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Calderas of Nicaragua - Activity and Monitoring

Calderas of Nicaragua - Activity and Monitoring. Virginia Tenorio INETER, Dirección General de Geofísica Managua, Nicaragua. Foto: Open vent at Masaya volcano. Nicaraguan Volcanic Chain. Monitoring Systems. Visits to active craters in regular periods

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Calderas of Nicaragua - Activity and Monitoring

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  1. Calderas of Nicaragua - Activity and Monitoring Virginia TenorioINETER, Dirección General de GeofísicaManagua, Nicaragua Foto: Open vent at Masaya volcano

  2. NicaraguanVolcanicChain

  3. Monitoring Systems • Visits to active craters in regular periods • One seismic station near the active crater • and main volcanic centers (and not active) • Seismic Networks at most active volcanoes • Permanent MiniDOAS, mobile miniDOAS • GPS sites, regular campaigns

  4. Telica Volcano May, 2011 San Cristobal Volcano April, 2006

  5. Cosigüina Caldera Height:859 m Activity:1835 - Huge eruption from central crater, !!Little damage due tolow population densityType of Eruption: Plinian-PhreatomagmaticVEI:5 Hazard Index:14 Recent activity:Seismicity, 2002 Monitoring:Seismic broad band station

  6. Cosigüina Caldera – recent activity September 2002 - Strong seismic activity near Cosigüina volcano. First mayor activity known in 27 years of the existence of the Nicaraguan seismic Network.Also, in the historic records there appears Very little information on strong seismic activity like in septiember, 2002

  7. Cosigüina 2002 - Magnitude vs. time • Typical for volcano.-seismic activity (VT): • - The events ocurred in various pulses • The pulses liberated similar amounts of seismic energy • Ocurred many events with similar magnitude 3 <M < 4 • The maximum magnitude increased 2 times • The distribution of energy was unlike tectonic activity

  8. Conclusión According to the formula of R. White for intruded volume from seismic moment, the volume of magma would be roughly about 500,000 m3 This didn’t seem like nearly enough to reach the surface. We remained on alert for further seismic activity or any volcanic activity but none followed.

  9. MomotomboVolcano(remanent of Monte Galan Caldera) Height:1,100mActivity:Eruption in centralcrater Type of Eruption: StrombolianaVEI:2Hazard Index:11History:10 eruptions since 1524Actividad actual:Seismicity, Fumaroles T>700 C

  10. Hazard • Earthquakes • Landslides • Lahars • Ash fall • Lava flows • Catastrophic Explosions Momotombo Volcano Visittothecrater Frequent seismic swarms Example: Seismicity of June, 2000

  11. ApoyequeCaldera Height:420mType of Actividad: Eruption of central craterType of Eruption:PlinianHistory:Plinian 12, 6 , 2 thousand years agoRecent actividad:Seismicity Swarms • Volcano hazard • Ash fall (3 m in Managua) • Pyroclastic flows –> Managua!- Lahars, Earthquakes M=5.0, Jan 2001. Thermal springs

  12. Managua – Volcanic Hazard Apoyeque Caldera Managua (1 million) Cd. Sandino (80 000) Nejapa-Miraflores Lineament (Maars) Tiscapa volcano Masaya (100 000) Apoyo Caldera Masaya Caldera

  13. Apoyo Caldera Height:635mType of Activity:ExplosiveEruption Type: PlineanLast eruption: 22 y 17 thousandyears agoRecent activity:Frequent seismicswarmsDestructive earthquake M=5.2, July 2000. 0.5 m displacement vertical Thermal springs . High SO2, CO2. Peoples died

  14. Santiago CraterMasaya Caldera Height:635mType of ActivityViolent crisis due to degasificationType of Eruption: Hawaiian StrombolianaVEI:2Hazard Index:10History:Very Active since 1720Recent Activity:Lava LakeSO2 5000 t/day, sporadic explosions

  15. Volcanic hazard • Lava flows • Lahars Huella de Acuahualinca

  16. MasayaVolcano • Volcanic hazard • - Pyroclastic flows • Ash fall • Gas column • Sporadic explotion Explosion. April, 2001

  17. Volcanic hazard - Seismic events

  18. Destructive Earthquakes between Apoyo and Masaya calderas July, 2000: Two main events of magnitud 5.4 and 5.2 with one day time difference. One minute before, the Earthquake occurred

  19. Destructive Earthquakes between Apoyo and Masaya calderas July, 2000: Two main events of magnitud 5.4 and 5.2 with one day time difference. foreshock M=5.4

  20. M=5.2 M=5.4

  21. Conclusions • It appears that calderas are exceptionally stable volcanic structures, in the sense that they can accommodate a large amount of unrest, especially occasional intrusions, without producing eruptions. • It appears that they can accommodate significant purely tectonic activity as well, that does not affect the volcanic system in any visible way. • It also appears that adjacent calderas may be connected by tectonic structures and transfer stresses from one to the other without transfering any significant stress to the magma?

  22. Volcano Disaster Plans for Managua Rapid automaticinformation system for seismic events within 2 minutes Nicaraguan Civil Defense Monitoring and Operations Center Discussion on Emergency Plans for Managua Gen. Perezcassar and V. Tenorio

  23. GRACIAS

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