient for investigating vertical displacements than similar techniques based on data from optical sensors. Measurements of offset cross-correlation intensities in SAR images indicated about 1.4 m of uplift on southwestern New Georgia Island.

  10. Comparative study of two tsunamigenic earthquakes in the Solomon Islands: 2015 Mw 7.0 normal-fault and 2013 Santa Cruz Mw 8.0 megathrust earthquakes

    NASA Astrophysics Data System (ADS)

    Heidarzadeh, Mohammad; Harada, Tomoya; Satake, Kenji; Ishibe, Takeo; Gusman, Aditya Riadi

    2016-05-01

    The July 2015 Mw 7.0 Solomon Islands tsunamigenic earthquake occurred ~40 km north of the February 2013 Mw 8.0 Santa Cruz earthquake. The proximity of the two epicenters provided unique opportunities for a comparative study of their source mechanisms and tsunami generation. The 2013 earthquake was an interplate event having a thrust focal mechanism at a depth of 30 km while the 2015 event was a normal-fault earthquake occurring at a shallow depth of 10 km in the overriding Pacific Plate. A combined use of tsunami and teleseismic data from the 2015 event revealed the north dipping fault plane and a rupture velocity of 3.6 km/s. Stress transfer analysis revealed that the 2015 earthquake occurred in a region with increased Coulomb stress following the 2013 earthquake. Spectral deconvolution, assuming the 2015 tsunami as empirical Green's function, indicated the source periods of the 2013 Santa Cruz tsunami as 10 and 22 min.

  11. Stratigraphic framework of Holocene volcaniclastic deposits, Akutan Volcano, east-central Aleutian Islands, Alaska

    USGS Publications Warehouse

    Waythomas, C.F.

    1999-01-01

    Akutan Volcano is one of the most active volcanoes in the Aleutian arc, but until recently little was known about its history and eruptive character. Following a brief but sustained period of intense seismic activity in March 1996, the Alaska Volcano Observatory began investigating the geology of the volcano and evaluating potential volcanic hazards that could affect residents of Akutan Island. During these studies new information was obtained about the Holocene eruptive history of the volcano on the basis of stratigraphic studies of volcaniclastic deposits and radiocarbon dating of associated buried soils and peat. A black, scoria-bearing, lapilli tephra, informally named the 'Akutan tephra,' is up to 2 m thick and is found over most of the island, primarily east of the volcano summit. Six radiocarbon ages on the humic fraction of soil A-horizons beneath the tephra indicate that the Akutan tephra was erupted approximately 1611 years B.P. At several locations the Akutan tephra is within a conformable stratigraphic sequence of pyroclastic-flow and lahar deposits that are all part of the same eruptive sequence. The thickness, widespread distribution, and conformable stratigraphic association with overlying pyroclastic-flow and lahar deposits indicate that the Akutan tephra likely records a major eruption of Akutan Volcano that may have formed the present summit caldera. Noncohesive lahar and pyroclastic-flow deposits that predate the Akutan tephra occur in the major valleys that head on the volcano and are evidence for six to eight earlier Holocene eruptions. These eruptions were strombolian to subplinian events that generated limited amounts of tephra and small pyroclastic flows that extended only a few kilometers from the vent. The pyroclastic flows melted snow and ice on the volcano flanks and formed lahars that traveled several kilometers down broad, formerly glaciated valleys, reaching the coast as thin, watery, hyperconcentrated flows or water floods. Slightly

  12. Source Process of the Solomon Islands Earthquake of April 1st, 2007 (Mw8.1) Based on SAR Data and its Tectonic Implications

    NASA Astrophysics Data System (ADS)

    Mori, M.; Kato, T.; Furuya, M.; Ochi, T.; Miyazaki, S.; Aoki, Y.

    2008-12-01

    We analyzed SAR (Synthetic Aperture Radar) data to derive the crustal deformation due to the Solomon Islands earthquake (Mw8.1) that occurred on April 1st, 2007. Three tracks that cover the source areas were used and the image data taken before and after the earthquake were processed to make interferograms. Then, we examined the obtained interferograms if the previous two source models that were obtained by seismic wave form inversion analyses could reproduce them. However, none of the models were able to reproduce the crustal deformations derived from the SAR data analysis. Then, we tried to construct a source model that explains the observed crustal deformations well. We considered some geophysical data to constrain the source geometry; the multichannel reflection data and observed vertical deformations using coral reef survey. Considering these lines of evidence, we introduced two possible source geometries; one is single-segment model that assumes only shallow-dipping (10 deg.) main thrust ruptured, and the other is two-segment model that assumes both a high angle spray fault of 30 degree dip and the main thrust fault slipped. The comparison of models based on inversion analyses suggested that the two-segment model would be preferable. This result suggests that the Solomon Islands earthquake would be the first observed earthquake on a steeply dipping splay fault that ruptured off the main converging plate boundary. If this is the case, this earthquake might provide us with an important clue for understanding the mechanisms of land formation such as landward titling of the coastal terraces.

  13. Estimate of sulfate emitted from Sakurajima volcano to the Japanese Islands

    SciTech Connect

    Mizuno, Tateki; Maeda, Takahisa; Tanaka, Chie; Takeuchi, Kiyohide

    1996-12-31

    Concentration of sulfate increased in a summer night over the wide area of the Kanto plain. Since the effect of long range transport of particulate sulfurs was suggested, Lagrangian dispersion-advection analysis of particles was carried out using global scale weather analytical data. Results show that the concentration observed at the Kanto plain coupled be increased by the effect of the volcanic gas which had been emitted from an active volcano {open_quotes}Sakurajima{close_quotes}, located in the distance of about 1,00 km at south-west of the Kanto area, before 3 days. This phenomenon suggests that sulfate emitted from the active volcano Sakurajima might affect acid deposition of all over the Japanese Islands. This report shows estimated concentration of deposition of sulfate from Sakurajima to the Japan Islands using the same model applied to the Kanto area.

  14. Seismic signature of a phreatic explosion: Hydrofracturing damage at Karthala volcano, Grande Comore Island, Indian Ocean

    USGS Publications Warehouse

    Savin, C.; Grasso, J.-R.; Bachelery, P.

    2005-01-01

    Karthala volcano is a basaltic shield volcano with an active hydrothermal system that forms the southern two-thirds of the Grande Comore Island, off the east coat of Africa, northwest of Madagascar. Since the start of volcano monitoring by the local volcano observatory in 1988, the July 11th, 1991 phreatic eruption was the first volcanic event seismically recorded on this volcano, and a rare example of a monitored basaltic shield. From 1991 to 1995 the VT locations, 0.5volcanoes, during the climax of the 1991 phreatic explosion, are due to the activation of the whole hydrothermal system, as roughly sized by the distribution of VT hypocenters. The seismicity rate in 1995 was still higher than the pre-eruption seismicity rate, and disagrees with the time pattern of thermo-elastic stress readjustment induced by single magma intrusions at basaltic volcanoes. We propose that it corresponds to the still ongoing relaxation of pressure heterogeneity within the hydrothermal system as suggested by the few LP events that still occurred in 1995. ?? Springer-Verlag 2005.

  15. Volcanoes

    USGS Publications Warehouse

    Tilling, Robert I.; ,

    1998-01-01

    Volcanoes destroy and volcanoes create. The catastrophic eruption of Mount St. Helens on May 18, 1980, made clear the awesome destructive power of a volcano. Yet, over a time span longer than human memory and record, volcanoes have played a key role in forming and modifying the planet upon which we live. More than 80 percent of the Earth's surface--above and below sea level--is of volcanic origin. Gaseous emissions from volcanic vents over hundreds of millions of years formed the Earth's earliest oceans and atmosphere, which supplied the ingredients vital to evolve and sustain life. Over geologic eons, countless volcanic eruptions have produced mountains, plateaus, and plains, which subsequent erosion and weathering have sculpted into majestic landscapes and formed fertile soils.

  16. The 2003 phreatomagmatic eruptions of Anatahan volcano - Textural and petrologic features of deposits at an emergent island volcano

    USGS Publications Warehouse

    Pallister, J.S.; Trusdell, F.A.; Brownfield, I.K.; Siems, D.F.; Budahn, J.R.; Sutley, S.F.

    2005-01-01

    Stratigraphic and field data are used in conjunction with textural and chemical evidence (including data from scanning electron microscope, electron microprobe, X-ray fluorescence, X-ray diffraction, and instrumental neutron activation analysis) to establish that the 2003 eruption of Anatahan volcano was mainly phreatomagmatic, dominated by explosive interaction of homogeneous composition low-viscosity crystal-poor andesite magma with water. The hydromagmatic mode of eruption contributed to the significant height of initial eruptive columns and to the excavation and eruption of altered rock debris from the sub-volcanic hydrothermal system. Volatile contents of glass inclusions in equilibrium phenocrysts less abundances of these constituents in matrix glass times the estimated mass of juvenile magma indicate minimum emissions of 19 kt SO2 and 13 kt Cl. This petrologic estimate of SO2 emission is an order-of-magnitude less than an estimate from TOMS. Similarly, inferred magma volumes from the petrologic data are an order of magnitude greater than those modeled from deformation data. Both discrepancies indicate additional sources of volatiles, likely derived from a separate fluid phase in the magma. The paucity of near-source volcanic-tectonic earthquakes preceding the eruption, and the dominance of sustained long-period tremor are attributed to the ease of ascent of the hot low-viscosity andesite, followed by a shallow phreatomagmatic mode of eruption. Phreatomagmatic eruptions are probably more common at emergent tropical island volcanoes, where shallow fresh-water lenses occur at near-sea-level vents. These relations suggest that phreatomagmatic explosions contributed to the formation of many of the near-sea-level craters and possibly even to the small calderas at the other Mariana islands.

  17. Subduction of very rugged seafloor topography imposes stronger interplate coupling and elevated mean stress levels at the Western Solomon Islands forearc

    NASA Astrophysics Data System (ADS)

    Taylor, F. W.; Lavier, L. L.; Bevis, M. G.; Frohlich, C. A.; Grand, S.; Papabatu, A. K.

    2010-12-01

    Recent large thrusting earthquakes in the context of paleoseismicity and GPS data indicate that only ~ 50 per cent of Australian plate convergence at the Western Solomon Islands forearc is accommodated by megathrust rupture. No instrumentally recorded events larger than M ~7.0 occurred in this region until the Mw 8.1 event of April 2007 and a Mw 7.1 event in January 2010. The 2007 event apparently ruptured to the base of the seismogenic zone with typical uplift of the outer forearc and subsidence of islands located greater than 40 km from the trench. The Mw 7.1 event of 2010 occurred to the east at the adjacent segment very near the trench where the Coleman seamount is impinging on the forearc. Just arcward of the epicenter, Rendova and Tetepare Islands subsided indicating that all of the coseismic slip occurred beneath the ~15 km strip separating these islands from the trench. This movement is opposite in direction to the geologic record of episodic uplifts of these islands at mean rates up to 7-8 mm/yr. Thus both the 2007 and 2010 earthquakes may have transferred stress to the deeper seismogenic zone arcward of the 2010 earthquake. The extremely rugged and young subducting seafloor at this margin resists subduction very strongly and induces very strong interplate coupling. Thus we propose that this margin operates at an elevated stress level. Such strong coupling impedes subduction and thus megathrust rupture occurs more rarely than if coupling were weaker. Forearc deformation as well as occasional megathrust ruptures may combine to accommodate plate convergence. We propose that initiation of rapid forearc uplift marked the beginning of the current episode of very strong interplate coupling and elevated forearc stress when some combination of seamounts and ridges on the downgoing plate began to impinge more forcefully on the forearc backstop.

  18. The 7-8 August 2008 eruption of Kasatochi Volcano, central Aleutian Islands, Alaska

    NASA Astrophysics Data System (ADS)

    Waythomas, Christopher F.; Scott, William E.; Prejean, Stephanie G.; Schneider, David J.; Izbekov, Pavel; Nye, Christopher J.

    2010-12-01

    Kasatochi volcano in the central Aleutian Islands erupted unexpectedly on 7-8 August 2008. Kasatochi has received little study by volcanologists and has had no confirmed historical eruptions. The island is an important nesting area for seabirds and a long-term biological study site of the U.S. Fish and Wildlife Service. After a notably energetic preeruptive earthquake swarm, the volcano erupted violently in a series of explosive events beginning in the early afternoon of 7 August. Each event produced ash-gas plumes that reached 14-18 km above sea level. The volcanic plume contained large amounts of SO2 and was tracked around the globe by satellite observations. The cumulative volcanic cloud interfered with air travel across the North Pacific, causing many flight cancelations that affected thousands of travelers. Visits to the volcano in 2008-2009 indicated that the eruption generated pyroclastic flows and surges that swept all flanks of the island, accumulated several tens of meters of pyroclastic debris, and increased the diameter of the island by about 800 m. Pyroclastic flow deposits contain abundant accidental lithic debris derived from the inner walls of the Kasatochi crater. Juvenile material is crystal-rich silicic andesite that ranges from slightly pumiceous to frothy pumice. Fine-grained pyroclastic surge and fall deposits with accretionary lapilli cover the lithic-rich pyroclastic flow deposits and mark a change in eruptive style from episodic explosive activity to more continuous ash emission with smaller intermittent explosions. Pyroclastic deposits completely cover the island, but wave erosion and gully development on the flanks have begun to modify the surface mantle of volcanic deposits.

  19. Whakaari (White Island volcano, New Zealand): Magma-hydrothermal laboratory

    NASA Astrophysics Data System (ADS)

    Lavallee, Yan; Heap, Michael J.; Reuschle, Thierry; Mayer, Klaus; Scheu, Bettina; Gilg, H. Albert; Kennedy, Ben M.; Letham-Brake, Mark; Jolly, Arthur; Dingwell, Donald B.

    2015-04-01

    Whakaari, active andesitic stratovolcano of the Taupo Volcanic Zone (New Zealand), hosts an open, highly reactive hydrothermal system in the amphitheatre of an earlier sector collapse. Its recent volcanic activity is primarily characterized by sequences of steam-driven (phreatic) and phreatomagmatic explosive eruptions, although a lava dome briefly extruded in 2012. The volcano provides a natural laboratory for the study of aggressive fluids on the permeability of the hydrothermal system, on phreatomagmatic volcanism as well as on the volcano edifice structural stability. Here, we present a holistic experimental dataset on the reservoir rocks properties (mineralogy, permeability, seismic velocity) and their response to changes in stress (strength, deformation mechanisms, fragmentation) and temperature (mineralogical breakdown). We show that the advance degree of alteration in the system, nearly replaced all the original rock-forming minerals. This alteration has produced generally weak rocks, which, when subjected to a differential stress, can undergo transition from a dilatant response (brittle) to a compactant response with a mere confining pressure of about 15-20 MPa (corresponding to depth of about 1 km). Thermal stressing experiments reveal that the alteration phases breakdown at 500 °C (alunite) and 700 °C (dehydrated alum and sulphur), generating much weakened skeletal rocks, deteriorated by a mass loss of 20 wt.%, resulting in an increase in porosity and permeability of about 15 vol.% and an order of magnitude, respectively. Novel thermal stressing tests at high-heating rates (<1000 K/min) suggest that the onset of this mineralogical debilitation is pushed to higher temperatures with heating rates, carrying implication for the stability of the reservoir rocks and explosions during magma movement at variable rates in the upper edifice. Rock strength imposes an important control on the stability of volcanic edifices and of the hydrothermal reservoir rocks

  20. Seasonal abundance and biting behaviour of Anopheles punctulatus and An. koliensis in Malaita Province, Solomon Islands, and a trial of permethrin impregnated bednets against malaria transmission.

    PubMed

    Samarawickrema, W A; Parkinson, A D; Kere, N; Galo, O

    1992-10-01

    Seasonal abundance of the malaria vectors Anopheles punctulatus Dönitz and An.koliensis Owen in Bilimanu, an isolated inland village with forty-two houses in Malaita Province of the Solomon Islands, was monitored over 28 months by means of all-night landing/biting catches at one site during June 1985 to September 1987. Totals of 1250 An.punctulatus and 141 An.koliensis were collected, the latter being the largest number of this species ever caught at any locality in the Solomons. Bednets impregnated with permethrin 0.5 g/m2 were introduced in December 1986 to be used at night by all 190 villagers for protection against malaria vectors. Bioassay tests with An.punctulatus blood-fed females exposed under nets for 10 min resulted in 100% mortality up to 50 weeks post-impregnation. For An.punctulatus, the main vector species, the mean catch (indoors + outdoors) per man hour was 2.9 (range 0.7-13.2) before a cyclone on 19 May 1986, and, 0.66 (0.2-2.7) after the cyclone. The vector survival rates were usually high before the cyclone, but erratically lower thereafter for An.punctulatus. An.koliensis disappeared after the cyclone. Both An.punctulatus and An.koliensis consistently showed higher rates of biting man indoors than outdoors and their diel biting cycle showed a peak around midnight. Outdoors, the parous proportion of An.punctulatus was twice the nulliparous, and nearly so indoors. Following intervention with permethrin-treated bednets, the mean catch of An.punctulatus fell to 0.35 per man-hour (monthly range 0-1.5). The Plasmodium falciparum malaria infection rate reduced from 10% pre-intervention to zero in September 1987, 9 months after intervention, and then rose again.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1463904

  1. A new model for the formation of linear rift zones on oceanic island volcanoes

    NASA Astrophysics Data System (ADS)

    Kluegel, A.; Walter, T. R.

    2003-04-01

    Oceanic island volcanoes commonly contain rift zones along which eruptive centers and parallel dike complexes are concentrated. Formation and orientation of rifts often remain enigmatic, however. Tectonic lineaments and regional zones of weakness facilitating magma ascent may be one reason of rift evolution, e.g. Sao Jorge (Azores) or Iceland. Alternatively, gravity tectonics of a volcano may cause formation of dike swarms oriented parallel to the line of contact between overlapping volcanic edifices (e.g. Kilauea / Mauna Loa, Hawaiian Islands). We have evidence that spreading of overlapping edifices can produce two types and orientations of dike complexes. A direction perpendicular to classic "Kilauea type" rifts is typified in the pronounced rift zones of La Palma (Canary Islands) and Madeira/Desertas islands. We suggest that these rift systems formed by edifice coalescence with a main spreading zone perpendicular to the initial line of contact between two volcanoes. Intrusions and eruptions focused along the resulting rift connecting the once separated volcanic cones, which successively grew together. Based on experimental studies we show that this mechanism works if the edifices overlap at lower (submarine) slopes and are situated both on weak substratum. By mounting analogue sand piles onto a viscous PDMS substratum, the setups represented the presumed pre-rift situations at La Palma and Madeira with small initial cones adjacent to the larger shields. Gravitative spreading of these cones produced fractures that mimic the orientation of both islands' present rift zones. The results are in agreement with the observation of an apparently old submarine cone at the southern end of the La Palma rift zone. Likewise, on Madeira, the terminal parts of the Desertas rift arm and of a recently discovered submarine rift zone off the island are both marked by a concentration of eruptive centers. Our results may also provide a clue why the rift zone of Loihi seamount (Hawaii

  2. Esmeralda Bank: Geochemistry of an active submarine volcano in the Mariana Island Arc

    NASA Astrophysics Data System (ADS)

    Stern, Robert J.; Bibee, L. D.

    1984-05-01

    Esmeralda Bank is the southernmost active volcano in the Izu-Volcano-Mariana Arc. This submarine volcano is one of the most active vents in the western Pacific. It has a total volume of about 27 km3, rising to within 30 m of sea level. Two dredge hauls from Esmeralda recovered fresh, nearly aphyric, vesicular basalts and basaltic andesites and minor basaltic vitrophyre. These samples reflect uniform yet unusual major and trace element chemistries. Mean abundances of TiO2 (1.3%) and FeO* (12.6%) are higher and CaO (9.2%) and Al2O3 (15.1%) are lower than rocks of similar silica content from other active Mariana Arc volcanoes. Mean incompatible element ratios K/Rb (488) and K/Ba (29) of Esmeralda rocks are indistinguishable from those of other Mariana Arc volcanoes. On a Ti-Zr plot, Esmeralda samples plot in the field of oceanic basalts while other Mariana Arc volcanic rocks plot in the field for island arcs. Incompatible element ratios K/Rb and K/Ba and isotopic compositions of Sr (87Sr/86Sr=0.70342 0.70348), Nd (ɛND=+7.6 to +8.1), and O(δ18O=+5.8 to +5.9) are incompatible with models calling for the Esmeralda source to include appreciable contributions from pelagic sediments or fresh or altered abyssal tholeiite from subduction zone melting. Instead, incompatible element and isotopic ratios of Esmeralda rocks are similar to those of intra-plate oceanic islands or “hot-spot” volcanoes in general and Kilauean tholeiites in particular. The conclusion that the source for Esmeralda lavas is an ocean-island type mantle reservoir is preferred. Esmeralda Bank rare earth element patterns are inconsistent with models calling for residual garnet in the source region, but are adequately modelled by 7 10% equilibrium partial melting of spinel lherzolite. This is supported by consideration of the results of melting experiments at 20 kbars, 1,150° C with CO2 and H2O as important volatile components. These experiments further indicate that low MgO (4.1%), MgO/FeO*(0.25) and

  3. Low Prevalence of Conjunctival Infection with Chlamydia trachomatis in a Treatment-Naïve Trachoma-Endemic Region of the Solomon Islands

    PubMed Central

    Butcher, Robert M. R.; Sokana, Oliver; Jack, Kelvin; Macleod, Colin K.; Marks, Michael E.; Kalae, Eric; Sui, Leslie; Russell, Charles; Tutill, Helena J.; Williams, Rachel J.; Breuer, Judith; Willis, Rebecca; Le Mesurier, Richard T.; Mabey, David C. W.; Solomon, Anthony W.; Roberts, Chrissy h.

    2016-01-01

    Background Trachoma is endemic in several Pacific Island states. Recent surveys across the Solomon Islands indicated that whilst trachomatous inflammation—follicular (TF) was present at levels warranting intervention, the prevalence of trachomatous trichiasis (TT) was low. We set out to determine the relationship between chlamydial infection and trachoma in this population. Methods We conducted a population-based trachoma prevalence survey of 3674 individuals from two Solomon Islands provinces. Participants were examined for clinical signs of trachoma. Conjunctival swabs were collected from all children aged 1–9 years. We tested swabs for Chlamydia trachomatis (Ct) DNA using droplet digital PCR. Chlamydial DNA from positive swabs was enriched and sequenced for use in phylogenetic analysis. Results We observed a moderate prevalence of TF in children aged 1–9 years (n = 296/1135, 26.1%) but low prevalence of trachomatous inflammation—intense (TI) (n = 2/1135, 0.2%) and current Ct infection (n = 13/1002, 1.3%) in children aged 1–9 years, and TT in those aged 15+ years (n = 2/2061, 0.1%). Ten of 13 (76.9%) cases of infection were in persons with TF or TI (p = 0.0005). Sequence analysis of the Ct-positive samples yielded 5/13 (38%) complete (>95% coverage of reference) genome sequences, and 8/13 complete plasmid sequences. Complete sequences all aligned most closely to ocular serovar reference strains. Discussion The low prevalence of TT, TI and Ct infection that we observed are incongruent with the high proportion of children exhibiting signs of TF. TF is present at levels that apparently warrant intervention, but the scarcity of other signs of trachoma indicates the phenotype is mild and may not pose a significant public health threat. Our data suggest that, whilst conjunctival Ct infection appears to be present in the region, it is present at levels that are unlikely to be the dominant driving force for TF in the population. This could be one reason for the

  4. The 2008 Eruption of Kasatochi Volcano, Central Aleutian Islands, Alaska: Reconnaissance Observations and Preliminary Physical Volcanology

    NASA Astrophysics Data System (ADS)

    Waythomas, C. F.; Schneider, D. J.; Prejean, S. G.

    2008-12-01

    The August 7, 2008 eruption of Kasatochi volcano was the first documented historical eruption of this small (3 x 3 km) island volcano with a 1 km2 lake filled crater in the central Aleutian Islands of Alaska. Reports of previous Kasatochi eruptions are unconfirmed and lacking in detail and little is known about the eruptive history. Three explosively-generated ash plumes reaching altitudes of 15 to 20 km were observed in satellite data and were preceded by some of the most intense seismicity yet recorded by the Alaska Volcano Observatory (AVO) seismic network. Eruptive products on Kasatochi Island observed on August 22 and 23 consist of pumice-bearing, lithic-rich pyroclastic-flow deposits overlain by a 1-2 m thick sequence of fine- grained pyroclastic-surge, and -fall deposits all exposed at the coastline. These deposits completely blanket Kasatochi Island to a depth of many meters. Pyroclastic flows entered the sea and extended the coastline 300-400 m beyond prominent wave cut cliffs and sea stacks. Tide gauge data from Adak Island, 80 km to the west, indicate a small tsunami with maximum water amplitude of 20 cm, was initiated during the eruption. Kasatochi volcano lacks a real-time seismic monitoring network. Seismic activity was detected by AVO instruments on Great Sitkin Island 40 km to the west, and thus the timing of eruptive events is approximate. The eruption began explosively at 2201 UTC on August 7, and was followed by at least two additional strong eruptive bursts at 0150 UTC and 0435 UTC, August 8. Satellite data show a significant ash cloud associated with the 0435 UTC event followed by at least 14 hours of continuous ash emission. The lack of a strong ash signature in satellite data suggest that the first two plumes were ash poor. Satellite data also show a large emission of SO2 that entered the stratosphere. Correlation of eruptive periods with deposits on the island is not yet possible, but it appears that pyroclastic flows were emplaced during

  5. Preliminary volcano-hazard assessment for the Tanaga volcanic cluster, Tanaga Island, Alaska

    USGS Publications Warehouse

    Coombs, Michelle L.; McGimsey, Robert G.; Browne, Brandon L.

    2007-01-01

    Summary of Volcano Hazards at Tanaga Volcanic Cluster The Tanaga volcanic cluster lies on the northwest part of Tanaga Island, about 100 kilometers west of Adak, Alaska, and 2,025 kilometers southwest of Anchorage, Alaska. The cluster consists of three volcanoes-from west to east, they are Sajaka, Tanaga, and Takawangha. All three volcanoes have erupted in the last 1,000 years, producing lava flows and tephra (ash) deposits. A much less frequent, but potentially more hazardous phenomenon, is volcanic edifice collapse into the sea, which likely happens only on a timescale of every few thousands of years, at most. Parts of the volcanic bedrock near Takawangha have been altered by hydrothermal activity and are prone to slope failure, but such events only present a local hazard. Given the volcanic cluster's remote location, the primary hazard from the Tanaga volcanoes is airborne ash that could affect aircraft. In this report, we summarize the major volcanic hazards associated with the Tanaga volcanic cluster.

  6. Geophysical monitoring from seafloor observatories in Italian volcanic sites: Marsili Seamount, Etna Volcano and Stromboli Island.

    NASA Astrophysics Data System (ADS)

    Giovanetti, Gabriele; Monna, Stephen; Lo Bue, Nadia; Embriaco, Davide; Frugoni, Francesco; Marinaro, Giuditta; De Caro, Mariagrazia; Sgroi, Tiziana; Montuori, Caterina; De Santis, Angelo; Cianchini, Gianfranco; Favali, Paolo; Beranzoli, Laura

    2016-04-01

    Many volcanoes on Earth are located within or near the oceans and observations from the seafloor can be very important for a more complete understanding of the structure and nature of these volcanoes. We present some results obtained from data acquired in volcanic sites in the Central Mediterranean Sea. Data were taken by means of stand-alone free-fall systems, and fixed-point ocean observatories, both cabled and autonomous, some of which are part of the European research infrastructure EMSO (European Multidisciplinary Seafloor and water-column Observatory, www.emso-eu.org). EMSO observatories strongly rely on a multidisciplinary approach, in spite of the many technical challenges that the operation of very different sensors by means of a single acquisition system presents. We focus on three volcanic sites near the coasts of Italy (Marsili seamount, Stromboli Island and Etna Volcano) involved in subduction processes and to the opening of the Central Mediterranean basin. Through multidisciplinary analysis we were able to associate geophysical and oceanographic signals to a common volcanic source in a more reliable way with respect to single sensor analysis, showing the potential of long-term seafloor monitoring in unravelling otherwise still obscure aspects of such volcanoes. The very strong expansion of seafloor monitoring, which is taking place both in the quantity of the infrastructures and in the technological capabilities, suggests that there will be important developments in the near future.

  7. Active Volcanoes of the Kurile Islands: A Reference Guide for Aviation Users

    USGS Publications Warehouse

    Neal, Christina A.; Rybin, Alexander; Chibisova, Marina; Miller, Edward

    2008-01-01

    Introduction: The many volcanoes of the remote and mostly uninhabited Kurile Island arc (fig. 1; table 1) pose a serious hazard for air traffic in the North Pacific. Ash clouds from Kurile eruptions can impact some of the busiest air travel routes in the world and drift quickly into airspace managed by three countries: Russia, Japan, and the United States. Prevailing westerly winds throughout the region will most commonly send ash from any Kurile eruption directly across the parallel North Pacific airways between North America and Asia (Kristine A. Nelson, National Weather Service, oral commun., 2006; fig. 1). This report presents maps showing locations of the 36 most active Kurile volcanoes plotted on Operational Navigational Charts published by the Defense Mapping Agency (map sheets ONC F-10, F-11, and E-10; figs. 1, 2, 3, 4). These maps are intended to assist aviation and other users in the identification of restless Kurile volcanoes. A regional map is followed by three subsections of the Kurile volcanic arc (North, Central, South). Volcanoes and selected primary geographic features are labeled. All maps contain schematic versions of the principal air routes and selected air navigational fixes in this region.

  8. Discovery of an Active Submarine Mud Volcano Along the Nootka Fault West of Vancouver Island

    NASA Astrophysics Data System (ADS)

    Riedel, M.; Riedel, M.; Kelly, D. S.; Delaney, J. R.; Spence, G. D.; Hyndman, R. D.; Hyndman, R. D.; Mayer, L.; Calder, B.; Lilley, M. D.; Olson, E. O.; Schrenk, M. O.; Coffin, R.

    2001-12-01

    Submarine mud volcanoes are a common feature in margin environments, but few of them have been documented in the Northeast Pacific. However, during a Hydrosweep bathymetric survey in July, 2001, and a follow-on sub-surface seismic survey in August two mud volcanoes were imaged along the Nootka Fault, 16-18 km west of Vancouver Island at a water depth of 2500 m. The southern volcano, called Maquinna, lies directly along the southern expression of the left lateral, strike slip Nootka Fault. It is 1.5 km across, has a breached caldera and two small summit craters, and it stands about 30 m above the seafloor. The base is bounded by a narrow moat, partially filled by Holocene sediments that are flat lying; older, underlying sediments show steep downwarping towards the sides of the volcano. Subsurface imaging shows a dramatic loss of reflectivity beneath the volcano mound, which may indicate significant mobilization of material. However, a very bright reflector is seen at about 400 m depth below the volcano. This reflector is too deep for stability of methane clathrate, and is interpreted as a zone of high fluid content. A CTD vertical cast above the summit of the volcano showed strong, co-registered thermal, particulate, and oxygen anomalies that extend 50 m up into the overlying water column. These data indicate that the volcano is actively venting warm hydrothermal fluids. The fluids are depleted in CO2, contain background concentrations of CH4, but show elevated H2 concentrations above ocean background water. Microscopic examination of the Nootka hydrothermal samples shows that they contain dense and morphologically diverse microbial communities in comparison to background seawater with cell densities of 106 cells/ml. Enrichment culturing indicates that these communities include both anaerobic and aerobic organisms, some of which are thermophilic with optimal growth temperatures in excess of 50 deg C. Some of these cultures can use methane oxidation as an energy

  9. Enhanced syndromic surveillance for mass gatherings in the Pacific: a case study of the 11th Festival of Pacific Arts in Solomon Islands, 2012

    PubMed Central

    Hoy, Damian; Saketa, Salanieta T; Maraka, Roy Roger; Sio, Alison; Wanyeki, Ian; Frison, Pascal; Ogaoga, Divi; Iniakawala, Dennie; Joshua, Cynthia; Duituturaga, Sala; Lepers, Christelle; Roth, Adam; White, Paul; Souares, Yvan

    2016-01-01

    Mass gatherings pose public health challenges to host countries, as they can cause or exacerbate disease outbreaks within the host location or elsewhere. In July 2012, the 11th Festival of Pacific Arts (FOPA), a mass gathering event involving 22 Pacific island states and territories, was hosted by Solomon Islands. An enhanced syndromic surveillance (ESS) system was implemented for the event. Throughout the capital city, Honiara, 15 sentinel sites were established and successfully took part in the ESS system, which commenced one week before the FOPA (25 June) and concluded eight days after the event (22 July). The ESS involved expanding on the existing syndromic surveillance parameters: from one to 15 sentinel sites, from four to eight syndromes, from aggregated to case-based reporting and from weekly to daily reporting. A web-based system was developed to enable data entry, data storage and data analysis. Towards the end of the ESS period, a focus group discussion and series of key informant interviews were conducted. The ESS was considered a success and played an important role in the early detection of possible outbreaks. For the period of the ESS, 1668 patients with syndrome presentations were received across the 15 sentinel sites. There were no major events of public health significance. Several lessons were learnt that are relevant to ESS in mass gathering scenarios, including the importance of having adequate lead in time for engagement and preparation to ensure appropriate policy and institutional frameworks are put in place. PMID:27766181

  10. The western Aeolian Islands volcanoes (South Tyrrhenian Sea): highlight on their eruptive history based on K-Ar dating.

    NASA Astrophysics Data System (ADS)

    Leocat, E.; Gillot, P.-Y.; Peccerillo, A.

    2012-04-01

    The Aeolian Islands volcanoes are located in southern Tyrrhenian Sea on the northern continental margin of the Calabro-Peloritan basement. The Stromboli, Panarea and Vulcano volcanoes of the half eastern sector are well studied as they are still active and they represent high volcanic hazard. While stratigraphic studies were carried out on volcanoes of the western sector, radiometric ages are lacking to well understand their eruptive history. Therefore, new geochronological and geochemical data were obtained for Alicudi, Filicudi, Salina and Lipari western volcanoes. The aim is to establish a complete time framework of the volcanism and to study possible time-related variations of magma compositions. The 37 new ages were obtained using K-Ar Cassignol-Gillot technique that is suitable for dating Quaternary volcanic rocks. The new geochemical data consist of whole rock major and trace elements analysis on dated samples. Our new sets of data give evidence that the Aeolian Islands are young volcanoes emplaced within the last 300 ka. The oldest products outcrop at Filicudi, Salina and Lipari. Te first emerged activity of Alicudi volcano occurred 120 ka ago. While quiescence activity of at least 50 ka is recognized at Filicudi and Lipari, and potentially at Salina, the volcanic activity of Alicudi would have been relatively continuous. These whole volcanoes were active within the last 30 ka which has to be considered for volcanic hazard assessment. At the scale of each volcano, the degree of differentiation increase roughly through time, except at Filicudi where the ultimate products correspond to mafic magma. At the scale of the archipelago, this process increases from western Alicudi and Filicudi volcanoes, where andesitic magmas are the most evolved magmas, to central Salina and Lipari volcanoes, where rhyolitic magmas are emitted during explosive eruption. Moreover, pulses of magmatic activity would have occurred around 30-40 and 110-120 ka when the four volcanoes

  11. Ocean noise triggering of rhythmic long period events at Deception Island volcano

    NASA Astrophysics Data System (ADS)

    Stich, Daniel; Almendros, Javier; Jiménez, Vanessa; Mancilla, Flor; Carmona, Enrique

    2011-11-01

    We report on swarms of repeating long-period (LP) events with remarkably periodic occurrence at Deception Island volcano, Antarctica. The LP events show dominant frequencies near 2 Hz and characteristic inter-event times that range from ˜10 s to ˜20 s for individual swarms. We observe that LP inter-event times are approximate integer multiples of the dominant periods of the oceanic microseism, indicating a synchronization of LP activity with the phase of ocean noise. We attribute LP periodicity to the coincidence of sustained LP activity in an unstable hydrothermal system and external forcing by ocean noise that introduces periodic pressure variations in volcano fluids. We estimate the volumetric strain change generated by the oceanic microseism at the source location and conclude that strain of order 10-7 is sufficient to introduce clear periodicity in the LP sequences, and that periodicity increases with increasing strain.

  12. Long-distance lateral magma transport from intra-oceanic island arc volcanoes

    NASA Astrophysics Data System (ADS)

    Ishizuka, O.; Geshi, N.; Kawanabe, Y.; Ogitsu, I.; Tuzino, T.; Nakano, S.; Arai, K.; Sakamoto, I.; Taylor, R. N.; Sano, K.; Yamamoto, T.

    2011-12-01

    Long-distance lateral magma transport in oceanic island arc volcanoes is emerging as a common phenomenon where the regional stress regime is favorable. It should also be recognized as an important factor in the construction and growth of island arcs. In this contribution, we report on recent investigations into the magma plumbing of Izu-Oshima volcano: an active basaltic volcano with an extensive fissure system. Geophysical observations in the Izu-Bonin intra-oceanic island arc indicate that magma is transported long distances laterally from the main basaltic composite volcano. When Miyakejima erupted in 2000, seismic activity migrated about 30km northwestward from the volcanic centre (Geshi et al., 2002). This event is interpreted to reflect northwestward dike injection and propagation from Miyakejima, transporting magma at a depth range between 12 and 20km (Kodaira et al., 2002). We demonstrated that long-distance lateral magma transport also occurred at the Nishiyama volcano on Hachijojima Island using petrological, geochemical and structural studies of satellite vents (Ishizuka et al., 2008). Nishiyama provided evidence for two types of magma transport. In the first type, primitive magma moved laterally NNW for at least 20km in the middle to lower crust (10-20km deep). The other type is characterized by magmas that have experienced differentiation in a shallow magma chamber beneath Nishiyama and have been transported short distances (<5km). The long-distance magma transport seems to be controlled by a regional extensional stress regime, while short distance transport may be controlled by local stress regime affected by the load generated by the main volcanic edifice. Izu-Oshima volcano comprises numerous, subparallel NW-SE trending submarine ridges extending up to 22 km to the NW and SE from the summit of Izu-Oshima. A recent diving survey has revealed that: 1) NW-SE trending ridges are fissures which erupted basaltic spatter and lava flows. 2) Basaltic

  13. Volcano-hydrothermal system of Ebeko volcano, Paramushir, Kuril Islands: Geochemistry and solute fluxes of magmatic chlorine and sulfur

    NASA Astrophysics Data System (ADS)

    Kalacheva, Elena; Taran, Yuri; Kotenko, Tatiana; Hattori, Keiko; Kotenko, Leonid; Solis-Pichardo, Gabriela

    2016-01-01

    Ebeko volcano at the northern part of Paramushir Island in the Kuril island arc produces frequent phreatic eruptions and relatively strong fumarolic activity at the summit area ~ 1000 m above sea level (asl). The fumaroles are characterized by low-temperature, HCl- and S-rich gas and numerous hyper-acid pools (pH < 1) without drains. At ~ 550 m asl, in the Yurieva stream canyon, many hot (up to 87 °C) springs discharge ultra-acidic (pH 1-2) SO4-Cl water into the stream and finally into the Sea of Okhotsk. During quiescent stages of degassing, these fumaroles emit 1000-2000 t/d of water vapor, < 20 t/d of SO2 and < 5 t/d of HCl. The measurement of acidic hot Yurieva springs shows that the flux of Cl and S, 60-80 t/d each, is independent on the volcanic activity in the last two decades. Such high flux of Cl is among the highest ever measured in a volcano-hydrothermal system. Oxygen and hydrogen isotopic composition of water and Cl concentration for Yurieva springs show an excellent positive correlation, indicating a mixing between meteoric water and magmatic vapor. In contrast, volcanic gas condensates of Ebeko fumaroles do not show a simple mixing trend but rather a complicated data suggesting evaporation of the acidic brine. Temperatures calculated from gas compositions and isotope data are similar, ranging from 150 to 250 °C, which is consistent with the presence of a liquid aquifer below the Ebeko fumarolic fields. Saturation indices of non-silicate minerals suggest temperatures ranging from 150 to 200 °C for Yurieva springs. Trace elements (including REE) and Sr isotope composition suggest congruent dissolution of the Ebeko volcanic rocks by acidic waters. Waters of Yurieva springs and waters of the summit thermal fields (including volcanic gas condensates) are different in Cl/SO4 ratios and isotopic compositions, suggesting complicated boiling-condensation-mixing processes.

  14. What drives centuries-long polygenetic scoria cone activity at Barren Island volcano?

    NASA Astrophysics Data System (ADS)

    Sheth, Hetu

    2014-12-01

    Barren Island in the Andaman Sea is an active mafic stratovolcano, which had explosive and effusive eruptions, followed by caldera formation, in prehistoric time (poorly dated). A scoria cone within the caldera, marking volcanic resurgence, was active periodically from 1787 to 1832 (the historic eruptions). Since 1991, the same scoria cone has produced six eruptions, commonly including lava flows. Links between Barren Island's eruptions and giant earthquakes (such as the 26 December 2004 Great Sumatra megathrust earthquake) have been suggested, though there is no general correlation between them. The ≥ 227-year-long activity of the scoria cone, named here Shanku ("cone"), is normally driven by purely magmatic processes. I present a "source to surface" model for Barren Island and Shanku, including the source region, deeper and shallow magma chambers, volcanotectonics, dyking from magma chambers, and eruptions and eruptive style as controlled by crustal stresses, composition and volatile content. Calculations show that dykes ~ 0.5 m thick and a few hundred meters long, originating from shallow-level magma chambers (~ 5 km deep), are suitable feeders of the Shanku eruptions. Shanku, a polygenetic scoria cone (at least 13 eruptions since 1787), has three excellent analogues, namely Anak Krakatau (40 eruptions since 1927), Cerro Negro (23 eruptions since 1850), and Yasur (persistent activity for the past hundreds of years). This is an important category of volcanoes, gradational between small "monogenetic" scoria cones and larger "polygenetic" volcanoes.

  15. Influence of environmental factors on the abundance of Anopheles farauti larvae in large brackish water streams in Northern Guadalcanal, Solomon Islands

    PubMed Central

    2011-01-01

    Background The main vector of malaria in Solomon Islands is Anopheles farauti, which has a mainly coastal distribution. In Northern Guadalcanal, Solomon Islands, high densities of An. farauti are supported by large brackish streams, which in the dry season are dammed by localized sand migration. The factors controlling the high larval productivity of these breeding sites have not been identified. Accordingly the influence of environmental factors on the presence and density of An. farauti larvae was assessed in three large naturally dammed streams. Methods Larval sites were mapped and anopheline larvae were collected monthly for 12 months (July 2007 to June 2008) from three streams using standard dippers. Larval collections were made from 10 locations spaced at 50 m intervals along the edge of each stream starting from the coast. At each collection point, floating filamentous algae, aquatic emergent plants, sun exposure, and salinity were measured. These environmental parameters along with rainfall were correlated with larval presence and density. Results The presence and abundance of An. farauti larvae varied between streams and was influenced by the month of collection, and distance from the ocean (p < 0.001). Larvae were more frequently present and more abundant within 50 m of the ocean during the dry season when the streams were dammed. The presence and density of larvae were positively associated with aquatic emergent plants (presence: p = 0.049; density: p = 0.001). Although filamentous algae did not influence the presence of larvae, this factor did significantly influence the density of larvae (p < 0.001). Rainfall for the month prior to sampling was negatively associated with both larval presence and abundance (p < 0.001), as high rainfall flushed larvae from the streams. Salinity significantly influenced both the presence (p = 0.002) and density (p = 0.014) of larvae, with larvae being most present and abundant in brackish water at < 10‰ seawater

  16. Interaction between forest biodiversity and people’s use of forest resources in Roviana, Solomon Islands: implications for biocultural conservation under socioeconomic changes

    PubMed Central

    2014-01-01

    Background In Solomon Islands, forests have provided people with ecological services while being affected by human use and protection. This study used a quantitative ethnobotanical analysis to explore the society–forest interaction and its transformation in Roviana, Solomon Islands. We compared local plant and land uses between a rural village and urbanized village. Special attention was paid to how local people depend on biodiversity and how traditional human modifications of forest contribute to biodiversity conservation. Methods After defining locally recognized land-use classes, vegetation surveys were conducted in seven forest classes. For detailed observations of daily plant uses, 15 and 17 households were randomly selected in the rural and urban villages, respectively. We quantitatively documented the plant species that were used as food, medicine, building materials, and tools. Results The vegetation survey revealed that each local forest class represented a different vegetative community with relatively low similarity between communities. Although commercial logging operations and agriculture were both prohibited in the customary nature reserve, local people were allowed to cut down trees for their personal use and to take several types of non-timber forest products. Useful trees were found at high frequencies in the barrier island’s primary forest (68.4%) and the main island’s reserve (68.3%). Various useful tree species were found only in the reserve forest and seldom available in the urban village. In the rural village, customary governance and control over the use of forest resources by the local people still functioned. Conclusions Human modifications of the forest created unique vegetation communities, thus increasing biodiversity overall. Each type of forest had different species that varied in their levels of importance to the local subsistence lifestyle, and the villagers’ behaviors, such as respect for forest reserves and the

  17. Man against volcano: The eruption on Heimaey, Vestmann Islands, Iceland

    USGS Publications Warehouse

    Williams, R.S.; Moore, J.G.

    1976-01-01

    The U.S. Geological Survey carries out scientific studies in the geological, hydrological, and cartographic sciences generally within the 50 states, but also in cooperation with scientific organizations in many foreign countries for the investigation of unusual earth science phenomena throughout the world. The following material discusses the impact of the 1973 volcanic eruption of Eldfell on the fishing port of Vestmannaeyjar on the island of Heimaey, Iceland. Before the eruption was over, approximately one-third of the town of Vestmannaeyjar had been obliterated but, more importantly, the potential damage had been reduced markedly by the spraying of seawater onto the advancing lava flows, causing them to be slowed, stopped, or diverted from the undamaged portion of the town. The Survey's interest and involvement in the Heimaey eruption in Iceland was occasioned by the possibility that the procedures used to control the course of the flowing lava and to reduce the damage in a modern town may some day be needed in Hawaii and possibly even in the continental United States. This publication is based on the observations of two USGS geologists, Richard S. Williams, Jr. and James G. Moore, as well as on information from the Icelandic Ministry for Foreign Affairs, Icelandic scientists' reports through the Center for Short-Lived Phenomena, and other published scientific reports. A number of Icelandic scientists studied the scientific aspects of the eruption and the engineering aspects of the control of lava flows, in particular, Professors Thorbjb'rn Sigurgeirsson and Sigurdur Thorarinsson of the University of Iceland Science Institute. Also, Icelandic governmental officials provided logistical and other support, in particular, Mr. Steingnmur Hermannsson, Director, Icelandic National Research Council and Professor Magnus Magnusson, Director, University of Iceland Science Institute.

  18. Eruption of soufriere volcano on st. Vincent island, 1971-1972.

    PubMed

    Aspinall, W P; Sigurdsson, H; Shepherd, J B

    1973-07-13

    The Soufrière volcano in St. Vincent erupted from October 1971 to March 1972, as 80 x 10(6) m(3) of basaltic andesite lava was quietly extruded inside the mile-wide crater. The eruption was largely subaqueous, taking place in the 180-m-deep crater lake, and resulted in the emergence of a steep-sided island. The mild character of the eruption and the absence of seismic activity stand in direct contrast to the highly explosive character of the eruption of 1902 to 1903.

  19. Eruption of soufriere volcano on st. Vincent island, 1971-1972.

    PubMed

    Aspinall, W P; Sigurdsson, H; Shepherd, J B

    1973-07-13

    The Soufrière volcano in St. Vincent erupted from October 1971 to March 1972, as 80 x 10(6) m(3) of basaltic andesite lava was quietly extruded inside the mile-wide crater. The eruption was largely subaqueous, taking place in the 180-m-deep crater lake, and resulted in the emergence of a steep-sided island. The mild character of the eruption and the absence of seismic activity stand in direct contrast to the highly explosive character of the eruption of 1902 to 1903. PMID:17746610

  20. Youth research. Naked wire and naked truths: a study of reproductive health risks faced by teenage girls in Honiara, Solomon Islands, November 1997.

    PubMed

    1998-01-01

    A qualitative research project conducted in 1997 in the Solomon Islands used questionnaires, focus groups discussions, and in-depth interviews to gather information on reproductive health risks faced by young, unmarried women in Honiara. In this setting, urbanization and poverty, migration, unemployment, and low levels of education increase the risk for youth of acquiring HIV/AIDS or a sexually transmitted disease (STD). Young women, who must yield to the authority of their male relatives, often have clandestine sexual relationships beginning as early as age 12 and are unable to negotiate safe sex behavior. Commercial sexual exchanges are also on the increase. Sex education is generally confined to secondary schools, although most girls drop-out after primary school. The main source of sex information is the media and friends. While there is concern about adolescent pregnancy rates, contraceptive access is restricted to young, unmarried women. The reaction of a family to an adolescent pregnancy is initial anger and ultimate acceptance. Condom use is low, largely because it is believed that it interferes with sexual pleasure. Because the young women are unable to negotiate safe sex, they are at risk of pregnancy, STDs, and HIV/AIDS. The situation can be improved by creating an enabling environment for young women through policy initiatives, improving knowledge, promoting condom use, providing reproductive health services, and improving communication channels.

  1. Evidence for Late Eocene emplacement of the Malaita Terrane, Solomon Islands: Implications for an even larger Ontong Java Nui oceanic plateau

    NASA Astrophysics Data System (ADS)

    Musgrave, Robert J.

    2013-06-01

    Most tectonic models for the Solomon Islands Arc invoke a Miocene collision with the Ontong Java Plateau (OJP) to halt cessation of Pacific Plate subduction, initiate Australian Plate subduction, and emplace the Malaita Terrane, which shares the characteristic basement age and geochemistry of OJP. Existing paleomagnetic evidence, however, required the Malaita Terrane to have been fixed to the arc from at least the Late Eocene. New sampling has yielded a paleomagnetic pole from Aptian-Albian limestones and mudstones that falls between the apparent polar wander paths for the Australian Plate and OJP, confirming the extended period of residence of the Malaita Terrane on the arc. Arc-derived turbidities within Late Eocene through Miocene limestones on Malaita and Santa Isabel, and related clasts in broadly contemporary sandstones and conglomerates on Santa Isabel, also attest to early emplacement. Modeling the emplacement at 35 Ma satisfies both the paleomagnetic data and the sediment provenance. Continuing the reconstruction to 125 Ma leaves the Malaita Terrane far from OJP at the time of plateau formation. OJP is now understood to have formed as part of a larger Ontong Java Nui, also comprising the Hikurangi and Manihiki plateaus, separated by spreading during the Cretaceous. Restoring the separation of the known elements, and invoking an additional triple junction, unites the (now largely subducted) Malaita Terrane with the rest of Ontong Java Nui. Subduction of substantial areas of the Ontong Java Nui plateau, with little geological signal other than a reduction in arc volcanism, is a corollary.

  2. Modernization and the onset of overweight and obesity in Bougainville and Solomon Islands children: cross-sectional and longitudinal comparisons between 1966 and 1986.

    PubMed

    Weitz, Charles A; Friedlaender, Françoise R; Van Horn, Andrew; Friedlaender, Jonathan S

    2012-11-01

    This set of cross-sectional and longitudinal data from children and young adults in certain Bougainville and Solomon Islands populations undergoing rapid modernization during the period 1966-1986 reveals very different responses to essentially the same stimuli-the introduction and widespread availability of western dietary items and reductions in habitual activity. Our analyses of over 2,000 children and young adults first measured in 1966-1972, with follow-up surveys in 1968-1970 and 1985-1986, show changes in overweight/obesity in these communities have their onset around puberty, and are not related to differences in childhood growth stunting. The prevalence of overweight and obesity increased substantially during the period of this study among young adults, particularly women, and in groups with more Polynesian affinities, where the frequency of overweight (BMI ≥ 25) tripled over this 20-year interval. However, the BMI of the more Papuan groups on Bougainville remained remarkably stable, even though they were close to the epicenter of modernization during this period, the Bougainville Copper Mine. PMID:23042600

  3. Elements of Pacific public health laws: an analysis of the public health acts of Papua New Guinea, Vanuatu, the Solomon Islands, and Fiji.

    PubMed

    Howse, Genevieve

    2012-09-01

    Pacific countries are sovereign nations with distinctive histories, ethnicity, customs, primary resources, economies, and health systems. Despite these and other acknowledged differences, similarities exist in many areas such as geography, legal history, and culture. Many share the experience of colonization, with imported British laws and the subsequent experience of independence. Most Pacific countries are also developing countries. This article broadly describes approaches to legislating in public health in Papua New Guinea, Fiji, Vanuatu, and the Solomon Islands and notes common elements in their public health laws, in particular, in relation to administration, allocation of powers and responsibilities, interaction with local government, communicable disease control, and nuisance. The article concludes that many Pacific public health laws could deliver better support for current health policy, more sensitivity to the culture and customs of the region, and better management of public health risk through laws that are better suited to their Pacific environment, easier to understand, more flexible, and more relevant to current health policy. PMID:23093516

  4. Effect of Diel Activity Patterns and Harvesting Pressure on the Diversity and Biomass of Sea Cucumbers in Marovo Lagoon, Solomon Islands

    NASA Astrophysics Data System (ADS)

    Buckius, Christine; Albert, Simon; Tibbetts, Ian; Udy, James

    2010-05-01

    A marked decline in the contribution by Marovo Lagoon to the annual total bêche-de-mer production of the Solomon Islands from 58% in 1989 to 17% in 2003 prompted investigation of their current biomass and diversity. We also assessed changes to critical ecological services and the prospects for population recovery following a fisheries closure. Day time and nocturnal transects revealed a mean abundance of 32.4 (SD = 5.3) low value species per ha (e.g. Holothuria atra, H. edulis, H. coluber and Thelenota anax) and 15.2 (SD = 2.7) high value species per ha (e.g. H. fuscogilva, Actinopyga lecanora, Stichopus hermanni and Thelenota ananas). Following a 17 month closure of the fishery (2005-2007), the abundance of bêche-de-mer was reported by local fisherman to have increased; however, no scientific studies were conducted that can substantiate this community held belief. The current study aimed to document the impact of re-opening the fishery in 2007 and documented a decline in high value species of 9% over a 5 month period following the opening of the fishery, while low value species continued to increase in abundance by 11%, over the same period based on nocturnal surveys. Continued observation of the recovery, post closure, and any subsequent harvest in Marovo will be required to properly understand population dynamics and provide a sustainable harvest plan for bêche-de-mer in the future.

  5. Estimated pressure source on Kozu Island volcano, South Central Japan, from GPS measurements (July 1996-August 1999)

    NASA Astrophysics Data System (ADS)

    Kimata, Fumiaki; Kariya, Shin-ichi; Fujita, Masayuki; Matsumoto, Kunio; Tabei, Takao; Segawa, Jiro; Yamada, Akiko

    2000-11-01

    Although the Kozu Island Volcano, one of the Izu Islands Volcanoes in the south part Central Japan, is an active volcano, there is no record of the eruption for about 1100 years since the last eruption in 833 A.D. Since 1988, frequent earthquake swarms are observed around the Kozu Island, and the uplift of 2-4 cm/yr is observed on the island by tidal observations. Station velocities detected by GPS measurements since 1989 show velocities that differ from the convergent velocity of the Philippine Sea plate calculated from plate motion models. A local GPS network with 12 stations is occupied around the volcano, and the GPS measurements are repeated every about six month since July 1996. Inflated deformation of 2-4 cm/yr are detected from the GPS measurements and the pressure source is estimated to be located in the northeastern part of the island at a depth of 2.1 km using Mogi solution. Negative gravity changes of more than 30 microgal are also measured above the pressure source in the period November 1998 to July 1999, consistent with uplift.

  6. Environmental monitoring of El Hierro Island submarine volcano, by combining low and high resolution satellite imagery

    NASA Astrophysics Data System (ADS)

    Eugenio, F.; Martin, J.; Marcello, J.; Fraile-Nuez, E.

    2014-06-01

    El Hierro Island, located at the Canary Islands Archipelago in the Atlantic coast of North Africa, has been rocked by thousands of tremors and earthquakes since July 2011. Finally, an underwater volcanic eruption started 300 m below sea level on October 10, 2011. Since then, regular multidisciplinary monitoring has been carried out in order to quantify the environmental impacts caused by the submarine eruption. Thanks to this natural tracer release, multisensorial satellite imagery obtained from MODIS and MERIS sensors have been processed to monitor the volcano activity and to provide information on the concentration of biological, chemical and physical marine parameters. Specifically, low resolution satellite estimations of optimal diffuse attenuation coefficient (Kd) and chlorophyll-a (Chl-a) concentration under these abnormal conditions have been assessed. These remote sensing data have played a fundamental role during field campaigns guiding the oceanographic vessel to the appropriate sampling areas. In addition, to analyze El Hierro submarine volcano area, WorldView-2 high resolution satellite spectral bands were atmospherically and deglinted processed prior to obtain a high-resolution optimal diffuse attenuation coefficient model. This novel algorithm was developed using a matchup data set with MERIS and MODIS data, in situ transmittances measurements and a seawater radiative transfer model. Multisensor and multitemporal imagery processed from satellite remote sensing sensors have demonstrated to be a powerful tool for monitoring the submarine volcanic activities, such as discolored seawater, floating material and volcanic plume, having shown the capabilities to improve the understanding of submarine volcanic processes.

  7. Toward a three-century reconstruction of climate variability from a slow-growing coral in the Western Province, Solomon Islands

    NASA Astrophysics Data System (ADS)

    Maupin, C. R.; Quinn, T. M.; Taylor, F. W.; lin, K.; Shen, C.

    2012-12-01

    Climate variability in the west Pacific warm pool (WPWP), a major heat and moisture source to the atmosphere, is strongly influenced by the El Niño-Southern Oscillation (ENSO). Modeling work has suggested that multi-century scale reconstructions of ENSO variability from the tropical west Pacific may be necessary to fully characterize the nature of the ENSO system. Much of the previous coral-based climate studies have used the fast-growing coral genus Porites, although a few studies have used the long-lived, slow-growing coral genus Diploastrea. Here we present an oxygen isotope time series from a three century long D. heliopora coral from near Olasana Island, Western Province, Solomon Islands (WPSI, 8°07.92' S, 156°54.50' E), a location in the WPWP that experiences significant temperature and salinity anomalies during ENSO events. We first used a forward model to generate a pseudoproxy time series for the Olasana region, utilizing available gridded sea surface temperature (SST) and sea surface salinity (SSS) data spanning 1970-2007. There are strong correlations between predicted and measured coral δ18O, between both monthly (r = 0.84) and monthly anomaly (r = 0.69) records. These results demonstrate that the Olasana D. heliopora coral δ18O record is a robust proxy of local surface ocean conditions. There is also a robust relationship between the Olasana δ18O record and NINO3.4 index of ENSO activity during 1938-2007, which provides confidence that the Olasana δ18O record can be used to characterize the ENSO state in this region back in time. Finally, we present results from near the core bottom (~1700 CE), which provide a first window into a gap of coral-based ENSO reconstructions in the immediate preindustrial (~1700-1850 CE).

  8. Using volcanic tremor for eruption forecasting at White Island volcano (Whakaari), New Zealand

    NASA Astrophysics Data System (ADS)

    Chardot, Lauriane; Jolly, Arthur D.; M. Kennedy, Ben; Fournier, Nicolas; Sherburn, Steven

    2015-09-01

    Eruption forecasting is a challenging task because of the inherent complexity of volcanic systems. Despite remarkable efforts to develop complex models in order to explain volcanic processes prior to eruptions, the material Failure Forecast Method (FFM) is one of the very few techniques that can provide a forecast time for an eruption. However, the method requires testing and automation before being used as a real-time eruption forecasting tool at a volcano. We developed an automatic algorithm to issue forecasts from volcanic tremor increase episodes recorded by Real-time Seismic Amplitude Measurement (RSAM) at one station and optimised this algorithm for the period August 2011-January 2014 which comprises the recent unrest period at White Island volcano (Whakaari), New Zealand. A detailed residual analysis was paramount to select the most appropriate model explaining the RSAM time evolutions. In a hindsight simulation, four out of the five small eruptions reported during this period occurred within a failure window forecast by our optimised algorithm and the probability of an eruption on a day within a failure window was 0.21, which is 37 times higher than the probability of having an eruption on any day during the same period (0.0057). Moreover, the forecasts were issued prior to the eruptions by a few hours which is important from an emergency management point of view. Whereas the RSAM time evolutions preceding these four eruptions have a similar goodness-of-fit with the FFM, their spectral characteristics are different. The duration-amplitude distributions of the precursory tremor episodes support the hypothesis that several processes were likely occurring prior to these eruptions. We propose that slow rock failure and fluid flow processes are plausible candidates for the tremor source of these episodes. This hindsight exercise can be useful for future real-time implementation of the FFM at White Island. A similar methodology could also be tested at other

  9. Forearc Structure and Fault Slip Near the Epicenter of the April 1, 2007, Megathrust Earthquake (Mw 8.1) and Tsunami in the Solomon Islands

    NASA Astrophysics Data System (ADS)

    Fisher, M. A.; Scholl, D. W.; Geist, E. L.; Sliter, R. W.; Wong, F. L.; Reiss, C.; Mann, D. M.

    2007-12-01

    We reprocessed three multichannel seismic-reflection (MCS) lines collected by the USGS (1982, 1984) near the epicenter of the 2007 Mw-8.1 megathrust earthquake that struck the Solomon Islands. Near the epicenter, several bathymetric and tectonic elements, including an active spreading ridge and a transform fault, are being subducted at the New Britain Trench. These subducted elements affected fault slip during the earthquake, as indicated by two finite fault models (Yagi, 2007; Ji, 2007). Slip began around the epicenter, southeast of where the spreading ridge enters the subduction zone. Slip was reduced directly over the ridge, and northwest of the ridge, slip resumed with increased, possibly maximum amplitude. Fault rupture propagated northwestward at about 1.95 km/s (Yagi, 2007). The Woodlark spreading ridge, with its irregular bathymetry and probable high heat flow, injects a strong three-dimensionality into the analysis of fault slip along the interplate thrust. MCS data show smooth reflections from the interplate decollement that can be followed for about 40 km east of the trench, and hypocenters locally recorded during 1998 (Yoneshima et al., 2005) trace the plate interface deep into the subduction zone. The downgoing plate dips ~30° northeast through the zone of highest 1998 seismic activity, which occurs below 20 km depth. Although young oceanic crust is being subducted eastward along the New Britain Trench, the subducting plate bends sharply downward and dips steeply (30° to 45°) into the mantle. Teleseismic data place the 2007 earthquake epicenter near the trench axis, close to the up-dip limit of the seismogenic zone indicated by the 1998 seismicity. Under the upper slope of the island arc south of the epicenter, strong reflections suggest a mixed volcanic and carbonate-rock framework of the island arc. Down slope of where the strong reflections end, seaward-verging thrust faults deform several small forearc basins. Deformation occurred episodically

  10. Radon-222 from the island of hawaii: deep soils are more important than lava fields or volcanoes.

    PubMed

    Wilkening, M H

    1974-02-01

    The mean flux of radon-222 atoms from the island of Hawaii is 0.45 atom per square centimeter per second. Lava fields occupy 50 percent of the land area, but their radon flux is only 1 percent of that from deep volcanic soils. The island yields approximately 10 curies of radon-222 per hour to the air surrounding it. The radon-222 contribuition of volcanoes is negligible.

  11. Magma Genesis of Sakurajima, the Quaternary post- Aira caldera volcano, southern Kyushu Island, Japan

    NASA Astrophysics Data System (ADS)

    Shibata, T.; Suzuki, J.; Yoshikawa, M.; Kobayashi, T.; Miki, D.; Takemura, K.

    2012-12-01

    Sakurajima volcano is the Quaternary post-caldera volcano of Aira caldera, which was caused by the eruption of huge amount of silicic pyroclastics, situated on Ryukyu arc, southern Kyushu Island, Japan. This volcano is quite active, so it can be considered that the preparation of next caldera-forming eruption with huge amount of silicic magma is proceeding. It is, therefore, expected that the investigation of magma genesis of Sakurajima volcano give us information for the mechanism generating huge amount of silicic magma, which cause the caldera formation. We analyzed major and trace elements with Sr, Nd and Pb isotopic compositions of volcanic rocks from Sakurajima volcano. We sampled (ol) - opx - cpx - pl andesite and dacite from almost all the volcanic units defined by Fukuyama and Ono (1981). In addition to Sakurajima samples, we also studied basaltic rocks erupted at pre-caldera stage of the Aira caldera to estimate the primary magma of Sakurajima volcano. Major and trace element variations generally show linear trends on the Harker diagrams, with the exception of P2O5 and TiO2. Based on the trend of P2O5 vs.SiO2, we divided studied samples low-P (P2O5 < 0.15 wt. %) and high-P (P2O5 > 0.15 wt. %) groups and these groups also display two distinct trends on TiO2-SiO2 diagram. The composition of trace elements shows typical island arc character as depletion of Nb and enrichments of Rb, K and Pb, suggesting addition of aqueous fluids to the mantle wedge. The Zr and Nb concentrations make a liner trend (Zr/Nb = 27) and this trend across from tend of MORB (Zr/Nb = 35) to that of crustal materials (Zr/Nb=17). The Sr, Nd and Pb isotopic compositions broadly plot to on the mixing curve connecting MORB-type mantle and sediments of the Philippine Sea Plate, indicating that the primary magma was generated by partial melting of MORB-type mantle wedge, which was hydrated with fluids derived from the subducted Philippine Sea sediments. But we found that our data plot apart

  12. Evolution and facies architecture of Paleogene Surtseyan volcanoes on Chatham Islands, New Zealand, Southwest Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Sorrentino, Leonor; Cas, Ray A. F.; Stilwell, Jeffrey D.

    2011-04-01

    This paper reports for the first time phreatomagmatic deposits and preserved Surtseyan tuff cones in the Chatham Islands, New Zealand. Fieldwork has located the relicts of at least six, closely-spaced, Paleogene Surtseyan-cones and associated volcaniclastic sediments within the Red Bluff Tuff Formation. The complete stratigraphic section of the cones consists of two parts: 1) the lower part represents volcanic aggradational processes that constructed tuff cones in a short period of time, and is composed of a bedded interval of explosively fragmented, vesicular glassy basaltic pyroclasts (ash and lapilli sizes) as well as feeder-dykes, pillow-lavas and pillow-sills and 2) the upper part represents the rapid denudation of these cones by shallow marine currents or gravity-flows reflecting the instability of the tephra-pile forming the cones, and a much later marine faunal colonization stage (e.g. corals, brachiopods, molluscs, etc.). Erosion could have occurred almost immediately after (or even during) the emplacement of the volcanic pile, similar to what occurred at Surtla vent, a satellite submerged cone of the basaltic island volcano Surtsey, Iceland; the Waiareka-Deborah Volcanics Bridge Point, Aorere Point, and Lookout Bluff Surtseyan-cones (Otago, New Zealand); and Marion and Prince Edward islands (Southwest Indian Ocean), amongst others. By contrast, the complete faunal colonization and stabilization of a diverse marine community could have taken hundreds, or perhaps even thousands of years to reach their acme following the volcanic pulses. The structural, textural and compositional characteristics of the Red Bluff Tuff Formation support a phreatomagmatic mode of fragmentation similar to that at Surtsey Volcano, Iceland. The Red Bluff Tuff sequence represents one of the most complete marine tuff cones described in the geologic record.

  13. The eruption of Mount Pagan volcano, Mariana Islands, 15 May 1981

    NASA Astrophysics Data System (ADS)

    Banks, Norman G.; Koyanagi, Robert Y.; Sinton, John M.; Honma, Kenneth T.

    1984-10-01

    A major explosive eruption occurred 15 May 1981 at Mount Pagan Volcano, the larger of two historic eruptive centers on Pagan Island, Mariana Islands. The eruption was preceded by increased numbers of locally felt earthquakes beginning in late March or early April and by new ground cracks, new sublimates, and increased gas emissions. A swarm of felt earthquakes began at 0745h (local time = UCT+10 hours) 15 May, and at 0915 h, closely following a loud sonic boom, a strong plinian column issued from the volcano. The high-altitude ash cloud (at least 13.5 km) travelled south-southeast, but ash and scoria deposits were thickest (> 2 m) in the NW sector of the island because of the prevailing low-altitude southeasterly winds. The early activity of 15 May probably involved magmatic eruption along a fissure system oriented about N10°E. However, the eruption became hydromagmatic, possibly within minutes, and was largely restricted to three long-lived vents. The northernmost of these built a substantial new scoria-ash cinder cone. Flows and air-fall deposits, consisting almost entirely of juvenile material, exceeded 105 × 10 6 m 3 in volume (75 × 10 6 m 3 of magma) on land and at least 70-100 × 60 6 m 3 at sea. An unknown volume was carried away by stratospheric winds. Lithic blocks and juvenile bombs as large as 1 m in diameter were thrown more than 2 km from the summit, and evidence for base-surge was observed in restricted corridors as low as 200 m elevation on the north and south slopes of the volcano. Neither of these events resulted in serious injuries to the 54 residents of the island, nor did the eruption produce serious chemical hazards in their water supply. Weak eruptions occurred during the ensuing month, and some of these were monitored by ground observations, seismic monitoring, and deformation studies. Precursory seismicity and possibly deformation occurred with some of the observed eruptions. More vigorous eruptions were reported by visiting residents in

  14. The eruption of Mount Pagan volcano, Mariana Islands, 15 May 1981

    USGS Publications Warehouse

    Banks, N.G.; Koyanagi, R.Y.; Sinton, J.M.; Honma, K.T.

    1984-01-01

    A major explosive eruption occurred 15 May 1981 at Mount Pagan Volcano, the larger of two historic eruptive centers on Pagan Island, Mariana Islands. The eruption was preceded by increased numbers of locally felt earthquakes beginning in late March or early April and by new ground cracks, new sublimates, and increased gas emissions. A swarm of felt earthquakes began at 0745h (local time = UCT+10 hours) 15 May, and at 0915 h, closely following a loud sonic boom, a strong plinian column issued from the volcano. The high-altitude ash cloud (at least 13.5 km) travelled south-southeast, but ash and scoria deposits were thickest (> 2 m) in the NW sector of the island because of the prevailing low-altitude southeasterly winds. The early activity of 15 May probably involved magmatic eruption along a fissure system oriented about N10??E. However, the eruption became hydromagmatic, possibly within minutes, and was largely restricted to three long-lived vents. The northernmost of these built a substantial new scoria-ash cinder cone. Flows and air-fall deposits, consisting almost entirely of juvenile material, exceeded 105 ?? 106 m3 in volume (75 ?? 106 m3 of magma) on land and at least 70-100 ?? 606 m3 at sea. An unknown volume was carried away by stratospheric winds. Lithic blocks and juvenile bombs as large as 1 m in diameter were thrown more than 2 km from the summit, and evidence for base-surge was observed in restricted corridors as low as 200 m elevation on the north and south slopes of the volcano. Neither of these events resulted in serious injuries to the 54 residents of the island, nor did the eruption produce serious chemical hazards in their water supply. Weak eruptions occurred during the ensuing month, and some of these were monitored by ground observations, seismic monitoring, and deformation studies. Precursory seismicity and possibly deformation occurred with some of the observed eruptions. More vigorous eruptions were reported by visiting residents in late

  15. ASTER-SRTM Perspective of Mount Oyama Volcano, Miyake-Jima Island, Japan

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Mount Oyama is a 820-meter-high (2,700 feet) volcano on the island of Miyake-Jima, Japan. In late June 2000, a series of earthquakes alerted scientists to possible volcanic activity. On June 27, authorities evacuated 2,600 people, and on July 8 the volcano began erupting and erupted five times over that week. The dark gray blanket covering green vegetation in the image is the ash deposited by prevailing northeasterly winds between July 8 and 17. This island is about 180 kilometers (110 miles) south of Tokyo and is part of the Izu chain of volcanic islands that runs south from the main Japanese island of Honshu. Miyake-Jima is home to 3,800 people. The previous major eruptions of Mount Oyama occurred in 1983 and 1962, when lava flows destroyed hundreds of houses. An earlier eruption in 1940 killed 11 people.

    This image is a perspective view created by combining image data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) aboard NASA's Terra satellite with an elevation model from the Shuttle Radar Topography Mission (SRTM). Vertical relief is exaggerated, and the image includes cosmetic adjustments to clouds and image color to enhance clarity of terrain features.

    The ASTER instrument is a cooperative project between NASA, JPL, and the Japanese Ministry of International Trade and Industry.

    Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11,2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the

  16. Experimental constraints on steam-driven eruptions at White Island volcano (New Zealand)

    NASA Astrophysics Data System (ADS)

    Scheu, Bettina; Mayer, Klaus; Gilg, H. Albert; Heap, Michael J.; Kennedy, Ben M.; Lavallée, Yan; Letham-Brake, Mark; Jolly, Arthur; Dingwell, Donald B.

    2015-04-01

    The recent activity at White Island volcano is primarily characterized by strong hydrothermal activity interspersed by sequences of phreatic and phreatomagmatic eruptions, down to micro-eruptions through a mud-rich crater lake. We analyzed the response of various sample types to rapid decompression caused by steam-flashing and/or gas expansion, mimicking steam-driven (phreatic) eruptions. The samples investigated comprise unconsolidated ash/lapilli as well as consolidated ash tuffs with different degree of alteration. All sample sets underwent, where possible, microstructural, geochemical and petrophysical characterization (as porosity, permeability and uniaxial compressive strength (UCS)). This allowed us to assess the role of following factors for phreatic eruptions: (1) PT-conditions leading to either steam-flashing or steam expansion (2) the behavior of loose versus consolidated material, as the influence of fragmentation, ejection velocity, grain size reduction (3) the porosity and its changes, (4) the alteration of the samples, leading to changes in UCS, porosity, and permeability. Besides their role during the short moment of a phreatic eruption itself, the strength and the permeability of rocks of the entire White Island volcanic complex and in detail above the hydrothermal system in the crater area are key factors for the recent activity at White Island. They crucially influence the distribution of fluids and gases; strong and low-permeable layers can act as pressure seals, defining the area and overpressure of a steam-driven eruption.

  17. Impact of permethrin-impregnated mosquito nets compared with DDT house-spraying against malaria transmission by Anopheles farauti and An.punctulatus in the Solomon Islands.

    PubMed

    Hii, J L; Kanai, L; Foligela, A; Kan, S K; Burkot, T R; Wirtz, R A

    1993-10-01

    In villages of northern Guadalcanal in the Solomon Islands, where the predominant malaria vector is An.farauti No. 1 and An.puctulatus is also involved, malaria transmission rates were compared for three zones: (1) non-intervention: 438 people in seventeen villages; (2) residual DDT house-spraying two cycles per year: 644 people in thirty villages; (3) bednets impregnated with permethrin 0.5 g/m2 twice per year, used by 580 people in sixteen villages. Regular DDT spraying in zones 1 and 3 had been withdrawn 18 months previously. Malariological blood smear surveys of children aged 1-9 years in August 1986 to January 1987 showed a mean baseline malaria parasite rate of 38% (32/84). By February 1988, 18 months after introduction of impregnated bednets, the Plasmodium falciparum infection rate in children was lowest in the zone using impregnated bednets (21% of 29), intermediate in the untreated zone (29% of 34) and highest in the DDT zone (46% of 53), but these differences were not statistically significant. P. vivax infection rates were 9-14%. Using ELISA tests for malaria circumsporozoite antigen in the vectors, overall positivity rates were 0.7% of 49,902 An.farauti and 2.54% of 118 An.punctulatus, comprising 228 P.falciparum and 124 P.vivax infections. In the study zones, vector positivity rates were 0.93% of 31,615 An.farauti in the untreated zone; 0.32% of 16,883 An.farauti in the DDT zone; 0.07% of 1404 An.farauti and 2.54% of 118 An.puctulatus in the impregnated bednet zone. here was no significant correlation between malaria parasite rates in the vectors and the children.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8268487

  18. Ten years of satellite observations reveal highly variable sulphur dioxide emissions at Anatahan Volcano, Mariana Islands

    NASA Astrophysics Data System (ADS)

    McCormick, Brendan; Popp, Christoph; Andrews, Benjamin; Cottrell, Elizabeth

    2015-07-01

    Satellite remote sensing enables continuous multiyear observations of volcanic activity in remote settings. Anatahan (Mariana Islands) is a remote volcano in the western North Pacific. Available ground-based measurements of sulphur dioxide (SO2) gas emissions at Anatahan place it among thelargest volcanic SO2 sources worldwide. These ground-based measurements, however, are restricted to eruptive intervals. Anatahan's activity since 2003 has been dominated temporally by prolonged periods of quiescence. Using 10 years of satellite observations from OMI, AIRS, SCIAMACHY, and GOME-2, we report highly variable SO2 emissions within and between eruptive and quiescent intervals at Anatahan. We find close correspondence between levels of activity reported at the volcano and levels of SO2 emissions detected from space. Eruptive SO2 emission rates have a mean value of ˜6400 t d-1, but frequently are in excess of 20,000 t d-1. Conversely, SO2 emissions during quiescent intervals are below the detection limit of space-based sensors and therefore are not likely to exceed ˜300 t d-1. We show that while Anatahan occupies a quiescent state for 85% of the past 10 years, only ˜15% of total SO2 emissions over this interval occur during quiescence, with the remaining ˜85% released in short duration but intense syn-eruptive degassing. We propose that the integration of multiyear satellite data sets and activity histories are a powerful complement to targeted ground-based campaign measurements in better describing the long-term degassing behavior of remote volcanoes.

  19. Mechanical behaviour and failure modes in the Whakaari (White Island volcano) hydrothermal system, New Zealand

    NASA Astrophysics Data System (ADS)

    Heap, Michael J.; Kennedy, Ben M.; Pernin, Noémie; Jacquemard, Laura; Baud, Patrick; Farquharson, Jamie I.; Scheu, Bettina; Lavallée, Yan; Gilg, H. Albert; Letham-Brake, Mark; Mayer, Klaus; Jolly, Arthur D.; Reuschlé, Thierry; Dingwell, Donald B.

    2015-03-01

    Volcanic hydrothermal systems host a prodigious variety of physico-chemical conditions. The physico-chemical state and mechanical behaviour of rocks within is correspondingly complex and often characterised by vast heterogeneity. Here, we present uniaxial and triaxial compression experiments designed to investigate the breadth of mechanical behaviour and failure modes (dilatant or compactant) for hydrothermally-altered lava and ash tuff deposits from Whakaari (White Island volcano) in New Zealand, a volcano with a well-documented and very active hydrothermal system. Our deformation experiments show that the failure mode of low porosity lava remains dilatant over a range of depths (up to pressures corresponding to depths of about 2 km). Upon failure, shear fractures, the result of the coalescence of dilatational microcracks, are universally present. The high porosity ash tuffs switch however from a dilatant to a compactant failure mode (driven by progressive distributed pore collapse) at relatively low pressure (corresponding to a depth of about 250 m). We capture the salient features of the dynamic conditions (e.g., differential stress, effective pressure) in a schematic cross section for the Whakaari hydrothermal system and map, for the different lithologies, areas susceptible to either dilatant vs. compactive modes of failure. The failure mode will impact, for example, the evolution of rock physical properties (e.g., porosity, permeability, and elastic wave velocity) and the nature of the seismicity accompanying periods of unrest. We outline accordingly the potential implications for the interpretation of seismic signals, outgassing, ground deformation, and the volcanic structural stability for Whakaari and similar hydrothermally-active volcanoes worldwide.

  20. Volcanic emissions from soils at the base of La Fossa volcano, Vulcano island, Italy

    NASA Astrophysics Data System (ADS)

    Obenholzner, J. H.; Parks, J. L.

    2006-12-01

    A top-sealed plastic tube with a diameter of ca. 15 cm had been buried vertically at the base of La Fossa volcano, Volcano island, Italy, next to the front of the obsidian flow. The tube had been filled with quartz wool to condense vapors emanating from the soil. At ca. 75 cm below the surface the sample had been exposed to vapors from Sept. 2005 to April 2006. The leached sample had not been in touch with the ground. Another glass wool cushion (ca. 3 cm thick) had been underneath to minimize capillary effects. Leaching of the quartz wool and ICP-MS analysis documented positive values for: Mg, Al, Si, P, K, Ca, Cr, Mn, Ni, Cu, Zn, Cd, Sn, Pb. Leaching with nitric acid documented also V and Fe. Acid leaching produced higher values for all elements, except K and Sn, than leaching with deionized water. Negative values had been obtained for As, Se, Mo. Influence from soil breathing can be excluded as the active fumaroles contain As and Se. This experiment documents for the first time an unknown element transport by vapors/gases through a volcanic edifice interacting with hydrothermal and magmatic gases. It remains unknown if elements detected are entering the atmosphere or are getting adsorbed onto the volcanic ash soil particles derived from reworked surge beds. This question is very important as soils might be an unknown filter medium to filter volcanically polluted air in case of major volcanic crises. Data can be obtained from the authors.

  1. Tetrodotoxin and Its Analogues in the Pufferfish Arothron hispidus and A. nigropunctatus from the Solomon Islands: A Comparison of Their Toxin Profiles with the Same Species from Okinawa, Japan.

    PubMed

    Puilingi, Clyde Gorapava; Kudo, Yuta; Cho, Yuko; Konoki, Keiichi; Yotsu-Yamashita, Mari

    2015-08-26

    Pufferfish poisoning has not been well documented in the South Pacific, although fish and other seafood are sources of protein in these island nations. In this study, tetrodotoxin (TTX) and its analogues in each organ of the pufferfish Arothron hispidus and A. nigropunctatus collected in the Solomon Islands were investigated using high resolution LC-MS. The toxin profiles of the same two species of pufferfish from Okinawa, Japan were also examined for comparison. TTXs concentrations were higher in the skin of both species from both regions, and relatively lower in the liver, ovary, testis, stomach, intestine, and flesh. Due to higher TTX concentrations (51.0 and 28.7 µg/g at highest) detected in the skin of the two species from the Solomon Islands (saxitoxin was <0.02 µg/g), these species should be banned from consumption. Similar results were obtained from fish collected in Okinawa, Japan: TTX in the skin of A. hispidus and A. nigropunctatus were 12.7 and 255 µg/g, respectively, at highest, and saxitoxin was also detected in the skin (2.80 µg/g at highest) and ovary of A. hispidus. TTX, 5,6,11-trideoxyTTX (with its 4-epi form), and its anhydro forms were the most abundant, and 11-oxoTTX was commonly detected in the skin.

  2. Tetrodotoxin and Its Analogues in the Pufferfish Arothron hispidus and A. nigropunctatus from the Solomon Islands: A Comparison of Their Toxin Profiles with the Same Species from Okinawa, Japan.

    PubMed

    Puilingi, Clyde Gorapava; Kudo, Yuta; Cho, Yuko; Konoki, Keiichi; Yotsu-Yamashita, Mari

    2015-09-01

    Pufferfish poisoning has not been well documented in the South Pacific, although fish and other seafood are sources of protein in these island nations. In this study, tetrodotoxin (TTX) and its analogues in each organ of the pufferfish Arothron hispidus and A. nigropunctatus collected in the Solomon Islands were investigated using high resolution LC-MS. The toxin profiles of the same two species of pufferfish from Okinawa, Japan were also examined for comparison. TTXs concentrations were higher in the skin of both species from both regions, and relatively lower in the liver, ovary, testis, stomach, intestine, and flesh. Due to higher TTX concentrations (51.0 and 28.7 µg/g at highest) detected in the skin of the two species from the Solomon Islands (saxitoxin was <0.02 µg/g), these species should be banned from consumption. Similar results were obtained from fish collected in Okinawa, Japan: TTX in the skin of A. hispidus and A. nigropunctatus were 12.7 and 255 µg/g, respectively, at highest, and saxitoxin was also detected in the skin (2.80 µg/g at highest) and ovary of A. hispidus. TTX, 5,6,11-trideoxyTTX (with its 4-epi form), and its anhydro forms were the most abundant, and 11-oxoTTX was commonly detected in the skin. PMID:26343722

  3. Tetrodotoxin and Its Analogues in the Pufferfish Arothron hispidus and A. nigropunctatus from the Solomon Islands: A Comparison of Their Toxin Profiles with the Same Species from Okinawa, Japan

    PubMed Central

    Gorapava Puilingi, Clyde; Kudo, Yuta; Cho, Yuko; Konoki, Keiichi; Yotsu-Yamashita, Mari

    2015-01-01

    Pufferfish poisoning has not been well documented in the South Pacific, although fish and other seafood are sources of protein in these island nations. In this study, tetrodotoxin (TTX) and its analogues in each organ of the pufferfish Arothron hispidus and A. nigropunctatus collected in the Solomon Islands were investigated using high resolution LC-MS. The toxin profiles of the same two species of pufferfish from Okinawa, Japan were also examined for comparison. TTXs concentrations were higher in the skin of both species from both regions, and relatively lower in the liver, ovary, testis, stomach, intestine, and flesh. Due to higher TTX concentrations (51.0 and 28.7 µg/g at highest) detected in the skin of the two species from the Solomon Islands (saxitoxin was <0.02 µg/g), these species should be banned from consumption. Similar results were obtained from fish collected in Okinawa, Japan: TTX in the skin of A. hispidus and A. nigropunctatus were 12.7 and 255 µg/g, respectively, at highest, and saxitoxin was also detected in the skin (2.80 µg/g at highest) and ovary of A. hispidus. TTX, 5,6,11-trideoxyTTX (with its 4-epi form), and its anhydro forms were the most abundant, and 11-oxoTTX was commonly detected in the skin. PMID:26343722

  4. Distributed Coseismic and Early Postseismic Dip-Slip from the 1 April 2007 Solomon Islands Earthquake: A Unique Image of Near-Trench Rupture

    NASA Astrophysics Data System (ADS)

    Chen, T.; Newman, A. V.; Fritz, H.

    2008-12-01

    We estimate the spatial distribution of dip-slip in the 1 April 2007 magnitude MW=8.1 Solomon earthquake, which created a locally large tsunami with runup heights up to 12 m. The event is unique in that involved the rupture of at least two subducting plates, and that land occurs very close to the trench on the hanging wall side. The occurrence of islands extremely proximal to the trench allowed for the collection of near-shore uplift and subsidence information from costal areas (including the exposure and subsidence of corals), hence giving a unique well-resolved image of the near-trench geodetically derived slip. Two surveys, taken between 1 week and 1 month after the event primarily across the southern portion of the slip zone, comprise a dataset of approximately 100 measurements of between +3.6 and -1.5 m of vertical displacements [Fritz and Kalligeris, 2008; Taylor et al., 2008]. We use the Okada [1992] elastic dislocation model, to explore the distribution of dip-slip on discrete patches. To maintain a realistic distribution of slip we smooth the solution by attempting to minimize the second-order spatial derivative of slip, hence minimizing the stress change across the system. Because data are only vertical in nature and the expected strike-slip component of the thrust is small, only the dip-slip component of rupture was considered. Early results show highly variable dip-slip both along-strike and down- dip, with a significant focus of slip in the shallow near trench area. If real, this near-trench focusing may explain the locally high runup on portions of Simbo Island. Because it is not certain how much of the modeled slip occurred due to coseismic versus post-seismic recovery and afterslip, we explore the variability of solutions between the two surveys and compare results with the available spatial distribution of co-seismic finite-slip model of C. Ji [unpublished, 2007].

  5. Changes in vector species composition and current vector biology and behaviour will favour malaria elimination in Santa Isabel Province, Solomon Islands

    PubMed Central

    2011-01-01

    Background In 2009, Santa Isabel Province in the Solomon Islands embarked on a malaria elimination programme. However, very little is known in the Province about the anopheline fauna, which species are vectors, their bionomics and how they may respond to intensified intervention measures. The purpose of this study was to provide baseline data on the malaria vectors and to ascertain the possibility of successfully eliminating malaria using the existing conventional vector control measures, such as indoor residual spraying (IRS) and long-lasting insecticidal nets (LLIN). Methods Entomological surveys were undertaken during October 2009. To determine species composition and distribution larval surveys were conducted across on the whole island. For malaria transmission studies, adult anophelines were sampled using human landing catches from two villages - one coastal and one inland. Results Five Anopheles species were found on Santa Isabel: Anopheles farauti, Anopheles hinesorum, Anopheles lungae, Anopheles solomonis, and Anopheles nataliae. Anopheles hinesorum was the most widespread species. Anopheles farauti was abundant, but found only on the coast. Anopheles punctulatus and Anopheles koliensis were not found. Anopheles farauti was the only species found biting in the coastal village, it was incriminated as a vector in this study; it fed early in the night but equally so indoors and outdoors, and had a low survival rate. Anopheles solomonis was the main species biting humans in the inland village, it was extremely exophagic, with low survival rates, and readily fed on pigs. Conclusion The disappearance of the two major vectors, An. punctulatus and An. koliensis, from Santa Isabel and the predominance of An. hinesorum, a non-vector species may facilitate malaria elimination measures. Anopheles farauti was identified as the main coastal vector with An. solomonis as a possible inland vector. The behaviour of An. solomonis is novel as it has not been previously found

  6. Oligocene to Recent tectonic history of the Central Solomon intra-arc basin as determined from marine seismic reflection data and compilation of onland geology

    NASA Astrophysics Data System (ADS)

    Cowley, Shane; Mann, Paul; Coffin, M. F.; Shipley, Thomas H.

    2004-10-01

    later during the Pliocene in the northwest (Shortland subbasin of the CSB); folds in the CSB form by inversion of normal faults formed during Phase 1; Phinney et al. [Sequence stratigraphy, structural style, and age of deformation of the Malaita accretionary prism (Solomon arc-Ontong Java Plateau convergent zone)] show a coeval pattern of southeast to northwest younging in folding and faulting of the MAP. Phase 3: Late Pliocene-early Pleistocene arc polarity reversal and subduction initiation at the San Cristobal trench. Effects of this event in the CSB include the formation of a chain of volcanoes above the subducting Australia plate at the San Cristobal trench, the formation of the broad synclinal structure of the CSB with evidence for truncation at the uplifted flanks, and widespread occurrence of slides and "seismites" (deposits formed by seismic shaking). Phase 4: Pleistocene to Recent continued shortening and synclinal subsidence of the CSB. Continued Australia-Pacific oblique plate convergence has led to deepening of the submarine, elongate basin axis of the synclinal CSB and uplift of the dual chain of the islands on its flanks.

  7. Satellite and ground observations of the June 2009 eruption of Sarychev Peak volcano, Matua Island, Central Kuriles

    NASA Astrophysics Data System (ADS)

    Rybin, Alexander; Chibisova, Marina; Webley, Peter; Steensen, Torge; Izbekov, Pavel; Neal, Christina; Realmuto, Vince

    2011-11-01

    After 33 years of repose, one of the most active volcanoes of the Kurile island arc—Sarychev Peak on Matua Island in the Central Kuriles—erupted violently on June 11, 2009. The eruption lasted 9 days and stands among the largest of recent historical eruptions in the Kurile Island chain. Satellite monitoring of the eruption, using Moderate Resolution Imaging Spectroradiometer, Meteorological Agency Multifunctional Transport Satellite, and Advanced Very High Resolution Radiometer data, indicated at least 23 separate explosions between 11 and 16 June 2009. Eruptive clouds reached altitudes of generally 8-16 km above sea level (ASL) and in some cases up to 21 km asl. Clouds of volcanic ash and gas stretched to the north and northwest up to 1,500 km and to the southeast for more than 3,000 km. For the first time in recorded history, ash fall occurred on Sakhalin Island and in the northeast sector of the Khabarovsky Region, Russia. Based on satellite image analysis and reconnaissance field studies in the summer of 2009, the eruption produced explosive tephra deposits with an estimated bulk volume of 0.4 km3. The eruption is considered to have a Volcanic Explosivity Index of 4. Because the volcano is remote, there was minimal risk to people or infrastructure on the ground. Aviation transport, however, was significantly disrupted because of the proximity of air routes to the volcano.

  8. Satellite and ground observations of the June 2009 eruption of Sarychev Peak volcano, Matua Island, Central Kuriles

    USGS Publications Warehouse

    Rybin, A.; Chibisova, M.; Webley, P.; Steensen, T.; Izbekov, P.; Neal, C.; Realmuto, V.

    2011-01-01

    After 33 years of repose, one of the most active volcanoes of the Kurile island arc-Sarychev Peak on Matua Island in the Central Kuriles-erupted violently on June 11, 2009. The eruption lasted 9 days and stands among the largest of recent historical eruptions in the Kurile Island chain. Satellite monitoring of the eruption, using Moderate Resolution Imaging Spectroradiometer, Meteorological Agency Multifunctional Transport Satellite, and Advanced Very High Resolution Radiometer data, indicated at least 23 separate explosions between 11 and 16 June 2009. Eruptive clouds reached altitudes of generally 8-16 km above sea level (ASL) and in some cases up to 21 km asl. Clouds of volcanic ash and gas stretched to the north and northwest up to 1,500 km and to the southeast for more than 3,000 km. For the first time in recorded history, ash fall occurred on Sakhalin Island and in the northeast sector of the Khabarovsky Region, Russia. Based on satellite image analysis and reconnaissance field studies in the summer of 2009, the eruption produced explosive tephra deposits with an estimated bulk volume of 0. 4 km3. The eruption is considered to have a Volcanic Explosivity Index of 4. Because the volcano is remote, there was minimal risk to people or infrastructure on the ground. Aviation transport, however, was significantly disrupted because of the proximity of air routes to the volcano. ?? 2011 Springer-Verlag.

  9. Geological aspects of the 2003 2004 eruption of Anatahan Volcano, Northern Mariana Islands

    NASA Astrophysics Data System (ADS)

    Nakada, Setsuya; Matsushima, Takeshi; Yoshimoto, Mitsuhiro; Sugimoto, Takeshi; Kato, Teruyuki; Watanabe, Tsuyoshi; Chong, Ramon; Camacho, Juan T.

    2005-08-01

    Anatahan Volcano, Northern Mariana Islands, began erupting in May-June 2003. A series of subplinian explosive eruptions of andesite magma began at the Eastern Crater in the eastern part of the summit caldera on the evening of 10 May. Brown tephra was sent mainly westward by strong winds. Small-scale pyroclastic surges were discharged eastward outside the caldera in late May. An andesite lava dome that had once filled the inner crater was fragmented by phreatomagmatic explosions in the middle of June. The phreatomagmatic explosions probably occurred due to interaction of the magma head with groundwater around the crater, and abundant very fine ash ("gray tephra") was discharged within the caldera and over most of the island. The volume of eruption products of the May-June eruption was estimated to be 1.4 × 10 7 m 3 dense-rock-equivalent. Erupted pumices and lava are aphyric andesite and are variously colored depending on their vesicularity. The SiO 2 contents of erupted materials decreased slightly with time. The fine gray ash is depleted in alkalies, probably due to leaching by acid hydrothermal fluids during explosions. Seismic activity resumed in late March 2004, and small strombolian-like explosions were repeated in May and June 2004. About half of the inner crater was filled with new scoria and lava.

  10. Relationship between two Solomon Islands Earthquakes in 2007 (M8.1), 2010 (M7.1), and Seismic Gap along the Subduction Zone, Revealed by ALOS/PALSAR

    NASA Astrophysics Data System (ADS)

    Miyagi, Y.; Ozawa, T.

    2010-12-01

    The Solomon Islands are located in the southwest of the Pacific Ocean. The Australian, Woodlark, and Solomon Sea plates subduct toward the northeast beneath the Pacific plate. Interaction among these four plates cause complicated tectonics around the Solomon Islands, and have caused interplate earthquakes in the subduction zone (e.g. Lay and Kanamori, 1980; Xu and Schwarts, 1993). On April 1, 2007 (UTC), an M8.1 interplate earthquake occurred in the subduction zone between the Pacific Plate and the Australian Plate. This earthquake was accompanied by a large tsunami and caused considerable damage in the area. The Japan Aerospace Exploration Agency (JAXA) carried out emergency observations using the Phased Array type L-band Synthetic Aperture Rader (PALSAR) installed on Advanced Land Observing Satellite (ALOS), and detected more than 2m of maximum displacement using differential interferometric SAR (DInSAR) technique. Miyagi et al. (2009) estimated a slip distribution of the seismic fault mainly from the PALSAR/DInSAR data and suggested that most of a seismic gap was filled by the 2007 events, but a small seismic gap connecting to an Mw7.0-sized earthquake still remained. On January 3, 2010, an M7.1 earthquake occurred in the vicinity of the remnant seismic gap. ALOS/PALSAR observed epicentral area both before and after the event, and detected crustal deformation associated with the earthquake. We inferred fault model using the PALSAR/DInSAR data and concluded that the 2010 event was the supposed thrust earthquake filling the remnant seismic gap. A distribution of coulomb failure stress change in the epicentral area after the 2007 event suggested the possibility that the 2010 event was triggered by the 2007 earthquake.

  11. Two Decades of Degassing at Kilauea Volcano, Hawai`i: Perspectives on Island Impacts

    NASA Astrophysics Data System (ADS)

    Elias, T.; Sutton, A. J.

    2003-12-01

    The ongoing eruption of Kilauea provides an opportunity to examine how volcanic emissions impact the natural and human environment of the island of Hawai`i. Kilauea has released ˜ 13 megatons of SO2 gas into the troposphere since the current eruption began in 1983, more than any single anthropogenic source in the U.S. During prevailing trade wind conditions, measurements of SO2 gas, aerosol mass, and aerosol acidity downwind of Kilauea document the conversion of SO2 to acid aerosol as the plume propagates to the leeward side of the island. Lidar measurements suggest a gas-to-particle conversion rate (t1/2) of 6 hours. When trade winds are disrupted, ambient SO2 and particle measurements in Hawai`i Volcanoes National Park have shown episodes of particle concentrations of ˜ 100 μ g/m3 and SO2 concentrations in excess of 4000 ppb. Federal health standards and WHO guidelines for SO2 have been exceeded repeatedly at this near-source location. Documented effects from volcanic emissions on the island of Hawai`i include the rapid corrosion of metal objects, degradation of domestic water quality, agricultural crop damage, and adverse impacts on human respiratory and pulmonary function. Other impacts may include decreases in local rainfall and increased mortality of asthmatics. For the period 1986 to 1993, after the eruption became continuous, deaths from asthma on the island of Hawai`i increased by a factor of ten. Three current health studies seek to investigate the relationship between exposure to volcanic pollution and health effects. In addition to measuring gas and particle exposures, these studies examine lung development in children around the island, disease prevalence in adults residing in communities downwind of volcanic degassing sources, and acute effects in asthmatic children and healthy children and adults. In the absence of conclusive evidence linking exposure and health effects, the USGS, in collaboration with the National Park Service, has developed a

  12. 2005 Volcanic Activity in Alaska, Kamchatka, and the Kurile Islands: Summary of Events and Response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, R.G.; Neal, C.A.; Dixon, J.P.; Ushakov, Sergey

    2008-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptive activity or suspected volcanic activity at or near 16 volcanoes in Alaska during 2005, including the high profile precursory activity associated with the 2005?06 eruption of Augustine Volcano. AVO continues to participate in distributing information about eruptive activity on the Kamchatka Peninsula, Russia, and in the Kurile Islands of the Russian Far East, in conjunction with the Kamchatkan Volcanic Eruption Response Team (KVERT) and the Sakhalin Volcanic Eruption Response Team (SVERT), respectively. In 2005, AVO helped broadcast alerts about activity at 8 Russian volcanoes. The most serious hazard posed from volcanic eruptions in Alaska, Kamchatka, or the Kurile Islands is the placement of ash into the atmosphere at altitudes traversed by jet aircraft along the North Pacific and Russian Trans East air routes. AVO, KVERT, and SVERT work collaboratively with the National Weather Service, Federal Aviation Administration, and the Volcanic Ash Advisory Centers to provide timely warnings of volcanic eruptions and the production and movement of ash clouds.

  13. Chemical and U-Pb dating investigation of zircons from alnöites on Malaita, Solomon Islands: evidence for prolonged kimberlite-type magmatic activity

    NASA Astrophysics Data System (ADS)

    Simonetti, A.; Neal, C. R.

    2009-12-01

    The Solomon Islands chain is located in an area dominated by the Ontong Java Plateau (OJP). The island of Malaita formed at the obducted leading edge of the OJP and is geologically distinct from the islands to the west. Occurrences of pipe-like bodies of alnöite outcrop within limestones and mudstones in northern Malaita and have been seismically imaged offshore within the OJP. The Malaita alnöite is silica-undersaturated and contains a rich and varied suite of peridotite xenoliths and megacrysts (clinopyroxene, garnet, ilmenite, phlogopite, and minor zircon). The alnöite and associated megacrysts have been the focus of detailed chemical and radiogenic isotope investigations but the exact age of alnöite emplacement remains debatable. Previously reported ages for minerals associated with the Malaita alnöites include an Ar-Ar date of 34 Ma for phlogopite from a mantle xenolith, and a single 206Pb/238U date of 33.9 Ma obtained from a single zircon megacryst. Here we report on a detailed chemical (major and trace element) and U-Pb age investigation of zircon crystals recovered from rivers in the Aluta, Kwainale, and Faufaumela regions of central Malaita. The major element (SiO2, ZrO2, and HfO2) composition and back scattered electron (BSE) imaging of mm- to cm-sized zircons from the three locations were conducted by electron microprobe analysis. The data reveal a variation in the Zr/Hf ratio (45 to 57) for zircons from the Aluta area, whereas this ratio is relatively uniform in most zircons from Kwainale (Zr/Hf 45 to 48). Of importance, the BSE imaging reveals the homogeneous nature of the grains and the lack of inherited components. Trace element compositions of the zircon crystals were obtained by laser ablation (LA)-ICP-MS and these reveal similar chondrite-normalized REE patterns at variable enrichment levels for all grains analyzed; these patterns along with the U, Th, and Pb contents are similar to those documented for mantle-derived zircons formed within

  14. A cluster randomized controlled cross-over bed net acceptability and preference trial in Solomon Islands: community participation in shaping policy for malaria elimination

    PubMed Central

    2009-01-01

    Background A key component of the malaria elimination strategy in Solomon Islands (SI) is widespread coverage of long-lasting insecticidal nets (LLINs). The success of this strategy is dependent on LLIN acceptability and compliance. There has been unresolved debate among policy makers and donors as to which type of LLIN would be most appropriate for large-scale distribution in SI, and anecdotal reports of a lack of acceptability of certain brands of LLINs. A cluster randomized controlled crossover bed net acceptability and preference trial was therefore carried out from July to September, 2008 to inform policy and to facilitate community engagement and participation in the selection of the most appropriate LLIN for use in SI. Method A three-stage sampling method was used to randomly select the study population from Malaita Province, SI. Three brands of LLINs were assessed in this study: Olyset®, PermaNet® and DuraNet®. Bed net acceptability and preference were evaluated through surveys at three defined time points after short and longer-term trial of each LLIN. Results The acceptability of PermaNet® after short-term use (96.5%) was significantly greater than Olyset® (67.3%, p < 0.001) and DuraNet® (69.8%, p < 0.001). The acceptability of DuraNet® and Olyset® after short-term use was not significantly different at the 5% level. LLINs that were perceived not to prevent mosquito bites were significantly less acceptable than LLINs that were perceived to prevent mosquito bites (OR 0.15; 95%CI 0.03 to 0.6). LLINs that allow a pleasant night's sleep (OR 6.3; 95%CI:3.3-12.3) and have a soft texture (OR 5.7; 95%CI:1.9-20.5) were considered more acceptable than those that did not. Olyset®'s acceptability decreased over time and this was due to net wrinkling/shrinkage after washing resulting in reduced efficiency in preventing mosquito bites. The increase in DuraNet® acceptability was a result of a reduction in minor adverse events following longer-term use

  15. Electric and magnetic phenomena observed before the volcano-seismic activity in 2000 in the Izu Island Region, Japan

    PubMed Central

    Uyeda, S.; Hayakawa, M.; Nagao, T.; Molchanov, O.; Hattori, K.; Orihara, Y.; Gotoh, K.; Akinaga, Y.; Tanaka, H.

    2002-01-01

    Significant anomalous changes in the ultra low frequency range (≈0.01 Hz) were observed in both geoelectric and geomagnetic fields before the major volcano-seismic activity in the Izu Island region, Japan. The spectral intensity of the geoelectric potential difference between some electrodes on Niijima Island and the third principal component of geomagnetic field variations at an array network in Izu Peninsula started to increase from a few months before the onset of the volcano-seismic activity, culminating immediately before nearby magnitude 6 class earthquakes. Appearance of similar changes in two different measurements conducted at two far apart sites seems to provide information supporting the reality of preseismic electromagnetic signals. PMID:12032286

  16. Petroleum potential of volcanogenic and volcano-sedimentary rocks in ancient and recent island arcs: Caucasus, Komandorskie, and Kuril islands, eastern Kamchatka

    SciTech Connect

    Levin, L.E. )

    1993-09-01

    In the Late Cretaceous-Eocene, subduction of the Tethys oceanic plate under the island arc of the lesser Caucasus contributed to the appearance of the special conditions favorable for petroleum occurrence: (1) tectono-magmatic destruction of the crust of the Transcaucasus median massif and formation of hydrocarbon traps of different types and origins, and (2) high heat flow lasting until the recent epoch. These led flow-intensive generation of hydrocarbons in the shallow-water sediments of the paleoshelf of the Transcaucasus massif and accumulation of hydrocarbons not only in the sedimentary but also in the volcanogenic and volcano-sedimentary reservoirs (Samgori-Patardzeuli, Muradhanly fields, etc.). At the end of the Oligocene, the geodynamic setting in the northwestern margins of the Pacific Ocean was mainly similar to that within the Transcaucasus median massif. At the end of Oligocene-Miocene, such conditions determined the tectono-magmatic destruction of the continental crust and formation of the series of interarc rifts. The main fields of Japan, with accumulations in the volcanogenic and volcano-sedimentary rocks, are concentrated here. Its analog is the rift located in the southern part of a single east Kuril basin, where petroleum occurrence is only inferred. In the separate troughs, the thickness of the volcano-sedimentary cover is 4-6 km. The stratigraphic section of the cover contains the volcanic and volcano-sedimentary sediments of the Neogene-Pleistocene. The studies of the sections of the Komandorskie islands, eastern Kamchatka, Kuril Islands, and western Sakhalin indicate that distribution of reservoirs depends on the stage of evolution of the rifts and adjacent island arcs.

  17. Monitoring Cumbre Vieja volcano (La Palma, Canary Islands) from 2001 to 2015 by means of diffuse CO2 degassing

    NASA Astrophysics Data System (ADS)

    Padrón, Eleazar; Berry, Hannah; Robinson, Helen; Rodríguez, Fátima; Dionis, Samara; Pérez, Nemesio M.

    2016-04-01

    La Palma Island, the fifth longest (706 km2) and second highest (2,423 m asl) of the Canary Islands, is located at the northwestern end of the archipelago. Subaerial volcanic activity on La Palma started ˜2.0 My ago and has taken place exclusively at the southern part of the island in the last 123 ka, where Cumbre Vieja volcano, the most active basaltic volcano in the Canaries, has been constructed. Cumbre Vieja volcano, which has been likened to a Hawaiian-style rift zone, includes a main north-south rift zone 20 km long and up to 1,950 m in elevation, and covers 220 km2 with vents located also at the northwest and northeast. Nowadays, there are no visible gas emissions from fumaroles or hot springs at Cumbre Vieja, but large amounts of CO2 are released as diffuse soil emanations from the flanks of the volcano. Recent studies have shown that enhanced endogenous contributions of deep-seated CO2 might have been responsible for higher diffuse CO2 emission values (Padrón et al., 2015). We report here the latest results of the diffuse CO2 efflux survey at Cumbre Vieja volcano. The CO2 efflux measurements were taken using the accumulation chamber method in the summer period of 2015 to constrain the total CO2 output from the studied area and to evaluate occasional CO2 efflux surveys as a volcanic surveillance tool for Cumbre Vieja. Soil CO2 efflux values ranged from non-detectable up to 360 g m-2 d-1. Spatial distribution maps were constructed following the sequential Gaussian simulation (sGs) procedure. The spatial distribution of diffuse CO2 emission values did not seem to be controlled by the main structural features of the volcano since the highest values were measured in the southern part. The total CO2 output released to the atmosphere in a diffuse way has been estimated at 359 t d-1, which represents one of the lowest emission rates reported since 1997 (Padrón et al., 2015). Our results confirm the volcanic quiescence state of Cumbre Vieja, but reassert the

  18. Application of emulsion imaging system for cosmic-ray muon radiography to explore the internal structure of Teide and Cumbre Vieja volcanoes in the Canary Islands, Spain

    NASA Astrophysics Data System (ADS)

    Hernandez Perez, P. A.; Tanaka, H.; Miyamoto, S.; Perez, N.; Barrancos, J.; Padron, E.; Hernandez, I.

    2012-12-01

    The internal structure of volcanoes, especially in their up per part, is product of past eruptions. Therefore, the knowledge of the internal structure of a volcano is of great importance for understanding its behaviour and to forecast the nature and style of the next eruptions. For these reasons, during past years scientists have made a big effort to investigate the internal structure of the volcanoes with different geophysical techniques, including deep drilling, passive and active seismic tomography, geoelectrics and magnetotellurics and gravimetry. One of the limits of conventional geophysical methods is the spatial resolution, which typically ranges between some tens of meters up to 1 km. In this sense, the radiography of active volcanoes based on natural muons, even if limited to the external part of the volcano, represents an important tool for investigating the internal structure of a volcano at higher spatial resolution (Macedonio and Martini, 2009). Moreover, muon radiography is able to resolve density contrasts of the order of 1-3%, significantly greater than the resolution obtained with conventional methods. As example, the experiment of muon radiography carried out at Mt. Asama volcano by Tanaka et al., 2007, allowed the reconstruction of the density map of the cone and detection of a dense region that corresponds to the position and shape of a lava deposit created during the last eruption in 2004. In the framework of a research project financed by the Canary Agency of Research, Innovation and Information Society, we will implement muon measurements at Teide volcano in Tenerife Island and Cumbre Vieja volcano in La Palma Island, Canary Islands, to radiographically image the subsurface structure of these two volcanic edifices. The data analysis will involve the study both of the shallow structure of both volcanoes and of the requirements for the implementation of the muon detectors. Both Cumbre Vieja and Teide are two active volcanoes that arouse great

  19. Application of emulsion imaging system for cosmic-ray muon radiography to explore the internal structure of Teide and Cumbre Vieja volcanoes in the Canary Islands, Spain

    NASA Astrophysics Data System (ADS)

    Hernández, Iñigo; Hernández, Pedro; Pérez, Nemesio; Tanaka, Hiroyuki; Miyamoto, Seygo; Barrancos, José; Padrón, Eleazar

    2013-04-01

    The internal structure of volcanoes, especially in their up per part, is product of past eruptions. Therefore, the knowledge of the internal structure of a volcano is of great importance for understanding its behaviour and to forecast the nature and style of the next eruptions. For these reasons, during past years scientists have made a big effort to investigate the internal structure of the volcanoes with different geophysical techniques, including deep drilling, passive and active seismic tomography, geoelectrics and magnetotellurics and gravimetry. One of the limits of conventional geophysical methods is the spatial resolution, which typically ranges between some tens of meters up to 1 km. In this sense, the radiography of active volcanoes based on natural muons, even if limited to the external part of the volcano, represents an important tool for investigating the internal structure of a volcano at higher spatial resolution (Macedonio and Martini, 2009). Moreover, muon radiography is able to resolve density contrasts of the order of 1-3%, significantly greater than the resolution obtained with conventional methods. As example, the experiment of muon radiography carried out at Mt. Asama volcano by Tanaka et al., 2007, allowed the reconstruction of the density map of the cone and detection of a dense region that corresponds to the position and shape of a lava deposit created during the last eruption in 2004. In the framework of a research project financed by the Canary Agency of Research, Innovation and Information Society, we will implement muon measurements at Teide volcano in Tenerife Island and Cumbre Vieja volcano in La Palma Island, Canary Islands, to radiographically image the subsurface structure of these two volcanic edifices. The data analysis will involve the study both of the shallow structure of both volcanoes and of the requirements for the implementation of the muon detectors. Both Cumbre Vieja and Teide are two active volcanoes that arouse great

  20. On the time-scales of magmatism at island-arc volcanoes.

    PubMed

    Turner, S P

    2002-12-15

    Precise information on time-scales and rates of change is fundamental to an understanding of natural processes and the development of quantitative physical models in the Earth sciences. U-series isotope studies are revolutionizing this field by providing time information in the range 10(2)-10(4) years, which is similar to that of many modern Earth processes. I review how the application of U-series isotopes has been used to constrain the time-scales of magma formation, ascent and storage beneath island-arc volcanoes. Different elements are distilled-off the subducting plate at different times and in different places. Contributions from subducted sediments to island-arc lava sources appear to occur some 350 kyr to 4 Myr prior to eruption. Fluid release from the subducting oceanic crust into the mantle wedge may be a multi-stage process and occurs over a period ranging from a few hundred kyr to less than one kyr prior to eruption. This implies that dehydration commences prior to the initiation of partial melting within the mantle wedge, which is consistent with recent evidence that the onset of melting is controlled by an isotherm and thus the thermal structure within the wedge. U-Pa disequilibria appear to require a component of decompression melting, possibly due to the development of gravitational instabilities. The preservation of large (226)Ra disequilibria permits only a short period of time between fluid addition and eruption. This requires rapid melt segregation, magma ascent by channelled flow and minimal residence time within the lithosphere. The evolution from basalt to basaltic andesite probably occurs rapidly during ascent or in magma reservoirs inferred from some geophysical data to lie within the lithospheric mantle. The flux across the Moho is broadly andesitic, and some magmas subsequently stall in more shallow crustal-level magma chambers, where they evolve to more differentiated compositions on time-scales of a few thousand years or less.

  1. On the time-scales of magmatism at island-arc volcanoes.

    PubMed

    Turner, S P

    2002-12-15

    Precise information on time-scales and rates of change is fundamental to an understanding of natural processes and the development of quantitative physical models in the Earth sciences. U-series isotope studies are revolutionizing this field by providing time information in the range 10(2)-10(4) years, which is similar to that of many modern Earth processes. I review how the application of U-series isotopes has been used to constrain the time-scales of magma formation, ascent and storage beneath island-arc volcanoes. Different elements are distilled-off the subducting plate at different times and in different places. Contributions from subducted sediments to island-arc lava sources appear to occur some 350 kyr to 4 Myr prior to eruption. Fluid release from the subducting oceanic crust into the mantle wedge may be a multi-stage process and occurs over a period ranging from a few hundred kyr to less than one kyr prior to eruption. This implies that dehydration commences prior to the initiation of partial melting within the mantle wedge, which is consistent with recent evidence that the onset of melting is controlled by an isotherm and thus the thermal structure within the wedge. U-Pa disequilibria appear to require a component of decompression melting, possibly due to the development of gravitational instabilities. The preservation of large (226)Ra disequilibria permits only a short period of time between fluid addition and eruption. This requires rapid melt segregation, magma ascent by channelled flow and minimal residence time within the lithosphere. The evolution from basalt to basaltic andesite probably occurs rapidly during ascent or in magma reservoirs inferred from some geophysical data to lie within the lithospheric mantle. The flux across the Moho is broadly andesitic, and some magmas subsequently stall in more shallow crustal-level magma chambers, where they evolve to more differentiated compositions on time-scales of a few thousand years or less. PMID

  2. The forensics of sub-surface processes on island volcanoes from integrated geodetic observations: results from Tenerife and Montserrat (Invited)

    NASA Astrophysics Data System (ADS)

    Gottsmann, J.

    2009-12-01

    Spatio-temporal variations in geodetic signals at active volcanoes provide important insight on governing subsurface processes. This contribution explores the phenomenology of volcanic unrest and eruptive activity from the perspective of both ground deformation and gravimetric investigations at an ocean island volcanic complex (Tenerife, Canary Islands) and an active andesitic arc volcano (Soufrière Hills volcano [SHV], Montserrat). Despite their marked differences in volcanic evolution and tectonic settings both volcanic systems show remarkable similarities in their subsurface processes. On Tenerife, during unrest in 2004-5, mass movement at depth was quantified by time-lapse gravimetric observations despite the absence of significant ground deformation. Shallow migration of hydrous fluids is identified as the main cause for the unrest marking the reactivation of the central volcanic complex after a century of quiescence. The combination of static and dynamic gravimetric data reveals a causality between the major structural building blocks of the island and the pattern of mass variations. Low density bodies underlie areas of maximum mass variations at the complex. Gravimetric data also indicate that the shallow plumbing system of the 3700 m tall Pico Teide/Pico Viejo composite volcano remained unaffected by the unrest. On Montserrat, time-lapse gravimetric data invoke the existence of a previously unrecognized fault zone beneath the centre of the island that is influenced by changes in stress distribution associated with volcanic activity at SHV. The fault zone either provides a trace for ground water flow or responds to a changed stress field via volcano-tectonic coupling with an elastic opening/closing of fractures. Continuous gravimetric (CG) data enabled the calibration of a new precision tidal model for the island resulting in a reduction of the signal-to-noise ratio by about one order of magnitude. Detided CG records reveal particular gravity perturbations

  3. Experimental constraints on phreatic eruption processes at Whakaari (White Island volcano)

    NASA Astrophysics Data System (ADS)

    Mayer, Klaus; Scheu, Bettina; Gilg, H. Albert; Heap, Michael J.; Kennedy, Ben M.; Lavallée, Yan; Letham-Brake, Mark; Dingwell, Donald B.

    2015-09-01

    Vigorous hydrothermal activity interspersed by sequences of phreatic and phreatomagmatic eruptions occur at Whakaari (White Island volcano), New Zealand. Here, we investigate the influence of sample type (hydrothermally altered cemented ash tuffs and unconsolidated ash/lapilli) and fragmentation mechanism (steam flashing versus gas expansion) on fragmentation and ejection velocities as well as on particle-size and shape. Our rapid decompression experiments show that fragmentation and ejection speeds of two ash tuffs, cemented by alunite and amorphous opal, increase with increasing porosity and that both are significantly enhanced in the presence of steam flashing. Ejection speeds of unconsolidated samples are higher than ejection speeds of cemented tuffs, as less energy is consumed by fragmentation. Fragmentation dominated by steam flashing results in increased fragmentation energy and a higher proportion of fine particles. Particle shape analyses before and after fragmentation reveal that both steam flashing and pure gas expansion produce platy or bladed particles from fracturing parallel to the decompression front. Neither fragmentation mechanisms nor sample type show a significant influence on the shape. Our results emphasize that, under identical pressure and temperature conditions, eruptions accompanied by the process of liquid water flashing to steam are significantly more violent than those driven simply by gas expansion. Therefore, phase changes during decompression and cementation are both important considerations for hazard assessment and modeling of eruptions in hydrothermally active environments.

  4. Barren Island Volcano (NE Indian Ocean): Island-arc high-alumina basalts produced by troctolite contamination

    NASA Astrophysics Data System (ADS)

    Luhr, James F.; Haldar, Dhanapati

    2006-01-01

    Barren Island (BI) is a subduction-related volcanic island lying in the northeastern Indian Ocean, about 750 km north of the northern tip of Sumatra. Rising from a depth of ˜2300 m on the Andaman Sea floor, BI has a submarine volume estimated at ˜400 km 3, but the island is just 3 km across, reaches a maximum elevation of 355 m, and has a subaerial volume of only ˜1.3 km 3. The first historical eruption began in 1787 when a cinder cone grew in the center of a pre-historical caldera 2-km in diameter and sent lava flows westward to reach the sea; activity continued intermittently until 1832. Two subsequent eruptions modified the central cone and also sent lava flows westward to reach the sea in 1991 and 1994-1995. A suite of 28 lava, scoria, and ash samples were investigated from various stages of the subaerial eruptive history of BI. Most are basalts (including all 10 samples from the 1994-1995 eruption) and basaltic andesites (including 7 of 8 samples from the 1991 eruption), but 2 pre-1787 andesites were also studied. On multi-element spider diagrams the BI suite shows subparallel trends for most elements that reflect an important role for fractional crystallization, along with the characteristic depletions of Nb-Ta and enrichments of K-Rb-Pb found in other subduction-related island-arc suites. The typical relative enrichment of Ba is not present, likely because the subducted sediments in the Andaman arc are not Ba-rich. Wide compositional ranges for Cs, Th, Rb, U, and Pb may trace different degrees of scavenging from the underlying volcanic pile. BI basalts and basaltic andesites have variable abundances of phenocrystic-microphenocrystic olivine plus Cr-Al-Mg spinel inclusions, plagioclase, and clinopyroxene, embedded in a matrix of glass, the same minerals, and titanomagnetite (mostly exsolved). The most remarkable mineralogical feature of certain BI basalts and basaltic andesites is the presence of abundant (to 40 vol.%) and large (to 5 mm) crystals of

  5. Hazard communication by the Alaska Volcano Observatory Concerning the 2008 Eruptions of Okmok and Kasatochi Volcanoes, Aleutian Islands, Alaska

    NASA Astrophysics Data System (ADS)

    Adleman, J. N.; Cameron, C. E.; Neal, T. A.; Shipman, J. S.

    2008-12-01

    The significant explosive eruptions of Okmok and Kasatochi volcanoes in 2008 tested the hazard communication systems at the Alaska Volcano Observatory (AVO) including a rigorous test of the new format for written notices of volcanic activity. AVO's Anchorage-based Operations facility (Ops) at the USGS Alaska Science Center serves as the hub of AVO's eruption response. From July 12 through August 28, 2008 Ops was staffed around the clock (24/7). Among other duties, Ops staff engaged in communicating with the public, media, and other responding federal and state agencies and issued Volcanic Activity Notices (VAN) and Volcano Observatory Notifications for Aviation (VONA), recently established and standardized products to announce eruptions, significant activity, and alert level and color code changes. In addition to routine phone communications with local, national and international media, on July 22, AVO held a local press conference in Ops to share observations and distribute video footage collected by AVO staff on board a U.S. Coast Guard flight over Okmok. On July 27, AVO staff gave a public presentation on the Okmok eruption in Unalaska, AK, 65 miles northeast of Okmok volcano and also spoke with local public safety and industry officials, observers and volunteer ash collectors. AVO's activity statements, photographs, and selected data streams were posted in near real time on the AVO public website. Over the six-week 24/7 period, AVO staff logged and answered approximately 300 phone calls in Ops and approximately 120 emails to the webmaster. Roughly half the logged calls were received from interagency cooperators including NOAA National Weather Service's Alaska Aviation Weather Unit and the Center Weather Service Unit, both in Anchorage. A significant number of the public contacts were from mariners reporting near real-time observations and photos of both eruptions, as well as the eruption of nearby Cleveland Volcano on July 21. As during the 2006 eruption of

  6. Volcano-Tectonic History of the Island of Montserrat, West Indies, From Seismic Reflection Profiles

    NASA Astrophysics Data System (ADS)

    Kenedi, C. L.; Sparks, S. J.; Dean, S.; Hammond, J.; Malin, P. E.; Minshull, T.; Paulatto, M.; Peirce, C.; Ryan, G.; Shalev, E.; Voight, B.

    2008-12-01

    Seismic reflection profiles provide a cross-sectional view of crustal layers and thus details about local sedimentation rates, chronology, and depositional materials. Based on seismic profiles collected as part of the SEA-CALIPSO seismic experiment, we apply this method to interpreting the volcanic and local tectonic history of the island of Montserrat, in the Lesser Antilles arc. In December 2007, the vessel RRS James Cook towed a tuned, 2600 cubic inch, 8-airgun array along encircling and radial lines around Montserrat. The airguns fired every 60 sec (approx. every 140 m) at a pressure of 2000 psi. The ship also towed a 600 m streamer consisting of 48 hydrophone channels. Over a period of 77 hours, the hydrophones recorded a total of 4414 shots. Onboard the ship, data were stacked to produce 26 seismic profiles. The profiles vary in length up to 15 km and allow interpretation up to a depth of approx. 2.5 km. The profiles from east of Montserrat reveal fans of coarse-grained debris flows and submarine pyroclastic flows that derive from both the older volcanic centers and the active Soufriere Hills Volcano (SHV). The flows form tapering wedges that have been overlain by younger sea-floor sediments. Older ( > 1 Ma) sedimentary rocks, containing multiple reflective layers, deflect downwards towards and beneath Montserrat, forming a moat into which the debris and pyroclastic flows have deposited. A sub-sediment volcanic basement is present offshore at approximately 1.5 km depth. Offshore on the west side of the island the prominent Belham valley fault can be traced trending NW. The new data suggest that the fault line has been active in the recent geological past; the fault has offset submarine deposits offshore and tectonic blocks onshore (Garibaldi Hill, St. Georges Hill, Roches Bluff), has caused the down-warping of ocean sediments on the east side of the island, and likely influenced the location of domes and feeding conduits at and adjacent to the SHV. Montserrat

  7. Infrasonic monitoring of the eruption at a remote island volcano, Nishino-shima

    NASA Astrophysics Data System (ADS)

    Ichihara, Mie; Kikuchi, Junji; Nishida, Kiwamu; Sugioka, Hiroko; Hamano, Yozo

    2016-04-01

    Nishino-shima volcano in some 1000 km south of Tokyo is active since November, 2013. The new island has grown to almost swallow the original Nishino-shima island. We installed infrasonic stations to Chichi-jima, which is the closest inhabited island in 130 km to the east of Nishino-shima, and have been detecting clear infrasonic signals from the direction of Nishino-shima since May 2014. We also conducted infrasonic and visual observation in the research cruise close to Nishino-shima on 26th and 27th of February, 2015. The data was compared with the infrasonic data recorded at Chichi-jima to confirm that infrasound associated with the Strombolian activity of Nishino-shima was recorded at the distance of 130 km. The detection of infrasound at such a distance obviously depends on the atmospheric structure. Here we present a simple method to evaluate the atmospheric effect, which is crucial for interpreting the infrasonic observation to the change of volcanic activity. The method is similar to the Monte Carlo phonon method proposed by Shearer and Earle (2004) to investigate seismic scattering wave fields. A million phonon particles were transmitted from the ground to the atmosphere in random angles in 45 degrees from the horizontal direction. Ray-tracing calculation (Tahira, 1982) was performed for each particles assuming one dimensional atmospheric structure with the effect of wind advection in the plane. We counted the number of the particles that reached Chichi-jima in the area of the infrasound stations spanning about 1 km, and regarded that the number represented the infrasound energy that reached the stations. Perfect reflection was assumed on the sea surface, but the particles that were trapped in the bottom layer thinner than the scale of the infrasonic wave length were eliminated. The calculation was performed for atmospheric structures from May 2014 to December 2015, using the data from radiosonde measurements twice a day by the Japan Meteorology Agency. The

  8. Hydrogeochemical, Stable Isotopes and Hydrology of Fogo Volcano Perched Aquifers: São Miguel Island, Azores (Portugal)

    NASA Astrophysics Data System (ADS)

    Antunes, P. C.; Boutt, D. F.; Martini, A. M.; Ferstad, J.; Rodrigues, F. C.

    2012-12-01

    Fogo Volcano is located at central part of São Miguel Island and corresponds to a polygenetic volcano with a caldera made by an intercalated accumulation of volcaniclastic deposits and lava flows. São Miguel Island is one of the nine volcanic islands that form the Azores Archipelago. The volcano is 950 meters high, with a caldera diameter of 3.2 Km, which holds a lake inside. The last eruption occurred in 1563-1564, as one of a group of seven traquitic eruptions occurring within the last 5000 years. The volcanic activity is related to hydrothermal activity in a geothermal field located in the volcanoes North flank. The hydrology of Fogo Volcano is characterized by a series of perched-water bodies drained by a large number of springs grouped at different altitudes on the volcano flanks. It is possible to identify three types of water (1) Fresh water, cold temperature (12 - 17 C) with low dissolved solids contents (average conductivity of 179 μS/cm), pH range between 6.60 and 7.82, dominated by the major ions Na, K, HCO3, and Cl, and correspond mainly to sodium bicarbonate type water. (2) Mineral water, cold temperature (12.5 - 19.4 C) with low dissolved solids contents (average conductivity of 261 μS/cm), acid pH range between 4.62 and 6.79, and correspond mainly to sodium bicarbonate type water. (3) Thermal water, with temperature of 32 C, high dissolved solids content (4.62 mS/cm), with a pH around 4.50 and belongs to sodium sulfate type water. South Fogo volcano have only fresh water springs and at high elevation, springs drained from pumice fall deposits near 700 m of altitude. Water dissolved solids contents increased slightly with springs at lower altitude due to water-rock interaction. Springs sampled around 700 m high have a conductivity average of 85 μS/cm, at 520 m an average of 129 μS/cm, at 430 m an average of 182 μS/cm, at 200 m an average of 192 μS/cm and at 12 m high sea level and average of 472 μS/cm. This trend is observed at North Fogo

  9. Sar interferometry time series analysis of surface deformation for Piton de la Fournaise volcano, Reunion Island

    NASA Astrophysics Data System (ADS)

    Chen, Yu; Remy, Dominique; Froger, Jean-Luc; Darrozes, José; Bonvalot, Sylvain

    2015-04-01

    Piton de la Fournaise, located on the south-eastern side of Réunion Island in the Indian Ocean, is a hotspot oceanic basaltic shield volcano whose activity began more than 500,000 years ago. It is one of the most active volcanoes in the world with a high eruptive frequency on average one eruption every 9 months since 1998. In April 2007, Piton de la Fournaise experienced an exceptional eruption which is considered as the largest historical eruption ever observed during the 20th and 21th centuries, characterized by an effusion of 210 ×106 m3 volume of lava with a 340 m consequent collapse of the Dolomieu crater and the onset of a landslide on the eastern flank. ENVISAT and ALOS data analysis showed that the subsidence of central cone and landslide of eastern flank continued deforming after this eruption at least until June 2008, but no clear ground deformation has been detected after this date from Band-C or Band-L radar images. We so perform a detailed spatio-temporal analysis of ground motions on Piton de la Fournaise using X-band InSAR time series acquired from 2009 to 2014. X-Band was chosen because it provides high spatial resolution (up to 1 m), short revisit period (minimum 11 days) and a highest sensibility to ground deformation. Our large dataset of X-band radar images is composed of 106 COSMO-SkyMed and 96 TerraSAR-X Single-Look Complex images acquired in ascending and descending orbits. The interferograms were generated using DORIS. A high resolution reference Digital Elevation Model (DEM) (5m x 5m Lidar DEM) was used to model and remove the topographic contribution from the interferograms. We employed next StaMPS/MTI (Hooper et al., 2012) to generate the displacement time series and we analyzed the time-dependant behavior of surface displacement using a principal component analysis (PCA) decomposition. This analysis clearly reveals that the large eastward motion affecting the eastern flank of Piton de la Fournaise remained active (LOS velocity of about

  10. Ups and downs on spreading flanks of ocean-island volcanoes: evidence from Mauna Loa and Kīlauea

    USGS Publications Warehouse

    Lipman, Peter W.; Eakins, Barry W.; Yokose, Hisayoshi

    2003-01-01

    Submarine-flank deposits of Hawaiian volcanoes are widely recognized to have formed largely by gravitationally driven volcano spreading and associated landsliding. Observations from submersibles show that prominent benches at middepths on flanks of Mauna Loa and Kilauea consist of volcaniclastic debris derived by landsliding from nearby shallow submarine and subaerial flanks of the same edifice. Massive slide breccias from the mature subaerial tholeiitic shield of Mauna Loa underlie the frontal scarp of its South Kona bench. In contrast, coarse volcaniclastic sediments derived largely from submarine-erupted preshield alkalic and transitional basalts of ancestral Kilauea underlie its Hilina bench. Both midslope benches record the same general processes of slope failure, followed by modest compression during continued volcano spreading, even though they record development during different stages of edifice growth. The dive results suggest that volcaniclastic rocks at the north end of the Kona bench, interpreted by others as distal sediments from older volcanoes that were offscraped, uplifted, and accreted to the island by far-traveled thrusts, alternatively are a largely coherent stratigraphic assemblage deposited in a basin behind the South Kona bench.

  11. Characteristics of Offshore Hawai';i Island Seismicity and Velocity Structure, including Lo';ihi Submarine Volcano

    NASA Astrophysics Data System (ADS)

    Merz, D. K.; Caplan-Auerbach, J.; Thurber, C. H.

    2013-12-01

    The Island of Hawai';i is home to the most active volcanoes in the Hawaiian Islands. The island's isolated nature, combined with the lack of permanent offshore seismometers, creates difficulties in recording small magnitude earthquakes with accuracy. This background offshore seismicity is crucial in understanding the structure of the lithosphere around the island chain, the stresses on the lithosphere generated by the weight of the islands, and how the volcanoes interact with each other offshore. This study uses the data collected from a 9-month deployment of a temporary ocean bottom seismometer (OBS) network fully surrounding Lo';ihi volcano. This allowed us to widen the aperture of earthquake detection around the Big Island, lower the magnitude detection threshold, and better constrain the hypocentral depths of offshore seismicity that occurs between the OBS network and the Hawaii Volcano Observatory's land based network. Although this study occurred during a time of volcanic quiescence for Lo';ihi, it establishes a basis for background seismicity of the volcano. More than 480 earthquakes were located using the OBS network, incorporating data from the HVO network where possible. Here we present relocated hypocenters using the double-difference earthquake location algorithm HypoDD (Waldhauser & Ellsworth, 2000), as well as tomographic images for a 30 km square area around the summit of Lo';ihi. Illuminated by using the double-difference earthquake location algorithm HypoDD (Waldhauser & Ellsworth, 2000), offshore seismicity during this study is punctuated by events locating in the mantle fault zone 30-50km deep. These events reflect rupture on preexisting faults in the lower lithosphere caused by stresses induced by volcano loading and flexure of the Pacific Plate (Wolfe et al., 2004; Pritchard et al., 2007). Tomography was performed using the double-difference seismic tomography method TomoDD (Zhang & Thurber, 2003) and showed overall velocities to be slower than

  12. Long term volcano monitoring by using advanced Persistent Scatterer SAR Interferometry technique: A case study at Unimak Island, Alaska

    NASA Astrophysics Data System (ADS)

    Gong, W.; Meyer, F. J.; Freymueller, J. T.; Lu, Z.

    2012-12-01

    Unimak Island, the largest island in the eastern Aleutians of Alaska, is home to three major active volcanoes: Shishaldin, Fisher, and Westdahl. Shishaldin and Westdahl erupted within the past 2 decades and Fisher has shown persistent hydrothermal activity (Mann and Freymueller, 2003). Therefore, Unimak Island is of particular interest to geoscientists. Surface deformation on Unimak Island has been studied in several previous efforts. Lu et al. (2000, 2003) applied conventional InSAR techniques to study surface inflation at Westdahl during 1991 and 2000. Mann and Freymueller (2003) used GPS measurements to analyze inflation at Westdahl and subsidence at Fisher during 1998-2001. Moran et al., ( 2006) reported that Shishaldin, the most active volcano in the island , experienced no significant deformation during the 1993 to 2003 period bracketing two eruptions. In this paper, we present deformation measurements at Unimak Islank during 2003-2010 using advanced persistent scatterer InSAR (PSI). Due to the non-urban setting in a subarctic environment and the limited data acquisition, the number of images usable for PSI processing is limited to about 1-3 acquisitions per year. The relatively smaller image stack and the irregular acquisition distribution in time pose challenges in the PSI time-series processing. Therefore, we have developed a modified PSI technique that integrates external atmospheric information from numerical weather predication models to assist in the removal of atmospheric artifacts [1]. Deformation modeling based on PSI results will be also presented. Our new results will be combined with previous findings to address the magma plumbing system at Unimak Island. 1) W. Gong, F. J. Meyer (2012): Optimized filter design for irregular acquired data stack in Persistent Scatterers Synthetic Aperture Radar Interferometry, Proceeding of Geosciences and Remote Sensing Symposium (IGARSS), 2012 IEEE International, Munich, Germany.

  13. Seismic monitoring at Deception Island volcano (Antarctica): the 2010-2011 survey

    NASA Astrophysics Data System (ADS)

    Martín, R.; Carmona, E.; Almendros, J.; Serrano, I.; Villaseñor, A.; Galeano, J.

    2012-04-01

    As an example of the recent advances introduced in seismic monitoring of Deception Island volcano (Antarctica) during recent years, we describe the instrumental network deployed during the 2010-2011 survey by the Instituto Andaluz de Geofísica of University of Granada, Spain (IAG-UGR). The period of operation extended from December 19, 2010 to March 5, 2011. We deployed a wireless seismic network composed by four three-component seismic stations. These stations are based on 24-bit SL04 SARA dataloggers sampling at 100 sps. They use a PC with embedded linux and SEISLOG data acquisition software. We use two types of three-component seismometers: short-period Mark L4C with natural frequency of 1 Hz and medium-period Lennartz3D/5s with natural frequency of 0.2 Hz. The network was designed for an optimum spatial coverage of the northern half of Deception, where a magma chamber has been reported. Station locations include the vicinity of the Spanish base "Gabriel de Castilla" (GdC), Obsidianas Beach, a zone near the craters from the 1970 eruptions, and the Chilean Shelter located south of Pendulum Cove. Continuous data from the local seismic network are received in real-time in the base by wifi transmission. We used Ubiquiti Networks Nanostation2 antennas with 2.4 GHz, dual-polarity, 10 dBi gain, and 54 Mbps transmission rate. They have shown a great robustness and speed for real-time applications. To prioritize data acquisition when the battery level is low, we have designed a circuit that allows independent power management for the seismic station and wireless transmission system. The reception antenna located at GdC is connected to a computer running SEISCOMP. This software supports several transmission protocols and manages the visualization and recording of seismic data, including the generation of summary plots to show the seismic activity. These twelve data channels are stored in miniseed format and displayed in real time, which allows for a rapid evaluation of

  14. SAR-based Estimation of Glacial Extent and Velocity Fields on Isanotski Volcano, Aleutian Islands, Alaska

    NASA Astrophysics Data System (ADS)

    Sousa, D.; Lee, A.; Parker, O. P.; Pressler, Y.; Guo, S.; Osmanoglu, B.; Schmidt, C.

    2012-12-01

    Global studies show that Earth's glaciers are losing mass at increasing rates, creating a challenge for communities that rely on them as natural resources. Field observation of glacial environments is limited by cost and inaccessibility. Optical remote sensing is often precluded by cloud cover and seasonal darkness. Synthetic aperture radar (SAR) overcomes these obstacles by using microwave-frequency electromagnetic radiation to provide high resolution information on large spatial scales and in remote, atmospherically obscured environments. SAR is capable of penetrating clouds, operating in darkness, and discriminating between targets with ambiguous spectral signatures. This study evaluated the efficacy of two SAR Earth observation methods on small (< 7 km2) glaciers in rugged topography. The glaciers chosen for this study lie on Isanotski Volcano in Unimak Island, Aleutian Archipelago, USA. The local community on the island, the City of False Pass, relies on glacial melt for drinking water and hydropower. Two methods were used: (1) velocity field estimation based on Repeat Image Feature Tracking (RIFT) and (2) glacial boundary delineation based on interferometric coherence mapping. NASA Uninhabited Aerial Vehicle SAR (UAVSAR) single-polarized power images and JAXA Advanced Land Observing Satellite Phased Array type L-band SAR (ALOS PALSAR) single-look complex images were analyzed over the period 2008-2011. UAVSAR image pairs were coregistered to sub-pixel accuracy and processed with the Coregistration of Optically Sensed Images and Correlation (COSI-Corr) feature tracking module to derive glacial velocity field estimates. Maximum glacier velocities ranged from 28.9 meters/year to 58.3 meters/year. Glacial boundaries were determined from interferometric coherence of ALOS PALSAR data and subsequently refined with masking operations based on terrain slope and segment size. Accuracy was assessed against hand-digitized outlines from high resolution UAVSAR power images

  15. Fluxes of magmatic chlorine and sulfur from volcano-hydrothermal systems. Examples for Northern Kuril Islands Paramushir and Shiashkotan.

    NASA Astrophysics Data System (ADS)

    Kalacheva, Elena; Taran, Yuri

    2015-04-01

    The total flux of components degassed from the magma through persistently degassing volcanoes comprises of the volcanic vapor flux from fumaroles to the atmosphere, diffuse flux through volcanic slopes and the hydrothermal flux to the local hydrologic network. The hydrothermal flux may be provided by the discharge of fluids formed at depth over the magma body and/or by acid waters which are formed by the absorption of the ascending volcanic vapor by shallow ground. The anion composition (Cl and SO4) of the discharging thermal waters from a volcano-hydrothermal system originates from the volcanic vapor and should be taken into account in estimations of the magmatic volatile output and volatile recycling in subduction zones. Here we report the chemical (major and trace elements) and isotopic composition of acidic and neutral thermal waters, chemical and isotopic composition of volcanic vapors and solute fluxes from the northern Kurilian islands Paramushir (Ebeko volcanic center) and Shiashkotan (volcanoes Sinarka and Kuntomintar). The total measured outputs of chloride and sulfur from the system in 2006-2014 were estimated on average as 730 g/s and 980 g/s, respectively, which corresponds to the equivalent fluxes of 64 t/d of HCl and 169 t/d of SO2. These values are one order of magnitude higher than the fumarolic output of Cl and S from the low-temperature fumarolic field of Ebeko (<120°C). The estimated discharge rate of hot (85°C) water from the system with ~ 3500 ppm of chloride is about 0.3 m3s-1 which is among the highest hot water natural outputs ever measured for a volcano-hydrothermal system. The total hydrothermal discharge of Cl and S from Shiashkotan island to the Sea of Okhotsk associated with magmatic activity of two volcanoes is estimated as ca. 20 t/d and 40 t/d, respectively, which is close to the fumarolic output from both volcanoes (Sinarka and Kuntomintar) estimated using the chemistry and flow rates of fumaroles those measured temperature is

  16. 40Ar/39Ar geochronology of subaerial lava flows of Barren Island volcano and the deep crust beneath the Andaman Island Arc, Burma Microplate

    NASA Astrophysics Data System (ADS)

    Ray, Jyotiranjan S.; Pande, Kanchan; Bhutani, Rajneesh

    2015-06-01

    Little was known about the nature and origin of the deep crust beneath the Andaman Island Arc in spite of the fact that it formed part of the highly active Indonesian volcanic arc system, one of the important continental crust forming regions in Southeast Asia. This arc, formed as a result of subduction of the Indian Plate beneath the Burma Microplate (a sliver of the Eurasian Plate), contains only one active subaerial magmatic center, Barren Island volcano, whose evolutional timeline had remained uncertain. In this work, we present results of the first successful attempt to date crustal xenoliths and their host lava flows from the island, by incremental heating 40Ar/39Ar method, in an attempt to understand the evolutionary histories of the volcano and its basement. Based on concordant plateau and isochron ages, we establish that the oldest subaerial lava flows of the volcano are 1.58 ± 0.04 (2σ) Ma, and some of the plagioclase xenocrysts have been derived from crustal rocks of 106 ± 3 (2σ) Ma. Mineralogy (anorthite + Cr-rich diopside + minor olivine) and isotopic compositions (87Sr/86Sr < 0.7040; ɛNd > 7.0) of xenoliths not only indicate their derivation from a lower (oceanic) crustal olivine gabbro but also suggest a genetic relationship between the arc crust and the ophiolitic basement of the Andaman accretionary prism. We speculate that the basements of the forearc and volcanic arc of the Andaman subduction zone belong to a single continuous unit that was once attached to the western margin of the Eurasian Plate.

  17. Enhancement of sub-daily positioning solutions for surface deformation monitoring at Deception volcano (South Shetland Islands, Antarctica)

    NASA Astrophysics Data System (ADS)

    Prates, G.; Berrocoso, M.; Fernández-Ros, A.; García, A.

    2013-02-01

    Deception Island is one of the most visited places in Antarctica. There are biological, geological, and archeological features that are major attractions within Port Foster, its horse shoe-shaped natural inner bay, and two scientific bases that are occupied during austral summers. Deception Island is an active volcano, however, and needs to be monitored in order to reduce risk to people on the island. Surface deformation in response to fluid pressure is one of the main volcanic activities to observe. Automated data acquisition and processing using the global navigation satellite systems allow measurements of surface deformation in near real time. Nevertheless, the positioning repeatability in sub-daily solutions is affected by geophysical influences such as ocean tidal loading, among others. Such periodic influences must be accurately modeled to achieve similar repeatability as daily solutions that average them. However, a single solution each 24 h will average out the deformation suffered during that period, and the position update waiting time can be a limitation for near real-time purposes. Throughout the last five austral summer campaigns in Deception, using simultaneous wireless communications between benchmarks, a processing strategy was developed to achieve millimeter-level half-hourly positioning solutions that have similar repeatability as those given by 24-h solutions. For these half-hourly solutions, a tidal analysis was performed to assess any mismodeling of ocean tide loading, and a discrete Kalman filter was designed and implemented to enhance the sub-daily positioning repeatability. With these solutions, the volcano-dynamic activity resulting in localized surface deformation for the last five austral summer campaigns is addressed. Although based on only three carefully located benchmarks, it is shown that Deception has been shortening and subsiding during these last 4 years. The method's accuracy in baselines up to a few hundred kilometers assures

  18. Evidence for enhanced bioavailability of trace elements in the marine ecosystem of Deception Island, a volcano in Antarctica.

    PubMed

    Deheyn, Dimitri D; Gendreau, Philippe; Baldwin, Roberta J; Latz, Michael I

    2005-07-01

    This study assessed whether trace elements present at Deception Island, an active submarine volcano in the Antarctic Peninsula, show enhanced biological availability to the local marine community. Using a weak acid extraction method to dissolve organic material and leach associated but not constitutive trace elements of sediments, fifteen elements were measured from seafloor sediment, seawater particulates, and tissues of benthic (bivalves, brittlestars, sea urchins) and pelagic (demersal and pelagic fishes, krill) organisms collected in the flooded caldera. The highest element concentrations were associated with seafloor sediment, the lowest with seawater particulates and organism tissues. In the case of Ag and Se, concentrations were highest in organism tissue, indicating contamination through the food chain and biomagnification of those elements. The elements Al, Fe, Mn, Sr, Ti, and to a lesser extent Zn, were the most concentrated of the trace elements for all sample types. This indicates that the whole ecosystem of Deception Island is contaminated with trace elements from local geothermal activity, which is also reflected in the pattern of element contamination in organisms. Accordingly, element concentrations were higher in organisms collected at Deception Island compared to those from the neighboring non-active volcanic King George Island, suggesting that volcanic activity enhances bioavailability of trace elements to marine organisms. Trace element concentrations were highest in digestive tissue of organisms, suggesting that elements at Deception Island are incorporated into the marine food web mainly through a dietary route.

  19. Evidence for enhanced bioavailability of trace elements in the marine ecosystem of Deception Island, a volcano in Antarctica.

    PubMed

    Deheyn, Dimitri D; Gendreau, Philippe; Baldwin, Roberta J; Latz, Michael I

    2005-07-01

    This study assessed whether trace elements present at Deception Island, an active submarine volcano in the Antarctic Peninsula, show enhanced biological availability to the local marine community. Using a weak acid extraction method to dissolve organic material and leach associated but not constitutive trace elements of sediments, fifteen elements were measured from seafloor sediment, seawater particulates, and tissues of benthic (bivalves, brittlestars, sea urchins) and pelagic (demersal and pelagic fishes, krill) organisms collected in the flooded caldera. The highest element concentrations were associated with seafloor sediment, the lowest with seawater particulates and organism tissues. In the case of Ag and Se, concentrations were highest in organism tissue, indicating contamination through the food chain and biomagnification of those elements. The elements Al, Fe, Mn, Sr, Ti, and to a lesser extent Zn, were the most concentrated of the trace elements for all sample types. This indicates that the whole ecosystem of Deception Island is contaminated with trace elements from local geothermal activity, which is also reflected in the pattern of element contamination in organisms. Accordingly, element concentrations were higher in organisms collected at Deception Island compared to those from the neighboring non-active volcanic King George Island, suggesting that volcanic activity enhances bioavailability of trace elements to marine organisms. Trace element concentrations were highest in digestive tissue of organisms, suggesting that elements at Deception Island are incorporated into the marine food web mainly through a dietary route. PMID:15649525

  20. The submarine volcano eruption at the island of El Hierro: physical-chemical perturbation and biological response

    PubMed Central

    Fraile-Nuez, E.; González-Dávila, M.; Santana-Casiano, J. M.; Arístegui, J.; Alonso-González, I. J.; Hernández-León, S.; Blanco, M. J.; Rodríguez-Santana, A.; Hernández-Guerra, A.; Gelado-Caballero, M. D.; Eugenio, F.; Marcello, J.; de Armas, D.; Domínguez-Yanes, J. F.; Montero, M. F.; Laetsch, D. R.; Vélez-Belchí, P.; Ramos, A.; Ariza, A. V.; Comas-Rodríguez, I.; Benítez-Barrios, V. M.

    2012-01-01

    On October 10 2011 an underwater eruption gave rise to a novel shallow submarine volcano south of the island of El Hierro, Canary Islands, Spain. During the eruption large quantities of mantle-derived gases, solutes and heat were released into the surrounding waters. In order to monitor the impact of the eruption on the marine ecosystem, periodic multidisciplinary cruises were carried out. Here, we present an initial report of the extreme physical-chemical perturbations caused by this event, comprising thermal changes, water acidification, deoxygenation and metal-enrichment, which resulted in significant alterations to the activity and composition of local plankton communities. Our findings highlight the potential role of this eruptive process as a natural ecosystem-scale experiment for the study of extreme effects of global change stressors on marine environments. PMID:22768379

  1. The submarine volcano eruption at the island of El Hierro: physical-chemical perturbation and biological response.

    PubMed

    Fraile-Nuez, E; González-Dávila, M; Santana-Casiano, J M; Arístegui, J; Alonso-González, I J; Hernández-León, S; Blanco, M J; Rodríguez-Santana, A; Hernández-Guerra, A; Gelado-Caballero, M D; Eugenio, F; Marcello, J; de Armas, D; Domínguez-Yanes, J F; Montero, M F; Laetsch, D R; Vélez-Belchí, P; Ramos, A; Ariza, A V; Comas-Rodríguez, I; Benítez-Barrios, V M

    2012-01-01

    On October 10 2011 an underwater eruption gave rise to a novel shallow submarine volcano south of the island of El Hierro, Canary Islands, Spain. During the eruption large quantities of mantle-derived gases, solutes and heat were released into the surrounding waters. In order to monitor the impact of the eruption on the marine ecosystem, periodic multidisciplinary cruises were carried out. Here, we present an initial report of the extreme physical-chemical perturbations caused by this event, comprising thermal changes, water acidification, deoxygenation and metal-enrichment, which resulted in significant alterations to the activity and composition of local plankton communities. Our findings highlight the potential role of this eruptive process as a natural ecosystem-scale experiment for the study of extreme effects of global change stressors on marine environments. PMID:22768379

  2. Evolution of magma conduits during the 1998-2000 eruptions of Piton de la Fournaise volcano, Réunion Island

    NASA Astrophysics Data System (ADS)

    Fukushima, Y.; Cayol, V.; Durand, P.; Massonnet, D.

    2010-10-01

    At basaltic volcanoes, magma is transported to the surface through dikes (magma-filled fractures), but the evolution of these dikes as eruptions proceed is rarely documented. In March 1998, after five and a half years of quiescence, Piton de la Fournaise volcano (Réunion Island) entered into a new eruptive phase characterized by intense eruptive activity. Coeruptive displacements recorded by interferometric synthetic aperture radar (InSAR) for the first five eruptions of the cycle are analyzed using 3-D boundary element models combined with a Monte Carlo inversion method. We show that the eruptions are associated with the emplacement of lateral dikes rooted at depths of less than about 1000 m, except for the first March 1998 event where an additional deeper source is required. The dikes are located above preeruptive seismic swarms. This is consistent with nearly isotropic stress caused by repeated dike intrusions and low confining pressure enhanced by the presence of pores in the shallowest 1000 m of the edifice. The volumes of the modeled dikes represent 17% of the volume of emitted lava, showing that exogenous growth plays a major role in building the volcano. By taking into account the preeruptive seismicity and tilt data together with the results of InSAR data modeling, we find that dikes first propagate vertically from a source region below sea level before being injected laterally at shallow depth. This behavior is consistent with the presence of levels of neutral buoyancy at shallow depth in the edifice.

  3. Argon geochronology of late Pleistocene to Holocene Westdahl volcano, Unimak Island, Alaska

    USGS Publications Warehouse

    Calvert, Andrew T.; Moore, Richard B.; McGimsey, Robert G.

    2005-01-01

    High-precision 40Ar/39Ar geochronology of selected lavas from Westdahl Volcano places time constraints on several key prehistoric eruptive phases of this large active volcano. A dike cutting old pyroclastic-flow and associated lahar deposits from a precursor volcano yields an age of 1,654+/-11 k.y., dating this precursor volcano as older than early Pleistocene. A total of 11 geographically distributed lavas with ages ranging from 47+/-14 to 127+/-2 k.y. date construction of the Westdahl volcanic center. Lava flows cut by an apparent caldera-rim structure yielded ages of 81+/-5 and 121+/-8 k.y., placing a maximum date of 81 ka on caldera formation. Late Pleistocene and Holocene lavas fill the caldera, but most of them are obscured by the large summit icecap.

  4. Diffuse volcanic degassing and thermal energy release 2015 surveys from the summit cone of Teide volcano, Tenerife (Canary Islands, Spain)

    NASA Astrophysics Data System (ADS)

    Melián, Gladys; Asensio-Ramos, María; Padilla, Germán; Alonso, Mar; Halliwell, Simon; Sharp, Emerson; Butters, Damaris; Ingman, Dylan; Alexander, Scott; Cook, Jenny; Pérez, Nemesio M.

    2016-04-01

    The summit cone of Teide volcano (Spain) is characterized by the presence of a weak fumarolic system, steamy ground, and high rates of diffuse CO2 degassing all around this area. The temperature of the fumaroles (83° C) corresponds to the boiling point of water at discharge conditions. Water is the major component of these fumarolic emissions, followed by CO2, N2, H2, H2S, HCl, Ar, CH4, He and CO, a composition typical of hydrothermal fluids. Previous diffuse CO2 surveys have shown to be an important tool to detect early warnings of possible impending volcanic unrests at Tenerife Island (Melián et al., 2012; Pérez et al., 2013). In July 2015, a soil and fumarole gas survey was undertaken in order to estimate the diffuse volcanic degassing and thermal energy release from the summit cone of Teide volcano. A diffuse CO2 emission survey was performed selecting 170 observation sites according to the accumulation chamber method. Soil CO2 efflux values range from non-detectable (˜0.5 g m-2d-1) up to 10,672 g m-2d-1, with an average value of 601 g m-2d-1. Spatial distribution maps were constructed following the sequential Gaussian simulation (sGs) procedure. Measurement of soil CO2 efflux allowed an estimation of 162 ± 14 t d-1 of deep seated derived CO2. To calculate the steam discharge associated with this volcanic/hydrothermal CO2 output, we used the average H2O/CO2 mass ratio equal to 1.19 (range, 0.44-3.42) as a representative value of the H2O/CO2 mass ratios for Teide fumaroles. The resulting estimate of the steam flow associated with the gas flux is equal to 193 t d-1. The condensation of this steam results in a thermal energy release of 5.0×1011J d-1 for Teide volcano or a total heat flow of 6 MWt. The diffuse gas emissions and thermal energy released from the summit of Teide volcano are comparable to those observed at other volcanoes. Sustained surveillance using these methods will be valuable for monitoring the activity of Teide volcano.

  5. Diffuse volcanic degassing and thermal energy release 2015 surveys from the summit cone of Teide volcano, Tenerife (Canary Islands, Spain)

    NASA Astrophysics Data System (ADS)

    Melián, Gladys; Asensio-Ramos, María; Padilla, Germán; Alonso, Mar; Halliwell, Simon; Sharp, Emerson; Butters, Damaris; Ingman, Dylan; Alexander, Scott; Cook, Jenny; Pérez, Nemesio M.

    2016-04-01

    The summit cone of Teide volcano (Spain) is characterized by the presence of a weak fumarolic system, steamy ground, and high rates of diffuse CO2 degassing all around this area. The temperature of the fumaroles (83° C) corresponds to the boiling point of water at discharge conditions. Water is the major component of these fumarolic emissions, followed by CO2, N2, H2, H2S, HCl, Ar, CH4, He and CO, a composition typical of hydrothermal fluids. Previous diffuse CO2 surveys have shown to be an important tool to detect early warnings of possible impending volcanic unrests at Tenerife Island (Melián et al., 2012; Pérez et al., 2013). In July 2015, a soil and fumarole gas survey was undertaken in order to estimate the diffuse volcanic degassing and thermal energy release from the summit cone of Teide volcano. A diffuse CO2 emission survey was performed selecting 170 observation sites according to the accumulation chamber method. Soil CO2 efflux values range from non-detectable (˜0.5 g m‑2d‑1) up to 10,672 g m‑2d‑1, with an average value of 601 g m‑2d‑1. Spatial distribution maps were constructed following the sequential Gaussian simulation (sGs) procedure. Measurement of soil CO2 efflux allowed an estimation of 162 ± 14 t d‑1 of deep seated derived CO2. To calculate the steam discharge associated with this volcanic/hydrothermal CO2 output, we used the average H2O/CO2 mass ratio equal to 1.19 (range, 0.44-3.42) as a representative value of the H2O/CO2 mass ratios for Teide fumaroles. The resulting estimate of the steam flow associated with the gas flux is equal to 193 t d‑1. The condensation of this steam results in a thermal energy release of 5.0×1011J d‑1 for Teide volcano or a total heat flow of 6 MWt. The diffuse gas emissions and thermal energy released from the summit of Teide volcano are comparable to those observed at other volcanoes. Sustained surveillance using these methods will be valuable for monitoring the activity of Teide volcano.

  6. Debris avalanche triggered by sill intrusions in basaltic volcanoes (Piton des Neiges, La Réunion Island)

    NASA Astrophysics Data System (ADS)

    Berthod, C.; Famin, V.; Bascou, J.; Michon, L.; Ildefonse, B.

    2014-12-01

    Debris avalanches derived from the flanks of volcanic islands are among the largest on Earth. Debris avalanches are rare, catastrophic destabilizations that still keep geologists debating about the mechanisms that initiate them and make them travel huge runout distances. To shed light on the trigger of such destabilizations, we studied the inland scar of a debris avalanche deposit cropping out at Piton des Neiges, a dormant and eroded basaltic volcano of La Réunion Island. The avalanche deposit rests on a pile of 50-70 sill intrusions with a shallow northward dip, i.e. toward the sea. We measured the anisotropy of magnetic susceptibility in a transect across the uppermost sill of the pile in contact with the avalanche deposit. This transect reveals a strongly asymmetric magnetic fabric, consistent with a north-directed shear movement of the upper intrusion wall. This suggests that the upper sill induced a co-intrusive shear displacement of the volcano flank toward the sea. The upper sill margin in contact with the avalanche is striated, showing that this intrusion is older than the avalanche. Striae indicate a northward direction of avalanche runout. The upper sill margin also displays a magmatic lineation consistent with a magma flow in the intrusion toward the north. There is thus a striking kinematic consistency between the directions of intrusion propagation and avalanche runout, both oriented toward the sea. From the above results, we propose that repeated sill intrusions, such as observed on Piton des Neiges, increase the instability of a volcanic edifice. Each injection induces an incremental slip of the overlying rock mass, which may eventually end up into a landslide. Sill intrusions associated with seaward displacements of volcano flank, such as inferred for the April 2007 eruption of Piton de la Fournaise (also in La Réunion), should therefore be considered as a potential trigger of debris avalanches.

  7. Shallow submarine volcano group in the early stage of island arc development: Geology and petrology of small islands south off Hahajima main island, the Ogasawara Islands

    NASA Astrophysics Data System (ADS)

    Kanayama, Kyoko; Umino, Susumu; Ishizuka, Osamu

    2014-05-01

    Small Islands south off Hahajima, the southernmost of the Ogasawara Archipelago, consist of primitive basalts (<12 wt.% MgO) to dacite erupted during the transitional stage immediately following boninite volcanism on the incipient arc to sustained typical oceanic arc. Strombolian to Hawaiian fissure eruptions occurring on independent volcanic centers for the individual islands under a shallow sea produced magnesian basalt to dacite fall-out tephras, hyaloclastite and a small volume of pillow lava, which were intruded by NE-trending dikes. These volcanic strata are correlated to the upper part (<40 Ma) of the Hahajima main island. Volcanic rock samples have slightly lower FeO*/MgO ratios than the present volcanic front lavas, and are divided into three types with high, medium and low La/Yb ratios. Basalt to dacite of high- and medium-La/Yb types show both tholeiitic (TH) and calc-alkaline (CA) differentiation trends. Low-La/Yb type belongs only to TH basalt. The multiple magma types are coexistence on the each island. TH basalts have phenocrysts of olivine, clinopyroxene and plagioclase, while CA basalts are free from plagioclase phenocrysts.

  8. Controlled-source seismic investigations of the crustal structure beneath Erebus volcano and Ross Island, Antarctica: Preliminary Results

    NASA Astrophysics Data System (ADS)

    Maraj, S.; Kyle, P. R.; Zandomeneghi, D.; Knox, H. A.; Aster, R. C.; Snelson, C. M.; Miller, P. E.; Kaip, G. M.

    2009-12-01

    During the 2008-09 Austral summer field season we undertook a controlled-source seismic experiment (Tomo-Erebus, TE) to examine the shallow magmatic system beneath the active Erebus volcano (TE-3D) and the crustal structure beneath Ross Island. Here we report on the TE-2D component, which was designed to produce a two-dimensional P-wave velocity model along an east-west profile across Ross Island. Marine geophysical observations near Ross Island have identified the north-south trending Terror Rift within the older and broader Victoria Land Basin, which are a component of the intraplate West Antarctic Rift System. Mount Erebus and Ross Island are circumstantially associated with the Terror Rift and its thin (~20 km) crust. The nature, extent and role of the Terror Rift in controlling the evolution of Ross Island volcanism and the on-going eruptive activity of Erebus volcano are unknown. In TE-2D, we deployed 21 seismic recorders (Ref Tek 130) with three-component 4.5 Hz geophones (Sercel L-28-3D) along a 90-km east-west line between Capes Royds and Crozier. These were supplemented by 79 similar instruments deployed for the high-resolution TE-3D experiment within a 3 x 3 km grid around the summit crater of Erebus, an array of 8 permanent short period and broadband sensors used to monitor the activity of Erebus and 23 three-component sensors (Guralp CMG-40T, 30s-100 Hz) positioned around the flanks and summit of Erebus. Fifteen chemical sources were loaded in holes drilled about 15 m deep in the snow and ice. The size of these shots ranged from 75 to 600 kg of ANFO with the largest shots at the ends of the profile. An additional shot was detonated in the sea (McMurdo Sound) using 200 kg of dynamite. Due to the rugged terrain, short field seasons and large area to be covered, the seismometer spacing along the TE-2D profile is quite large (~ 5 km spacing), resulting in poor near-surface data resolution. However, the data have a high signal to noise ratio with clear

  9. Solomon's Sea and [Pi

    ERIC Educational Resources Information Center

    Simoson, Andrew J.

    2009-01-01

    This paper is a whimsical survey of the various explanations which might account for the biblical passage in I Kings 7:23 that describes a round object--a bronze basin called Solomon's Sea--as having diameter ten cubits and circumference thirty cubits. Can the biblical pi be any number other than 3? We offer seven different perspectives on this…

  10. Imaging spatial and temporal seismic source variations at Sierra Negra Volcano, Galapagos Islands using back-projection methods

    NASA Astrophysics Data System (ADS)

    Kelly, C. L.; Lawrence, J. F.; Ebinger, C. J.

    2013-12-01

    Imaging spatial and temporal seismic source variations at Sierra Negra Volcano, Galapagos Islands using back-projection methods Cyndi Kelly1, Jesse F. Lawrence1, Cindy Ebinger2 1Stanford University, Department of Geophysics, 397 Panama Mall, Stanford, CA 94305, USA 2University of Rochester, Department of Earth and Environmental Science, 227 Hutchison Hall, Rochester, NY 14627, USA Low-magnitude seismic signals generated by processes that characterize volcanic and hydrothermal systems and their plumbing networks are difficult to observe remotely. Seismic records from these systems tend to be extremely 'noisy', making it difficult to resolve 3D subsurface structures using traditional seismic methods. Easily identifiable high-amplitude bursts within the noise that might be suitable for use with traditional seismic methods (i.e. eruptions) tend to occur relatively infrequently compared to the length of an entire eruptive cycle. Furthermore, while these impulsive events might help constrain the dynamics of a particular eruption, they shed little insight into the mechanisms that occur throughout an entire eruption sequence. It has been shown, however, that the much more abundant low-amplitude seismic 'noise' in these records (i.e. volcanic or geyser 'tremor') actually represents a series of overlapping low-magnitude displacements that can be directly linked to magma, fluid, and volatile movement at depth. This 'noisy' data therefore likely contains valuable information about the processes occurring in the volcanic or hydrothermal system before, during and after eruption events. In this study, we present a new method to comprehensively study how the seismic source distribution of all events - including micro-events - evolves during different phases of the eruption sequence of Sierra Negra Volcano in the Galapagos Islands. We apply a back-projection search algorithm to image sources of seismic 'noise' at Sierra Negra Volcano during a proposed intrusion event. By analyzing

  11. Volcanic sulfur dioxide index and volcanic explosivity index inferred from eruptive volume of volcanoes in Jeju Island, Korea: application to volcanic hazard mitigation

    NASA Astrophysics Data System (ADS)

    Ko, Bokyun; Yun, Sung-Hyo

    2016-04-01

    Jeju Island located in the southwestern part of Korea Peninsula is a volcanic island composed of lavaflows, pyroclasts, and around 450 monogenetic volcanoes. The volcanic activity of the island commenced with phreatomagmatic eruptions under subaqueous condition ca. 1.8-2.0 Ma and lasted until ca. 1,000 year BP. For evaluating volcanic activity of the most recently erupted volcanoes with reported age, volcanic explosivity index (VEI) and volcanic sulfur dioxide index (VSI) of three volcanoes (Ilchulbong tuff cone, Songaksan tuff ring, and Biyangdo scoria cone) are inferred from their eruptive volumes. The quantity of eruptive materials such as tuff, lavaflow, scoria, and so on, is calculated using a model developed in Auckland Volcanic Field which has similar volcanic setting to the island. The eruptive volumes of them are 11,911,534 m3, 24,987,557 m3, and 9,652,025 m3, which correspond to VEI of 3, 3, and 2, respectively. According to the correlation between VEI and VSI, the average quantity of SO2 emission during an eruption with VEI of 3 is 2-8 × 103 kiloton considering that the island was formed under intraplate tectonic setting. Jeju Island was regarded as an extinct volcano, however, several studies have recently reported some volcanic eruption ages within 10,000 year BP owing to the development in age dating technique. Thus, the island is a dormant volcano potentially implying high probability to erupt again in the future. The volcanoes might have explosive eruptions (vulcanian to plinian) with the possibility that SO2 emitted by the eruption reaches stratosphere causing climate change due to backscattering incoming solar radiation, increase in cloud reflectivity, etc. Consequently, recommencement of volcanic eruption in the island is able to result in serious volcanic hazard and this study provides fundamental and important data for volcanic hazard mitigation of East Asia as well as the island. ACKNOWLEDGMENTS: This research was supported by a grant [MPSS

  12. High-K andesite petrogenesis and crustal evolution: Evidence from mafic and ultramafic xenoliths, Egmont Volcano (Mt. Taranaki) and comparisons with Ruapehu Volcano, North Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Price, Richard C.; Smith, Ian E. M.; Stewart, Robert B.; Gamble, John A.; Gruender, Kerstin; Maas, Roland

    2016-07-01

    This study uses the geochemistry and petrology of xenoliths to constrain the evolutionary pathways of host magmas at two adjacent andesitic volcanoes in New Zealand's North Island. Egmont (Mt. Taranaki) is located on the west coast of the North Island and Ruapehu lies 140 km to the east at the southern end of the Taupo Volcanic Zone, the principal locus of subduction-related magmatism in New Zealand. Xenoliths are common in the eruptives of both volcanoes but the xenoliths suites are petrographically and geochemically different. Ruapehu xenoliths are predominantly pyroxene-plagioclase granulites derived from Mesozoic meta-greywacke basement and the underlying oceanic crust. The xenolith population of Egmont Volcano is more complex. It includes sedimentary, metamorphic and plutonic rocks from the underlying basement but is dominated by coarse grained, mafic and ultramafic igneous rocks. Gabbroic xenoliths (Group 1) are composed of plagioclase, clinopyroxene and amphibole whereas ultramafic xenoliths are dominated by amphibole (Group 2) or pyroxene (Group 3) or, in very rare cases, olivine (Group 4). In Group 1 xenoliths plagioclase and clinopyroxene and in some cases amphibole show cumulate textures. Amphibole also occurs as intercumulate poikilitic crystals or as blebs or laminae replacing pyroxene. Some Group 2 xenoliths have cumulate textures but near monomineralic amphibole xenoliths are coarse grained with bladed or comb textures. Pyroxene in Group 3 xenoliths has a polygonal granoblastic texture that is commonly overprinted by veining and amphibole replacement. Group 1 and most Group 2 xenoliths have major, trace element and Sr, Nd and Pb isotope compositions indicating affinity with the host volcanic rocks. Geochemical variation can be modelled by assimilation fractional crystallisation (AFC) and fractional crystallisation (FC) of basaltic parents assuming an assimilant with the composition of average crystalline basement and Group 1 xenoliths have

  13. The 2003 eruption of Anatahan volcano, Commonwealth of the Northern Mariana Islands: Chronology, volcanology, and deformation

    USGS Publications Warehouse

    Trusdell, F.A.; Moore, R.B.; Sako, M.; White, R.A.; Koyanagi, S.K.; Chong, R.; Camacho, J.T.

    2005-01-01

    The first historical eruption on Anatahan Island occurred on 10 May 2003 from the east crater of the volcano. The eruption was preceded by several hours of seismicity. Two and a half hours before the outbreak, the number of earthquakes surged to more than 100 events per hour. At 0730 UTC, the Washington Volcanic Ash Advisory Center issued an ash advisory. Although the eruption lasted for 3 months, the majority of erupted material was expelled during the first 2 weeks. The opening episode of the eruption resulted in a deposit of juvenile scoria and lithic clasts, the latter derived from geothermally altered colluvial fill from the vent area. The opening episode was followed by crater enlargement and deepening, which produced deposits of coarse, reddish-brown ash containing a mixture of juvenile and lithic clasts. The third episode of the eruption produced coarse ash and lapilli comprised of juvenile scoria and minor amounts of lithics. Plume heights were 4500 to 13,000 m for the initial three phases. The fourth episode, from about May 18 through early August, was characterized by smaller plume heights of 900 to 2400 m, and steam was the dominant component. Minor amounts of coarse ash and accretionary-lapilli ash comprise most of the deposits of the fourth episode, although ballistic blocks and bombs of andesite lava are also locally present. These andesite blocks were emplaced by an explosion on 14 June, which destroyed a small lava dome extruded during the first week of June. Activity waned as the summer progressed, and subsequent ash deposits accumulated in July and early August, by which time the eruption had effectively ended. In September and October, degassing and geothermal activity continued, characterized by small geysers, boiling water, and jetting steam. Noteworthy deviations from this activity were a surge event in late May-early June and the destruction of the lava dome on 14 June. We calculated on-land tephra-fall deposits to have a bulk volume of

  14. Hydrothermal mineralization at Kick'em Jenny submarine volcano in the Lesser Antilles island arc

    NASA Astrophysics Data System (ADS)

    Olsen, R.; Carey, S.; Sigurdsson, H.; Cornell, W. C.

    2011-12-01

    Kick 'em Jenny (KeJ) is an active submarine volcano located in the Lesser Antilles island arc, ~7.5 km northwest of Grenada. Of the twelve eruptions detected since 1939, most have been explosive as evidenced by eyewitness accounts in 1939, 1974, and 1988 and the dominance of explosive eruption products recovered by dredging. In 2003, vigorous hydrothermal activity was observed in the crater of KeJ. Video footage taken by a remotely operated vehicle (ROV) during the cruise RB-03-03 of the R/V Ronald Brown documented the venting of a vapor phase in the form of bubbles that ascended through the water column and a clear fluid phase in the form of shimmering water. The shimmering water generally ascended through the water column but can also been seen flowing down gradient from a fissure at the top of a fine-grained sediment mound. These fine-grained sediment mounds are the only structure associated with hydrothermal venting; spire or chimney structures were not observed. Hydrothermal venting was also observed coming from patches of coarse-grained volcaniclastic sediment on the crater floor and from talus slopes around the perimeter of the crater. Samples were collected from these areas and from areas void of hydrothermal activity. XRD and ICPMS analyses of bulk sediment were carried out to investigate the geochemical relationships between sediment types. Sediment samples from the hydrothermal mound structures are comprised of the same components (plagioclase, amphibole, pyroxene, and scoria) as sediment samples from areas void of hydrothermal activity (primary volcaniclastic sediment) in the 500-63 μm size range. High resolution grain size analyses show that >78% of sediment in the hydrothermal mound samples are between 63-2 μm with 6-20% clay sized (<2 μm) whereas <40% of the primary volcaniclastic sediment is between 63-2 μm with ~2% clay sized. The presence of clay minerals (smectite, illite, talc, and I/S mixed layer) in the hydrothermal mound samples was

  15. The 2003 eruption of Anatahan volcano, Commonwealth of the Northern Mariana Islands: Chronology, volcanology, and deformation

    NASA Astrophysics Data System (ADS)

    Trusdell, Frank A.; Moore, Richard B.; Sako, Maurice; White, Randall A.; Koyanagi, Stuart K.; Chong, Ramon; Camacho, Juan T.

    2005-08-01

    The first historical eruption on Anatahan Island occurred on 10 May 2003 from the east crater of the volcano. The eruption was preceded by several hours of seismicity. Two and a half hours before the outbreak, the number of earthquakes surged to more than 100 events per hour. At 0730 UTC, the Washington Volcanic Ash Advisory Center issued an ash advisory. Although the eruption lasted for 3 months, the majority of erupted material was expelled during the first 2 weeks. The opening episode of the eruption resulted in a deposit of juvenile scoria and lithic clasts, the latter derived from geothermally altered colluvial fill from the vent area. The opening episode was followed by crater enlargement and deepening, which produced deposits of coarse, reddish-brown ash containing a mixture of juvenile and lithic clasts. The third episode of the eruption produced coarse ash and lapilli comprised of juvenile scoria and minor amounts of lithics. Plume heights were 4500 to 13,000 m for the initial three phases. The fourth episode, from about May 18 through early August, was characterized by smaller plume heights of 900 to 2400 m, and steam was the dominant component. Minor amounts of coarse ash and accretionary-lapilli ash comprise most of the deposits of the fourth episode, although ballistic blocks and bombs of andesite lava are also locally present. These andesite blocks were emplaced by an explosion on 14 June, which destroyed a small lava dome extruded during the first week of June. Activity waned as the summer progressed, and subsequent ash deposits accumulated in July and early August, by which time the eruption had effectively ended. In September and October, degassing and geothermal activity continued, characterized by small geysers, boiling water, and jetting steam. Noteworthy deviations from this activity were a surge event in late May-early June and the destruction of the lava dome on 14 June. We calculated on-land tephra-fall deposits to have a bulk volume of

  16. Volcano-ice-sea interaction in the Cerro Santa Marta area, northwest James Ross Island, Antarctic Peninsula

    NASA Astrophysics Data System (ADS)

    Calabozo, Fernando M.; Strelin, Jorge A.; Orihashi, Yuji; Sumino, Hirochika; Keller, Randall A.

    2015-05-01

    We present here the results of detailed mapping, lithofacies analysis and stratigraphy of the Neogene James Ross Island Volcanic Group (Antarctic Peninsula) in the Cerro Santa Marta area (northwest of James Ross Island), in order to give constraints on the evolution of a glaciated volcanic island. Our field results included recognition and interpretation of seventeen volcanic and glacial lithofacies, together with their vertical and lateral arrangements, supported by four new unspiked K-Ar ages. This allowed us to conclude that the construction of the volcanic pile in this area took place during two main eruptive stages (Eruptive Stages 1 and 2), separated from the Cretaceous bedrock and from each other by two major glacial unconformities (U1 and U2). The U1 unconformity is related to Antarctic Peninsula Ice sheet expansion during the late Miocene (before 6.2 Ma) and deposition of glacial lithofacies in a glaciomarine setting. Following this glacial advance, Eruptive Stage 1 (6.2-4.6 Ma) volcanism started with subaerial extrusion of lava flows from an unrecognized vent north of the study area, with eruptions later fed from vent/s centered at Cerro Santa Marta volcano, where cinder cone deposits and a volcanic conduit/lava lake are preserved. These lava flows fed an extensive (> 7 km long) hyaloclastite delta system that was probably emplaced in a shallow marine environment. A second unconformity (U2) was related to expansion of a local ice cap, centered on James Ross Island, which truncated all the eruptive units of Eruptive Stage 1. Concomitant with glacier advance, renewed volcanic activity (Eruptive Stage 2) started after 4.6 Ma and volcanic products were fed again by Cerro Santa Marta vents. We infer that glaciovolcanic eruptions occurred under a moderately thin (~ 300 m) glacier, in good agreement with previous estimates of paleo-ice thickness for the James Ross Island area during the Pliocene.

  17. Use of precipitation and groundwater isotopes to interpret regional hydrology on a tropical volcanic island: Kilauea volcano area, Hawaii

    USGS Publications Warehouse

    Scholl, M.A.; Ingebritsen, S.E.; Janik, C.J.; Kauahikaua, J.P.

    1996-01-01

    Isotope tracer methods were used to determine flow paths, recharge areas, and relative age for groundwater in the Kilauea volcano area of the Island of Hawaii. A network of up to 66 precipitation collectors was emplaced in the study area and sampled twice yearly for a 3-year period. Stable isotopes in rainfall show three distinct isotopic gradients with elevation, which are correlated with trade wind, rain shadow, and high- elevation climatological patterns. Temporal variations in precipitation isotopes are controlled more by the frequency of storms than by seasonal temperature fluctuations. Results from this study suggest that (1) sampling network design must take into account areal variations in rainfall patterns on islands and in continental coastal areas and (2) isotope/elevation gradients on other tropical islands may be predictable on the basis of similar climatology. Groundwater was sampled yearly in coastal springs, wells, and a few high-elevation springs. Areal contrasts in groundwater stable isotopes and tritium indicate that the volcanic rift zones compartmentalize the regional groundwater system, isolating the groundwater south of Kilauea's summit and rift zones. Part of the Southwest Rift gone appears to act as a conduit for water from higher elevation, but there is no evidence for downrift flow in the springs and shallow wells sampled in the lower East Rift Zone.

  18. Real-time infrasonic monitoring of the eruption at a remote island volcano using seismoacoustic cross correlation

    NASA Astrophysics Data System (ADS)

    Nishida, Kiwamu; Ichihara, Mie

    2016-02-01

    On 2013 November 20, a submarine eruption started close to Nishinoshima island, which lies ˜1000 km south of Tokyo. Real-time monitoring of the eruption is crucial for understanding the formation processes of the new volcano island and related disaster prevention. In situ monitoring, however, is difficult in practice because the closest inhabited island, Chichijima, is 130 km away from Nishinoshima. This study presents an infrasonic monitoring method that uses cross-correlating records at a pair of online stations on Chichijima. One is the horizontal ground velocity recorded at a permanent seismic station operated by the Japan Meteorological Agency (JMA). The seismic records were corrected for atmospheric pressure using an empirical ground response to infrasound. The other is the air pressure recorded at the JMA Meteorological Observatory. For each station, we divided the whole records into 3600-s segments. To suppress outliers, each segment was normalized by the envelope function. We then calculated cross-correlation functions between the pair of stations using the fast Fourier transform. They present clear successive arrivals of infrasound coming from Nishinoshima. We also conducted an offline tripartite-array observation using three low-frequency microphones with a station spacing of ˜50 m installed in 2013 May. The array analysis supports the results obtained from the online stations. The typical root-mean-squared amplitude is on the order of 0.01 Pa, and the typical duration is several days. The amplitudes were primarily controlled by the effective sound velocity structure from Nishinoshima to Chichijima. The infrasonic observations together with the meteorological observation at Chichijima suggest that infrasonic activity was not present in the first two weeks in 2015 January. With the help of a more quantitative estimation of the meteorological effect, we could infer eruptive activity in real time. Now many online seismic stations are available worldwide

  19. Chronology of the seismic and ground deformation precursors of the 2014 Fogo Volcano - Cape Verde Islands - eruption.

    NASA Astrophysics Data System (ADS)

    Day, S. J.; Faria, B. V. E.

    2015-12-01

    The most recent eruption of Fogo Volcano, Cape Verde Islands started on the 23 November 2014 at 10h15 (CVT), after 19 years of quiescence. Several months before the begging of the eruption, the seismic activity started to deviate from the baseline, with the appearance of a class of events that was not recorded before then. This activity was characterized by a significant number of instrumentally detected, very low magnitude seismic events, sometimes more than 100 per day. In September those events became more energetic and analysis indicated that they could be of volcano-tectonic (VT) origin. The first VT event to be located was on 4 October with a 2.5 local magnitude: it was located slightly to the south of the middle of the island at between 15.5 and 16 km depth. This was deeper than normal for background VT events and coincided with the depth of last magma equilibration in the 1995 eruption. It was therefore interpreted as a possible precursor of an eruption: thus the alert level was raised to level 2, and the civil protection authorities were informed. On the following weeks the rate of VT events slightly increased and the focal depths became shallower. Very sporadic harmonic volcano tremor episodes and very few and weak long-period events were also recorded. From about the 15 to 21 November, the VT activity rate oscillated, and hypocentres tended to gather in the vicinity of an inferred dike emplacement and at shallower depth - 6 to 5 km b.s.l. On the first hours of the 22 November seismic rate increased from 3 to 6 events per hour and the events became more energetic. After 19h30 (CVT), when the magma reached the ductile-brittle transition zone (5 to 4 km b.s.l), the seismic rate increased again to more than one event per minute; earthquake magnitudes increased as well. At about 03h00 (CVT) the tilt records shown a prominent ground deformation. Continuous volcanic tremor started only one to half an hour before the start of the eruption.

  20. Significant discharge of CO2 from hydrothermalism associated with the submarine volcano of El Hierro Island.

    PubMed

    Santana-Casiano, J M; Fraile-Nuez, E; González-Dávila, M; Baker, E T; Resing, J A; Walker, S L

    2016-01-01

    The residual hydrothermalism associated with submarine volcanoes, following an eruption event, plays an important role in the supply of CO2 to the ocean. The emitted CO2 increases the acidity of seawater. The submarine volcano of El Hierro, in its degasification stage, provided an excellent opportunity to study the effect of volcanic CO2 on the seawater carbonate system, the global carbon flux, and local ocean acidification. A detailed survey of the volcanic edifice was carried out using seven CTD-pH-ORP tow-yo studies, localizing the redox and acidic changes, which were used to obtain surface maps of anomalies. In order to investigate the temporal variability of the system, two CTD-pH-ORP yo-yo studies were conducted that included discrete sampling for carbonate system parameters. Meridional tow-yos were used to calculate the amount of volcanic CO2 added to the water column for each surveyed section. The inputs of CO2 along multiple sections combined with measurements of oceanic currents produced an estimated volcanic CO2 flux = 6.0 10(5) ± 1.1 10(5 )kg d(-1) which is ~0.1% of global volcanic CO2 flux. Finally, the CO2 emitted by El Hierro increases the acidity above the volcano by ~20%.

  1. Significant discharge of CO2 from hydrothermalism associated with the submarine volcano of El Hierro Island

    NASA Astrophysics Data System (ADS)

    Santana-Casiano, J. M.; Fraile-Nuez, E.; González-Dávila, M.; Baker, E. T.; Resing, J. A.; Walker, S. L.

    2016-05-01

    The residual hydrothermalism associated with submarine volcanoes, following an eruption event, plays an important role in the supply of CO2 to the ocean. The emitted CO2 increases the acidity of seawater. The submarine volcano of El Hierro, in its degasification stage, provided an excellent opportunity to study the effect of volcanic CO2 on the seawater carbonate system, the global carbon flux, and local ocean acidification. A detailed survey of the volcanic edifice was carried out using seven CTD-pH-ORP tow-yo studies, localizing the redox and acidic changes, which were used to obtain surface maps of anomalies. In order to investigate the temporal variability of the system, two CTD-pH-ORP yo-yo studies were conducted that included discrete sampling for carbonate system parameters. Meridional tow-yos were used to calculate the amount of volcanic CO2 added to the water column for each surveyed section. The inputs of CO2 along multiple sections combined with measurements of oceanic currents produced an estimated volcanic CO2 flux = 6.0 105 ± 1.1 105 kg d‑1 which is ~0.1% of global volcanic CO2 flux. Finally, the CO2 emitted by El Hierro increases the acidity above the volcano by ~20%.

  2. Beryllium geochemistry constraints on the hydraulic behavior of mud volcanoes: the Trinidad Island case

    NASA Astrophysics Data System (ADS)

    Castrec-Rouelle, M.; Bourlès, D. L.; Boulègue, J.; Dia, A. N.

    2002-11-01

    To constrain Trinidad mud volcanoes hydraulic behavior, both cosmogenic 10Be ( t1/2=1.5 Myr) and 9Be concentrations have been measured in fluid and associated expelled mud. As previously evidenced [A.N. Dia, M. Castrec, J. Boulègue, P. Comeau, Trinidad Mud Volcanoes: where do the expelled fluids come from? Geochim. Cosmochim. Acta 63 (1999) 1023-1038] from δ 18O values and Cl concentrations, 9Be concentrations in the fluids mostly reflect the mixing of two deep components: REM I and REM II. REM I (δ 18O=10.5‰, Cl≈275 mM and 9Be≈0.05 nM) has characteristics of a continental fluid while REM II (δ 18O=3‰, Cl≈350 mM and 9Be≈1 nM) results from seawater-volcanogenic derived sediment interaction. Although 10Be concentrations in the fluid samples are close to the detection limit, the distribution of both beryllium isotopes between the hydroxylamine leachable and residual phases indicates exchange reaction with fluid younger than 15 Myr. Comparison between the lowest REM I 10Be/ 9Be ratio in fluid recorded by the hydroxylamine leachable phase (TD5 mud sample) and the 10Be/ 9Be ratio representative of meteoric contribution in the recharge area (TD8 fluid sample) yields a circulation rate of REM I fluid in the Trinidad mud volcanoes of several 10 -1 m/yr.

  3. Significant discharge of CO2 from hydrothermalism associated with the submarine volcano of El Hierro Island.

    PubMed

    Santana-Casiano, J M; Fraile-Nuez, E; González-Dávila, M; Baker, E T; Resing, J A; Walker, S L

    2016-01-01

    The residual hydrothermalism associated with submarine volcanoes, following an eruption event, plays an important role in the supply of CO2 to the ocean. The emitted CO2 increases the acidity of seawater. The submarine volcano of El Hierro, in its degasification stage, provided an excellent opportunity to study the effect of volcanic CO2 on the seawater carbonate system, the global carbon flux, and local ocean acidification. A detailed survey of the volcanic edifice was carried out using seven CTD-pH-ORP tow-yo studies, localizing the redox and acidic changes, which were used to obtain surface maps of anomalies. In order to investigate the temporal variability of the system, two CTD-pH-ORP yo-yo studies were conducted that included discrete sampling for carbonate system parameters. Meridional tow-yos were used to calculate the amount of volcanic CO2 added to the water column for each surveyed section. The inputs of CO2 along multiple sections combined with measurements of oceanic currents produced an estimated volcanic CO2 flux = 6.0 10(5) ± 1.1 10(5 )kg d(-1) which is ~0.1% of global volcanic CO2 flux. Finally, the CO2 emitted by El Hierro increases the acidity above the volcano by ~20%. PMID:27157062

  4. Significant discharge of CO2 from hydrothermalism associated with the submarine volcano of El Hierro Island

    PubMed Central

    Santana-Casiano, J. M.; Fraile-Nuez, E.; González-Dávila, M.; Baker, E. T.; Resing, J. A.; Walker, S. L.

    2016-01-01

    The residual hydrothermalism associated with submarine volcanoes, following an eruption event, plays an important role in the supply of CO2 to the ocean. The emitted CO2 increases the acidity of seawater. The submarine volcano of El Hierro, in its degasification stage, provided an excellent opportunity to study the effect of volcanic CO2 on the seawater carbonate system, the global carbon flux, and local ocean acidification. A detailed survey of the volcanic edifice was carried out using seven CTD-pH-ORP tow-yo studies, localizing the redox and acidic changes, which were used to obtain surface maps of anomalies. In order to investigate the temporal variability of the system, two CTD-pH-ORP yo-yo studies were conducted that included discrete sampling for carbonate system parameters. Meridional tow-yos were used to calculate the amount of volcanic CO2 added to the water column for each surveyed section. The inputs of CO2 along multiple sections combined with measurements of oceanic currents produced an estimated volcanic CO2 flux = 6.0 105 ± 1.1 105 kg d−1 which is ~0.1% of global volcanic CO2 flux. Finally, the CO2 emitted by El Hierro increases the acidity above the volcano by ~20%. PMID:27157062

  5. Composition, geometry, and emplacement dynamics of a large volcanic island landslide offshore Martinique: From volcano flank-collapse to seafloor sediment failure?

    NASA Astrophysics Data System (ADS)

    Brunet, Morgane; Le Friant, Anne; Boudon, Georges; Lafuerza, Sara; Talling, Peter; Hornbach, Matthew; Ishizuka, Osamu; Lebas, Elodie; Guyard, Hervé

    2016-03-01

    Landslides are common features in the vicinity of volcanic islands. In this contribution, we investigate landslides emplacement and dynamics around the volcanic island of Martinique based on the first scientific drilling of such deposits. The evolution of the active Montagne Pelée volcano on this island has been marked by three major flank-collapses that removed much of the western flank of the volcano. Subaerial collapse volumes vary from 2 to 25 km3 and debris avalanches flowed into the Grenada Basin. High-resolution seismic data (AGUADOMAR-1999, CARAVAL-2002, and GWADASEIS-2009) is combined with new drill cores that penetrate up to 430 m through the three submarine landslide deposits previously associated to the aerial flank-collapses (Site U1399, Site U1400, Site U1401, IODP Expedition 340, Joides Resolution, March-April 2012). This combined geophysical and core data provide an improved understanding of landslide processes offshore a volcanic island. The integrated analysis shows a large submarine landslide deposit, without debris avalanche deposits coming from the volcano, comprising up to 300 km3 of remobilized seafloor sediment that extends for 70 km away from the coast and covers an area of 2100 km2. Our new data suggest that the aerial debris avalanche deposit enter the sea but stop at the base of submarine flank. We propose a new model dealing with seafloor sediment failures and landslide propagation mechanisms, triggered by volcanic flank-collapse events affecting Montagne Pelée volcano. Newly recognized landslide deposits occur deeper in the stratigraphy, suggesting the recurrence of large-scale mass-wasting processes offshore the island and thus, the necessity to better assess the associated tsunami hazards in the region.

  6. Characterization of pyroclastic deposits and pre-eruptive soils following the 2008 eruption of Kasatochi Island Volcano, Alaska

    USGS Publications Warehouse

    Wang, B.; Michaelson, G.; Ping, C.-L.; Plumlee, G.; Hageman, P.

    2010-01-01

    The 78 August 2008 eruption of Kasatochi Island volcano blanketed the island in newly generated pyroclastic deposits and deposited ash into the ocean and onto nearby islands. Concentrations of water soluble Fe, Cu, and Zn determined from a 1:20 deionized water leachate of the ash were sufficient to provide short-term fertilization of the surface ocean. The 2008 pyroclastic deposits were thicker in concavities at bases of steeper slopes and thinner on steep slopes and ridge crests. By summer 2009, secondary erosion had exposed the pre-eruption soils along gulley walls and in gully bottoms on the southern and eastern slopes, respectively. Topographic and microtopographic position altered the depositional patterns of the pyroclastic flows and resulted in pre-eruption soils being buried by as little as 1 m of ash. The different erosion patterns gave rise to three surfaces on which future ecosystems will likely develop: largely pre-eruptive soils; fresh pyroclastic deposits influenced by shallowly buried, pre-eruptive soil; and thick (>1 m) pyroclastic deposits. As expected, the chemical composition differed between the pyroclastic deposits and the pre-eruptive soils. Pre-eruptive soils hold stocks of C and N important for establishing biota that are lacking in the fresh pyroclastic deposits. The pyroclastic deposits are a source for P and K but have negligible nutrient holding capacity, making these elements vulnerable to leaching loss. Consequently, the pre-eruption soils may also represent an important long-term P and K source. ?? 2010 Regents of the University of Colorado.

  7. Petrologic observations and multiphase dynamics in highly-crystalline magmatic mushes sourcing Galápagos Island volcanoes

    NASA Astrophysics Data System (ADS)

    Schleicher, J.; Bergantz, G. W.; Geist, D.

    2013-12-01

    The inability to directly observe magma chambers makes it difficult to understand their dynamics. Yet conditions within the chamber determines whether an eruption will occur, or if the magma is allowed to cool to complete crystallization. Eruption styles are also conditioned by these dynamics, as the amount of overpressure within the chamber regulates effusive or explosive eruptions. Plutons and volcanoes appear to share similar states: magma reservoirs that are temporally and spatially dominated by crystal-rich states, known as magmatic mushes. To explore the dynamics of mushes, we turn to the relatively simple ocean island end-member of magmatic systems. Ocean island porphyritic basalt flows provide a snapshot of the mush conditions prior to eruption. The Galápagos Islands are a system of ocean islands displaying spatial and temporal variation in their eruption styles and deposits. We have collected porphyritic basalt samples from Rábida Island of the Galápagos Archipelago which contains deposits ranging in ages from 0.7-1.0 Ma. Chemical zoning within phenocrysts indicates intermittent efficient mixing occurs within the mush, despite high viscosities and corresponding low-Reynolds number conditions. To further explore the dynamics of mixing, we present preliminary Eulerian-Lagrangian multiphase models using the fluids modeling software MFIX (Multiphase Flow with Interphase eXchanges). This computational fluid dynamics-discrete element method (CFD-DEM) allows for individual crystal tracking within the system and monitors interactions between the fluid and solid phases. Of special interest is the open-system dynamical response of a mush to a reintrusion event. Unlike high-Reynolds number flows, such as air or water systems, magmatic mushes have high viscosities, indicating that turbulent motion is not the primary mixing mechanism. Instead, mixing appears to be caused by mechanical unlocking from an increase in pore pressure as additional magma is injected. The

  8. Assessment of the exposure of islanders to ash from the Soufriere Hills volcano, Montserrat, British West Indies

    PubMed Central

    Searl, A; Nicholl, A; Baxter, P

    2002-01-01

    Background and Aims: The Soufriere Hills volcano, Montserrat, has been erupting since July 1995 and volcanic ash has fallen on the island throughout most of the eruption. The ash contains substantial quantities of respirable particles and unusually large amounts (15–20%) of the crystalline silica mineral, cristobalite. The purpose of the surveys described here, undertaken between December 1996 and April 2000, was to determine levels of personal exposure of islanders to volcanic ash and cristobalite in order to inform advice on the associated risks to health and the measures required to reduce exposure. Methods: Surveys of personal exposure to respirable dust and cristobalite were undertaken using cyclone samplers. In addition, direct reading instruments (DUSTTRAK) were used to monitor ambient air concentrations of PM10 at fixed sites and also to provide information about exposures to airborne particles associated with selected activities. Results: Environmental concentrations of airborne ash have been greatest in the areas where the most ash has been deposited and during dry weather. Individual exposure to airborne ash was related to occupation, with the highest exposures among gardeners, cleaners, roadworkers, and police at roadside checkpoints. During 1997 many of these individuals were exposed to concentrations of cristobalite that exceeded the ACGIH recommended occupational exposure limit. Since the population became confined to the north of the island in October 1997, even those in relatively dusty occupations have received exposures to cristobalite well below this limit. Conclusions: Most of the 4500 people who have remained on island since the eruption began have not been exposed to sufficiently high concentrations of airborne dust for long enough to be at risk of developing silicosis. However, more than a dozen individuals continued to experience frequent high occupational exposures to volcanic ash, some of whom may have had sufficient exposure to

  9. IESID: Automatic system for monitoring ground deformation on the Deception Island volcano (Antarctica)

    NASA Astrophysics Data System (ADS)

    Peci, Luis Miguel; Berrocoso, Manuel; Páez, Raúl; Fernández-Ros, Alberto; de Gil, Amós

    2012-11-01

    When establishing the relative distance between two GNSS-GPS stations with sub-centimeter accuracy, it is necessary to have auxiliary data, some of which can only be collected some time after the moment of measurement. However, for monitoring highly-active geodynamic areas, such as volcanoes and landslides, data precision is not as essential as rapid availability, processing of data in real-time, and fast interpretation of the results. This paper describes the development of an integrated automatic system for monitoring volcanic deformation in quasi real-time, applied to the Deception volcano (Antarctica). This experimental system integrates two independent modules that enable researchers to monitor and control the status of the GNSS-GPS stations, and to determine a surface deformation parameter. It comprises three permanent stations, one of which serves as the reference for assessing the relative distance in relation to the other two. The availability of GNSS-GPS data in quasi real-time is achieved by means of a WiFi infrastructure and automated data processing. This system provides, in quasi real-time, a time series of varying distances that tells us the extent to which any ground deformation is taking place.

  10. The submarine volcano eruption off El Hierro Island: effects on the scattering migrant biota and the evolution of the pelagic communities.

    PubMed

    Ariza, Alejandro; Kaartvedt, Stein; Røstad, Anders; Garijo, Juan Carlos; Arístegui, Javier; Fraile-Nuez, Eugenio; Hernández-León, Santiago

    2014-01-01

    The submarine volcano eruption off El Hierro Island (Canary Islands) on 10 October 2011 promoted dramatic perturbation of the water column leading to changes in the distribution of pelagic fauna. To study the response of the scattering biota, we combined acoustic data with hydrographic profiles and concurrent sea surface turbidity indexes from satellite imagery. We also monitored changes in the plankton and nekton communities through the eruptive and post-eruptive phases. Decrease of oxygen, acidification, rising temperature and deposition of chemicals in shallow waters resulted in a reduction of epipelagic stocks and a disruption of diel vertical migration (nocturnal ascent) of mesopelagic organisms. Furthermore, decreased light levels at depth caused by extinction in the volcanic plume resulted in a significant shallowing of the deep acoustic scattering layer. Once the eruption ceased, the distribution and abundances of the pelagic biota returned to baseline levels. There was no evidence of a volcano-induced bloom in the plankton community. PMID:25047077

  11. The submarine volcano eruption off El Hierro Island: effects on the scattering migrant biota and the evolution of the pelagic communities.

    PubMed

    Ariza, Alejandro; Kaartvedt, Stein; Røstad, Anders; Garijo, Juan Carlos; Arístegui, Javier; Fraile-Nuez, Eugenio; Hernández-León, Santiago

    2014-01-01

    The submarine volcano eruption off El Hierro Island (Canary Islands) on 10 October 2011 promoted dramatic perturbation of the water column leading to changes in the distribution of pelagic fauna. To study the response of the scattering biota, we combined acoustic data with hydrographic profiles and concurrent sea surface turbidity indexes from satellite imagery. We also monitored changes in the plankton and nekton communities through the eruptive and post-eruptive phases. Decrease of oxygen, acidification, rising temperature and deposition of chemicals in shallow waters resulted in a reduction of epipelagic stocks and a disruption of diel vertical migration (nocturnal ascent) of mesopelagic organisms. Furthermore, decreased light levels at depth caused by extinction in the volcanic plume resulted in a significant shallowing of the deep acoustic scattering layer. Once the eruption ceased, the distribution and abundances of the pelagic biota returned to baseline levels. There was no evidence of a volcano-induced bloom in the plankton community.

  12. The Submarine Volcano Eruption off El Hierro Island: Effects on the Scattering Migrant Biota and the Evolution of the Pelagic Communities

    PubMed Central

    Ariza, Alejandro; Kaartvedt, Stein; Røstad, Anders; Garijo, Juan Carlos; Arístegui, Javier; Fraile-Nuez, Eugenio; Hernández-León, Santiago

    2014-01-01

    The submarine volcano eruption off El Hierro Island (Canary Islands) on 10 October 2011 promoted dramatic perturbation of the water column leading to changes in the distribution of pelagic fauna. To study the response of the scattering biota, we combined acoustic data with hydrographic profiles and concurrent sea surface turbidity indexes from satellite imagery. We also monitored changes in the plankton and nekton communities through the eruptive and post-eruptive phases. Decrease of oxygen, acidification, rising temperature and deposition of chemicals in shallow waters resulted in a reduction of epipelagic stocks and a disruption of diel vertical migration (nocturnal ascent) of mesopelagic organisms. Furthermore, decreased light levels at depth caused by extinction in the volcanic plume resulted in a significant shallowing of the deep acoustic scattering layer. Once the eruption ceased, the distribution and abundances of the pelagic biota returned to baseline levels. There was no evidence of a volcano-induced bloom in the plankton community. PMID:25047077

  13. Ground deformation of Tenerife volcano island revealed by 1992-2005 DInSAR time series:

    NASA Astrophysics Data System (ADS)

    Tizzani, P.

    2009-04-01

    We study the state of deformation of Tenerife Island using Differential Synthetic Aperture Radar Interferometry (DInSAR). We apply the Small BAseline Subset (SBAS) DInSAR algorithm to radar images acquired from 1992 to 2005 by ERS sensors to determine the deformation rate distribution and the time series for the coherent pixels identified in the island. Our analysis reveals that the summit area of the volcanic edifice is characterized by a continuous subsidence extending well beyond Las Cañadas caldera rim and corresponding to the intrusive core of the island. These results, coupled with GPS ones, structural and geological information and deformation modelling, suggest that the intrusive complex is subsiding into a weak lithosphere and that the volcanic edifice is in a state of compression. We also detect more localized deformation patterns correlated with water table changes and variations in the time deformation associated with the seismic crisis in 2004.

  14. Towards a Proactive Risk Mitigation Strategy at La Fossa Volcano, Vulcano Island

    NASA Astrophysics Data System (ADS)

    Biass, S.; Gregg, C. E.; Frischknecht, C.; Falcone, J. L.; Lestuzzi, P.; di Traglia, F.; Rosi, M.; Bonadonna, C.

    2014-12-01

    A comprehensive risk assessment framework was built to develop proactive risk reduction measures for Vulcano Island, Italy. This framework includes identification of eruption scenarios; probabilistic hazard assessment, quantification of hazard impacts on the built environment, accessibility assessment on the island and risk perception study. Vulcano, a 21 km2 island with two primary communities host to 900 permanent residents and up to 10,000 visitors during summer, shows a strong dependency on the mainland for basic needs (water, energy) and relies on a ~2 month tourism season for its economy. The recent stratigraphy reveals a dominance of vulcanian and subplinian eruptions, producing a range of hazards acting at different time scales. We developed new methods to probabilistically quantify the hazard related to ballistics, lahars and tephra for all eruption styles. We also elaborated field- and GIS- based methods to assess the physical vulnerability of the built environment and created dynamic models of accessibility. Results outline the difference of hazard between short and long-lasting eruptions. A subplinian eruption has a 50% probability of impacting ~30% of the buildings within days after the eruption, but the year-long damage resulting from a long-lasting vulcanian eruption is similar if tephra is not removed from rooftops. Similarly, a subplinian eruption results in a volume of 7x105 m3 of material potentially remobilized into lahars soon after the eruption. Similar volumes are expected for a vulcanian activity over years, increasing the hazard of small lahars. Preferential lahar paths affect critical infrastructures lacking redundancy, such as the road network, communications systems, the island's only gas station, and access to the island's two evacuation ports. Such results from hazard, physical and systemic vulnerability help establish proactive volcanic risk mitigation strategies and may be applicable in other island settings.

  15. Gaseous transport and deposition of gold in magmatic fluid: evidence from the active Kudryavy volcano, Kurile Islands

    NASA Astrophysics Data System (ADS)

    Yudovskaya, Marina A.; Distler, Vadim V.; Chaplygin, Ilya V.; Mokhov, Andrew V.; Trubkin, Nikolai V.; Gorbacheva, Sonya A.

    2006-03-01

    The distribution of gold in high-temperature fumarole gases of the Kudryavy volcano (Kurile Islands) was measured for gas, gas condensate, natural fumarolic sublimates, and precipitates in silica tubes from vents with outlet temperatures ranging from 380 to 870°C. Gold abundance in condensates ranges from 0.3 to 2.4 ppb, which is significantly lower than the abundances of transition metals. Gold contents in zoned precipitates from silica tubes increase gradually with a decrease in temperature to a maximum of 8 ppm in the oxychloride zone at a temperature of approximately 300°C. Total Au content in moderate-temperature sulfide and oxychloride zones is mainly a result of Au inclusions in the abundant Fe-Cu and Zn sulfide minerals as determined by instrumental neutron activation analysis. Most Au occurs as a Cu-Au-Ag triple alloy. Single grains of native gold and binary Au-Ag alloys were also identified among sublimates, but aggregates and crystals of Cu-Au-Ag alloy were found in all fumarolic fields, both in silica tube precipitates and in natural fumarolic crusts. Although the Au triple alloy is homogeneous on the scale of microns and has a composition close to (Cu,Ni,Zn)3(Au,Ag)2, transmission electron microscopy (TEM) shows that these alloy solid solutions consist of monocrystal domains of Au-Ag, Au-Cu, and possibly Cu2O. Gold occurs in oxide assemblages due to the decomposition of its halogenide complexes under high-temperature conditions (650-870°C). In lower temperature zones (<650°C), Au behavior is related to sulfur compounds whose evolution is strongly controlled by redox state. Other minerals that formed from gas transport and precipitation at Kudryavy volcano include garnet, aegirine, diopside, magnetite, anhydrite, molybdenite, multivalent molybdenum oxides (molybdite, tugarinovite, and ilsemannite), powellite, scheelite, wolframite, Na-K chlorides, pyrrhotite, wurtzite, greenockite, pyrite, galena, cubanite, rare native metals (including Fe, Cr, Mo

  16. 3-D Anisotropic Ambient Noise Tomography of Piton De La Fournaise Volcano (La Réunion Island)

    NASA Astrophysics Data System (ADS)

    Mordret, A.; Rivet, D. N.; Landes, M.; Shapiro, N.

    2014-12-01

    We cross-correlate four years of seismic noise continuously recorded by the seismic monitoring network of the Piton de la Fournaise volcano (La Réunion Island). The network is composed of 40 stations 27 of which have 3-component sensors. We use Vertical-to-Vertical (ZZ) cross-correlation components from all stations and Radial-to-Radial (RR) and Transverse-to-Transverse (TT) cross-correlations computed from 3-component records. The group velocity dispersion curves for Rayleigh and Love waves are measured using a Frequency-Time Analysis. We average measurements from ZZ and RR components to finally obtain 577 Rayleigh-wave dispersion curves. 395 Love-wave dispersion curves are obtained from the TT cross-correlations. We then regionalize the group velocities measurements to construct 2D dispersion maps at a set of periods between 0.4 and 8 s. Finally, we construct a 3D shear-velocity model down to 3 km below the sea level by jointly inverting the Rayleigh and Love wave group velocity maps with a Neighborhood Algorithm and with taking into account the radial anisotropy. The distribution of 3-D Voigt averaged S-wave velocities shows three distinct high-velocity anomalies surrounded by a low-velocity ring. The most western high-velocity anomaly is located below the actual "Plaine des Sables" and could be attributed to an old intrusive body at the location of the former volcanic center before it migrated toward its present location. The second high-velocity body is located below the summit of the volcano and likely corresponds to the actual preferential dyke intrusion zone as highlighted by the seismicity. The third high-velocity anomaly is located below the "Grandes Pentes" and the "Grand Brûlé" areas and is thought to be an imprint of the solidified magma chamber of the ancient dismantled "Les Alizé" volcano. The distribution of the radial anisotropy shows two main anomalies: a positive anisotropy (Vsh>Vsv) above sea level highlighting the recent edifice of Piton de

  17. Volcanogenic fluorine in rainwater around active degassing volcanoes: Mt. Etna and Stromboli Island, Italy.

    PubMed

    Bellomo, S; D'Alessandro, W; Longo, M

    2003-01-01

    Many studies have assessed the strong influence of volcanic activity on the surrounding environment. This is particularly true for strong gas emitters such as Mt. Etna and Stromboli volcanoes. Among volcanic gases, fluorine compounds are potentially very harmful. Fluorine cycling through rainwater in the above volcanic areas was studied analysing more than 400 monthly bulk samples. Data indicate that only approximately 1% of fluorine emission through the plume is deposited on the two volcanic areas by meteoric precipitations. Although measured bulk rainwater fluorine fluxes are comparable to and sometimes higher than in heavily polluted areas, their influence on the surrounding vegetation is limited. Only annual crops, in fact, show some damage that could be an effect of fluorine deposition, indicating that long-living endemic plant species or varieties have developed some kind of resistance.

  18. Tilt recorded by a portable broadband seismograph: The 2003 eruption of Anatahan Volcano, Mariana Islands

    USGS Publications Warehouse

    Wiens, D.A.; Pozgay, S.H.; Shore, P.J.; Sauter, A.W.; White, R.A.

    2005-01-01

    The horizontal components of broadband seismographs are highly sensitive to tilt, suggesting that commonly deployed portable broadband seismic sensors may record important tilt information associated with volcanic eruptions. We report on a tilt episode that coincides with the first historical eruption of Anatahan volcano on May 10, 2003. The tilt was recorded by a Strekheisen STS-2 seismograph deployed in an underground insulated chamber 7 km west of the active vent. An ultra-long period signal with a dominant period of several hours was recorded on the E-W component beginning at 06:20 GMT on May 10, which coincides with the onset of continuous volcano-tectonic (VT) seismicity and is one hour prior to the eruption time estimated by the Volcanic Ash Advisory Center. The signal is much smaller on the N-S component and absent on the vertical component, suggesting it results from tilt that is approximately radial with respect to the active vent. An estimate of tilt as a function of time is recovered by deconvolving the record to acceleration and dividing by the acceleration of gravity. The record indicates an initial episode of tilt downward away from the volcanic center from 06:20-09:30 GMT, which we interpret as inflation of the shallow volcanic source. The tilt reverses, recording deflation, from 09:30 until 17:50, after which the tilt signal becomes insignificant. The inflation corresponds to a period of numerous VT events, whereas fewer events were recorded during the deflation episode, and the VT events subsequently resumed after the end of the deflationary tilt. The maximum tilt of 2 microradians can be used to estimate the volume of the source inflation (???2 million in m3), assuming a simple Mogi source model. These calculations are consistent with other estimates of source volume if reasonable source depths are assumed. Examination of broadband records of other eruptions may disclose further previously unrecognized tilt signals. Copyright 2005 by the American

  19. Long- and short-term temporal variations of the diffuse CO2 emission from Timanfaya volcano, Lanzarote, Canary Islands

    NASA Astrophysics Data System (ADS)

    Hernández, P. A.; Padilla, G.; Calvo, D.; Padrón, E.; Melian, G.; Dionis, S.; Nolasco, D.; Barrancos, J.; Rodríguez, F.; Pérez, N.

    2012-04-01

    Lanzarote Island is an emergent part of the East Canary Ridge and it is situated approximately 100 km from the NW coast of Morocco, covering an area of about 795km2. The largest historical eruption of the Canary Islands, Timanfaya, took place during 1730-36 in this island when long-term eruptions from a NE-SW-trending fissure formed the Montañas del Fuego. The last eruption at Lanzarote Island occurred during 1824, Tinguaton volcano, and produced a much smaller lava flow that reached the SW coast. At present, one of the most prominent phenomena at Timanfaya volcanic field is the high maintained superficial temperatures occurring in the area since the 1730 volcanic eruption. The maximum temperatures recorded in this zone are 605°C, taken in a slightly inclined well 13 m deep. Since fumarolic activity is absent at the surface environment of Lanzarote, to study the diffuse CO2 emission becomes an ideal geochemical tool for monitoring its volcanic activity. Soil CO2 efflux surveys were conducted throughout Timanfaya volcanic field and surrounding areas during the summer periods of 2006, 2007, 2008, 2009, fall period of 2010 and winter, spring and summer periods of 2011 to investigate long and short-term temporal variations of the diffuse CO2 emission from Timanfaya volcano. Soil CO2 efflux surveys were undertaken at Timanfaya volcanic field always under stable weather conditions to minimize effects of meteorological conditions on the CO2 at the soil atmosphere. Approximately 370-430 sampling sites were selected at the surface environment of Timanfaya to obtain an even distribution of the sampling points over the study area. The accumulation chamber method (Parkinson et al., 1981) was used to perform soil CO2 efflux measurements in-situ by means of a portable non dispersive infrared (NDIR) CO2 analyzer, which was interfaced to a hand size computer that runs data acquisition software. At each sampling site, soil temperature at 15 and 40cm depth was also measured by

  20. Magma chamber history related to the shield building stage of Piton des Neiges volcano, La Réunion Island

    NASA Astrophysics Data System (ADS)

    Berthod, Carole; Michon, Laurent; Famin, Vincent; Bascou, Jérôme; Bachelery, Patrick

    2016-04-01

    reconstruction, gravimetric data (Gailler & Lénat, 2012) and submarine sedimentation (Lebas, 2012). It would have been built prior to 2 Ma and subsequently experienced a large north-directed destabilization. The PdN volcano later reconstructed south of the initial magmatic centre. Chevallier, L., & Vatin-Perignon, N. (1982). Volcano-structural evolution of Piton des Neiges, Reunion Island, Indian Ocean. Bulletin of Volcanology, 45(4), 285-298. Gailler, L.-S., & Lénat, J.-F. (2012). Internal architecture of La Réunion (Indian Ocean) inferred from geophysical data. Journal of Volcanology and Geothermal Research, 221-222(C), 83-98. http://doi.org/10.1016/j.jvolgeores.2012.01.015 Lebas, E. (2012). Processus de démantèlement des édifices volcaniques au cours de leur évolution : Application à La Réunion et Montserrat et comparaison avec d'autres édifices. Unpublished PhD Thesis, 1-379. Upton, B. G. J., & Wadsworth, W. (1972). Peridotitic and gabbroic rocks associated with the shield-forming lavas of Réunion. Contributions to Mineralogy and Petrology, 35, 139-158.

  1. Volcano-tectonic implications of 3-D velocity structures derived from joint active and passive source tomography of the island of Hawaii

    USGS Publications Warehouse

    Park, J.; Morgan, J.K.; Zelt, C.A.; Okubo, P.G.

    2009-01-01

    We present a velocity model of the onshore and offshore regions around the southern part of the island of Hawaii, including southern Mauna Kea, southeastern Hualalai, and the active volcanoes of Mauna Loa, and Kilauea, and Loihi seamount. The velocity model was inverted from about 200,000 first-arrival traveltime picks of earthquakes and air gun shots recorded at the Hawaiian Volcano Observatory (HVO). Reconstructed volcanic structures of the island provide us with an improved understanding of the volcano-tectonic evolution of Hawaiian volcanoes and their interactions. The summits and upper rift zones of the active volcanoes are characterized by high-velocity materials, correlated with intrusive magma cumulates. These high-velocity materials often do not extend the full lengths of the rift zones, suggesting that rift zone intrusions may be spatially limited. Seismicity tends to be localized seaward of the most active intrusive bodies. Low-velocity materials beneath parts of the active rift zones of Kilauea and Mauna Loa suggest discontinuous rift zone intrusives, possibly due to the presence of a preexisting volcanic edifice, e.g., along Mauna Loa beneath Kilauea's southwest rift zone, or alternatively, removal of high-velocity materials by large-scale landsliding, e.g., along Mauna Loa's western flank. Both locations also show increased seismicity that may result from edifice interactions or reactivation of buried faults. New high-velocity regions are recognized and suggest the presence of buried, and in some cases, previously unknown rift zones, within the northwest flank of Mauna Loa, and the south flanks of Mauna Loa, Hualalai, and Mauna Kea. Copyright 2009 by the American Geophysical Union.

  2. Paleozoic subduction complex and Paleozoic-Mesozoic island-arc volcano-plutonic assemblages in the northern Sierra terrane

    USGS Publications Warehouse

    Hanson, Richard E.; Girty, Gary H.; Harwood, David S.; Schweickert, Richard A.

    2000-01-01

    This field trip provides an overview of the stratigraphic and structural evolution of the northern Sierra terrane, which forms a significant part of the wall rocks on the western side of the later Mesozoic Sierra Nevada batholith in California. The terrane consists of a pre-Late Devonian subduction complex (Shoo Fly Complex) overlain by submarine arc-related deposits that record the evolution of three separate island-arc systems in the Late Sevonian-Early Mississippian, Permian, and Late Triassic-Jurassic. The two Paleozoic are packages and the underlying Shoo Fly Complex have an important bearing on plate-tectonic processes affecting the convergent margin outboard of the Paleozoic Cordilleran miogeocline, although their original paleogeographic relations to North America are controversial. The third arc package represents an overlap assemblage that ties the terrane to North America by the Late Triassic and helps constrain the nature and timing of Mesozoic orogenesis. Several of the field-trip stops examine the record of pre-Late Devonian subduction contained in the Shoo Fly Complex, as well as the paleovolcanology of the overlying Devonian to Jurassic arc rocks. Excellent glaciated exposures provide the opportunity to study a cross section through a tilted Devonian volcano-plutonic association. Additional stops focus on plutonic rocks emplaced during the Middle Jurassic arc magmatism in the terrane, and during the main pulse of Cretaceous magmatism in the Sierra Nevada batholith to the east.

  3. Observations on basaltic lava streams in tubes from Kilauea Volcano, island of Hawai'i

    USGS Publications Warehouse

    Kauahikaua, J.; Cashman, K.V.; Mattox, T.N.; Christina, Heliker C.; Hon, K.A.; Mangan, M.T.; Thornber, C.R.

    1998-01-01

    From 1986 to 1997, the Pu'u 'O'o-Kupaianaha eruption of Kilauea produced a vast pahoehoe flow field fed by lava tubes that extended 10-12 km from vents on the volcano's east rift zone to the ocean. Within a kilometer of the vent, tubes were as much as 20 m high and 10-25 m wide. On steep slopes (4-10??) a little farther away from the vent, some tubes formed by roofing over of lava channels. Lava streams were typically 1-2 m deep flowing within a tube that here was typically 5 m high and 3 m wide. On the coastal plain (<1??), tubes within inflated sheet flows were completely filled, typically 1-2 m high, and several tens of meters wide. Tubes develop as a flow's crust grows on the top, bottom, and sides of the tubes, restricting the size of the fluid core. The tubes start out with nearly elliptical cross-sectional shapes, many times wider than high. Broad, flat sheet flows evolve into elongate tumuli with an axial crack as the flanks of the original flow were progressively buried by breakouts. Temperature measurements and the presence of stalactites in active tubes confirmed that the tube walls were above the solidus and subject to melting. Sometimes, the tubes began downcutting. Progressive downcutting was frequently observed through skylights; a rate of 10 cm/d was measured at one skylight for nearly 2 months.

  4. Observations on basaltic lava streams in tubes from Kilauea Volcano, island of Hawai'i

    NASA Astrophysics Data System (ADS)

    Kauahikaua, Jim; Cashman, Katharine V.; Mattox, Tari N.; Heliker, C. Christina; Hon, Ken A.; Mangan, Margaret T.; Thornber, Carl R.

    1998-11-01

    From 1986 to 1997, the Pu'u 'O'o-Kupaianaha eruption of Kilauea produced a vast pahoehoe flow field fed by lava tubes that extended 10-12 km from vents on the volcano's east rift zone to the ocean. Within a kilometer of the vent, tubes were as much as 20 m high and 10-25 m wide. On steep slopes (4-10°) a little farther away from the vent, some tubes formed by roofing over of lava channels. Lava streams were typically 1-2 m deep flowing within a tube that here was typically 5 m high and 3 m wide. On the coastal plain (<1°), tubes within inflated sheet flows were completely filled, typically 1-2 m high, and several tens of meters wide. Tubes develop as a flow's crust grows on the top, bottom, and sides of the tubes, restricting the size of the fluid core. The tubes start out with nearly elliptical cross-sectional shapes, many times wider than high. Broad, flat sheet flows evolve into elongate tumuli with an axial crack as the flanks of the original flow were progressively buried by breakouts. Temperature measurements and the presence of stalactites in active tubes confirmed that the tube walls were above the solidus and subject to melting. Sometimes, the tubes began downcutting. Progressive downcutting was frequently observed through skylights; a rate of 10 cm/d was measured at one skylight for nearly 2 months.

  5. Transient volcano deformation sources imaged with interferometric synthetic aperture radar: Application to Seguam Island, Alaska

    USGS Publications Warehouse

    Masterlark, Timothy; Lu, Zhong

    2004-01-01

    Thirty interferometric synthetic aperture radar (InSAR) images, spanning various intervals during 1992–2000, document coeruptive and posteruptive deformation of the 1992–1993 eruption on Seguam Island, Alaska. A procedure that combines standard damped least squares inverse methods and collective surfaces, identifies three dominant amorphous clusters of deformation point sources. Predictions generated from these three point source clusters account for both the spatial and temporal complexity of the deformation patterns of the InSAR data. Regularized time series of source strength attribute a distinctive transient behavior to each of the three source clusters. A model that combines magma influx, thermoelastic relaxation, poroelastic effects, and petrologic data accounts for the transient, interrelated behavior of the source clusters and the observed deformation. Basaltic magma pulses, which flow into a storage chamber residing in the lower crust, drive this deformational system. A portion of a magma pulse is injected into the upper crust and remains in storage during both coeruption and posteruption intervals. This injected magma degasses and the volatile products accumulate in a shallow poroelastic storage chamber. During the eruption, another portion of the magma pulse is transported directly to the surface via a conduit roughly centered beneath Pyre Peak on the west side of the island. A small amount of this magma remains in storage during the eruption, and posteruption thermoelastic contraction ensues. This model, made possible by the excellent spatial and temporal coverage of the InSAR data, reveals a relatively simple system of interrelated predictable processes driven by magma dynamics.

  6. Geochemical Characteristics of the Lavas from the "Adventive Cones" of Piton de La Fournaise Volcano (La Reunion Island)

    NASA Astrophysics Data System (ADS)

    Valer, M.; Bachelery, P.; Schiano, P.; Upton, B. G. J.

    2015-12-01

    Piton de la Fournaise, the youngest volcano of La Réunion Island, is renowned for being frequently active. Whereas the current activity is mainly located within the "Enclos Fouqué" caldera, ~100 strombolian cones lie on the volcano's flanks, thought to date from ~300 years to a few thousand years. Our study focuses on these "adventive cones", by studying bulk-rock major and trace element compositions, mineral phase compositions and olivine-hosted melt inclusions. The Piton de la Fournaise lavas (younger than ~450 ka) have been subdivided into three compositional groups (see attached figure, and Lénat et al. 2012). Almost all recent and historical lavas belong to two of these groups: "cotectic basalts" and "olivine-rich basalts", marked by a constant CaO/Al2O3 ratio of ~0.8, and MgO content ranging from 5 to 30 wt % reflecting different degrees of olivine accumulation. The third group, called here "mid-alkaline basalts", corresponds to compositions commonly encountered for the "adventive cones". It mainly consists of magnesian basalts at 7.55 - 10.24 wt% MgO and CaO/Al2O3 values down to 0.55. At constant MgO content, this group shows higher alkali content and a relative deficiency in Ca compared to the historic basalts. The "adventive cones" lavas usually contain magnesian olivines (Fo > 86). Such crystals are not at the equilibrium with their host lava, raising thus the question of the recycling processes. According to Bureau et al. (1998; 1999), magnesian olivines come from deep storage levels. The specific geochemistry of the "adventive cones" lavas is attributed either to a high-pressure fractionation of a clinopyroxene-rich assemblage (Albarède et al. 1997), or to an assimilation process involving wehrlite-gabbro cumulates (e.g. Salaün et al. 2010). Our new data show that the source of these magmas is chemically homogeneous to that of current magmas. However, their ascent clearly bypasses the current lava reservoirs, especially the shallow magma chamber.

  7. Zn isotope compositions of the thermal spring waters of La Soufrière volcano, Guadeloupe Island

    NASA Astrophysics Data System (ADS)

    Chen, Jiu-Bin; Gaillardet, Jérôme; Dessert, Céline; Villemant, Benoit; Louvat, Pascale; Crispi, Olivier; Birck, Jean-Louis; Wang, Yi-Na

    2014-02-01

    To trace the sources and pathways of Zn in hydrothermal systems, the Zn isotope compositions of seventeen water samples from eight thermal springs and six gas samples from two fumaroles from La Soufrière, an active volcano on Guadeloupe Island (French West Indies, FWI), were analyzed using a method adapted for purifying Zn from Fe- and SO4-enriched thermal solutions. The fumaroles are enriched in Zn 100 to 8000 times compared to the local bedrock and have isotopic compositions (δ66Zn values from +0.21‰ to +0.35‰) similar to or slightly higher than fresh andesite (+0.21‰). The enrichment of Zn in the thermal springs compared with the surface waters shows that Zn behaves as a soluble element during hydrothermal alteration but is significantly less mobile than Na. The δ66Zn values of most of the spring waters are relatively constant (approximately 0.70‰), indicating that the thermal springs from La Soufrière are enriched in heavy isotopes (i.e., 66Zn) compared to the host rocks (from -0.14‰ to +0.42‰). Only three thermal springs have lower δ66Zn values (as low as -0.43%). While the Zn in the fumaroles is essentially derived from magma degassing, which is consistent with a previous study on Merapi volcano (Toutain et al., 2008), we show that the Zn in the thermal springs is mainly derived from water-rock interactions. The 66Zn-enriched isotopic signature in most of the spring waters can be explained qualitatively by the precipitation at depth of sulfide minerals that preferentially incorporate the light isotopes. This agrees with the isotopic fractionation that was recently calculated for aqueous complexes of Zn. The few thermal springs with lower δ66Zn values also have low Zn concentrations, indicating the preferential scavenging of heavy Zn isotopes in the hydrothermal conduits. This study shows that unlike chemical weathering under surface conditions, hydrothermal alteration at high temperatures significantly fractionates Zn isotopes and enriches

  8. 2009 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Neal, Christina A.; Girina, Olga A.; Chibisova, Marina; Rybin, Alexander

    2014-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, volcanic unrest, and reports of unusual activity at or near eight separate volcanic centers in Alaska during 2009. The year was highlighted by the eruption of Redoubt Volcano, one of three active volcanoes on the western side of Cook Inlet and near south-central Alaska's population and commerce centers, which comprise about 62 percent of the State's population of 710,213 (2010 census). AVO staff also participated in hazard communication and monitoring of multiple eruptions at ten volcanoes in Russia as part of its collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  9. Biodegradation of crude oil by thermophilic bacteria isolated from a volcano island.

    PubMed

    Meintanis, Christos; Chalkou, Kalliopi I; Kormas, Konstantinos Ar; Karagouni, Amalia D

    2006-03-01

    One-hundred and fifty different thermophilic bacteria isolated from a volcanic island were screened for detection of an alkane hydroxylase gene using degenerated primers developed to amplify genes related to the Pseudomonas putida and Pseudomonas oleovorans alkane hydroxylases. Ten isolates carrying the alkJ gene were further characterized by 16s rDNA gene sequencing. Nine out of ten isolates were phylogenetically affiliated with Geobacillus species and one isolate with Bacillus species. These isolates were able to grow in liquid cultures with crude oil as the sole carbon source and were found to degrade long chain crude oil alkanes in a range between 46.64% and 87.68%. Results indicated that indigenous thermophilic hydrocarbon degraders of Bacillus and Geobacillus species are of special significance as they could be efficiently used for bioremediation of oil-polluted soil and composting processes. PMID:16456612

  10. Chronic exposure to volcanic air pollution and DNA damage in Furnas Volcano (São Miguel Island, Azores, Portugal) inhabitants

    NASA Astrophysics Data System (ADS)

    Linhares, Diana; Garcia, Patricia; Silva, Catarina; Ferreira, Teresa; Barroso, Joana; Camarinho, Ricardo; Rodrigues, Armindo

    2015-04-01

    Many studies in volcanic air pollution only have in consideration the acute toxic effects of gas or ash releases however the impact of chronic exposure to ground gas emissions in human health is yet poorly known. In the Azores archipelago (Portugal), São Miguel island has one of the most active and dangerous volcanoes: Furnas Volcano. Highly active fumarolic fields, hot springs and soil diffuse degassing phenomena are the main secondary volcanic phenomena that can be seen at the volcano surroundings. One of the main gases released in these diffuse degassing areas is radon (222Rn), which decay results in solid particles that readily settle within the airways. These decay particles emit alpha radiation that is capable of causing severe DNA damage that cumulatively can eventually cause cancer. Previous studies have established that chronic exposure to chromosome-damaging agents can lead to the formation of nuclear anomalies, such as micronuclei that is used for monitoring DNA damage in human populations. The present study was designed to evaluate whether chronic exposure to volcanic air pollution, associated to 222Rn, might result in DNA damage in human oral epithelial cells. A cross sectional study was performed in a study group of 142 individuals inhabiting an area where volcanic activity is marked by active fumarolic fields and soil degassing (hydrothermal area), and a reference group of 368 individuals inhabiting an area without these secondary manifestations of volcanism (non-hydrothermal area). For each individual, 1000 buccal epithelial cells were analyzed for the frequency of micronucleated cells (MNc) and the frequency of cells with other nuclear anomalies (ONA: pyknosis, karyolysis and karyorrhexis), by using the micronucleus assay. Information on lifestyle factors and an informed consent were obtained from each participant. Assessment of indoor radon was performed with the use of radon detectors. Data were analyzed with logistic regression models, adjusted

  11. Don't Forget Kīlauea: Explosive Hazards at an Ocean Island Basaltic Volcano

    NASA Astrophysics Data System (ADS)

    Swanson, D. A.; Houghton, B. F.

    2015-12-01

    Kīlauea alternates between periods of high and low magma supply rate, each period lasting centuries. The low rate is only a few percent of the high rate. High supply rate, typified by the past 200 years, leads to frequent lava flows, elevated SO2 emission, and relatively low-hazard Hawaiian-style explosive activity (lava fountains, spattering). Periods of low magma supply are very different. They accompany formation and maintenance of a deep caldera, the floor of which is at or below the water table, and are characterized by phreatomagmatic and phreatic explosive eruptions largely powered by external water. The low magma supply rate results in few lava flows and reduced SO2 output. Studies of explosive deposits from the past two periods of low magma supply (~200 BCE-1000 CE and ~1500-1800 CE) indicate that VEIs calculated from isopach maps can range up to a low 3. Clast-size studies suggest that subplinian column heights can reach >10 km (most recently in 1790), though more frequent column heights are ~5-8 km. Pyroclastic density currents (PDCs) present severe proximal hazards; a PDC in 1790 killed a few hundred people in an area of Hawaíi Volcanoes National Park today visited by 5000 people daily. Ash in columns less than about 5 km a.s.l. is confined to the trade-wind regime and advects southwest. Ash in higher columns enters the jet stream and is transported east and southeast of the summit caldera. Recurrence of such column heights today would present aviation hazards, which, for an isolated state dependent on air transport, could have especially deleterious economic impact. There is currently no way to estimate when a period of low magma supply, a deep caldera, and powerful explosive activity will return. Hazard assessments must take into account the cyclic nature of Kīlauea's eruptive activity, not just its present status; consequently, assessments for periods of high and low magma supply rates should be made in parallel to cover all eventualities.

  12. The September 1988 intracaldera avalanche and eruption at Fernandina volcano, Galapagos Islands

    USGS Publications Warehouse

    Chadwick, W.W.; De Roy, T.; Carrasco, A.

    1991-01-01

    During 14-16 September 1988, a large intracaldera avalanche and an eruption of basaltic tephra and lava at Fernandina volcano, Galapagos, produced the most profound changes within the caldera since its collapse in 1968. A swarm of eight earthquakes (mb 4.7-5.5) occurred in a 14 h period on 24 February 1988 at Fernandina, and two more earthquakes of this size followed on 15 April and 20 May, respectively. On 14 September 1988, another earthquake (mb 4.6) preceded a complex series of events. A debris avalanche was generated by the failure of a fault-bounded segment of the east caldera wall, approximately 2 km long and 300 m wide. The avalanche deposit is up to 250 m thick and has an approximate volume of 0.9 km3. The avalanche rapidly displaced a preexisting lake from the southeast end of the caldera floor to the northwest end, where the water washed up against the lower part of the caldera wall, then gradually seeped into the avalanche deposit and was completely gone by mid-January 1989. An eruption began in the caldera within about 1-2 h of the earthquake, producing a vigorous tephra plume for about 12 h, then lava flows during the next two days. The eruption ended late on 16 September. Most of the eruptive activity was from vents on the caldera floor near the base of the new avalanche scar. Unequivocal relative timing of events is difficult to determine, but seismic records suggest that the avalanche may have occurred 1.6 h after the earthquake, and field relations show that lava was clearly erupted after the avalanche was emplaced. The most likely sequence of events seems to be that the 1988 feeder dike intruded upward into the east caldera wall, dislocated the unstable wall block, and triggered the avalanche. The avalanche immediately exposed the newly emplaced dike and initiated the eruption. The exact cause of the earthquakes is unknown. ?? 1991 Springer-Verlag.

  13. The 2007 eruptions and caldera collapse of the Piton de la Fournaise volcano (La Réunion Island) from tilt analysis at a single very broadband seismic station

    NASA Astrophysics Data System (ADS)

    Fontaine, Fabrice R.; Roult, Geneviève; Michon, Laurent; Barruol, Guilhem; Muro, Andrea Di

    2014-04-01

    Seismic records from La Réunion Island very broadband Geoscope station are investigated to constrain the link between the 2007 eruptive sequence and the related caldera collapse of the Piton de la Fournaise volcano. Tilt estimated from seismic records reveals that the three 2007 eruptions belong to a single inflation-deflation cycle. Tilt trend indicates that the small-volume summit eruption of 18 February occurred during a phase of continuous inflation that started in January 2007. Inflation decelerated 24 days before a second short-lived, small-volume eruption on 30 March, almost simultaneous with a sudden, large-scale deflation of the volcano. Deflation rate, which had stabilized at relatively low level, increased anew on 1 April while no magma was erupted, followed on 2 April by a major distal eruption and on 5 April by a summit caldera collapse. Long-term tilt variation suggests that the 2007 eruptive succession was triggered by a deep magma input.

  14. In-situ chemical, U-Pb dating, and Hf isotope investigation of megacrystic zircons, Malaita (Solomon Islands): Evidence for multi-stage alkaline magmatic activity beneath the Ontong Java Plateau

    NASA Astrophysics Data System (ADS)

    Simonetti, Antonio; Neal, Clive R.

    2010-06-01

    Previous investigations of pipe-like intrusions of alnöite within northern Malaita (Solomon Islands) have detailed the chemical and isotopic nature of the alnöite and entrained megacrysts/xenoliths. Alnöite emplacement is poorly constrained since available ages include an Ar-Ar date of 34 Ma (phlogopite) from a mantle xenolith, and a 206Pb/238U date of 33.9 Ma for a zircon megacryst. Hence, we report chemical data, in-situ U-Pb age determinations and Hf isotope compositions for megacrystic zircons recovered from alnöite-derived, ilmenite-rich gravels in the Auluta, Kwainale, and Faufaumela rivers of Malaita. The Zr/Hf ratio (39 to 50) is variable for zircons from Auluta and Faufaumela, whereas it is relatively uniform (40 to 42) in most zircons from Kwainale. Chemical imaging reveals the homogeneous nature for all of the 16 grains analyzed. Trace element compositions obtained by LA-ICP-MS indicate parallel chondrite-normalized REE patterns at variable levels of enrichment; these patterns combined with their low abundances (< 1 to 10 ppm) of U, Th, and Pb confirm their mantle origin. In-situ U-Pb dating conducted by LA-ICP-MS (n = 94 analyses) define a total range in weighted mean (WM) 206Pb/238U ages between ∼ 35 and ∼ 52 Ma. The zircons from Auluta define a range of WM 206Pb/238U ages between 34.9 ± 2.0 Ma and 45.1 ± 2.5 Ma (2σ) that correlate negatively with Zr/Hf ratios and total REE contents. Conversely, the chemically homogeneous zircons from Kwainale define a uniform age spectrum yielding a WM 206Pb/238U age of 36.7 ± 0.5 Ma (2σ). In-situ Hf isotope analyses (n = 30) are uniform and define a WM 176Hf/177Hf value of 0.282933 ± 0.000013 (2σ), which is identical to the previously reported whole rock value for the Malaitan alnöite (0.282939 ± 0.000007). Correlations between ages and chemical compositions (i.e., Auluta zircons), and the uniform Hf isotope compositions are consistent with zircon formation from a common Ontong Java Plateau (OJP

  15. A large proportion of asymptomatic Plasmodium infections with low and sub-microscopic parasite densities in the low transmission setting of Temotu Province, Solomon Islands: challenges for malaria diagnostics in an elimination setting

    PubMed Central

    2010-01-01

    Background Many countries are scaling up malaria interventions towards elimination. This transition changes demands on malaria diagnostics from diagnosing ill patients to detecting parasites in all carriers including asymptomatic infections and infections with low parasite densities. Detection methods suitable to local malaria epidemiology must be selected prior to transitioning a malaria control programme to elimination. A baseline malaria survey conducted in Temotu Province, Solomon Islands in late 2008, as the first step in a provincial malaria elimination programme, provided malaria epidemiology data and an opportunity to assess how well different diagnostic methods performed in this setting. Methods During the survey, 9,491 blood samples were collected and examined by microscopy for Plasmodium species and density, with a subset also examined by polymerase chain reaction (PCR) and rapid diagnostic tests (RDTs). The performances of these diagnostic methods were compared. Results A total of 256 samples were positive by microscopy, giving a point prevalence of 2.7%. The species distribution was 17.5% Plasmodium falciparum and 82.4% Plasmodium vivax. In this low transmission setting, only 17.8% of the P. falciparum and 2.9% of P. vivax infected subjects were febrile (≥38°C) at the time of the survey. A significant proportion of infections detected by microscopy, 40% and 65.6% for P. falciparum and P. vivax respectively, had parasite density below 100/μL. There was an age correlation for the proportion of parasite density below 100/μL for P. vivax infections, but not for P. falciparum infections. PCR detected substantially more infections than microscopy (point prevalence of 8.71%), indicating a large number of subjects had sub-microscopic parasitemia. The concordance between PCR and microscopy in detecting single species was greater for P. vivax (135/162) compared to P. falciparum (36/118). The malaria RDT detected the 12 microscopy and PCR positive P

  16. 2007 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Neal, Christina A.; Dixon, James P.; Malik, Nataliya; Chibisova, Marina

    2011-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest at or near nine separate volcanic centers in Alaska during 2007. The year was highlighted by the eruption of Pavlof, one of Alaska's most frequently active volcanoes. Glaciated Fourpeaked Mountain, a volcano thought to have been inactive in the Holocene, produced a phreatic eruption in the autumn of 2006 and continued to emit copious amounts of steam and volcanic gas into 2007. Redoubt Volcano showed the first signs of the unrest that would unfold in 2008-09. AVO staff also participated in hazard communication and monitoring of multiple eruptions at seven volcanoes in Russia as part of its collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  17. 2008 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; McGimsey, Robert G.; Dixon, James P.; Cameron, Cheryl E.; Nuzhdaev, Anton A.; Chibisova, Marina

    2011-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest or suspected unrest at seven separate volcanic centers in Alaska during 2008. Significant explosive eruptions at Okmok and Kasatochi Volcanoes in July and August dominated Observatory operations in the summer and autumn. AVO maintained 24-hour staffing at the Anchorage facility from July 12 through August 28. Minor eruptive activity continued at Veniaminof and Cleveland Volcanoes. Observed volcanic unrest at Cook Inlet's Redoubt Volcano presaged a significant eruption in the spring of 2009. AVO staff also participated in hazard communication regarding eruptions or unrest at nine volcanoes in Russia as part of a collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  18. Variability In The Solomon Sea From Altimetric Sea Level Data

    NASA Astrophysics Data System (ADS)

    Melet, A.; Gourdeau, L.; Kessler, W.; Verron, J.

    2007-12-01

    In the southwest tropical Pacific, subtropical waters from the SEC flow in the Solomon Sea, mainly through the western boundary New Guinea Coastal Undercurrent, and join the equatorial western Pacific by three narrow straits. The NGCU transports part of the spiciness anomalies generated in the South East Pacific and subducted in the thermocline. Because the NGCU is a primary source of the EUC, variations of its characteristics are expected to play a role in the equatorial thermocline features and more generally on decadal climate variability. Therefore, the study of the Solomon Sea is a key issue of the SPICE program. In this study, we focus on the variability of the Solomon Sea in term of sea level. The Solomon Sea is semi closed with a complex topography and numerous islands. Thus, the use of classical gridded altimetric products is inadequate. Consequently, this work is based on original along track Topex/Poseidon data. New data processing (CTOH/LEGOS) has been applied to recover proper data and to gain more information on the altimetric signal in this region. A track-by-track specific and customized post processing has been used to finalize the dataset. These new altimetric data have been assessed against tide gauge data. The analysis of the resulting sea level anomalies exhibits the highest variability observed in the tropical Pacific in an area centred near 8°S and expanding from each side of the Solomon Islands, outside of the WBC. Sea level variability presents a wide temporal spectrum, from intraseasonal to interannual ranges with the notable influence of the monsoon and of ENSO. In the Solomon Sea, three frequencies emerge : 60, 365 and 2000 days. The 60-days frequency seems particularly important in the Solomon Sea compared with the surrounding waters and an EOF analysis is used to understand its features. We also depict the signature of the New Guinea Coastal Current (NGCC), the western boundary current flowing north along the eastern coast of Papua

  19. Evaluation of noise level and site response at Mt. Etna volcano and Aeolian Islands

    NASA Astrophysics Data System (ADS)

    D Amico, S.; Giampiccolo, E.; Maiolino, V.; Patanè, D.; Ursino, A.

    2003-04-01

    The aim of this work was to test the quality of the sites where the stations of the INGV-CT seismic network are installed. This because most of the installations will be soon improved with new broad-band sensors, which require a low level of background noise. Therefore, we investigated the noise level and estimated the site response at the seismic stations deployed at Mt. Etna and at Aeolian Islands, in order to evidence possible disturbs which can be related to anthropic activity, environmental factors and/or to the local soil conditions. Noise measurements were carried out using a portable digital seismic station equipped with a 3-component, 20 s sensor. The acquisition was performed both inside the vault structures where the remote stations are located and in proximity of them, on the outcropping terrain. The noise spectra were compared with the NLNM (New Low Noise Model) and NHNM (New High Noise Model) models described by Peterson (1993). A preliminary estimate of site response at each station, by applying the Nakamura (1989) technique, was also performed. The obtained results show, for some stations, higher noise levels mainly due to volcanic tremor and/or bad soil conditions. Moreover, in several cases, vault design need to be deeply reviewed and for some installations the substitution of the sites is required. References Nakamura, Y., (1989). A method for dynamic characteristics estimation of subsurface using microtremor on the ground surface. Quarterly R of Report RTRI, 30, 25-33. Peterson, J., (1993). Observations and modelling of background seismic noise. Open File Report 93-322, U. S. Geological Survey, Albuquerque, NM.

  20. 2006 Volcanic Activity in Alaska, Kamchatka, and the Kurile Islands: Summary of Events and Response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; McGimsey, Robert G.; Dixon, James P.; Manevich, Alexander; Rybin, Alexander

    2008-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest at or near nine separate volcanic centers in Alaska during 2006. A significant explosive eruption at Augustine Volcano in Cook Inlet marked the first eruption within several hundred kilometers of principal population centers in Alaska since 1992. Glaciated Fourpeaked Mountain, a volcano thought to have been inactive in the Holocene, produced a phreatic eruption in the fall of 2006 and continued to emit copious amounts of volcanic gas into 2007. AVO staff also participated in hazard communication and monitoring of multiple eruptions at seven volcanoes in Russia as part of its collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  1. Influence of an ocean on the propagation of magmas within an oceanic basaltic shield volcano

    NASA Astrophysics Data System (ADS)

    Le Corvec, Nicolas; McGovern, Patrick

    2015-04-01

    Basaltic shield volcanoes are a common feature on Earth and mostly occur within oceans, forming volcanic islands (e.g. Hawaii (USA), Galapagos (Ecuador), and recently Niijima (Japan)). As the volcano grows it will reach and emerge from the water surface and continue to grow above it. The deformation affecting the volcanic edifice may be influenced by the presence of the water level. We investigate how the presence of an ocean affects the state of stress within a volcanic edifice and thus magma propagation and fault formation. Using COMSOL Multiphysics, axisymmetric elastic models of a volcanic edifice overlying an elastic lithosphere were created. The volcanic edifice (height of ~6000 m and radius of ~ 60 km) was built either instantaneously or iteratively by adding new layers of equivalent volume on top of each other. In the later process, the resulting stress and geometry from the one step is transferred to the next as initial conditions. Thus each new layer overlies a deformed and stressed model. The water load was modeled with a boundary condition at the surface of the model. In the case of an instantaneous volcano different water level were studied, for an iteratively growing volcano the water level was set up to 4000 m. We compared the deformation of the volcanic edifice and lithosphere and the stress orientation and magnitude in half-space and flexural models with the presence or not of an ocean. The preliminary results show 1- major differences in the resulting state of stress between an instantaneous and an iteratively built volcanic edifice, similar to the results of Galgana et al. (2011) and McGovern and Solomon (1993), respectively; 2- the presence of an ocean decreases the amount of flexural response, which decreases the magnitude of differential stress within the models; and 3- stress orientation within the volcano and lithosphere in also influence of an ocean. Those results provide new insights on the state of stress and deformation of oceanic

  2. The Variability of Refractivity in the Atmospheric Boundary Layer of a Tropical Island Volcano Measured by Ground-Based Interferometric Radar

    NASA Astrophysics Data System (ADS)

    Wadge, G.; Costa, A.; Pascal, K.; Werner, C.; Webb, T.

    2016-11-01

    For 24 h we measured continuously the variability of atmospheric refractivity over a volcano on the tropical island of Montserrat using a ground-based radar interferometer. We observed variations in phase that we interpret as due to changing water vapour on the propagation path between the radar and the volcano and we present them here in the context of the behaviour of the atmospheric boundary layer over the island. The water vapour behaviour was forced by diurnal processes, the passage of a synoptic-scale system and the presence of a plume of volcanic gas. The interferometer collected images of amplitude and phase every minute. From pairs of phase images, interferograms were calculated and analyzed every minute and averaged hourly, together with contemporaneous measurements of zenith delays estimated from a network of 14 GPS receivers. The standard deviation of phase at two sites on the volcano surface spanned a range of about 1-5 radians, the lowest values occurring at night on the lower slopes and the highest values during the day on the upper slopes. This was also reflected in spatial patterns of variability. Two-dimensional profiles of radar-measured delays were modelled using an atmosphere with water vapour content decreasing upwards and water vapour variability increasing upwards. Estimates of the effect of changing water vapour flux from the volcanic plume indicate that it should contribute only a few percent to this atmospheric variability. A diurnal cycle within the lower boundary layer producing a turbulence-dominated mixed layer during the day and stable layers at night is consistent with the observed refractivity.

  3. The Variability of Refractivity in the Atmospheric Boundary Layer of a Tropical Island Volcano Measured by Ground-Based Interferometric Radar

    NASA Astrophysics Data System (ADS)

    Wadge, G.; Costa, A.; Pascal, K.; Werner, C.; Webb, T.

    2016-06-01

    For 24 h we measured continuously the variability of atmospheric refractivity over a volcano on the tropical island of Montserrat using a ground-based radar interferometer. We observed variations in phase that we interpret as due to changing water vapour on the propagation path between the radar and the volcano and we present them here in the context of the behaviour of the atmospheric boundary layer over the island. The water vapour behaviour was forced by diurnal processes, the passage of a synoptic-scale system and the presence of a plume of volcanic gas. The interferometer collected images of amplitude and phase every minute. From pairs of phase images, interferograms were calculated and analyzed every minute and averaged hourly, together with contemporaneous measurements of zenith delays estimated from a network of 14 GPS receivers. The standard deviation of phase at two sites on the volcano surface spanned a range of about 1-5 radians, the lowest values occurring at night on the lower slopes and the highest values during the day on the upper slopes. This was also reflected in spatial patterns of variability. Two-dimensional profiles of radar-measured delays were modelled using an atmosphere with water vapour content decreasing upwards and water vapour variability increasing upwards. Estimates of the effect of changing water vapour flux from the volcanic plume indicate that it should contribute only a few percent to this atmospheric variability. A diurnal cycle within the lower boundary layer producing a turbulence-dominated mixed layer during the day and stable layers at night is consistent with the observed refractivity.

  4. Volcanic Unrest of Fogo Volcano in 2011-2012, S.Miguel Island, Azores, Observed by Continuous and Campaign GPS Analysis

    NASA Astrophysics Data System (ADS)

    Okada, Jun; Sigmundsson, Freysteinn; Ofeigsson, Benedikt; Ferreira, Teresa; Gaspar, Joao; Lorenzo, Maria; Araujo, Joao; Rodriques, Rita

    2014-05-01

    Volcanic eruptions can occur after long time of dormancy as has been seen from the recent examples: Mount St. Helens 1980, Pinatubo 1991, Unzen 1991, Soufrière Hills volcano 1995, Chaitén 2008, and Eyjafjallajökull 2010. By utilizing space geodesy techniques, namely GNSS and InSAR, it has been reported that the inflation-deflation processes exist at several dormant volcanoes in the world, but the mechanism responsible for this phenomena is still controversial. Fundamental questions such as magma vs. hydrothermal fluids and volcanic vs. tectonic process remain unanswered in many cases. In this study, we analyze both continuous and campaign GPS data from Fogo volcano, S. Miguel Island, Azores. Although no geochemical and hydrothermal evidences for a magmatic intrusion were reported during the past seismic swarm episodes (1989, 2003-2006, and 2011-2012), geophysical data, both seismic and ground deformation, indicate possible volcanic sources. GPS time series spanned 2008-2013 period characterize tectonic plate divergence between Eurasian and Nubian, and reveal two different types of ground deformation associated with the 2011-2012 volcanic unrest of Fogo. One is the permanent edifice-scale inflation centered at NE summit which corresponds to the increase of volcano-tectonic events. Another is the subsequent minor-scale inflation-deflation reversals between Congro, a trachyte maar, east of Fogo and Furnas volcano. Calculated strain rates and GPS campaign results indicate that the 2011-2012 deformation is one order smaller than the previous unrest episode. A strong similarity exists to Matsushiro earthquake swarm (1965-1966) and Campi Flegrei volcanic unrests (1969-1972 and 1982-1984), which is the coexistence of an edifice-scale main inflation associated with intense volcano-tectonic earthquakes with inflation to deflation reversal that coincided with a sharp drop of seismicity. High recovery rate of inflation-deflation may be an indicator for the existence of

  5. Santorini Volcano

    USGS Publications Warehouse

    Druitt, T.H.; Edwards, L.; Mellors, R.M.; Pyle, D.M.; Sparks, R.S.J.; Lanphere, M.; Davies, M.; Barreirio, B.

    1999-01-01

    Santorini is one of the most spectacular caldera volcanoes in the world. It has been the focus of significant scientific and scholastic interest because of the great Bronze Age explosive eruption that buried the Minoan town of Akrotiri. Santorini is still active. It has been dormant since 1950, but there have been several substantial historic eruptions. Because of this potential risk to life, both for the indigenous population and for the large number of tourists who visit it, Santorini has been designated one of five European Laboratory Volcanoes by the European Commission. Santorini has long fascinated geologists, with some important early work on volcanoes being conducted there. Since 1980, research groups at Cambridge University, and later at the University of Bristol and Blaise Pascal University in Clermont-Ferrand, have collected a large amount of data on the stratigraphy, geochemistry, geochronology and petrology of the volcanics. The volcanic field has been remapped at a scale of 1:10 000. A remarkable picture of cyclic volcanic activity and magmatic evolution has emerged from this work. Much of this work has remained unpublished until now. This Memoir synthesizes for the first time all the data from the Cambridge/Bristol/Clermont groups, and integrates published data from other research groups. It provides the latest interpretation of the tectonic and magmatic evolution of Santorini. It is accompanied by the new 1:10 000 full-colour geological map of the island.

  6. A Stratigraphic, Granulometric, and Textural Comparison of recent pyroclastic density current deposits exposed at West Island and Burr Point, Augustine Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Rath, C. A.; Browne, B. L.

    2011-12-01

    Augustine Volcano (Alaska) is the most active volcano in the eastern Aleutian Islands, with 6 violent eruptions over the past 200 years and at least 12 catastrophic debris-avalanche deposits over the past ~2,000 years. The frequency and destructive nature of these eruptions combined with the proximity of Augustine Volcano to commercial ports and populated areas represents a significant hazard to the Cook Inlet region of Alaska. The focus of this study examines the relationship between debris-avalanche events and the subsequent emplacement of pyroclastic density currents by comparing the stratigraphic, granulometric, and petrographic characteristics of pyroclastic deposits emplaced following the 1883 A.D. Burr Point debris-avalanche and those emplaced following the ~370 14C yr B.P. West Island debris-avalanche. Data from this study combines grain size and componentry analysis of pyroclastic deposits with density, textural, and compositional analysis of juvenile clasts contained in the pyroclastic deposits. The 1883 A.D. Burr Point pyroclastic unit immediately overlies the 1883 debris avalanche deposit and underlies the 1912 Katmai ash. It ranges in thickness from 4 to 48 cm and consists of fine to medium sand-sized particles and coarser fragments of andesite. In places, this unit is normally graded and exhibits cross-bedding. Many of these samples are fines-enriched, with sorting coefficients ranging from -0.1 to 1.9 and median grain size ranging from 0.1 to 2.4 mm. The ~370 14C yr B.P. West Island pyroclastic unit is sandwiched between the underlying West Island debris-avalanche deposit and the overlying 1912 Katmai Ash deposit, and at times a fine-grained gray ash originating from the 1883 eruption. West Island pyroclastic deposit is sand to coarse-sand-sized and either normally graded or massive with sorting coefficients ranging from 0.9 to 2.8 and median grain sizes ranging from 0.4 to 2.6 mm. Some samples display a bimodal distribution of grain sizes, while

  7. Insights from geophysical monitoring into the volcano structure and magma supply systems at three very different oceanic islands in the Cape Verde archipelago

    NASA Astrophysics Data System (ADS)

    Faria, B. V.; Day, S.; Fonseca, J. F.

    2013-12-01

    Three oceanic volcano islands in the west of the Cape Verde archipelago are considered to have the highest levels of volcanic hazard in the archipelago: Fogo, Brava, and Santo Antao. Fogo has had frequent mainly effusive eruptions in historic time, the most recent in 1995, whilst Brava and Santo Antao have ongoing geothermal activity and felt earthquakes, and have experienced geologically recent violent explosive eruptions. Therefore, these three islands have been the focus of recent efforts to set up seismic networks to monitor their activity. Here we present the first results from these networks, and propose interpretations of the monitored seismic activity in terms of subsurface volcano structures, near-surface intrusive activity and seasonal controls on geothermal activity. In Fogo, most recorded seismic events are hydrothermal events. These show a strong seasonal variation, increasing during the summer rain season and decreasing afterwards. Rare volcano-tectonic (VT) events (0.1island due to the 1995 eruption. Brava experiences frequent swarms of VT events. These are located mostly offshore, with a small proportion of on-shore events. The positions of offshore events are strongly correlated with seamounts and hence are interpreted as due to submarine volcanic processes. Onshore events (0.7island that has been indicated by previous geological studies, and may be due to inflation of a magma reservoir in the edifice. S. Antão is characterized by frequent seismic swarms composed of VT earthquakes (0.1

  8. Preliminary volcano-hazard assessment for Kanaga Volcano, Alaska

    USGS Publications Warehouse

    Waythomas, Christopher F.; Miller, Thomas P.; Nye, Christopher J.

    2002-01-01

    Kanaga Volcano is a steep-sided, symmetrical, cone-shaped, 1307 meter high, andesitic stratovolcano on the north end of Kanaga Island (51°55’ N latitude, 177°10’ W longitude) in the western Aleutian Islands of Alaska. Kanaga Island is an elongated, low-relief (except for the volcano) island, located about 35 kilometers west of the community of Adak on Adak Island and is part of the Andreanof Islands Group of islands. Kanaga Volcano is one of the 41 historically active volcanoes in Alaska and has erupted numerous times in the past 11,000 years, including at least 10 eruptions in the past 250 years (Miller and others, 1998). The most recent eruption occurred in 1993-95 and caused minor ash fall on Adak Island and produced blocky aa lava flows that reached the sea on the northwest and west sides of the volcano (Neal and others, 1995). The summit of the volcano is characterized by a small, circular crater about 200 meters in diameter and 50-70 meters deep. Several active fumaroles are present in the crater and around the crater rim. The flanking slopes of the volcano are steep (20-30 degrees) and consist mainly of blocky, linear to spoonshaped lava flows that formed during eruptions of late Holocene age (about the past 3,000 years). The modern cone sits within a circular caldera structure that formed by large-scale collapse of a preexisting volcano. Evidence for eruptions of this preexisting volcano mainly consists of lava flows exposed along Kanaton Ridge, indicating that this former volcanic center was predominantly effusive in character. In winter (October-April), Kanaga Volcano may be covered by substantial amounts of snow that would be a source of water for lahars (volcanic mudflows). In summer, much of the snowpack melts, leaving only a patchy distribution of snow on the volcano. Glacier ice is not present on the volcano or on other parts of Kanaga Island. Kanaga Island is uninhabited and is part of the Alaska Maritime National Wildlife Refuge, managed by

  9. The petrogenesis of island arc basalts from Gunung Slamet volcano, Indonesia: Trace element and 87Sr /86Sr contraints

    NASA Astrophysics Data System (ADS)

    Vukadinovic, Danilo; Nicholls, Ian A.

    1989-09-01

    Selected major and trace elements, rare earth element (REE) and 87Sr /86Sr data are presented for arc basalts from Gunung Slamet volcano, Java, Indonesia. On the basis of stratigraphy, trace element content, Zr/Nb, and 87Sr /86Sr ratios, Slamet basalts can be broadly categorized into high abundance magma (HAM) and low abundance magma (LAM) types. Provided the quantities of 'immobile' trace elements (in aqueous systems) such as Nb, Hf and Zr in the mantle wedge and ensuing magmas are unaffected by additions from subducted lithosphere or overlying arc crust, a model may be developed whereby LAM are generated by higher degrees of melting in the mantle wedge (13%) compared to HAM (7%). Hf/Nb or Zr/Nb ratio systematics indicate that prior to metasomatism by the underlying lithosphere, the Slamet mantle wedge was similar in chemical character to transitional-MORB source mantle. Conversely, examination of immobile/mobile incompatible trace element ratios (IMITER) provide clues to the nature of the metasomatizing agent, most likely derived from the subducted slab (basalts and sediments). HAM have constant IMITER ( e.g.Nb/U, Zr/K), whereas LAM show a negative correlation between IMITER and 87Sr /86Sr . Metasomatism of the mantle wedge was modelled by interaction with either a slab-derived-melt or -aqueous fluid. Yb/Sr and 87Sr /86Sr ratios from Slamet basalts and oceanic sediments suggest that 'bulk' mixing of the latter into the mantle wedge is unlikely. Instead, sediments probably interact with overlying mantle in the same way that subducted basalts do-either as melts or fluids. In the case of slab-derived melts mixing with 'pristine' mantle, good agreement with back-calculated values for HAM and LAM sources can be achieved only if a residual phase such as rutile persists in the subducting lithosphere. In the case of fluids, excellent agreement with back-calculated values is obtained for all elements except heavy REE. It is tentatively suggested that aqueous slab

  10. Three-dimensional shear velocity anisotropic model of Piton de la Fournaise Volcano (La Réunion Island) from ambient seismic noise

    NASA Astrophysics Data System (ADS)

    Mordret, Aurélien; Rivet, Diane; Landès, Matthieu; Shapiro, Nikolaï M.

    2015-01-01

    We cross correlate 4 years of seismic noise from the seismic network of Piton de la Fournaise Volcano (La Réunion Island) to measure the group velocity dispersion curves of Rayleigh and Love waves. We average measurements from vertical and radial components to obtain 577 Rayleigh wave dispersion curves. The transverse components provided 395 Love wave dispersion curves. We regionalize the group velocities measurements into 2-D velocity maps between 0.4 and 8 s. Finally, we locally inverted these maps for a pseudo 3-D anisotropic shear-velocity model down to 3 km below the sea level using a Neighborhood Algorithm. The 3-D isotropic shear-wave model shows three distinct high-velocity anomalies surrounded by a low-velocity ring. The anomaly located below the present "Plaine des Sables" could be related to an old intrusive body at the location of the former volcanic center before it migrated toward its present location. The second high-velocity body located below the summit of the volcano likely corresponds to the actual preferential dyke intrusion zone as highlighted by the seismicity. The third high-velocity anomaly located below the "Grandes Pentes" and the "Grand Brûlé" areas and is an imprint of the solidified magma chamber of the dismantled "Les Alizés" Volcano. Radial anisotropy shows two main anomalies: positive anisotropy above sea level highlighting the recent edifice of Piton de la Fournaise with an accumulation of horizontal lava flows and the second one below the sea level with a negative anisotropy corresponding to the ancient edifice of Piton de la Fournaise dominated by intrusions of vertical dykes.

  11. Volcanic-ash hazard to aviation during the 2003 2004 eruptive activity of Anatahan volcano, Commonwealth of the Northern Mariana Islands

    NASA Astrophysics Data System (ADS)

    Guffanti, Marianne; Ewert, John W.; Gallina, Gregory M.; Bluth, Gregg J. S.; Swanson, Grace L.

    2005-08-01

    Within the Commonwealth of the Northern Mariana Islands (CNMI), Anatahan is one of nine active subaerial volcanoes that pose hazards to major air-traffic routes from airborne volcanic ash. The 2003-2004 eruptive activity of Anatahan volcano affected the region's aviation operations for 3 days in May 2003. On the first day of the eruption (10 May 2003), two international flights from Saipan to Japan were cancelled, and several flights implemented ash-avoidance procedures. On 13 May 2003, a high-altitude flight through volcanic gas was reported, with no perceptible damage to the aircraft. TOMS and MODIS analysis of satellite data strongly suggests that no significant ash and only minor amounts of SO 2 were involved in the incident, consistent with crew observations. On 23 May 2003, airport operations were disrupted when tropical-cyclone winds dispersed ash to the south, dusting Saipan with light ashfall and causing flight cancellations there and at Guam 320 km south of the volcano. Operational (near-real-time) monitoring of ash clouds produced by Anatahan has been conducted since the first day of the eruption on 10 May 2003 by the Washington Volcanic Ash Advisory Center (VAAC). The VAAC was among the first groups outside of the immediate area of the volcano to detect and report on the unexpected eruption of Anatahan. After being contacted about an unusual cloud by National Weather Service forecasters in Guam at 1235 UTC on 10 May 2003, the VAAC analyzed GOES 9 images, confirming Anatahan as the likely source of an ash cloud and estimating that the eruption began at about 0730 UTC. The VAAC issued its first Volcanic Ash Advisory for Anatahan at 1300 UTC on 10 May 2003 more than 5 h after the start of the eruption, the delay reflecting the difficulty of detecting and confirming a surprise eruption at a remote volcano with no in situ real-time geophysical monitoring. The initial eruption plume reached 10.7-13.4 km (35,000-44,000 ft), well into jet cruise altitudes

  12. Volcanic-ash hazard to aviation during the 2003-2004 eruptive activity of Anatahan volcano, Commonwealth of the Northern Mariana Islands

    USGS Publications Warehouse

    Guffanti, M.; Ewert, J.W.; Gallina, G.M.; Bluth, G.J.S.; Swanson, G.L.

    2005-01-01

    Within the Commonwealth of the Northern Mariana Islands (CNMI), Anatahan is one of nine active subaerial volcanoes that pose hazards to major air-traffic routes from airborne volcanic ash. The 2003-2004 eruptive activity of Anatahan volcano affected the region's aviation operations for 3 days in May 2003. On the first day of the eruption (10 May 2003), two international flights from Saipan to Japan were cancelled, and several flights implemented ash-avoidance procedures. On 13 May 2003, a high-altitude flight through volcanic gas was reported, with no perceptible damage to the aircraft. TOMS and MODIS analysis of satellite data strongly suggests that no significant ash and only minor amounts of SO2 were involved in the incident, consistent with crew observations. On 23 May 2003, airport operations were disrupted when tropical-cyclone winds dispersed ash to the south, dusting Saipan with light ashfall and causing flight cancellations there and at Guam 320 km south of the volcano. Operational (near-real-time) monitoring of ash clouds produced by Anatahan has been conducted since the first day of the eruption on 10 May 2003 by the Washington Volcanic Ash Advisory Center (VAAC). The VAAC was among the first groups outside of the immediate area of the volcano to detect and report on the unexpected eruption of Anatahan. After being contacted about an unusual cloud by National Weather Service forecasters in Guam at 1235 UTC on 10 May 2003, the VAAC analyzed GOES 9 images, confirming Anatahan as the likely source of an ash cloud and estimating that the eruption began at about 0730 UTC. The VAAC issued its first Volcanic Ash Advisory for Anatahan at 1300 UTC on 10 May 2003 more than 5 h after the start of the eruption, the delay reflecting the difficulty of detecting and confirming a surprise eruption at a remote volcano with no in situ real-time geophysical monitoring. The initial eruption plume reached 10.7-13.4 km (35,000-44,000 ft), well into jet cruise altitudes

  13. Preliminary volcano-hazard assessment for Great Sitkin Volcano, Alaska

    USGS Publications Warehouse

    Waythomas, Christopher F.; Miller, Thomas P.; Nye, Christopher J.

    2003-01-01

    Great Sitkin Volcano is a composite andesitic stratovolcano on Great Sitkin Island (51°05’ N latitude, 176°25’ W longitude), a small (14 x 16 km), circular volcanic island in the western Aleutian Islands of Alaska. Great Sitkin Island is located about 35 kilometers northeast of the community of Adak on Adak Island and 130 kilometers west of the community of Atka on Atka Island. Great Sitkin Volcano is an active volcano and has erupted at least eight times in the past 250 years (Miller and others, 1998). The most recent eruption in 1974 caused minor ash fall on the flanks of the volcano and resulted in the emplacement of a lava dome in the summit crater. The summit of the composite cone of Great Sitkin Volcano is 1,740 meters above sea level. The active crater is somewhat lower than the summit, and the highest point along its rim is about 1,460 meters above sea level. The crater is about 1,000 meters in diameter and is almost entirely filled by a lava dome emplaced in 1974. An area of active fumaroles, hot springs, and bubbling hot mud is present on the south flank of the volcano at the head of Big Fox Creek (see the map), and smaller ephemeral fumaroles and steam vents are present in the crater and around the crater rim. The flanking slopes of the volcano are gradual to steep and consist of variously weathered and vegetated blocky lava flows that formed during Pleistocene and Holocene eruptions. The modern edifice occupies a caldera structure that truncates an older sequence of lava flows and minor pyroclastic rocks on the east side of the volcano. The eastern sector of the volcano includes the remains of an ancestral volcano that was partially destroyed by a northwest-directed flank collapse. In winter, Great Sitkin Volcano is typically completely snow covered. Should explosive pyroclastic eruptions occur at this time, the snow would be a source of water for volcanic mudflows or lahars. In summer, much of the snowpack melts, leaving only a patchy

  14. Phylogeography of the prehensile-tailed skink Corucia zebrata on the Solomon Archipelago

    PubMed Central

    Hagen, Ingerid J; Donnellan, Stephen C; Bull, C Michael

    2012-01-01

    The biogeography of islands is often strongly influenced by prior geological events. Corucia zebrata (Squamata: Scincidae) is endemic to the geologically complex Solomon Archipelago in Northern Melanesia. We examined the level of divergence for different island populations of C. zebrata and discussed these patterns in light of Pleistocene land bridges, island isolation, and island age. Corucia zebrata was sampled from 14 locations across the Solomon Archipelago and sequenced at two mitochondrial genes (ND2 and ND4; 1697 bp in total) and four nuclear loci (rhodopsin, an unknown intron, AKAP9, and PTPN12). Measures of genetic divergence, analyses of genetic variation, and Bayesian phylogenetic inference were used and the data assessed in light of geological information. Populations of C. zebrata on separate islands were found to be genetically different from each other, with reciprocal monophyly on mitochondrial DNA. Populations on islands previously connected by Pleistocene land bridges were marginally less divergent from each other than from populations on other nearby but isolated islands. There are indications that C. zebrata has radiated across the eastern islands of the archipelago within the last 1–4 million years. Nuclear loci were not sufficiently informative to yield further information about the phylogeography of C. zebrata on the Solomon Archipelago. Analyses of the mitochondrial data suggest that dispersal between islands has been very limited and that there are barriers to gene flow within the major islands. Islands that have been isolated during the Pleistocene glacial cycles are somewhat divergent in their mitochondrial genotypes, however, isolation by distance (IBD) and recent colonization of isolated but geologically younger islands appear to have had stronger effects on the phylogeography of C. zebrata than the Pleistocene glacial cycles. This contrasts with patterns reported for avian taxa, and highlights the fact that biogeographic regions for

  15. A new model for the growth of basaltic shields based on deformation of Fernandina volcano, Galápagos Islands

    USGS Publications Warehouse

    Bagnardi, Marco; Amelung, Falk; Poland, Michael P.

    2013-01-01

    Space-geodetic measurements of surface deformation produced by the most recent eruptions at Fernandina – the most frequently erupting volcano in the Galápagos Archipelago – reveal that all have initiated with the intrusion of subhorizontal sills from a shallow magma reservoir. This includes eruptions from fissures that are oriented both radially and circumferentially with respect to the summit caldera. A Synthetic Aperture Radar (SAR) image acquired 1–2 h before the start of a radial fissure eruption in 2009 captures one of these sills in the midst of its propagation toward the surface. Galápagos eruptive fissures of all orientations have previously been presumed to be fed by vertical dikes, and this assumption has guided models of the origin of the eruptive fissure geometry and overall development of the volcanoes. Our findings allow us to reinterpret the internal structure and evolution of Galápagos volcanoes and of similar basaltic shields. Furthermore, we note that stress changes generated by the emplacement of subhorizontal sills feeding one type of eruption may control the geometry of subsequent eruptive fissures. Specifically, circumferential fissures tend to open within areas uplifted by sill intrusions that initiated previous radial fissure eruptions. This mechanism provides a possible explanation for the pattern of eruptive fissures that characterizes all the western Galápagos volcanoes, as well as the alternation between radial and circumferential fissure eruptions at Fernandina. The same model suggests that the next eruption of Fernandina will be from a circumferential fissure in the area uplifted by the 2009 sill intrusion, just southwest of the caldera rim.

  16. New K-Ar ages for calculating end-of-shield extrusion rates at West Maui volcano, Hawaiian island chain

    USGS Publications Warehouse

    Sherrod, D.R.; Murai, T.; Tagami, Takahiro

    2007-01-01

    Thirty-seven new K-Ar ages from West Maui volcano, Hawai'i, are used to define the waning stages of shield growth and a brief episode of postshield volcanism. All but two samples from shield-stage strata have reversed polarity magnetization, so conceivably the exposed shield is not much older than the Olduvai Normal-Polarity subchron, or about 1.8 Ma. The oldest ages obtained are in the range 1.9-2.1 Ma but have large analytical error. Shield volcanism ended about 1.35 Ma, and postshield volcanism followed soon thereafter, persisting until about 1.2 Ma. Exposed shield-stage strata were emplaced at a rate of about 0.001 km3 per year, a rate smaller than historic Hawaiian magmatic rates by a factor of 100. Stratigraphic accumulation rates are similar to those measured previously at Wai'anae volcano (O'ahu) or the upper part of the Mauna Kea shield sequence (Hilo drill core, Hawai'i). These rates diminish sharply during the final 0.3-0.5 m.y. of the shield stage. Hawaiian shield volcanoes begin waning well before their last 0.5 m.y. of life, then end quickly, geologically speaking, if West Maui is representative. ?? Springer-Verlag 2006.

  17. Characteristics on fault coupling along the Solomon megathrust based on GPS observations from 2011 to 2014

    NASA Astrophysics Data System (ADS)

    Kuo, Yu-Ting; Ku, Chin-Shang; Chen, Yue-Gau; Wang, Yu; Lin, Yu-Nung Nina; Chuang, Ray Y.; Hsu, Ya-Ju; Taylor, Frederick W.; Huang, Bor-Shouh; Tung, Hsin

    2016-08-01

    The Solomon megathrust along the western Solomon arc generated two megathrust earthquakes in the past decade (Mw 8.1 in 2007 and Mw 7.1 in 2010). To investigate the interseismic deformation and inferred coupling on the megathrust, we deployed the first continuous GPS network in the Western Solomon Islands. Our 2011-2014 GPS data and the back slip inversion model show coupling ratio as high as 73% along the southeastern 2007 rupture segment but only 10% on average along the segment of 2010 event. Based on the spatial distribution of coseismic slip, aftershock clusters, derived coupling pattern, and paleogeodetic records, we discovered the former as a semipermanent asperity and the latter as a potential megathrust barrier. We propose that a characteristic earthquake of magnitude not less than Mw 8 will recur in an interval of 100 or more years by either single or doublet earthquake.

  18. New Insights into the Influence of Structural Controls Affecting Groundwater Flow and Storage Within an Ocean Island Volcano, Mauna Kea, Hawaii

    NASA Astrophysics Data System (ADS)

    Thomas, D. M.; Haskins, E.; Wallin, E.; Pierce, H. A.

    2015-12-01

    The Humu'ula Groundwater Research Project was undertaken on the Island of Hawaii in an effort to characterize the hydrologic structures controlling groundwater movement and storage within Saddle region between Mauna Loa and Mauna Kea volcanoes. In 2013, the project drilled a 1764 m, continuously-cored, borehole from an elevation of 1946 m amsl near the center of the Saddle, and has now completed a second borehole at an elevation of 1645 m on the western edge of the Saddle. Although the stratigraphy of the rocks is similar, dominantly pahoehoe lava flows with somewhat fewer a'a lavas and occasional dike rock intervals, the hydrologic character of the formation in the latter is distinctly different from the former. Whereas the former test hole encountered a few high elevation perched aquifers that were underlain by an inferred regional, dike-impounded, water table at an elevation of 1390 m amsl, the latter bore encountered a sequence of confined aquifers with heads substantially higher than depth of entry. The shallowest of the confined aquifers was encountered at an elevation of 1340 m and showed a hydrostatic head of >160 m when the capping formation was breached. Deeper confined aquifers showed initial heads of > 400 m although none had heads sufficient to discharge at the surface. Most of the confined aquifers were associated with clay-rich ash beds that mantled the more permeable lavas however one of the deeper confined zones, that showed the highest head, was associated with a highly compacted breccia zone that has tentatively been ascribed to an explosive deposit. Chemical analysis of the clasts within this layer is underway to determine whether this deposit is associated with explosive activity of Mauna Kea or with another volcano on the island. Previous geophysical surveys have suggested that these confined aquifers may extend well down the leeward slopes of Mauna Kea. Evidence of multiple confining layers within the flanks of Mauna Kea suggest that its

  19. Preliminary Results on the 2015 Eruption of Wolf Volcano, Isabela Island, Galápagos: Chronology, Dispersion of the Volcanic Products, and Insight into the Eruptive Dynamics

    NASA Astrophysics Data System (ADS)

    Wright, H. M. N.; Bernard, B.; Ramon, P.; Guevara, A.; Hidalgo, S.; Pacheco, D. A.; Narváez, D.; Vásconez, F.

    2015-12-01

    After 33 years of quiescence, Wolf volcano, located in the northernmost tip of Isabela Island (Galápagos Islands, Ecuador), started a new eruption on May 25, 2015. The first signs of activity were recorded at 5:50 UTC (23:50 on May 24, Local Time in Galápagos) by a seismic station installed on Fernandina island. The first visual observation was reported at 7:38 UTC (1:38 LT). Based on amateur film footage, the vent was a >800 m-long circumferential fissure that produced a >100 m-high lava curtain. The eruption also released a 15 km-high gas plume with a large amount of SO2 and minimal ash content. Lightning was observed in the plume but not near the vent. Due to complex wind directions at high altitude, the gas cloud drifted in all directions eventually coming toward the continent and producing an extremely small ashfall in Quito that was detected only through the use of homemade ashmeters. The ash sample included lava droplets, scoria, and one small fragment of reticulite, indicating high lava fountaining during the first days of the eruption. The active vents on the circumferential fissure, initially located on the SE side of the caldera outer rim, moved progressively northward, eventually extending for a total of 2 km. One week later on June 02, satellite imagery (OMI, GOME, MODIS) documented decreased volcanic activity, leaving two new lava fields covering over 17 km2 on the SE (10 km-long and up to 2 km-wide) and E (7 km-long and up to 1 km-wide, reaching the sea) flanks of the volcano. Volcanic activity resumed on June 11, and on June 13 it shifted into the caldera, apparently emerging from a fissure close to the vent from the 1982 eruption, about 4 km W of the circumferential fissure. This new lava flow covered approximately 3.5 km2 of the caldera floor. Finally, volcanic activity waned at the end of June and appeared to have ended by July 11, accounting for one of the largest eruptions in the Galápagos since 1968 based on remote sensing.

  20. Long-term explosion records from two erupting submarine volcanoes in the Mariana and Tonga island-arcs

    NASA Astrophysics Data System (ADS)

    Dziak, R. P.; Embley, R. W.; Baker, E. T.; Chadwick, W. W.; Resing, J.; Matsumoto, H.; Walker, S. L.; Bohnenstiehl, D. R.; Klink, H.

    2009-12-01

    Records of explosive activity longer than a few weeks are rare for subaerial volcanoes, and nonexistent for submarine volcanoes. From February 2008 to February 2009, we recorded a year long, continuous acoustic and volcanic plume record from NW Rota-1, an erupting submarine volcano located within the Mariana Arc. From December 2008 to May 2009, we also obtained acoustic records of ongoing explosion and tremor activity at West Mata, a submarine volcano in the NE Lau basin near the Tofua volcanic-arc. At NW Rota-1, a hydrophone and turbidity/temperature sensor were moored ~150 m from the volcano’s summit vent (520 m deep). The volcano exhibited frequent degassing explosions lasting 60-120 s, separated by quiet periods of 10-30 s, for the entire 12-months resulting in >284,000 discrete explosion events. The explosions are broadband (1-80 Hz) with typical source levels of 191 dB re μPa @ 1m. Harmonic tremor is also present at times in the explosions, typically with <5 Hz fundamentals and extremely high-amplitude overtone peaks near 30 Hz. The fundamentals are likely due to resonance of the entire volcanic edifice, while the peak overtone may represent reverberation of an internal structure, possibly the conduit feeding the summit vent. The hydrophone also documents a 103 decrease in explosion amplitude over the year, marked by a sharp reduction after 6 mos, which may be part of the typical eruption cycle or due to burial of the vent by accumulated ejecta. Explosions at the summit vent produced a steady series of volcanic plumes that carried ash and hydrothermal precipitates into the water column. Hundreds of short-lived turbidity spikes are present, with no long periods of quiescence, indicating changes in explosion intensity did not affect the pattern of volcanic plume creation. Our data are the first to confirm the frequent creation and dispersal of submarine volcanic plumes on a year-long scale. In December 2008 a moored hydrophone (250 Hz) was deployed ~30 km

  1. Mount St. Helens and Kilauea volcanoes

    SciTech Connect

    Barrat, J. )

    1989-01-01

    Mount St. Helens' eruption has taught geologists invaluable lessons about how volcanoes work. Such information will be crucial in saving lives and property when other dormant volcanoes in the northwestern United States--and around the world--reawaken, as geologists predict they someday will. Since 1912, scientists at the U.S. Geological Survey's Hawaiian Volcano Observatory have pioneered the study of volcanoes through work on Mauna Loa and Kilauea volcanoes on the island of Hawaii. In Vancouver, Wash., scientists at the Survey's Cascades Volcano Observatory are studying the after-effects of Mount St. Helens' catalysmic eruption as well as monitoring a number of other now-dormant volcanoes in the western United States. This paper briefly reviews the similarities and differences between the Hawaiian and Washington volcanoes and what these volcanoes are teaching the volcanologists.

  2. Co-variation in Magma Compositions, Effusion rates and Seismic Tremor During the 2014-15 Eruption of Fogo volcano, Cape Verde Islands

    NASA Astrophysics Data System (ADS)

    Day, S. J.

    2015-12-01

    Magma compositions vary widely within many eruptions of ocean island volcanoes, particularly those in the Canaries and Cape Verde Islands. The 23 November 2014 to 7 February 2015 eruption of Fogo in the Cape Verde Islands was the first eruption in either the Canaries or the Cape Verdes to be monitored by multiple satellite instruments that measured infrared emissions of the eruption and so enabled continuous quantitative estimation of magma effusion rates and their variation through time. It is also the first eruption in the Cape Verdes for which seismic tremor intensity, indicative of magma ascent dynamics, was continuously recorded. Effusion rates were highest, peaking at about 20 m3/s, in the first five days of eruption but later asymptotic decay in effusion rate was interrupted around 9 and 16 December by pulses of increased effusion. Activity was mainly mildly explosive from December 31, accompanied by intensified seismic tremor. A final pulse of low-rate lava effusion occurred from 17 to 22 January. These data provide a new framework within which to relate compositional variations in the eruption to variations in magma ascent and effusion. We collected a suite of samples whose dates of emplacement have been determined from the date of incandescence of each sample site in high-resolution thermal infrared emissivity maps collected by satellite during the eruption. The samples are highly porphyritic and strongly alkaline in composition, as is typical of Fogo magmas. The first- (November 23/24) and last- (January) erupted magma batches show evidence for hybridization with more evolved magma batches, and the 9 and 16 December magma pulses may be distinct from the magma erupted during the main phase of the eruption. We present data on the samples that allow us to examine the hypothesis that the effusion rate variations were controlled by tapping of different parts of the magma reservoir or reservoirs during the eruption.

  3. The growth of Ritter Island volcano, Papua New Guinea, and the lateral collapse landslide and tsunami of 1888: new insights from eyewitness accounts

    NASA Astrophysics Data System (ADS)

    Ray, Melanie Jane; Day, Simon; Downes, Hilary

    2014-05-01

    We present a case study of the 1888 edifice lateral collapse landslide and tsunami event at Ritter Island volcano, using a more complete set of primary and secondary eyewitness accounts than has been used in previous studies. The collapse, early in the morning of March 13th, 1888, removed most of the island and its western submarine flank down to the base of the edifice some 900 m below sea level. The resulting tsunami is believed to have eradicated entire coastal communities on the surrounding islands and was recorded by German colonists in several locations around the Bismarck Sea and on adjacent coasts. Our analysis, based in particular upon new and complete translation of the German accounts, considers the evolution of the island over the previous two centuries and the events of March 1888, with the aim of clarifying the constraints that exist upon the cause, kinematics and mechanisms of the lateral collapse. Our analysis indicates that the pre-collapse Ritter edifice produced frequent strombolian eruptions and steam emissions, building an approximately 1700 m wide, notably steep-sided edifice with a N-S elongated oval shape in plan, by the late 1800s. Most activity was concentrated at a group of summit craters some 800 m above sea level, possibly also in a north-south line, with lesser flank fissure activity. The accounts of the tsunami indicate that the 1888 collapse involved a single large-scale catastrophic landslide, but descriptions of the island in the following days indicate a period in which there were many small landslides from the newly formed and unstable collapse scar. There is no evidence for a sequence of large landslides during this event and there is no clear evidence for a coincident or causal magmatic explosive eruption. One report suggests that there was activity (perhaps phreatic or phreatomagmatic explosions?) prior to the collapse that lead some of the resident local communities to seek higher ground, but evidence for precursory flank

  4. Variability of passive gas emissions, seismicity, and deformation during crater lake growth at White Island Volcano, New Zealand, 2002-2006

    USGS Publications Warehouse

    Werner, C.; Hurst, T.; Scott, B.; Sherburn, S.; Christenson, B.W.; Britten, K.; Cole-Baker, J.; Mullan, B.

    2008-01-01

    We report on 4 years of airborne measurements of CO2, SO2, and H2S emission rates during a quiescent period at White Island volcano, New Zealand, beginning in 2003. During this time a significant crater lake emerged, allowing scrubbig processes to be investigated. CO2 emissions varied from a baseline of 250 to >2000 t d-1 and demonstrated clear annual cycling that was consistent with numbers of earthquake detections and annual changes in sea level. The annual variability was found to be most likely related to increases in the strain on the volcano during sea level highs, temporarily causing fractures to reduce in size in the upper conduit. SO2 emissions varied from 0 to >400 t d-1 and were clearly affected by scrubbing processes within the first year of take development. Scrubbing caused increases of SO42- and Cl- in lake waters, and the ratio of carbon to total sulphur suggested that elemental sulphur deposition was also significant in the lake during the first year. Careful measurements of the lake level and chemistry allowed estimates of the rate of H2O(g) and HCl(g) input into the lake and suggested that the molar abundances of major gas species (H2O, CO2, SO2, and HCl) during this quiescent phase were similar to fumarolic ratios observed between earlier eruptive periods. The volume of magma estimated from CO2 emissions (0.0 15-0.04 km3) was validated by Cl- increases in the lake, suggesting that the gas and magma are transported from deep to shallow depths as a closed system and likely become open in the upper conduit region. The absence of surface deformation further leads to a necessity of magma convection to supply and remove magma from the degassing depths. Two models of convection configurations are discussed. Copyright 2008 by the American Geophysical Union.

  5. Recent and Hazardous Volcanic Activity Along the NW Rift Zone of Piton De La Fournaise Volcano, La Réunion Island

    NASA Astrophysics Data System (ADS)

    Walther, G.; Frese, I.; Di Muro, A.; Kueppers, U.; Michon, L.; Metrich, N.

    2014-12-01

    Shield volcanoes are a common feature of basaltic volcanism. Their volcanic activity is often confined to a summit crater area and rift systems, both characterized by constructive (scoria and cinder cones; lava flows) and destructive (pit craters; caldera collapse) phenomena. Piton de la Fournaise (PdF) shield volcano (La Réunion Island, Indian Ocean) is an ideal place to study these differences in eruptive behaviour. Besides the frequent eruptions in the central Enclos Fouqué caldera, hundreds of eruptive vents opened along three main rift zones cutting the edifice during the last 50 kyrs. Two short rift zones are characterized by weak seismicity and lateral magma transport at shallow depth (above sea level). Here we focus on the third and largest rift zone (15km wide, 20 km long), which extends in a north-westerly direction between PdF and nearby Piton des Neiges volcanic complex. It is typified by deep seismicity (up to 30 km), emitting mostly primitive magmas, testifying of high fluid pressures (up to 5 kbar) and large-volume eruptions. We present new field data (including stratigraphic logs, a geological map of the area, C-14 dating and geochemical analyses of the eruption products) on one of the youngest (~6kyrs) and largest lava field (Trous Blancs eruption). It extends for 24km from a height of 1800 m asl, passing Le Tampon and Saint Pierre cities, until reaching the coast. The source area of this huge lava flow has been identified in an alignment of four previously unidentified pit craters. The eruption initiated with intense fountaining activity, producing a m-thick bed of loose black scoria, which becomes densely welded in its upper part; followed by an alternation of volume rich lava effusions and strombolian activity, resulting in the emplacement of meter-thick, massive units of olivine-basalt alternating with coarse scoria beds in the proximal area. Activity ended with the emplacement of a dm-thick bed of glassy, dense scoria and a stratified lithic

  6. Case of correlation between Rn anomalies and seismic activity on a volcano (Vulcano Island, Southern Tyrrhenian Sea)

    SciTech Connect

    Del Pezzo, E.; Gasparini, P.; Mantovani, M.S.M.; Martini, M.; Capaldi, G.; Gomes, Y.T.; Pece, R.

    1981-09-01

    A factor of 10 increase in the Rn concentration in a shallow aquifer forefunning a shallow seismic swarm was observed at the island of Vulcano (Aeolian island arc). The peak of Rn anomaly preceded by about one month the seismic swarm, which had a cumulative magnitude of 2.1. The time lag between the two phenomena is much longer than expected, given the small energy released by the swarm. The observed phenomena may not have a direct cause-effect relationship, but they both can be a consequence of volcanic phenomena.

  7. The evolution of ocean island volcanoes in a stationary plate environment and its implications concerning hotspot dynamics

    NASA Astrophysics Data System (ADS)

    Ramalho, R.

    2012-04-01

    The evolution of oceanic hotspot systems is strongly influenced by plate velocity relative to the melting source, age/thickness of the lithosphere, proximity to a plate boundary, and melting source parameters. In fast-moving plates, volcanic loci move away from the melting source and an obvious mechanism for the waning of volcanism is established. A linear island chain is thus created and a distinct edifice evolutionary pattern is recognizable. This evolutionary pattern is strongly influenced by long-term subsidence created by flexural loading and hotspot swell decay with plate movement, albeit some small uplift when edifices cross the flexural bulge; the transition from island to guyot is essentially dictated by subsidence. Conversely, in stationary or quasi-stationary plate environments, edifices do not or barely move away from the melting source so other mechanisms must be accounted for the long-term decrease in volcanic activity and the different edifice evolution. The Cape Verde Archipelago is the type-example of a hotspot in an old, stiff plate that is stationary with respect to its melting source, making it an ideal place to study ocean island evolution and oceanic hotspot dynamics in a stationary plate environment. Observations in this archipelago suggest that island evolution in such geodynamic environments is generally characterized by long-term vertical stability or even pronounced uplift trends, prolonging the islands lifetime above sea-level; the transition from island to guyot is essentially dictated by marine erosion. Uplift reconstructions for the Cape Verde Archipelago - using dateable relative sea-level tracers such as lava deltas, submarine volcanic units and marine terraces - suggest that two processes have acted to raise the islands during their lifetime. During an initial phase, mantle processes acted to build the swell. Subsequently, magmatic intrusions in the island edifice caused up to 350 m of local uplift at the scale of individual

  8. Microearthquake activity around Kueishantao island, offshore northeastern Taiwan: Insights into the volcano-tectonic interactions at the tip of the southern Okinawa Trough

    NASA Astrophysics Data System (ADS)

    Konstantinou, K. I.; Pan, C.-Y.; Lin, C.-H.

    2013-05-01

    Kueishantao is a volcanic island located offshore the northeastern coast of Taiwan and lies at the tip of the southern Okinawa Trough which is the back-arc basin of the Ryukyu subduction zone. Its last eruption occurred during the Holocene (~ 7 ka), hence Kueishantao can be considered as an active volcano. In an effort to better understand how magmatic processes may interact with the regional tectonics, a seismic network was installed in the area during early January 2008. This network consisted of 16 three-component seismometers located both on Kueishantao and the coast of northeastern Taiwan. One year of data was analyzed yielding 425 earthquakes whose P and S arrival times were manually picked and each event was located using a nonlinear probabilistic location method. In order to improve the location accuracy, the minimum 1-D velocity model for this dataset was derived and all earthquakes were relocated using this model. The results show a tight cluster of events near Kueishantao while the remaining earthquakes are scattered between the island and mainland Taiwan. The majority of hypocentral depths range between 2.5 and 10 km where the former depth coincides with the bottom of the shallow sedimentary layer and the latter with the ductile lower crust. Waveforms of the three largest events were also inverted for the determination of their deviatoric and full moment tensor. No statistically significant isotropic component was found, while two of the events can be explained by a double-couple source. The third event exhibited a low frequency content (< 10 Hz) and a large non-double-couple component suggesting fluid involvement at its source. A stress inversion of all available focal mechanisms in the area shows that fluid circulation in the upper crust generates a local stress field around Kueishantao facilitating the opening of cracks along the NW-SE direction of regional extension.

  9. Detection of microwave emission due to rock fracture as a new tool for geophysics: A field test at a volcano in Miyake Island, Japan

    NASA Astrophysics Data System (ADS)

    Takano, Tadashi; Maeda, Takashi; Miki, Yoji; Akatsuka, Sayo; Hattori, Katsumi; Nishihashi, Masahide; Kaida, Daishi; Hirano, Takuya

    2013-07-01

    This paper describes a field test to verify a newly discovered phenomenon of microwave emission due to rock fracture in a volcano. The field test was carried out on Miyake Island, 150 km south of Tokyo. The main objective of the test was to investigate the applicability of the phenomenon to the study of geophysics, volcanology, and seismology by extending observations of this phenomenological occurrence from the laboratory to the natural field. We installed measuring systems for 300 MHz, 2 GHz, and 18 GHz-bands on the mountain top and mountain foot in order to discriminate local events from regional and global events. The systems include deliberate data subsystems that store slowly sampled data in the long term, and fast sampled data when triggered. We successfully obtained data from January to February 2008. During this period, characteristic microwave pulses were intermittently detected at 300 MHz. Two photographs taken before and after this period revealed that a considerably large-scale collapse occurred on the crater cliff. Moreover, seismograms obtained by nearby observatories strongly suggest that the crater subsidence occurred simultaneously with microwave signals on the same day during the observation period. For confirmation of the microwave emission caused by rock fracture, these microwave signals must be clearly discriminated from noise, interferences, and other disturbances. We carefully discriminated the microwave data taken at the mountaintop and foot, checked the lightning strike data around the island, and consequently concluded that these microwave signals could not be attributed to lightning. Artificial interferences were discriminated by the nature of their waveforms. Thus, we inferred that the signals detected at 300 MHz were due to rock fractures during cliff collapses. This result may provide a useful new tool for geoscientists and for the mitigation of natural hazards.

  10. Great Balls of Fire: A probabilistic approach to quantify the hazard related to ballistics - A case study at La Fossa volcano, Vulcano Island, Italy

    NASA Astrophysics Data System (ADS)

    Biass, Sébastien; Falcone, Jean-Luc; Bonadonna, Costanza; Di Traglia, Federico; Pistolesi, Marco; Rosi, Mauro; Lestuzzi, Pierino

    2016-10-01

    We present a probabilistic approach to quantify the hazard posed by volcanic ballistic projectiles (VBP) and their potential impact on the built environment. A model named Great Balls of Fire (GBF) is introduced to describe ballistic trajectories of VBPs accounting for a variable drag coefficient and topography. It relies on input parameters easily identifiable in the field and is designed to model large numbers of VBPs stochastically. Associated functions come with the GBF code to post-process model outputs into a comprehensive probabilistic hazard assessment for VBP impacts. Outcomes include probability maps to exceed given thresholds of kinetic energies at impact, hazard curves and probabilistic isoenergy maps. Probabilities are calculated either on equally-sized pixels or zones of interest. The approach is calibrated, validated and applied to La Fossa volcano, Vulcano Island (Italy). We constructed a generic eruption scenario based on stratigraphic studies and numerical inversions of the 1888-1890 long-lasting Vulcanian cycle of La Fossa. Results suggest a ~ 10- 2% probability of occurrence of VBP impacts with kinetic energies ≤ 104 J at the touristic locality of Porto. In parallel, the vulnerability to roof perforation was estimated by combining field observations and published literature, allowing for a first estimate of the potential impact of VBPs during future Vulcanian eruptions. Results indicate a high physical vulnerability to the VBP hazard, and, consequently, half of the building stock having a ≥ 2.5 × 10- 3% probability of roof perforation.

  11. Precursory characteristics of the seismicity before the 6 August 2012 eruption of Tongariro volcano, North Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Hurst, Tony; Jolly, Arthur D.; Sherburn, Steven

    2014-10-01

    The 6 August 2012 eruption from the Upper Te Maari crater of Tongariro volcano followed approximately three weeks of precursory seismic activity. Earthquake relocations including data from extra temporary stations indicated that nearly all events were in a small area very close to Upper Te Maari. Most of these relocated events were very shallow, with nearly all events being between 1000 and 1500 m below the ground surface. The pre-eruption seismicity occurred in three main swarms. During the first swarm on 12-13 July 2012, all the earthquakes had consistent inter-event times of 71 ± 8 min, while in the later swarms (17-20 and 29-30 July) many events had a similar pattern of consistent inter-event times. The stationary quasi-periodic ("clockwork") earthquake process suggests that a single fracture point was excited by a nearly constant rate flux process. The dominant type of earthquake observed in these swarms had a sharp onset and a broad spectrum, with strong energy from 2 to 10 Hz. Most events seen had a local magnitude of 1.5 to 2.5, with virtually no smaller events. Most of these earthquakes appeared to belong to a main earthquake family whose characteristics included a strong spectral component at about 2 Hz and three bursts of energy spaced at intervals of about 1.5 s. Of the 116 located earthquakes, 75 had a correlation coefficient greater than 0.70 with a master event. The spectra of these events did not change with size, with matching frequency peaks for all the events with a high correlation. The last event of this type was the day before the 6 August 2012 eruption, none have been seen since and there has been very little seismicity under Tongariro. This seismicity alerted GNS Science and other organisations to the unrest of Tongariro, and the Volcanic Alert Level and Aviation Colour Code were raised to publicise this. GNS Science also increased its monitoring of Tongariro, and discovered that the magmatic gas concentrations had increased compared to

  12. Nicaraguan Volcanoes

    Atmospheric Science Data Center

    2013-04-18

    article title:  Nicaraguan Volcanoes     View Larger Image Nicaraguan volcanoes, February 26, 2000 . The true-color image at left is a ... February 26, 2000 - Plumes from the San Cristobal and Masaya volcanoes. project:  MISR category:  gallery ...

  13. Spacecraft Reed-Solomon downlink module

    NASA Technical Reports Server (NTRS)

    Luong, Huy H. (Inventor); Donaldson, James A. (Inventor); Wood, Steven H. (Inventor)

    1998-01-01

    Apparatus and method for providing downlink frames to be transmitted from a spacecraft to a ground station. Each downlink frame includes a synchronization pattern and a transfer frame. The apparatus may comprise a monolithic Reed-Solomon downlink (RSDL) encoding chip coupled to data buffers for storing transfer frames. The RSKL chip includes a timing device, a bus interface, a timing and control unit, a synchronization pattern unit, and a Reed-Solomon encoding unit, and a bus arbiter.

  14. Vertical Motions of Oceanic Volcanoes

    NASA Astrophysics Data System (ADS)

    Clague, D. A.; Moore, J. G.

    2006-12-01

    Oceanic volcanoes offer abundant evidence of changes in their elevations through time. Their large-scale motions begin with a period of rapid subsidence lasting hundreds of thousands of years caused by isostatic compensation of the added mass of the volcano on the ocean lithosphere. The response is within thousands of years and lasts as long as the active volcano keeps adding mass on the ocean floor. Downward flexure caused by volcanic loading creates troughs around the growing volcanoes that eventually fill with sediment. Seismic surveys show that the overall depression of the old ocean floor beneath Hawaiian volcanoes such as Mauna Loa is about 10 km. This gross subsidence means that the drowned shorelines only record a small part of the total subsidence the islands experienced. In Hawaii, this history is recorded by long-term tide-gauge data, the depth in drill holes of subaerial lava flows and soil horizons, former shorelines presently located below sea level. Offshore Hawaii, a series of at least 7 drowned reefs and terraces record subsidence of about 1325 m during the last half million years. Older sequences of drowned reefs and terraces define the early rapid phase of subsidence of Maui, Molokai, Lanai, Oahu, Kauai, and Niihau. Volcanic islands, such as Maui, tip down toward the next younger volcano as it begins rapid growth and subsidence. Such tipping results in drowned reefs on Haleakala as deep as 2400 m where they are tipped towards Hawaii. Flat-topped volcanoes on submarine rift zones also record this tipping towards the next younger volcano. This early rapid subsidence phase is followed by a period of slow subsidence lasting for millions of years caused by thermal contraction of the aging ocean lithosphere beneath the volcano. The well-known evolution along the Hawaiian chain from high to low volcanic island, to coral island, and to guyot is due to this process. This history of rapid and then slow subsidence is interrupted by a period of minor uplift

  15. Exploring SARAL/Altika data in the Solomon Sea

    NASA Astrophysics Data System (ADS)

    Djath, Bughsin; Ganachaud, Alexandre; Gourdeau, Lionel; Verron, Jacques

    2015-04-01

    In the South West Pacific, the Solomon Sea is a key region in the oceanic climate circuit that connects the equator to the subtropics through the LLWBCs (Low Latitude Western Boundary Currents). In their pathway toward the equator, their changes in strength or water masses properties could influence ENSO low-frequence modulation. Besides, it exhibits the highest variability of the southwest Pacific. Recent studies (Gourdeau et al., 2014; Hristina et al., 2014) have highlighted the specific eddy activity in this region: eddy generation/propagation and mechanism at the mesoscales. However, this region is poorly documented because of the lack of observation data. Only space observation and numerical model could give a synoptic monitoring of this region. Indeed, SARAL/Altika is providing improved high resolution data for studying mesoscale processes in the ocean. The goal of this study is to monitor mesoscale variability, the western boundary currents and pathways toward the equator. A dual approach, based both on SARAL/Altika along track data and high resolution modeling has then been chosen for these purpose. In this study, to analyze altimetric data, we use a specific median filter as the bathymetry of the Solomon Sea is complex (due to numerous islands and straits). The reprocessing data permits to eliminate erroneous data and provide a good quality dataset. It shows a high variability in the Solomon Sea. In order to explore SARAL/Altika temporal observability of mesoscale signal, a high resolution numerical model (1/36°) is used. The model is two-way embedded in a 1/12° regional model which is itself one-way embedded in the DRAKKAR 1/12° global model. The NEMO code is used as well as the AGRIF software for model nestings

  16. The Kolumbo submarine volcano of Santorini island is a large pool of bacterial strains with antimicrobial activity.

    PubMed

    Bourbouli, Maria; Katsifas, Efstathios A; Papathanassiou, Evangelos; Karagouni, Amalia D

    2015-05-01

    Microbes in hydrothermal vents with their unique secondary metabolism may represent an untapped potential source of new natural products. In this study, samples were collected from the hydrothermal field of Kolumbo submarine volcano in the Aegean Sea, in order to isolate bacteria with antimicrobial activity. Eight hundred and thirty-two aerobic heterotrophic bacteria were isolated and then differentiated through BOX-PCR analysis at the strain level into 230 genomic fingerprints, which were screened against 13 different type strains (pathogenic and nonpathogenic) of Gram-positive, Gram-negative bacteria and fungi. Forty-two out of 176 bioactive-producing genotypes (76 %) exhibited antimicrobial activity against at least four different type strains and were selected for 16S rDNA sequencing and screening for nonribosomal peptide (NRPS) and polyketide (PKS) synthases genes. The isolates were assigned to genus Bacillus and Proteobacteria, and 20 strains harbored either NRPS, PKS type I or both genes. This is the first report on the diversity of culturable mesophilic bacteria associated with antimicrobial activity from Kolumbo area; the extremely high proportion of antimicrobial-producing strains suggested that this unique environment may represent a potential reservoir of novel bioactive compounds.

  17. Flank instability of Stromboli volcano (Aeolian Islands, Southern Italy): Integration of GB-InSAR and geomorphological observations

    NASA Astrophysics Data System (ADS)

    Intrieri, Emanuele; Di Traglia, Federico; Del Ventisette, Chiara; Gigli, Giovanni; Mugnai, Francesco; Luzi, Guido; Casagli, Nicola

    2013-11-01

    Stromboli is characterized by frequent explosions of variable energy and periodically interrupted by more energetic blasts emitting large volumes of material. The pressurization of a volatile-poor, high-porphyritic magma column that is gas-recharged by the deep-seated, volatile-rich, low-porphyritic magma precedes such events and produces deformations on the NW flank of the volcano, Sciara del Fuoco. By integrating geomorphological observations with long-term displacements from ground-based interferometric radar since December 2007, we identified two landslides whose movements are strongly related with volcanic activity. Movement patterns obtained through a novel long-term analysis of GB-InSAR data permitted us to hypothesize the type of movement and depth for both landslides. Furthermore their position allowed us to affirm that the effusive vent formed in 2007 at 400 m a.s.l., was the result of the deflection of a feeder dike caused by landslide fractures, thus showing the important role of geomorphological discontinuities in volcanic environments.

  18. Groundwater salinity and hydrochemical processes in the volcano-sedimentary aquifer of La Aldea, Gran Canaria, Canary Islands, Spain.

    PubMed

    Cruz-Fuentes, Tatiana; Cabrera, María del Carmen; Heredia, Javier; Custodio, Emilio

    2014-06-15

    The origin of the groundwater salinity and hydrochemical conditions of a 44km(2) volcano-sedimentary aquifer in the semi-arid to arid La Aldea Valley (western Gran Canaria, Spain) has been studied, using major physical and chemical components. Current aquifer recharge is mainly the result of irrigation return flows and secondarily that of rainfall infiltration. Graphical, multivariate statistical and modeling tools have been applied in order to improve the hydrogeological conceptual model and identify the natural and anthropogenic factors controlling groundwater salinity. Groundwater ranges from Na-Cl-HCO3 type for moderate salinity water to Na-Mg-Cl-SO4 type for high salinity water. This is mainly the result of atmospheric airborne salt deposition; silicate weathering, and recharge incorporating irrigation return flows. High evapotranspiration produces significant evapo-concentration leading to relative high groundwater salinity in the area. Under average conditions, about 70% of the water used for intensive agricultural exploitation in the valley comes from three low salinity water runoff storage reservoirs upstream, out of the area, while the remaining 30% derives from groundwater. The main alluvial aquifer behaves as a short turnover time reservoir that adds to the surface waters to complement irrigation water supply in dry periods, when it reaches 70% of irrigation water requirements. The high seasonality and intra-annual variability of water demand for irrigation press on decision making on aquifer use by a large number of aquifer users acting on their own.

  19. Groundwater salinity and hydrochemical processes in the volcano-sedimentary aquifer of La Aldea, Gran Canaria, Canary Islands, Spain.

    PubMed

    Cruz-Fuentes, Tatiana; Cabrera, María del Carmen; Heredia, Javier; Custodio, Emilio

    2014-06-15

    The origin of the groundwater salinity and hydrochemical conditions of a 44km(2) volcano-sedimentary aquifer in the semi-arid to arid La Aldea Valley (western Gran Canaria, Spain) has been studied, using major physical and chemical components. Current aquifer recharge is mainly the result of irrigation return flows and secondarily that of rainfall infiltration. Graphical, multivariate statistical and modeling tools have been applied in order to improve the hydrogeological conceptual model and identify the natural and anthropogenic factors controlling groundwater salinity. Groundwater ranges from Na-Cl-HCO3 type for moderate salinity water to Na-Mg-Cl-SO4 type for high salinity water. This is mainly the result of atmospheric airborne salt deposition; silicate weathering, and recharge incorporating irrigation return flows. High evapotranspiration produces significant evapo-concentration leading to relative high groundwater salinity in the area. Under average conditions, about 70% of the water used for intensive agricultural exploitation in the valley comes from three low salinity water runoff storage reservoirs upstream, out of the area, while the remaining 30% derives from groundwater. The main alluvial aquifer behaves as a short turnover time reservoir that adds to the surface waters to complement irrigation water supply in dry periods, when it reaches 70% of irrigation water requirements. The high seasonality and intra-annual variability of water demand for irrigation press on decision making on aquifer use by a large number of aquifer users acting on their own. PMID:24698802

  20. The Kolumbo submarine volcano of Santorini island is a large pool of bacterial strains with antimicrobial activity.

    PubMed

    Bourbouli, Maria; Katsifas, Efstathios A; Papathanassiou, Evangelos; Karagouni, Amalia D

    2015-05-01

    Microbes in hydrothermal vents with their unique secondary metabolism may represent an untapped potential source of new natural products. In this study, samples were collected from the hydrothermal field of Kolumbo submarine volcano in the Aegean Sea, in order to isolate bacteria with antimicrobial activity. Eight hundred and thirty-two aerobic heterotrophic bacteria were isolated and then differentiated through BOX-PCR analysis at the strain level into 230 genomic fingerprints, which were screened against 13 different type strains (pathogenic and nonpathogenic) of Gram-positive, Gram-negative bacteria and fungi. Forty-two out of 176 bioactive-producing genotypes (76 %) exhibited antimicrobial activity against at least four different type strains and were selected for 16S rDNA sequencing and screening for nonribosomal peptide (NRPS) and polyketide (PKS) synthases genes. The isolates were assigned to genus Bacillus and Proteobacteria, and 20 strains harbored either NRPS, PKS type I or both genes. This is the first report on the diversity of culturable mesophilic bacteria associated with antimicrobial activity from Kolumbo area; the extremely high proportion of antimicrobial-producing strains suggested that this unique environment may represent a potential reservoir of novel bioactive compounds. PMID:25627249

  1. Investigation of the Volcano-tectonic dynamics of Vulcano Island by long-term (40 years) geophysical data

    NASA Astrophysics Data System (ADS)

    Bonforte, Alessandro; Alparone, Salvatore; Gambino, Salvatore; Guglielmino, Francesco; Obrizzo, Francesco; Velardita, Rosanna

    2015-04-01

    Vulcano island is a composite volcanic edifice located in the south-central sector of the Aeolian Archipelago (Tyrrhenian Sea, Italy). It is the southernmost tip of the southern branch of the Y-shaped archipelago; in particular, it is part of the bigger Lipari-Vulcano volcanic complex that comprises the two southernmost islands of the archipelago. This branch of the archipelago is NNW-SSE oriented and represent the off-shore prolongation of the Tindari-Letojanni tectonic lineament in the NE Sicily, splitting the Appennine chain on the west, from the Calabrian arc on the East. N-S compression seems to affect the western side of this NNW-SSE lineament, while extension affects the eastern one, with active volcanism and a NW dipping Benioff plane. Historic activity at Vulcano has been characterized by frequent transitions from phereatomagmatic to minor magmatic activity. The last eruption in 1888-90 was characterized by energetic explosive pulses and defines the so-called "vulcanian" type of activity. Since then, volcanic activity has taken the form of fumarolic emanations of variable intensity and temperature, mainly concentrated at "La Fossa" crater, with maximum temperatures ranging between 200° and 300° C; temperature increases and changes in the gas chemistry, were often observed. The most recent episode began in the 80's when fumarole temperature progressively increased to 690°C in May 1993. Vulcano is active and this favoured monitoring and research studies, in particular focussed on the most recent structures. In the frame of DPC-INGV "V3" project, we investigate the dynamics of the island through ca. 40 years of ground deformation and seismicity data collected by the discrete and continuous INGV monitoring networks. We considered levelling, GPS, EDM, seismic and tilt data. EDM and levelling measurements began in the middle 1970s and since the late 1990s the same EDM network has been surveyed by GPS. By combining and comparing geodetic data and seismicity we

  2. Erupting Volcano Mount Etna

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Expedition Five crew members aboard the International Space Station (ISS) captured this overhead look at the smoke and ash regurgitated from the erupting volcano Mt. Etna on the island of Sicily, Italy in October 2002. Triggered by a series of earthquakes on October 27, 2002, this eruption was one of Etna's most vigorous in years. This image shows the ash plume curving out toward the horizon. The lighter-colored plumes down slope and north of the summit seen in this frame are produced by forest fires set by flowing lava. At an elevation of 10,990 feet (3,350 m), the summit of the Mt. Etna volcano, one of the most active and most studied volcanoes in the world, has been active for a half-million years and has erupted hundreds of times in recorded history.

  3. Origin of anorthite and olivine megacrysts in island-arc tholeiites: petrological study of 1940 and 1962 ejecta from Miyake-jima volcano, Izu-Mariana arc

    NASA Astrophysics Data System (ADS)

    Amma-Miyasaka, Mizuho; Nakagawa, Mitsuhiro

    2002-10-01

    Although aphyric tholeiites were discharged from nearly the same fissures during 1940 and 1962 eruptions of Miyake-jima volcano, some of the 1940 rocks are characterized by the presence of anorthite (to 3 cm) and olivine (to 4 mm) megacrysts. We focus on the assemblage and composition of crystal-clots to discuss magmatic processes, because minerals in the same type of clots must have crystallized at the same time. Three types of clots are identified, megacryst (M), basaltic (B; 1190-1175°C) and andesitic (A; 1150-1080°C). The M-type crystal-clots are characterized by anorthite (An 87-96) and olivine (Fo 78-86) megacrysts. Major mafic minerals of the B-type and A-type crystal-clots are olivine-clinopyroxene without magnetite, and pyroxenes with magnetite, respectively. The 1940 megacryst-bearing rocks contain all the three types of clots, whereas 1940 megacryst-free rocks contain only A-type and B-type. However, megacrysts and M-type clots show petrographic features such as kink-bands of olivine, spherical olivines in anorthite, and wide homogeneous cores of anorthite, suggesting that these minerals may not be comagmatic phenocrysts but xenocrysts. Chemical compositions and crystal size distribution plots of these crystals are identical to those of plutonic xenoliths erupted from one of the 1940 fissure. Thus, we concluded that megacrysts and M-type clots are xenocrysts derived from the same sources as plutonic xenoliths. We consider that the magma plumbing system of the 1940 eruption consists of a deeper basaltic magma storage system and a shallower andesitic one. The plutonic body might be located under the northeastern part of the volcano between two magma storage systems. The basaltic magma captured plutonic xenoliths, and then mixed with the andesitic magma during the 1940 eruption. Whether erupted rocks contain xenocrysts or not must depend on the spatial relationship between ascending basaltic dykes and location of the deep-seated plutonic body. On the

  4. Geochemical characteristics of the "Mid-Alkaline Basalts" from the "adventive cones" of Piton de la Fournaise volcano (La Réunion Island)

    NASA Astrophysics Data System (ADS)

    Valer, Marina; Bachèlery, Patrick; Schiano, Pierre; Upton, Brian G. J.

    2016-04-01

    Piton de la Fournaise, the youngest volcano of La Réunion Island, is renowned for being frequently active. Its lavas (younger than ~450 ka) have been subdivided into three compositional groups (see Lénat et al. 2012 for a review). Almost all recent and historical lavas belong to two of these groups: "cotectic basalts" and "olivine-rich basalts", marked by a constant CaO/Al2O3 ratio of ~0.8, and MgO content ranging from 5 to 30 wt % reflecting different degrees of olivine accumulation. Whereas that current activity is mainly located within the "Enclos Fouqué" caldera, ~100 strombolian cones lie on the volcano's flanks, thought to date from ~300 years to a few thousand years. Our study focuses on these "adventive cones", by studying bulk-rock major and trace element compositions, isotopic compositions, mineral phases and olivine-hosted melt inclusions. The bulk-rock compositions correspond to the third group of the Piton de la Fournaise lavas (see above), called the "mid-alkaline basalts". They mainly consist of magnesian basalts at 7.55 - 10.24 wt% MgO and CaO/Al2O3 values down to 0.55. At constant MgO content, this group shows higher alkali content and a relative deficiency in Ca compared to the historic basalts. The "adventive cones" lavas usually contain magnesian olivine crystals (Fo > 86). Such crystals are not at the equilibrium with their host lava, raising thus the question of the recycling processes. The volatile contents of these olivine-hosted melt inclusions (work in progress) will allow to determine if such magnesian olivine crystals come from deep storage levels, as previously proposed by Bureau et al. (1998; 1999). The specific geochemistry the "adventive cones" lavas is attributed either to a high-pressure fractionation of a clinopyroxene-rich assemblage (Albarède et al. 1997), or to an assimilation process involving wehrlite-gabbro cumulates (e.g. Salaün et al. 2010). Although the trace element data show that the source of these magmas is

  5. Quantitative analysis of seismic wave propagation anomalies in azimuth and apparent slowness at Deception Island volcano (Antarctica) using seismic arrays

    NASA Astrophysics Data System (ADS)

    Yeguas, A. García.; Almendros, J.; Abella, R.; Ibáñez, J. M.

    2011-02-01

    We analyse shot data recorded by eight seismic arrays during an active-source seismic experiment carried out at Deception Island (Antarctica) in 2005 January. For each source we estimate the apparent slowness and propagation azimuth of the first wave arrival. Since both source and receiver positions are accurately known, we are able to interpret the results in terms of the effect of the heterogeneities of the medium on wave propagation. The results show the presence of significant propagation anomalies. Nearby shots produce large apparent slowness values above 0.6 s km-1, while distant shots produce small values, down to about 0.15-0.20 s km-1. These values are different for each array, which shows the importance of the local structure under the receiver. The spatial distributions of apparent slowness are not radial as we would expect in a flat-layered medium. And again, these distributions are different for each array. The azimuth anomalies defined as the difference between the empirical estimates and the values expected in a 1-D model (i.e. the source-array directions) suggest ubiquitous wave front distortions. We have detected both positive and negative anomalies. For some shot-array geometries, azimuth anomalies are quite large with values up to 60°. The distribution of the anomalies depends on the position of the array. Some of these features can be interpreted in terms of a shallow magma chamber and shallow rigid bodies imaged by high-resolution seismic tomography. However several details remain unexplained. Further work is required, including modelling of synthetic wavefields on realistic models of Deception Island and/or apparent slowness vector tomography.

  6. Under the volcano: phylogeography and evolution of the cave-dwelling Palmorchestia hypogaea (Amphipoda, Crustacea) at La Palma (Canary Islands)

    PubMed Central

    Villacorta, Carlos; Jaume, Damià; Oromí, Pedro; Juan, Carlos

    2008-01-01

    Background The amphipod crustacean Palmorchestia hypogaea occurs only in La Palma (Canary Islands) and is one of the few terrestrial amphipods in the world that have adapted to a strictly troglobitic life in volcanic cave habitats. A surface-dwelling closely related species (Palmorchestia epigaea) lives in the humid laurel forest on the same island. Previous studies have suggested that an ancestral littoral Orchestia species colonized the humid forests of La Palma and that subsequent drought episodes in the Canaries reduced the distribution of P. epigaea favouring the colonization of lava tubes through an adaptive shift. This was followed by dispersal via the hypogean crevicular system. Results P. hypogaea and P. epigaea did not form reciprocally monophyletic mitochondrial DNA clades. They showed geographically highly structured and genetically divergent populations with current gene flow limited to geographically close surface locations. Coalescence times using Bayesian estima