Volcanoes and Volcanic Rocks IILava FloodsFlood Basalts, Columbia RiverColumnar Jointing, Devil’s Postpile, CAColumnar JointingEmpty Lava TubePillow Basalts, IcelandComposite VolcanoPopocatépetl, Mexico, 1960Recent Global Volcanic ActivityIntroduction to Pyroclastic VolcanismVolatile Control on Eruption StylePressure Effects on Volatile-rich SystemsVolatiles and EruptionsDome Formation1993 Dome MSHcircum-Caribbean seismicityCaribbean bathymetryMontserrat Location Map1995 Tar River Valley1995 earthquakesDestroyed Hermitage CGPS Site, 1996Kinematic Flow ModelsRequired dataSlide 25Tar River Valley, Spring 1996Simulated Flow VelocitiesSHV Pyroclastic Deposits to 1998New Tar River DeltaPlymouth, Montserrat - Oct. 1997Sub-surface magmatic processesHermitage CGPS site, Jul. 1996General CGPS SchematicVulcanian Explosions, Oct. 1997GPS Data and Elastic ModelGPS Vertical Velocity FieldCALIPSO Borehole ObservatoryUnloading DOSECC Drill RigSHV Dome - Dec. 2002Drilling Operations & Core LoggingGrouting Strainmeter at Air StudiosTrants ConstructionTrants Instrument Crypt & GPS MonumentReftek DownloadsJuly 12th PF’sJuly 12 DataAir Studios on July 14thAsh in Olveston - July 13thVolcanoes and Volcanic Rocks IIVolcanoes and Volcanic Rocks IIPhoto credit: G. MattioliSubmarine Eruptions•Pillow BasaltsLava FloodsFlood Basalts, Columbia RiverColumnar Jointing, Devil’s Postpile, CAColumnar JointingEmpty Lava TubePillow Basalts, IcelandComposite VolcanoPopocatépetl, Mexico, 1960Recent Global Volcanic ActivityIntroduction to Pyroclastic Volcanism•Volcanic rocks and tectonics•Island arcs as sites for pyroclastic rocks•Pyroclastic rock generation modes•Effusive vs. explosive volcanism•Some characteristics of pyroclastic rocks•Soufriere Hills Volcano, MontserratFrom: Sparks, 1978Volatile Control on Eruption StylePressure Effects on Volatile-rich SystemsFrom: Best, 2003Volatiles and EruptionsFrom: Best, 2003Dome Formation1993 Dome MSHCaribbeanepicenters < 30 km depth from USGScircum-Caribbean seismicityModified from: Jansma et al., 2000BR: Beata Ridge; HE: Hess EscarpmentNPDB: North Panama Deformed Belt; SCDB: South Caribbean deformed beltCaribbean bathymetryMontserrat Location MapFrom: Mattioli et al., 1998Tar River Valley - Looking ENEOctober 1995English Crater4 Ka Sector Collapse1995 Tar River ValleyPhoto credit: G. WadgeVT Eqs ->Harmonic Tremor1995 earthquakesDestroyed Hermitage CGPS Site, 1996Photo credit: G. MattioliKinematic Flow Models•Theoretical background•Data required•Parameterization of the models•Results from Montserrat•ImplicationsRequired data•Accurate DEM’s - required adding a synthetic dome to generate current topopgraphy not on available maps•Previous direct measurements at other similar volcanoes: Mt. St. Helen’s and Mt. UnzenKinematic Flow ModelsFrom: Hooper & Mattioli, 2001Tar River Valley, Spring 1996Photo credit: G. MattioliBurnt Zone - Initial channelization of small PF’sSimulated Flow VelocitiesFrom: Hooper & Mattioli, 2001SHV Pyroclastic Deposits to 1998New Tar River DeltaPhoto credit: Steve O’Meara Volcano Watch InternationalJuly 12th 2003 eruptionFrom: http://www.bgs.ac.uk/news/montserrat.htmlPlymouth, Montserrat - Oct. 1997Photo credit: G. MattioliSub-surface magmatic processes•Campaign and continuous GPS geodesy done from 1995-2003•Several CGPS sites destroyed over the years; current network was 6 sites; WTYD site destroyed on July 12th, but will be replaced.•Data processed in absolute point positioning mode with final JPL orbits, clocks, and earth orientation parameters•CALIPSO Project recently added 4 additional sitesHermitage CGPS site, Jul. 1996Photo credit: G. MattioliGeneral CGPS Schematic<-Dome GrowthExplosions -><- SubsidenceNo Surface FluxInflation ->RenewedDomeGrowthSubsidenceAgain! ->Vulcanian Explosions, Oct. 1997~13 kmPhoto credits: G. MattioliData from: Mattioli et al., 2001; Sparks et al., 1998GPS Data and Elastic ModelFrom: Mattioli et al., 2002GPS Vertical Velocity FieldFrom: Mattioli et al., 1998; Mattioli et al., 2002CALIPSO Borehole Observatory•Sacks-Evertson single component dilatometer (10-9 strain)•Nearly broadband 3 component seismometer (~2 Hz to 1 kHz)•Pinnacle Systems short-baseline electronic tiltmeter•Ashtech µ-Z code-phase CGPS w/ choke ring antennaUnloading DOSECC Drill RigPhoto credits: G. MattioliPhoto of dome in Dec. 02 on a rare clear day. By July 2003 the dome had grown to >230 M m3 and had not collapsed significantly for 2 years!!SHV Dome - Dec. 2002Photo credit: G. MattioliDrilling Operations& Core LoggingPhoto credits: G. MattioliGrouting Strainmeter at Air StudiosPhoto credit: G. MattioliTrants ConstructionPhoto credit: G. MattioliTrants Instrument Crypt & GPS MonumentPhoto credit: G. MattioliReftek DownloadsPhoto credit: G. MattioliJuly 12th, 2003 - Dome collapse begins at 9 AM AST By sunset, pyroclastic flows are getting more energetic and now routinely reach the sea at the Tar River delta. NB white is steam while gray is co-ignimbrite ash cloud.July 12th PF’sPhoto credit: G. MattioliTrants Borehole Seismic and Strain Records for July 12thSub-plinian to Plinian event at ~11 PM ASTAlthough Trants site was impacted by ash during theculminating event of the July12th dome collapse, the CALIPSOBH instruments functionedthroughout the eruption.Seismometer 200 Hz (8:03 PM to 12:13AM AST)Strainmeter 50 Hz (8:42 PM to 12:42AM AST)July 12 DataPhoto credit: G. MattioliFirst visit to Air Studios on July 14th - 12.5 cm of ash and 6 cm mud in crypt; NB infrasound microphone under ash, but CALIPSO was still up!Air Studios on July 14thPhoto credits: G. MattioliThe morning after at Sea Dreams in Olveston12 cm of ash and 6.5 cmpumice fragments!Photo credits: G. MattioliAsh in Olveston - July