Multidisciplinary monitoring of Mt. Mayon, Luzon, Philippines Part 1 – Overview and Geochemical Monitoring F M Schwandner1, D Hidayat1, S Marcial1, C Newhall1, E Laguerta2, R Vaquilar2, A Baloloy2, R Valerio2
• Research collaboration: Earth Observatory of Singapore, Philippine Institute of Volcanology and Seismology (PHIVOLCS) since 2010• Objective: Develop a multi-disciplinary monitoring system around Mayon• geophysical & gas geochemical monitoring, and petrologic studies.
1. Mayon volcano: Background activityMayon is an openly-degassed basaltic-andesitic volcano, rises to 2,462m above Albay Gulfin the Philippines.Considered the most active volcano in the Philippines, Mayon produce small eruptionsevery few years with two large (VEI 4) historical eruptions in 1814 and 1897.The two recent eruptions in 2006 and 2009 were largely effusive, produced lava flow andpyroclastic flows.In the spectrum from openly-degassed to plugged volcanoes,Mayon is near the openly-degassing end, producing mostly small and frequent eruptions. b
1. Mayon volcano: Background activityRelatively short and modest seismic and gas precursors to recent eruptions of Mayon. SO2 flux in t/d SDH: emergent “tremor”, including rock falls Data courtesy of (PHIVOLCS). LF- and HF- VQ: low and high frequency volcanic earthquakes
1. Mayon volcano: Background activityIn the latest eruption, a small explosion on early Dec 11, 2009 was followed by spillingof incandescent blocks over the crater rim.Both the 2006 and 2009 eruptions started slowly with rock falls and increased SO2.Extrusion rate peaked within 1-2 weeks and died away within 3-6 weeks. Only minorexplosive activity occurred. SO2 flux in t/d SDH: emergent “tremor”, including rock falls LF- and HF- VQ: low and high frequency volcanic earthquakes Data courtesy of (PHIVOLCS).
1. Mayon volcano: Background activity Mayon volcano status is level-1 with low seismicity dominated mostly by local and regional tectonic earthquakes with continuous emission of SO2 from its crater.Reported volcanic earthquakes and seismically detected rock fall events per month (dark and lightgray bars, respectively, left axis) and SO2 flux (open triangles and dashed line) averaged per month(right axis) at Mayon from 1 January 2010 to July 2011.Background colors indicate the Alert Level corresponding to the scale to the right of the figure.Little if any data are available from March through December 2010, presumably due to low activityduring this interval. Data courtesy of (PHIVOLCS).
• Research collaboration:Mayon monitoring network design Earth Observatory of Singapore, Philippine Institute of Volcanology and Seismology (PHIVOLCS) since 2010 • Objective: Develop a multi-disciplinary monitoring system around Mayon • geophysical & gas geochemical monitoring, and petrologic studies.
Gas Geochemistry:flank CO2 as early unrest indicator
Gas Geochemistry:flank CO2 as early unrest indicator • Ground/flank gas network: – Low cost, low maintenance = networkable, (+ solar power, telemetry) – Chamber: US$45k/ea; high wear, strongly affected by wind & rain – Pipe: US$05k/ea; low-flow $1k only, minimum wear & noise Options: • Continuous (recirculation) mode, • Pump Test mode
Gas Geochemistry:flank CO2 as early unrest indicator: toward real-time flux fields End: Flux field variations with time Temporal population variation loadings Invert Start: Measure flux grid or mesh Measure time series, apply met corrections Spatial population variation loadings Refine operational parameters Extract population statistics: Place, cal, val time series sensors PDF (permeability distribution function)
Gas Geochemistry: flank CO2 as early unrest indicatorMultisensor gas stations design (6 Mayon, 2 Gede)• Prototype built, copies being built in Nov-Dec 2011, at Mayon since Nov 2011. Gas permeability / flux mapping with EOS• Include each: Vaisala met station, soil CO2 concentration students, PHIVOLCS colleagues. Mayon 7/2011. and derived CO2 flux, heat flux, soil moisture & soil temperature.• Telemetry pending repeaters finalization.• Supporting data acquired July 2011 (flux & permeability mapping campaigns). Multi-sensors box designed for volcano monitoring stations. Schwandner & Marcial 2011. Inset photo displays how wall installation will appear like, inside the shelters, in January 2011.
Gas Geochemistry:Conduit degassing monitoring (NOVAC SO2)NOVAC SO2 monitoring stations (2 Mayon)• April/May 2011 installed. First in Asia, of global network >50 sites.• Collaboration with NOVAC (Bo Galle, Sweden).• Telemetry pending repeaters completion.• PHIVOLCS scientists trained.• Data streams being finalized: node -> observatory -> NOVAC -> EOS & PHIVOLCS HQOne of two NOVAC stations at Mayon (Calbayog station) Installation in May 2011 Sample 180 degree scan in 5 degree slant column absorption measurement intervals. Highlighted is edge of plume just outside the scan range. Lightning rod Scanner optics Control box including spectrometer, batteries, solar charge controllers.
Hydrology / Geochemistry: Strain and flank degassing monitoringWells multi-sensors (2 at Mayon)• Sensors: depth (strain), pH, conductivity, salinity, chloride, temperature, ORP.• 2 stations installed: 1 spring box (Padang, June ‘11), 1 shallow well (Bonga, March ‘11). PHIVOLCS scientists trained.• Bimonthly data downloads, battery service (soon solar), calibration.• Telemetry pending completion of antenna masts (under way, contracted), and installation of solar panels (delivered) & GSM modem. event event event Calibration offset
Multidisciplinary monitoring of Mt. Mayon, Luzon, Philippines Part 2 – Geophysical Monitoring D Hidayat1, F M Schwandner1, S Marcial1, C Newhall1, E Laguerta2, R Vaquilar2, A Baloloy2, R Valerio2
GPS data from PHIVOLCS-GPS working group have 1. Mayon volcano: Background activityyielded phases of precursory ground displacementprior to eruptive activity in 2006 and 2009. Data courtesy of (PHIVOLCS).Plots of relative distance changes between stations suggest inflation due to magmaintrusion in late 2005; followed by apparent deflation in early to mid 2006.Renewed inflation began again in late 2007 to early 2008; followed by extrusion ofmagma in the December 2009 eruption.Besides showing evidence of surface ground deformation from volcanic origin, theobserved GPS signal around Mayon also showing local tectonic origin (Bacolcol, pers.comm.).
3. Tectonic settingsTectonically, Mayon is located in the Bicol Basin (Oas Graben), a northwest trendingstructural depression. Structural analysis of previous study reveals a regionaltranstensional stress regime in the Bicol basin, which induced the northwest strikingleft-lateral faults to have a normal slip component (Lagmay et al., 2005).The Oas Graben bounded by Legaspi Lineament to the north and San Vicente Linao Faultto the south. The Legazpi Lineament (N70oW) is seismically active and is a left-lateralfault with a normal component to the east (Le Rouzic, 1999). GPS data analysis (Ranginet al., 1999) derived a left-lateral motion of 13 mm/yr along the Legaspi Fault with 13mm/yr of extension perpendicular to it.
4. Geophysical MonitoringCurrently there are 4 broadbandseismographs, 3 short periodinstruments (PHIVOLCS-NEID;which recently upgraded tobroadband instrument), and 5tiltmeters. These instruments willbe telemetered to the Lignon HillVolcano Observatory through radioand 3G broadband internet.
5. Self-made low-cost data loggerWe also make use of our self-made low-cost tiltmeterdatalogger which has beenoperating since Jan 2011,performing data acquisitionwith sampling rate of 20minute/sample and transmittedthrough gsm network as textmessage.We also designed and assembled a high data-ratedatalogger and tested it with short period seismic andtilt instrument at Mayon, Gede and Salak volcanoes.The datalogger can also be used for other analogsensors such as microphones, microbarographs andothers. It is equipped with GPS for accurate time.We are using one type of 5.8 GHz radio telemetry in our volcano laboratories. The 5.8 GHzis growing in use due to low cost, versatility, and no frequency license requirementcompared to 900 MHz, but it does not have the flexibility of a lower-frequency system toshoot through vegetation and around corners.An alternative solution for telemetry from remote location to EOS data center without toworry about line of sight is using a new device: a 3G modem integrated with a router thatcan link to internet service provided by cellular companies.
PHIVOLCS Monitoring Data Schema Lignon Hill ManilaVolcano Observatory Earth Observatory of Singapore swarm Seiscomp Earthworm Earthworm INTERNET PICOT NOVAC Hydrolab Trillium Applied Geomechanics GeospaceCO2 & met SO2 MS5: Wells compact 701-(4X) Mini Seis-monitor Trimble NetR8
Currently there are 4 broadbandseismographs, 3 short periodinstruments (PHIVOLCS-NEID;which recently upgraded tobroadband instrument), and 5tiltmeters. These instruments willbe telemetered to the Lignon HillVolcano Observatory through radioand 3G broadband internet.
6. Preliminary ResultsUnderstanding on what structures active deformation is occurring and howdeformation signal is currently partitioned between tectonic and volcanic origin is akey for characterizing magma movement in the time of unrest.Preliminary analysis of the tangential components of tiltmeters (particularly thestations VMDB and VMAB, NE of the volcano) shows gradual inflation movementover several months period. The tangential components for tiltmeters are roughlyperpendicular to the fault north of Mayon. This may suggest downward tilting of thegraben in the northern side of Mayon. Another possibility is that the magmaticsystem under Mayon is asymmetrical.With the additional 2 instruments recently installed, we have better azimuthaltiltmeter coverage around the volcano, which permitted us to monitor any possiblesurface ground deformation coming from either volcanic and tectonic origin.This hypothesis can be verified later.
6. Preliminary ResultsWe perform 3D forward modeling (flat surface/no topo) of a left-lateral strike slip fault with normal component(mimicking Legaspi lineament movement as describe by GPS solution of Rangin et al.1999). Parameters: strike N65W;dip 80 (westward); left lateral motion: 13mm; dip-slip: 13mm.The main idea was to check whether the observed tangential tilt is compatible with the movement of LegaspiLineament. We can see consistency of the observed tangential tilt to the model .Note: positive tangential-tilt trend = counterclockwise movement. VMDB and VMAB positive trend = downward movement of the block northwestward of these stations (footwall of Legaspi Lineament downward)
6. Preliminary ResultsEarthquakes in the area reflect both Mayon volcanic activity and its adjacenttectonic activity. High quality of hypocenter location is essential. Before detailedstudy of volcano-related seismic events, our broadband seismograph study willrefine a velocity model underneath the volcano with the analysis of receiverfunctions of teleseismic earthquakes. Such information can be also used to betterformulate a coherent regional tectonic model and help characterize the seismicsources in the region. Our study presents the depth of Moho and crustal velocitystructure including low velocity zones, which hint the depth of magma bodies.
6. Preliminary ResultsIn the spectrum from openly-degassed to plugged volcanoes, Mayon is near theopenly-degassing end, producing mostly small and frequent eruption.An EOS-PHIVOLCS collaboration is initiated in 2010 with effort to develop amulti-disciplinary monitoring system around Mayon includes geophysicalmonitoring, gas geochemical monitoring, and petrologic studies.Short and modest seismic and gas precursors to recent eruptions of Mayon. GPSdata analysis yielded precursory inflation for 2006 and 2009 eruption. However,the deformation signals were affected much by the deformation due totectonics.Combined analysis of multi-parameter geophysical data will enable thepossibility to locate and quantified the fault movement adjacent to Mayon,isolate seismic and deformation signal related to volcanic origin, for betterunderstanding magmatic system of Mayon volcano.
FY2011 EOS-CVGHM geophysical monitoring network1. Established geophysical network (3 broadband, 3 short-period, and 2 tiltmeter stations installed and operating)2. Data connection through GSM and radio telemetry; continuous data stream to Gede observatory with sampling rate: 100sps (BB & SP) and 1 sample per 20 minutes (Tilt)3. Self-made low cost data logger was tested and now functioning permanently for tiltmeter and short period4. In progress: real time data display (observatories, CVGHM-Bandung and EOS)
Gede and Salak Monitoring StatusGede-2 broadband stations are installed, permanent house already built-1 repeater stations is built, 1 repeater housed in Telkomsel cellular tower-1 short period station is installed-2 short period stations are planned: 1 will be in SW of Gede (before 31/03/12), 1will be at the summit (~May 2012)-2 tiltmeterS are installed and co-located with broadband seismometers: 1 will berelocate from north to south station by 31/03/12.Salak-2 short period stations are installed: 1 with permanent house is recently built-1 broadband station is installed between Salak and Pangrango; this can servedata for Gede as wellTelemetry-Radio network is built for both Gede and Salak-for station with difficult line of sight, 3G internet is used for data telemetry-Each at the observatory post there is a server where data are accessible viainternet for CVGHM and EOS. Realtime data display can be achieved, delayeddata backup at EOS is being implemented. Enhancement of internet speed willbe implemented by 31/03/12 for realtime data display and backup at EOS.
Temporary seismic and tilt installation at station N of Gede Volcano
Permanent seismic and tilt installation at station S of Gede Volcano
Repeater station installation for Gede and Salak Volcanoes
Earthquake Locations at and around Gede Volcano
Earthquake Locations at and around Gede Volcano, cont.-These are locatable tectonic and volcanic earthquakes from May-Oct 2011 withS-P less than 5 sec.-Several earthquakes occurred beneath Gede crater with depth 0-5km-Several earthquake occurred along Cimandiri fault-Sequences of small earthquakes (depth range 0-15 km) occurred NE Gede andSW of Gede (Cluster 1 and 2), over the time of recordings, many occurred alongSW-NE across Gede and Pangrango.-We postulates that there is (are) faults running across Gede-Pangrangoconnecting Cimandiri fault and Lembang fault (NE or Gede). Similar swarmsoccurred in 1997 were located between Gede and Pangrango.-Earthquake hypocenters are still preliminary, velocity structure refinement willimprove locations probably clustered more than currently shown.