NissirosV1, PascalFrancis, Corpus, bibRecord, 000029

Recent activity of Nisyros volcano (Greece) inferred from structural, geochemical and seismological data

Identifieur interne : 000029 ( PascalFrancis/Corpus ); précédent : 000028; suivant : 000030

Recent activity of Nisyros volcano (Greece) inferred from structural, geochemical and seismological data

Auteurs : Stefano Caliro ; G. Chiodini ; D. Galluzzo ; D. Granieri ; M. La Rocca ; Gilberto Saccorotti ; G. Ventura

Source :

Bulletin of volcanology [ 0258-8900 ] ; 2005.

RBID : Pascal:05-0205976

Descripteurs français

Pascal (Inist)
- Grèce, Mer Egée, Volcan, Levé, Caldeira, Plaine, Faille, Ligne directionnelle, Filon, Cratère, Tectonique, Anomalie, Sol, Contrôle structural, Dégazage, Energie, Dôme, Eruption, Instrumentation, Séisme, Profondeur, Onde plane, Instabilité, Réservoir, Indicateur géochimique, Phénomène précurseur, Sismicité.

English descriptors

KwdEn :
- Aegean Sea, Greece, anomalies, calderas, craters, degassing, depth, domes, earthquakes, energy, eruptions, faults, geochemical indicators, instability, instruments, plains, plane waves, precursors, reservoirs, seismicity, soils, strike, structural controls, surveys, tectonics, veins, volcanoes.

Abstract

This study summarizes the results of structural, geochemical and seismological surveys carried out at Nisyros volcano (Aegean Sea, Greece) during 1999-2001. Field mapping and mesostructural measurements at the summit caldera (Lakki plain) indicate that faults follow two main strikes: NE-SW and N-S. The N-S striking fault depicts extensional features accommodating the left-lateral component of motion of the NE-SW- striking main faults. The NE-SW preferred strike of the Lakki faults and of the mineral-filled veins as well as the distribution and NE-SW elongation of the hydrothermal craters indicate that tectonics plays a major role in controlling the fluid pathway in the Nisyros caldera. The same NE-SW trend is depicted by CO₂ anomalies revealed through detailed soil CO₂ flux surveys, thus indicating a structural control on the pattern of the hydrothermal degassing. Degassing processes account for a thermal energy release of about 43 MW, most of which occurs at Lofos dome, an area that was affected by hydrothermal eruptions in historical times. The seismic study was conducted in June 2001, using a deployment specifically aimed at detecting signals of magmatic-hydrothermal origin. Our instruments recorded local and regional earthquakes, a few local long-period events (LP), and bursts of monochromatic tremor. Local earthquake activity is concentrated beneath the caldera, at depths generally shallower than 6 km. Plane-wave decomposition of tremor signal indicates a shallow (<200 m) source located in the eastern part of the caldera. Conversely, LP events depict a source located beneath the central part of the caldera, in the area of Lofos dome, at depths in the 1-2-km range. In agreement with geochemical and structural measurements, these data suggest that both the deeper and shallower part of the hydrothermal system are subjected to instability in the fluid flow regimes, probably consequent to transient pressurization of the reservoir. These instabilities may be related to input of hot fluids from the deeper magmatic system, as suggested by the variations in geochemical parameters observed after the 1997-1999 unrest episode. The significance of seismological and geochemical indicators as precursors of hydrothermal explosive activity at Nisyros is discussed.

Notice en format standard (ISO 2709)

Pour connaître la documentation sur le format Inist Standard.

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Format Inist (serveur)

NO :	PASCAL 05-0205976 INIST
ET :	Recent activity of Nisyros volcano (Greece) inferred from structural, geochemical and seismological data
AU :	CALIRO (Stefano); CHIODINI (G.); GALLUZZO (D.); GRANIERI (D.); LA ROCCA (M.); SACCOROTTI (Gilberto); VENTURA (G.)
AF :	Osservatorio Vesuviano, Istituto Nazionale di Geofisica e Vulcanologia, Via Diocleziano 328/80124 Napoli/Italie (1 aut., 2 aut., 3 aut., 4 aut., 5 aut., 6 aut., 7 aut.)
DT :	Publication en série; Niveau analytique
SO :	Bulletin of volcanology; ISSN 0258-8900; Coden BUVOEW; Allemagne; Da. 2005; Vol. 67; No. 4; Pp. 358-369; Bibl. 41 ref.
LA :	Anglais
EA :	This study summarizes the results of structural, geochemical and seismological surveys carried out at Nisyros volcano (Aegean Sea, Greece) during 1999-2001. Field mapping and mesostructural measurements at the summit caldera (Lakki plain) indicate that faults follow two main strikes: NE-SW and N-S. The N-S striking fault depicts extensional features accommodating the left-lateral component of motion of the NE-SW- striking main faults. The NE-SW preferred strike of the Lakki faults and of the mineral-filled veins as well as the distribution and NE-SW elongation of the hydrothermal craters indicate that tectonics plays a major role in controlling the fluid pathway in the Nisyros caldera. The same NE-SW trend is depicted by CO₂ anomalies revealed through detailed soil CO₂ flux surveys, thus indicating a structural control on the pattern of the hydrothermal degassing. Degassing processes account for a thermal energy release of about 43 MW, most of which occurs at Lofos dome, an area that was affected by hydrothermal eruptions in historical times. The seismic study was conducted in June 2001, using a deployment specifically aimed at detecting signals of magmatic-hydrothermal origin. Our instruments recorded local and regional earthquakes, a few local long-period events (LP), and bursts of monochromatic tremor. Local earthquake activity is concentrated beneath the caldera, at depths generally shallower than 6 km. Plane-wave decomposition of tremor signal indicates a shallow (<200 m) source located in the eastern part of the caldera. Conversely, LP events depict a source located beneath the central part of the caldera, in the area of Lofos dome, at depths in the 1-2-km range. In agreement with geochemical and structural measurements, these data suggest that both the deeper and shallower part of the hydrothermal system are subjected to instability in the fluid flow regimes, probably consequent to transient pressurization of the reservoir. These instabilities may be related to input of hot fluids from the deeper magmatic system, as suggested by the variations in geochemical parameters observed after the 1997-1999 unrest episode. The significance of seismological and geochemical indicators as precursors of hydrothermal explosive activity at Nisyros is discussed.
CC :	222A01; 226B02; 001E01F01; 001E01O02
FD :	Grèce; Mer Egée; Volcan; Levé; Caldeira; Plaine; Faille; Ligne directionnelle; Filon; Cratère; Tectonique; Anomalie; Sol; Contrôle structural; Dégazage; Energie; Dôme; Eruption; Instrumentation; Séisme; Profondeur; Onde plane; Instabilité; Réservoir; Indicateur géochimique; Phénomène précurseur; Sismicité
FG :	Europe Sud; Europe; Mer Méditerranée Est; Mer Méditerranée
ED :	Greece; Aegean Sea; volcanoes; surveys; calderas; plains; faults; strike; veins; craters; tectonics; anomalies; soils; structural controls; degassing; energy; domes; eruptions; instruments; earthquakes; depth; plane waves; instability; reservoirs; geochemical indicators; precursors; seismicity
EG :	Southern Europe; Europe; East Mediterranean; Mediterranean Sea
SD :	Grecia; Mar Egeo; Volcán; Caldera; Llano; Quebrado; Filón; Cráter; Tectónico; Anomalía; Suelo; Energía; Domo; Erupción; Instrumentación; Sismo; Profundidad; Indicador geoquímico; Fenómeno precursor; Sismicidad
LO :	INIST-2715.354000125677570070
ID :	05-0205976

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Le document en format XML

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<sZ>6 aut.</sZ>
<sZ>7 aut.</sZ>
</inist:fA14>
</affiliation>
</author>
<author><name sortKey="Granieri, D" sort="Granieri, D" uniqKey="Granieri D" first="D." last="Granieri">D. Granieri</name>
<affiliation><inist:fA14 i1="01"><s1>Osservatorio Vesuviano, Istituto Nazionale di Geofisica e Vulcanologia, Via Diocleziano 328</s1>
<s2>80124 Napoli</s2>
<s3>ITA</s3>
<sZ>1 aut.</sZ>
<sZ>2 aut.</sZ>
<sZ>3 aut.</sZ>
<sZ>4 aut.</sZ>
<sZ>5 aut.</sZ>
<sZ>6 aut.</sZ>
<sZ>7 aut.</sZ>
</inist:fA14>
</affiliation>
</author>
<author><name sortKey="La Rocca, M" sort="La Rocca, M" uniqKey="La Rocca M" first="M." last="La Rocca">M. La Rocca</name>
<affiliation><inist:fA14 i1="01"><s1>Osservatorio Vesuviano, Istituto Nazionale di Geofisica e Vulcanologia, Via Diocleziano 328</s1>
<s2>80124 Napoli</s2>
<s3>ITA</s3>
<sZ>1 aut.</sZ>
<sZ>2 aut.</sZ>
<sZ>3 aut.</sZ>
<sZ>4 aut.</sZ>
<sZ>5 aut.</sZ>
<sZ>6 aut.</sZ>
<sZ>7 aut.</sZ>
</inist:fA14>
</affiliation>
</author>
<author><name sortKey="Saccorotti, Gilberto" sort="Saccorotti, Gilberto" uniqKey="Saccorotti G" first="Gilberto" last="Saccorotti">Gilberto Saccorotti</name>
<affiliation><inist:fA14 i1="01"><s1>Osservatorio Vesuviano, Istituto Nazionale di Geofisica e Vulcanologia, Via Diocleziano 328</s1>
<s2>80124 Napoli</s2>
<s3>ITA</s3>
<sZ>1 aut.</sZ>
<sZ>2 aut.</sZ>
<sZ>3 aut.</sZ>
<sZ>4 aut.</sZ>
<sZ>5 aut.</sZ>
<sZ>6 aut.</sZ>
<sZ>7 aut.</sZ>
</inist:fA14>
</affiliation>
</author>
<author><name sortKey="Ventura, G" sort="Ventura, G" uniqKey="Ventura G" first="G." last="Ventura">G. Ventura</name>
<affiliation><inist:fA14 i1="01"><s1>Osservatorio Vesuviano, Istituto Nazionale di Geofisica e Vulcanologia, Via Diocleziano 328</s1>
<s2>80124 Napoli</s2>
<s3>ITA</s3>
<sZ>1 aut.</sZ>
<sZ>2 aut.</sZ>
<sZ>3 aut.</sZ>
<sZ>4 aut.</sZ>
<sZ>5 aut.</sZ>
<sZ>6 aut.</sZ>
<sZ>7 aut.</sZ>
</inist:fA14>
</affiliation>
</author>
</analytic>
<series><title level="j" type="main">Bulletin of volcanology</title>
<title level="j" type="abbreviated">Bull. volcanol.</title>
<idno type="ISSN">0258-8900</idno>
<imprint><date when="2005">2005</date>
</imprint>
</series>
</biblStruct>
</sourceDesc>
<seriesStmt><title level="j" type="main">Bulletin of volcanology</title>
<title level="j" type="abbreviated">Bull. volcanol.</title>
<idno type="ISSN">0258-8900</idno>
</seriesStmt>
</fileDesc>
<profileDesc><textClass><keywords scheme="KwdEn" xml:lang="en"><term>Aegean Sea</term>
<term>Greece</term>
<term>anomalies</term>
<term>calderas</term>
<term>craters</term>
<term>degassing</term>
<term>depth</term>
<term>domes</term>
<term>earthquakes</term>
<term>energy</term>
<term>eruptions</term>
<term>faults</term>
<term>geochemical indicators</term>
<term>instability</term>
<term>instruments</term>
<term>plains</term>
<term>plane waves</term>
<term>precursors</term>
<term>reservoirs</term>
<term>seismicity</term>
<term>soils</term>
<term>strike</term>
<term>structural controls</term>
<term>surveys</term>
<term>tectonics</term>
<term>veins</term>
<term>volcanoes</term>
</keywords>
<keywords scheme="Pascal" xml:lang="fr"><term>Grèce</term>
<term>Mer Egée</term>
<term>Volcan</term>
<term>Levé</term>
<term>Caldeira</term>
<term>Plaine</term>
<term>Faille</term>
<term>Ligne directionnelle</term>
<term>Filon</term>
<term>Cratère</term>
<term>Tectonique</term>
<term>Anomalie</term>
<term>Sol</term>
<term>Contrôle structural</term>
<term>Dégazage</term>
<term>Energie</term>
<term>Dôme</term>
<term>Eruption</term>
<term>Instrumentation</term>
<term>Séisme</term>
<term>Profondeur</term>
<term>Onde plane</term>
<term>Instabilité</term>
<term>Réservoir</term>
<term>Indicateur géochimique</term>
<term>Phénomène précurseur</term>
<term>Sismicité</term>
</keywords>
</textClass>
</profileDesc>
</teiHeader>
<front><div type="abstract" xml:lang="en">This study summarizes the results of structural, geochemical and seismological surveys carried out at Nisyros volcano (Aegean Sea, Greece) during 1999-2001. Field mapping and mesostructural measurements at the summit caldera (Lakki plain) indicate that faults follow two main strikes: NE-SW and N-S. The N-S striking fault depicts extensional features accommodating the left-lateral component of motion of the NE-SW- striking main faults. The NE-SW preferred strike of the Lakki faults and of the mineral-filled veins as well as the distribution and NE-SW elongation of the hydrothermal craters indicate that tectonics plays a major role in controlling the fluid pathway in the Nisyros caldera. The same NE-SW trend is depicted by CO<sub>2</sub>
 anomalies revealed through detailed soil CO<sub>2</sub>
 flux surveys, thus indicating a structural control on the pattern of the hydrothermal degassing. Degassing processes account for a thermal energy release of about 43 MW, most of which occurs at Lofos dome, an area that was affected by hydrothermal eruptions in historical times. The seismic study was conducted in June 2001, using a deployment specifically aimed at detecting signals of magmatic-hydrothermal origin. Our instruments recorded local and regional earthquakes, a few local long-period events (LP), and bursts of monochromatic tremor. Local earthquake activity is concentrated beneath the caldera, at depths generally shallower than 6 km. Plane-wave decomposition of tremor signal indicates a shallow (<200 m) source located in the eastern part of the caldera. Conversely, LP events depict a source located beneath the central part of the caldera, in the area of Lofos dome, at depths in the 1-2-km range. In agreement with geochemical and structural measurements, these data suggest that both the deeper and shallower part of the hydrothermal system are subjected to instability in the fluid flow regimes, probably consequent to transient pressurization of the reservoir. These instabilities may be related to input of hot fluids from the deeper magmatic system, as suggested by the variations in geochemical parameters observed after the 1997-1999 unrest episode. The significance of seismological and geochemical indicators as precursors of hydrothermal explosive activity at Nisyros is discussed.</div>
</front>
</TEI>
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<fA03 i2="1"><s0>Bull. volcanol.</s0>
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<fA05><s2>67</s2>
</fA05>
<fA06><s2>4</s2>
</fA06>
<fA08 i1="01" i2="1" l="ENG"><s1>Recent activity of Nisyros volcano (Greece) inferred from structural, geochemical and seismological data</s1>
</fA08>
<fA11 i1="01" i2="1"><s1>CALIRO (Stefano)</s1>
</fA11>
<fA11 i1="02" i2="1"><s1>CHIODINI (G.)</s1>
</fA11>
<fA11 i1="03" i2="1"><s1>GALLUZZO (D.)</s1>
</fA11>
<fA11 i1="04" i2="1"><s1>GRANIERI (D.)</s1>
</fA11>
<fA11 i1="05" i2="1"><s1>LA ROCCA (M.)</s1>
</fA11>
<fA11 i1="06" i2="1"><s1>SACCOROTTI (Gilberto)</s1>
</fA11>
<fA11 i1="07" i2="1"><s1>VENTURA (G.)</s1>
</fA11>
<fA14 i1="01"><s1>Osservatorio Vesuviano, Istituto Nazionale di Geofisica e Vulcanologia, Via Diocleziano 328</s1>
<s2>80124 Napoli</s2>
<s3>ITA</s3>
<sZ>1 aut.</sZ>
<sZ>2 aut.</sZ>
<sZ>3 aut.</sZ>
<sZ>4 aut.</sZ>
<sZ>5 aut.</sZ>
<sZ>6 aut.</sZ>
<sZ>7 aut.</sZ>
</fA14>
<fA20><s1>358-369</s1>
</fA20>
<fA21><s1>2005</s1>
</fA21>
<fA23 i1="01"><s0>ENG</s0>
</fA23>
<fA43 i1="01"><s1>INIST</s1>
<s2>2715</s2>
<s5>354000125677570070</s5>
</fA43>
<fA44><s0>0000</s0>
<s1>© 2005 INIST-CNRS. All rights reserved.</s1>
</fA44>
<fA45><s0>41 ref.</s0>
</fA45>
<fA47 i1="01" i2="1"><s0>05-0205976</s0>
</fA47>
<fA60><s1>P</s1>
</fA60>
<fA61><s0>A</s0>
</fA61>
<fA64 i1="01" i2="1"><s0>Bulletin of volcanology</s0>
</fA64>
<fA66 i1="01"><s0>DEU</s0>
</fA66>
<fC01 i1="01" l="ENG"><s0>This study summarizes the results of structural, geochemical and seismological surveys carried out at Nisyros volcano (Aegean Sea, Greece) during 1999-2001. Field mapping and mesostructural measurements at the summit caldera (Lakki plain) indicate that faults follow two main strikes: NE-SW and N-S. The N-S striking fault depicts extensional features accommodating the left-lateral component of motion of the NE-SW- striking main faults. The NE-SW preferred strike of the Lakki faults and of the mineral-filled veins as well as the distribution and NE-SW elongation of the hydrothermal craters indicate that tectonics plays a major role in controlling the fluid pathway in the Nisyros caldera. The same NE-SW trend is depicted by CO<sub>2</sub>
 anomalies revealed through detailed soil CO<sub>2</sub>
 flux surveys, thus indicating a structural control on the pattern of the hydrothermal degassing. Degassing processes account for a thermal energy release of about 43 MW, most of which occurs at Lofos dome, an area that was affected by hydrothermal eruptions in historical times. The seismic study was conducted in June 2001, using a deployment specifically aimed at detecting signals of magmatic-hydrothermal origin. Our instruments recorded local and regional earthquakes, a few local long-period events (LP), and bursts of monochromatic tremor. Local earthquake activity is concentrated beneath the caldera, at depths generally shallower than 6 km. Plane-wave decomposition of tremor signal indicates a shallow (<200 m) source located in the eastern part of the caldera. Conversely, LP events depict a source located beneath the central part of the caldera, in the area of Lofos dome, at depths in the 1-2-km range. In agreement with geochemical and structural measurements, these data suggest that both the deeper and shallower part of the hydrothermal system are subjected to instability in the fluid flow regimes, probably consequent to transient pressurization of the reservoir. These instabilities may be related to input of hot fluids from the deeper magmatic system, as suggested by the variations in geochemical parameters observed after the 1997-1999 unrest episode. The significance of seismological and geochemical indicators as precursors of hydrothermal explosive activity at Nisyros is discussed.</s0>
</fC01>
<fC02 i1="01" i2="2"><s0>222A01</s0>
</fC02>
<fC02 i1="02" i2="2"><s0>226B02</s0>
</fC02>
<fC02 i1="03" i2="2"><s0>001E01F01</s0>
</fC02>
<fC02 i1="04" i2="2"><s0>001E01O02</s0>
</fC02>
<fC03 i1="01" i2="2" l="FRE"><s0>Grèce</s0>
<s2>NG</s2>
<s5>01</s5>
</fC03>
<fC03 i1="01" i2="2" l="ENG"><s0>Greece</s0>
<s2>NG</s2>
<s5>01</s5>
</fC03>
<fC03 i1="01" i2="2" l="SPA"><s0>Grecia</s0>
<s2>NG</s2>
<s5>01</s5>
</fC03>
<fC03 i1="02" i2="2" l="FRE"><s0>Mer Egée</s0>
<s2>NG</s2>
<s5>02</s5>
</fC03>
<fC03 i1="02" i2="2" l="ENG"><s0>Aegean Sea</s0>
<s2>NG</s2>
<s5>02</s5>
</fC03>
<fC03 i1="02" i2="2" l="SPA"><s0>Mar Egeo</s0>
<s2>NG</s2>
<s5>02</s5>
</fC03>
<fC03 i1="03" i2="2" l="FRE"><s0>Volcan</s0>
<s5>06</s5>
</fC03>
<fC03 i1="03" i2="2" l="ENG"><s0>volcanoes</s0>
<s5>06</s5>
</fC03>
<fC03 i1="03" i2="2" l="SPA"><s0>Volcán</s0>
<s5>06</s5>
</fC03>
<fC03 i1="04" i2="2" l="FRE"><s0>Levé</s0>
<s5>07</s5>
</fC03>
<fC03 i1="04" i2="2" l="ENG"><s0>surveys</s0>
<s5>07</s5>
</fC03>
<fC03 i1="05" i2="2" l="FRE"><s0>Caldeira</s0>
<s5>08</s5>
</fC03>
<fC03 i1="05" i2="2" l="ENG"><s0>calderas</s0>
<s5>08</s5>
</fC03>
<fC03 i1="05" i2="2" l="SPA"><s0>Caldera</s0>
<s5>08</s5>
</fC03>
<fC03 i1="06" i2="2" l="FRE"><s0>Plaine</s0>
<s5>09</s5>
</fC03>
<fC03 i1="06" i2="2" l="ENG"><s0>plains</s0>
<s5>09</s5>
</fC03>
<fC03 i1="06" i2="2" l="SPA"><s0>Llano</s0>
<s5>09</s5>
</fC03>
<fC03 i1="07" i2="2" l="FRE"><s0>Faille</s0>
<s5>10</s5>
</fC03>
<fC03 i1="07" i2="2" l="ENG"><s0>faults</s0>
<s5>10</s5>
</fC03>
<fC03 i1="07" i2="2" l="SPA"><s0>Quebrado</s0>
<s5>10</s5>
</fC03>
<fC03 i1="08" i2="2" l="FRE"><s0>Ligne directionnelle</s0>
<s5>11</s5>
</fC03>
<fC03 i1="08" i2="2" l="ENG"><s0>strike</s0>
<s5>11</s5>
</fC03>
<fC03 i1="09" i2="2" l="FRE"><s0>Filon</s0>
<s5>12</s5>
</fC03>
<fC03 i1="09" i2="2" l="ENG"><s0>veins</s0>
<s5>12</s5>
</fC03>
<fC03 i1="09" i2="2" l="SPA"><s0>Filón</s0>
<s5>12</s5>
</fC03>
<fC03 i1="10" i2="2" l="FRE"><s0>Cratère</s0>
<s5>13</s5>
</fC03>
<fC03 i1="10" i2="2" l="ENG"><s0>craters</s0>
<s5>13</s5>
</fC03>
<fC03 i1="10" i2="2" l="SPA"><s0>Cráter</s0>
<s5>13</s5>
</fC03>
<fC03 i1="11" i2="2" l="FRE"><s0>Tectonique</s0>
<s5>14</s5>
</fC03>
<fC03 i1="11" i2="2" l="ENG"><s0>tectonics</s0>
<s5>14</s5>
</fC03>
<fC03 i1="11" i2="2" l="SPA"><s0>Tectónico</s0>
<s5>14</s5>
</fC03>
<fC03 i1="12" i2="2" l="FRE"><s0>Anomalie</s0>
<s5>15</s5>
</fC03>
<fC03 i1="12" i2="2" l="ENG"><s0>anomalies</s0>
<s5>15</s5>
</fC03>
<fC03 i1="12" i2="2" l="SPA"><s0>Anomalía</s0>
<s5>15</s5>
</fC03>
<fC03 i1="13" i2="2" l="FRE"><s0>Sol</s0>
<s5>16</s5>
</fC03>
<fC03 i1="13" i2="2" l="ENG"><s0>soils</s0>
<s5>16</s5>
</fC03>
<fC03 i1="13" i2="2" l="SPA"><s0>Suelo</s0>
<s5>16</s5>
</fC03>
<fC03 i1="14" i2="2" l="FRE"><s0>Contrôle structural</s0>
<s5>17</s5>
</fC03>
<fC03 i1="14" i2="2" l="ENG"><s0>structural controls</s0>
<s5>17</s5>
</fC03>
<fC03 i1="15" i2="2" l="FRE"><s0>Dégazage</s0>
<s5>18</s5>
</fC03>
<fC03 i1="15" i2="2" l="ENG"><s0>degassing</s0>
<s5>18</s5>
</fC03>
<fC03 i1="16" i2="2" l="FRE"><s0>Energie</s0>
<s5>19</s5>
</fC03>
<fC03 i1="16" i2="2" l="ENG"><s0>energy</s0>
<s5>19</s5>
</fC03>
<fC03 i1="16" i2="2" l="SPA"><s0>Energía</s0>
<s5>19</s5>
</fC03>
<fC03 i1="17" i2="2" l="FRE"><s0>Dôme</s0>
<s5>20</s5>
</fC03>
<fC03 i1="17" i2="2" l="ENG"><s0>domes</s0>
<s5>20</s5>
</fC03>
<fC03 i1="17" i2="2" l="SPA"><s0>Domo</s0>
<s5>20</s5>
</fC03>
<fC03 i1="18" i2="2" l="FRE"><s0>Eruption</s0>
<s5>21</s5>
</fC03>
<fC03 i1="18" i2="2" l="ENG"><s0>eruptions</s0>
<s5>21</s5>
</fC03>
<fC03 i1="18" i2="2" l="SPA"><s0>Erupción</s0>
<s5>21</s5>
</fC03>
<fC03 i1="19" i2="2" l="FRE"><s0>Instrumentation</s0>
<s5>22</s5>
</fC03>
<fC03 i1="19" i2="2" l="ENG"><s0>instruments</s0>
<s5>22</s5>
</fC03>
<fC03 i1="19" i2="2" l="SPA"><s0>Instrumentación</s0>
<s5>22</s5>
</fC03>
<fC03 i1="20" i2="2" l="FRE"><s0>Séisme</s0>
<s5>23</s5>
</fC03>
<fC03 i1="20" i2="2" l="ENG"><s0>earthquakes</s0>
<s5>23</s5>
</fC03>
<fC03 i1="20" i2="2" l="SPA"><s0>Sismo</s0>
<s5>23</s5>
</fC03>
<fC03 i1="21" i2="2" l="FRE"><s0>Profondeur</s0>
<s5>24</s5>
</fC03>
<fC03 i1="21" i2="2" l="ENG"><s0>depth</s0>
<s5>24</s5>
</fC03>
<fC03 i1="21" i2="2" l="SPA"><s0>Profundidad</s0>
<s5>24</s5>
</fC03>
<fC03 i1="22" i2="2" l="FRE"><s0>Onde plane</s0>
<s5>25</s5>
</fC03>
<fC03 i1="22" i2="2" l="ENG"><s0>plane waves</s0>
<s5>25</s5>
</fC03>
<fC03 i1="23" i2="2" l="FRE"><s0>Instabilité</s0>
<s5>61</s5>
</fC03>
<fC03 i1="23" i2="2" l="ENG"><s0>instability</s0>
<s5>61</s5>
</fC03>
<fC03 i1="24" i2="2" l="FRE"><s0>Réservoir</s0>
<s5>62</s5>
</fC03>
<fC03 i1="24" i2="2" l="ENG"><s0>reservoirs</s0>
<s5>62</s5>
</fC03>
<fC03 i1="25" i2="2" l="FRE"><s0>Indicateur géochimique</s0>
<s5>63</s5>
</fC03>
<fC03 i1="25" i2="2" l="ENG"><s0>geochemical indicators</s0>
<s5>63</s5>
</fC03>
<fC03 i1="25" i2="2" l="SPA"><s0>Indicador geoquímico</s0>
<s5>63</s5>
</fC03>
<fC03 i1="26" i2="2" l="FRE"><s0>Phénomène précurseur</s0>
<s5>64</s5>
</fC03>
<fC03 i1="26" i2="2" l="ENG"><s0>precursors</s0>
<s5>64</s5>
</fC03>
<fC03 i1="26" i2="2" l="SPA"><s0>Fenómeno precursor</s0>
<s5>64</s5>
</fC03>
<fC03 i1="27" i2="2" l="FRE"><s0>Sismicité</s0>
<s5>65</s5>
</fC03>
<fC03 i1="27" i2="2" l="ENG"><s0>seismicity</s0>
<s5>65</s5>
</fC03>
<fC03 i1="27" i2="2" l="SPA"><s0>Sismicidad</s0>
<s5>65</s5>
</fC03>
<fC07 i1="01" i2="2" l="FRE"><s0>Europe Sud</s0>
<s2>NG</s2>
</fC07>
<fC07 i1="01" i2="2" l="ENG"><s0>Southern Europe</s0>
<s2>NG</s2>
</fC07>
<fC07 i1="01" i2="2" l="SPA"><s0>Europa Sur</s0>
<s2>NG</s2>
</fC07>
<fC07 i1="02" i2="2" l="FRE"><s0>Europe</s0>
</fC07>
<fC07 i1="02" i2="2" l="ENG"><s0>Europe</s0>
</fC07>
<fC07 i1="02" i2="2" l="SPA"><s0>Europa</s0>
</fC07>
<fC07 i1="03" i2="2" l="FRE"><s0>Mer Méditerranée Est</s0>
<s2>NG</s2>
</fC07>
<fC07 i1="03" i2="2" l="ENG"><s0>East Mediterranean</s0>
<s2>NG</s2>
</fC07>
<fC07 i1="03" i2="2" l="SPA"><s0>Mar Mediterraneo Este</s0>
<s2>NG</s2>
</fC07>
<fC07 i1="04" i2="2" l="FRE"><s0>Mer Méditerranée</s0>
</fC07>
<fC07 i1="04" i2="2" l="ENG"><s0>Mediterranean Sea</s0>
</fC07>
<fC07 i1="04" i2="2" l="SPA"><s0>Mar Mediterráneo</s0>
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<server><NO>PASCAL 05-0205976 INIST</NO>
<ET>Recent activity of Nisyros volcano (Greece) inferred from structural, geochemical and seismological data</ET>
<AU>CALIRO (Stefano); CHIODINI (G.); GALLUZZO (D.); GRANIERI (D.); LA ROCCA (M.); SACCOROTTI (Gilberto); VENTURA (G.)</AU>
<AF>Osservatorio Vesuviano, Istituto Nazionale di Geofisica e Vulcanologia, Via Diocleziano 328/80124 Napoli/Italie (1 aut., 2 aut., 3 aut., 4 aut., 5 aut., 6 aut., 7 aut.)</AF>
<DT>Publication en série; Niveau analytique</DT>
<SO>Bulletin of volcanology; ISSN 0258-8900; Coden BUVOEW; Allemagne; Da. 2005; Vol. 67; No. 4; Pp. 358-369; Bibl. 41 ref.</SO>
<LA>Anglais</LA>
<EA>This study summarizes the results of structural, geochemical and seismological surveys carried out at Nisyros volcano (Aegean Sea, Greece) during 1999-2001. Field mapping and mesostructural measurements at the summit caldera (Lakki plain) indicate that faults follow two main strikes: NE-SW and N-S. The N-S striking fault depicts extensional features accommodating the left-lateral component of motion of the NE-SW- striking main faults. The NE-SW preferred strike of the Lakki faults and of the mineral-filled veins as well as the distribution and NE-SW elongation of the hydrothermal craters indicate that tectonics plays a major role in controlling the fluid pathway in the Nisyros caldera. The same NE-SW trend is depicted by CO<sub>2</sub>
 anomalies revealed through detailed soil CO<sub>2</sub>
 flux surveys, thus indicating a structural control on the pattern of the hydrothermal degassing. Degassing processes account for a thermal energy release of about 43 MW, most of which occurs at Lofos dome, an area that was affected by hydrothermal eruptions in historical times. The seismic study was conducted in June 2001, using a deployment specifically aimed at detecting signals of magmatic-hydrothermal origin. Our instruments recorded local and regional earthquakes, a few local long-period events (LP), and bursts of monochromatic tremor. Local earthquake activity is concentrated beneath the caldera, at depths generally shallower than 6 km. Plane-wave decomposition of tremor signal indicates a shallow (<200 m) source located in the eastern part of the caldera. Conversely, LP events depict a source located beneath the central part of the caldera, in the area of Lofos dome, at depths in the 1-2-km range. In agreement with geochemical and structural measurements, these data suggest that both the deeper and shallower part of the hydrothermal system are subjected to instability in the fluid flow regimes, probably consequent to transient pressurization of the reservoir. These instabilities may be related to input of hot fluids from the deeper magmatic system, as suggested by the variations in geochemical parameters observed after the 1997-1999 unrest episode. The significance of seismological and geochemical indicators as precursors of hydrothermal explosive activity at Nisyros is discussed.</EA>
<CC>222A01; 226B02; 001E01F01; 001E01O02</CC>
<FD>Grèce; Mer Egée; Volcan; Levé; Caldeira; Plaine; Faille; Ligne directionnelle; Filon; Cratère; Tectonique; Anomalie; Sol; Contrôle structural; Dégazage; Energie; Dôme; Eruption; Instrumentation; Séisme; Profondeur; Onde plane; Instabilité; Réservoir; Indicateur géochimique; Phénomène précurseur; Sismicité</FD>
<FG>Europe Sud; Europe; Mer Méditerranée Est; Mer Méditerranée</FG>
<ED>Greece; Aegean Sea; volcanoes; surveys; calderas; plains; faults; strike; veins; craters; tectonics; anomalies; soils; structural controls; degassing; energy; domes; eruptions; instruments; earthquakes; depth; plane waves; instability; reservoirs; geochemical indicators; precursors; seismicity</ED>
<EG>Southern Europe; Europe; East Mediterranean; Mediterranean Sea</EG>
<SD>Grecia; Mar Egeo; Volcán; Caldera; Llano; Quebrado; Filón; Cráter; Tectónico; Anomalía; Suelo; Energía; Domo; Erupción; Instrumentación; Sismo; Profundidad; Indicador geoquímico; Fenómeno precursor; Sismicidad</SD>
<LO>INIST-2715.354000125677570070</LO>
<ID>05-0205976</ID>
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Recent activity of Nisyros volcano (Greece) inferred from structural, geochemical and seismological data

Recent activity of Nisyros volcano (Greece) inferred from structural, geochemical and seismological data

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