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1

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

Microsoft Academic Search

Savo, Solomon Islands, is a historically active volcano dominated by sodic, alkaline lavas, and pyroclastic rocks with up\\u000a to 7.5 wt% Na2O, and high Sr, arc-like trace element chemistry. The suite is dominated by mugearites (plagioclase–clinopyroxene–magnetite ± amphibole ± olivine)\\u000a and trachytes (plagioclase–amphibole–magnetite ± biotite). The presence of hydrous minerals (amphibole, biotite) indicates\\u000a relatively wet magmas. In such melts, plagioclase is relatively unstable relative to iron oxides

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

2009-01-01

2

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

NASA Astrophysics Data System (ADS)

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.

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

3

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

NASA Astrophysics Data System (ADS)

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, ?Nd and ?Hf values in the analysed rocks range from 0.7035 to 0.7040, +6.4 to +7.9 and +12 to +14.4, respectively. These values reveal the presence of the Indian-Australian mantle domain beneath Simbo (i.e. the Indian-Australian plate) and also beneath all other volcanic islands of the New Georgia group, which are located north of the San Cristobál trench. 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb values (18.43-18.52, 15.49-15.55 and 18.13-18.34, respectively) confirm the presence of slab melts from the subducted Pacific plate beneath southern Simbo where the highest Gd(N)/Yb(N) ratios are reported. A spatial shift towards an Indian-Australian slab signature is observed when approaching the active San Cristobál trench on northern Simbo, reflecting the decreasing influence of slab melts from the old subducted Pacific plate.

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

2007-01-01

4

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

Microsoft Academic Search

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

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

2007-01-01

5

Ciguatera fish poisoning in the Solomon Islands.  

PubMed

Ciguatera fish poisoning may have existed in the Solomon Islands long ago though there has never been any ciguatera fish poisoning tests been carried to confirm its presence. Suspected occurrences are infrequent and seasonal. Most cases of ciguatera fish poisoning are undocumented that when cases do occur they depend largely on traditional-knowledge and anecdotal information. Areas suspected to have ciguatoxic poisoning problem in the Solomon Islands includes Santa Cruz, Rennell and Bellona, Indispensable reefs, Ontong Java and Wagina island. Fish species considered ciguatoxic includes red emperor, red snapper, roundfaced batfish, barracuda and blue lined sea-bream. In any way ciguatera fish poisoning is as yet not a big health problem in the Solomon Islands. PMID:1340336

Oreihaka, E

1992-01-01

6

The Solomon Islands Project: an introduction.  

PubMed

The twin themes of the Solomon Islands Biomedical Project remain 1) the remarkable genetic heterogeneity of the groups in the Solomons; and 2) the differential responses to these groups to rapid modernization/acculturation over the past two decades of this long term study. This introduction summarizes the historical and ethnic relationships of the survey groups, their established genetic distances and their rankings with regard to acculturation at the times of their first survey, and changes occurring up to 1985-86. Relevant features of diet, life style, and epidemiology are described. PMID:2333935

Friedlaender, J S

1990-04-01

7

Facial scarification and tattooing on Santa Catalina Island (Solomon Islands).  

PubMed

Ritual scarification is the culturally sanctioned process of incising the skin to achieve patterned scars. Scarification was practiced widely by traditional societies, but the encroachment of Western cultural expectations has made the practice increasingly uncommon. Ritual tattooing has a meaningful place in many traditional societies. Ritual scarification and tattooing are still found on Santa Catalina Island, an isolated member of the Solomon Islands in the south-west Pacific. PMID:9347234

Mammen, L; Norton, S A

1997-10-01

8

Paradoxes of postcolonial police-building: Solomon Islands  

Microsoft Academic Search

Drawing upon recent fieldwork, we examine the paradoxical effects of the institutional transfer and capacity-building approach adopted by the ongoing regional intervention in post-conflict Solomon Islands. Taking the mission's substantial police-building component as our focus, we argue that this engagement has done little to extend the functional authority of the local police in rural Solomon Islands and has, moreover, induced

Sinclair Dinnen; Matthew Allen

2012-01-01

9

A survey of village poultry production in the Solomon Islands  

Microsoft Academic Search

A total of 84 farmers in 31 villages of Guadalcanal, Western, Malaita and Central Provinces of the Solomon Islands were surveyed\\u000a to obtain baseline information on the current feeding practices and farmer attitudes to village poultry production. Farming\\u000a of village chickens in the Solomon Islands is conducted on a small scale. Most surveyed farmers thought chickens were easy\\u000a to care

T. Jansen; P. C. Glatz; Z. H. Miao

2009-01-01

10

Reunion Island Volcano Erupts  

NASA Technical Reports Server (NTRS)

On January 16, 2002, lava that had begun flowing on January 5 from the Piton de la Fournaise volcano on the French island of Reunion abruptly decreased, marking the end of the volcano's most recent eruption. These false color MODIS images of Reunion, located off the southeastern coast of Madagascar in the Indian Ocean, were captured on the last day of the eruption (top) and two days later (bottom). The volcano itself is located on the southeast side of the island and is dark brown compared to the surrounding green vegetation. Beneath clouds (light blue) and smoke, MODIS detected the hot lava pouring down the volcano's flanks into the Indian Ocean. The heat, detected by MODIS at 2.1 um, has been colored red in the January 16 image, and is absent from the lower image, taken two days later on January 18, suggesting the lava had cooled considerably even in that short time. Earthquake activity on the northeast flank continued even after the eruption had stopped, but by January 21 had dropped to a sufficiently low enough level that the 24-hour surveillance by the local observatory was suspended. Reunion is essentially all volcano, with the northwest portion of the island built on the remains of an extinct volcano, and the southeast half built on the basaltic shield of 8,630-foot Piton de la Fournaise. A basaltic shield volcano is one with a broad, gentle slope built by the eruption of fluid basalt lava. Basalt lava flows easily across the ground remaining hot and fluid for long distances, and so they often result in enormous, low-angle cones. The Piton de la Fournaise is one of Earth's most active volcanoes, erupting over 150 times in the last few hundred years, and it has been the subject of NASA research because of its likeness to the volcanoes of Mars. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

2002-01-01

11

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

Federal Register 2010, 2011, 2012, 2013

...the safety of life on navigable waters during a fireworks display launched from discharge barge located in Solomons Island, Calvert County, Maryland. This safety zone is intended to protect the maritime public in a portion of Solomons Island Harbor....

2010-04-09

12

The eruptive history and volcanic hazards of Savo, Solomon Islands  

Microsoft Academic Search

Savo Island is the 6-km-diameter emergent summit of an andesitic-dacitic stratovolcano, rising from the Iron Bottom Sound, 35 km NW of Honiara, Solomon Islands. Savo has erupted at least three times within recorded history and the 3,000 inhabitants maintain extensive oral traditions of past events. Through description and interpretation of the volcaniclastic sequences on the island, in conjunction with historical

M. Petterson; S. Cronin; P. Taylor; D. Tolia; A. Papabatu; T. Toba; C. Qopoto

2003-01-01

13

Haemophilus ducreyi Associated with Skin Ulcers among Children, Solomon Islands  

PubMed Central

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

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

2014-01-01

14

Aid for Education in Post-Conflict Solomon Islands  

ERIC Educational Resources Information Center

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…

Whalan, Jeni

2011-01-01

15

Scientific concept development in Solomon Island students: a comparative analysis  

Microsoft Academic Search

This paper summarises the results of an investigation of Solomon Islands secondary school students’ interpretations of three concepts: vision, animals and burning. Internal comparisons among the three areas and external comparisons with findings reported from other societies are made. While some support is given to the idea that children from different cultures may develop similar conceptions, this support is qualified

John Lowe

1997-01-01

16

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

PubMed

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

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

2010-10-01

17

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

ERIC Educational Resources Information Center

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…

Maebuta, Jack

2011-01-01

18

PREVALENCE OF ANTIBODY TO CHLAMYDIA PNEUMONIAE IN RESIDENTS OF JAPAN, THE SOLOMON ISLANDS, AND NEPAL  

Microsoft Academic Search

Sera of 4,050 residents from Japan, 276 from the Solomon Islands, and 602 from Nepal were tested by an enzyme-linked immunosorbent assay to determine the prevalence of antibody to Chlamydia pneumoniae. The preva- lence of IgG and IgA antibodies was significantly higher in the Solomon Islands (64.9% and 82.2%) and Nepal (73.1%, and 69.8%) than in Japan (53.6% and 41.1%).

CHIE SHIMIZU; SHIGEKI NABESHIMA; KENSUKE KIKUCHI; NORIHIRO FURUSYO; SEIZABURO KASHIWAGI; JUN HAYASHI

2002-01-01

19

The eruptive history and volcanic hazards of Savo, Solomon Islands  

NASA Astrophysics Data System (ADS)

Savo Island is the 6-km-diameter emergent summit of an andesitic-dacitic stratovolcano, rising from the Iron Bottom Sound, 35 km NW of Honiara, Solomon Islands. Savo has erupted at least three times within recorded history and the 3,000 inhabitants maintain extensive oral traditions of past events. Through description and interpretation of the volcaniclastic sequences on the island, in conjunction with historical accounts and oral traditions, we reconstruct the eruptive processes on Savo. Block-and-ash flow (BAF) deposits are volumetrically dominant on the island within three main depositional environments: near-vent sequences, thick medial channel sequences and distal fan sequences. The deposits comprise universally non-vesicular and highly porphyritic (40-70% phenocrysts), high-silica andesite and dacite clasts. These appear to have been derived from collapsing lava domes during an 1560-1570 A.D. eruption. However, eyewitness descriptions and crater morphology suggest that similar deposits formed from dome explosions or collapses of eruption columns during later eruptions (1830-1840 A.D.). The high-sodium magmas (ca. 5-7 wt% Na2O) apparently crystallised and strongly degassed prior to eruption. Shallow explosions were possibly caused by entrapment of magmatic gases beneath a dome or conduit plug of highly crystalline, near solid magma. Repeated sealing of the vent may have been due to inward collapse of the highly altered rocks of the surrounding hydrothermal system; these rocks probably were saturated due to contemporaneous high intensity rainfall events. BAFs were hot enough to char vegetation and attain aligned clast TRM (thermal remnant magnetism) up to 3 km from the vent, many being accompanied by ash-cloud surges. Changes with distance in the BAF deposits appear mostly dependent on flow confinement and are limited to an overall decrease in thickness and maximum clast size, and an increased definition of weak planar fabrics. In distal fan sequences, there is strong evidence for syn- and post-eruptive redeposition of primary deposits. Since the Savo population is concentrated on coastal volcaniclastic fans, we consider the greatest volcanic risk to life is from BAFs, associated ash-cloud surges and lahars. Hence, the main channels and fans are designated as the highest of three relative hazard zones on a simple map prepared to aid local education and planning initiatives on Savo.

Petterson, M. G.; Cronin, S. J.; Taylor, P. W.; Tolia, D.; Papabatu, A.; Toba, T.; Qopoto, C.

2002-11-01

20

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

ERIC Educational Resources Information Center

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…

Huebner, Thom, Comp.

21

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

ERIC Educational Resources Information Center

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…

de Guzman, Sylvia

2007-01-01

22

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

ERIC Educational Resources Information Center

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,…

Burton, Lindsay J.

2012-01-01

23

Field setting, mineralogy, chemistry, and genesis of arc picrites, New Georgia, Solomon Islands  

Microsoft Academic Search

The field setting, petrography, mineralogy, and geochemistry of a suite of picrite basalts and related magnesian olivine tholeiites (New Georgia arc picrites) from the New Georgia Volcanics, Kolo caldera in the active ensimatic Solomon Islands arc are presented. These lavas, with an areal extent in the order of 1002 km and almost 1 km thick in places, are located close

W. R. H. Ramsay; A. J. Crawford; J. D. Foden

1984-01-01

24

Prevalence of antibody to Chlamydia pneumoniae in residents of Japan, the Solomon Islands, and Nepal.  

PubMed

Sera of 4,050 residents from Japan, 276 from the Solomon Islands, and 602 from Nepal were tested by an enzyme-linked immunosorbent assay to determine the prevalence of antibody to Chlamydia pneumoniae. The prevalence of IgG and IgA antibodies was significantly higher in the Solomon Islands (64.9% and 82.2%) and Nepal (73.1%, and 69.8%) than in Japan (53.6% and 41.1%). These prevalence rates increased throughout the teenage years in the Solomon Islands and Japan and leveled off with age, whereas in Nepal the prevalence rates gradually increased with age. The prevalence of a high (> 3.0) IgA antibody index, which is suggestive of acute infection, was significantly higher in the Solomon Islands (34.8%) than in Japan (3.2%) and Nepal (10.5%). The prevalence of IgG antibody ranged from 46.4% to 67.7%, and the prevalence of IgA antibody ranged from 33.7% to 61.8% in the four difference areas of Japan. These findings indicate considerable differences in the prevalence of antibodies to C. pneumoniae by age in these nations and between the regions of Japan tested. PMID:12389943

Shimizu, Chie; Nabeshima, Shigeki; Kikuchi, Kensuke; Furusyo, Norihiro; Kashiwagi, Seizaburo; Hayashi, Jun

2002-08-01

25

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

SciTech Connect

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.

Hirono, A.; Ishii, A.; Hirono, K.; Miwa, S. [National Institute of Health, Tokyo (Japan); Kere, N. [Medical Research and Training Institute, Honiara (Japan); Fujii, H. [Tokyo Women`s Medical College, Tokyo (Japan)

1995-05-01

26

Kanaga Volcano, Aleutian Islands, Alaska  

NSDL National Science Digital Library

These images of the Kanaga Volcano show the symmetrical cone which is characteristic of stratovolcanoes. It is also possible to see how the current volcanic edifice has grown inside an older caldera, the remains of ancient Mount Kanaton. References and links to related sites are included.

27

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

PubMed Central

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

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

2013-01-01

28

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

NASA Astrophysics Data System (ADS)

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 waves hit. In the Solomons, there was less than 3 minutes separation time, and the populations with indigenous knowledge were able to save themselves. Mitigation strategies for those that live adjacent to tsunamigenic subduction zones must include a community-based disaster management plan to educate a variety of populations with different cultural knowledges. This education can be in concert with development of an basin-wide early warning system.

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

2007-12-01

29

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

PubMed Central

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

2012-01-01

30

Health impacts of climate change in the solomon islands: an assessment and adaptation action plan.  

PubMed

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

Spickett, Jeffery T; Katscherian, Dianne

2014-09-01

31

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

NASA Astrophysics Data System (ADS)

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.

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

2007-12-01

32

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

33

Patterns of adult weight and fat change in six Solomon Islands societies: A semi-longitudinal study  

Microsoft Academic Search

Semi-longitudinal changes with aging in weight, height, arm circumference, and subscapular and triceps skinfold circumference are presented for adult males and females in 6 different populations in the Solomon Islands and Papua New Guinea, which have differed dramatically in their exposure to modern industrialized societies over the past decade. Those groups who remain less acculturated show little or no evidence

Jonathan S. Friedlaender; John G. Rhoads

1982-01-01

34

Malaria control in central Malaita, Solomon Islands 2. Local perceptions of the disease and practices for its treatment and prevention  

Microsoft Academic Search

Government health policy for malaria control in Solomon Islands has three main objectives: (1) early diagnosis and treatment of malaria at a health service; (2) reduction of human-vector contact through widespread use of insecticide-impregnated bed nets; and (3) provision of malaria chemoprophylaxis for pregnant women. Social research was carried out in thirteen villages in central Malaita to determine local attitudes

Joel M. Dulhunty; Keflemariam Yohannes; Chaibai Kourleoutov; Vaipulu T. Manuopangai; Morris K. Polyn; William J. Parks; Joan H. Bryan

2000-01-01

35

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

NASA Astrophysics Data System (ADS)

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.

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

2008-03-01

36

Implications of urbanization for artisanal parrotfish fisheries in the Western Solomon Islands.  

PubMed

Increasing migration into urbanized centers in the Solomon Islands poses a great threat to adjacent coral reef fisheries because of negative effects on the fisheries and because it further erodes customary management systems. Parrotfish fisheries are of particular importance because the feeding habits of parrotfish (scrape and excavate coral) are thought to be critical to the resilience of coral reefs and to maintaining coral reef health within marine protected areas. We investigated the ecological impact of localized subsistence and artisanal fishing pressure on parrotfish fisheries in Gizo Town, Western Solomon Islands, by analyzing the density and size distribution of parrotfish with an underwater visual census (UVC), recall diary (i.e., interviews with fishers), and creel surveys to independently assess changes in abundance and catch-per-unit-effort (CPUE) over 2 years. We then compared parrotfish data from Gizo Town with equivalent data from sites open to and closed to fishing in Kida and Nusa Hope villages, which have different customary management regimes. Results indicated a gradient of customary management effectiveness. Parrotfish abundance was greater in customary management areas closed to fishing, especially with regard to larger fish sizes, than in areas open to fishing. The decline in parrotfish abundance from 2004 to 2005 in Gizo was roughly the same magnitude as the difference in abundance decline between inside and outside customary management marine reserves. Our results highlight how weak forms of customary management can result in the rapid decline of vulnerable fisheries around urbanized regions, and we present examples in which working customary management systems (Kinda and Nusa Hope) can positively affect the conservation of parrotfish--and reef fisheries in general--in the highly biodiverse Coral Triangle region. PMID:19961509

Aswani, Shankar; Sabetian, Armagan

2010-04-01

37

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

PubMed Central

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

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

2014-01-01

38

Bathymetric constraints on the tectonic and volcanic evolution of Deception Island Volcano, South Shetland Islands  

E-print Network

Bathymetric constraints on the tectonic and volcanic evolution of Deception Island Volcano, South Shetland Islands A.H. BARCLAY1 *, W.S.D. WILCOCK2 and J.M. IBA´ N~ EZ3 1 Lamont-Doherty Earth Observatory@ldeo.columbia.edu Abstract: Deception Island is the largest volcano in the actively extending Bransfield Basin, a marginal

Wilcock, William

39

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

PubMed Central

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

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

2014-01-01

40

Hospital visits due to domestic violence from 1994 to 2011 in the solomon islands: a descriptive case series.  

PubMed

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

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

2014-09-01

41

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

E-print Network

island-arc volcano Jennifer A. Wadea,T, Terry Planka , Robert J. Sternb , Darren L. Tollstrupc , James B, USA b Geosciences Department, University of Texas at Dallas, Richardson, TX 75083, USA c Department

Stern, Robert J.

42

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

PubMed Central

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

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

43

Living on Active Volcanoes - The Island of Hawaii  

NSDL National Science Digital Library

This United States Geological Survey (USGS) on-line publication highlights the volcanic hazards facing the people living on the Island of Hawaii. These hazards include lava flows, explosive eruptions, volcanic smog, earthquakes and tsunamis. This report discusses these hazards, the volcanoes of Mauna Loa and Kilauea, and the work of the Hawaiian Volcano Observatory to monitor and issue warnings to the people affected by these hazards.

Heliker, Christina; Stauffer, Peter; Hendley Ii., James

44

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

PubMed Central

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. (?SC = 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 (?CT = 0.863, P < 0.01; ?ST = 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

2008-01-01

45

A preliminary seismic study of Taal Volcano, Luzon Island Philippines  

NASA Astrophysics Data System (ADS)

The very active Taal Volcano lies in the southern part of Luzon Island only 60 km from Manila, the capital of the Philippines. In March 2008 we deployed a temporary seismic network around Taal that consisted of 8 three-component short period seismometers. This network recorded during the period from March to November 2008 about 1050 local events. In the early data processing stages, unexpected linear drifting of clock time was clearly identified for a number of stations. The drifting rates of each problematic station were determined and the errors were corrected before further processing. Initial location of each event was derived by manually picked P-/S-phases arrival times using HYPO71 and a general velocity model based on AK135. Since the velocity structure beneath Taal is essentially unknown, we used travel times of 338 well-located events in order to derive a minimum 1D velocity model using VELEST. The resulting locations show that most events occurred at the shallow depth beneath the Taal Volcano, and two major earthquake groups were noticed, with one lying underneath the western shore of Taal lake and the other one spread around the eastern flank of the Taal Volcano. Since there is no reported volcano activities during the operation period of our seismic array, we are still not confident to interpret these findings in terms of other natures of volcano at the current stage. However, our work represents an important pioneer step towards other more advanced seismic studies in Taal Volcano.

You, S.-H.; Gung, Y.; Lin, C.-H.; Konstantinou, K. I.; Chang, T.-M.; Chang, E. T. Y.; Solidum, R.

2013-03-01

46

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  

Microsoft Academic Search

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

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

2009-01-01

47

Tracking Fishing Activities of the Roviana Population in the Solomon Islands Using a Portable Global Positioning System Unit and a Heart Rate Monitor  

Microsoft Academic Search

In this article, I discuss the application of a portable global positioning system (GPS) receiver and a heart rate (HR) monitor for analyzing the fishing activities of the Roviana fisher-horticulturist population in the Solomon Islands. Each participant wore a portable GPS unit and a HR transmitter and recorder. Twelve trips relevant to fishing were recorded from departures to arrivals and

Takuro Furusawa

2012-01-01

48

Volcaniclastic sedimentation on the submarine slopes of a basaltic hotspot volcano: Piton de la Fournaise volcano (La Runion Island, Indian Ocean)  

E-print Network

1 Volcaniclastic sedimentation on the submarine slopes of a basaltic hotspot volcano: Piton de la Fournaise volcano (La Réunion Island, Indian Ocean) Francky Saint-Ange a,b,d,*, Patrick Bachèlery c hotspot volcanoes as exemplified by the Piton de la Fournaise volcano (La Réunion Island). The facies

Paris-Sud XI, Université de

49

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

PubMed Central

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

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

2005-01-01

50

An Overview of Geodetic Volcano Research in the Canary Islands  

NASA Astrophysics Data System (ADS)

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.

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

2014-08-01

51

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

NASA Astrophysics Data System (ADS)

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 at Deception Island since 2008. In the current survey we collaborate with the Spanish Army to add another permanent station that will be able to send to the IAG-UGR seismic information about the activity of the volcano during the winter, using a communications satellite (SPAINSAT). These advances simplify the field work and the data acquisition procedures, and allow us to obtain high-quality seismic data in real-time. These improvements have a very important significance for a better and faster interpretation of the seismo-volcanic activity and assessment of the volcanic hazards at Deception Island volcano.

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

52

Volcanoes  

NSDL National Science Digital Library

This resource provides general information about volcanoes. It illustrates the growth of a volcano, using Paricutin and Mt. St. Helens as examples of an active volcano and a lava dome. The terms extinct and dormant are also discussed. This site provides an explanation of why and how volcanoes form, zones of subduction, mid-ocean ridges, and hot spots. Deadly dangers associated with eruptions are discussed as is the use of a tiltmeter for prediction. The content center lesson describes a possible connection between the lost continent of Atlantis and the island of Santorini. Dissolved gasses in magma and the creation of a lava dome are both demonstrated in the hands-on section.

Johnson, Scott

53

Seismicity at Great Sitkin Volcano, Andreanof Islands, Alaska  

NASA Astrophysics Data System (ADS)

In 1999, the Alaska Volcano Observatory (AVO) installed 6 telemetered, short-period seismic stations around Great Sitkin (GS) volcano as part of a 14-station volcano-monitoring network in the Andreanof Islands of Alaska. Since that time, AVO has located over 890 earthquakes within 10 km of GS, the third-highest seismicity rate of the 23 volcanoes monitored by AVO over the period 1999-present. GS has arguably the most diverse background seismicity of all 23 volcanoes. Recorded seismicity includes several minutes-to-hour-long tremor episodes, shallow and deep (> 10 km) long-period events, swarms of distal volcano-tectonic earthquakes, and two of the largest earthquakes (ML 4.3) ever recorded by AVO near a monitored volcano. The rate and character of seismicity suggests that magma may be moving in the GS system. Of particular interest are two earthquake swarms that occurred in March-April and May-July of 2002. The first began March 17, consisted of more than 320 events located 15-20 km west of GS at depths of 10-25 km, and lasted for over 5 weeks. The mainshock (ML 4.3) occurred ~20 hours after the swarm's onset. The second swarm began May 28, consisted of over 460 events located 5-8 km southeast of GS at depths of 5-15 km, and lasted for over two months. The mainshock (also ML 4.3) occurred ~9 hours after the swarm's onset. This second swarm was preceded by two tremor episodes on May 27, one lasting for 20 minutes, the second lasting for an hour. Although the spatial relationship between the tremor episodes and the second swarm is unclear, the close temporal relationship suggests a common seismogenic process that could be magmatic in origin. We use cross-correlation and relative relocation techniques to more precisely determine the location and depth extent of the swarms, and calculate Coulomb stress changes to investigate whether static stress adjustments associated with magma intrusion beneath GS could have caused the two swarms.

Moran, S. C.; Stihler, S. D.; Power, J. A.; Lockhart, A. B.; Plucinski, T. A.; Paskievitch, J. F.; Dixon, J. P.

2002-12-01

54

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

PubMed Central

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 surveillance system in Isabel Province. Due to financial and logistical restraints local health authorities have concluded that a system of community-based vigilance to identify new arrivals in villages and direct them to have malaria testing is more feasible than formal screening at ports and airports. A surveillance response system to prevent introduction of malaria into Isabel Province can be integrated into the National Malaria Control Programme provided the operational steps are carefully planned with regards to human and financial resources. PMID:21834995

2011-01-01

55

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

NASA Technical Reports Server (NTRS)

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.

2001-01-01

56

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

NASA Technical Reports Server (NTRS)

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.

2001-01-01

57

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

Microsoft Academic Search

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

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

2008-01-01

58

Remote sensing for active volcano monitoring in Barren Island, India  

SciTech Connect

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.

Bhattacharya, A.; Reddy, C.S.S.; Srivastav, S.K. (National Remote Sensing Agency, Hyderabad (India))

1993-08-01

59

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

PubMed Central

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.

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

2014-01-01

60

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

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 overthrust, dismembered ophiolite derived from adjacent marginal basin crust. ?? 1989.

Wells, R. E.

1989-01-01

61

Transient self-potential anomalies associated with recent lava flows at Piton de la Fournaise volcano (Runion Island, Indian Ocean)  

E-print Network

be used to diagnose the cooling of recent lava flow on shield volcanoes. © 2009 Elsevier B.V. All rights volcano (Réunion Island, Indian Ocean) S. Barde-Cabusson a, ,1 , G. Levieux a,b , J.-F. Lénat a , A Fournaise volcano (Reunion Island, Indian Ocean). Repeated self-potential measurements are used to determine

Duputel, Zacharie

62

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

USGS Publications Warehouse

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.

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

2007-01-01

63

Economic and engineering considerations for geothermal development in the Makushin Volcano Region of Unalaska Island, Alaska  

SciTech Connect

Large vapor-dominated hydrothermal reservoirs are suspected to exist in the region marked by fumarole fields on the southeast flank of Makushin Volcano on Unalaska Island, Alaska. In this paper, economic and engineering considerations with respect to potential hydrothermal development in the Makushin Volcano region are presented.

Reeder, J.W.; Economides, M.J.; Markle, D.R.

1982-10-01

64

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

USGS Publications Warehouse

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.

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

2010-01-01

65

Toothpaste lava from the Barren Island volcano (Andaman Sea)  

NASA Astrophysics Data System (ADS)

Toothpaste lava is a basaltic lava flow type transitional between pahoehoe and aa and has been described from Paricutin, Kilauea and Etna volcanoes. Here we describe a spectacular example of toothpaste lava, forming part of a recent (possibly 1994-95) aa flow on the active volcano of Barren Island (Andaman Sea). This flow of subalkalic basalt shows abundant squeeze-ups of viscous toothpasate lava near its entry into the sea. The squeeze-ups are sheets and slabs, up to several meters across and tens of centimeters thick, extruded from boccas. They are often prominently curved, have striated upper surfaces with close-spaced, en echelon linear ridges and grooves, broad wave-like undulations perpendicular to the striations, and sometimes, clefts. Textural, geochemical, and Sr-Nd isotopic data on the squeeze-ups and the exposed aa flow core indicate very crystal-rich, viscous, and isotopically very homogeneous lava. We envisage that a greatly reduced speed of this viscous flow at the coastline, possibly aided by a shallowing of the basal slope, led to lateral spreading of the flow, which caused tension in its upper parts. This, with continued (albeit dwindling) lava supply at the back, led to widespread tearing of the flow surface and extrusion of the squeeze-ups. The larger slabs, while extruding in a plastic condition, curved under their own weight, whereas their surfaces experienced brittle deformation, forming the en echelon grooves. The extruded, detached, and rotated sheets and slabs were carried forward for some distance atop the very slowly advancing aa core, before the flow solidified.

Sheth, Hetu C.; Ray, Jyotiranjan S.; Kumar, Alok; Bhutani, Rajneesh; Awasthi, Neeraj

2011-04-01

66

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

USGS Publications Warehouse

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 at the Island of Hawaii, and longer-term growth of the Hawaiian chain as discrete islands rather than a continuous ridge, may record pulsed magma flow in the hotspot/plume source.

Lipman, Peter W.; Calvert, Andrew T.

2013-01-01

67

The First Historical Eruption of Anatahan Volcano, Mariana Islands  

NASA Astrophysics Data System (ADS)

The first historical eruption of Anatahan volcano occurred on May 10, 2003. The MARGINS office responded by authorizing helicopter surveillance and ship deployment to visit the volcano. The helicopter flight on May 19 allowed visual observations and identification of the east crater as the source of the eruption. The top of the plume was estimated to be at 10,000 ft - significantly less than the 30,000 ft of the initial blast. No bombs were ejected out of the east crater at this time but were falling back into the crater. The bombs looked irregular in shape, massive and were estimated to be a few m in diameter. Bombs and tephra samples were collected from the eastern side of the island when blasts were occurring at a rate of approx. 1 per 5min. The ship visit followed on May 21 to the western side of the island for collection of samples and SO2 flux measurements, along with maintenance of a previously deployed seismometer. Volcanic samples collected on Anatahan consisted of bombs, ash and scoria from the present eruption and old lavas (age unknown). The ash section on the western shore was 25 cm thick and consisted of the following sequence (bottom to top): 0-5 inversely? graded dark ash with scoria and pumice clasts (1-2 cm), 20-25 cm: well sorted clast-supported scoria (max 2 cm) with some fine ash. The maximum total thickness measured at a site 6 km from the east crater was approximately 45 cm. The sequence is interpreted as 1) initial blast 2) interaction of magma with water (from pre-existing hydrothermal system) as evidenced by accretionary lapilli 3) magmatic phase of the eruption producing juvenile material. Electron microprobe analyses of the pumice and scoria show uniform compositions of ~ 60wt% SiO2 in the glass; zoned plagioclase with average composition of 61% An, 37.7% Ab, 1.2% Or; pyroxenes (19.4% Wo, 53.4% En, 26.7% Fs) and Fe-Ti oxides. Sulfur and Cl contents are approx. 100 and 1500 ppm, respectively. Water content of the glass may be several wt% based on analytical totals. Volatile emissions from the volcano were measured by traversing under the plume with a ship-based COSPEC. Using wind speed data from NOAA (10-15 knots on May 21), we estimate the daily SO2 flux to be 3000 - 4500 tons. Our observations are consistent with the idea that the initial phreatic eruption evolved rapidly into a magmatic phase producing juvenile (and vesicular) material accompanied by a high SO2 flux. Details on the eruption products, chemical analyses, seismic measurements, and current monitoring efforts can be found in accompanying posters.

Fischer, T. P.; Hilton, D. R.; Demoor, J.; Jaffe, L.; Spilde, M. N.; Counce, D.; Camacho, J. T.

2003-12-01

68

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

USGS Publications Warehouse

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 third of the sedimentary column. The high Th/La in Anatahan magmas is consistent with shallow loss of the top 50 m of the sedimentary column during subduction. ?? 2005 Elsevier B.V. All rights reserved.

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, D. R.

2005-01-01

69

Volcanoes!  

NSDL National Science Digital Library

This webquest provides a information and links explaining the different types of volcanoes, lava flow, volcano locations, and volcano damage. There are links for students to research their own questions and a vocabulary list. A teacher page contains associated lesson plan criteria. There are links to building volcano models, virtual volcano field trips, and a volcano quiz.

1998-09-01

70

Seismic Observations of Westdahl volcano and Western Unimak Island Alaska: 1999-2005  

NASA Astrophysics Data System (ADS)

Westdahl volcano is a large basaltic shield volcano on the western end of Unimak Island Alaska in the Aleutian Island Arc. The volcano is topped by three separate vents, Pogromni Volcano, Faris Peak, and Westdahl Peak. The volcano is frequently active with known eruptions from Westdahl Peak in 1964, 1978, and 1991-92 that produced large basaltic lava flows. InSAR measurements indicate that Westdahl Volcano has been inflating at a slowly declining rate since 1992 (Lu et al., 2003). The Alaska Volcano Observatory has operated a network of six short-period seismometers on Westdahl Peak since 1998. Complementing this network are similar networks centered on Shishaldin and Akutan Volcanoes. Since 1999 more than 300 earthquakes have been located within 20 km of Westdahl Volcano. A volcano specific velocity model was determined for the western half of Uminak Island by simultaneously inverting for the velocity model and hypocentral earthquake locations using the program VELEST. Earthquakes located with the new model reveal five clusters of hypocenters: (a) a shallow cluster beneath Westdahl Peak, that largely occurred during a 24-hour period on January 7, 2004, (b) a concentration of 68 earthquakes with hypocenters ranging in depth from zero to eight km beneath Faris Peak occurring continually since 1999, (c) a diffuse cluster of long-period events northwest of Westdahl and Faris Peaks, (d) a cluster of 12 earthquakes near Pinnacle Rock, 12 km southwest of Westdahl Peak in October 2003, and (e) a cluster of 43 hypocenters near Unimak Bight, 20 km east of Westdahl Peak, that occurred between January and April 2004. Focal mechanisms were derived for four earthquakes in the Faris Peak cluster and four additional earthquakes that locate off the volcanic edifice (the four mechanisms are in the Pinnacle Rock cluster, the Unimak Bight cluster, and 20 km southeast and 30 km northeast of the volcano). Focal mechanisms in the Faris Peak cluster showed normal faulting with nodal planes trending north-south to northwest-southeast. Mechanisms of the off-volcano earthquakes are generally characterized by normal faulting with nodal planes trending southwest-northeast. These events are consistent with a stress field dominated by the Aleutian subduction zone. The Faris Peak mechanisms are not consistent with the presumed regional stress field and may reflect volcanic process. Lu et al., (2003) proposed the observed inflation of Westdahl Volcano resulted from a slowly pressurizing magma source at 6 km depth beneath Westdahl Peak. The observed seismicity is consistent with this model. Lu, Z., T. Masterlark, D. Dzurisin, and R. Rykhus, 2003, Magma supply dynamics at Westdahl volcano, Alaska, modeled from satellite radar interferometry, Alaska, J. Geophys. Res. 108, 2354, doi:10.1029/2002JB002311, 2003.

Dixon, J. P.; Power, J. A.; Stihler, S. D.

2005-12-01

71

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

PubMed Central

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

Peci, Luis Miguel; Berrocoso, Manuel; Fernandez-Ros, Alberto; Garcia, Alicia; Marrero, Jose Manuel; Ortiz, Ramon

2014-01-01

72

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

PubMed

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

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

2014-01-01

73

Volcanoes!!  

NSDL National Science Digital Library

5th grade students will be able to explain what makes a volcano erupt. 5th grade students will be able to list the effects that volcanoes have on the environment and people. Read through the page to gather more knowledge about volcanoes. After reading this, you should be able to explain what makes a volcano erupt Volcano Facts View a model of a volcano erupting Visual Model of a volcano erupting Use the web tool to make your own volcano erupt. Adjust the gas level and size to make ...

Fucaloro, Kailey

2009-09-15

74

Volcanoes  

NSDL National Science Digital Library

Create a poster about volcanoes Directions: Make a poster about volcanoes. (20 points) Include at least (1) large picture (15 points) on your poster complete with labels of every part (10 points). (15 points) Include at least three (3) facts about volcanoes. (5 points each) (15 points) Write at least a three sentence summary of your poster and volcanoes. (5 points) Use at ...

Walls, Mrs.

2011-01-30

75

Colonization of an island volcano, Long Island, Papua New Guinea, and an emergent island,  

E-print Network

of seed dispersing birds and mammals, and the Ficus fruit characters in¯uencing mode of colonization observed fruiting. Thirty-six vertebrate species occurring on Long Island are identi®ed as potential seed and fruit bats with generally smaller, red ®gs produced throughout the vertical structure of the forest

76

Deformation of Cerro Azul Volcano, Isabela Island, Galapagos With Radar Interferometry  

NASA Astrophysics Data System (ADS)

The Galapagos Islands are a volcanic island chain located off the coast of Ecuador in the Pacific Ocean. The islands have a recent eruptive history with 3 eruptions occurring within the last 15 years, including the 1998 eruption of Cerro Azul located on the southern end of Isabela Island. Analysis of Interferometric Synthetic Aperture Radar (InSAR) data covering Cerro Azul volcano reveals the volcano has been inflating prior to and after the 1998 eruption. Radarsat 1, ERS 1-2, and ENVISAT data spanning1992-2006 were used to compile interferograms showing the time dependence of deformation taking place. The results show continuous inflation of Cerro Azul over the time span with the exception of the 1998 eruption where there was a brief period of deflation during the eruption. Modeling was done with the data to help constrain the location of the inflation source and to determine the overall amount of deformation.

Baker, S.; Amelung, F.

2006-12-01

77

Evidence for two shield volcanoes exposed on the island of Kauai, Hawaii  

Microsoft Academic Search

The island of Kauai has always been interpreted as a single shield volcano, but lavas of previously correlated reversed-to-normal magnetic-polarity transitions on opposite sides of the island differ significantly in isotopic composition. Samples from west Kauai have 87Sr\\/86Sr < 0.7037, ?Nd >= 6.14, and 206Pb\\/204Pb > 18.25; samples from east Kauai have 87Sr\\/86Sr > 0.7037, ?Nd <= 6.14, and 206Pb\\/204Pb

Robin T. Holcomb; Peter W. Reiners; Bruce K. Nelson; Nuni-Lyn E. Sawyer

1997-01-01

78

Spatial variation of seismic b-values beneath Makushin Volcano, Unalaska Island, Alaska  

E-print Network

. Bridges , Stephen S. Gao Department of Geology, Kansas State University, Manhattan, KS 66506, USA Received beneath Makushin Volcano, Unalaska Island, Alaska using an earthquake catalog of 491 events that occurred of seismic stations, and filled circles are the epicenters of the earthquakes used in the study. The blue

Gao, Stephen Shangxing

79

Stress fields associated with the growth of a large shield volcano (La Palma, Canary Islands)  

Microsoft Academic Search

Measurements of dyke orientations and fault slip data have been taken in 39 stations located in the northern part of the island of La Palma (Canary Archipelago). These structures affect the materials belonging to the submarine growth stage and to the lower units of the subaerial shield volcano stage. Four sets of dykes have been distinguished (Groups I, II, III-1,

Carlos Fernández; Julio de la Nuez; Ramón Casillas; Encarnación García Navarro

2002-01-01

80

Dismantling processes of basaltic shield volcanoes - origin of the Piton des Neiges breccias - Reunion Island  

Microsoft Academic Search

Reunion Island is mainly composed by two volcanic massifs: the active Piton de la Fournaise to the southeast and the Piton des Neiges to the northwest that has been inactive for about 12000 years. The latter corresponds to a dismantled volcanic massif, deeply cut by valleys and by three vast depressions, called ``cirques'' around the centre of the volcano. They

A. Arnaud; B. Bachèlery; C. Cruchet

2003-01-01

81

Volcanic Structure of the Basaltic Shield Volcano of Socorro Island, Mathematician Ridge, Pacific Plate  

Microsoft Academic Search

Socorro Island is a pantellerite and perialkaline shield volcano built at the northern segment of the Mathematician ridge in the Pacific plate. Active spreading along the ridge terminated following major plate boundary re-organization and ridge jumping eastwards to the East Pacific Rise. Cessation of spreading and ridge jumping are recorded in the marine magnetic anomaly pattern that preserve a record

M. Escorza-Reyes; J. A. Pavon-Moreno; L. Perez-Cruz; J. U. Fucugauchi

2009-01-01

82

Mesoscale Eddies in the Solomon Sea  

NASA Astrophysics Data System (ADS)

Water mass transformation in the strong equatorward flows through the Solomon Sea influences the properties of the Equatorial Undercurrent and subsequent cold tongue upwelling. High eddy activity in the interior Solomon Sea seen in altimetric sea surface height (SSH) and in several models may provide a mechanism for these transformations. We investigate these effects using a mesoscale (4-km resolution) sigma-coordinate (ROMS) model of the Solomon Sea nested in a basin solution, forced by a repeating seasonal cycle, and evaluated against observational data. The model generates a vigorous upper layer eddy field; some of these are apparently shed as the New Guinea Coastal Undercurrent threads through the complex topography of the region, others are independent of the strong western boundary current. We diagnose the scales and vertical structure of the eddies in different parts of the Solomon Sea to illuminate their generation processes and propagation characteristics, and compare these to observed eddy statistics. Hypotheses tested are that the Solomon Sea mesoscale eddies are generated locally by baroclinic instability, that the eddies are shed as the South Equatorial Current passes around and through the Solomon Island chain, that eddies are generated by the New Guinea Coastal Undercurrent, or that eddies occurring outside of the Solomon Sea propagate into the Solomon Sea. These different mechanisms have different implications for the resulting mixing and property fluxes. They also provide different interpretations for SSH signals observed from satellites (e.g., that will be observed by the upcoming SWOT satellite).

Hristova, H. G.; Kessler, W. S.; McWilliams, J. C.; Molemaker, M. J.

2011-12-01

83

Volcanoes  

ERIC Educational Resources Information Center

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)

Kunar, L. N. S.

1975-01-01

84

Geochemical and Petrologic attributes of the PX1 Miocene pyroxenitic layered intrusion, root-zone of an ocean-island volcano, Fuerteventura (Canary Islands)  

Microsoft Academic Search

Fuerteventura is the easternmost island of the Canary archipelago, lying about 100 Km west of the Moroccan coast. This island allows direct observation of the hypabyssal root zone of an ocean island volcano, which is best illustrated in its uplifted Basal Complex Unit. This complex is composed of oceanic sediments of Mesozoic and Cenozoic age and records a remarkable magmatic

J. Allibon; F. Bussy; E. Lewin; H. Lapierre; M. Chiaradia

85

Volcanoes  

SciTech Connect

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.

Decker, R.W.; Decker, B.

1989-01-01

86

Volcanoes.  

ERIC Educational Resources Information Center

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…

Tilling, Robert I.

87

Volcanoes  

NSDL National Science Digital Library

In this lesson, students investigate the processes that build volcanoes, the types of rocks they create, the factors that influence different eruption types, and the threats volcanoes pose to their surrounding environments. They will also create a notebook of volcano characteristics and use what they have learned to identify physical features and eruption types in some real-life documented volcanic episodes.

2005-01-01

88

A Newly Recognized Shield Volcano Southwest of Oahu Island, Hawaii  

Microsoft Academic Search

During the 2001 Hawaiian cruise of the JAMSTEC research ship Kairei (with ROV-Kaiko; P.I.: E. Takahashi, Co P.I.: T. Kanamatsu), Seabeam mapping revealed a previously unidentified volcanic edifice (submarine shield) located about 100 km southwest of Oahu. The volcano (centered at 21\\\\deg35'N, 158\\\\deg45'W) is approximately 100 km in diameter and 0.5 km high with its summit at 4200 m depth.

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

2001-01-01

89

Numerical modeling of tsunami waves generated by the flank collapse of the Cumbre Vieja Volcano (La Palma, Canary Islands)  

E-print Network

Palma, Canary Islands): Tsunami source and near field effects S. M. Abadie,1 J. C. Harris,2 S. T. Grilli of the Cumbre Vieja Volcano (CVV; La Palma, Canary Island, Spain) through numerical simulations performed in two to further simulate propagation to the nearby islands. Unlike in earlier work on CVV, besides a similar

Kirby, James T.

90

Measuring deformation associated with magmatic processes at Cerro Azul Volcano, Galapagos Islands, Ecuador with InSAR  

Microsoft Academic Search

The Galapagos Islands are an active volcanic island chain in the eastern Pacific Ocean off the west coast of Ecuador. Cerro Azul volcano is located on the southern tip of Isabella Island and experienced two eruptions in 10 years. The eruptions started on September 15, 1998 and May 29, 2008 and lasted 51 days and 20 days respectively. Using radar

S. Baker; F. Amelung

2009-01-01

91

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

USGS Publications Warehouse

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.

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

2014-01-01

92

Effect of diel activity patterns and harvesting pressure on the diversity and biomass of sea cucumbers in Marovo Lagoon, Solomon Islands.  

PubMed

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. PMID:20349313

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

2010-05-01

93

3-D velocity model beneath Taal Volcano, Luzon Island Philippines  

NASA Astrophysics Data System (ADS)

We derive a three dimensional velocity model of seismic waves beneath Taal Volcano, Philippines, from about 2300 local earthquakes recorded by the Taal Volcano seismic network during the time period from March 2008 to March 2010. In the early data processing stage, with the cross-correlation functions of continuous record of station pairs, unexpected linear drifting of clock time was clearly identified. The drifting rates of each problematic station were determined and the errors were corrected before further processing. With the corrected data, we first determined initial locations by using the program HYPO71 and the reference 1-D global model ak135. 749 well-located events with 3381 P-wave and 2896 S-wave arrivals were used to derive the 'minimum 1-D velocity model' with the program VELEST developed by Kissling to further improve the 1-D velocity model and event locations. With the robust 1-D velocity model and improved event locations, we inverted a high-resolution 3-D velocity model by using the program LOTOS-10 developed by Koulakov. We present the derived 3-D model and discuss its tectonic implications.

You, S.; Konstantinou, K. I.; Gung, Y.; Lin, C.

2011-12-01

94

Volcanoes  

NSDL National Science Digital Library

Volcanoes is part of an online series of modules entitled Exploring the Environment. Emphasizing an integrated approach to environmental Earth Science education through problem based-learning, this module asks students to look at four different situations involving volcanoes, research the situations, and make decisions about them. Information about the three volcanic areas under exploration (Mt. Hood, Kilauea, and Yellowstone) is given through maps, movies, and videos. Additional information covers plate tectonics, locations of volcanoes, volcano monitoring and hazards, how to deal with volcano threats, lavas, eruption types, and risk analysis. Once students have gone through the information, they make real-life decisions about building near volcanoes, and the possibility of eruptions in the near future. There are teacher resources, a reference for problem-based learning, and links for more information.

95

Estimate of sulfate emitted from Sakurajima volcano to the Japanese Islands  

SciTech Connect

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.

Mizuno, Tateki; Maeda, Takahisa [National Institute for Environment and Resources, Ibaraki (Japan); Tanaka, Chie; Takeuchi, Kiyohide

1996-12-31

96

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

NASA Astrophysics Data System (ADS)

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 ?18O, between both monthly (r = 0.84) and monthly anomaly (r = 0.69) records. These results demonstrate that the Olasana D. heliopora coral ?18O record is a robust proxy of local surface ocean conditions. There is also a robust relationship between the Olasana ?18O record and NINO3.4 index of ENSO activity during 1938-2007, which provides confidence that the Olasana ?18O 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).

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

2012-12-01

97

Geochemical Composition of Volcanic Rocks from the May 2003 Eruption of Anatahan Volcano, Mariana Islands  

Microsoft Academic Search

The first historical eruption of Anatahan volcano began on May 10, 2003, from the easternmost of the island's two craters. Samples of tephra, scoria, and bombs, collected in May by a MARGINS-supported rapid-response team, were analyzed for 34 trace elements by solution ICP-MS at Boston University and Sr-Nd-Pb isotopic composition at the University of Texas-Dallas. The new eruptive materials can

J. A. Wade; T. Plank; R. Stern; D. Hilton; T. P. Fischer; R. Moore; F. Trusdell; M. Sako

2003-01-01

98

Identifying rift zones on volcanoes: an example from La Réunion island, Indian Ocean  

Microsoft Academic Search

We describe a methodology for identifying complex rift zones on recent or active volcanoes, where structures hidden by recent\\u000a deposits and logistical conditions might prevent carrying out detailed fieldwork. La Réunion island was chosen as a test-site.\\u000a We used georeferenced topographic maps, aerial photos and digital terrain models to perform a statistical analysis of several\\u000a morphometric parameters of pyroclastic cones.

Fabio Luca Bonali; Claudia Corazzato; Alessandro Tibaldi

2011-01-01

99

Geology, geochronology and geochemistry of a basanitic volcano, White Island, Ross Sea, Antarctica  

Microsoft Academic Search

White Island, Ross Sea, Antarctica is a Plio-Pleistocene basanite to tephriphonolite shield volcano, forming part of the Erebus Province, McMurdo Volcanic Group. Four new 40Ar\\/39Ar dates extend the age of surface volcanism from a previously determined 0.17 Ma to 5.05±0.31 Ma. A U\\/Pb age on zircon in an anorthoclasite nodule extends White Island magmatism back to 7.65±0.69 Ma.Volcanism was predominantly subaerial with eruption

Alan F. Cooper; Lotte J. Adam; Roseanne F. Coulter; G. Nelson Eby; William C. McIntosh

2007-01-01

100

Volcanoes!  

NSDL National Science Digital Library

This site presents a summary of current volcanic eruptions and images and videos of volcanoes on Earth. Discussions of the characteristics of volcanism on other worlds in our solar system are also presented and are accompanied by maps and imagery. Links to volcano observatories, parks, and monuments around the world are also included.

101

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

NASA Astrophysics Data System (ADS)

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.

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

2010-12-01

102

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

NASA Astrophysics Data System (ADS)

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 all three explosive events and the surge and fall deposits accumulated during the continuous phase of the third event only. The role of external water is under investigation, and observations on August 22 and 23 indicated several streams flowing from the base of the crater walls into a shallow lake in the bottom of the 1 km2 crater. The surge and fall deposits exposed on Kasatochi Island contain abundant accretionary lapilli indicating water involvement during the emplacement of these deposits. Tephra deposits observed on islands southwest of Kasatochi range in thickness from 6 cm, 30 km from the volcano, to minor amounts on eastern Adak Island, 80 km to the southwest. A fishing boat about 13 km southwest of Kasatochi received about 12 cm of coarse ash to medium lapilli tephra fall. Tephra deposits observed at 5 locations southwest of Kasatochi consist of single beds of normally graded medium to coarse lapilli tephra fall. The lack of recognizable stratigraphic breaks in the tephra deposits suggests that they were the products of a single fall event, likely the third explosion that produced the most ash rich plume.

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

2008-12-01

103

Volcanoes  

MedlinePLUS

... They have been known to knock down entire forests. Volcanic eruptions can be accompanied by other natural hazards, including earthquakes , mudflows and flash floods , rock falls and landslides , acid rain, fire , and (under special conditions) tsunamis . Active volcanoes in ...

104

Temporal source evolution and crustal contamination at Lopevi Volcano, Vanuatu Island Arc  

NASA Astrophysics Data System (ADS)

Here we present a new geochemical study of Lopevi volcano, one the most active volcanoes in the Vanuatu island arc. We focus on the temporally well-defined sequence of lava flows emitted since 1960, and for the first time, on pre-1960 volcanic products, including high-MgO basalts and felsic andesites, the most evolved lavas sampled so far on this island. This work reports the first Pb and Hf isotopic study of lavas from Lopevi island. These lavas display correlations between differentiation indexes such as SiO2 content and isotopic ratios. The felsic andesites extend the known correlations with both the least (Sr-Pb) and the most (Nd-Hf) radiogenic isotopic compositions on the island. Our results confirm that the rising magma interacted with the sub-arc crust. Assimilation-Fractional Crystallization (AFC) quantitative modeling of trace element ratios and isotopic compositions requires 1% and 10% of assimilated partial melts of a mafic oceanic crust to account for the pre- and post-1960 lavas, respectively. The post-1960 lavas differ from the former lavas emitted ~ 20 years earlier by enrichments in fluid mobile elements (K, Ba, Rb…), Th, and Light Rare Earth Elements (LREE). We ascribe these features to slight variations in the metasomatic agent added to the sub-arc mantle and ultimately derived from the subducted lithosphere. However, the contrasting time scales involved in subducted lithosphere dehydration and magma genesis, relative to the time elapsed between eruptions of the two lava series, suggest that two different portions of mantle which have undergone slightly different metasomatism, gave birth to the Lopevi lavas. These distinct magmas are still present beneath the volcano.

Beaumais, Aurélien; Chazot, Gilles; Dosso, Laure; Bertrand, Hervé

2013-08-01

105

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)

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].

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

2008-12-01

106

Space imaging of a 300 years old cooling magma chamber: Timanfaya volcano (Lanzarote, Canary Islands)  

NASA Astrophysics Data System (ADS)

Multitemporal space radar interferometry analysis between 1992 and 2000 revealed significantly deforming areas with a magnitude of 4-6 mm/yr of lengthening in the radar line of sight at Timanfaya volcano (Lanzarote, Canary Island). Timanfaya volcano erupted almost 300 years ago (1730-1736), along a 15 km-long fissure-feeding magmatic system, resulting in the longest and largest historical eruption of the Canarian archipelago to date, with >1 km3 of erupted basaltic lavas covering 200 km2. High surficial temperature (600 degrees-C at 13 m) and high heat flux measurements (150 mW/m2) suggest that the remnants of the magmatic chamber that fed the 1730-1736 are still partly molten. Here, we present preliminary models of the subsidence taking into account all available data, including geophysical data (heat flux, seismic, magnetotelluric and gravity), the geochemistry of freshly erupted lavas, upper mantle and crustal xenoliths, and structural geology.

Gonzalez, P. J.; Tiampo, K. F.

2010-12-01

107

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)

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 alkaline, silica-undersaturated melts (e.g. carbonatites, kimberlites). In-situ U-Pb dating conducted by LA-ICP-MS analysis of 18 zircon crystals (n= 94 total analyses) investigated here indicate a range in weighted mean (WM) 206Pb/238U ages between ~35 and ~52 Ma. The zircons from the Aluta region define a range of WM 206Pb/238U ages between 34.9 ± 1.7 Ma and 45.1 ± 2.7 Ma (2?), and correlate negatively with Zr/Hf ratios and total REE content. In contrast, the zircons from Kwainale define a uniform WM 206Pb/238U age spectrum yielding an age of 36.9 ± 0.6 Ma. The zircons from Faufaumela yield a range of WM 206Pb/238U dates from 38.1 ± 1.5 Ma to 51.9 ± 2.6 Ma, with the latter containing the lowest total REE content. The trace element compositions of the zircon crystals investigated here clearly indicate and support their mantle-derived origin, and their correlations with the age determinations (i.e. Aluta, Faufaumela zircons) suggest their progressive formation within an evolving mantle source region over a ~20 Ma interval. It is concluded that alnöite magmatism within the Ontong Java Plateau occurred over a prolonged period rather than a single event as previously suggested.

Simonetti, A.; Neal, C. R.

2009-12-01

108

Physical volcanology and structural development of Cerro Azul Volcano, Isabela Island, Galápagos: implications for the development of Galápagos-type shield volcanoes  

Microsoft Academic Search

Cerro Azul is an active basaltic shield volcano forming the southwestern end of Isabela Island in the western Galápagos Archipelago. Ten eruptions have been witnessed between 1932 and 1998, an average of one eruption every 6.6years. Although Cerro Azul has been constructed primarily by effusive Hawaiian-style eruptions, explosive hydrovolcanic eruptions have occurred intermittently from vents on the caldera floor and

Terry Naumann; Dennis Geist

2000-01-01

109

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

USGS Publications Warehouse

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 1981 and early 1982, but these were of lesser magnitude than the 15 May 1981 event. The 15 May lava is predominantly aa and ranges from 3 to > 30 m in thickness. In composition, it is a high-alumina basalt with small (< 1 mm long) phenocrysts of plagioclase and clinopyroxene (7%) that is more or less typical of basalt of the northern Marianas volcanoes. It contains slightly more SiO2 (52%), K2O, TiO2, and less Al2O3 and CaO than does the basalt of the last eruptive event of Mount Pagan Volcano in 1925. Gas analyses indicate that a large portion of air was introduced into the vent system through the porous volcanic edifice and that the carbon gases were not in equilibrium with the magma or each other. ?? 1984.

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

1984-01-01

110

Changes in eruptive magma compositions as precursors to ocean island volcano collapse? Supervisors: H Downes (BBK), S Day (UCL)  

E-print Network

, by investigating compositional changes in magmas that are associated with pre-collapse structural change. The project will investigate hypotheses that relate the magmatic changes to mechanisms by which incipientChanges in eruptive magma compositions as precursors to ocean island volcano collapse? Supervisors

Crawford, Ian

111

New geological and hydrogeological implications of the resistivity distribution inferred from audiomagnetotellurics over La Fournaise young shield volcano (Reunion Island)  

Microsoft Academic Search

An audiomagnetotelluric survey has been performed along an inactive flank of La Fournaise volcano massif in Reunion island, to study the subsurface resistivity structure. One-dimensional modelling of the AMT data at each site revealed an extensive low-resistivity (less than 10 ? m) zone at a few hundred meters below the surface. The significance of this unexpected conductive substratum is discussed

M. Courteaud; M. Ritz; B. Robineau; J. L. Join; J. Coudray

1997-01-01

112

Geochemical Composition of Volcanic Rocks from the May 2003 Eruption of Anatahan Volcano, Mariana Islands  

NASA Astrophysics Data System (ADS)

The first historical eruption of Anatahan volcano began on May 10, 2003, from the easternmost of the island's two craters. Samples of tephra, scoria, and bombs, collected in May by a MARGINS-supported rapid-response team, were analyzed for 34 trace elements by solution ICP-MS at Boston University and Sr-Nd-Pb isotopic composition at the University of Texas-Dallas. The new eruptive materials can be compared with an extensive suite of pre-existing volcanics (basalts through dacites) from Anatahan sampled by the USGS in 1990 and 1992, and analyzed by XRF and INAA. While most Mariana volcanoes erupt basalts and basaltic andesites, Anatahan is unusual for erupting a wide range of compositions, from basalt to dacite, and thus provides the best opportunity for addressing questions of magma evolution in this classic island arc. The newly erupted scoria and pumice are andesites and dacites that are among the most silicic materials erupted in the northern Mariana islands. The recent eruptives are highly homogeneous; 13 samples vary by only 3-5% relative standard deviation for incompatible trace elements. Isotopic compositions (0.703450 +/- 2 87Sr/86Sr and 18.806 +/- 5 206Pb/204Pb) are within the range of previously measured samples from Anatahan and other volcanic centers in the Marianas. The combined dataset for Anatahan defines virtually a single liquid line of descent. This is consistent with nearly-parallel REE patterns, and small variations in the ratios of the most incompatible trace elements (e.g., Th/Rb varies by <10% over the entire fractionation trend). Low values of Th/La and Th/Zr in Anatahan volcanics provide evidence against partial melting of crustal material as a source of the silicic magmas, as these ratios are highly senstive to apatite- and zircon- saturated crustal melts. Instead, the basalts, andesites and dacites of Anatahan appear to be related predominantly by crystal fractionation with little evidence for assimilation of crustal melts. The new data can also be used to make new inferences as to the source characteristics of Anatahan magma. Trace element ratios Th/La and Sm/La distinguish island-to-island differences in the subducted sediment components incorporated into the Mariana arc magmas. Most Mariana volcanics plot on a mixing line between depleted mantle and the bulk subducting sediment Th/La (0.14). Anatahan, however, mixes to slightly higher Th/La (0.16), which could be caused by the shallow loss of the top 50 m of the sedimentary column (pelagic clay) during subduction.

Wade, J. A.; Plank, T.; Stern, R.; Hilton, D.; Fischer, T. P.; Moore, R.; Trusdell, F.; Sako, M.

2003-12-01

113

Environmental impact of the acid fumarolic plume of a passively degassing volcano (Vulcano Island, Italy)  

NASA Astrophysics Data System (ADS)

This paper investigates the role played by the fumarolic plume of a passive degassing volcano in the genesis of rock coatings (RC) and in the introduction and re-distribution of metals and trace elements in the surficial environment. At La Fossa active volcano (Vulcano Island) and in the surrounding environment RC develop owing to exposure of the ground surface to the volcanic acid plume produced by the passive degassing of La Fossa. Significant positive anomalies of a wide variety of metals and trace elements (including Bi, Ag, Se, Te, Sb, Pb, As, Cu, Tl and Cd) were observed either in distal and proximal RC. Most of these anomalies are interpreted to be the result of the transport and subsequent deposition of trace elements, likely to form volatile compounds, in the fumarolic plume. Two main processes seem to control the geochemistry of RC: one is represented by the leaching and subsequent deposition of elements from the proximal toward the distal RC; the other is the direct input of trace elements carried by the emitted volcanic aerosol. The fact that most of the trace elements (particularly Pb, As, Tl, Bi, Te, Se, Cd) enriched in the RC of Vulcano are highly toxic and potentially dangerous to health in high concentration, indicates that the atmospheric metal injection by the quiescently degassing La Fossa volcano together with the subsequent deposition and remobilization by means of surficial waters may represent an environmental hazard that should be taken into account in evaluating the potential impact of volcanic air pollution on human health.

Fulignati, P.; Sbrana, A.; Clocchiatti, R.; Luperini, W.

2006-04-01

114

Pyroclastic density currents at Stromboli volcano (Aeolian Islands, Italy): a case study of the 1930 eruption  

NASA Astrophysics Data System (ADS)

Pyroclastic density currents (PDC) related to paroxysmal eruptions have caused a large number of casualties in the recent history of Stromboli. We combine here a critical review of historical chronicles with detailed stratigraphic, textural, and petrographic analyses of PDC deposits emplaced at Stromboli over the last century to unravel the origin of currents, their flow mechanism and the depositional dynamics. We focus on the 1930 PDC as they are well described in historical accounts and because the 1930 eruption stands as the most voluminous and destructive paroxysm of the last 13 centuries. Stromboli PDC deposits are recognizable from their architecture and the great abundance of fresh, well-preserved juvenile material. General deposit features indicate that Stromboli PDC formed due to the syn-eruptive gravitational collapse of hot pyroclasts rapidly accumulated over steep slopes. Flow channelization within the several small valleys cut on the flanks of the volcano can enhance the mobility of PDC, as well as the production of fine particles by abrasion and comminution of hot juvenile fragments, thereby increasing the degree of fluidization. Textural analyses and historical accounts also indicate that PDC can be fast (15-20 m/s) and relatively hot (360-700 °C). PDC can thus flow right down the slopes of the volcano, representing a major hazard. For this reason, they must be adequately taken into account when compiling risk maps and evaluating volcanic hazard on the Island of Stromboli.

Di Roberto, A.; Bertagnini, A.; Pompilio, M.; Bisson, M.

2014-06-01

115

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

NASA Astrophysics Data System (ADS)

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.

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

2006-12-01

116

Morphology of Piton de la Fournaise basaltic shield volcano (La Réunion Island): Characterization and implication in the volcano evolution  

Microsoft Academic Search

The topography of Piton de la Fournaise volcano (PdF) differs from the classic view of basaltic shield volcanoes as it is characterized by (1) several steep slope zones on its flanks and (2) a large U-shaped caldera, the Enclos-Grand Brûlé structure (EGBS). Most of these structures were previously interpreted as the scars of lateral landslides, the deposits of which cover

Laurent Michon; Francky Saint-Ange

2008-01-01

117

Problems in Using Underground Water Temperatures in Volcanic Surveillance: the Case of Volcano Island (Eolian Islands, Sicily, Italy)  

NASA Astrophysics Data System (ADS)

Measuring underground water temperatures in a network of wells, together with many other geochemical and geophysical data, is a useful tool in medium-long term surveillance of active volcanic areas. The study case here presented deals with Volcano Island (Eolian Islands, Sicily, Italy). About 20 years of observations are presented; they have been acquired either during spot campaigns, every 1-3 months, either by continuous monitoring (sampling period of 2 hours). Although the interested active volcanic area has an extension of few square kilometers, data analysis pointed out a surprising variability in space and time of the information acquired, and in particular: a) Monthly temperature variations show a frequency related to the hydrological cycle, except some wells located in a piezometric high (Camping Sicilia well) or in distal positions respect to the La Fossa Crater (EAS and Discarica wells). b) Some wells subjected to continuous monitoring, affected (Le Calette) or not (Camping Sicilia) by seasonal variations, show high frequency (from few hours to few days) pulsation of several Celsius degrees. The above mentioned variations are sometimes related to seismic events (Gulf of Patti earthquakes, April 2002). c) Water table elevations from sea level, measured at the same time of temperature, highlight the presence of some wells (EAS, Casamento) where the piezometric surface is normally below the sea, despite they are very near to the coast line. The elements above discussed point out the presence of a complex multi-layered aquifer, with very different interactions between fresh, sea and volcanic waters, that are reflected in space and time variations of measured B.H.T. values. The implementation of an accurate hydrogeological model is then to be considered as preventive and fundamental in order to correctly design a surveillance activity based on underground fluids monitoring in this area.

Madonia, P.; Capasso, G.; Favara, R.

2002-12-01

118

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

NASA Astrophysics Data System (ADS)

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.

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

2011-11-01

119

The eruptive history of Morne Jacob volcano (Martinique Island, French West Indies): Geochronology, geomorphology and geochemistry of the earliest volcanism in the recent Lesser Antilles arc  

Microsoft Academic Search

Martinique is the Lesser Antilles Island where the most complete volcanic history of the arc can be found from the Oligocene to the present time. In this study, we focused on the construction of Morne Jacob shield volcano in Martinique, which is the largest volcano of the Lesser Antilles. We have dated twenty representative samples from the Morne Jacob, by

Aurélie Germa; Xavier Quidelleur; Shasa Labanieh; Pierre Lahitte; Catherine Chauvel

2010-01-01

120

Volcano-tectonic implications of 3-D velocity structures derived from joint active and passive source tomography of the island of Hawaii  

Microsoft Academic Search

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

Jaewoo Park; Julia K. Morgan; Colin A. Zelt; Paul G. Okubo

2009-01-01

121

Petrologic observations and multiphase dynamics in highly-crystalline magmatic mushes sourcing Galápagos Island volcanoes  

NASA Astrophysics Data System (ADS)

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 crystal pile inflates and the injected melt creates crystal-poor fingers through the mush. These regions are unstable and eventually lead to mush collapse. Repetition of this cycle can drive efficient mixing of the magma chamber. We quantify the ability of the mush to mix using the Lacey statistical mixing index. We compare this value for the results of various open-system reintrusion events within the mush as a means to explore the dynamics that occur.

Schleicher, J.; Bergantz, G. W.; Geist, D.

2013-12-01

122

Petroleum potential of volcanogenic and volcano-sedimentary rocks in ancient and recent island arcs: Caucasus, Komandorskie, and Kuril islands, eastern Kamchatka  

SciTech Connect

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.

Levin, L.E. (VNIIZarubezhgeologia, Moscow (Russian Federation))

1993-09-01

123

2005 Volcanic Activity in Alaska, Kamchatka, and the Kurile Islands: Summary of Events and Response of the Alaska Volcano Observatory  

USGS Publications Warehouse

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.

McGimsey, R. G.; Neal, C. A.; Dixon, J. P.; Ushakov, Sergey

2008-01-01

124

Magnetic structure of Loihi Seamount, an active hotspot volcano in the Hawaiian Island chain  

E-print Network

The use of geophysical techniques to image the interiors of active volcanoes can provide a better understanding of their structure and plumbing. The need for such information is especially critical for undersea volcanoes, whose environment makes...

Lamarche, Amy J.

2004-09-30

125

The 1976 1982 Strombolian and phreatomagmatic eruptions of White Island, New Zealand: eruptive and depositional mechanisms at a `wet' volcano  

Microsoft Academic Search

White Island is an active andesitic-dacitic composite volcano surrounded by sea, yet isolated from sea water by chemically sealed zones that confine a long-lived acidic hydrothermal system, within a thick sequence of fine-grained volcaniclastic sediment and ash. The rise of at least 106 m3 of basic andesite magma to shallow levels and its interaction with the hydrothermal system resulted in

B. F. Houghton; I. A. Nairn

1991-01-01

126

CURRICULUM VITAE MARJORIE SOLOMON  

E-print Network

Skills Intervention for Higher-Functioning Children and Adolescents with Autism Spectrum Disorder Selection Committee 2007-present Autism Research Training Program (T-32 MH073124), Mentor #12;CV Solomon 2-2006 Coordinator Family Support Core, Autism Phenome Project 2005, 2009 Facilitator, Adolescence Module of Child

Nguyen, Danh

127

Measuring deformation associated with magmatic processes at Cerro Azul Volcano, Galapagos Islands, Ecuador with InSAR  

NASA Astrophysics Data System (ADS)

The Galapagos Islands are an active volcanic island chain in the eastern Pacific Ocean off the west coast of Ecuador. Cerro Azul volcano is located on the southern tip of Isabella Island and experienced two eruptions in 10 years. The eruptions started on September 15, 1998 and May 29, 2008 and lasted 51 days and 20 days respectively. Using radar data from Radarsat-1 and Envisat satellites, the deformation before, during, and after these eruptions was measured using interferometric synthetic aperture radar (InSAR). Radarsat-1 data cover the 1998 eruption and Envisat data is available in 2008. Compared to the 2008 data, the time coverage for the 1998 eruption is not as frequent, but still allows for measuring the deformation during the eruption. Continuous radar data coverage between the eruptions allows us to see the state of the volcano leading up to the 2008 eruption. Using data from 8 different Envisat tracks in 2008, we measured the deformation associated with two separate eruptive phases of the volcano. Acquisitions on May 30 and 31, and June 2, 3, 5 and 6 show the deformation associated with the intrusion of magma responsible for fissures on the SE flank ceased by June 5, 2008. Using these data, it is possible to measure the amount of deformation during each of the eruptive phases and model the source processes at those times.

Baker, S.; Amelung, F.

2009-12-01

128

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)

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 interest in the scientific community and society due to their volcanic features and specific hazards associated with volcanic activity.

Hernandez Perez, P. A.; Tanaka, H.; Miyamoto, S.; Perez, N.; Barrancos, J.; Padron, E.; Hernandez, I.

2012-12-01

129

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)

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 interest in the scientific community and society due to their volcanic features and specific hazards associated with volcanic activity.

Hernández, Iñigo; Hernández, Pedro; Pérez, Nemesio; Tanaka, Hiroyuki; Miyamoto, Seygo; Barrancos, José; Padrón, Eleazar

2013-04-01

130

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

Microsoft Academic Search

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

John S. Pallister; Frank A. Trusdell; Isabelle K. Brownfield; David F. Siems; James R. Budahn; Steven F. Sutley

2005-01-01

131

The 2003 phreatomagmatic eruptions of Anatahan volcano—textural and petrologic features of deposits at an emergent island volcano  

Microsoft Academic Search

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

John S. Pallister; Frank A. Trusdell; Isabelle K. Brownfield; David F. Siems; James R. Budahn; Steven F. Sutley

2005-01-01

132

Characteristics of Offshore Hawai';i Island Seismicity and Velocity Structure, including Lo';ihi Submarine Volcano  

NASA Astrophysics Data System (ADS)

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 the regional velocity model (HG50; Klein, 1989) in the shallow lithosphere above 16 km depth. This is likely a result of thick deposits of volcaniclastic sediments and fractured pillow basalts that blanket the southern submarine flank of Mauna Loa, upon which Lo';ihi is currently superimposing (Morgan et al., 2003). A broad, low-velocity anomaly was observed from 20-40 km deep beneath the area of Pahala, and is indicative of the central plume conduit that supplies magma to the active volcanoes. A localized high-velocity body is observed 4-6 km deep beneath Lo';ihi's summit, extending 10 km to the North and South. Oriented approximately parallel to Lo';ihi's active rift zones, this high-velocity body is suggestive of intrusion in the upper crust, similar to Kilauea's high-velocity rift zones.

Merz, D. K.; Caplan-Auerbach, J.; Thurber, C. H.

2013-12-01

133

Seismic monitoring at Deception Island volcano (Antarctica): the 2010-2011 survey  

NASA Astrophysics Data System (ADS)

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 the seismic activity and an efficient seismo-volcanic surveillance. The data are processed and analyzed using the SEISAN database management software. In addition to the seismic network, we deployed a small-aperture seismic array south of Fumarole Bay. It is composed by 9 vertical and 1 three-component short-period stations. The 24-bit data acquisition system samples these 12 channels at 100 sps. There is also a permanent seismic station operating since 2008 and located near GdC, that is very useful for the preliminary evaluation of the seismicity at the start of the survey. This station is composed by a 16-s electrolytic seismometer (Eentec SP400) and a 24-bit datalogger (Eentec DR4000) sampling at 100 sps. During the 2010-2011 survey we identified 33 regional earthquakes, 80 volcano-tectonic (VT) earthquakes, and 929 long-period (LP) events. The volcanic alert system has remained green (the lowest level) at all times. The seismic activity has been similar to previous surveys and remained within limits that are normal for the island.

Martín, R.; Carmona, E.; Almendros, J.; Serrano, I.; Villaseñor, A.; Galeano, J.

2012-04-01

134

SAR-based Estimation of Glacial Extent and Velocity Fields on Isanotski Volcano, Aleutian Islands, Alaska  

NASA Astrophysics Data System (ADS)

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, yielding 83.0% producer's accuracy (errors of omission) and 86.1% user's accuracy (errors of commission). These results represent a refinement of a decades-old entry from the USGS National Hydrography Dataset (NHD). The information gained from this study could strengthen management practices by helping decision makers understand the ecological and economic consequences of glacial change. This procedure could be repeated in similar locations worldwide to provide communities with accurate, quantitative information about their changing glacial resources.

Sousa, D.; Lee, A.; Parker, O. P.; Pressler, Y.; Guo, S.; Osmanoglu, B.; Schmidt, C.

2012-12-01

135

The submarine flanks of Anatahan Volcano, commonwealth of the Northern Mariana Islands  

E-print Network

that 67% of the volcano's submarine flanks are covered with volcaniclastic debris and 26% is lava flows volcanoes may be characterized by sediment flows of unconsolidated volcaniclastic debris instead of mass and the spring of 2004. This was part of the Submarine Ring of Fire project, which is a multi-year study

Chadwick, Bill

136

Enhancement of sub-daily positioning solutions for surface deformation monitoring at Deception volcano (South Shetland Islands, Antarctica)  

NASA Astrophysics Data System (ADS)

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 its applicability to other volcanoes worldwide.

Prates, G.; Berrocoso, M.; Fernández-Ros, A.; García, A.

2013-02-01

137

Nd and Sr-isotopic compositions of lavas from the northern Mariana and southern Volcano arcs: implications for the origin of island arc melts  

Microsoft Academic Search

Nd- and Sr-isotopic data are reported for lavas from 23 submarine and 3 subaerial volcanoes in the northern Mariana and southern Volcano arcs. Values of eNd range from +2.4 to +9.5 whereas 87Sr\\/86Sr ranges from 0.70319 to 0.70392; these vary systematically between and sometimes within arc segments. The Nd-and Sr-isotopic compositions fall in the field of ocean island basalt (OIB)

P. N. Lin; R. J. Stern; J. Morris; S. H. Bloomer

1990-01-01

138

Nd and Sr-isotopic compositions of lavas from the northern Mariana and southern Volcano arcs: implications for the origin of island arc melts  

Microsoft Academic Search

Nd- and Sr-isotopic data are reported for lavas from 23 submarine and 3 subaerial volcanoes in the northern Mariana and southern Volcano arcs. Values of ?Nd range from +2.4 to +9.5 whereas 87Sr\\/86Sr ranges from 0.70319 to 0.70392; these vary systematically between and sometimes within arc segments. The Nd-and Sr-isotopic compositions fall in the field of ocean island basalt (OIB)

P. N. Lin; R. J. Stern; J. Morris; S. H. Bloomer

1990-01-01

139

Unusual Signals Recorded by Ocean Bottom Seismometers in the Caldera of Deception Island Volcano: Biological Activity or Hydrothermally Generated Seismicity?  

NASA Astrophysics Data System (ADS)

As part of an active source land-sea tomography experiment, ocean bottom seismometers (OBSs) were deployed at Deception Island Volcano, Antarctica, in January 2005. Following the tomography study, three OBSs were left for a month inside the flooded caldera and ten on the outer slopes of the volcano to record seismo-volcanic signals. The OBS sensor package included three-orthogonal 1-Hz geophones but no hydrophone. The OBSs were deployed in water depths of 125 to 143 m inside the caldera and at depths of 119 to 475 m on the volcano's flanks. Only two volcano-tectonic earthquakes and three long period events were recorded by the network. However, the OBSs inside the caldera recorded over 4,500 unusual seismic events. These were detected by only one station at a time and were completely absent from OBSs on the flank of the volcano and from land stations deployed on the island. The signals had a dominant frequency of 5 Hz and were one to ten seconds long. Event activity in the caldera was variable with the number of events per hour ranging from 0 up to 60 and the level of activity decreasing slightly over the study period. We categorize the signals into three types based on waveform characteristics. Type 1 events have an impulsive onset and last 1 to 2 s with characteristics that are consistent with the impulse response of a poorly coupled OBS. Type 2 events typically last 2 to 4 s and comprise a low amplitude initial arrival followed less than a second later by a more energetic second phase that looks a Type 1 event. Type 3 events last up to 10 s and have more complex waveforms that appear to comprise several arrivals of varying amplitudes. Type 1 events are similar to the 'fish-bump' signals reported from previous studies that attributed them to biological activity. The consistent timing and relative amplitudes of the two arrivals for Type 2 events are difficult to explain by animals randomly touching the OBSs. Type 3 events are quite similar in frequency, duration, and signal characteristics to long-period seismic events recorded by an onshore seismic array deployed in an earlier study at Deception Island. Particle motions suggest that Type 3 events may be surface waves while the particle motions for Type 1 and Type 2 events are ambiguous and unlike any signals recorded by land arrays at the volcano. Binomial tests of the event distribution show no significant changes in the rate of events with time of day that would be indicative of a biological source. Since the events are entirely absent in biologically productive waters outside the caldera, we postulate that they may be volcanic signals related to hydrothermal flow across the seafloor in the flooded caldera of Deception Island. Future OBS deployments at Deception Island should include a hydrophone to discriminate unambiguously between biological and volcanic signals.

Bowman, D. C.; Wilcock, W. S.

2011-12-01

140

Deformation of Cerro Azul Volcano, Isabela Island, Galapagos With Radar Interferometry  

Microsoft Academic Search

The Galapagos Islands are a volcanic island chain located off the coast of Ecuador in the Pacific Ocean. The islands have a recent eruptive history with 3 eruptions occurring within the last 15 years, including the 1998 eruption of Cerro Azul located on the southern end of Isabela Island. Analysis of Interferometric Synthetic Aperture Radar (InSAR) data covering Cerro Azul

S. Baker; F. Amelung

2006-01-01

141

The submarine volcano eruption at the island of El Hierro: physical-chemical perturbation and biological response.  

PubMed

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

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

142

Argon geochronology of late Pleistocene to Holocene Westdahl volcano, Unimak Island, Alaska  

USGS Publications Warehouse

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.

Calvert, Andrew T.; Moore, Richard B.; McGimsey, Robert G.

2005-01-01

143

Boron isotopic composition of fumarolic condensates from some volcanoes in Japanese island arcs  

Microsoft Academic Search

Boron samples from 40 fumarolic condensates from volcanoes in the Ryukyu arc (Satsuma Iwo-jima and Shiratori Iwo-yama) and the North-east Japan arc (Usu-shinzan, Showa-shinzan, Esan and Issaikyo-yama) all have 11 B \\/ 10 B ratios close to 4.07. Higher values, from 4.09 to 4.13, were only observed in condensates from volcanoes in the southernmost end of the North-east Japan arc

Masao Nomura; Tadeo Kanzaki; Takejiro Ozawa; Makoto Okamoto; Hidetake Kakihana

1982-01-01

144

A Comparison of MODIS and DOAS Sulfur Dioxide Measurements of the April 24, 2004 Eruption of Anatahan Volcano, Mariana Islands  

NASA Astrophysics Data System (ADS)

Measurements of volcanic SO2 emissions provide insight into the processes working below a volcano, which can presage volcanic events. Being able to measure SO2 in near real-time is invaluable for the planning and response of hazard mitigation teams. Currently, there are several methods used to quantify the SO2 output of degassing volcanoes. Ground and aerial-based measurements using the differential optical absorption spectrometer (mini-DOAS) provide real-time estimates of SO2 output. Satellite-based measurements, which can provide similar estimates in near real-time, have increasingly been used as a tool for volcanic monitoring. Direct Broadcast (DB) real-time processing of remotely sensed data from NASA's Earth Observing System (EOS) satellites (MODIS Terra and Aqua) presents volcanologists with a range of spectral bands and processing options for the study of volcanic emissions. While the spatial resolution of MODIS is 1 km in the Very Near Infrared (VNIR) and Thermal Infrared (TIR), a high temporal resolution and a wide range of radiance measurements in 32 channels between VNIR and TIR combine to provide a versatile space borne platform to monitor SO2 emissions from volcanoes. An important question remaining to be answered is how well do MODIS SO2 estimates compare with DOAS estimates? In 2004 ground-based plume measurements were collected on April 24th and 25th at Anatahan volcano in the Mariana Islands using a mini-DOAS (Fischer and Hilton). SO2 measurements for these same dates have also been calculated using MODIS images and SO2 mapping software (Realmuto). A comparison of these different approaches to the measurement of SO2 for the same plume is presented. Differences in these observations are used to better quantify SO2 emissions, to assess the current mismatch between ground based and remotely sensed retrievals, and to develop an approach to continuously and accurately monitor volcanic activity from space in near real-time.

Meier, V. L.; Scuderi, L.; Fischer, T.; Realmuto, V.; Hilton, D.

2006-12-01

145

Interview with Solomon Nwaka.  

PubMed

Solomon Nwaka was born in Nigeria and grew up seeing at first hand the impact of neglected diseases. His research efforts have taken him across the globe, in both the developed and developing world. Following posts in academia, industry and at the Medicines for Malaria Venture, he is now at the WHO where he is engaged in initiating schemes to support research into neglected diseases in developing countries, notably the African Network for Drugs and Diagnostics Innovation, which is now an organization under the United Nations Economic Commission for Africa. He speaks to Future Medicinal Chemistry about what inspired him to take up a career in neglected disease research and how the developing world should lead the effort to tackle some of the diseases that most affect them. PMID:21879840

Nwaka, Solomon

2011-09-01

146

Detailed gravity study of the offshore structure of Piton de la Fournaise volcano, Reunion Island  

NASA Astrophysics Data System (ADS)

We present an interpretation of gravity data acquired in 1984 by the French R/V Jean Charcot on the submarine part of the eastern flank of Piton de la Fournaise volcano. We comment on the Bouguer anomaly map and give a quantitative interpretation of three gravity profiles. The main results are that a gravity high over Grand Brûlé, the lower subaerial part of the eastern flank, does not extend far offshore and that an anomalous topographic feature, discovered in 1982 on the submarine eastern flank, is characterized by a large negative anomaly. We propose three hypotheses to explain the origin of this anomaly, i. e., it marks the site of a new volcano, or it is a consequence of lateral volcanism from a volcano older than Piton de la Fournaise, or more probably, it represents a great landslide deposit.

Rousset, Dominique; Bonneville, Alain; Lenat, Jean-François

1987-12-01

147

Imaging spatial and temporal seismic source variations at Sierra Negra Volcano, Galapagos Islands using back-projection methods  

NASA Astrophysics Data System (ADS)

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 coherent seismic energy from all possible events to all available receivers, we generate a movie showing how seismic sources change spatially and temporally during the analysis period. This approach utilizes data from the entire seismic record and could ultimately provide a more complete understanding of how seismic sources change throughout the eruptive sequence rather than during a particular eruption event. This information could help to 1) answer fundamental questions about volcano-tectonic processes and 2) make more accurate assessments of volcanic hazards. Preliminary results from application of the methodology to seismic data collected by a dense array of 3-component geophones at El Tatio Geyser Field in northern Chile during October 2012 will also be introduced.

Kelly, C. L.; Lawrence, J. F.; Ebinger, C. J.

2013-12-01

148

2005 Volcanic Activity in Alaska, Kamchatka, and the Kurile Islands: Summary of Events and Response of the Alaska Volcano Observatory.  

National Technical Information Service (NTIS)

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...

C. A. Neal, J. P. Dixon, R. G. McGimsey

2007-01-01

149

Unravelling the Geometry of Unstable Flanks of Submarine Volcanoes by Magnetic Investigation: the Case of the "sciara del Fuoco" Scar (stromboli Volcano, Aeolian Islands)  

NASA Astrophysics Data System (ADS)

Stromboli is the easternmost island of the Aeolian Archipelago (Tyrrhenian Sea) and one of the most active Mediterranean volcanoes. The volcanic edifice rises over 3000 m above the surrounding seafloor, from a depth of about 2000 m b.s.l. to 924 m a.s.l. The north-western flank of volcano is deeply scarred by a destructive collapse event occurred ca. 5000 years ago, and forming a big horseshoe-shaped depression, known as "Sciara del Fuoco" (SdF). This depression, 3 Km long and 2 Km wide, is supposed to extend into the sea down to 700 m b.s.l., while further basinward it turns into a fan-shaped mounted deposit down to about 2600 m b.s.l., where it merges the so-called "Stromboli Canyon". Since its formation, emerged and submerged portions of the SdF have been progressively filled by the volcanic products of the persistent activity of the Stromboli Volcano. In the last 10 years, two paroxysmal eruptions occurred in the Stromboli Volcano, during 2002-2003 and February-April 2007. During both events, the SdF has been partially covered by lava flows and affected by slope failures, also causing (for the 2002-2003 event) a local tsunami. Since the 1990's, and especially after the last two paroxysms, the submerged extension of the SdF has been intensively investigated by using swath bathymetry data. We focused principally on the magnetic anomaly pattern of the submerged SdF since the chaotic depositional system virtually cancels magnetic remanence (which at Stromboli can reach 5-10 A/m values), thus lowering magnetic residual intensity. On July 2012 we acquired new detailed sea-surface magnetic data of the SdF from the shoreline to about 7 km offshore, where the depth is more than 1800 m b.s.l. We collected data thanks to the Italian Navy ship "Nave Aretusa" and by using the Marine Magnetics SeaSPY magnetometer. At the same time, new bathymetric data were acquired in the same area by using a Kongsberg Marine multibeam systems. Although the morphologic features of the submarine prosecution of the SdF system were already studied and unveiled, the complete description of the in-depth extension of the system and the overall volume estimation is still poorly known. This has important implications for the hazard assessment of the landslide structure and most generally of the entire volcanic edifice. The application of a classical geomagnetic prospection to describe a landslide feature is an uncommon procedure yet it can be considered as innovative approach, having the advantages of effectiveness, low cost and expedition typical of the geomagnetic survey. Here we present the interpretation of the newly acquired high-resolution magnetic dataset, thanks to susceptibility and magnetic remanence values gathered from on-land rock samples at Stromboli. A 3D inverse model is here proposed, allowing a full definition of the submerged SdF structure geometry.

Muccini, F.; Cocchi, L.; Carmisciano, C.; Speranza, F.; Marziani, F.

2012-12-01

150

ACTIVE VOLCANOES OF THE KURILE ISLANDS --A Quick Reference Stratovolcano with summit crater  

E-print Network

the early 20 century, it is likely thatmanyeruptionswentundocumented. The Sakhalin Volcanic Eruption provided by colleagues at the Sakhalin Department of the Geophysical Surveyofthe Sakhalin Is. Km ak achta KEY Number on map - VOLCANO (1 - 6 ­ monitored by KVERT, 7 - 36 ­ monitored

151

Combining CSD and isotopic microanalysis: Magma supply and mixing processes at Stromboli Volcano, Aeolian Islands, Italy  

Microsoft Academic Search

Integrating isotopic microanalysis with other analytical techniques creates powerful new methodologies for understanding the evolution of rock samples at the sub-grain scale. Here we present Crystal Size Distribution (CSD) data for a 26,000 year old sample from Stromboli Volcano and accompanying isotopic microanalysis of the phenocrysts. A technique, called the ICSD plot, is introduced which given stated assumptions allows the

D. J. Morgan; D. A. Jerram; D. G. Chertkoff; J. P. Davidson; D. G. Pearson; A. Kronz; G. M. Nowell

2007-01-01

152

Variations in Seismic Anisotropy with time on Volcanoes in Kyushu Island, Southern Japan  

NASA Astrophysics Data System (ADS)

Using a newly developed automatic processing technique, we have calculated shear wave splitting on and near three active volcanoes in Kyushu, southern Japan (Aso, Unzen and Sakurajima). Shear wave splitting is considered to be caused by aligned cracks and microcracks. The polarisation of the first arriving phase, ?, gives a measure of the crack orientation, which is expected to align with the maximum principal stress. The delay time dt between the two phases depends upon the crack density and the path length. High quality measurements include the following: a) over 1700 from local events recorded and located near Aso Volcano between 2001 and 2008; b) over 2000 from local events recorded and located near Unzen volcano between 1988 and 1997 (spanning the most active period of seismic activity related to the large eruption in 1991); c) over 600 from regional events originating in the subducting Phillipine Sea plate recorded near Sakurajima volcano between 2003 and 2005, (during which time numerous small eruptions have occcurred, and GPS measurements have been modeled as caused by inflation of a Mogi source and a near-vertical crack). Most of the stations were located in boreholes or tunnels, providing excellent signals. Common features at all three volcanoes are that stations closest to the craters yield the fewest good measurements, and even those tend to give varying results at closely spaced stations. Scattering from the volcanic edifice may be making the S waves difficult to pick, and the local stresses may be varied. Stations on the volcanic flanks give many good measurements. Some stations yield variations in ? and dt that depend upon the earthquake location. But at each volcano, some stations show changes that are better explained by variations in time than in space. Where GPS measurements are available, the variations sometimes but not always correlate with previously-modeled inflation or deflation events. The temporal variations in ? are large, ranging from 30° at some stations to 90 ° at other stations. These results will allow us to test models of stress changes with time on the volcanoes.

Savage, M. K.; Ohkura, T.; Umakoshi, K.; Shimizu, H.; Kohno, Y.; Iguchi, M.; Wessel, A.; Mori, J.

2008-12-01

153

The submarine volcano eruption at the island of El Hierro: physical-chemical perturbation and biological response  

NASA Astrophysics Data System (ADS)

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. (A) Natural color composite from the MEdium Resolution Imaging Spectrometer (MERIS) instrument aboard ENVISAT Satellite (European Space Agency), (November 9, 2011 at 14:45 UTC). Remote sensing data have been used to monitor the evolution of the volcanic emissions, playing a fundamental role during field cruises in guiding the Spanish government oceanographic vessel to the appropriate sampling areas. The inset map shows the position of Canary Islands west of Africa and the study area (solid white box). (B) Location of the stations carried out from November 2011 to February 2012 at El Hierro. Black lines denote transects A-B and C-D.

Fraile-Nuez, E.; Santana-Casiano, J.; Gonzalez-Davila, M.

2013-12-01

154

Boron isotopic composition of fumarolic condensates from some volcanoes in Japanese island arcs  

NASA Astrophysics Data System (ADS)

Boron samples from 40 fumarolic condensates from volcanoes in the Ryukyu arc (Satsuma Iwo-jima and Shiratori Iwo-yama) and the North-east Japan arc (Usu-shinzan, Showa-shinzan, Esan and Issaikyo-yama) all have 11B /10B ratios close to 4.07. Higher values, from 4.09 to 4.13, were only observed in condensates from volcanoes in the southernmost end of the North-east Japan arc (Nasu-dake), the northern part of the Izu-Bonin arc (Hakone), and the North Mariana arc (Ogasawara Iwo-jima). These higher values suggest geological interaction of the magmas with sea-water enriched in 11B.

Nomura, Masao; Kanzaki, Tadao; Ozawa, Takejiro; Okamoto, Makoto; Kakihana, Hidetake

1982-11-01

155

The submarine eruption of the Bombarda volcano, Milos Island, Cyclades, Greece  

Microsoft Academic Search

The Milos volcanic field includes a well-exposed volcaniclastic succession which records a long history of submarine explosive\\u000a volcanism. The Bombarda volcano, a rhyolitic monogenetic center, erupted ?1.7 Ma at a depth <200 m below sea level. The aphyric\\u000a products are represented by a volcaniclastic apron (up to 50 m thick) and a lava dome. The apron is composed of pale

M. Rinaldi; M. Campos Venuti

2003-01-01

156

Combining CSD and isotopic microanalysis: Magma supply and mixing processes at Stromboli Volcano, Aeolian Islands, Italy  

Microsoft Academic Search

Integrating isotopic microanalysis with other analytical techniques creates powerful new methodologies for understanding the evolution of rock samples at the sub-grain scale. Here we present Crystal Size Distribution (CSD) data for a 26,000 year old sample from Stromboli Volcano and accompanying isotopic microanalysis of the phenocrysts. A technique, called the ICSD plot, is introduced which given stated assumptions allows the integration

D. J. Morgan; D. A. Jerram; D. G. Chertkoff; J. P. Davidson; D. G. Pearson; A. Kronz; G. M. Nowell

2007-01-01

157

O-saturated island arc low-K tholeiite magmas: a case study of the Izu-Oshima volcano in the Izu arc  

NASA Astrophysics Data System (ADS)

Island arc low-K tholeiites are basaltic magmas erupting from frontal arc volcanoes of juvenile arcs associated with the subduction of old and cold plates. We investigated the origins of geochemical variation in volcanic rocks having multiple phase saturated liquid compositions from the Izu-Oshima volcano in the northern Izu arc. The geochemical variations in the liquids fall between two endmember trends, namely higher- and lower-Al/Si trends. Polybaric differentiation of H2O-saturated melts between a 4-km-deep magma chamber and degassed melts near the surface should be responsible for the observed variation in the liquids.

Hamada, Morihisa; Okayama, Yuko; Kaneko, Takayuki; Yasuda, Atsushi; Fujii, Toshitsugu

2014-12-01

158

IESID: Automatic system for monitoring ground deformation on the Deception Island volcano (Antarctica)  

NASA Astrophysics Data System (ADS)

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.

Peci, Luis Miguel; Berrocoso, Manuel; Páez, Raúl; Fernández-Ros, Alberto; de Gil, Amós

2012-11-01

159

Assessment of the exposure of islanders to ash from the Soufriere Hills volcano, Montserrat, British West Indies  

PubMed Central

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 crystalline silica to be at risk of developing mild silicosis. If volcanic activity were to deposit further ash over the occupied areas of the island during the coming years, the risks of silicosis will become more substantial. PMID:12151608

Searl, A; Nicholl, A; Baxter, P

2002-01-01

160

Gaseous transport and deposition of gold in magmatic fluid: evidence from the active Kudryavy volcano, Kurile Islands  

NASA Astrophysics Data System (ADS)

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, Sn, Ag, and Al), Cu-Zn-Fe-In sulfides, In-bearing Pb-Bi sulfosalts, cannizzarite, rheniite, cadmoindite, and kudriavite. Although most of these minerals are fine-grained, they are strongly idiomorphic with textures such as gas channels and lamellar, banded, skeletal, and dendrite-like crystals, characteristic of precipitation from a gas phase. The identified textures and mineral assemblages at Kudryavy volcano can be used to interpret geochemical origins of both ancient and modern ore deposits, particularly gold-rich porphyry and related epithermal systems.

Yudovskaya, Marina A.; Distler, Vadim V.; Chaplygin, Ilya V.; Mokhov, Andrew V.; Trubkin, Nikolai V.; Gorbacheva, Sonya A.

2006-03-01

161

Magma storage and migration associated with the 2011-2012 El Hierro eruption: Implications for crustal magmatic systems at oceanic island volcanoes  

NASA Astrophysics Data System (ADS)

Starting in July 2011, anomalous seismicity was observed at El Hierro Island, a young oceanic island volcano. On 12 October 2011, the process led to the beginning of a submarine NW-SE fissural eruption at ~15 km from the initial earthquake loci, indicative of significant lateral magma migration. Here we conduct a multifrequency, multisensor interferometric analysis of spaceborne radar images acquired using three different satellite systems (RADARSAT-2, ENVISAT, and COSMO-SkyMed (Constellation of Small Satellites for Mediterranean Basin Observation)). The data fully captures both the pre-eruptive and coeruptive phases. Elastic modeling of the ground deformation is employed to constrain the dynamics associated with the magmatic activity. This study represents the first geodetically constrained active magmatic plumbing system model for any of the Canary Islands volcanoes, and one of the few examples of submarine volcanic activity to date. Geodetic results reveal two spatially distinct shallow (crustal) magma reservoirs, a deeper central source (9.5 ± 4.0 km), and a shallower magma reservoir at the flank of the southern rift (4.5 ± 2.0 km). The deeper source was recharged, explaining the relatively long basaltic eruption, contributing to the observed island-wide uplift processes, and validating proposed active magma underplating. The shallowest source may be an incipient reservoir that facilitates fractional crystallization as observed at other Canary Islands. Data from this eruption supports a relationship between the depth of the shallow crustal magmatic systems and the long-term magma supply rate and oceanic lithospheric age. Such a relationship implies that a factor controlling the existence/depth of shallow (crustal) magmatic systems in oceanic island volcanoes is the lithosphere thermomechanical behavior.

González, Pablo J.; Samsonov, Sergey V.; Pepe, Susi; Tiampo, Kristy F.; Tizzani, Pietro; Casu, Francesco; Fernández, José; Camacho, Antonio G.; Sansosti, Eugenio

2013-08-01

162

Slope instability induced by volcano-tectonics as an additional source of hazard in active volcanic areas: the case of Ischia island (Italy)  

Microsoft Academic Search

Ischia is an active volcanic island in the Gulf of Naples whose history has been dominated by a caldera-forming eruption (ca.\\u000a 55 ka) and resurgence phenomena that have affected the caldera floor and generated a net uplift of about 900 m since 33 ka.\\u000a The results of new geomorphological, stratigraphical and textural investigations of the products of gravitational movements\\u000a triggered by volcano-tectonic events

Marta Della Seta; Enrica Marotta; Giovanni Orsi; Sandro de Vita; Fabio Sansivero; Paola Fredi

2011-01-01

163

The 1976–1982 Strombolian and phreatomagmatic eruptions of White Island, New Zealand: eruptive and depositional mechanisms at a ‘wet’ volcano  

Microsoft Academic Search

White Island is an active andesitic-dacitic composite volcano surrounded by sea, yet isolated from sea water by chemically sealed zones that confine a long-lived acidic hydrothermal system, within a thick sequence of fine-grained volcaniclastic sediment and ash. The rise of at least 106 m3 of basic andesite magma to shallow levels and its interaction with the hydrothermal system resulted in

B F Houghton; I A Nairn

1991-01-01

164

Volcanogenic fluorine in rainwater around active degassing volcanoes: Mt. Etna and Stromboli Island, Italy.  

PubMed

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. PMID:12493195

Bellomo, S; D'Alessandro, W; Longo, M

2003-01-01

165

Edifice growth, deformation and rift zone development in basaltic setting: Insights from Piton de la Fournaise shield volcano (Réunion Island)  

Microsoft Academic Search

The overall morphology of basaltic volcanoes mainly depends on their eruptive activity (effusive vs. explosive), the geometry of the rift zones and the characteristics of both endogenous and exogenous growth processes. The origin of the steep geometry of the central cone of Piton de la Fournaise volcano, which is unusual for a basaltic effusive volcano, and its deformation are examined

Laurent Michon; Valérie Cayol; Ludovic Letourneur; Aline Peltier; Nicolas Villeneuve; Thomas Staudacher

2009-01-01

166

Geomorphic evolution of the Piton des Neiges volcano (Réunion Island, Indian Ocean): Competition between volcanic construction and erosion since 1.4 Ma  

NASA Astrophysics Data System (ADS)

Réunion Island (Indian Ocean) is a volcanic complex whose eruptive history was dominated by the activity of two main edifices: Piton des Neiges (PN) and Piton de la Fournaise (PF) volcanoes. The tropical climate induces erosion processes that permanently compete with volcanic constructional processes. Exposed to the trade winds and associated heavy rainfalls, the northeastern part of the island exhibits the most complex morphological evolution. Geomorphological analysis, performed on a 50 m DEM and associated to new K-Ar ages has clarified the overall history of PN volcano. Each massif is assigned to one of the main building stages of the edifice. In addition, the arrangement of these different massifs reveals that the eruptive phases have led to successive relief inversions and successive excavations of large central depressions in the proximal area. As a result, the younger massifs are always located in more proximal parts of the volcano, the youngest being close to the edifice center. In distal areas, early lava flows were channeled into valleys incised along the massif boundaries, leading to a more complex geochronological organization. Quantitative study of the dissection of PN volcano allows us to propose a minimum eroded volume of 101 ± 44 and 105 ± 41 km 3 for the Mafate and Cilaos "Cirques" (depressions), respectively, during the last 180 kyr and a minimum average long-term erosion rate of 1.2 ± 0.4 km 3/ka. This leads us to estimate the removed volume during the whole history of PN volcano (> 1000 km 3) as equivalent to the volume of the deposits identified on the submarine flanks of Piton des Neiges volcano. Therefore, as regressive erosion appears to be the prevailing geomorphic process during the whole PN history, it questions the presence of major flank collapses younger than 1.4 Ma on this volcano. Erosion processes have largely been neglected in recent models, but our study emphasizes them as a key component of landscape development and a major process in the morphological evolution of Réunion Island that has to be fully integrated in future studies.

Salvany, Tiffany; Lahitte, Pierre; Nativel, Pierre; Gillot, Pierre-Yves

2012-01-01

167

Long- and short-term temporal variations of the diffuse CO2 emission from Timanfaya volcano, Lanzarote, Canary Islands  

NASA Astrophysics Data System (ADS)

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 means of a thermocouple together with soil gas samples collected during the campaign of 2010 to evaluate the chemical and isotopic composition of soil gases. Diffuse CO2 emission values have ranged between non detectable values to 34 g m-2 d-1, and most of the study area have shown relatively low values, around the detection limit of the instrument (~0,5 g m-2 d-1). Higher soil CO2 diffuse emission values were observed where thermal anomalies occur, indicating a convective mechanism transport of gas from depth at these areas. Total CO2 outputs of the study area have been estimated in the range 41-518 t d-1 during the study period. Long-term temporal variation on total CO2 diffuse emission shows a peak recorded on winter 2011, suggesting a seasonal control on the CO2 emission. As part of the volcanic surveillance program and to understand the dynamics of CO2 diffuse emission at Timanfaya volcanic zone, an automatic geochemical station was installed in July 2010 to monitor the CO2 emission and investigate the short-term temporal variation. Time series of soil CO2 efflux shows also a close relationship with seasonal changes mainly due to rainfall.

Hernández, P. A.; Padilla, G.; Calvo, D.; Padrón, E.; Melian, G.; Dionis, S.; Nolasco, D.; Barrancos, J.; Rodríguez, F.; Pérez, N.

2012-04-01

168

Extreme Spatial Variability in Microbial Mat Communities from Submarine Hydrothermal Vents Located at Multiple Volcanoes along the Mariana Island Arc  

NASA Astrophysics Data System (ADS)

Volcanic arc systems are the most active tectonic feature in the world, but are among the least studied. The Western Pacific contains ~20,000 km of volcanic arcs, of which only ~2% have been systematically surveyed. The lack of comprehensive knowledge of volcanic arcs is compounded by the incredible variability found in relatively short distances. The complex source history of hydrothermal fluids and the variable depths of seamounts found in island arc systems result in highly variable vent chemistries and therefore unique microbial habitats within relatively short distances. The Mariana Island Arc was surveyed in 2003 and areas with suspected hydrothermal activities were identified for targeted remote operating vehicle (ROV) exploration and sampling in 2004. Sixteen microbial mat samples from five seamounts ranging from 145-1742 mbsl and from ambient to 222°C were collected and analyzed with quantitative PCR (Q-PCR), cluster analysis of terminal restriction length polymorphism (T-RFLP) community fingerprints, and by clone library analysis of small subunit ribosomal rDNA genes. The microbial mat communities from the Mariana Island Arc exhibit greater spatial variability within their community structure than microbial mats sampled from mid-ocean ridge or hotspot hydrothermal vents from a comparable scale. Microbial communities from the summit of NW Eifuku Volcano are dominated by putative iron-oxidizing phylotypes at the Yellow Top and Yellow Cone Vent sites, but are dominated by sulfur-oxidizing ?-Proteobacteria at the Champagne Vent site. Mats collected at the Mat City Vent site on E Diamante Seamount contained nearly three times as much biomass as any other mat sample collected, and is dominated by a Planctomyces phylotype. Hydrothermal sediments at the Fish Spa site located on Daikoku Seamount contained the second highest biomass detected and supported a large community of flatfish indicating a direct route for biomass being channeled up the food chain. The microbial community at Fish Spa consists of a highly diverse assemblage of Bacteroidetes, ?-Proteobacteria and Firmicutes. While in contrast, the microbial mat at the Iceberg Vent site on NW Rota I is dominated by a single phylotype of ?-Proteobacteria.

Davis, R. E.; Moyer, C. L.

2005-12-01

169

Spatio-temporal evolution of a dispersed magmatic system and its implications for volcano growth, Jeju Island Volcanic Field, Korea  

NASA Astrophysics Data System (ADS)

Jeju Island is the emergent portion of a basaltic volcanic field developed over the last c. 1.8 Ma on continental crust. Initial volcanism comprised dispersed, small-volume (< 0.01 km3) alkali basaltic eruptions that incrementally constructed a tuff pile. Lavas and scoria from continuing small-scaled monogenetic volcanism capped this foundation. From c. 0.4 Ma large-volume (> 1 km3) eruptions began, with lavas building a composite shield. Three magma suites can be recognized: Early Pleistocene high-Al alkali (HAA), and Late Pleistocene to Holocene low-Al alkali (LAA) and subalkali (SA). The chemical similarity between small-volume and primitive large-volume eruptions suggests analogous parent magmas and fractionation histories that are independent of erupted volumes. The large-volume magmas evolved to trachyte, which erupted in two distinct episodes: the HAA Sanbangsan suite at c. 750 ka and the LAA Hallasan suite at c. 25 ka. Sr and Nd isotopes indicate that the early trachytes were contaminated by upper crustal material, whereas the later magmas were not. Both suites bear a Nd isotope signature indicative of lower crustal interaction. Sub-suites transitional between HAA and LAA, and between LAA and SA, indicate that melting occurred in discrete, but adjacent, mantle domains. Throughout the evolution of this volcano, each magma batch erupted separately, and a centralized plumbing system was never created. The Island's central peak (Mt. Halla 1950 m a.s.l.) is therefore not a sensu stricto stratovolcano, but marks the point of peak magma output in a distributed magmatic system. Jeju's shape and topography thus represent the spatial variation of fertility of the mantle below it. An increase in melt production in the Late Pleistocene was related to a deepening of the melting zone due to regional tectonic rearrangements. Temporal coincidences between magmatic pulses on Jeju and large-scale caldera eruptive events along the nearest subduction system in Kyushu, Japan, suggest that tectonic extension and changing strain rates may drive volcanism on a regional basis, influencing the intraplate volcanism of Jeju Island.

Brenna, Marco; Cronin, Shane J.; Smith, Ian E. M.; Sohn, Young Kwan; Maas, Roland

2012-09-01

170

Volcano Live  

NSDL National Science Digital Library

Volcano Live contains maps of volcanoes from around the world, a kids' page that provides volcano education links for teachers and students, a volcano glossary, volcano news, links to live video cams of volcanoes, geography and volcano information of countries around the world, and video clips of active volcanoes. There is also information for travelling to volcanoes, a volcano photo section, a section on the destruction of Pompeii, a volcanology section, and volcano safety rules.

Seach, John

171

2009 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: summary of events and response of the Alaska Volcano Observatory  

USGS Publications Warehouse

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.

McGimsey, Robert G.; Neal, Christina A.; Girina, Olga A.; Chibisova, Marina; Rybin, Alexander

2014-01-01

172

Lead isotopes behavior in the fumarolic environment of the Piton de la Fournaise volcano (Réunion Island)  

NASA Astrophysics Data System (ADS)

The recent activity of the Piton de la Fournaise volcano offers a rare opportunity to address the issue of Pb isotope behavior in volcanic fumaroles, as the composition of the degassing source is accurately and precisely known. Gas sublimates formed between 2007 and 2011 at temperature ranging from 400 to ca. 100 °C include Na-K sulfate (aphthitalite), Ca-Cu sulfate (e.g., gypsum), Na sulfate (thenardite), Ca-Mg-Al-Fe fluoride (e.g., ralstonite) and native sulfur. The high-temperature deposits show trace element patterns typical of volcanic gas (with Pb concentration up to 836 ppm) while the low-temperature deposits are depleted in most volatile elements (Pb <1 ppm) with the exception of Pd and Tl (in fluorides) and Se (in native sulfur). Only for low-temperature fluoride samples do Pb isotope compositions plot significantly outside the field of lavas. The isotopic shift is ascribed to leaching ubiquitous unradiogenic phases (e.g., sulfides) by acidic gas condensates. The similarity in Pb isotope signature between lavas and sublimate samples more representative of the gas phase (sulfates) indicates that the net fractionation of Pb isotopes resulting from volatilization and condensation processes is smaller than the precision of Pb isotope measurements (better than 60 ppm/a.m.u.). The absence of net fractionation could result from negligible isotope fractionation during Pb volatilization followed by extensive condensation of gaseous Pb, with possibly significant isotopic fractionation at this stage. Although this scenario has to be refined by more direct measurement of the gas phase, and its general applicability tested, it suggests that a small fraction (<10%) of initially volatilized Pb ultimately escapes to the atmosphere, while the remaining dominant fraction is trapped in sublimates. As sublimates are rapidly dissolved and entrained by runoff, the fumarolic environment appears as a factory efficiently transferring isotopically unfractionated Pb from magmas towards the hydrological system and seawater. Resolving very small isotopic differences between magmas and their gaseous products remains an analytical challenge. High-precision Pb isotope measurements rest not only on instrumental performance but also on high-yield chemistry, as Pb isotopes drastically fractionate (800 ppm/a.m.u.) upon elution on anionic resin. For 50% Pb recovery, the estimated isotopic bias is plus or minus 60-80 ppm/a.m.u., depending on which of the early (isotopically light) or late (isotopically heavy) Pb fraction is lost.

Vlastélic, I.; Staudacher, T.; Deniel, C.; Devidal, J. L.; Devouard, B.; Finizola, A.; Télouk, P.

2013-01-01

173

K-Ar analyses of the post-caldera lavas of Bratan volcano in Bali Island, Indonesia — Ar isotope mass fractionation to light isotope enrichment  

NASA Astrophysics Data System (ADS)

The post-caldera lavas of Bratan volcano in Bali Island, Indonesia were collected for whole rock chemical analyses and K-Ar analyses. Major and trace element chemistry shows that the lavas are basalts to andesites and typical of subduction-related tectonic setting. The 38Ar/36Ar ratios are 0.1851 ± 3-0.1875 ± 2 and the 40Ar/36Ar, 294.3 ± 0.3-301.6 ± 0.1, which strongly suggest that the mass fractionation to light isotope enrichment took place. The effect of the groundwater on magma is common on the basis of systematic mass fractionation of the atmospheric Ar enriched in lighter isotopes. This case was under the mass fractionation law analyzed numerically, giving the mass fractionation correction ages (14 ± 15, 31 ± 6, 55 ± 22, 66 ± 23, 94 ± 32 and 125 ± 51 ka) consistent with the volcano stratigraphy though the magma composition that changed frequently in time.

Ryu, Sunyoung; Kitagawa, Hiroshi; Nakamura, Eizo; Itaya, Tetsumaru; Watanabe, Koichiro

2013-08-01

174

Phreatomagmatism driven by magma withdrawal at ';open system' volcanoes: contrasting cases of Kilauea and White Island (Invited)  

NASA Astrophysics Data System (ADS)

Transitions to phreatomagmatic explosions at persistent open-system volcanoes require special conditions. One trigger can be conduit wall failure possibly accompanying magma withdrawal, promoting bulk interaction between already fragmented wall rock, magmatic volatiles and/or magma. In all cases a prerequisite is the existence of significant subsurface void spaces, on length scales of hundreds of meters, in the upper portions of the conduit. These void spaces are often abandoned conduit segments from previous eruption cycles, loosely blocked near the surface with fragmental debris. We describe here three case studies where: 1) Collapse to depths of c. 200 m did not trigger mixing with magma but temporarily blocked a major flux of magmatic volatiles, causing a impulse transient vent-clearing explosion (Halemaumau crater, Kilauea 19 March 2008), 2) Collapse following Strombolian explosions creating a 330 m by 100 m crater accompanied by significant explosive interaction between failed blocks of unconsolidated wall rock hosting a high temperature geothermal system and the retreating basic andesite magma (White Island February 1978), 3) The subsidence and disappearance of a Kilauea lava lake was followed by wall collapse and deepening of the crater to below the water table, leading to an 17-day interval characterized by approximately 80 short-lived discrete explosions (Halemaumau, May 1924). These events demonstrate the complex influence of external factors such as strength of the wall rocks and hydrology on the form of the explosions and also a clear but often over-looked role for mechanically decoupled magmatic volatiles in otherwise phreatic/phreatomagmatic eruptions.

Houghton, B. F.; Swanson, D. A.; White, J. D.

2013-12-01

175

Nd- and Sr-isotopic compositions of lavas from the northern Mariana and southern Volcano arcs: implications for the origin of island arc melts  

NASA Astrophysics Data System (ADS)

Nd- and Sr-isotopic data are reported for lavas from 23 submarine and 3 subaerial volcanoes in the northern Mariana and southern Volcano arcs. Values of ?Nd range from +2.4 to +9.5 whereas 87Sr/86Sr ranges from 0.70319 to 0.70392; these vary systematically between and sometimes within arc segments. The Nd-and Sr-isotopic compositions fall in the field of ocean island basalt (OIB) and extend along the mantle array. Lavas from the Volcano arc, Mariana Central Island Province and the southern part of the Northern Seamount Province have ?Nd to +10 and 87Sr/86Sr=0.7032 to 0.7039. These are often slightly displaced toward higher 87Sr/86Sr at similar ?Nd. In contrast, those lavas from the northern part of the Mariana Northern Seamount Province as far north as Iwo Jima show OIB isotopic characteristics, with ?Nd and 87Sr/86Sr=0.7035 to 0.7039. Plots of 87Sr/86Sr and ?Nd versus Ba/La and (La/Yb)n support a model in which melts from the Mariana and Volcano arcs are derived by mixing of OIB-type mantle (or melts therefrom) and a metasomatized MORB-type mantle (or melts therefrom). An alternate interpretation is that anomalous trends on the plots of Nd- and Sr-isotopic composition versus incompatible-element ratios, found in some S-NSP lavas, suggest that the addition of a sedimentary component may be locally superimposed on the two-component mixing of mantle end-members.

Lin, P. N.; Stern, R. J.; Morris, J.; Bloomer, S. H.

1990-09-01

176

High Resolution, Pb Isotope Variability Within Historic Eruptions of the Cumbre Vieja Volcano, La Palma, Canary Islands  

NASA Astrophysics Data System (ADS)

The range of time-scales over which ocean island basalt (OIB) magmatism taps different mantle heterogeneities is a fundamental dynamic of mantle plumes. The variability of long-lived radiogenic isotopes in OIB magmas erupted on time scales less than 100 years has been addressed primarily for Hawaiian magmas (e.g., Pietruszka et al., 2001). Similar data are relatively sparse for hot spots with low buoyancy fluxes. The Canary Islands have low eruption rates and have been historically active. The Cumbre Vieja volcano in southern La Palma, Canary Islands, has six, well-mapped, historic eruptions spanning the entire southern rift zone. We have investigated Pb isotope compositional variations expressed in magmas erupted in a series of events spanning 500 years (the 1480, 1585, 1677, 1712, 1949, and 1971 eruptions), and sampled in detail two of these events (the 1677 and 1712 eruptions) to document isotopic variability at the month to year time-scale as well as the 100-year time scale. Previous Pb isotope investigations of Cumbre Vieja did not reveal systematic variations (e.g., Marcantonio et al., 1995 and Ovchinnikova et al., 1995). With denser sampling (40 samples) and higher precision MC-ICP-MS analyses, we observe that radiogenic Pb isotope compositions over the 500 year eruptive history decrease systematically with time (206Pb/204Pb =19.669 -- 19.611, 207Pb/ 204Pb = 15.618 -- 15.602, 208Pb/204Pb = 39.530 -- 39.430). Detailed Pb isotope analyses of the 1677 and 1712 eruptions indicate isotopically homogeneous magmas within a single eruptive episode. However, samples from both the 1677 and 1712 eruptions display mineralogic evidence for magma mixing: 1677 samples include isotopically distinct gabbroic xenoliths, and both magmas have reversely- zoned clinopyroxene phenocrysts with corroded cores of Na-rich salite, and zoned overgrowths of Al-rich salite. With time, an increasing proportion of partial melt from a less radiogenic end-member within a heterogeneous plume explains the 500 year trend. Alternatively, higher level mixing of two magmas would require sequential recharge of a single magma chamber that feeds the entire rift zone. A single chamber is structurally unlikely, and not consistent with geochemical and petrographic trends (Klü gel, 1999). From the decompressing plume, batches of melt with homogeneous Pb isotope ratios are extracted periodically. To generate mineralogic disequilibrium, each batch must segregate into a zoned magma chamber or multiple, isolated pockets and differentiate at multiple levels. Prior to eruption, magma from these pockets may remix, producing reversely-zoned clinopyroxene phenocrysts. Isotopic homogeneity is preserved within a given magma batch. In the Canary Islands, the minimum time period for eruptive basalts to reflect resolvable mantle isotope heterogeneity is on the order of 50 - 100 years. A. Klügel, K. A. Hoernle, H.-U. Schmincke, J. D. L. White, J. Geophys. Res. 105(B3), 5997 (2000). F. Marcantonio, A. Zindler, T. R. Elliot, H. Staudigel, Earth Planet. Sci. Lett. 133, 397 (1995). G. V., Ovchinnikova, B. V., Belyatskii, I. M., Vasil'eva, L. K., Levsky, A. F., Grachev, V., Arana, I. J., Mitjavila, Petrologiya, 3, 195 (1995). A. J. Pietruszka, K. H. Rubin, M. O. Garcia, Earth Planet. Sci. Lett. 186, 15 (2001).

Locke, J. A.; Peterson, B. T.; Nelson, B. K.

2005-12-01

177

2008 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory  

USGS Publications Warehouse

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.

Neal, Christina A.; McGimsey, Robert G.; Dixon, James P.; Cameron, Cheryl E.; Nuzhdaev, Anton A.; Chibisova, Marina

2011-01-01

178

2007 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory  

USGS Publications Warehouse

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.

McGimsey, Robert G.; Neal, Christina A.; Dixon, James P.; Malik, Nataliya; Chibisova, Marina

2011-01-01

179

Flow-By-Flow Mapping on Fogo, Cape Verde Islands, Reveals Long Term Variations in Eruption Distributions and Volcanic Edifice Structure at a Shield-Stage Oceanic Island Volcano  

NASA Astrophysics Data System (ADS)

Most maps of large oceanic island shield volcanoes show the lava flows and scoria cones of individual historic and subhistoric eruptions as individual units but then resort to grouping older rocks into larger stratigraphic units. This grouping makes it difficult to characterize long-term progressive trends in volumes of individual eruptions and distributions of eruptive vents, but is commonly made necessary by poor exposure, limited compositional variation between individual eruptions, and burial of older by younger volcanic rocks. In contrast, work on Fogo, Cape Verde Islands has involved flow-by-flow mapping of rocks erupted over an extended period of tens of thousands of years, as part of the process of mapping the island and producing a 1:25 000 scale geological map for research and hazard management purposes. Around three-quarters of the island is characterized by low rainfall and limited vegetation cover, with erosion restricted to narrow gullies. Only in small areas on the windward side of the island do higher rainfall, thick vegetation and deeper erosion combine to prevent flow-by-flow mapping. The map of the island is accompanied by a rigorous representation of direct and inferred age relationships between lavas and scoria cones of different eruptions using a novel type of age correlation diagram. The time period covered by the flow-by-flow mapping includes both the final stages of growth of an older shield volcano (Monte Amarelo volcano) prior to its collapse and the subsequent growth of a new volcano (Cha das Caldeiras volcano). The latter forms a thick infill and summit cone within the Monte Amarelo collapse scar together with partial covering of the outer flanks of the Monte Amarelo volcano with a veneer of younger lavas and scoria cones. The erupted rocks are compositionally varied (ankaramitic nephelinites, basanites, tephrites) and often highly porphyritic. Petrographic criteria were therefore used to aid field mapping, define lithostratigraphic units and demonstrate systematic changes in compositions of erupted magmas through time. Some of these changes, particularly eruptions of ankaramitic magmas, coincide with similar sequences of volcano-structural changes that have occurred prior to the Monte Amarelo collapse and again during the Holocene (beginning around 11 000 years before present; Foeken et al, 2009). The flow-by-flow mapping approach has allowed reconstruction and comparison of the sequences of these structural changes, and thus provides insights into the inferred progressive destabilization of the eastern flank of Fogo during the Holocene, as well as into wide variations in eruption and resurfacing rates that have occurred on decade to century timescales in more recent times. Foeken, J.P.T., Day, S.J. & Stuart, F.M. (2009) Cosmogenic 3He exposure dating of the Quaternary basalts from Fogo, Cape Verdes: Implications for rift zone and magmatic reorganization. Quaternary Geology 4 (2009) 37 - 49.

Day, S. J.

2011-12-01

180

Education: Solomons Winner in Lengthy Plagiarism Trial.  

ERIC Educational Resources Information Center

Reports the outcome of a plagiarism suit against organic chemistry professor T. W. Graham Solomons by two emeritus professors at New York University. The ruling of not guilty leaves the way open for Solomons' counterclaim that he lost sales of the book because of the suit. (Author/SA)

Stinson, Steve

1980-01-01

181

Joseph H. Solomon Department of Mechanical Engineering,  

E-print Network

Joseph H. Solomon Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, seals can track hydro- dynamic trails (Dehnhardt et al. 2001) and rats can distinguish small differences (for a review, see Solomon and Hartmann (2008)), and several recent studies have specifically addressed

Hartmann, Mitra J. Z.

182

Internal structure of the western flank of the Cumbre Vieja volcano, La Palma, Canary Islands, from land  

E-print Network

Palma, Canary Islands, from land magnetotelluric imaging X. Garcia1,2 and A. G. Jones1 Received 9 March wasting is a natural part of the evolution of volcanic islands, where deformation and indications of flank on the island of La Palma (Canary Islands) provides an ideal setting to address fundamental questions about

Jones, Alan G.

183

An investigation of the distribution of eruptive products on the shield volcanoes of the western Galapagos Islands using remotely sensed data  

NASA Technical Reports Server (NTRS)

Recent volcanic activity in the Galapagos Islands is concentrated on the two westernmost islands, Isla Isabela and Isla Fernandina. Difficult access has thus far prevented comprehensive geological field studies, so we examine the potential of remotely sensed data as a means of studying volcanic processes in the region. Volcan Wolf is used as an example of the analysis of SPOT HRV-1 data undertaken for each volcano. Landsat TM data are analyzed in an attempt to construct a relative age sequence for the recent eruptive activity on Isla Fernandina. No systematic variation in the surface reflectance of lava flows as a function of age could be detected with these data. Thus it was not possible to complete a study of the temporal distribution of volcanic activity.

Munro, Duncan C.; Rowland, Scott K.; Mouginis-Mark, Peter J.; Wilson, Lionel; Oviedo-Perez, Victor-Hugo

1991-01-01

184

2006 Volcanic Activity in Alaska, Kamchatka, and the Kurile Islands: Summary of Events and Response of the Alaska Volcano Observatory  

USGS Publications Warehouse

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.

Neal, Christina A.; McGimsey, Robert G.; Dixon, James P.; Manevich, Alexander; Rybin, Alexander

2008-01-01

185

Vedder, J.G., and Bruns, T.R., editors, 1989, Geology and offshore resources of Pacific island arc mo Islands and  

E-print Network

Vedder, J.G., and Bruns, T.R., editors, 1989, Geology and offshore resources of Pacific island arc mo Islands and Bougainville, Papua New Guinea Regions: Houston, Texas, Circum-Pacific Council SOLOMONS TROUGH, SOLOMON ISLANDS-REVIEW AND NEW FINDINGS T.R. Bruns, J.G. Vedder, and A.K. Cooper U

186

Response of the shallow aquifer of the volcano-hydrothermal system during the recent crises at Vulcano Island (Aeolian Archipelago, Italy)  

NASA Astrophysics Data System (ADS)

The shallow thermal aquifer at Vulcano Island is strongly affected by deep volcanic fluids. The most significant variations were observed during the 1989-1996 crisis due to a large input of steam and acidic gases from depth. Besides chemical variations related to the input of deep fluids, the record of the water-table elevation at monitored wells has provided remarkable insights into the pressure conditions of the volcano-hydrothermal system. After the pressure drop due to the extensive vaporization of the hydrothermal aquifer, occurred after 1993, the volcano-hydrothermal system has been re-pressurized since 2001, probably because of the contribution of volatiles from the hydrothermal-magmatic source. The increase in fluid pressure may have caused reopening of fractures (which had self-seated during the previous period of cooling) and the onset of a phase of higher vapor output in the fumarole field later in 2004. The fracture opening would have promoted further vapor separation from the deep fluid reservoir (hypothesized at 0.5-1.5 km depth) and finally the drainage of S-rich fluids into the shallow thermal aquifer (found out at few tens of meters of depth). The monitoring of both the water chemistry and the water-table elevation provides insights into the eventual pressurization of the volcano-hydrothermal system that precedes the fracture opening and the extensive drainage of deep fluids. The findings of this study could represent crucial information about the stability of the volcano edifice, and lead to reliable techniques for determining the risk of or even predicting phreatic explosions.

Capasso, Giorgio; Federico, Cinzia; Madonia, Paolo; Paonita, Antonio

2014-03-01

187

A new model for the growth of basaltic shields based on deformation of Fernandina volcano, Galápagos Islands  

USGS Publications Warehouse

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.

Bagnardi, Marco; Amelung, Falk; Poland, Michael P.

2013-01-01

188

Researchers Discover Underwater Volcano-within-a-Volcano (PR 05-089)  

NSF Publications Database

... an active underwater volcano near the Samoan Island chain. During a research cruise to study the ... indication that this volcano existed. When sound beams were directed into the crater, they measured ...

189

Volcanic-ash hazard to aviation during the 2003-2004 eruptive activity of Anatahan volcano, Commonwealth of the Northern Mariana Islands  

USGS Publications Warehouse

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; thereafter, the maximum plume height decreased and during the rest of the eruption usually did not exceed ???5 km (???17,000 ft), which lessened the potential hazard to aircraft at higher cruise altitudes. Drifting ash clouds commonly extended hundreds of kilometers from the volcano, occasionally as far west as the Philippines. Over the course of the eruptive activity in 2003-2004, the VAAC issued 323 advisories (168 with graphical depictions of ash clouds) for Anatahan, serving as a reliable source of ash-cloud information for aviation-related meteorological offices and air carriers. With a record of frequent eruptions in the CNMI, continued satellite and in situ real-time geophysical monitoring is needed at Anatahan and other Marianas volcanoes so that potential hazards to aviation from any future eruptive activity can be quickly and correctly assessed. ?? 2005 Elsevier B.V. All rights reserved.

Guffanti, M.; Ewert, J. W.; Gallina, G. M.; Bluth, G. J. S.; Swanson, G. L.

2005-01-01

190

Volcanoes Galore!  

NSDL National Science Digital Library

Here, you can check out videos and links to lots of nifty volcano stuff. Have fun! This is completely unrelated...but check it out anywho. sweet periodic table! Alaska Volcano Observatory Earthquakes and Volcanoes Check this one out for info on history\\'s most distructive volcano. Exploring Pompeii and Vesuvius Exploring the Environment: Volcanoes This will give you lots of background on how Volcanoes work, what the major parts are, and how they erupt. How Volcanoes Work A quick video on how to take a lava sample...hot! Lava Sampling on Kilauea Volcano, Hawai i A volcano in antartica? ...

Syracuse, Mr.

2008-06-11

191

Long-term explosion records from two erupting submarine volcanoes in the Mariana and Tonga island-arcs  

NASA Astrophysics Data System (ADS)

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 ?Pa @ 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 from West Mata, a near-arc boninite volcano discovered actively erupting the month before. An ROV cruise in May 2009 deployed two short-term, high-frequency (1024 Hz) hydrophones within 50 m of the Hades volcanic vent (1208 m deep). Both the long-term and in situ hydrophones detected explosive activity as well as both mono- and polychromatic volcanic tremor throughout their records. ROV video shows the acoustic signals are from violent degassing bursts from within lava extruding at the Hades vent (summit of West Mata). The explosions exhibit both short (10s of sec) and long (2-10 min) duration modes of cyclic activity. Many explosion signals also show harmonic tremor within their codas indicative of resonance from within the volcanic edifice. Frequently the explosion records are overlapped by monochromatic tremor from a narrow band within a range from 20-100 Hz. The source of this resonance is not yet clear (although not man-made) and is possibly from a nearby, unseen vent or magma movement within the volcanic edifice.

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

192

New K-Ar ages for calculating end-of-shield extrusion rates at West Maui volcano, Hawaiian island chain  

USGS Publications Warehouse

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.

Sherrod, D. R.; Murai, T.; Tagami, T.

2007-01-01

193

EarthScope: Activity at Augustine Volcano  

NSDL National Science Digital Library

This bulletin provides information on the recent eruptive activity of Augustine Volcano in Alaska. Topics include some history of the volcano, its geologic setting as part of the Aleutian island arc, and earthquake locations as indicators of magma movement. The bulletin is also accompanied by a 360-degree rotation around the volcano and background information on the EarthScope Project.

2011-06-03

194

Man Against Volcano: The Eruption on Heimaey,  

E-print Network

Man Against Volcano: The Eruption on Heimaey, Vestmannaeyjar, Iceland This booklet was originally published in 1976 under the title "Man Against Volcano:The Eruption on Heimaey, Vestmann Islands, Iceland:Town of Vestmannaeyjar with Helgafell in the right back- ground (photo courtesy of Sólarfilma). #12;Man Against Volcano

Ingólfsson, �lafur

195

Hydrogeology of Stromboli volcano, Aeolian Islands (Italy) from the interpretation of resistivity tomograms, self-potential, soil temperature and soil CO2 concentration measurements  

NASA Astrophysics Data System (ADS)

To gain a better insight of the hydrogeology and the location of the main tectonic faults of Stromboli volcano in Italy, we collected electrical resistivity measurements, soil CO2 concentrations, temperature and self-potential measurements along two profiles. These two profiles started at the village of Ginostra in the southwest part of the island. The first profile (4.8 km in length) ended up at the village of Scari in the north east part of the volcano and the second one (3.5 km in length) at Forgia Vecchia beach, in the eastern part of the island. These data were used to provide insights regarding the position of shallow aquifers and the extension of the hydrothermal system. This large-scale study is complemented by two high-resolution studies, one at the Pizzo area (near the active vents) and one at Rina Grande where flank collapse areas can be observed. The Pizzo corresponds to one of the main degassing structure of the hydrothermal system. The main degassing area is localized along a higher permeability area corresponding to the head of the gliding plane of the Rina Grande sector collapse. We found that the self-potential data reveal the position of an aquifer above the villages of Scari and San Vincenzo. We provide an estimate of the depth of this aquifer from these data. The lateral extension of the hydrothermal system (resistivity ˜15-60 ohm m) is broader than anticipated extending in the direction of the villages of Scari and San Vincenzo (in agreement with temperature data recorded in shallow wells). The lateral extension of the hydrothermal system reaches the lower third of the Rina Grande sector collapse area in the eastern part of the island. The hydrothermal body in this area is blocked by an old collapse boundary. This position of the hydrothermal body is consistent with low values of the magnetization (<2.5 A m-1) from previously published work. The presence of the hydrothermal body below Rina Grande raises questions about the mechanical stability of this flank of the edifice.

Revil, A.; Finizola, A.; Ricci, T.; Delcher, E.; Peltier, A.; Barde-Cabusson, S.; Avard, G.; Bailly, T.; Bennati, L.; Byrdina, S.; Colonge, J.; di Gangi, F.; Douillet, G.; Lupi, M.; Letort, J.; Tsang Hin Sun, E.

2011-09-01

196

Space-geodetic evidence for multiple magma reservoirs and subvolcanic lateral intrusions at Fernandina Volcano, Galápagos Islands  

NASA Astrophysics Data System (ADS)

Using Interferometric Synthetic Aperture Radar (InSAR) measurements of the surface deformation at Fernandina Volcano, Galápagos (Ecuador), acquired between January 2003 and September 2010, we study the structure and the dynamics of the shallow magmatic system of the volcano. Through the analysis of spatial and temporal variations of the measured line-of-sight displacement we identify multiple sources of deformation beneath the summit and the southern flank. At least two sources are considered to represent permanent zones of magma storage given their persistent or recurrent activity. Elastic deformation models indicate the presence of a flat-topped magma reservoir at ˜1.1 km below sea level and an oblate-spheroid cavity at ˜4.9 km b.s.l. The two reservoirs are hydraulically connected. This inferred structure of the shallow storage system is in agreement with previous geodetic studies and previous petrological analysis of both subaerial and submarine lavas. The almost eight-year-long observation interval provides for the first time geodetic evidence for two subvolcanic lateral intrusions from the central storage system (in December 2006 and August 2007). Subvolcanic lateral intrusions could provide the explanation for enigmatic volcanic events at Fernandina such as the rapid uplift at Punta Espinoza in 1927 and the 1968 caldera collapse without significant eruption.

Bagnardi, Marco; Amelung, Falk

2012-10-01

197

Time variability of low-temperature fumaroles at Stromboli island (Italy) and its application to volcano monitoring  

NASA Astrophysics Data System (ADS)

The constant and mild activity of Stromboli volcano (Italy) is occasionally interrupted by effusive events and/or more energetic explosions, referred to as major explosions and paroxysms, which are potentially dangerous for the human community. Although several premonitory signals for effusive phases have been identified, precursors of major explosions and paroxysms still remain poorly understood. With the aim of contributing to the identification of possible precursors of energetic events, this work discusses soil temperature data acquired in low-temperature fumaroles at Stromboli in the period 2006-2010. Data analysis revealed that short-term anomalies recorded in the thermal signal are potentially useful in predicting state changes of the volcano. In particular, sudden changes in fumarole temperatures and their hourly gradients were observed from several days to a few hours prior to fracturing and paroxysmal events, heralded by peculiar waveforms of the recorded signals. The qualitative interpretation is supported by a quantitative, theoretical treatment that uses circuit theory to explain the time dependence of the short-period temperature variations, showing a good agreement between theoretical and observational data.

Madonia, Paolo; Fiordilino, Emilio

2013-12-01

198

How changes in pore pressure affect fluid circulation in volcanoes: three examples from Vulcano Island, Mt. Etna and Mt Vesuvius (Italy)  

NASA Astrophysics Data System (ADS)

Fluids circulating in volcanic edifices are attracting increasing interest from scientists, mostly because their role in triggering flank instability, phreatic explosions, and eruptions has been documented in several cases worldwide [Newhall et al. 2001, Thomas et al. 2004]. Fluid pore pressure can change as an effect of either external (meteoric recharge, variation of the stress field), or endogenous causes (e.g. internal pressurization of magmatic volatiles and hydrothermal systems). The reciprocal roles of tectonics and magmatic/hydrothermal activity are still under investigation [Gottsman et al. 2007, Roeloffs et al. 2003]. We discuss the results of decennial data records collected in the aquifers of Mt Etna, Vulcano Island and Mt Vesuvius, and get insights on the role of tectonics and volcanic activity on the observed variations of water level and chemical composition. In Vulcano Island, the shallow thermal aquifer is deeply concerned by deep volcanic fluids. The most significant variations were observed during the 1988-96 crisis, due to the large input of steam and acidic gases from depth. In addition, the record of the water table elevation provided remarkable insights on the pressure of the volcano-hydrothermal system, which can be envisaged as the cause for the onset of the phase of higher vapor output in the fumarolic field in late 2004. On Mt. Vesuvius, the geochemical behavior of the aquifer appears strictly controlled by the input of volcanic gases and variations in the stress field. These latter, which were responsible for the seismic crisis of 1999, and the almost simultaneous increased input of CO2-rich vapor, significantly affected water chemistry and temperature, until 2006. The recent observations of low salinity, temperature, and dissolved carbon contents in groundwater provide strong evidence for reduced pressure in the volcano-hydrothermal system. The record of water chemistry available on Mt. Etna since 1994 shows coeval changes in almost all monitored sites, ascribed to the variable contribution over time of waters with different temperature and composition. In addition, the dissolved CO2 content is chiefly affected by the input of volcanic CO2. Given the intense dynamics of the volcano, with frequent eruptions and periodic inflation-deflation phases, as well as the uneven deformation of the edifice, changes in water chemistry can be attributed, at least in part, to stress-related changes in pore pressure. Changes of pore pressure and micro-fracturation are controlling fluid movement (water and gases) within the volcano, producing part of the observed geochemical variations. The accurate modeling of the proposed process of fluid pressure increase, fracturing, and drainage of deep fluids will benefit of a multidisciplinary approach, able to clarify the cause-effect relationship and critical conditions. Newhall CG et al. 2001. J. Geol. Soc. Philipp., 56, 69-84. Thomas ME et al. 2004. Terra Nova, 16, 312-317. Gottsmann J. et al. 2007. GRL 34, L07307. Roeloffs E. et al. 2003. JVGR 127, 269-303.

Federico, C.; Madonia, P.; Capasso, G.; D'Alessandro, W.; Bellomo, S.; Brusca, L.; Cusano, P.; Longo, M.; Paonita, A.; Petrosino, S.

2013-05-01

199

Explosive activity of the summit cone of Piton de la Fournaise volcano (La Réunion island): A historical and geological review  

NASA Astrophysics Data System (ADS)

Summit explosive activity and collapses that form pit craters and calderas represent major volcanic hazards on a dominantly effusive, frequently active volcano like Piton de la Fournaise. Only three summit collapse events (1986, 2002, 2007) have been recorded since the foundation of the Piton de la Fournaise volcano observatory (OVPF) in 1979, and two of them (1986 and 2007) were associated with weak phreatic activity. At Piton de la Fournaise, the normal explosive activity consists of short-lived and mild (< 20 m-high) lava fountains, which quickly evolve into strombolian activity during the eruptions. Based on comprehensive literature review and high-resolution image analysis of surface outcrops and summit caldera walls, we reconstructed the time distribution of recent explosive events (phreatomagmatic; phreatic) and their link with summit collapses and lateral (flank) effusive eruptions. In historical time (post-1640 CE), we recognise two main clusters of explosive events. Frequent and violent phreatomagmatic to phreatic explosions occurred during the oldest cluster (1708-1878) and alternated with long-lasting periods (years to decades) of summit effusive activity. In contrast, scarce, and on average, weak explosions occurred during the youngest cluster (1897-2012), when discrete and short-lived (< 6 months) effusive eruptions represent the main eruptive dynamics. Historical summit collapses (pit craters and caldera), all localised at the top of the summit cone, were related to voluminous lateral eruptions and were followed by a significant decrease in eruptive rate. However, magma draining during lateral eruptions was not systematically associated with summit collapses or explosions. The long-lasting occurrence of magma at very shallow depth below the volcano summit, followed by a rapid lateral drainage, apparently represents a critical condition favouring magma-groundwater interaction to produce explosive activity. The prehistoric growth of the Piton de la Fournaise summit cone results chiefly from long-lasting to continuous activity, centred below its western side (Bory crater containing lava lakes). High lava fountains, long-lasting effusive activity, lava lakes, ash plumes and block ejections were common types of eruptive dynamics in the historical past, between 1640 and 1878. In this perspective, short-lived, small volume eruptions and long pauses, up to six years, during the last century of activity of Piton de la Fournaise can be considered as a lull, despite the high frequency of eruption (1 eruption/9 months on average). Temporal and spatial variations in recurrence rate and eruptive dynamics of basaltic volcanism, such as those recognised at Piton de la Fournaise, should be considered in the formulation of hazard assessments and in the interpretation of precursory patterns.

Michon, Laurent; Di Muro, Andrea; Villeneuve, Nicolas; Saint-Marc, Cécile; Fadda, Pierluigi; Manta, Fabio

2013-08-01

200

Tsunami deposits related to flank collapse in oceanic volcanoes: The Agaete Valley evidence, Gran Canaria, Canary Islands  

Microsoft Academic Search

Enigmatic marine conglomerates are attached at 41–188 m asl to the walls of the valley of Agaete, on the northwest coast of Gran Canaria (Canary Islands). They are formed by heterogeneous, angular to rounded heterometric volcanic clasts (roundness and maximal size decreasing with altitude), and fossils (rhodolites and marine shells), never found in growth position and often broken. The deposits

Francisco J. Pérez-Torrado; Raphaël Paris; María C. Cabrera; Jean-Luc Schneider; Patrick Wassmer; Juan-Carlos Carracedo; Ángel Rodríguez-Santana; Francisco Santana

2006-01-01

201

Mount St. Helens and Kilauea volcanoes  

SciTech Connect

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.

Barrat, J. (Smithsonian Institution, Washington, DC (USA))

1989-01-01

202

Solomon Yan Google's PageRank Algorithm  

E-print Network

Math 547 Solomon Yan Google's PageRank Algorithm Applications of Linear Algebra Introduction Google; compared to other search engines, Google provides the most relevant results first. As a search engine, Google needs to be able to accomplish two specific tasks. First of all, it needs to access and remember

Marzuola, Jeremy

203

Design Primer for Reed-Solomon Encoders  

NASA Technical Reports Server (NTRS)

Design and operation of Reed-Solomon (RS) encoders discussed in document prepared as instruction manual for computer designers and others in dataprocessing field. Conventional and Berlekamp architectures compared. Engineers who equip computer memory chips with burst-error and dropout detection and correction find report especially useful.

Perlman, M.; Lee, J. J.

1985-01-01

204

Barren Island Volcano (NE Indian Ocean): Island-Arc High-Alumina Basalts to Andesites Caused by Troctolite Disaggregation and Plagioclase Accumulation  

NASA Astrophysics Data System (ADS)

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 along the same subduction zone that carries the Indo-Australian Plate northeastward beneath the southeast corner of the Eurasian Plate. The island has a diameter of only 3 km and rises to 355 m above sea level. Three eruptive episodes are known in historical time. A cinder cone formed near the center of the island in 1787, within remnants of a pre-historical caldera 2 km in diameter and open to the west. Eruptions continued intermittently until 1832. Two other episodes occurred more recently, during March to October 1991 and December 1994 to May 1995. Each eruption included strombolian and fire-fountain activity at the central and flank vents of the cinder cone and the westward flow of block lavas through the caldera breach until they cascaded into the sea. This investigation is based on 28 samples collected from Barren Island by researchers from the Geological Survey of India during expeditions to the island prompted by the eruptions of 1991 and 1994-1995. The samples include 18 lavas, 5 scoriae, and 5 bulk ashes that can be divided into 4 age groups: pre-1787 (n=6), 1787-1832 (n=4), 1991 (n=8), and 1994-1995 (n=10). Whole-rock compositions range from 50.7 to 59.8 wt.% SiO2, and thus span the range from basalt to andesite. All samples contain phenocrysts and microphenocrysts of olivine (plus spinel), plagioclase, and clinopyroxene. A notable textural feature in many samples from all age groups is the presence of abundant (to 40 vol.%), large (to 4 mm) phenocrysts of plagioclase. These have clear tabular cores of homogeneous highly calcic composition at An90-95, surrounded by normally zoned mantles, 10-150 microns thick, that range down to An48. Plagioclase phenocryst abundances vary with whole-rock SiO2 (negatively) and Al2O3 (positively) contents. All samples with >20 vol.% plagioclase phenocrysts have >19 wt.% Al2O3 and <53 wt.% SiO2. Samples rich in plagioclase phenocrysts also have slight positive Eu anomalies. All evidence points to generation of these high-Al basalts by accumulation of calcic plagioclase during dissagregation of troctolitic xenoliths, which are found within historical lavas and scoriae. We suppose that a magmatic mush or plutonic mass of troctolite at depth beneath Barren Island is the source of this contamination. These high-Al basalts, at least, are not magmatic compositions. Six Barren Island samples were also analyzed for Sr, Nd, and Pb isotopic compositions, which show a crude trend toward more enriched values with time: overall ranges are 87Sr/86Sr = 0.7038-0.7041, ? Nd = 4.1-6.8, 206Pb/204Pb = 18.20-18.29. Trapped glass inclusions in olivine phenocrysts were analyzed for volatile contents by Fourier-transform infrared spectroscopy and electron microprobe. The highest values for total H2O are 2.6 and 3.1 wt.% from two 1991 inclusions. Carbon species were not detected, as is typical for subduction-zone glasses. Sulfur contents ranged 0.08-0.20 wt.% SO3, and Cl contents ranged 0.14-0.21 wt.%, reflecting the elevated Cl values that characterize subduction-related glasses worldwide, in contrast with those from mid-ocean ridges or hot spots.

Luhr, J. F.; Haldar, D.

2003-12-01

205

Volcano Live  

NSDL National Science Digital Library

The volocanologist John Seach provides the latest volcano news and information on volcanoes all across the world. The website provides fun hands-on activities, tutorials in volcano safety and volcanology, and a glossary. Students can discover the geography of many areas of the world and how it impacts the likelihood of volcanic eruptions. Users can find links to numerous volcano cameras and maps. The amazing images of volcanoes from Seach's expeditions are a great addition to this informative site.

206

Eruptive activity of the summit cone of Piton de la Fournaise volcano (La Réunion island): a historical and geological review.  

NASA Astrophysics Data System (ADS)

Summit explosive activity and collapses represent major volcanic hazards on a dominantly effusive and frequently active volcano like Piton de la Fournaise. Only three summit collapse events (1986, 2002 and 2007) have been recorded since the foundation of the Piton de la Fournaise volcano observatory (OVPF) in 1979 and two of them (1986 and 2007) were associated with weak phreatic activity. Except during these three events, most eruptions consist in short short-lived (< 3 hours) and mild (< 20 m-high) lava fountains quickly evolving into strombolian activity. Based on a comprehensive literature review and a high-resolution image analysis of surface outcrops and summit caldera walls, we reconstructed the time distribution of recent explosive events and their link with summit collapses and lateral effusive eruptions. In historical times (post-1640 AD), we recognize two main clusters of explosive events. Frequent and violent phreatomagmatic to phreatic explosions occurred during the oldest cluster (1708-1878) characterized by long-lasting summit effusive activity. On the contrary, weak and scarce explosions occurred during the youngest cluster (1897-2012), in which discrete and often short-lived effusive eruptions represent the main eruptive dynamics. Historical summit collapses (pit craters to caldera), all localized at the top of the summit cone, were related to voluminous lateral eruptions and were followed by a significant decrease in eruptive rate. However, many lateral eruptions were not associated with summit collapses or explosions. The long-lasting occurrence of magma at very shallow depth represents thus a critical condition to produce summit explosive activity. The pre-historic building of Piton de la Fournaise summit cone results from a long-lasting to continuous activity centered below its western side (Bory crater/lava lakes). Frequent and large lava fountains and long-lasting lava lakes represented an important dynamics in this recent past. In this perspective, the last century of activity of Piton de la Fournaise can be considered as a lull, in spite of its high frequency (1 eruption / 9 months on average).

Di Muro, Andrea; Michon, Laurent; Villeneuve, Nicolas; Saint-Marc, Cecile

2013-04-01

207

Flank instability of Stromboli volcano (Aeolian Islands, Southern Italy): Integration of GB-InSAR and geomorphological observations  

NASA Astrophysics Data System (ADS)

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.

Intrieri, Emanuele; Di Traglia, Federico; Del Ventisette, Chiara; Gigli, Giovanni; Mugnai, Francesco; Luzi, Guido; Casagli, Nicola

2013-11-01

208

Fumarole-Supported Islands of Biodiversity within a Hyperarid, High-Elevation Landscape on Socompa Volcano, Puna de Atacama, Andes? †  

PubMed Central

Fumarolic activity supports the growth of mat-like photoautotrophic communities near the summit (at 6,051 m) of Socompa Volcano in the arid core of the Andes mountains. These communities are isolated within a barren, high-elevation landscape where sparse vascular plants extend to only 4,600 m. Here, we combine biogeochemical and molecular-phylogenetic approaches to characterize the bacterial and eucaryotic assemblages associated with fumarolic and nonfumarolic grounds on Socompa. Small-subunit rRNA genes were PCR amplified, cloned, and sequenced from two fumarolic soil samples and two reference soil samples, including the volcanic debris that covers most of the mountain. The nonfumarolic, dry, volcanic soil was similar in nutrient status to the most extreme Antarctic Dry Valley or Atacama Desert soils, hosted relatively limited microbial communities dominated by Actinobacteria and Fungi, and contained no photoautotrophs. In contrast, modest fumarolic inputs were associated with elevated soil moisture and nutrient levels, the presence of chlorophyll a, and 13C-rich soil organic carbon. Moreover, this soil hosted diverse photoautotroph-dominated assemblages that contained novel lineages and exhibited structure and composition comparable to those of a wetland near the base of Socompa (3,661-m elevation). Fumarole-associated eucaryotes were particularly diverse, with an abundance of green algal lineages and a novel clade of microarthropods. Our data suggest that volcanic degassing of water and 13C-rich CO2 sustains fumarole-associated primary producers, leading to a complex microbial ecosystem within this otherwise barren landscape. Finally, we found that human activities have likely impacted the fumarolic soils and that fumarole-supported photoautotrophic communities may be exceptionally sensitive to anthropogenic disturbance. PMID:19074608

Costello, Elizabeth K.; Halloy, Stephan R. P.; Reed, Sasha C.; Sowell, Preston; Schmidt, Steven K.

2009-01-01

209

Fumarole-supported islands of biodiversity within a hyperarid, high-elevation landscape on Socompa Volcano, Puna de Atacama, Andes.  

PubMed

Fumarolic activity supports the growth of mat-like photoautotrophic communities near the summit (at 6,051 m) of Socompa Volcano in the arid core of the Andes mountains. These communities are isolated within a barren, high-elevation landscape where sparse vascular plants extend to only 4,600 m. Here, we combine biogeochemical and molecular-phylogenetic approaches to characterize the bacterial and eucaryotic assemblages associated with fumarolic and nonfumarolic grounds on Socompa. Small-subunit rRNA genes were PCR amplified, cloned, and sequenced from two fumarolic soil samples and two reference soil samples, including the volcanic debris that covers most of the mountain. The nonfumarolic, dry, volcanic soil was similar in nutrient status to the most extreme Antarctic Dry Valley or Atacama Desert soils, hosted relatively limited microbial communities dominated by Actinobacteria and Fungi, and contained no photoautotrophs. In contrast, modest fumarolic inputs were associated with elevated soil moisture and nutrient levels, the presence of chlorophyll a, and (13)C-rich soil organic carbon. Moreover, this soil hosted diverse photoautotroph-dominated assemblages that contained novel lineages and exhibited structure and composition comparable to those of a wetland near the base of Socompa (3,661-m elevation). Fumarole-associated eucaryotes were particularly diverse, with an abundance of green algal lineages and a novel clade of microarthropods. Our data suggest that volcanic degassing of water and (13)C-rich CO(2) sustains fumarole-associated primary producers, leading to a complex microbial ecosystem within this otherwise barren landscape. Finally, we found that human activities have likely impacted the fumarolic soils and that fumarole-supported photoautotrophic communities may be exceptionally sensitive to anthropogenic disturbance. PMID:19074608

Costello, Elizabeth K; Halloy, Stephan R P; Reed, Sasha C; Sowell, Preston; Schmidt, Steven K

2009-02-01

210

Evidence of flank failure deposit reactivation in a shield volcano. A favorable context for deep-seated landslide activation (La Réunion Island)  

NASA Astrophysics Data System (ADS)

Giant flank failures are recurrent features of shield volcanoes, and their deposits (i.e. breccia), constitute a significant volume in a volcanic edifice. On La Réunion Island, the growth and development of Piton des Neiges volcano has been punctuated by several flank failure episodes. One of these failures is a deep-seated landslide (>200 Mm3) occurring nowadays in Grand Ilet, a plateau inhabited by 1 000 people in the cirque of Salazie, on the northern flank of Piton des Neiges. Here we present the results of a multidisciplinary study (structural geology and field mapping, GNSS monitoring, borehole logging) performed to characterize the geological structure the Grand Ilet landslide, and identify the instability factors that control this category of destabilization. Basic breccia deposits, up to 160 meters thick, constitute the main geological formation of the unstable mass. This breccia are cut by the headwall scar of the landslide, and covered by lava flows, indicating a minimum age of 200 kyr for the destabilization that produced the deposits. The breccia is consolidated out of the landslide area. The NE toe of the landslide is evidenced by an important compressional deformation of the base of the breccia, and striated surfaces in this deformed volume indicate a NE-direction of transport. In this deformed bulge, a clay-rich layer at the base of the breccia has been identified as the main slip plane. Using a video inspection of drill casings on three exploration boreholes, we reconstructed the 3D geometry of the slip plane at the base of the breccia. This reconstruction shows that the landslide plane has an average dip of 6° toward the NE. The displacement monitoring network shows that the unstable mass has a 5.5 km2 extension, with a variable azimuth of movement direction (N140° for the SW sector, and N45° for the NE sector). The planimetric displacements velocities range between 2 cm/year in the inner part of the unstable mass to 52 cm/year at the landslide toe. The dip of displacement vectors vary from 34° ± 9 uphill to 7° ± 2 downhill near the landslide toe. This displacement field, the topography and the drill casings inspection show that secondary shear zones are located inside the landslide mass, characterized by a lower deformation rate than the basal shear zone. However heterogeneous is the deformation, it more important at the base of the breccia (locally in the clay layer). Ultimately, our study suggests that the main slip plane has localized at the base of the breccia despite its induration. Thus we conclude that the Grand Ilet landslide is in fact a present-day reactivation of an old destabilization.

Belle, Pierre; Aunay, Bertrand; Famin, Vincent; Join, Jean-Lambert

2014-05-01

211

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)

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.

Yeguas, A. García.; Almendros, J.; Abella, R.; Ibáñez, J. M.

2011-02-01

212

Under the volcano: phylogeography and evolution of the cave-dwelling Palmorchestia hypogaea (Amphipoda, Crustacea) at La Palma (Canary Islands)  

PubMed Central

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 estimations assuming a non-correlated relaxed clock with a normal prior distribution of the age of La Palma, together with the lack of association of habitat type with ancestral and recent haplotypes, suggest that their adaptation to cave life is relatively ancient. Conclusion The data gathered here provide evidence for multiple invasions of the volcanic cave systems that have acted as refuges. A re-evaluation of the taxonomic status of the extant species of Palmorchestia is needed, as the division of the two species by habitat and ecology is unnatural. The information obtained here, and that from previous studies on hypogean fauna, shows the importance of factors such as the uncoupling of morphological and genetic evolution, the role of climatic change and regressive evolution as key processes in leading to subterranean biodiversity. PMID:18234125

Villacorta, Carlos; Jaume, Damia; Oromi, Pedro; Juan, Carlos

2008-01-01

213

Savage Earth: Out of the Inferno - Volcanoes  

NSDL National Science Digital Library

This article, entitled Mountains of Fire, describes the relationship between the types of volcanic activity and plate movement and the connection between types of volcanoes and how they erupt. The article is supported by a video of an erupting volcano, a photograph of an eruption and an animation depicting pyroclastic flow and the formation of a composite volcano. It is also supported by three sidebars, called Volcanoes of North America, Montserrat: An Island Under Siege, and Volcanoes on other Planets. These sidebars also have videos or photographs to enhance their message.

214

Cascades Volcano Observatory - Learn About Volcanoes: Frequently Asked Volcano Questions  

NSDL National Science Digital Library

This page provides the answers to frequently asked questions about volcanoes. It is created by the United States Geological Survey. Topics addressed include: What Is A Volcano? Why Do Volcanoes Occur? How Do Volcanoes Erupt? Where Do Volcanoes Occur? When Will A Volcano Erupt? How Hot Is A Volcano? Can Lava Be Diverted? Do Volcanoes Affect Weather? What Types of Volcanoes are There? Which Eruptions Were The Deadliest? 20th Century Volcanic Eruptions and Their Impact. About 60 additional questions with answers are available under MORE FAQ's -Volcano Questions and Answers, and includes some sections on volcanoes of the western United States. Other links to volcano information are also available.

215

Decade Volcanoes  

NSDL National Science Digital Library

In the 1990s, the International Association of Volcanology and Chemistry of the Earth's Interior started the Decade Volcano Project. As part of their work, they designated sixteen volcanoes particularly worthy of study "because of their explosive histories and close proximity to human populations." The group recently teamed up with National Geographic to create a guide to these volcanoes via this interactive map. Navigating through the map, visitors can learn about Mount Rainier, Colima, Galeras, Santorini, and other prominent volcanoes. For each volcano, there's a brief sketch that gives the date of its last eruption, its elevation, nearby population centers, and a photograph.

216

Erupting Volcano Mount Etna  

NASA Technical Reports Server (NTRS)

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.

2002-01-01

217

Distribution, 14C chronology, and paleomagnetism of latest Pleistocene and Holocene lava flows at Haleakala?? volcano, Island of Maui, Hawai'i: A revision of lava flow hazard zones  

USGS Publications Warehouse

New mapping and 60 new radiocarbon ages define the age and distribution of latest Pleistocene and Holocene (past 13,000 years) lava flows at Haleakala?? volcano, Island of Maui. Paleomagnetic directions were determined for 118 sites, of which 89 are in lava flows younger than 13,000 years. The paleomagnetic data, in conjunction with a reference paleosecular variation (PSV) curve for the Hawaiian Islands, are combined with our knowledge of age limitations based on stratigraphic control to refine age estimates for some of the undated lava flows. The resulting volumetric rate calculations indicate that within analytical error, the extrusion rate has remained nearly constant during the past 13,000 years, in the range 0.05-0.15 km3/kyr, only about half the long-term rate required to produce the postshield strata emplaced in the past ???1 Myr. Haleakala??'s eruptive frequency is similar to that of Huall??ai volcano on the Island of Hawai'i, but its lava flows cover substantially less area per unit time. The reduced rates of lava coverage indicate a lower volcanic hazard than in similar zones at Huala??lai.

Sherrod, D.R.; Hagstrum, J.T.; McGeehin, J.P.; Champion, D.E.; Trusdell, F.A.

2006-01-01

218

The Solomon Sea eddy activity from a 1/36° regional model  

NASA Astrophysics Data System (ADS)

In the South West Pacific, the Solomon Sea exhibits the highest levels of eddy kinetic energy but relatively little is known about the eddy activity in this region. This Sea is directly influenced by a monsoonal regime and ENSO variability, and occupies a strategical location as the Western Boundary Currents exiting it are known to feed the warm pool and to be the principal sources of the Equatorial UnderCurrent. During their transit in the Solomon Sea, meso-scale eddies are suspected to notably interact and influence these water masses. The goal of this study is to give an exhaustive description of this eddy activity. A dual approach, based both on altimetric data and high resolution modeling, has then been chosen for this purpose. First, an algorithm is applied on nearly 20 years of 1/3° x 1/3° gridded SLA maps (provided by the AVISO project). This allows eddies to be automatically detected and tracked, thus providing some basic eddy properties. The preliminary results show that two main and distinct types of eddies are detected. Eddies in the north-eastern part shows a variability associated with the mean structure, while those in the southern part are associated with generation/propagation processes. However, the resolution of the AVISO dataset is not very well suited to observe fine structures and to match with the numerous islands bordering the Solomon Sea. For this reason, we will confront these observations with the outputs of a 1/36° resolution realistic model of the Solomon Sea. The high resolution numerical model (1/36°) indeed permits to reproduce very fine scale features, such as eddies and filaments. 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. Validation is realized by comparison with AVISO observations and available in situ data. In preparing the future wide-swath altimetric SWOT mission that is expected to provide observations of small-scale sea level variability, spectral analysis is performed from the 1/36° resolution realistic model in order to characterize the finer scale signals in the Solomon sea region. The preliminary SSH spectral analysis shows a k-4 slope, in good agreement with the suface quasigeostrophic (SQG) turbulence theory. Keywords: Solomon Sea; meso-scale activity; eddy detection, tracking and properties; wavenumber spectrum.

Djath, Bughsin; Babonneix, Antoine; Gourdeau, Lionel; Marin, Frédéric; Verron, Jacques

2013-04-01

219

Plant diversity changes during the postglacial in East Asia: insights from Forest Refugia on Halla Volcano, Jeju Island.  

PubMed

Understanding how past climate changes affected biodiversity is a key issue in contemporary ecology and conservation biology. These diversity changes are, however, difficult to reconstruct from paleoecological sources alone, because macrofossil and pollen records do not provide complete information about species assemblages. Ecologists therefore use information from modern analogues of past communities in order to get a better understanding of past diversity changes. Here we compare plant diversity, species traits and environment between late-glacial Abies, early-Holocene Quercus, and mid-Holocene warm-temperate Carpinus forest refugia on Jeju Island, Korea in order to provide insights into postglacial changes associated with their replacement. Based on detailed study of relict communities, we propose that the late-glacial open-canopy conifer forests in southern part of Korean Peninsula were rich in vascular plants, in particular of heliophilous herbs, whose dramatic decline was caused by the early Holocene invasion of dwarf bamboo into the understory of Quercus forests, followed by mid-Holocene expansion of strongly shading trees such as maple and hornbeam. This diversity loss was partly compensated in the Carpinus forests by an increase in shade-tolerant evergreen trees, shrubs and lianas. However, the pool of these species is much smaller than that of light-demanding herbs, and hence the total species richness is lower, both locally and in the whole area of the Carpinus and Quercus forests. The strongly shading tree species dominating in the hornbeam forests have higher leaf tissue N and P concentrations and smaller leaf dry matter content, which enhances litter decomposition and nutrient cycling and in turn favored the selection of highly competitive species in the shrub layer. This further reduced available light and caused almost complete disappearance of understory herbs, including dwarf bamboo. PMID:22438890

Dolezal, Jiri; Altman, Jan; Kopecky, Martin; Cerny, Tomas; Janecek, Stepan; Bartos, Michael; Petrik, Petr; Srutek, Miroslav; Leps, Jan; Song, Jong-Suk

2012-01-01

220

Appreciating Unity in Diversity: An Interview with Andrew Solomon  

ERIC Educational Resources Information Center

The theme of the AMS 2014 Annual Conference is "Unity in Diversity," a concept that also describes the work of conference keynote speaker Andrew Solomon. Solomon is a writer and lecturer on psychology and politics; winner of the National Book Award; and an activist for LGBT [lesbian, gay, bisexual, and transgender] rights, mental health,…

Peters, Dane L.

2014-01-01

221

Eruption Rate Control On Morphology And Structure Of Submarine Monogenetic Volcanoes - Insights From Sumersible Dives Off Maui And Hawaii Islands  

NASA Astrophysics Data System (ADS)

This paper presents the results of submersible dives off Hawaii Islands during four research cruises (R/V Kairei-ROV Kaiko 1998 and 2001, R/V Yokosuka-DSV Shinkai 1999 and 2002) by the Japan Marine Science and Technology Center. Morphologies and structures of submarine volcanic edifices were observed during dives on the Hana Ridge, submarine extension of Haleakala rift zone of East Maui and the south rift zone of Loihi Seamount. Three types of volcanic edifices are recognized: 1) Conical seamount with a small summit and steep slopes [Clague et al., 2000]; 2) Flat-topped cone [Clague et al., 2000] or terrace [Smith et al., 2002] with a wide, flat summit compared to the relative height; 3) Lobate terrace with a hemi-circular lobate outline with a smaller areal ratio of the summit to the base than flat-topped cones. These volcanic edifices are morphologically classified into two groups: Group A (flat-topped cones and lobate terraces) shows a positive correlation of an areal ratio of summit/base with slope. Group B (conical seamounts) has a low areal ratio of summit/base and a positive correlation between a volume and slope. ROV Kaiko and DSV Shinkai dives were carried out on 6 conical seamounts, 5 flat-topped cones and 3 lobate terraces. Conical seamounts with moderate slopes have aprons of elongate pillows and a summit crater filled by lobate sheet flows, which gradually change into elongate pahoehoe flows downslope. Steep cones are surrounded by talus slopes of pillow rubble with elongate pillows sporadically exposed between pillow clasts. Embedded pillow lobes are all elongate downslope, indicating that fragmentation took place while pillows were flowing. Under a very low extrusion rate, flowing lava congealed on the steep slope in a short distance from the source and collapsed into rubble that formed the lower part of the cone. Flat-topped cones have elongate pillows on moderate slopes, and pahoehoe and lobate sheet flows interbedded with pillows on gentle slopes. Flat summits are overlain by lobate sheets but do not have any collapse pits. Successive change in flow morphology from lobate sheets on the summit through pahoehoe sheets into elongate pillows downslope indicates that lava quietly spilt over the crater rim flowed as elongate pillows on steep slopes. Because lobate sheets are present interbedded with pillows in the lower slope, several eruptive episodes with higher extrusion rates of lava were repeated to form the flat-topped cones. Lobate terraces have similar constituents as flat-topped cones but collapse pits on the summit. Lava channels are present both on the bottom of the pits and on the aprons of the terraces, through which lava was rapidly expelled. Lobate terraces are more like a single large inflated sheet flow grown on a gentle ridge that broke out channeled lava at the final stage of growth.

Umino, S.

2003-12-01

222

Living with Volcanoes: Year Eleven Teaching Resource Unit.  

ERIC Educational Resources Information Center

Presents a unit on volcanoes and experiences with volcanoes that helps students develop geography skills. Focuses on four volcanoes: (1) Rangitoto Island; (2) Lake Pupuke; (3) Mount Smart; and (4) One Tree Hill. Includes an answer sheet and resources to use with the unit. (CMK)

Le Heron, Kiri; Andrews, Jill; Hooks, Stacey; Larnder, Michele; Le Heron, Richard

2000-01-01

223

How Are Islands Formed?  

NSDL National Science Digital Library

This lesson provides students with information about how islands are formed, including a basic knowledge of plate tectonics. Using the islands of Hawaii as an example, students learn about the earth processes that cause the formation of islands over time, including volcanoes and hot spots.

2001-01-01

224

Volcano Types  

NSDL National Science Digital Library

This site lists the basic types of volcanoes: scoria cone, shield volcano, and stratovolcano. Each is described in terms of shape, composition, and eruption type, and links are available to additional information. Subordinate types listed include fissure eruptions, spatter cones, hornitos, and hydrovolcanic eruptions. The site also explains when a volcano is considered active, dormant, or extinct. In addition, generic features such as vent, central vent, edifice, magma chamber, parasitic cones, and fumaroles are listed and described.

Camp, Victor

225

Paleogene stratigraphy of the Solomons Island, Maryland corehole  

USGS Publications Warehouse

Purge and trap capillary gas chromatography/mass spectrometry is a rapid, precise, accurate method for determining volatile organic compounds in samples of surface water and ground water. The method can be used to determine 59 selected compounds, including chlorofluorohydrocarbons, aromatic hydrocarbons, and halogenated hydrocarbons. The volatile organic compounds are removed from the sample matrix by actively purging the sample with helium. The volatile organic compounds are collected onto a sorbant trap, thermally desorbed, separated by a Megabore gas chromatographic capillary column, ionized by electron impact, and determined by a full-scan quadrupole mass spectrometer. Compound identification is confirmed by the gas chromatographic retention time and by the resultant mass spectrum. Unknown compounds detected in a sample can be tentatively identified by comparing the unknown mass spectrum to reference spectra in the mass-spectra computer-data system library compiled by the National Institute of Standards and Technology. Method detection limits for the selected compounds range from 0.05 to 0.2 microgram per liter. Recoveries for the majority of the selected compounds ranged from 80 to 120 percent, with relative standard deviations of less than 10 percent.

Gibson, Thomas G.; Bybell, Laurel M.

1994-01-01

226

Syn and posteruptive hazards of maar–diatreme volcanoes  

Microsoft Academic Search

Maar–diatreme volcanoes represent the second most common volcano type on continents and islands. This study presents a first review of syn- and posteruptive volcanic and related hazards and intends to stimulate future research in this field. Maar–diatreme volcanoes are phreatomagmatic monogenetic volcanoes. They may erupt explosively for days to 15 years. Above the preeruptive surface a relatively flat tephra ring forms.

Volker Lorenz

2007-01-01

227

Volcano spacing and plate rigidity  

SciTech Connect

In-plane stresses, which accompany the flexural deformation of the lithosphere under the load adjacent volcanoes, may govern the spacing of volcanoes in hotspot provinces. Specifically, compressive stresses in the vicinity of a volcano prevent new upwelling in this area, forcing a new volcano to develop at a minimum distance that is equal to the distance in which the radial stresses change from compressional to tensile (the inflection point). If a volcano is modeled as a point load on a thin elastic plate, then the distance to the inflection point is proportional to the thickness of the plate to the power of 3/4. Compilation of volcano spacing in seven volcanic groups in East Africa and seven volcanic groups of oceanic hotspots shows significant correlation with the elastic thickness of the plate and matches the calculated distance to the inflection point. In contrast, volcano spacing in island arcs and over subduction zones is fairly uniform and is much larger than predicted by the distance to the inflection point, reflecting differences in the geometry of the source and the upwelling areas.

Brink, U. (Stanford Univ., California (USA))

1991-04-01

228

Evolution of elastic properties and acoustic emission, during uniaxial loading of rocks, from the Fogo Volcano in the island of Sao Miguel, Azores; Preliminary results.  

NASA Astrophysics Data System (ADS)

A Computerized Uniaxial Press working up to 250 kN was installed in the middle 2011 in the Laboratory of Microseismic Monitoring of ISEL. The system is able to record continuous time, pressure and axial strain (1 µm resolution) at 1s sampling rate. The loading platens were designed to integrate acoustic emission (AE) transducers. Signals are acquired and processed through an 8-channel ESG Hyperion Ultrasonic Monitoring System (10 MSPS, 14/16-bit ADC). The first experiments, presented here, were applied to a set of rock samples from the Fogo, an active central volcano in the island of Sao Miguel. Two different volcanic rock types were studied: a fine grained alkali basaltic rock with a porphyritic texture, a porosity of 4.5% and bulk density of 2700 kg m-3 (sample #3); and a benmoreitic rock with a trachytic texture, a porosity of 8.1 %, and bulk density of 2400 kg m-3 (sample #4). Cores from sample #3 were subjected to continuous increasing pressure, until failure. They show a uniaxial compressive strength (UCS) spanning from 60 to 85 MPa and a stress-strain curve with two phases: a first one with relative low Young's Module (YM) followed by a second phase were the YM increases roughly 3 times. The stress transition value occurs broadly in a stress level 50% of the UCS. The AE produced in the process is almost negligible until the YM transition stress level and increases after that. Important pulses of high AE rate occur, (> 100 s-1), associated with the occurrence and propagation of fractures, which are always parallel to the principal stress, showing an evident pattern of tensile fractures. About 20s before the failure, very important deformation rate is observed, the YM strongly decrease, and continuous AE events, with low rate, usually <50 s-1. The failure is accompanied with a sudden rise of AE events with rate > 200 s-1. Cycling stress experiences were also performed showing reversible stress-strain relation for axial pressure below the YM transition level, and important hysteresis for axial pressure above that level. The associated AE events show a characteristic Kaiser effect pattern. Cores from sample #4 undergo the same continuous increasing stress process, but failure is attained at a considerable lower pressure of 20-25 MPa. The stress-strain curves show an almost linear relation, but approaching the stress level of failure, the YM decreases. The AE events are constant but with a reduced rate until the decrease of the YM, when a significant rise in the AE occurs, achieving emission rates greater that 200 s-1. The fracture shows a characteristic shear pattern. Differences in stress-strain behavior, fracture mode and AE rates are associated with the very different structure of the rocks, once the basaltic sample is very fine grained with some very scattered and almost spherical vesicles or voids, while the benmoreitic core shows high values of porosity in a structure with vesicles and voids with very irregular shapes. Work supported by FCT, Portugal, projet FreeRock, PTDC/CTE-GIX/100687/2008

Moreira, M.; Wallenstein, N.

2012-04-01

229

A Versatile Time-Domain Reed-Solomon Decoder  

Microsoft Academic Search

A versatile Reed-Solomon (RS) decoder structure based on the time-domain decoding algorithm (transform decoding without transforms) is developed. The algorithm is restructured, and a method is given to decode any RS code generated by any generator polynomial. The main advantage of the decoder structure is its versatility, that is, it can be programmed to decode any Reed-Solomon code defined in

Yousef R. Shayan; Tho Le-ngoc; Vijay K. Bhargava

1990-01-01

230

Volcano Preparedness  

MedlinePLUS

... your local emergency officials. Mudflows Mudflows are powerful “rivers” of mud that can move 20 to 40 ... cannot see the volcano during an eruption. Avoid river valleys and low lying areas. Trying to watch ...

231

Dante's Volcano  

NASA Technical Reports Server (NTRS)

This video contains two segments: one a 0:01:50 spot and the other a 0:08:21 feature. Dante 2, an eight-legged walking machine, is shown during field trials as it explores the inner depths of an active volcano at Mount Spurr, Alaska. A NASA sponsored team at Carnegie Mellon University built Dante to withstand earth's harshest conditions, to deliver a science payload to the interior of a volcano, and to report on its journey to the floor of a volcano. Remotely controlled from 80-miles away, the robot explored the inner depths of the volcano and information from onboard video cameras and sensors was relayed via satellite to scientists in Anchorage. There, using a computer generated image, controllers tracked the robot's movement. Ultimately the robot team hopes to apply the technology to future planetary missions.

1994-01-01

232

Cascade Volcanoes  

USGS Multimedia Gallery

The volcanoes from closest to farthest are Mt. Washington, Three Fingered Jack, Mt. Jefferson. This picture is taken from Middle Sister looking north in the Cascade Range, Three Sisters Wilderness Area, Deschutes National Forest, Oregon....

2009-12-08

233

Mahukona: The missing Hawaiian volcano  

SciTech Connect

New bathymetric and geochemical data indicate that a seamount west of the island of Hawaii, Mahukona, is a Hawaiian shield volcano. Mahukona has weakly alkalic lavas that are geochemically distinct. They have high {sup 3}He/{sup 4}He ratios (12-21 times atmosphere), and high H{sub 2}O and Cl contents, which are indicative of the early state of development of Hawaiian volcanoes. The He and Sr isotopic values for Mahukona lavas are intermediate between those for lavas from Loihi and Manuna Loa volcanoes and may be indicative of a temporal evolution of Hawaiian magmas. Mahukona volcano became extinct at about 500 ka, perhaps before reaching sea level. It fills the previously assumed gap in the parallel chains of volcanoes forming the southern segment of the Hawaiian hotspot chain. The paired sequence of volcanoes was probably caused by the bifurcation of the Hawaiian mantle plume during its ascent, creating two primary areas of melting 30 to 40 km apart that have persisted for at least the past 4 m.y.

Garcia, M.O.; Muenow, D.W. (Univ. of Hawaii, Honolulu (USA)); Kurz, M.D. (Woods Hole Oceanographic Institution, MA (USA))

1990-11-01

234

An investigation of the distribution of eruptive products on the shield volcanoes of the western Galapagos Islands using remotely sensed data  

Microsoft Academic Search

Recent volcanic activity in the Galapagos Islands is concentrated on the two westernmost islands, Isla Isabela and Isla Fernandina. Difficult access has thus far prevented comprehensive geological field studies, so we examine the potential of remotely sensed data as a means of studying volcanic processes in the region. Volcan Wolf is used as an example of the analysis of SPOT

Duncan C. Munro; Scott K. Rowland; Peter J. Mouginis-Mark; Lionel Wilson; Victor-Hugo Oviedo-Perez

1991-01-01

235

Mass Wasting in the Western Galapagos Islands  

E-print Network

Oceanic island volcanoes such as those in the Hawaiian, Canary and Galapagos Islands are known to become unstable, causing failures of the subaerial and submarine slopes of the volcanic edifices. These mass wasting events appear to be the primary...

Hall, Hillary

2012-10-19

236

Dengue virus type 3, South Pacific Islands, 2013.  

PubMed

After an 18-year absence, dengue virus serotype 3 reemerged in the South Pacific Islands in 2013. Outbreaks in western (Solomon Islands) and eastern (French Polynesia) regions were caused by different genotypes. This finding suggested that immunity against dengue virus serotype, rather than virus genotype, was the principal determinant of reemergence. PMID:24856252

Cao-Lormeau, Van-Mai; Roche, Claudine; Musso, Didier; Mallet, Henri-Pierre; Dalipanda, Tenneth; Dofai, Alfred; Nogareda, Francisco; Nilles, Eric J; Aaskov, John

2014-06-01

237

Dengue Virus Type 3, South Pacific Islands, 2013  

PubMed Central

After an 18-year absence, dengue virus serotype 3 reemerged in the South Pacific Islands in 2013. Outbreaks in western (Solomon Islands) and eastern (French Polynesia) regions were caused by different genotypes. This finding suggested that immunity against dengue virus serotype, rather than virus genotype, was the principal determinant of reemergence. PMID:24856252

Roche, Claudine; Musso, Didier; Mallet, Henri-Pierre; Dalipanda, Tenneth; Dofai, Alfred; Nogareda, Francisco; Nilles, Eric J.; Aaskov, John

2014-01-01

238

Cascade Range Volcanoes: North to South  

NSDL National Science Digital Library

This page lists Cascades Range volcanoes of British Columbia, Washington State, Oregon, and California. The user can click on the volcano name to get information on the volcano and its vicinity including Current Activity; Background and Information; Current Hazards Report; Visit a Volcano; Maps, Graphics, and Images; Items of Interest; and Useful Links. The volcanoes include: Garibaldi Lake Volcano, Meager Mountain, and Mount Garibaldi in British Columbia; Mount Baker, Glacier Peak, Mount Rainier, Mount St. Helens, and Mount Adams in Washington State: Mount Hood, Mount Jefferson, Three-Fingered Jack, Mount Washington, Belknap Shield Volcano, Three Sisters (North, Middle, South), Broken Top, Mount Bachelor, Pilot Butte, Lava Butte, Newberry Caldera, Diamond Peak, Mount Bailey, Mount Thielsen, Crater Lake, Mount Mazama, Wizard Island, and Mount McLoughlin in Oregon:, and Lava Beds, Medicine Lake Volcano, Glass Mountain (Medicine Lake, California), Black Butte, Mount Shasta, and Lassen Peak in California. Links are provided to more general pages on volcanoes in the three states and in Canada.

239

Exploiting the cannibalistic traits of Reed-Solomon codes  

NASA Technical Reports Server (NTRS)

In Reed-Solomon codes and all other maximum distance separable codes, there is an intrinsic relationship between the size of the symbols in a codeword and the length of the codeword. Increasing the number of symbols in a codeword to improve the efficiency of the coding system thus requires using a larger set of symbols. However, long Reed-Solomon codes are difficult to implement and many communications or storage systems cannot easily accommodate an increased symbol size, e.g., M-ary frequency shift keying (FSK) and photon-counting pulse-position modulation demand a fixed symbol size. A technique for sharing redundancy among many different Reed-Solomon codewords to achieve the efficiency attainable in long Reed-Solomon codes without increasing the symbol size is described. Techniques both for calculating the performance of these new codes and for determining their encoder and decoder complexities is presented. These complexities are usually found to be substantially lower than conventional Reed-Solomon codes of similar performance.

Collins, O.

1993-01-01

240

Lahar Hazards at Concepción volcano, Nicaragua  

USGS Publications Warehouse

Concepción is one of Nicaragua’s highest and most active volcanoes. The symmetrical cone occupies the northeastern half of a dumbbell shaped island called Isla Ometepa. The dormant volcano, Maderas, occupies the southwest half of the island. A narrow isthmus connects Concepción and Maderas volcanoes. Concepción volcano towers more than 1600 m above Lake Nicaragua and is within 5 to 10 km of several small towns situated on its aprons at or near the shoreline. These towns have a combined population of nearly 5,000. The volcano has frequently produced debris flows (watery flows of mud, rock, and debris—also known as lahars when they occur on a volcano) that could inundate these nearby populated areas. Concepción volcano has erupted more than 25 times in the last 120 years. Its first recorded activity was in AD 1883. Eruptions in the past century, most of which have originated from a small summit crater, comprise moderate explosions, ash that falls out of eruption plumes (called tephra), and occasional lava flows. Near the summit area, there are accumulations of rock that were emplaced hot (pyroclastic deposits), most of which were hot enough to stick together during deposition (a process called welding). These pyroclastic rocks are rather weak, and tend to break apart easily. The loose volcanic rock remobilizes during heavy rain to form lahars. Volcanic explosions have produced blankets of tephra that are distributed downwind, which on Isla Ometepe is mostly to the west. Older deposits at the west end of the island that are up to 1 m thick indicate larger explosive events have happened at Concepción volcano in prehistoric time. Like pyroclastic-flow deposits, loose tephra on the steep slopes of the volcano provides source material that heavy rainstorms and earthquakes can mobilize to trigger debris flow.

Vallance, J.W.; Schilling, S.P.; Devoli, G.; Howell, M.M.

2001-01-01

241

Map of water table in Solomon River valley, Waconda Lake to Solomon, north-central Kansas, May 1980  

USGS Publications Warehouse

A map of the water table in the Solomon River valley from Waconda Lake to Solomon presents current (1980) data on water levels in the unconsolidated deposits. The Solomon River, which originates in western Kansas, flows southeastward from Waconda Lake to its confluence with the Smoky Hill River at Solomon. In the study area, its valley is incised into consolidated rocks that are composed mostly of shale and limestone. The unconsolidated deposits in the valley underlie the flood plain and the terrace. The alluvial deposits generally consist of gravel and sand, grading upward to sand and silt, with clay lenses interbedded throughout. Thickness of the deposits may be as much as 70 feet. Ground water in the unconsolidated deposits is a principal source of supply for domestic, stock, and irrigation use. Water-table contours indicate that ground water moves from the alluvial deposits to the stream. Thus, the Solomon River gains in flow through most of the reach. Water-level measurements for this study were made during the spring of 1980, prior to the irrigation season. (USGS)

Reed, Thomas B.

1983-01-01

242

Radiocarbon dates for lava flows from northeast rift zone of Mauna Loa Volcano, Hilo 7 1/2 minute quadrangle, Island of Hawaii  

USGS Publications Warehouse

Twenty-eight 14C analyses are reported for carbonized roots and other plant material collected from beneath 15 prehistoric lava flows erupted from the northeast rift zone (NERZ) of Mauna Loa Volcano (ML). The new 14C dates establish ages for 13 previously undated lava flows, and correct or add to information previously reported. Limiting ages on other flows that lie either above or below the dated flows are also established. These dates help to unravel the eruptive history of ML's NERZ. -from Authors

Buchanan-Banks, J. M.; Lockwood, J. P.; Rubin, M.

1989-01-01

243

Volcano-Tectonic Deformation at Taal Volcano, Philippines  

NASA Astrophysics Data System (ADS)

Taal Volcano, located in southern Luzon, Philippines, is an unusual, tholeiitic volcano situated within a calc-alkaline arc. It is one of the most active volcanic centers in the Philippines, with some 33 historic volcanic eruptions over the past four centuries. Volcanism at Taal is at least partly tectonically controlled, suggested by its location at the intersection of regional fault structures and by the location and shape of both Taal's caldera and Volcano Island. The alignment of modern eruption centers, are controlled by regional and local structures. Here, we review geomorphic and geodetic observations that constrain both tectonic and volcanic deformation in the vicinity of Taal volcano. We use GPS measurements from a 52-station GPS network measured from 1996 - 2001 to investigate overall plate interaction and microplate (intra-arc) deformation. The velocity field indicates that the majority of the Philippine Sea - Eurasia plate convergence is taking place west of Luzon, presumably largely by subduction at the Manila trench. A relatively small fraction of the convergence appears to be taking place within Luzon or across the East Luzon trough. The major intra-arc deformation is accommodated by strike-slip motion along the Philippine Fault, ranging from 25-40 mm/yr left-lateral slip. Detailed measurements in southern Luzon also indicate significant intra-arc deformation west of the Philippine Fault. GPS measurements in southwestern Luzon indicate significant motion within the arc, which could be explained by 11-13 mm/yr of left-lateral shear along the "Macolod Corridor", within which Taal Volcano resides. A dense network of continuous single- and dual-frequency GPS receivers at Taal Volcano, Philippines reveals highly time-variable deformation behavior, similar to that observed at other large calderas. While the caldera has been relatively quiescent for the past 2-3 years, previous deformation includes two major phases of intra-caldera deformation, including two phases of inflation and deflation in 1998-2000. The February-November 2000 period of inflation was characterized by approximately 120 mm of uplift of the center of Volcano Island relative to the northern caldera rim, at average rates up to 216 mm/yr. The source of deflation in 1999 was modeled as a contractional Mogi point source centered at 4.2 km depth beneath Volcano Island; the source of inflation in 2000 was modeled as a dilatational Mogi point source centered at 5.2 km depth beneath Volcano Island. The locations of the two sources are indistinguishable within the 95% confidence estimates. Modeling using a running four-month time window from June 1999-March 2001 reveals little evidence for source migration. We find marginal evidence for an elongate source whose long axis is oriented NW-SE, paralleling the caldera-controlling fault system. We suggest that the two periods of inflation observed at Taal represent episodic intrusions of magma into a shallow reservoir centered beneath Volcano Island whose position is controlled at least in part by regional tectonic structures.

Hamburger, M. W.; Galgana, G.; Corpuz, E.; Bartel, B.

2004-12-01

244

VLSI single-chip (255,223) Reed-Solomon encoder with interleaver  

NASA Technical Reports Server (NTRS)

The invention relates to a concatenated Reed-Solomon/convolutional encoding system consisting of a Reed-Solomon outer code and a convolutional inner code for downlink telemetry in space missions, and more particularly to a Reed-Solomon encoder with programmable interleaving of the information symbols and code correction symbols to combat error bursts in the Viterbi decoder.

Hsu, In-Shek (inventor); Deutsch, Leslie J. (inventor); Truong, Trieu-Kie (inventor); Reed, Irving S. (inventor)

1990-01-01

245

Composite tuff ring\\/cone complexes in Jeju Island, Korea: possible consequences of substrate collapse and vent migration  

Microsoft Academic Search

Hydromagmatic volcanoes (tuff rings and tuff cones) in Jeju Island, Korea, are divided into Holocene volcanoes that were constructed upon rigid, plateau-forming lavas and early to middle Pleistocene volcanoes that underlie the lavas and were constructed upon fragile, unconsolidated sediments. The older volcanoes are distinguished from the Holocene volcanoes in that the former have irregular morphologies. The irregular morphologies resulted

Young Kwan Sohn; Ki Hwa Park

2005-01-01

246

Cascades Volcano Observatory  

NSDL National Science Digital Library

The Cascades Volcano Observatory of the U.S. Geological Survey has announced a WWW server offering information on volcanically-induced geologic and hydrologic hazards as well as images of volcanoes and volcanic phenomena. Includes links to ther components of the USGS Volcano Hazards Program such as the Alaska and Hawaii Volcano Observatory and the international Volcano Disaster Assistance Program.

247

Internet Geography: Volcanoes  

NSDL National Science Digital Library

This site is part of GeoNet Internet Geography, a resource for pre-collegiate British geography students and their instructors. This page focuses on various aspects of volcanoes, including the main features of a volcano, types of volcanoes, the Ring of Fire, locations of volcanoes, volcanic flows, and case studies about specific volcanoes.

248

Mapping the magma conduit for the Shinmoe-dake volcano  

NASA Astrophysics Data System (ADS)

Near the southern end of Kyushu, the most southerly of Japan's major islands, a complex of more than 20 small volcanoes together form the Kirishima volcanoes. In January 2011, approximately 20 million cubic meters of material spewed from one of the volcanoes, Shinmoe-dake. Before this most recent activity, Shinmoe-dake had previously erupted in 2010, 1991, 1962, and 1959, with the 2011 eruption being the biggest.

Schultz, Colin

2014-05-01

249

Mud Volcanoes Formation And Occurrence  

NASA Astrophysics Data System (ADS)

Mud volcanoes are natural phenomena, which occur throughout the globe. They are found at a greater or lesser scale in Azerbaijan, Turkmenistan, Georgia, on the Kerch and Taman peninsulas, on Sakhalin Island, in West Kuban, Italy, Romania, Iran, Pakistan, India, Burma, China, Japan, Indonesia, Malaysia, New Zealand, Mexico, Colombia, Trinidad and Tobago, Venezuela and Ecuador. Mud volcanoes are most well-developed in Eastern Azerbaijan, where more than 30% of all the volcanoes in the world are concentrated. More than 300 mud volcanoes have already been recognized here onshore or offshore, 220 of which lie within an area of 16,000 km2. Many of these mud volcanoes are particularly large (up to 400 m high). The volcanoes of the South Caspian form permanent or temporary islands, and numerous submarine banks. Many hypotheses have been developed regarding the origin of mud volcanoes. Some of those hypotheses will be examined in the present paper. Model of spontaneous excitation-decompaction (proposed by Ivanov and Guliev, 1988, 2002). It is supposed that one of major factors of the movement of sedimentary masses and formation of hydrocarbon deposits are phase transitions in sedimentary basin. At phase transitions there are abnormal changes of physical and chemical parameters of rocks. Abnormal (high and negative) pressure takes place. This process is called as excitation of the underground environment with periodicity from several tens to several hundreds, or thousand years. The relationship between mud volcanism and the generation of hydrocarbons, particularly methane, is considered to be a critical factor in mud volcano formation. At high flow rates the gas and sediment develops into a pseudo-liquid state and as flow increases the mass reaches the "so-called hover velocity" where mass transport begins. The mass of fluid moves as a quasi-uniform viscous mass through the sediment pile in a piston like manner until expelled from the surface as a "catastrophic eruption". Model of buoyancy drive (by Brown, 1990). Brown's basic hypothesis is similar to Ivanov and Guliev and may be summarized briefly as follows: -in situations where rapid sedimentation is occurring mud may be driven to the surface by buoyancy forces due to bulk density contrasts between mud and overlying sediment cover. Such density contrasts may be simply the result of compaction -disequilibrium, but more importantly may be related to gas expansion when fluids are transported to shallower depths with lower pressure and temperature conditions. Synthetic model had been proposed by I.Lerche, E.Bagirov, I.Guliyev (1997). The model includes the following studies: The starting point of the mud volcanoes begins with the formation of a zone of decompaction as a consequence of a high rate of gas generation. The mud body starts to rise under buoyancy. The excess pressure inside the mud intrusion is less than in surrounding formation. As a result, fluid flow toward the body of mud volcanoes. The body of the mud volcanoes then grows, increasing the buoyancy forces, with further drive the mud. If the rate of gas generation more thôn gas flow, causing exsolving of gas to free-phase gas. If there are open faults and fractures which cross the body of mud volcanoes, then gas and mud can penetrate through the faults, and so from gryphons and salses on the surface. A mud volcanoes can be consider as a huge accumulation of gas, where as the oil is concentrated on the flanks of the mud body.

Guliyev, I. S.

2007-12-01

250

The active lava flows of Kilauea volcano, Hawaii  

Microsoft Academic Search

Kilauea volcano in the Hawaiian Islands, Pacific Ocean, is the world’s most active volcano. Observations of active lava flows\\u000a of Kilauea have a great relevance to studies of older, extinct volcanic systems, such as those found in India.

Hetu Sheth

2003-01-01

251

Eruptions of Hawaiian Volcanoes: Past, Present, and Future  

NSDL National Science Digital Library

The origin of the Hawaiian Islands, recorded eruptions, and eruption patterns are discussed in this United States Geological Survey (USGS) publication. The on-line book also covers volcano monitoring and research, landforms and structures, hazards and benefits, and a discussion of Loihi, Hawaii's newest volcano.

Tilling, Robert; Wright, Thomas

252

The Earthscope Plate Boundary Observatory Akutan Alaskan Volcano Network Installation  

Microsoft Academic Search

During June and July of 2005, the Plate Boundary Observatory (PBO) installed eight permanent GPS stations on Akutan Volcano, in the central Aleutian Islands of Alaska. PBO worked closely with the Alaska Volcano Observatory and the Magmatic Systems Site Selection working group to install stations with a spatial distribution to monitor and detect both short and long term volcanic deformation

B. Pauk; M. Jackson; D. Mencin; J. Power; W. Gallaher; A. Basset; K. Kore; Z. Hargraves; T. Peterson

2005-01-01

253

2011 volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory  

USGS Publications Warehouse

The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest at or near three separate volcanic centers in Alaska during 2011. The year was highlighted by the unrest and eruption of Cleveland Volcano in the central Aleutian Islands. AVO annual summaries no longer report on activity at Russian volcanoes.

McGimsey, Robert G.; Maharrey, J. Zebulon; Neal, Christina A.

2014-01-01

254

Newberry Volcano--Central Oregon's Sleeping Giant U.S. Department of the Interior  

E-print Network

Newberry Volcano--Central Oregon's Sleeping Giant U.S. Department of the Interior U.S. Geological Survey USGS Fact Sheet 2011-3145 2011 the largest volcano in the Cascades volcanic arc and covers an area the size of Rhode Island. Unlike familiar cone-shaped Cascades volcanoes, Newberry was built into the shape

Torgersen, Christian

255

Space-geodetic evidence for multiple magma reservoirs and subvolcanic lateral intrusions at Fernandina Volcano,  

E-print Network

Aperture Radar (InSAR) measurements of the surface deformation at Fernandina Volcano, Gal�pagos (Ecuador at Fernandina Volcano, Gal�pagos Islands Marco Bagnardi1 and Falk Amelung1 Received 23 May 2012; revised 12 magmatic system of the volcano. Through the analysis of spatial and temporal variations of the measured

Amelung, Falk

256

REDUCING THE RISK FROM VOLCANO HAZARDS Lahars of Mount Pinatubo, Philippines  

E-print Network

Pinatubo on the island of Luzon in the Philippines, the volcano had been dormant for 500 years, allowingREDUCING THE RISK FROM VOLCANO HAZARDS O Lahars of Mount Pinatubo, Philippines n June 15, 1991 in the Philippines (Clark Air Base), were built on the broad gentle slopes surrounding the volcano. When Pinatubo

Torgersen, Christian

257

What Are Volcano Hazards?  

MedlinePLUS

... Hawaii, California, Oregon, and Washington. Volcanoes produce a wide variety of hazards that can kill people and ... a volcano is not erupting. Volcanoes produce a wide variety of natural hazards that can kill people ...

258

Aquifers and groundwater within active shield volcanoes. Evolution of conceptual models in the Piton de la Fournaise volcano  

Microsoft Academic Search

The uncertainty regarding hydrogeological models that have been proposed for describing active volcanoes results from the difficulty of prospecting deep groundwater bodies. In the case of the Piton de la Fournaise volcano located in Reunion Island, recent geophysical exploration using deep electromagnetic (EM) prospecting tools has provided new geostructural and hydrogeological information. This paper introduces yet a new hydrogeological model,

Jean-Lambert Join; Jean-Luc Folio; Bernard Robineau

2005-01-01

259

Deformation Associated with 1995, 2005 and 2009 Eruptions at Fernandina Volcano, Galápagos, Observed by Satellite Radar Interferometry  

Microsoft Academic Search

Fernandina Island is part of the Galápagos Islands, a volcanic archipelago located on the Nazca plate about 1000 km west of Ecuador. With a diameter of about 30 km, the island consists of a single volcano with a maximum elevation of 1470 meters and a central caldera nearly 1000 meters deep. Fernandina is considered one of the most active volcanoes

M. Bagnardi; F. Amelung; S. Baker

2009-01-01

260

Fast transform decoding of nonsystematic Reed-Solomon codes  

NASA Technical Reports Server (NTRS)

A Reed-Solomon (RS) code is considered to be a special case of a redundant residue polynomial (RRP) code, and a fast transform decoding algorithm to correct both errors and erasures is presented. This decoding scheme is an improvement of the decoding algorithm for the RRP code suggested by Shiozaki and Nishida, and can be realized readily on very large scale integration chips.

Truong, T. K.; Cheung, K.-M.; Reed, I. S.; Shiozaki, A.

1989-01-01

261

New Perspectives on Ancient Mars Sean C. Solomon,1  

E-print Network

and semimajor axes similar to those of Earth and Venus, but any final body at the orbit of Mars tends to be too in the vicinity of Mars's orbit (8). Alternatively, Mars may be a surviving embryo that escaped either ac- cretionNew Perspectives on Ancient Mars Sean C. Solomon,1 * Oded Aharonson,2 Jonathan M. Aurnou,3 W. Bruce

Head III, James William

262

"SQUID Susceptometry Imaging of Magnetic Nanoparticles" Solomon Diamond  

E-print Network

"SQUID Susceptometry Imaging of Magnetic Nanoparticles" Solomon Diamond 2010-2011 We have completed for synchronized recording of the SQUID system, encoder, and a fluxgate magnetometer and also developed software for magnetic field simulation and data analysis. We have demonstrated experimentally that the SQUID system can

Shepherd, Simon

263

METAPLECTIC ICE BEN BRUBAKER, DANIEL BUMP, GAUTAM CHINTA, SOLOMON FRIEDBERG,  

E-print Network

;2 B. BRUBAKER, D. BUMP, G. CHINTA, S. FRIEDBERG, AND P. E. GUNNELLS the second in terms of a functionMETAPLECTIC ICE BEN BRUBAKER, DANIEL BUMP, GAUTAM CHINTA, SOLOMON FRIEDBERG, AND PAUL E. GUNNELLS amenable to proof using the Yang-Baxter equation. We give two examples of this: first, the equivalence

Bump, Daniel

264

Diffusion MRI of Complex Tissue Structure David Solomon Tuch  

E-print Network

Diffusion MRI of Complex Tissue Structure by David Solomon Tuch B.A., Physics, University-MIT Division of Health Sciences and Technology #12;#12;Diffusion MRI of Complex Tissue Structure by David resonance diffusion imaging provides an exquisitely sensitive probe of tis- sue microstructure. Owing

Duncan, James S.

265

Fraser Island Lady Elliot Island  

E-print Network

BRISBANE Fraser Island Lady Elliot Island Lady Musgrave Island Wilson Island Heron Island Great Hinchinbrook Island Lizard Island Double Island Green Island Fitzroy Island North and South Stradbroke Islands

Wang, Yan

266

First cross-correlated measurements of magma dynamics and degassing during a dyke eruption at Piton de la Fournaise hot spot volcano, Reunion island  

NASA Astrophysics Data System (ADS)

Piton de la Fournaise (PdF), in the western Indian Ocean, is a very active hot spot basaltic volcano whose eruptions (1-2 per year on average) are well anticipated by the local seismic-geodetic monitoring network. Here we report on the first cross-correlated measurements of seismic tremor, magmatic gas composition (OP-FTIR absorption spectroscopy and in situ MultiGas analysis plus filter-pack sampling), gas fluxes (DOAS) and magma extrusion rate (space-borne MODIS data) during a 2-weeks long dyke eruption at PDF in October 2010. Precursory seismic signals indicated dyke ascent in a few hours from a reservoir located at ~2.5 km beneath the summit crater. After an initial burst coinciding with eruptive fissure opening, both the tremor amplitude, lava extrusion rate and SO2 flux coherently decreased during the first week of eruption. The co-emitted magmatic gases, whose composition varied slightly over time, were found to have a high water content (95-98 mol %), high SO2/HCl and low CO2/SO2, HCl/HF and Cl/Br ratios, consistent with a hydrous hot spot mantle source. By comparing gas fluxes with the magma co-extrusion rate and available melt inclusion data, we infer an essentially syn-eruptive (closed system) degassing for sulfur, chlorine and fluorine during the first half of the eruption. In contrast, additions of CO2 (previously accumulated or/and bubbling differentially) and H2O (external contribution from the hydrothermal system?) are required to explain the gas composition. Differential CO2 bubbling is supported by high frequency correlations between the CO2/HCl ratio and seismic tremor. The second part of the eruption was marked by a spectacular decoupling between re-increasing seismic tremor and declining lava extrusion, indicating a key control of tremor and eruptive activity by differential (open system) gas bubbling across the feeder dyke. This was associated with an increasing contribution of the low-frequency (1-3 Hz) spectral band to the tremor amplitude. Finally, the end of the eruption was preceded by a new sharp tremor increase, with remarkable anti-correlated variations of the 1-3 Hz and 3-5 Hz spectral signals, which we tentatively attribute to an abrupt geometrical change prior to dyke closure. These results, and future ones, are expected to contribute to better understanding and forecasting of eruption processes at Piton de la Fournaise volcano.

Allard, P.; La Spina, A.; Tamburelllo, G.; Aiuppa, A.; Coquet, A.; Brenguier, F.; Coppola, D.; Di Muro, A.; Burton, M. R.; Staudacher, T.

2011-12-01

267

The off-shore continuation of an active basaltic volcano: Piton de la Fournaise (Réunion Island, Indian Ocean); structural and geomorphological interpretation from sea beam mapping  

NASA Astrophysics Data System (ADS)

In 1984 a Sea Beam survey of the submarine east flank of Piton de la Fournaise was performed with R/V "Jean Charcot". Three main types of volcanic or volcano-tectonic features have been identified: (1) The subaerial NE and SE volcanic rift zones of Piton de la Fournaise do not extend more than about five kilometers offshore. Unlike typical Hawaiian rift zones, which form narrow (2-4 km) ridges extending tens of kilometers from the summit, the active rift zones of Piton de la Fournaise widen downslope, attaining more than 10 km at their front. (2) The submarine extension of the Grand Brûlé slide is larger than the subaerial portion. The entire slide forms a 7 × 24 km scar bounded by two ramparts to the north and south. The slumped material may have moved as a debris flow, forming a large talus downslope of the slide. However, the submarine counterpart of the south area of the Grand Brûlé seems to be composed by a slumped block whose structure is apparently not disturbed. (3) Another prominent feature is a conspicuous topographic high that occupies nearly all the center of the surveyed zone. This "cast flank submarine plateau" cannot be associated with any active structure of Piton de la Fournaise. Its surface generally dips gently (2-3°), and its northern and southern flanks are extensively cut by landslides. Cones of variable dimensions are observed on the plateau and farther to the east. Three hypotheses are examined to account for the origin of this morphology: (a) remnant flank of an ancestral Fournaise volcano associated with a large buried intrusion found by drilling beneath the Grand Brûlé; (b) distinct volcanic massif or (c) material of a huge and ancient landslide. The geophysical data show that the western part of this submarine plateau is reversely magnetized and associated with a moderate positive gravity anomaly. This confirms that, as suggested by the bathymetric analysis, this part of the plateau is relatively coherent. Conversely, the eastern portion of the plateau appears to be poorly magnetized and composed of low-density material, probably chaotic materials derived from landslides. The reversed magnetization of the western part shows that the whole structure is older than 0.7 Ma. These results show that the volcanic history of Piton de la Fournaise is more complex than previously thought.

Lénat, Jean-François; Vincent, Pierre; Bachélery, Patrick

1989-01-01

268

Serpentinites and low-K island arc meta-volcanic rocks in the Lower Köli Nappe of the central Scandinavian Caledonides: Late Cambrian-early Ordovician serpentinite mud volcanoes in a forearc basin?  

NASA Astrophysics Data System (ADS)

The late Cambrian to early Ordovician meta-volcanic rocks of the Caledonian Lower Köli Nappe consist mainly of tholeiitic low-K island arc basalts, andesites, and rhyodacites. The dominance of rhyodacites in this meta-volcanic succession raises the question on whether fractional crystallization or partial melting were involved in their origin. Low Mg#, low Cr and Ni contents and compositional trends imply at least two stages of fractional crystallization for the origin of the meta-volcanic rocks. Sedimentary-hosted serpentinites occur stratigraphically below and above the meta-volcanic rocks raising the question on their origin. Geochemical data indicate strongly depleted harzburgitic-dunitic peridotite as precursor rocks of the serpentinites. Unusually high contents of As, Sb, Pb in these serpentinites are not in agreement with a depleted mantle geochemistry, but indicate enrichment by fluids from the subducted slab during serpentinization in the mantle wedge. The massive, detrital, and in places fossiliferous serpentinite bodies within the sedimentary host-rocks point to former serpentinite mud volcanoes within a non-accretionary forearc. Therefore it is suggested that the highly fractionated volcanic rocks were emplaced as lava flows and shallow intrusions in sedimentary forearc successions implying that the Lower Köli Nappe was part of a much larger trench-arc complex involving at least the immediate hanging wall Middle Köli Stikke Nappe.

Grimmer, Jens C.; Greiling, Reinhard O.

2012-05-01

269

Isotopic and trace element geochemistry of lavas from the northern Mariana and southern volcano arcs  

Microsoft Academic Search

Samples from submarine volcanoes and islands were analyzed for concentrations of K, Rb, Sr, Ba, REE, ⁸⁷Sr\\/⁸⁶Sr and some selected samples for ¹⁴³Nd\\/¹⁴⁴Nd. These data show strong variations along the arc, being relatively depleted in the tholeiitic and low-K calc-alkaline volcanoes of the Volcano Arc (VA) and the Mariana Central Island Province (CIP). All of the Mariana Northern Seamount Province

Lin Pingnan

1989-01-01

270

Volcano Lovers  

NSDL National Science Digital Library

This Why Files article explores volcanoes and volcanic eruptions. Topics covered include: Alaska's Pavlof and its threat to jet engines; Mexico City's restless neighbor, Popocatepetl (El Popo); underground volcanic processes; modern forecasting of eruptions; various volcanic phenomena and features; large flood basalt areas around the world; California's volcanically active area, Long Valley Caldera and Mammoth Mountain; Indonesia's Krakatau eruption in 1883, which was the world's largest historical eruption; Krakatau's ecological contribution to the study of colonization of sterile lands; and central Mexico's Paricutin which was witnessed emerging from a farmer's field in 1943. Three scientists were interviewed for this article.

Tenenbaum, David

1997-01-02

271

Kilauea volcano eruption seen from orbit  

NASA Technical Reports Server (NTRS)

The STS-51 crew had a clear view of the erupting Kilauea volcano during the early morning pass over the Hawaiian islands. Kilauea, on the southwest side of the island of Hawaii, has been erupting almost continuously since January, 1983. Kilauea's summit caldera, with the smaller Halemaumau crater nestled within, is highlighted in the early morning sun (just above the center of the picture). The lava flows which covered roads and subdivisions in 1983-90 can be seen as dark flows to the east (toward the upper right) of the steam plumes on this photo. The summit crater and lava flows of Mauna Loa volcano make up the left side of the photo. Features like the Volcano House and Kilauea Visitor Center on the edge of the caldera, the small subdivisions east of the summit, Ola's Rain Forest north of the summit, and agricultural land along the coast are easily identified.

1993-01-01

272

Hawaiian Volcano Observatory  

NSDL National Science Digital Library

As part of the US Geological Survey, the Hawaiian Volcano Observatory (HVO) is charged with monitoring and researching volcanoes in Hawaii. The site provides current activity reports, hazard information, and a history of the two main volcanoes, Kilauea and Mauna Loa. In addition, the site provides information on three other volcanoes that are either active or potentially active. Visitors can also learn about earthquakes in Hawaii and the particular hazards posed by volcanos. Captivating photos help bring the volcanoes to life. Visitors can patronize the Photo Gallery for additional volcano photos. Cross links to additional information and sites are provided on every page.

273

Comparison of the submarine landslide by the sector collapse of Oshima-Oshima island in the northern part of Japan with the debris avalanche of off Kaimon volcano in the southern part of Japan and several landslide.  

NASA Astrophysics Data System (ADS)

Oshima-Oshima island is an active volcano located in the eastern margin of the Japan Sea off Hokkaido. Oshima-Oshima consists of Higashi-yama somma, Nishi-yama somma, and the central cone. The latest eruption occurred at the 18th century. In a huge eruption on August 1741 , Nishiyama of western part of Oshima- Oshima collapsed toward the northern submarine slope , and the horseshoe shape caldera was formed. It is proposed by Katsui et al.(1977) , Satake and Kato(2001) that Japan Sea tsunami in 1741 was generated by this collapse. Detailed swath bathymetry surveys have been conducted around Oshima-Oshima by Hydrographic and Oceanographic Department of Japan in 1993. As a result, a large area of debris avalanche deposits has been discovered on the northern submarine flanks of Oshima-Oshima island. In addition, sidescan sonar surveys was also conducted by Hydrographic and Oceanographic Department of Japan and University of Tokyo in 1995. In 1997, the lower part of the debris avalanche deposit was investigated using submersible 'Shinkai 2000' by JAMSTEC(Japan Agency for Marine-Earth Science and Technology). It was confirmed that those deposits were Oshima origins (Kato,1997). We compiled and analyzed using these detailed bathymetry data and sidescan data. As a result , we clarified a detailed geographical features of debris avalanche and the limit of their distribution. Scarp of caldera rim continues to approximately 1100m under the sea. Oshima-Oshima has diameter of approximately 16km. Oshima-Oshima has also an estimated total edifice volume (subaerial and submarine) of 127km3 and rises about 2200m from its base in 1500m depth of water. Northern part of Oshima-Oshima, the scarp of caldera rim on the subaerial area consecutively continues up to about 1100m of depth. The scarp has 100m-300m high, and width of landslide valley is about 2km. Hammocky surface starts from 1100m depth of water. Sea mount of like spur is composed of the collapse deposits has almost extended to the whole area in the trough deeper than 1100m. Debris avalanche deposits have been identified up to 2200m depth and 24km from Oshima-Oshima island, H/L is approximately 0.12. Maximum sizes of debris avalanche block is up to 1-2km width and 100m high. We divided the debris avalanche deposits into three areas (Type A-C) by the topography. Type-A is the main sedimentary area in front of the collapse area and the form is like a spur with 100 to 130m height. Type-B has a form like a knoll or block. Type-C shows gradual slope containing a small rise. We compared these feature with debris avalanche of off Kaimon volcano in the southern part of Japan and the other debris avalanche (landslide, submarine landslide).

Kaji, T.; Yamazaki, H.; Kato, Y.

2007-12-01

274

Monitoring ground deformations at active Neapolitan volcanoes  

Microsoft Academic Search

The Neapolitan volcanic area, located in the south sector of the Campanian plain, includes three active volcanoes: Somma-Vesuvio, Campi Flegrei Caldera, and Ischia Islands. Somma-Vesuvio (last eruption occurred in 1944) is characterized by a low level seismic and ground deformation activity; Campi Flegrei Caldera (last eruption occurred in 1538) is characterized by slow deformation and several bradyiseismic events. During the

F. Pingue; C. del Gaudio; G. de Natale; F. Obrizzo; V. Sepe; G. Cecere; P. de Martino; V. Siniscalchi; U. Tammaro

2003-01-01

275

The Electronic Volcano  

NSDL National Science Digital Library

The Electronic Volcano offers links to many types of information on active volcanoes, such as maps, photographs, full texts of dissertations and a few elusive documents. The Electronic Volcano will guide you to resources in libraries or resources on other information servers including catalogs of active volcanoes, datasets for literature citations, electronic and hard-copy journals, visual information, maps, observatories and institutions, and a volcano name and country index.

276

Earth Layers and Volcanoes  

NSDL National Science Digital Library

Why do we have volcanoes? Use the information on the websites to answer the questions on the worksheet. Worksheet First, review the layers of the earth. Labeling the layers game Next, go through the maze and read the information given. Magic School Bus volcano game Now, study the different shapes of volcanoes. Click enter, then volcano types in the menu. Read about the 3 types of volcanoes. Discovery Kids Games Finally, watch ...

Brookeshallow

2011-04-13

277

Tutorial on Reed-Solomon error correction coding  

NASA Technical Reports Server (NTRS)

This tutorial attempts to provide a frank, step-by-step approach to Reed-Solomon (RS) error correction coding. RS encoding and RS decoding both with and without erasing code symbols are emphasized. There is no need to present rigorous proofs and extreme mathematical detail. Rather, the simple concepts of groups and fields, specifically Galois fields, are presented with a minimum of complexity. Before RS codes are presented, other block codes are presented as a technical introduction into coding. A primitive (15, 9) RS coding example is then completely developed from start to finish, demonstrating the encoding and decoding calculations and a derivation of the famous error-locator polynomial. The objective is to present practical information about Reed-Solomon coding in a manner such that it can be easily understood.

Geisel, William A.

1990-01-01

278

Volcanic Island Appears Near Tonga  

NASA Astrophysics Data System (ADS)

A volcano known as Home Reef is now believed to be the source of a small island that appeared recently in Tonga, accordingto scientists from the Smithsonian Institution's Global Volcanism Program who had initially placed the location of the eruption and resulting island at nearby Metis Shoal. Mariners onboard the yacht Maiken

Zielinski, Sarah

2006-11-01

279

VLSI architecture for a Reed-Solomon decoder  

NASA Technical Reports Server (NTRS)

A basic single-chip building block for a Reed-Solomon (RS) decoder system is partitioned into a plurality of sections, the first of which consists of a plurality of syndrome subcells each of which contains identical standard-basis finite-field multipliers that are programmable between 10 and 8 bit operation. A desired number of basic building blocks may be assembled to provide a RS decoder of any syndrome subcell size that is programmable between 10 and 8 bit operation.

Hsu, In-Shek (inventor); Truong, Trieu-Kie (inventor)

1992-01-01

280

Roving the Pacific: Pacific Manuscripts Bureau Microfilming in the Pacific Islands.  

ERIC Educational Resources Information Center

Provides an overview of microfilming by the Pacific Manuscripts Bureau (PMB), a non-profit organization established in 1968 to identify and preserve archives, manuscripts, and rare printed documents relating to the South Pacific Islands. Describes a 1997 PMB microfilming expedition to Papua New Guinea and the Solomon Islands. (PEN)

Maidment, Ewan

1998-01-01

281

Super Volcano  

NSDL National Science Digital Library

Deep beneath the surface of Earth lies one of the most destructive and yet least understood of the natural forces on the planet: the super volcano. This radio broadcast presents discussions with scientists at Yellowstone National Park who are investigating this potentially devastating natural phenomenon. Yellowstone National Park is one of the largest supervolcanoes in the world. It last erupted 640,000 years ago and scientists are now predicting that the next eruption may not be far off. To discover more, a new volcanic observatory has been built in the park to monitor the extreme volcanic activity going on beneath the surface of this much visited destination. The broadcast is 30 minutes in length.

282

Instrumentation Recommendations for Volcano Monitoring at U.S. Volcanoes Under the National Volcano Early Warning System  

USGS Publications Warehouse

As magma moves toward the surface, it interacts with anything in its path: hydrothermal systems, cooling magma bodies from previous eruptions, and (or) the surrounding 'country rock'. Magma also undergoes significant changes in its physical properties as pressure and temperature conditions change along its path. These interactions and changes lead to a range of geophysical and geochemical phenomena. The goal of volcano monitoring is to detect and correctly interpret such phenomena in order to provide early and accurate warnings of impending eruptions. Given the well-documented hazards posed by volcanoes to both ground-based populations (for example, Blong, 1984; Scott, 1989) and aviation (for example, Neal and others, 1997; Miller and Casadevall, 2000), volcano monitoring is critical for public safety and hazard mitigation. Only with adequate monitoring systems in place can volcano observatories provide accurate and timely forecasts and alerts of possible eruptive activity. At most U.S. volcanoes, observatories traditionally have employed a two-component approach to volcano monitoring: (1) install instrumentation sufficient to detect unrest at volcanic systems likely to erupt in the not-too-distant future; and (2) once unrest is detected, install any instrumentation needed for eruption prediction and monitoring. This reactive approach is problematic, however, for two reasons. 1. At many volcanoes, rapid installation of new ground-1. based instruments is difficult or impossible. Factors that complicate rapid response include (a) eruptions that are preceded by short (hours to days) precursory sequences of geophysical and (or) geochemical activity, as occurred at Mount Redoubt (Alaska) in 1989 (24 hours), Anatahan (Mariana Islands) in 2003 (6 hours), and Mount St. Helens (Washington) in 1980 and 2004 (7 and 8 days, respectively); (b) inclement weather conditions, which may prohibit installation of new equipment for days, weeks, or even months, particularly at midlatitude or high-latitude volcanoes; (c) safety factors during unrest, which can limit where new instrumentation can safely be installed (particularly at near-vent sites that can be critical for precursor detection and eruption forecasting); and (d) the remoteness of many U.S. volcanoes (particularly those in the Aleutians and the Marianas Islands), where access is difficult or impossible most of the year. Given these difficulties, it is reasonable to anticipate that ground-based monitoring of eruptions at U.S. volcanoes will likely be performed primarily with instruments installed before unrest begins. 2. Given a growing awareness of previously undetected 2. phenomena that may occur before an eruption begins, at present the types and (or) density of instruments in use at most U.S. volcanoes is insufficient to provide reliable early warning of volcanic eruptions. As shown by the gap analysis of Ewert and others (2005), a number of U.S. volcanoes lack even rudimentary monitoring. At those volcanic systems with monitoring instrumentation in place, only a few types of phenomena can be tracked in near-real time, principally changes in seismicity, deformation, and large-scale changes in thermal flux (through satellite-based remote sensing). Furthermore, researchers employing technologically advanced instrumentation at volcanoes around the world starting in the 1990s have shown that subtle and previously undetectable phenomena can precede or accompany eruptions. Detection of such phenomena would greatly improve the ability of U.S. volcano observatories to provide accurate early warnings of impending eruptions, and is a critical capability particularly at the very high-threat volcanoes identified by Ewert and others (2005). For these two reasons, change from a reactive to a proactive volcano-monitoring strategy is clearly needed at U.S. volcanoes. Monitoring capabilities need to be expanded at virtually every volcanic center, regardless of its current state of

Moran, Seth C.; Freymueller, Jeff T.; LaHusen, Richard G.; McGee, Kenneth A.; Poland, Michael P.; Power, John A.; Schmidt, David A.; Schneider, David J.; Stephens, George; Werner, Cynthia A.; White, Randall A.

2008-01-01

283

Types of Volcanoes  

NSDL National Science Digital Library

This volcano resource introduces the six-type classification system and points out weaknesses of the classic three-type system. The six types of volcanoes are shield volcanoes, strato volcanoes, rhyolite caldera complexes, monogenetic fields, flood basalts, and mid-ocean ridges. For each type of volcano there is a description of both structure and dynamics along with examples of each. You can account for more than ninty percent of all volcanoes with these six types. Additionally, any system will be more useful if you use modifiers from the other potential classification schemes with the morphological types.

284

The origin of the Hawaiian Volcano Observatory  

SciTech Connect

I first stepped through the doorway of the Hawaiian Volcano Observatory in 1976, and I was impressed by what I saw: A dozen people working out of a stone-and-metal building perched at the edge of a high cliff with a spectacular view of a vast volcanic plain. Their primary purpose was to monitor the island's two active volcanoes, Kilauea and Mauna Loa. I joined them, working for six weeks as a volunteer and then, years later, as a staff scientist. That gave me several chances to ask how the observatory had started.

Dvorak, John [University of Hawaii's Institute for Astronomy (United States)

2011-05-15

285

Iceland: Eyjafjallajökull Volcano  

article title:  Ash from Eyjafjallajökull Volcano, Iceland Stretches over the North Atlantic   ... that occurred in late March 2010, the Eyjafjallajökull Volcano in Iceland began erupting again on April 14, 2010. The resulting ash ...

2013-04-17

286

Volcanoes: Annenberg Media Project  

NSDL National Science Digital Library

Volcanoes is an exhibit from the Annenberg Media Project that provides a wealth of information about volcanoes and includes sections such as Melting Rocks, the Dynamic Earth, and Forecasting. Interactive exercises enable the user to learn how rock turns into magma, how to locate volcanoes, and how to decide if building a project near a volcano is safe. Quicktime videos are used for each of the six categories to illustrate the points outlined in the text.

1997-01-01

287

Where are the Volcanoes?  

NSDL National Science Digital Library

This formative assessment item discusses common misconceptions about volcano location around the world. Resources include background and content information as well as alignment to the National Science Education Standards. The probe could easily be modified to be used with a study of earthquakes instead of volcanoes. Teachers can access other resources including facts about volcanoes and lesson ideas.

Fries-Gaither, Jessica

288

How Volcanoes Work  

NSDL National Science Digital Library

This educational resource describes the science behind volcanoes and volcanic processes. Topics include volcanic environments, volcano landforms, eruption dynamics, eruption products, eruption types, historical eruptions, and planetary volcanism. There are two animations, over 250 images, eight interactive tests, and a volcano crossword puzzle.

2011-04-18

289

Monitoring Active Volcanoes  

NSDL National Science Digital Library

This United States Geological Survey (USGS) publication discusses the historic and current monitoring of active volcanoes around the globe. Techniques to measure deviations in pressure and stress induced by subterranean magma movement, as well as other technologies, explain the ways in which researchers monitor and predict volcanoes. Case studies of volcanoes such as Mt. St. Helens, El Chichon, Mauna Loa, and others are discussed.

Tilling, Robert

290

A Scientific Excursion: Volcanoes.  

ERIC Educational Resources Information Center

Reviews an educationally valuable and reasonably well-designed simulation of volcanic activity in an imaginary land. VOLCANOES creates an excellent context for learning information about volcanoes and for developing skills and practicing methods needed to study behavior of volcanoes. (Author/JN)

Olds, Henry, Jr.

1983-01-01

291

Volcano Collapse in the Bismarck Volcanic Arc, Papua New Guinea  

NASA Astrophysics Data System (ADS)

During November and December, 2004, we imaged much of the Bismarck volcanic arc with EM120 swath bathymetry and Hawaii MR1 side-scan aboard the R/V Kilo Moana. Local regions were imaged with the SIO Edgetech chirp system and the WHOI TowCam. In addition, we collected 13 cores and one dredge haul. During this study we identified approximately 12 debris avalanche deposits, including great detail of the 1888 Ritter collapse, discussed separately. Highlights of the other collapse fields includes a large deposit associated with the breach of the caldera on Garove island, debris fields north of Dakataua volcano, both north and south of Karkar volcano, south of Manam volcano, north and south of Crown island, north of Long Island, north of both Tolokiwa and Sakar islands, and south of Bam volcano. Some or many of these debris fields could represent multiple collapses, and many probably generated tsunamis. We expect that all island chains have suffered significant collapses of many of their volcanoes during their histories.

Silver, E.; Day, S.; Ward, S.; Hoffmann, G.; Driscoll, N.; Applegate, B.; Llanes-Estrada, P.; Lyons, A.

2005-12-01

292

How Volcanoes Work: Historical Eruptions  

NSDL National Science Digital Library

This information about major volcanic eruptions in history covers events from the civilization-destroying explosion at Santorini in about 1630 BC, to the killing cloud of carbon dioxide at Lake Nyos Cameroon in 1986. The site documents the seven deadliest eruptions in history. Other eruptions include Mount Pelee on the island of Martinique in 1902, Mount Saint Helens in Washington State in 1980, Nevado Del Ruiz Columbia in 1985, the Mexican eruption of Paricutin in 1943, and the 1883 explosion that nearly obliterated the island of Krakatau in what is now Indonesia. For each eruption the site offers information about the type of volcano, the type of eruption, the products of the eruption, and the relation to plate tectonics. In addition, historical background is provided when appropriate.

Camp, Victor

293

Examples of Mechanism Design: from King Solomon to eBay  

E-print Network

Book of Kings, chapter 3. At some point two women come to king Solomon with a child, because they are ghting over which one of them is the real mother of this child. One of them claims the other has swapped the children overnight because hers has died. Solomon listens to their story and then orders a soldier to cut

de Weerdt, Mathijs

294

Volcano Vents  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

Released 5 May 2003

This low-relief shield volcano imaged with the THEMIS visible camera has two large vents which have erupted several individual lava flows. The positions of the origins of many of the flows indicate that it is probable that the vents are secondary structures that formed only after the shield was built up by eruptions from a central caldera.

Image information: VIS instrument. Latitude 17.6, Longitude 243.6 East (116.4 West). 19 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

2003-01-01

295

The Reed-Solomon encoders: Conventional versus Berlekamp's architecture  

NASA Technical Reports Server (NTRS)

Concatenated coding was adopted for interplanetary space missions. Concatenated coding was employed with a convolutional inner code and a Reed-Solomon (RS) outer code for spacecraft telemetry. Conventional RS encoders are compared with those that incorporate two architectural features which approximately halve the number of multiplications of a set of fixed arguments by any RS codeword symbol. The fixed arguments and the RS symbols are taken from a nonbinary finite field. Each set of multiplications is bit-serially performed and completed during one (bit-serial) symbol shift. All firmware employed by conventional RS encoders is eliminated.

Perlman, M.; Lee, J. J.

1982-01-01

296

Binary weight distributions of some Reed-Solomon codes  

NASA Technical Reports Server (NTRS)

The binary weight distributions of the (7,5) and (15,9) Reed-Solomon (RS) codes and their duals are computed using the MacWilliams identities. Several mappings of symbols to bits are considered and those offering the largest binary minimum distance are found. These results are then used to compute bounds on the soft-decoding performance of these codes in the presence of additive Gaussian noise. These bounds are useful for finding large binary block codes with good performance and for verifying the performance obtained by specific soft-coding algorithms presently under development.

Pollara, F.; Arnold, S.

1992-01-01

297

Island of Hawaii, Hawaiian Archipelago  

NASA Technical Reports Server (NTRS)

This single photo covers almost all of the big island of Hawaii (19.5N, 155.5E) in the Hawaiian Archipelago. The active Kilauea Volcano and lava flow is under clouds and hardly visible at the lower right edge but the Mauna Loa volcano crater and its older lava flow is at the bottom center. The Kona Coast, that produces the only coffee grown in the United States, is to the left. Mauna Kea is the extinct volcano and lava flow in the right center.

1983-01-01

298

Island of Hawaii  

NASA Technical Reports Server (NTRS)

The three main volcanoes which make up the island of Hawaii (19.5N, 155.5W) include the older large shield volcanoes Mauna Loa, Mauna Kea and the more recent Kilauea. The rift zones of Mauna Loa and Mauna Kea are delineated by the black lava flows whereas the smaler Kilauea can be seen venting steam. This color image is one of a pair (see STS052-95-037) to compare the differences between color film and color infrared film.

1992-01-01

299

Glaciation of Haleakala volcano, Hawaii  

SciTech Connect

Early debates regarding the large (5 [times] 10 km) summit crater'' of Haleakala volcano (3,055 m altitude) on the island of Maui attributed its origin to renting, rifting, caldera collapse, or erosion. It now is commonly assumed to have resulted from headward expansion of giant canyons by stream erosion (Stearns, 1942). Slope maps and shaded relief images based on new USGS digital elevation data point to the apparent overfit of the canyons that drain the summit depression. Studies of drowned coral reefs and terraces on the offshore east rift of Haleakala indicate that this part of the volcano has undergone submergence of about 2 km, as well as tilting, since 850 ka ago. Such subsidence indicates that the summit altitude at the end of the shield-building phase reached ca. 5,000 m, well above both the present and full-glacial snowlines. A comparison with the radiometrically dated glacial record of Mauna Kea and its reconstructed snowline history suggests that Haleakala experienced 10 or more glaciations, the most extensive during marine isotope stages 20, 18, and 16. By isotope stage 10, the summit had subsided below the full-glacial snowline. Diamictons on the south slope of the volcano, previously described as mudflows, contain lava clasts with superchilled margins, identical to margins of subglacially erupted lavas on Mauna Kea. Glacier ice that mantled the upper slopes of the volcano continuously for several hundred thousand years and intermittently thereafter, is inferred to have carved Haleakala crater and the upper reaches of large canyons radiating from it.

Moore, J.G.; Mark, R. (Geological Survey, Menlo Park, CA (United States)); Porter, S.C. (Univ. of Washington, Seattle, WA (United States). Quaternary Research Center)

1993-04-01

300

Mt. Erebus: A Surprising Volcano: Grades K-1: Electronic Book  

NSDL National Science Digital Library

This informational text introduces students to Mt. Erebus, a volcano located on Ross Island, just off the coast of Antarctica. Mt. Erebus is the world's southernmost active volcano. The text is written at a kindergarten through grade one reading level. This is an onscreen version that contains recorded narration allowing students to listen to the text as they read along. Highlighted vocabulary words have individually recorded definitions heard by clicking on the links.

Fries-Gaither, Jessica

301

Calculated volumes of individual shield volcanoes at the young end of the Hawaiian Ridge  

Microsoft Academic Search

High-resolution multibeam bathymetry and a digital elevation model of the Hawaiian Islands are used to calculate the volumes of individual shield volcanoes and island complexes (Niihau, Kauai, Oahu, the Maui Nui complex, and Hawaii), taking into account subsidence of the Pacific plate under the load of the Hawaiian Ridge. Our calculated volume for the Island of Hawaii and its submarine

Joel E. Robinson; Barry W. Eakins

2006-01-01

302

Volcanoes: Nature's Caldrons Challenge Geochemists.  

ERIC Educational Resources Information Center

Reviews various topics and research studies on the geology of volcanoes. Areas examined include volcanoes and weather, plate margins, origins of magma, magma evolution, United States Geological Survey (USGS) volcano hazards program, USGS volcano observatories, volcanic gases, potassium-argon dating activities, and volcano monitoring strategies.…

Zurer, Pamela S.

1984-01-01

303

Remarkable geochemical changes and degassing at Voui crater lake, Ambae volcano, Vanuatu  

Microsoft Academic Search

Ambae (also known as Aoba), is a 38×16km2 lozenge-shaped island volcano with a coastal population of around 10000. At the summit of the volcano is lake Voui — one of the largest active crater lakes worldwide, with 40×106m3 of acidic water perched 1400ma.s.l. After more than 300years of dormancy, Ambae volcano reawakened with phreatic eruptions through Voui in 1995, and

Philipson Bani; Clive Oppenheimer; Johan C. Varekamp; Thomas Quinou; Michel Lardy; Simon Carn

2009-01-01

304

Mt. Erebus: A Surprising Volcano: Grades 2-3: text only version  

NSDL National Science Digital Library

This informational text introduces students to Mt. Erebus, a volcano located on Ross Island, just off the coast of Antarctica. Mt. Erebus is the world's southernmost active volcano. The text is written at a grade two through grade three reading level. This is a PDF containing the informational text and a glossary.

Fries-Gaither, Jessica

305

Thermal precursors in satellite images of the 1999 eruption of Shishaldin Volcano  

Microsoft Academic Search

Shishaldin Volcano, Unimak Island Alaska, began showing signs of thermal unrest in satellite images on 9 February 1999. A thermal anomaly and small steam plume were detected at the summit of the volcano in short-wave thermal infrared AVHRR (advanced very high resolution radiometer) satellite data. This was followed by over 2 months of changes in the observed thermal character of

Jonathan Dehn; Kenneson G. Dean; Kevin Engle; Pavel Izbekov

2002-01-01

306

Widespread Uplift and Trapdoor Faulting of Galapagos Volcanoes Observed with Satellite Radar Interferometry  

Microsoft Academic Search

Satellite radar interferometer observations reveal widespread and continuous surface deformation on the western Galapagos Islands of Isabela and Fernandina during the period 1992-2001. All seven major volcanoes, save one, showed sigificant signs of activity although only two eruptions occurred during the observation period. These basaltic shield volcanoes are characterized by large summit calderas and a lack of rift zones. The

H. Zebker; S. Jonsson; F. Amelung; P. Segall

2001-01-01

307

Volcanoes, Observations and Impact  

NASA Astrophysics Data System (ADS)

Volcanoes are critical geologic hazards that challenge our ability to make long-term forecasts of their eruptive behaviors. They also have direct and indirect impacts on human lives and society. As is the case with many geologic phenomena, the time scales over which volcanoes evolve greatly exceed that of a human lifetime. On the other hand, the time scale over which a volcano can move from inactivity to eruption can be rather short: months, weeks, days, and even hours. Thus, scientific study and monitoring of volcanoes is essential to mitigate risk. There are thousands of volcanoes on Earth, and it is impractical to study and implement ground-based monitoring at them all. Fortunately, there are other effective means for volcano monitoring, including increasing capabilities for satellite-based technologies.

Thurber, Clifford; Prejean, Stephanie

308

Space communication system for compressed data with a concatenated Reed-Solomon-Viterbi coding channel  

NASA Technical Reports Server (NTRS)

A space communication system incorporating a concatenated Reed Solomon Viterbi coding channel is discussed for transmitting compressed and uncompressed data from a spacecraft to a data processing center on Earth. Imaging (and other) data are first compressed into source blocks which are then coded by a Reed Solomon coder and interleaver, followed by a convolutional encoder. The received data is first decoded by a Viterbi decoder, followed by a Reed Solomon decoder and deinterleaver. The output of the latter is then decompressed, based on the compression criteria used in compressing the data in the spacecraft. The decompressed data is processed to reconstruct an approximation of the original data-producing condition or images.

Rice, R. F.; Hilbert, E. E. (inventors)

1976-01-01

309

From high quality seismic data acquisition in remote volcanic area to fast data distribution to scientific community: The UnderVolc project on Piton de la Fournaise volcano  

Microsoft Academic Search

Piton de la Fournaise basaltic volcano (La Réunion island, France) is one of the most active volcano in the world with an average of one eruption every year. This volcano is thus an ideal case study for research projects focusing on studying magmatic, seismic and deformation processes occurring in volcanic areas. The UNDERVOLC (UNDERstanding VOLCanic Processes) research project main goal

Florent Brenguier; Philippe Kowalski; Catherine Pequegnat; Frédéric Lauret; Glenn Cougoulat; Patrice Boissier; Philippe Catherine

2010-01-01

310

Strike-slip faulting as a trigger mechanism for overpressure release through piercement structures. Implications for the Lusi mud volcano, Indonesia  

E-print Network

. Implications for the Lusi mud volcano, Indonesia A. Mazzini a,*, A. Nermoen a , M. Krotkiewski a , Y 2009 Accepted 12 March 2009 Available online xxx Keywords: Java, Indonesia Lusi mud volcano Faulting volcano in Indonesia (Mazzini et al., 2007). Lusi became active the 29th of May 2006 on the Java Island

Podladchikov, Yuri

311

Volcanoes generate devastating waves  

Microsoft Academic Search

Although volcanic eruptions can cause many frightening phenomena, it is often the power of the sea that causes many volcano-related deaths. This destruction comes from tsunamis (huge volcano-generated waves). Roughly one-fourth of the deaths occurring during volcanic eruptions have been the result of tsunamis. Moreover, a tsunami can transmit the volcano's energy to areas well outside the reach of the

Lockridge

1988-01-01

312

Solomon M. Hsiang Receives 2013 Science for Solutions Award: Citation  

NASA Astrophysics Data System (ADS)

Solomon Hsiang is representative of a new generation in the geosciences community, whose work spans several disciplines, drawing on methods and concepts from far outside the traditional physical science domain in order to make progress on difficult questions at the intersection of natural science, social science, and public policy. Broadly speaking, by examining how humanity has responded to climate variability and change in the distant and recent past, Sol's research elucidates the question of how humanity may respond to a changing climate in the future. Combining large, independent sets of social science, meteorological, and climatological data and analyzing them with tools more common in microeconomics than natural science, Sol, still at an early stage of his career, has made critical contributions to an incipient revolution in our understanding of the sensitivity and adaptability of humans and their social arrangements to climate variability and change. Such insights will greatly improve the information base from which effective public policy is developed.

Oppenheimer, Michael

2014-01-01

313

Alaska Volcano Observatory Monitoring Station  

USGS Multimedia Gallery

An Alaska Volcano Observatory Monitoring station with Peulik Volcano behind. This is the main repeater for the Peulik monitoring network located on Whale Mountain, Beecharaof National Wildlife Refuge....

2009-12-08

314

ANDREW SOLOMON 123 North Linn Street Suite 2C Iowa City, Iowa 52245  

E-print Network

is an outspoken activist and philanthropist for many causes in LGBT rights, mental health, education and the arts. He is founder of the Solomon Research Fellowships in LGBT Studies at Yale University and serves

Thaxton, Christopher S.

315

A review of "Solomonic Iconography in Early Stuart England." by William Tate  

E-print Network

means toward detecting the politics of yet another anti-Solomonic innuendo. The implied reading of Comus seems unfortunately close to Tolstoy?s Prince Stepan enjoying his newspaper article: With his natural quickness of perception, he understood... means toward detecting the politics of yet another anti-Solomonic innuendo. The implied reading of Comus seems unfortunately close to Tolstoy?s Prince Stepan enjoying his newspaper article: With his natural quickness of perception, he understood...

Jonathan Nauman

2003-01-01

316

Reed-Solomon error-correction as a software patch mechanism.  

SciTech Connect

This report explores how error-correction data generated by a Reed-Solomon code may be used as a mechanism to apply changes to an existing installed codebase. Using the Reed-Solomon code to generate error-correction data for a changed or updated codebase will allow the error-correction data to be applied to an existing codebase to both validate and introduce changes or updates from some upstream source to the existing installed codebase.

Pendley, Kevin D.

2013-11-01

317

Iceland: Eyjafjallajökull Volcano  

... to capture a series of images of the Eyjafjallajökull volcano and its erupting ash plume. Figure 1 is a view from MISR's nadir ... The companion image, Figure 2, is a stereo anaglyph (see  Volcano Plume Heights Anaglyph ) generated from the nadir and 46-degree ...

2013-04-17

318

Iceland: Eyjafjallajökull Volcano  

... height map   Ash from Iceland's Eyjafjallajökull volcano, viewed here in imagery from the Multi-angle Imaging SpectroRadiometer ... natural-color, nadir (vertical) view of the scene, with the volcano itself located outside the upper left corner of the image. The ash ...

2013-04-17

319

Chaiten Volcano Still Active  

NSDL National Science Digital Library

This Boston Globe news article shows 12 stunning pictures of the Chaiten Volcano erupting in Chile, its first activity in over 9,000 years. The most recent eruptive phase of the volcano began on May 2, 2008, and is ongoing. The site also has a blog of open, public commentary.

320

Anatomy of a Volcano  

NSDL National Science Digital Library

This interactive from NOVA Online provides a detailed look at the inner workings of one of the world's most dangerous volcanoes, Nyiragongo in the Democratic Republic of Congo. Users can click on highlighted points on a crossection of the volcano to see photos and read about its features and eruptive products.

321

Anatomy of a Volcano  

NSDL National Science Digital Library

This interactive lesson from NOVA Online provides a detailed look at the inner workings of one of the world's most dangerous volcanoes, Nyiragongo in the Democratic Republic of Congo. Users can click on highlighted points on a crossection of the volcano to see photos and read about its features and eruptive products.

2010-12-14

322

Alaska Volcano Observatory at 20  

NASA Astrophysics Data System (ADS)

The Alaska Volcano Observatory (AVO) was established in 1988 in the wake of the 1986 Augustine eruption through a congressional earmark. Even within the volcanological community, there was skepticism about AVO. Populations directly at risk in Alaska were small compared to Cascadia, and the logistical costs of installing and maintaining monitoring equipment were much higher. Questions were raised concerning the technical feasibility of keeping seismic stations operating through the long, dark, stormy Alaska winters. Some argued that AVO should simply cover Augustine with instruments and wait for the next eruption there, expected in the mid 90s (but delayed until 2006), rather than stretching to instrument as many volcanoes as possible. No sooner was AVO in place than Redoubt erupted and a fully loaded passenger 747 strayed into the eruption cloud between Anchorage and Fairbanks, causing a powerless glide to within a minute of impact before the pilot could restart two engines and limp into Anchorage. This event forcefully made the case that volcano hazard mitigation is not just about people and infrastructure on the ground, and is particularly important in the heavily traveled North Pacific where options for flight diversion are few. In 1996, new funding became available through an FAA earmark to aggressively extend volcano monitoring far into the Aleutian Islands with both ground-based networks and round-the-clock satellite monitoring. Beyond the Aleutians, AVO developed a monitoring partnership with Russians volcanologists at the Institute of Volcanology and Seismology in Petropavlovsk-Kamchatsky. The need to work together internationally on subduction phenomena that span borders led to formation of the Japan-Kamchatka-Alaska Subduction Processes (JKASP) consortium. JKASP meets approximately biennially in Sapporo, Petropavlovsk, and Fairbanks. In turn, these meetings and support from NSF and the Russian Academy of Sciences led to new international education and research opportunities for Russian and American students. AVO was a three-way partnership of the federal and state geological surveys and the state university from the start. This was not a flowering of ecumenism but was rather at the insistence of the Alaska congressional delegation. Such shared enterprises are not managerially convenient, but they do bring a diversity of roles, thinking, and expertise that would not otherwise be possible. Through AVO, the USGS performs its federally mandated role in natural hazard mitigation and draws on expertise available from its network of volcano observatories. The Alaska Division of Geological and Geophysical Surveys performs a similar role at the state level and, in the tradition of state surveys, provides important public communications, state data base, and mapping functions. The University of Alaska Fairbanks brought seismological, remote sensing, geodetic, petrological, and physical volcanological expertise, and uniquely within US academia was able to engage students directly in volcano observatory activities. Although this "model" cannot be adopted in total elsewhere, it has served to point the USGS Volcano Hazards Program in a direction of greater openness and inclusiveness.

Eichelberger, J. C.

2008-12-01

323

Alaska Volcano Observatory  

NSDL National Science Digital Library

This is the homepage of the Alaska Volcano Observatory, a joint program of the United States Geological Survey (USGS), the Geophysical Institute of the University of Alaska Fairbanks (UAFGI), and the State of Alaska Division of Geological and Geophysical Surveys (ADGGS). Users can access current information on volcanic activity in Alaska and the Kamchatka Penninsula, including weekly and daily reports and information releases about significant changes in any particluar volcano. An interactive map also directs users to summaries and activity notifications for selected volcanoes, or through links to webcams and webicorders (recordings of seismic activity). General information on Alaskan volcanoes includes descriptions, images, maps, bibliographies, and eruptive histories. This can be accessed through an interactive map or by clicking on an alphabetic listing of links to individual volcanoes. There is also an online library of references pertinent to Quaternary volcanism in Alaska and an image library.

324

Transport of Fine Ash Through the Water Column at Erupting Volcanoes - Monowai Cone, Kermadec-Tonga Arc  

NASA Astrophysics Data System (ADS)

Monowai cone is a large, active, basaltic stratovolcano, part of the submarine Monowai volcanic center (MVC) located at ~26°S on the Kermadec-Tonga arc. At other actively erupting submarine volcanoes, magma extrusions and hydrothermal vents have been located only near the summit of the edifice, generating plumes enriched with hydrothermal components and magmatic gasses that disperse into the ocean environment at, or shallower than, the summit depth. Plumes found deeper than summit depths are dominated by fresh volcaniclastic ash particles, devoid of hydrothermal tracers, emplaced episodically by down-slope gravity flows, and transport fine ash to 10’s of km from the active eruptions. A water column survey of the MVC in 2004 mapped intensely hydrothermal-magmatic plumes over the shallow (~130 m) summit of Monowai cone and widespread plumes around its flanks. Due to the more complex multiple parasitic cone and caldera structure of MVC, we analyzed the dissolved and particulate components of the flank plumes for evidence of additional sources. Although hydrothermal plumes exist within the adjacent caldera, none of the parasitic cones on Monowai cone or elsewhere within the MVC were hydrothermally or volcanically active. The combination of an intensely enriched summit plume, sulfur particles and bubbles at the sea surface, and ash-dominated flank plumes indicate Monowai cone was actively erupting at the time of the 2004 survey. Monowai cone is thus the fourth erupting submarine volcano we have encountered, and all have had deep ash plumes distributed around their flanks [the others are: Kavachi (Solomon Island arc), NW Rota-1 (Mariana arc) and W Mata (NE Lau basin)]. These deep ash plumes are a syneruptive phenomenon, but it is unknown how they are related to eruptive style and output, or to the cycles of construction and collapse that occur on the slopes of submarine volcanoes. Repeat multibeam bathymetric surveys have documented two large-scale sector collapse events at Monowai and one at NW Rota-1, as well as constructional deposits extending down the flanks of these volcanoes. Acoustic records at Monowai and NW Rota-1 suggest sector collapse events are infrequent while eruptions, and the resulting supply of depositional material, have been nearly continuous. The sector collapse events occurred at times remote from our plume surveys, so, large landslide events are not a prerequisite for the presence of deep ash plumes. Despite a wide range of summit depths (<10 m at Kavachi to 1500 m at W Mata), lava types (basaltic-andesite, boninite, and basalt), and eruptive styles (Surtseyan, Strombolian, and effusive flows with active pillow formation), the deep particle plumes at each of these volcanoes are remarkably similar in their widespread distribution (to 10’s of km from the summit and at multiple depths down the flanks) and composition (dominantly fresh volcanic ash). Moderate eruption rates, lava-seawater interaction and steep slopes below an eruptive vent may be sufficient to initiate the transport of fine ash into the ocean environment and distal sediments via these types of plumes.

Walker, S. L.; Baker, E. T.; Leybourne, M. I.; de Ronde, C. E.; Greene, R.; Faure, K.; Chadwick, W.; Dziak, R. P.; Lupton, J. E.; Lebon, G.

2010-12-01

325

Bathymetry of southern Mauna Loa Volcano, Hawaii  

USGS Publications Warehouse

Manua Loa, the largest volcano on Earth, lies largely beneath the sea, and until recently only generalized bathymetry of this giant volcano was available. However, within the last two decades, the development of multibeam sonar and the improvement of satellite systems (Global Positioning System) have increased the availability of precise bathymetric mapping. This map combines topography of the subaerial southern part of the volcano with modern multibeam bathymetric data from the south submarine flank. The map includes the summit caldera of Mauna Loa Volcano and the entire length of the 100-km-long southwest rift zone that is marked by a much more pronounced ridge below sea level than above. The 60-km-long segment of the rift zone abruptly changes trend from southwest to south 30 km from the summit. It extends from this bend out to sea at the south cape of the island (Kalae) to 4 to 4.5 km depth where it impinges on the elongate west ridge of Apuupuu Seamount. The west submarine flank of the rift-zone ridge connects with the Kahuku fault on land and both are part of the ampitheater head of a major submarine landslide (Lipman and others, 1990; Moore and Clague, 1992). Two pre-Hawaiian volcanic seamounts in the map area, Apuupuu and Dana Seamounts, are apparently Cretaceous in age and are somewhat younger than the Cretaceous oceanic crust on which they are built.

Chadwick, William W.; Moore, James G.; Garcia, Michael O.; Fox, Christopher G.

1993-01-01

326

Volcanoes. A planetary perspective.  

NASA Astrophysics Data System (ADS)

In this book, the author gives an account of the familiar violent aspects of volcanoes and the various forms that eruptions can take. He explores why volcanoes exist at all, why volcanoes occur where they do, and how examples of major historical eruptions can be interpreted in terms of physical processes. Throughout he attempts to place volcanism in a planetary perspective, exploring the pre-eminent role of submarine volcanism on Earth and the stunning range of volcanic phenomena revealed by spacecraft exploration of the solar system.

Francis, P.

327

AVO: Alaska Volcano Observatory  

NSDL National Science Digital Library

This site illustrates the Alaska Volcano Observatory's (AVO) objective to monitor Alaska's volcanoes for the purpose of forecasting volcanic activity and alleviating hazards. AVO's seismometers and satellite imagery allow visitors to obtain current information on selected volcanoes. Because AVO is responsible for volcanic emergencies, people in Alaska can visit the Web site to determine their vulnerability. The site also features AVO's research in geological mapping, modeling of magnetic systems, and development of new instrumentation for predication and interpretation of volcanic unrest. Everyone can appreciate the images of past volcanic eruptions.

328

Homochiral and meso figure eight knots and a Solomon link.  

PubMed

A homochiral naphthalenediimide-based building block forms in water a disulfide library of macrocycles containing topological isomers. We attempted to identify each of these isomers, and explored the mechanisms leading to their formation. The two most abundant species of the library were assigned as a topologically chiral Solomon link (60% of the library, as measured by high-performance liquid chromatography (HPLC)) and a topologically achiral figure eight knot (18% by HPLC), competing products with formally different geometries but remarkably similar 4-fold symmetries. In contrast, a racemic mixture of building blocks gives the near-quantitative formation of another new and more stable structure, assigned as a meso figure eight knot. Taken together, these results seem to uncover a correlation between the point chirality of the building block used and the topological chirality of the major structure formed. These and the earlier discovery of a trefoil knot also suggest that the number of rigid components in the building block may translate into corresponding knot symmetry and could set the basis of a new strategy for constructing complex topologies. PMID:24831779

Ponnuswamy, Nandhini; Cougnon, Fabien B L; Panto?, G Dan; Sanders, Jeremy K M

2014-06-11

329

Vent of Sand Volcano  

USGS Multimedia Gallery

Vent of sand volcano produced by liquefaction is about 4 ft across in strawberry field near Watsonville. Strip spanning vent is conduit for drip irrigation system. Furrow spacing is about 1.2 m (4 ft) on center....

2009-01-26

330

Camera formation and more, but what comes next? an analysis of volcanic threat of Nisyros island, Greece  

NASA Astrophysics Data System (ADS)

We present an analysis of volcanic threat of Nisyros island (Greece) based on a catalogue of questions compiled for the USGS National Volcano Early Warning System (NVEWS). We find that the score puts Nisyros in the league of volcanoes posing a very high threat. US volcanoes with a comparable threat level include Mt. St. Helens, Augustine and the Long Valley caldera.

Winson, A.; Kinvig, H.; Gottsmann, J.; Partington, E.; Geyer, A.

2008-10-01

331

Volcano Watch Satellite Images  

NSDL National Science Digital Library

The University of Wisconsin's Space Science and Engineering Center displays these satellite images of the world's ten most active volcanoes. Users can view images of the Colima Volcano in Central Mexico or Mount Etna in Sicily, Italy. The latest images are updated every half-hour. Also, a Java animation feature splices together the last four images to show a simulation over a two-hour period.

332

Relationships between volcano gravitational spreading and magma intrusion  

NASA Astrophysics Data System (ADS)

Volcano spreading, with its characteristic sector grabens, is caused by outward flow of weak substrata due to gravitational loading. This process is now known to affect many present-day edifices. A volcano intrusive complex can form an important component of an edifice and may induce deformation while it develops. Such intrusions are clearly observed in ancient eroded volcanoes, like the Scottish Palaeocene centres, or in geophysical studies such as in La Réunion, or inferred from large calderas, such as in Hawaii, the Canaries or Galapagos volcanoes. Volcano gravitational spreading and intrusive complex emplacement may act simultaneously within an edifice. We explore the coupling and interactions between these two processes. We use scaled analogue models, where an intrusive complex made of Golden syrup is emplaced within a granular model volcano based on a substratum of a ductile silicone layer overlain by a brittle granular layer. We model specifically the large intrusive complex growth and do not model small-scale and short-lived events, such as dyke intrusion, that develop above the intrusive complex. The models show that the intrusive complex develops in continual competition between upward bulging and lateral gravity spreading. The brittle substratum strongly controls the deformation style, the intrusion shape and also controls the balance between intrusive complex spreading and ductile layer-related gravitational spreading. In the models, intrusive complex emplacement and spreading produce similar structures to those formed during volcano gravitational spreading alone (i.e. grabens, folds, en échelon fractures). Therefore, simple analysis of fault geometry and fault kinetic indicators is not sufficient to distinguish gravitational from intrusive complex spreading, except when the intrusive complex is eccentric from the volcano centre. However, the displacement fields obtained for (1) a solely gravitational spreading volcano and for (2) a gravitational spreading volcano with a growing and spreading intrusive complex are very different. Consequently, deformation fields (like those obtained from geodetic monitoring) can give a strong indication of the presence of a spreading intrusive complex. We compare the models with field observations and geophysical evidence on active volcanoes such as La Réunion Island (Indian Ocean), Ometepe Island (Nicaragua) and eroded volcanic remnants such as Ardnamurchan (Scotland) and suggest that a combination between gravitational and intrusive complex spreading has been active.

Delcamp, Audray; van Wyk de Vries, Benjamin; James, Mike R.; Gailler, L. S.; Lebas, E.

2012-04-01

333

Perception of Lava Flow Hazards and Risk at Mauna Loa and Hualalai Volcanoes, Kona, Hawaii  

Microsoft Academic Search

The island of Hawaii is composed of five sub-aerially exposed volcanoes, three of which have been active since 1801 (Kilauea, Mauna Loa, Hualalai). Hawaii has the fastest population growth in the state and the local economy in the Kona districts (i.e., western portion of the island) is driven by tourism. Kona is directly vulnerable to future lava flows from Mauna

C. E. Gregg; B. F. Houghton; D. M. Johnston; D. Paton; D. A. Swanson

2001-01-01

334

Oceanic transports through the Solomon Sea: The bend of the New Guinea Coastal Undercurrent  

NASA Astrophysics Data System (ADS)

Thermocline waters of the tropical southwest Pacific can be traced back to the center of the South Pacific basin and have a potential influence on equatorial surface conditions and on the characteristics of the El Niño Southern Oscillation on decadal timescales. The Solomon Sea is traversed by this influential flow, and therefore is an optimal place for exploring this oceanic connection to the equator. From a high-resolution hydrographic survey at which we applied an inverse box model, we describe the main pathways at the entrance of the Solomon Sea, and more particularly the extremely sharp bend of the western boundary current around the south-east tip of Papua New Guinea. Of the 30 Sv subtropical waters transported into the Coral Sea from the east, above 1300 m, 29 ± 5 Sv makes its way through the Solomon Sea with a large part transported in a boundary current, at the entrance of the Solomon Sea. Around the south-east tip of Papua New Guinea, the Gulf of Papua Current turns abruptly to the north, in a very sharp bend as it merges into the New Guinea Coastal Undercurrent, on its way, toward the equator. The warm currents transport large amounts of internal energy, with a total of 1.0 ± 0.3 1015W entering the Solomon Sea from the south.

Gasparin, Florent; Ganachaud, Alexandre; Maes, Christophe; Marin, Frédéric; Eldin, Gérard

2012-08-01

335

Regional setting of a complex backarc: New Hebrides Arc, northern Vanatu-eastern Solomon Islands  

NASA Astrophysics Data System (ADS)

New GLORIA imagery over the complex backarc area of the northern New Hebrides Arc clearly outlines the deeply faulted Jean Charcot Troughs. The troughs are 2400 3000 m deep and are not magmatically active. They appear to be fragmented older crust and are not backarc basins in the usual sense. Horst and graben structures on the Hazel Holme Fracture Zone (HHFZ) cut obliquely across the trend of the Zone, which therefore is not a simple transform. The enechelon ridges may form a relay, but Y-shaped grabens could be remnant spreading zones, formed earlier in the history of the western part of the North Fiji Basin.

Johnson, D. P.; Maillet, P. C.; Price, R.

1993-06-01

336

What is a volcano?  

NASA Astrophysics Data System (ADS)

In a volcano, magma, generated at a source in a planetary interior, flows upward with varying amounts of physicochemical evolution, intruding the encasing rocks. Once near the top of the lithosphere, that is at a major rigid-fluid, high-low-density interface, the magma erupts, piercing this interface. While gas, vapors and thinnest particles mix up with the atmosphere and stratosphere, larger drops and particles will eventually accumulate on top of the interface to form volcanic deposits, giving rise in the area around the crater to a volcanic edifice. In turn, these deposits may be intruded or modified by magma, eruptions, geothermal fluids, tectonics, erosion, landsliding and all other kinds of geologic processes. In this view, volcanism is a self-similar process that ranges many orders of magnitude in space and time scales from small cinder cones to large ocean ridges. For instance, at Amiata Volcano, Italy, many of the above mentioned processes have interacted. The volcano is deeply dissected by volcanic spreading, to the point of loosing its original cone-like shape; large diapirs and thrust-related structure have formed in the clay- and gypsum-rich substratum all around the volcano generating dismembered lava flows. In addition, the spreading have created the conditions for the existence of mercury mineralization and geothermal reservoirs. All this complexity that, in our opinion must be considered volcanic is not easy described by commonly used definitions of volcanoes. In fact, former definitions of "volcano", for instance that from the Glossary of Geology (1997) "a vent in the surface of the Earth through which magma and associated gases and ash erupt" or "the form or structure, usually conical, that is produced by the ejected material" are clearly insufficient and cannot capture the geologic complexity of a real volcanic environment. All definitions, that we encountered, tend to consider volcanoes from the point of view of a single discipline, each of them neglecting relevant aspects belonging to other disciplines. For the two cases mentioned above a volcano is seen only from the point of view of eruptive activity or of morphology. We attempt to look at "volcano" holistically to provide a more comprehensive definition. We define a volcano as a geologic environment that, at any scale, is characterized by three elements: magma, eruption and edifice. It is sufficient that only one of these elements is proven, as long as the others can be inferred to exist, to have existed, or that will exist.

Borgia, A.; Merle, O.; van Wyk de Vries, B.; Aubert, M.

2007-05-01

337

On the absence of InSAR-detected volcano deformation spanning the 1995–1996 and 1999 eruptions of Shishaldin Volcano, Alaska  

Microsoft Academic Search

Shishaldin Volcano, a large, frequently active basaltic-andesite volcano located on Unimak Island in the Aleutian Arc of Alaska, had a minor eruption in 1995–1996 and a VEI 3 sub-Plinian basaltic eruption in 1999. We used 21 synthetic aperture radar images acquired by ERS-1, ERS-2, JERS-1, and RADARSAT-1 satellites to construct 12 coherent interferograms that span most of the 1993–2003 time

S. C. Moran; O. Kwoun; T. Masterlark; Z. Lu

2006-01-01

338

Contrasts between Antarctic and Arctic ozone depletion Susan Solomon, Robert W. Portmann, and David W. J. Thompson  

E-print Network

Contrasts between Antarctic and Arctic ozone depletion Susan Solomon, Robert W. Portmann, and David.pnas.org/misc/reprints.shtml To order reprints, see: Notes: #12;Contrasts between Antarctic and Arctic ozone depletion Susan Solomon of ozone depletion in the Antarctic and Arctic using available long balloon-borne and ground-based records

339

Hydrologic data collection activities in the Solomon Gulch basin near Valdez, Alaska  

USGS Publications Warehouse

In 1981, the Alaska Power Authority completed construction of a dam spillway at the north end of Solomon Lake near Valdez. Regulation and diversion from the dam since 1982 have significantly altered the natural flow characteristics of Solomon Gulch. In September 1986, the Geological Survey began data collection to determine mean daily discharge at four sites below Solomon Lake and thus document the effects of regulation and diversion of water on the flow at various points in the system. Periodic discharge measurements and continuous records of water stage were obtained at two of the sites, and daily discharge values were computed for all four sites. The report contains descriptions of the data collection sites and the discharge records for each site for September 1986 and water year 1987. (USGS)

Bigelow, B. B.

1988-01-01

340

Real-Time Data Received from Mount Erebus Volcano, Antarctica  

NASA Astrophysics Data System (ADS)

Internal and eruptive volcano processes involve complex interactions of multi-phase fluids with the solid Earth and the atmosphere, and produce diverse geochemical, visible, thermal, elastic, and anelastic effects. Multidisciplinary experimental agendas are increasingly being employed to meet the challenge of understanding active volcanoes and their hazards [e.g., Ripepe et al., 2002; Wallace et al., 2003]. Mount Erebus is a large (3794 m) stratovolcano that forms the centerpiece of Ross Island, Antarctica, the site of the principal U.S. (McMurdo) and New Zealand (Scott) Antarctic bases. With an elevation of 3794 m and a volume of ~1670 km3, Erebus offers exceptional opportunities for extended study of volcano processes because of its persistent, low-level, strombolian activity (Volcano Explosivity Index 0-1) and exposed summit magma reservoir (manifested as a long-lived phonolitic lava lake). Key scientific questions include linking conduit processes to near-field deformations [e.g., Aster et al., 2003], explosion physics [e.g., Johnson et al., 2003], magmatic differentiation and residence [e.g., Kyle et al., 1992], and effects on Antarctic atmospheric and ice geochemistry [e.g., Zreda-Gostynska et al., 1997]. The close proximity of Erebus (35 km) to McMurdo, and its characteristic dry, windy, cold, and high-elevation Antarctic environment, make the volcano a convenient test bed for the general development of volcano surveillance and other instrumentation under extreme conditions.

Aster, Richard; McIntosh, William; Kyle, Philip; Esser, Richard; Bartel, Beth Ann; Dunbar, Nelia; Johns, Bjorn; Johnson, Jeffrey B.; Karstens, Richard; Kurnik, Chuck; McGowan, Murray; McNamara, Sara; Meertens, Chuck; Pauley, Bruce; Richmond, Matt; Ruiz, Mario

2004-03-01

341

Investigation of the Dashigil mud volcano (Azerbaijan) using beryllium-10  

NASA Astrophysics Data System (ADS)

We collected and analyzed five sediments from three mud volcano (MV) vents and six suspended and bottom sediment samples from the adjoining river near the Dashgil mud volcano in Azerbaijan for 10Be. These three MV are found among the 190 onshore and >150 offshore MV in this region which correspond to the western flank of the South Caspian depression. These MVs overlie the faulted and petroleum-bearing anticlines. The 10Be concentrations and 10Be/9Be ratios are comparable to the values reported for mud volcanoes in Trinidad Island. It appears that the stable Be concentrations in Azerbaijan rivers are not perturbed by anthropogenic effects and are comparable to the much older sediments (mud volcano samples). The 10Be and 9Be concentrations in our river sediments are compared to the global data set and show that the 10Be values found for Kura River are among the lowest of any river for which data exist. We attribute this low 10Be concentration to the nature of surface minerals which are affected by the residual hydrocarbon compounds that occur commonly in the study area in particular and Azerbaijan at large. The concentrations of 40K and U-Th-series radionuclides (234Th, 210Pb, 226Ra, and 228Ra) indicate overall homogeneity of the mud volcano samples from the three different sites. Based on the 10Be concentrations of the mud volcano samples, the age of the mud sediments could be at least as old as 4 myr.

Kim, K. J.; Baskaran, M.; Jweda, J.; Feyzullayev, A. A.; Aliyev, C.; Matsuzaki, H.; Jull, A. J. T.

2013-01-01

342

Living With Volcanoes: The USGS Volcano Hazards Program  

NSDL National Science Digital Library

This report summarizes the Volcano Hazards Program of the United States Geological Survey (USGS). Topics include its goals and activities, some key accomplishments, and a plan for future operations. There are also discussions of active and potentially active volcanoes in the U.S., the role of the USGS volcano observatories, prediction of eruptions, and potential danger to aircraft from volcanic plumes.

2010-11-11

343

Living With Volcanoes: The USGS Volcano Hazards Program  

NSDL National Science Digital Library

This report summarizes the Volcano Hazards Program of the United States Geological Survey (USGS). Topics include its goals and activities, some key accomplishments, and a plan for future operations. There are also discussions of active and potentially active volcanoes in the U.S., the role of the USGS volcano observatories, prediction of eruptions, and potential danger to aircraft from volcanic plumes.

344

Active monitoring at an active volcano: amplitude-distance dependence of ACROSS at Sakurajima Volcano, Japan  

NASA Astrophysics Data System (ADS)

First testing of volcanic activity monitoring with a system of continuously operatable seismic sources, named ACROSS, was started at Sakurajima Volcano, Japan. Two vibrators were deployed on the northwestern flank of the volcano, with a distance of 3.6 km from the main crater. We successfully completed the testing of continuous operation from 12 June to 18 September 2012, with a single frequency at 10.01 Hz and frequency modulation from 10 to 15 Hz. The signal was detected even at a station that is 28 km from the source, establishing the amplitude decay relation as a function of distance in the region in and around Sakurajima Volcano. We compare the observed amplitude decay with the prediction that was made before the deployment as a feasible study. In the prediction, we used the existing datasets by an explosion experiment in Sakurajima and the distance-dependent amplitude decay model that was established for the ACROSS source in the Tokai region. The predicted amplitude in Sakurajima is systematically smaller than that actually observed, but the dependence on distance is consistent with the observation. On the basis of the comparison of the noise level in Sakurajima Volcano, only 1-day stacking of data is necessary to reduce the noise to the level that is comparable to the signal level at the stations in the island.

Yamaoka, Koshun; Miyamachi, Hiroki; Watanabe, Toshiki; Kunitomo, Takahiro; Michishita, Tsuyoshi; Ikuta, Ryoya; Iguchi, Masato

2014-12-01

345

Volcanoes: Coming Up from Under.  

ERIC Educational Resources Information Center

Provides specific information about the eruption of Mt. St. Helens in March 1980. Also discusses how volcanoes are formed and how they are monitored. Words associated with volcanoes are listed and defined. (CS)

Science and Children, 1980

1980-01-01

346

The fast decoding of Reed-Solomon codes using high-radix fermat theoretic transforms  

NASA Technical Reports Server (NTRS)

Fourier-like transforms over GF(F sub n), where F sub n = 2(2n) + 1 is a Fermat prime, are applied in decoding Reed-Solomon codes. It is shown that such transforms can be computed using high-radix fast Fourier transform (FFT) algorithms requiring considerably fewer multiplications than the more usual radix 2 FFT algorithm. A special 256-symbol, 16-symbol-error-correcting, Reed-Solomon (RS) code for space communication-link applications can be encoded and decoded using this high-radix FFT algorithm over GF(F sub 3).

Liu, K. Y.; Reed, I. S.; Truong, T. K.

1976-01-01

347

Earthquakes and Volcanoes  

NSDL National Science Digital Library

This activity has students compare maps of plate tectonics with population density maps and to analyze what these maps imply about the relationship between population and seismic hazards. Students will read about and discuss the theory of plate tectonics, map the regions of the United States that are most susceptible to earthquakes and those that have volcanoes, and list the states that lie on plate boundaries. In addition, they will look at a population density map to determine if people avoid living in areas at high risk for earthquakes and volcanoes. Students will also research specific volcanoes or earthquake zones and write pretend letters to residents of these areas describing the risks. This site also contains suggestions for assessment and ideas for extending the lesson.

2001-01-01

348

The Worlds Deadliest Volcanoes  

NSDL National Science Digital Library

At this interactive site the student attempts to rate the eruption of a volcano according to the Volcanic Explosive Index (VEI). After seeing the step by step eruption of an actual volcano, the student is introduced to VEI scale, which includes a description of the eruption, volume of ejected material, plume height, eruption type, duration, total known eruptions with that VEI, and an example. Each factor is linked to a section where it is explained in detail. After evaluating all of the factors and rating them, the student selects a VEI number and clicks for feedback. The correct answer is given with an explanation.

349

GlobVolcano pre-operational services for global monitoring active volcanoes  

NASA Astrophysics Data System (ADS)

The GlobVolcano project (2007-2010) is part of the Data User Element programme of the European Space Agency (ESA). The project aims at demonstrating Earth Observation (EO) based integrated services to support the Volcano Observatories and other mandate users (e.g. Civil Protection) in their monitoring activities. The information services are assessed in close cooperation with the user organizations for different types of volcano, from various geographical areas in various climatic zones. In a first phase, a complete information system has been designed, implemented and validated, involving a limited number of test areas and respective user organizations. In the currently on-going second phase, GlobVolcano is delivering pre-operational services over 15 volcanic sites located in three continents and as many user organizations are involved and cooperating with the project team. The set of GlobVolcano offered EO based information products is composed as follows: Deformation Mapping DInSAR (Differential Synthetic Aperture Radar Interferometry) has been used to study a wide range of surface displacements related to different phenomena (e.g. seismic faults, volcanoes, landslides) at a spatial resolution of less than 100 m and cm-level precision. Permanent Scatterers SAR Interferometry method (PSInSARTM) has been introduced by Politecnico of Milano as an advanced InSAR technique capable of measuring millimetre scale displacements of individual radar targets on the ground by using multi-temporal data-sets, estimating and removing the atmospheric components. Other techniques (e.g. CTM) have followed similar strategies and have shown promising results in different scenarios. Different processing approaches have been adopted, according to data availability, characteristic of the area and dynamic characteristics of the volcano. Conventional DInSAR: Colima (Mexico), Nyiragongo (Congo), Pico (Azores), Areanal (Costa Rica) PSInSARTM: Piton de la Fournaise (La Reunion Island), Stromboli and Volcano (Italy), Hilo (Hawai), Mt. St. Helens (United States), CTM (Coherent Target Monitoring): Cumbre Vieja (La Palma) To generate products either Envisat ASAR, Radarsat 1or ALOS PALSAR data have been used. Surface Thermal Anomalies Volcanic hot-spots detection, radiant flux and effusion rate (where applicable) calculation of high temperature surface thermal anomalies such as active lava flow, strombolian activity, lava dome, pyroclastic flow and lava lake can be performed through MODIS (Terra / Aqua) MIR and TIR channels, or ASTER (Terra), HRVIR/HRGT (SPOT4/5) and Landsat family SWIR channels analysis. ASTER and Landsat TIR channels allow relative radiant flux calculation of low temperature anomalies such as lava and pyroclastic flow cooling, crater lake and low temperature fumarolic fields. MODIS, ASTER and SPOT data are processed to detect and measure the following volcanic surface phenomena: Effusive activity Piton de la Fournaise (Reunion Island); Mt Etna (Italy). Lava dome growths, collapses and related pyroclastic flows Soufrière Hills (Montserrat); Arenal - (Costa Rica). Permanent crater lake and ephemeral lava lake Karthala (Comores Islands). Strombolian activity Stromboli (Italy). Low temperature fumarolic fields Nisyros (Greece), Vulcano (Italy), Mauna Loa (Hawaii). Volcanic Emission The Volcanic Emission Service is provided to the users by a link to GSE-PROMOTE - Support to Aviation Control Service (SACS). The aim of the service is to deliver in near-real-time data derived from satellite measurements regarding SO2 emissions (SO2 vertical column density - Dobson Unit [DU]) possibly related to volcanic eruptions and to track the ash injected into the atmosphere during a volcanic eruption. SO2 measurements are derived from different satellite instruments, such as SCIAMACHY, OMI and GOME-2. The tracking of volcanic ash is accomplished by using SEVIRI-MSG data and, in particular, the following channels VIS 0.6 and IR 3.9, and along with IR8.7, IR 10.8 and IR 12.0. The GlobVolcano information system and its current experimentation represent a

Tampellini, Lucia; Ratti, Raffaella; Borgström, Sven; Seifert, Frank Martin; Peltier, Aline; Kaminski, Edouard; Bianchi, Marco; Branson, Wendy; Ferrucci, Fabrizio; Hirn, Barbara; van der Voet, Paul; van Geffen, J.

2010-05-01

350

Influence of fortnightly earth tides at Kilauea Volcano, Hawaii  

SciTech Connect

Analysis of 52 historic eruptions confirms the premise that fortnightly earth tides play a significant role in triggering activity at Kilauea Volcano, Hawaii. Since January 1832, nearly twice as many eruptions have occurred nearer fortnightly tidal maximum than tidal minimum (34 vs 18). A straightforward significance test indicates that the likelihood of a fortnightly tidal influence on Kilauea eruptions is roughly 90%. This is not the case for Mauna Loa Volcano, where 37 historic eruptions have been distributed randomly with respect to the fortnightly tide. At Kilauea, stresses induced by fortnightly earth tides presumably act in concert with volcanic and tectonic stresses to trigger shallow magma movements along preexisting zones of weakness. Differences in structure or internal plumbing may limit the effectiveness of this mechanism at Mauna Loa. Tidal effects seem to be less marked at shields than at some island-arc volcanoes, possibly because higher average volcanic stress rates in Hawaii more often override the effects of tidal stresses.

Dzurisin, D.

1980-11-01

351

Catalog of Earthquake Hypocenters at Alaskan Volcanoes: January 1 through December 31, 2007  

USGS Publications Warehouse

Between January 1 and December 31, 2007, AVO located 6,664 earthquakes of which 5,660 occurred within 20 kilometers of the 33 volcanoes monitored by the Alaska Volcano Observatory. Monitoring highlights in 2007 include: the eruption of Pavlof Volcano, volcanic-tectonic earthquake swarms at the Augustine, Illiamna, and Little Sitkin volcanic centers, and the cessation of episodes of unrest at Fourpeaked Mountain, Mount Veniaminof and the northern Atka Island volcanoes (Mount Kliuchef and Korovin Volcano). This catalog includes descriptions of : (1) locations of seismic instrumentation deployed during 2007; (2) earthquake detection, recording, analysis, and data archival systems; (3) seismic velocity models used for earthquake locations; (4) a summary of earthquakes located in 2007; and (5) an accompanying UNIX tar-file with a summary of earthquake origin times, hypocenters, magnitudes, phase arrival times, location quality statistics, daily station usage statistics, and all files used to determine the earthquake locations in 2007.

Dixon, James P.; Stihler, Scott D.; Power, John A.

2008-01-01

352

1994 Volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory  

USGS Publications Warehouse

During 1994, the Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, or false alarms at nine volcanic centers-- Mount Sanford, Iliamna, the Katmai group, Kupreanof, Mount Veniaminof, Shishaldin, Makushin, Mount Cleveland and Kanaga (table 1). Of these volcanoes, AVO has a real time, continuously recording seismic network only at Iliamna, which is located in the Cook Inlet area of south-central Alaska (fig. 1). AVO has dial-up access to seismic data from a 5-station network in the general region of the Katmai group of volcanoes. The remaining unmonitored volcanoes are located in sparsely populated areas of the Wrangell Mountains, the Alaska Peninsula, and the Aleutian Islands (fig. 1). For these volcanoes, the AVO monitoring program relies chiefly on receipt of pilot reports, observations of local residents and analysis of satellite imagery.

Neal, Christina A.; Doukas, Michael P.; McGimsey, Robert G.

1995-01-01

353

A single VLSI chip for computing syndromes in the (225, 223) Reed-Solomon decoder  

NASA Technical Reports Server (NTRS)

A description of a single VLSI chip for computing syndromes in the (255, 223) Reed-Solomon decoder is presented. The architecture that leads to this single VLSI chip design makes use of the dual basis multiplication algorithm. The same architecture can be applied to design VLSI chips to compute various kinds of number theoretic transforms.

Hsu, I. S.; Truong, T. K.; Shao, H. M.; Deutsch, L. J.

1986-01-01

354

Sea surface salinity and temperature seasonal changes in the Solomon and Bismarck Seas  

NASA Astrophysics Data System (ADS)

Small SST and SSS (an indicator of iron-rich Papua New Guinea river outflows) changes in the Solomon and Bismarck Seas may be transported to the equatorial Pacific and have strong climatic and biological impacts. We analyze mean and seasonal change of SST and SSS in the Solomon and Bismarck Seas, using 1977-2009 in situ data collected from Voluntary Observing Ships. Co-variability of these two variables with surface wind, altimeter-derived current anomalies, precipitation, and Sepik river discharge is examined. SST and SSS show large annual oscillations in the Solomon Sea, with the coldest and saltiest waters occurring in July/August mainly due to horizontal advection. In contrast, they show large semi-annual oscillations in the Bismarck Sea. There, the coldest and saltiest waters happen in January/February, when the northwest monsoon winds drive coastal upwelling, and in July/August, when the New Guinea Coastal Current advects cold and high-salinity waters from the Solomon Sea through Vitiaz Strait. The low SSS values observed in April/May, stuck between the two SSS maxima, are further enhanced by the Sepik river discharge annual maximum. A high-resolution model strengthens the conclusions we derive from observations. The impacts of ENSO on SST and SSS are also discussed.

Delcroix, Thierry; Radenac, Marie-Helene; Cravatte, Sophie; Gourdeau, Lionel; Alory, Gael

2014-05-01

355

JOURNAL ARTICLES Solomon, J., Kumar, R. and Alvi, F. S. "High Bandwidth Pulsed Microactuators for  

E-print Network

JOURNAL ARTICLES Solomon, J., Kumar, R. and Alvi, F. S. "High Bandwidth Pulsed Microactuators for High Speed Flow Control," AIAA Journal , Vol. 48, No. 10, pp. 2386-2396, October 2010. Venkatkrishnan with Microjet Control," to appear in the AIAA Journal, accepted, anticipated publication, early Spring 2011

356

Appropriate storage for high-penetration grid-connected photovoltaic plants A.A. Solomon a  

E-print Network

Appropriate storage for high-penetration grid-connected photovoltaic plants A.A. Solomon a , D o Article history: Received 5 April 2011 Accepted 10 October 2011 Keywords: Photovoltaics Energy storage size and its related properties for matching very large photovoltaic plants to the grid; and what

Kammen, Daniel M.

357

Development of a Multiplexed Coaxial Pulsed Plasma Darren M. King, Wayne C. Solomon, David L. Carroll  

E-print Network

1 Development of a Multiplexed Coaxial Pulsed Plasma Thruster Darren M. King, Wayne C. Solomon in the boron nitride exit nozzle, which also forms the exit seal. A central electrode resides in a boron nitride insulator to form the rear seal of the thruster. The energy storage unit (ESU) comprises two 7-cap

Carroll, David L.

358

A VLSI Reed-Solomon decoder architecture for concatenate-coded space and spread spectrum communications  

NASA Technical Reports Server (NTRS)

In this paper, a VLSI Reed-Solomon (RS) decoder architecture for concatenate-coded space and spread spectrum communications, is presented. The known decoding procedures for RS codes are exploited and modified to obtain a repetitive and recursive decoding technique which is suitable for VLSI implementation and pipeline processing.

Liu, K. Y.

1983-01-01

359

Numerical simulation of tsunami generation by pryoclastic flow at Aniakchak Volcano, Alaska  

USGS Publications Warehouse

Pyroclastic flows entering the sea are plausible mechanisms for tsunami generation at volcanic island arcs worldwide. We evaluate tsunami generation by pyroclastic flow using an example from Aniakchak volcano in Alaska where evidence for tsunami inundation coincident with a major, caldera-forming eruption of the volcano ca. 3.5 ka has been described. Using a numerical model, we simulate the tsunami and compare the results to field estimates of tsunami run up.

Waythomas, C.F.; Watts, P.

2003-01-01

360

Mt. Erebus: A Surprising Volcano: Grades 2-3:Electronic Book  

NSDL National Science Digital Library

This informational text introduces students to Mt. Erebus, a volcano located on Ross Island, just off the coast of Antarctica. Mt. Erebus is the world's southernmost active volcano. The text is written at a grade two through grade three reading level. This is an onscreen version that contains recorded narration allowing students to listen to the text as they read along. Highlighted vocabulary words have individually recorded definitions heard by clicking on the links.

Fries-Gaither, Jessica

361

The Big Island of Hawaii  

NASA Technical Reports Server (NTRS)

Boasting snow-covered mountain peaks and tropical forest, the Island of Hawaii, the largest of the Hawaiian Islands, is stunning at any altitude. This false-color composite (processed to simulate true color) image of Hawaii was constructed from data gathered between 1999 and 2001 by the Enhanced Thematic Mapper plus (ETM+) instrument, flying aboard the Landsat 7 satellite. The Landsat data were processed by the National Oceanographic and Atmospheric Administration (NOAA) to develop a landcover map. This map will be used as a baseline to chart changes in land use on the islands. Types of change include the construction of resorts along the coastal areas, and the conversion of sugar plantations to other crop types. Hawaii was created by a 'hotspot' beneath the ocean floor. Hotspots form in areas where superheated magma in the Earth's mantle breaks through the Earth's crust. Over the course of millions of years, the Pacific Tectonic Plate has slowly moved over this hotspot to form the entire Hawaiian Island archipelago. The black areas on the island (in this scene) that resemble a pair of sun-baked palm fronds are hardened lava flows formed by the active Mauna Loa Volcano. Just to the north of Mauna Loa is the dormant grayish Mauna Kea Volcano, which hasn't erupted in an estimated 3,500 years. A thin greyish plume of smoke is visible near the island's southeastern shore, rising from Kilauea-the most active volcano on Earth. Heavy rainfall and fertile volcanic soil have given rise to Hawaii's lush tropical forests, which appear as solid dark green areas in the image. The light green, patchy areas near the coasts are likely sugar cane plantations, pineapple farms, and human settlements. Courtesy of the NOAA Coastal Services Center Hawaii Land Cover Analysis project

2002-01-01

362

Geology of Kilauea volcano  

SciTech Connect

This paper summarizes studies of the structure, stratigraphy, petrology, drill holes, eruption frequency, and volcanic and seismic hazards of Kilauea volcano. All the volcano is discussed, but the focus is on its lower east rift zone (LERZ) because active exploration for geothermal energy is concentrated in that area. Kilauea probably has several separate hydrothermal-convection systems that develop in response to the dynamic behavior of the volcano and the influx of abundant meteoric water. Important features of some of these hydrothermal-convection systems are known through studies of surface geology and drill holes. Observations of eruptions during the past two centuries, detailed geologic mapping, radiocarbon dating, and paleomagnetic secular-variation studies indicate that Kilauea has erupted frequently from its summit and two radial rift zones during Quaternary time. Petrologic studies have established that Kilauea erupts only tholeiitic basalt. Extensive ash deposits at Kilauea's summit and on its LERZ record locally violent, but temporary, disruptions of local hydrothermal-convection systems during the interaction of water or steam with magma. Recent drill holes on the LERZ provide data on the temperatures of the hydrothermal-convection systems, intensity of dike intrusion, porosity and permeability, and an increasing amount of hydrothermal alteration with depth. The prehistoric and historic record of volcanic and seismic activity indicates that magma will continue to be supplied to deep and shallow reservoirs beneath Kilauea's summit and rift zones and that the volcano will be affected by eruptions and earthquakes for many thousands of years. 71 refs., 2 figs.

Moore, R.B. (Geological Survey, Denver, CO (United States). Federal Center); Trusdell, F.A. (Geological Survey, Hawaii National Park, HI (United States). Hawaiian Volcano Observatory)

1993-08-01

363

The Three Little Volcanoes  

NSDL National Science Digital Library

In this worksheet students identify and label the characteristic features of shield, cinder cone and composite volcanoes. The resource is part of the teacher's guide accompanying the video, NASA Why Files: The Case of the Mysterious Red Light. Lesson objectives supported by the video, additional resources, teaching tips and an answer sheet are included in the teacher's guide.

364

Santa Maria Volcano, Guatemala  

NASA Technical Reports Server (NTRS)

The eruption of Santa Maria volcano in 1902 was one of the largest eruptions of the 20th century, forming a large crater on the mountain's southwest flank. Since 1922, a lava-dome complex, Santiaguito, has been forming in the 1902 crater. Growth of the dome has produced pyroclastic flows as recently as the 2001-they can be identified in this image. The city of Quezaltenango (approximately 90,000 people in 1989) sits below the 3772 m summit. The volcano is considered dangerous because of the possibility of a dome collapse such as one that occurred in 1929, which killed about 5000 people. A second hazard results from the flow of volcanic debris into rivers south of Santiaguito, which can lead to catastrophic flooding and mud flows. More information on this volcano can be found at web sites maintained by the Smithsonian Institution, Volcano World, and Michigan Tech University. ISS004-ESC-7999 was taken 17 February 2002 from the International Space Station using a digital camera. The image is provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Searching and viewing of additional images taken by astronauts and cosmonauts is available at the NASA-JSC Gateway to

2002-01-01

365

The Super Volcano Game  

NSDL National Science Digital Library

How would you handle a volcano diasater? In this game, you've just been appointed chief of the Emergency Management Agency for Bluebear County. Everyone is counting on you to handle the eruption of Mount Spur. Download this game to find out. Before you play, make sure Flash is installed on your computer.

Corporation, British B.

366

The Volcano Adventure Guide  

NASA Astrophysics Data System (ADS)

This guide contains vital information for anyone wishing to visit, explore, and photograph active volcanoes safely and enjoyably. Following an introduction that discusses eruption styles of different types of volcanoes and how to prepare for an exploratory trip that avoids volcanic dangers, the book presents guidelines to visiting 42 different volcanoes around the world. It is filled with practical information that includes tour itineraries, maps, transportation details, and warnings of possible non-volcanic dangers. Three appendices direct the reader to a wealth of further volcano resources in a volume that will fascinate amateur enthusiasts and professional volcanologists alike. Rosaly Lopes is a planetary geology and volcanology specialist at the NASA Jet Propulsion Laboratory in California. In addition to her curatorial and research work, she has lectured extensively in England and Brazil and written numerous popular science articles. She received a Latinas in Science Award from the Comision Feminil Mexicana Nacional in 1991 and since 1992, has been a co-organizer of the United Nations/European Space Agency/The Planetary Society yearly conferences on Basic Science for the Benefit of Developing Countries.

Lopes, Rosaly

2005-02-01

367

Synthesizing knowledge of ocean islands  

NASA Astrophysics Data System (ADS)

AGU Chapman Conference on the Galápagos as a Laboratory for the Earth Sciences; Puerto Ayora, Galápagos, Ecuador, 25-30 July 2011 An inspiration for Darwin's theory of evolution, the Galápagos Islands and surrounding waters are a natural laboratory for a wide range of Earth science topics. The Galápagos are perfectly situated for geophysical and geochemical investigations of deep-Earth processes at a hot spot, and proximity to a spreading center allows exploration of hot spot-ridge interactions. Several highly active volcanoes show rapid deformation facilitating investigation of melt transport paths and volcanic structure. The islands exhibit a range of ages, eruptive styles, and climatic zones that allow analysis of hydrogeologic and geomorphic processes. The Galápagos Islands are a World Heritage Site and are an ideal setting for developing an integrated biological and geological understanding of ocean island evolution.

Jefferson, Anne J.; Lees, Jonathan M.; McClinton, Tim

2011-11-01

368

Long-term eruptive activity at a submarine arc volcano  

USGS Publications Warehouse

Three-quarters of the Earth's volcanic activity is submarine, located mostly along the mid-ocean ridges, with the remainder along intraoceanic arcs and hotspots at depths varying from greater than 4,000 m to near the sea surface. Most observations and sampling of submarine eruptions have been indirect, made from surface vessels or made after the fact. We describe here direct observations and sampling of an eruption at a submarine arc volcano named NW Rota-1, located 60 km northwest of the island of Rota (Commonwealth of the Northern Mariana Islands). We observed a pulsating plume permeated with droplets of molten sulphur disgorging volcanic ash and lapilli from a 15-m diameter pit in March 2004 and again in October 2005 near the summit of the volcano at a water depth of 555 m (depth in 2004). A turbid layer found on the flanks of the volcano (in 2004) at depths from 700 m to more than 1,400 m was probably formed by mass-wasting events related to the eruption. Long-term eruptive activity has produced an unusual chemical environment and a very unstable benthic habitat exploited by only a few mobile decapod species. Such conditions are perhaps distinctive of active arc and hotspot volcanoes. ?? 2006 Nature Publishing Group.

Embley, R. W.; Chadwick, Jr. , W. W.; Baker, E. T.; Butterfield, D. A.; Resing, J. A.; De Ronde, C. E. J.; Tunnicliffe, V.; Lupton, J. E.; Juniper, S. K.; Rubin, K. H.; Stern, R. J.; Lebon, G. T.; Nakamura, K. -I.; Merle, S. G.; Hein, J. R.; Wiens, D. A.; Tamura, Y.

2006-01-01

369

Paleomagnetism of San Cristobal Island, Galapagos  

USGS Publications Warehouse

Isla San Cristobal, the most easterly of the Galapagos Islands, consists of two parts: a large volcano constitutes the southwest half of the island and an irregular apron of small cones and flows makes up the northeast half. As some of the younger flows on the flanks of the large volcano are reversely magnetized, the minimum age of the volcano is 0.7 my, which is the age of the Brunhes-Matuyama reversal boundary. The true age is probably several times greater. The cones and flows to the northeast are all normally magnetized. The between-site angular dispersion of virtual poles is 11.3?? - a value consistent with mathematical models for the latitude dependence of geomagnetic secular variation. ?? 1971.

Cox, A.

1971-01-01

370

Hydrothermal reservoir beneath Taal Volcano (Philippines): Implications to volcanic activity  

NASA Astrophysics Data System (ADS)

Taal Volcano is one of the most active volcanoes in the Philippines. The first recorded eruption was in 1573. Since then it has erupted 33 times resulting in thousands of casualties and large damages to property. In 1995, it was declared as one of the 15 Decade Volcanoes. Beginning in the early 1990s it has experienced several phases of abnormal activity, including seismic swarms, episodes of ground deformation, ground fissuring and hydrothermal activities, which continues up to the present. However, it has been noted that past historical eruptions of Taal Volcano may be divided into 2 distinct cycles, depending on the location of the eruption center, either at Main Crater or at the flanks. Between 1572-1645, eruptions occurred at the Main Crater, in 1707 to 1731, they occurred at the flanks. In 1749, eruptions moved back to the Main Crater until 1911. During the 1965 and until the end of the 1977 eruptions, eruptive activity once again shifted to the flanks. As part of the PHIVOLCS-JICA-SATREPS Project magnetotelluric and audio-magnetotelluric surveys were conducted on Volcano Island in March 2011 and March 2012. Two-dimensional (2-D) inversion and 3-D forward modeling reveals a prominent and large zone of relatively high resistivity between 1 to 4 kilometers beneath the volcano almost directly beneath the Main Crater, surrounded by zones of relatively low resistivity. This anomalous zone of high resistivity is hypothesized to be a large hydrothermal reservoir filled with volcanic fluids. The presence of this large hydrothermal reservoir could be related to past activities of Taal Volcano. In particular we believe that the catastrophic explosion described during the 1911 eruption was the result of the hydrothermal reservoir collapsing. During the cycle of Main Crater eruptions, this hydrothermal reservoir is depleted, while during a cycle of flank eruptions this reservoir is replenished with hydrothermal fluids.

Nagao, T.; Alanis, P. B.; Yamaya, Y.; Takeuchi, A.; Bornas, M. V.; Cordon, J. M.; Puertollano, J.; Clarito, C. J.; Hashimoto, T.; Mogi, T.; Sasai, Y.

2012-12-01

371

Submarine landslides in French Polynesia SUBMARINE LANDSLIDES IN SOCIETY AND AUSTRAL ISLANDS,  

E-print Network

Submarine landslides in French Polynesia 1 SUBMARINE LANDSLIDES IN SOCIETY AND AUSTRAL ISLANDS with the age of oceanic islands. Submarine active volcanoes are subject to superficial landslides of fragmental material whereas young islands exhibit marks of mass wasting corresponding to giant lateral collapses due

Clouard, Valerie

372

Multiparameter Volcano Surveillance of Villarrica Volcano (South-Central Chile)  

NASA Astrophysics Data System (ADS)

Villarrica is one of the most active volcanoes in Chile and one of the few in the world known to have an active lava lake within its crater. This snow-covered volcano generates frequent strombolian eruptions and lava flows and, at times, the melting of snow can cause massive lahars. Besides this, continuous degassing and high-level seismicity are the most common types of activity recorded at the volcano. In order to investigate the mechanisms driving the persistent degassing and seismic activity at the volcano, we use a multiparameter approach based on the combined study of high time-resolved gas and seismic data. These data are respectively acquired by means of 3 stationary NOVAC-type scanning Mini-DOAS and 7 additional seismometers (short period and broad bands), installed at the volcano since March 2009, that complement the existing OVDAS (Observatorio Volcanológico de los Andes del Sur) volcano monitoring network. On the basis of the combination of gas and seismological measurements we aim at gaining insight into volcano-magmatic processes, and factors playing a role on onset of volcanic unrest and eruptive activity. Since the gas monitoring network has been installed at the volcano a correlation between SO2 emissions and seismic activity (LP events) has been recognized. A possible role played by regional tectonics on detected changes in volcano degassing and seismicity, and consequently on the volcanic activity, is also investigated.

Garofalo, Kristin; Peña, Paola; Dzierma, Yvonne; Hansteen, Thor; Rabbel, Wolfgang; Gil, Fernando

2010-05-01

373

Bulk rock composition and geochemistry of olivine-hosted melt inclusions in the Grey Porri Tuff and selected lavas of the Monte dei Porri volcano, Salina, Aeolian Islands, southern Italy  

USGS Publications Warehouse

The Aeolian Islands are an arcuate chain of submarine seamounts and volcanic islands, lying just north of Sicily in southern Italy. The second largest of the islands, Salina, exhibits a wide range of compositional variation in its erupted products, from basaltic lavas to rhyolitic pumice. The Monte dei Porri eruptions occurred between 60 ka and 30 ka, following a period of approximately 60,000 years of repose. The bulk rock composition of the Monte dei Porri products range from basaltic-andesite scoria to andesitic pumice in the Grey Porri Tuff (GPT), with the Monte dei Porri lavas having basaltic-andesite compositions. The typical mineral assemblage of the GPT is calcic plagioclase, clinopyroxene (augite), olivine (Fo72?84) and orthopyroxene (enstatite) ± amphibole and Ti-Fe oxides. The lava units show a similar mineral assemblage, but contain lower Fo olivines (Fo57?78). The lava units also contain numerous glomerocrysts, including an unusual variety that contains quartz, K-feldspar and mica. Melt inclusions (MI) are ubiquitous in all mineral phases from all units of the Monte dei Porri eruptions; however, only data from olivine-hosted MI in the GPT are reported here. Compositions of MI in the GPT are typically basaltic (average SiO2 of 49.8 wt %) in the pumices and basaltic-andesite (average SiO2 of 55.6 wt %) in the scoriae and show a bimodal distribution in most compositional discrimination plots. The compositions of most of the MI in the scoriae overlap with bulk rock compositions of the lavas. Petrological and geochemical evidence suggest that mixing of one or more magmas and/or crustal assimilation played a role in the evolution of the Monte dei Porri magmatic system, especially the GPT. Analyses of the more evolved mineral phases are required to better constrain the evolution of the magma.

Doherty, Angela L.; Bodnar, Robert J.; De Vivo, Benedetto; Bohrson, Wendy A.; Belkin, Harvey E.; Messina, Antonia; Tracy, Robert J.

2012-01-01

374

Fully Nonlinear Potential Flow Model of an Experimental Submerged Moored Structure Huan Lin, David Robinson, Solomon Yim*  

E-print Network

Robinson, Solomon Yim* Department of Civil Engineering, Oregon State University, Oregon, U.S.A. Katsuji effects of submerged moored systems conducted by researches at Oregon State University, a medium

Yim, Solomon C.

375

Earthquakes and Volcanoes  

NSDL National Science Digital Library

This unit provides an introduction for younger students on earthquakes, volcanoes, and how they are related. Topics include evidence of continental drift, types of plate boundaries, types of seismic waves, and how to calculate the distance to the epicenter of an earthquake. There is also information on how earthquake magnitude and intensity are measured, and how seismic waves can reveal the Earth's internal structure. A vocabulary list and downloadable, printable student worksheets are provided.

Medina, Philip

2011-06-27

376

Yellowstone Volcano Observatory  

NSDL National Science Digital Library

This is the homepage of the United States Geological Survey's (USGS) Yellowstone Volcano Observatory. It features news articles, monitoring information, status reports and information releases, and information on the volcanic history of the Yellowstone Plateau Volcanic Field. Users can access monthly updates with alert levels and aviation warning codes and real-time data on ground deformation, earthquakes, and hydrology. There is also a list of online products and publications, and an image gallery.

2012-08-23

377

Volcanoes and Climate Change  

NSDL National Science Digital Library

Major volcanic eruptions alter the Earth's radiative balance, as volcanic ash and gas clouds absorb terrestrial radiation and scatter a significant amount of the incoming solar radiation, an effect known as "radiative forcing" that can last from two to three years following a volcanic eruption. This results in reduced temperatures in the troposphere, and changes in atmospheric circulation patterns. This site uses text, photographs, and links to related sites to describe volcano-induced climate change.

378

Gelatin Volcanoes: Student Page  

NSDL National Science Digital Library

This is the Student Page of an activity that teaches students how and why magma moves inside volcanoes by injecting colored water into a clear gelatin cast. The Student Page contains the activity preparation instructions and materials list, key words, and a photograph of the experimental setup. There is also an extension activity question that has students predict what will happen when the experiment is run using an elongated model. This activity is part of Exploring Planets in the Classroom's Volcanology section.

379

Cancer epidemiology in the pacific islands - past, present and future.  

PubMed

The Pacific Ocean contains approximately 25,000 islands, stretching from Papua New Guinea to Easter Island, populated by mixtures of Melanesians, Micronesians and Polynesians, as well as migrant groups from Asia and Europe. The region encompasses a third of the surface of the earth although it is sparsely populated at a total of around 9 million. With the exception of some of the more populated islands, such as New Zealand and Hawaii, few surveys of chronic diseases have been conducted, but it is increasingly recognized that obesity, diabetes and associated conditions are emerging public health problems and clearly there is a need for cooperation to optimize control. Here we focus on cancer registry and epidemiological findings for Papua New Guinea, the Solomons, Vanuatu, Samoa, New Caledonia, Fiji, Polynesia, French Polynesia, Maori in New Zealand, Native Hawaiians, Micronesia, including Guam, and Aboriginal populations in Australia as assessed by PubMed searches and perusal of the International Agency for Cancer Research descriptive epidemiology database. Overall, the major cancers in males are oral and liver in Papua New Guinea and the Solomon Islands, and lung and prostate elsewhere (Fiji being exceptional in demonstrating a predominance of esophageal cancer), whereas in females it is breast and either cervix or lung, depending largely on whether cervical cancer screening program is active. In certain locations thyroid cancer is also very prevalent in females. The similarities and variation point to advantages for collaborative research to provide the evidence-base for effective cancer control programs in the region. PMID:20553071

Moore, Malcolm A; Baumann, Francine; Foliaki, Sunia; Goodman, Marc T; Haddock, Robert; Maraka, Roger; Koroivueta, Josefa; Roder, David; Vinit, Thomas; Whippy, Helen J D; Sobue, Tomotaka

2010-01-01

380

Narrative Tension in I Kings I-II: A Study of the Structural and Thematic Unity of the Solomonic Narrative  

Microsoft Academic Search

During the past century, historical-critical scholarship on the reign of Solomon (I Kings I-II) has advanced the argument that the narrative is a heterogeneous mix of material, originating from diverse socio-historical settings. Reasonably enough, critical research on the Solomon narrative has concentrated on a number of compositional or redactional questions. The result of this research, however, is that the narrative

Kim Ian Parker

1988-01-01

381

Narrative tension in I Kings 1--11: A study of the structural and thematic unity of the Solomonic narrative  

Microsoft Academic Search

During the past century, historical-critical scholarship on the reign of Solomon (I Kings 1-11) has advanced the argument that the narrative is a heterogeneous mix of material, originating from diverse socio-historical settings. Reasonably enough, critical research on the Solomon narrative has concentrated on a number of compositional or redactional questions. The result of this research, however, is that the narrative

Kim Ian Parker

1988-01-01

382

Volcanoes generate devastating waves  

SciTech Connect

Although volcanic eruptions can cause many frightening phenomena, it is often the power of the sea that causes many volcano-related deaths. This destruction comes from tsunamis (huge volcano-generated waves). Roughly one-fourth of the deaths occurring during volcanic eruptions have been the result of tsunamis. Moreover, a tsunami can transmit the volcano's energy to areas well outside the reach of the eruption itself. Some historic records are reviewed. Refined historical data are increasingly useful in predicting future events. The U.S. National Geophysical Data Center/World Data Center A for Solid Earth Geophysics has developed data bases to further tsunami research. These sets of data include marigrams (tide gage records), a wave-damage slide set, digital source data, descriptive material, and a tsunami wall map. A digital file contains information on methods of tsunami generation, location, and magnitude of generating earthquakes, tsunami size, event validity, and references. The data can be used to describe areas mot likely to generate tsunamis and the locations along shores that experience amplified effects from tsunamis.

Lockridge, P. (National Geophysical Data Center, Boulder, CO (USA))

1988-01-01

383

Pairing the Volcano  

E-print Network

Isogeny volcanoes are graphs whose vertices are elliptic curves and whose edges are $\\ell$-isogenies. Algorithms allowing to travel on these graphs were developed by Kohel in his thesis (1996) and later on, by Fouquet and Morain (2001). However, up to now, no method was known, to predict, before taking a step on the volcano, the direction of this step. Hence, in Kohel's and Fouquet-Morain algorithms, many steps are taken before choosing the right direction. In particular, ascending or horizontal isogenies are usually found using a trial-and-error approach. In this paper, we propose an alternative method that efficiently finds all points $P$ of order $\\ell$ such that the subgroup generated by $P$ is the kernel of an horizontal or an ascending isogeny. In many cases, our method is faster than previous methods. This is an extended version of a paper published in the proceedings of ANTS 2010. In addition, we treat the case of 2-isogeny volcanoes and we derive from the group structure of the curve and the pairing ...

Ionica, Sorina

2011-01-01

384

Sulfur volcanoes on Io?  

NASA Technical Reports Server (NTRS)

The unusual rheological properties of sulfur are discussed in order to determine the distinctive volcanic flow morphologies which indicate the presence of sulfur volcanoes on the Saturnian satellite Io. An analysis of high resolution Voyager imagery reveals three features which are considered to be possible sulfur volcanoes: Atar Patera, Daedalus Patera, and Kibero Patera. All three features are distinguished by circular-to-oval central masses surrounded by irregular widespread flows. The central zones of the features are interpreted to be domes formed of high temperature sulfur. To confirm the interpretations of the satellite data, molten sulfur was extruded in the laboratory at a temperature of 210 C on a flat surface sloping 0.5 deg to the left. At this temperature, the sulfur formed a viscous domelike mass over the event. As parts of the mass cooled to 170 C the viscosity decreased to a runny stage, forming breakout flows. It is concluded that a case can be made for sulfur volcanoes on Io sufficient to warrant further study, and it is recommended that the upcoming Galileo mission examine these phenomena.

Greeley, R.; Fink, J. H.

1984-01-01

385

Cascades Volcano Observatory: Educational Outreach  

NSDL National Science Digital Library

Located in Vancouver, Washington, the Cascades Volcano Observatory monitors and reports on volcanic activity in the area and around the country. The related Educational Outreach Web site is provided by the US Geological Survey. Visitors will find information on current volcanic activity and news, what to do if a volcano erupts, volcano terminology, America's volcanic history, how the Cascade range got their names, volcano questions and answers, and much more. Other features of the site include activities and fun "stuff," posters and videos, and many outside links.

386

On the binary weight distribution of some Reed-Solomon codes  

NASA Technical Reports Server (NTRS)

Consider an (n,k) linear code with symbols from GF(2 sup M). If each code symbol is represented by a m-tuple over GF(2) using certain basis for GF(2 sup M), a binary (nm,km) linear code is obtained. The weight distribution of a binary linear code obtained in this manner is investigated. Weight enumerators for binary linear codes obtained from Reed-Solomon codes over GF(2 sup M) generated by polynomials, (X-alpha), (X-l)(X-alpha), (X-alpha)(X-alpha squared) and (X-l)(X-alpha)(X-alpha squared) and their extended codes are presented, where alpha is a primitive element of GF(2 sup M). Binary codes derived from Reed-Solomon codes are often used for correcting multiple bursts of errors.

Lin, S.

1985-01-01

387

An evaluation of selenium concentrations in water, sediment, invertebrates, and fish from the Solomon River Basin  

Microsoft Academic Search

The Solomon River Basin is located in north-central Kansas in an area underlain by marine geologic shales. Selenium is an\\u000a indigenous constituent of these shales and is readily leached into the surrounding groundwater. Portions of the Basin are\\u000a irrigated primarily through the pumping of selenium-contaminated groundwater from wells onto fields in agricultural production.\\u000a Water, sediment, macroinvertebrates, and fish were collected

Thomas W. May; James F. Fairchild; Jim D. Petty; Michael J. Walther; Jeff Lucero; Mike Delvaux; Jill Manring; Mike Armbruster

2008-01-01

388

A Reed-Solomon Product-Code (RS-PC) decoder for DVD applications  

Microsoft Academic Search

The digital versatile disk (DVD), an emerging standard of optical storage, provides a higher capacity than audio CD, CD-ROM or video CD (VCD). To mitigate the errors introduced during manufacturing or by user damage, a Reed-Solomon Product-Code (RS-PC) is used in DVD for error correction. For this application, the authors present an RS-PC decoder chip with a dual-frame-buffer architecture. The

H. C. Chang; C. Shung

1998-01-01

389

The fast decoding of Reed-Solomon codes using Fermat theoretic transforms and continued fractions  

NASA Technical Reports Server (NTRS)

It is shown that Reed-Solomon (RS) codes can be decoded by using a fast Fourier transform (FFT) algorithm over finite fields GF(F sub n), where F sub n is a Fermat prime, and continued fractions. This new transform decoding method is simpler than the standard method for RS codes. The computing time of this new decoding algorithm in software can be faster than the standard decoding method for RS codes.

Reed, I. S.; Scholtz, R. A.; Welch, L. R.; Truong, T. K.

1978-01-01

390

The fast decoding of Reed-Solomon codes using fermat theoretic transforms and continued fractions  

NASA Technical Reports Server (NTRS)

It is shown that Reed-Solomon (RS) codes can be decoded by using a fast Fourier transform algorithm over finite fields GF(F sub n) where F sub n is a Fermat prime, and continued fractions. This new transform decoding method is simpler than the standard method for RS codes. The computing time of this new decoding algorithm in software can be faster than the standard decoding method for RS codes.

Welch, L. R.; Reed, I. S.; Truong, T. K.

1976-01-01

391

SEU hardened memory cells for a CCSDS Reed-Solomon encoder  

NASA Technical Reports Server (NTRS)

A design technique to harden CMOS memory circuits against single event upset (SEU) in the space environment is reported. The design technique provides a recovery mechanism which is independent of the shape of the upsetting event. A RAM cell and flip-flop design are presented to demonstrate the method. The flip-flop was used in the control circuitry for a Reed-Solomon encoder designed for the Space Station and Explorer platforms.

Whitaker, Sterling; Canaris, John; Liu, Kathy

1991-01-01

392

Traumatic and Healing Memory in Leslie Marmon Silko's Ceremony and Toni Morrison's Song of Solomon  

Microsoft Academic Search

A comparative analysis of Leslie Marmon Silko’s Ceremony and Toni Morrison’s Song of Solomon, with a focus on individual as well as collective memory work in historically marginalized indigenous and African-American communities, respectively. This represents a critical study of how the novels invoke progressive and redemptive models of remembering, as well as foreground the role of spiritual guides in the

Ambata K Kazi-Nance

2012-01-01

393

A Tutorial on Reed-Solomon Coding for Fault-Tolerance in RAID-Like Systems  

Microsoft Academic Search

It is well-known that Reed-Solomon codes may be used to provide error correction for multiple failures in RAID- like systems. The coding technique itself, however, is not as well-known. To the coding theorist, this technique is a straightforward extension to a basic coding paradigm and needs no special mention. However, to the systems programmer with no training in coding theory,

James S. Plank

1997-01-01

394

A Reed-Solomon coding\\/decoding structure for an ADSL modem  

Microsoft Academic Search

The performance of the Reed Solomon coder\\/decoder for an ADSL modem is studied. The proposal incorporates a new faster parallel structure for the RS coding\\/decoding part of the modem that exploits the single latency operation of the device. The modem is fully compatible with the existing standard of T1E1.4 ANSI Standard Group and ADSL Forum requirements. The proposed structure was

V. Stylianakis; S. Toptchiyski

1999-01-01

395

Turbo encoding and decoding of Reed-Solomon codes through binary decomposition and self-concatenation  

Microsoft Academic Search

This paper presents a two-stage turbo-coding scheme for Reed-Solomon (RS) codes through binary decomposition and self-concatenation. In this scheme, the binary image of an RS code over GF(2m) is first decomposed into a set of binary component codes with relatively small trellis complexities. Then the RS code is formatted as a self-concatenated code with itself as the outer code and

Cathy Ye Liu; Shu Lin

2004-01-01

396

Algebraic Soft-Decision Decoding of Reed-Solomon Codes Using Bit-level Soft Information  

Microsoft Academic Search

The performance of algebraic soft-decision decoding of Reed-Solomon codes using bit-level soft information is investigated. Optimal multiplicity assignment strategie s of algebraic soft-decision decoding with infinite cost are first studied over erasure channels and the binary symmetric channel. The corresponding decoding radii are calculated in closed forms and tight bounds on the error probability are derived. The multiplicity assignment strategy

Jing Jiang; Krishna R. Narayanan

2006-01-01

397

Contributions and applications of Reed Solomon coding techniques as applied to space communications systems  

NASA Astrophysics Data System (ADS)

The Reed-Solomon (R-S) codeblocks are particularly well adapted to correcting error bursts and, when concatenated with a convolutional code, allow a gain of 7.5 dB. Attention is given to the application of R-S decoding to CCSDS recommendations in two types of architectures: (1) a programmable architecture of multiprocessors with bit rates of several hundred kbit/s and (2) a regular VLSI architectures for which 25 Mbit/s is initially anticipated.

Ferreol, M.; Pouille, E.

398

Perspective View of Umnak Island, Aleutian Islands, Alaska (#1)  

NASA Technical Reports Server (NTRS)

This image is a perspective view of Umnak Island, one of Alaska's Aleutian Islands. The active Okmok volcano appears in the center of the island.

The image was created by draping a Landsat 7 Thematic Mapper image over a digital elevation mosaic derived from Airsar data.

This work was conducted as part of a NASA-funded Alaska Digital Elevation Model Project at the Alaska Synthetic Aperture Radar Facility (ASF) at the University of Alaska Geophysical Institute in Fairbanks, Alaska.

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.

2001-01-01

399

Perspective View of Umnak Island, Aleutian Islands, Alaska (#2)  

NASA Technical Reports Server (NTRS)

This image is a perspective view of Umnak Island, one of Alaska's Aleutian Islands. The active Okmok volcano appears in the center of the island.

The image was created by draping a Landsat 7 Thematic Mapper image over a digital elevation mosaic derived from Airsar data.

This work was conducted as part of a NASA-funded Alaska Digital Elevation Model Project at the Alaska Synthetic Aperture Radar Facility (ASF) at the University of Alaska Geophysical Institute in Fairbanks, Alaska.

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.

2001-01-01

400

Self-assembly of a giant molecular solomon link from 30 subcomponents.  

PubMed

The synthesis of topologically complex structures, such as links and knots, is one of the current challenges in supramolecular chemistry. The so-called Solomon link consists of two doubly interlocked rings. Despite being a rather simple link from a topological point of view, only few molecular versions of this link have been described so far. Here, we report the quantitative synthesis of a giant molecular Solomon link from 30 subcomponents. The highly charged structure is formed by assembly of 12 cis-blocked Pt(2+) complexes, six Cu(+) ions, and 12 rigid N-donor ligands. Each of the two interlocked rings is composed of six repeating Pt(ligand) units, while the six Cu(+) ions connect the two rings. With a molecular weight of nearly 12?kDa and a diameter of 44.2?Å, this complex is the largest non-DNA-based Solomon link described so far. Furthermore, it represents a molecular version of a "stick link". PMID:25169128

Schouwey, Clément; Holstein, Julian J; Scopelliti, Rosario; Zhurov, Konstantin O; Nagornov, Konstantin O; Tsybin, Yury O; Smart, Oliver S; Bricogne, Gérard; Severin, Kay

2014-10-13

401

Multiscale dynamical analysis of a high-resolution numerical model simulation of the Solomon Sea circulation  

NASA Astrophysics Data System (ADS)

high 1/36° resolution numerical model is used to study the ocean circulation in the Solomon Sea. An evaluation of the model with (the few) available observation shows that the 1/36° resolution model realistically simulates the Solomon Sea circulations. The model notably reproduces the high levels of mesoscale eddy activity observed in the Solomon Sea. With regard to previous simulations at 1/12° resolution, the average eddy kinetic energy levels are increased by up to ˜30-40% in the present 1/36° simulation, and the enhancement extends at depth. At the surface, the eddy kinetic energy level is maximum in March-April-May and is minimum in December-January-February. The high subsurface variability is related to the variability of the western boundary current (New Guinea Coastal Undercurrent). Moreover, the emergence of submesoscales is clearly apparent in the present simulations. A spectral analysis is conducted in order to evidence and characterize the modeled submesoscale dynamics and to provide a spectral view of scales interactions. The corresponding spectral slopes show a strong consistency with the Surface Quasi-Geostrophic turbulence theory.

Djath, Bughsin'; Verron, Jacques; Melet, Angelique; Gourdeau, Lionel; Barnier, Bernard; Molines, Jean-Marc

2014-09-01

402

Sea surface temperature and salinity seasonal changes in the western Solomon and Bismarck Seas  

NASA Astrophysics Data System (ADS)

analyze mean and seasonal change of Sea Surface Temperature (SST) and Salinity (SSS) in the Solomon and Bismarck Seas, using 1977-2009 in situ data collected from Voluntary Observing Ships. Covariability of these two variables with surface wind, altimeter-derived and model-derived horizontal currents, precipitation, and Sepik River discharge are examined. SST and SSS show large annual oscillations in the Solomon Sea, with the coldest and saltiest waters occurring in July/August mainly due to horizontal advection. In contrast, they show large semiannual oscillations in the Bismarck Sea. There, the coldest and saltiest waters happen in January/February, when the northwest monsoon winds drive coastal upwelling, and in July/August, when the New Guinea Coastal Current advects cold and high-salinity waters from the Solomon Sea through Vitiaz Strait. The low SSS values observed in April/May, stuck between the January/February and July/August SSS maxima, are further enhanced by the Sepik River discharge annual maximum. A high-resolution model strengthens the conclusions we derive from observations. The impacts of ENSO on SST and SSS are also discussed with, for instance, saltier-than-average and fresher-than-average waters during the 2002-2003 El Niño and 2007-2008 La Niña, respectively.

Delcroix, Thierry; Radenac, Marie-Hélène; Cravatte, Sophie; Alory, Gaël.; Gourdeau, Lionel; Léger, Fabien; Singh, Awnesh; Varillon, David

2014-04-01

403

Measuring volcanic deformation of the Galapagos Islands with InSAR  

Microsoft Academic Search

Located off the coast of Ecuador in the Pacific Ocean, the Galapagos Islands are home to some of the most active volcanoes in the world. The island chain experienced seven eruptions since 1992 from four different volcanoes. Using interferometric synthetic aperture radar (InSAR) from ERS-1, ERS-2, Radarsat-1, and Envisat satellites from 1992 to 2010, we can measure deformation at all

S. Baker; F. Amelung; M. Bagnardi

2010-01-01

404

Remote sensing of Italian volcanos  

NASA Technical Reports Server (NTRS)

The results of a July 1986 remote sensing campaign of Italian volcanoes are reviewed. The equipment and techniques used to acquire the data are described and the results obtained for Campi Flegrei and Mount Etna are reviewed and evaluated for their usefulness for the study of active and recently active volcanoes.

Bianchi, R.; Casacchia, R.; Coradini, A.; Duncan, A. M.; Guest, J. E.; Kahle, A.; Lanciano, P.; Pieri, D. C.; Poscolieri, M.

1990-01-01

405

Space Radar Image of Taal Volcano, Philippines  

NASA Technical Reports Server (NTRS)

This is an image of Taal volcano, near Manila on the island of Luzon in the Philippines. The black area in the center is Taal Lake, which nearly fills the 30-kilometer-diameter (18-mile) caldera. The caldera rim consists of deeply eroded hills and cliffs. The large island in Taal Lake, which itself contains a crater lake, is known as Volcano Island. The bright yellow patch on the southwest side of the island marks the site of an explosion crater that formed during a deadly eruption of Taal in 1965. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on its 78th orbit on October 5, 1994. The image shows an area approximately 56 kilometers by 112 kilometers (34 miles by 68 miles) that is centered at 14.0 degrees north latitude and 121.0 degrees east longitude. North is toward the upper right of the image. The colors in this image were obtained using the following radar channels: red represents the L-band (horizontally transmitted and received); green represents the L-band (horizontally transmitted and vertically received); blue represents the C-band (horizontally transmitted and vertically received). Since 1572, Taal has erupted at least 34 times. Since early 1991, the volcano has been restless, with swarms of earthquakes, new steaming areas, ground fracturing, and increases in water temperature of the lake. Volcanologists and other local authorities are carefully monitoring Taal to understand if the current activity may foretell an eruption. Taal is one of 15 'Decade Volcanoes' that have been identified by the volcanology community as presenting large potential hazards to population centers. The bright area in the upper right of the image is the densely populated city of Manila, only 50 kilometers (30 miles) north of the central crater. Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI), with the Deutsche Forschungsanstalt fuer Luft und Raumfahrt e.v.(DLR), the major partner in science, operations and data processing of X-SAR.

1994-01-01

406

The weathering and element fluxes from active volcanoes to the oceans: a Montserrat case study  

Microsoft Academic Search

The eruptions of the Soufrière Hills volcano on Montserrat (Lesser Antilles) from 1995 to present have draped parts of the\\u000a island in fresh volcaniclastic deposits. Volcanic islands such as Montserrat are an important component of global weathering\\u000a fluxes, due to high relief and runoff and high chemical and physical weathering rates of fresh volcaniclastic material. We\\u000a examine the impact of

Morgan T. Jones; Deborah J. Hembury; Martin R. Palmer; Bill Tonge; W. George Darling; Susan C. Loughlin

2011-01-01

407

Volcano Homework Assignment  

NSDL National Science Digital Library

In this and similar assignments students have to download quantitative natural hazard data from the Internet, load it into a spreadsheet, rank order the data, calculate recurrence times and plot the result on a log-log graph. They then interpret this graph in terms of the recurrence time of hazard events of different sizes. In many cases this includes comparing results from two different features (volcanoes, faults, rivers, etc.) Uses online and/or real-time data Addresses student fear of quantitative aspect and/or inadequate quantitative skills Uses geophysics to solve problems in other fields Addresses student misconceptions

Jaume, Steven

408

Validation and Analysis of SRTM and VCL Data Over Tropical Volcanoes  

NASA Technical Reports Server (NTRS)

The focus of our investigation was on the application of digital topographic data in conducting first-order volcanological and structural studies of tropical volcanoes, focusing on the Java, the Philippines and the Galapagos Islands. Kilauea volcano, Hawaii, served as our test site for SRTM data validation. Volcanoes in humid tropical environments are frequently cloud covered, typically densely vegetated and erode rapidly, so that it was expected that new insights into the styles of eruption of these volcanoes could be obtained from analysis of topographic data. For instance, in certain parts of the world, such as Indonesia, even the regional structural context of volcanic centers is poorly known, and the distribution of volcanic products (e.g., lava flows, pyroclastic flows, and lahars) are not well mapped. SRTM and Vegetation Canopy Lidar (VCL) data were expected to provide new information on these volcanoes. Due to the cancellation of the VCL mission, we did not conduct any lidar studies during the duration of this project. Digital elevation models (DEMs) such as those collected by SRTM provide quantitative information about the time-integrated typical activity on a volcano and allow an assessment of the spatial and temporal contributions of various constructional and destructional processes to each volcano's present morphology. For basaltic volcanoes, P_c?w!m-d and Garbed (2000) have shown that gradual slopes (less than 5 deg.) occur where lava and tephra pond within calderas or in the saddles between adjacent volcanoes, as well as where lava deltas coalesce to form coastal plains. Vent concentration zones (axes of rift zones) have slopes ranging from 10 deg. to 12 deg. Differential vertical growth rates between vent concentration zones and adjacent mostly-lava flanks produce steep constructional slopes up to 40". The steepest slopes (locally approaching 90 deg.) are produced by fluvial erosion, caldera collapse, faulting, and catastrophic avalanches, all of which are usually identifiable. Due to the delay in the release of the SRTM data following the February 2000 flight, a significant part of our effort was devoted to the analog studies of the SRTM topographic data using topographic data from airborne interferometric radars. As part of the original SRTM Science Team, we proposed four study sites (Kilauea, Hawaii; Mt. Pinatubo, Philippines; Cerro Am1 and Femandina volcanoes, Galapagos Islands; and Tengger caldera, Java) where we could conduct detailed geologic studies to evaluate the uses of SRTM data for the analysis of lava flows, lahars, erosion of ash deposits, and an evaluation of the structural setting of the volcanoes. Only near the end of this project was one of these SRTM Science Team products (Luzon Island, the Philippines) released to the community, and we only had limited time to work on these data.

Mouginis-Mark, Peter J.

2004-01-01

409

Eruptive fracture location forecasts from high-frequency events on Piton de la Fournaise Volcano  

NASA Astrophysics Data System (ADS)

Piton de la Fournaise (La Réunion island) is a very active basaltic volcano, with five eruptions between Nov 2009 and Dec 2010. Pre-eruptive seismic crises usually last for a few hours and mainly consist of a volcano-tectonic swarm. During the quiescent period between the volcano-tectonic swarm and the eruptive tremor, we identify another swarm of events with a very high frequency content. These events are shallow and are located close to the future eruption site. They seem associated with the opening of the path for the magma propagating laterally at shallow depth. As these events start to occur while the magma is still in a vertical propagation phase, this seismicity seems to be related with the generic response of the volcano to the stress perturbation and not directly induced by the magma pressure. This new observation brings new insights to short-term forecasting of the eruption location.

De Barros, Louis; Bean, Christopher J.; Zecevic, Megan; Brenguier, Florent; Peltier, Aline

2013-09-01

410

Deep magmatic structures of Hawaiian volcanoes, imaged by three-dimensional gravity models  

USGS Publications Warehouse

A simplified three-dimensional model for the island of Hawai'i, based on 3300 gravity measurements, provides new insights on magma pathways within the basaltic volcanoes. Gravity anomalies define dense cumulates and intrusions beneath the summits and known rift zones of every volcano. Linear gravity anomalies project southeast from Kohala and Mauna Kea summits and south from Huala??lai and Mauna Loa; these presumably express dense cores of previously unrecognized rift zones lacking surface expression. The gravity-modeled dense cores probably define tholeiitic shield-stage structures of the older volcanoes that are now veneered by late alkalic lavas. The three-dimensional gravity method is valuable for characterizing the magmatic systems of basaltic oceanic volcanoes and for defining structures related to landslide and seismic hazards.

Kauahikaua, J.; Hildenbrand, T.; Webring, M.

2000-01-01

411

Anfrageoptimierung in Volcano und Bjorn Scheuermann  

E-print Network

Anfrageoptimierung in Volcano und Cascades Bj¨orn Scheuermann Vortrag im Rahmen des Seminars Datenbanken, WS 03/04 Anfrageoptimierung in Volcano und Cascades ­ p.1/23 #12;Zielsetzung Entwicklung von ¨angig von konkretem Datenmodell Anfrageoptimierung in Volcano und Cascades ­ p.2/23 #12;Volcano

Mannheim, Universität

412

Geodetic observations and modeling of time-varying deformation at Taal Volcano, Philippines  

NASA Astrophysics Data System (ADS)

We investigate active crustal deformation patterns associated with magmatic activity at Taal Volcano, an active tholeiitic volcano located in southwestern Luzon, Philippines. We present comparisons of elastic and combined elastic-viscoelastic modeling results with deformation observed by continuous GPS measurements on and near the volcano. Continuous dual-frequency and single-frequency (L1) GPS data between 1998 and 2005 provide evidence for smoothly transitioning periods of inflation and deflation centered under the volcano. Within deformation phases that typically last 3-9 months (with rates exceeding 200 mm yr- 1), prominent inflationary phases were observed in February-November 2000 and June 2004-March 2005. The 2000 period of inflation was characterized by up to 145 mm yr- 1 surface extension and 220 mm yr- 1 of uplift of the center of Volcano Island relative to the northern caldera rim, while the 2005 inflation was characterized by as much as 116 mm yr- 1 horizontal extension of the volcanic edifice and 180 mm yr- 1 uplift. Inversions of observed surface deformation to determine the source location points to a relatively stable spherical source, situated under Volcano Island's central crater, at depths of ~ 5 km (based on the preferred Mogi model). Using this source geometry, we develop axisymmetric finite element models with annuli of concentric shells around the magma reservoir, embedded within a multi-layered elastic lithosphere. Using simply varying pressure histories as input, a variety of forward models are fit to the time history of continuously observed deformation for GPS stations located on Volcano Island. Though the inferred source geometry, volume and near-source rheological properties are non-unique, they represent more physically appropriate material properties than those assumed in simple elastic half-space models. The sources inferred using viscoelastic shell models suggest simpler pressure histories and reduced overall pressure changes, relative to equivalent elastic half-space models.

Galgana, Gerald A.; Newman, Andrew V.; Hamburger, Michael W.; Solidum, Renato U.

2014-02-01

413

Ferric Iron Precipitation in the Nagahama Bay, Satsuma Iwo-Jima Island, Kagoshima  

Microsoft Academic Search

Satsuma-Iwojima island is active volcanic island and 6 x 3 km in size, located 38km south of Kyushu island, Japan. The reddish brown water along the coast of the Iwo-dake volcano at the center of the island formed by neutralization through mixing of shallow hydrothermal fluid and seawater. The reddish brown water contains reddish ferrihydrite (Fe3+) that is derived from

T. Nagata; S. Kiyokawa; M. Ikehara; K. Oguri; S. Goto; T. Ito; K. E. Yamaguchi; T. Ueshiba

2010-01-01

414

Sulfur Volcanoes on Io?  

NASA Technical Reports Server (NTRS)

The unusual rheological properties of molten sulfur, in which viscosity decreases approximately four orders of magnitude as it cools from 170 to 120 C, may result in distinctive volcanic flow morphologies that allow sulfur flows and volcanoes to be identified on Io. Search of high resolution Voyager images reveals three features--Atar Patera, Daedalus Patera, and Kibero Patera--considered to be possible sulfur volcanoes based on their morphology. All three average 250 km in diameter and are distinguished by circular-to-oval central masses surrounded by irregular, widespread flows. Geometric relations indicate that the flows were emplaced after the central zone and appear to have emanated from their margins. The central zones are interpreted to be domes representing the high temperature stage of sulfur formed initially upon eruption. Rapid quenching formed a crust which preserved this phase of the emplacement. Upon cooling to 170 C, the sulfur reached a low viscosity runny stage and was released as the thin, widespread flows.

Greeley, R.; Fink, J.

1985-01-01

415

New Coastal Tsunami Gauges: Application at Augustine Volcano, Cook Inlet, Alaska  

Microsoft Academic Search

Recent eruptive activity at Augustine Volcano and its associated tsunami threat to lower Cook Inlet pointed out the need for a quickly deployable tsunami detector which could be installed on Augustine Island's coast. The detector's purpose would be to verify tsunami generation by direct observation of the wave at the source to support tsunami warning decisions along populated coastlines. To

M. Burgy; D. K. Bolton

2006-01-01

416

1996 volcanic activity in Alaska and Kamchatka: summary of events and response of the Alaska Volcano Observatory  

USGS Publications Warehouse

During 1996, the Alaska Volcano Observatory (AVO) responded to eruptive activity, anomalous seismicity, or suspected volcanic activity at 10 of the approximately 40 active volcanic centers in the state of Alaska. As part of a formal role in KVERT (the Kamchatkan Volcano Eruption Response Team), AVO staff also disseminated information about eruptions and other volcanic unrest at six volcanic centers on the Kamchatka Peninsula and in the Kurile Islands, Russia.

Neal, Christina A.; McGimsey, Robert G.

1997-01-01

417

Stratigraphy of the Hawai`i Scientific Drilling Project core (HSDP2): Anatomy of a Hawaiian shield volcano  

Microsoft Academic Search

The Hawai`i Scientific Drilling Project (HSDP2) successfully drilled ~3.1 km into the island of Hawai`i. Drilling started on Mauna Loa volcano, drilling 247 m of subaerial lavas before encountering 832 m of subaerial Mauna Kea lavas, followed by 2019 m of submarine Mauna Kea volcanic and sedimentary units. The 2.85 km stratigraphic record of Mauna Kea volcano spans back to

Michael O. Garcia; Eric H. Haskins; Edward M. Stolper; Michael Baker

2007-01-01

418

CALIPSO Borehole Instrumentation Project at Soufriere Hills Volcano, Montserrat, BWI: Data Acquisition, Telemetry, Integration, and Archival Systems  

Microsoft Academic Search

The CALIPSO Project (Caribbean Andesite Lava Island-volcano Precision Seismo-geodetic Observatory) has greatly enhanced the monitoring and scientific infrastructure at the Soufriere Hills Volcano, Montserrat with the recent installation of an integrated array of borehole and surface geophysical instrumentation at four sites. Each site was designed to be sufficiently hardened to withstand extreme meteorological events (e.g. hurricanes) and only require minimum

G. S. Mattioli; A. T. Linde; I. S. Sacks; P. E. Malin; E. Shalev; D. Elsworth; D. Hidayat; B. Voight; S. R. Young; P. N. Dunkley; R. Herd; G. Norton

2003-01-01

419

Volcano Hazards at Fuego and Acatenango, GuatemalaVolcano Hazards at Fuego and Acatenango, GuatemalaVolcano Hazards at Fuego and Acatenango, GuatemalaVolcano Hazards at Fuego and Acatenango, GuatemalaVolcano Hazards at Fuego and Acatenango, Guatemala 1111  

E-print Network

Volcano Hazards at Fuego and Acatenango, GuatemalaVolcano Hazards at Fuego and Acatenango, GuatemalaVolcano Hazards at Fuego and Acatenango, GuatemalaVolcano Hazards at Fuego and Acatenango, GuatemalaVolcano Hazards at Fuego and Acatenango, Guatemala 11111 Open-File Report 01­431Open-File Report 01

Rose, William I.

420

Mount Rainier active cascade volcano  

NASA Technical Reports Server (NTRS)

Mount Rainier is one of about two dozen active or recently active volcanoes in the Cascade Range, an arc of volcanoes in the northwestern United States and Canada. The volcano is located about 35 kilometers southeast of the Seattle-Tacoma metropolitan area, which has a population of more than 2.5 million. This metropolitan area is the high technology industrial center of the Pacific Northwest and one of the commercial aircraft manufacturing centers of the United States. The rivers draining the volcano empty into Puget Sound, which has two major shipping ports, and into the Columbia River, a major shipping lane and home to approximately a million people in southwestern Washington and northwestern Oregon. Mount Rainier is an active volcano. It last erupted approximately 150 years ago, and numerous large floods and debris flows have been generated on its slopes during this century. More than 100,000 people live on the extensive mudflow deposits that have filled the rivers and valleys draining the volcano during the past 10,000 years. A major volcanic eruption or debris flow could kill thousands of residents and cripple the economy of the Pacific Northwest. Despite the potential for such danger, Mount Rainier has received little study. Most of the geologic work on Mount Rainier was done more than two decades ago. Fundamental topics such as the development, history, and stability of the volcano are poorly understood.

1994-01-01