1. 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

2. 1. Mayon volcano: Background activity
2. Geochemical Monitoring
3. Tectonic settings
4. Geophysical Monitoring
5. Self-made low-cost data logger
6. Preliminary results

3. • 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.

4. 1. Mayon volcano: Background activity
Mayon is an openly-degassed basaltic-andesitic volcano, rises to 2,462m above Albay Gulf
in the Philippines.
Considered the most active volcano in the Philippines, Mayon produce small eruptions
every 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 and
pyroclastic flows.
In the spectrum from openly-degassed to plugged volcanoes,
Mayon is near the openly-degassing end, producing mostly small and frequent eruptions.
b

5. 1. Mayon volcano: Background activity
Relatively 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

6. 1. Mayon volcano: Background activity
In the latest eruption, a small explosion on early Dec 11, 2009 was followed by spilling
of 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 minor
explosive 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).

7. 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 light
gray 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 activity
during this interval.
Data courtesy of (PHIVOLCS).

8. • 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.

9. Mayon monitoring network

10. Mayon hazard zonation:
6-km no settlement zone

11. Mayon hazard zonation:
6-km no settlement zone
…and lahars

12. 2. Geochemical monitoring
Mayon conceptual geochemical monitoring design
GOSAT
OMI, TOMS, …

13. Gas Geochemistry:
flank CO2 as early unrest indicator

14. 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

15. 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)

16. Gas Geochemistry:
flank CO2 as early unrest indicator
Multisensor 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.

17. 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 HQ
One 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.

18. Hydrology / Geochemistry:
Strain and flank degassing monitoring
Wells 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

19. 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

20. GPS data from PHIVOLCS-GPS working group have 1. Mayon volcano: Background activity
yielded phases of precursory ground displacement
prior to eruptive activity in 2006 and 2009.
Data courtesy of (PHIVOLCS).
Plots of relative distance changes between stations suggest inflation due to magma
intrusion 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 of
magma in the December 2009 eruption.
Besides showing evidence of surface ground deformation from volcanic origin, the
observed GPS signal around Mayon also showing local tectonic origin (Bacolcol, pers.
comm.).

21. 3. Tectonic settings
Tectonically, Mayon is located in the Bicol Basin (Oas Graben), a northwest trending
structural depression. Structural analysis of previous study reveals a regional
transtensional stress regime in the Bicol basin, which induced the northwest striking
left-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 Fault
to the south. The Legazpi Lineament (N70oW) is seismically active and is a left-lateral
fault with a normal component to the east (Le Rouzic, 1999). GPS data analysis (Rangin
et al., 1999) derived a left-lateral motion of 13 mm/yr along the Legaspi Fault with 13
mm/yr of extension perpendicular to it.

22. 4. Geophysical Monitoring
Currently there are 4 broadband
seismographs, 3 short period
instruments (PHIVOLCS-NEID;
which recently upgraded to
broadband instrument), and 5
tiltmeters. These instruments will
be telemetered to the Lignon Hill
Volcano Observatory through radio
and 3G broadband internet.

23. 4. Geophysical Monitoring

24. 5. Self-made low-cost data logger
We also make use of our self-
made low-cost tiltmeter
datalogger which has been
operating since Jan 2011,
performing data acquisition
with sampling rate of 20
minute/sample and transmitted
through gsm network as text
message.
We also designed and assembled a high data-rate
datalogger and tested it with short period seismic and
tilt instrument at Mayon, Gede and Salak volcanoes.
The datalogger can also be used for other analog
sensors such as microphones, microbarographs and
others. 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 GHz
is growing in use due to low cost, versatility, and no frequency license requirement
compared to 900 MHz, but it does not have the flexibility of a lower-frequency system to
shoot through vegetation and around corners.
An alternative solution for telemetry from remote location to EOS data center without to
worry about line of sight is using a new device: a 3G modem integrated with a router that
can link to internet service provided by cellular companies.

25. PHIVOLCS Monitoring Data Schema
Lignon Hill Manila
Volcano Observatory Earth Observatory
of Singapore
swarm
Seiscomp
Earthworm Earthworm
INTERNET
PICOT NOVAC Hydrolab Trillium Applied Geomechanics Geospace
CO2 & met SO2 MS5: Wells compact 701-(4X) Mini Seis-monitor Trimble NetR8

26. Currently there are 4 broadband
seismographs, 3 short period
instruments (PHIVOLCS-NEID;
which recently upgraded to
broadband instrument), and 5
tiltmeters. These instruments will
be telemetered to the Lignon Hill
Volcano Observatory through radio
and 3G broadband internet.

27. 6. Preliminary Results

28. 6. Preliminary Results

29. 6. Preliminary Results
Understanding on what structures active deformation is occurring and how
deformation signal is currently partitioned between tectonic and volcanic origin is a
key for characterizing magma movement in the time of unrest.
Preliminary analysis of the tangential components of tiltmeters (particularly the
stations VMDB and VMAB, NE of the volcano) shows gradual inflation movement
over several months period. The tangential components for tiltmeters are roughly
perpendicular to the fault north of Mayon. This may suggest downward tilting of the
graben in the northern side of Mayon. Another possibility is that the magmatic
system under Mayon is asymmetrical.
With the additional 2 instruments recently installed, we have better azimuthal
tiltmeter coverage around the volcano, which permitted us to monitor any possible
surface ground deformation coming from either volcanic and tectonic origin.
This hypothesis can be verified later.

30. 6. Preliminary Results
We 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 Legaspi
Lineament. 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)

31. 6. Preliminary Results
Earthquakes in the area reflect both Mayon volcanic activity and its adjacent
tectonic activity. High quality of hypocenter location is essential. Before detailed
study of volcano-related seismic events, our broadband seismograph study will
refine a velocity model underneath the volcano with the analysis of receiver
functions of teleseismic earthquakes. Such information can be also used to better
formulate a coherent regional tectonic model and help characterize the seismic
sources in the region. Our study presents the depth of Moho and crustal velocity
structure including low velocity zones, which hint the depth of magma bodies.

32. 6. Preliminary Results
In the spectrum from openly-degassed to plugged volcanoes, Mayon is near the
openly-degassing end, producing mostly small and frequent eruption.
An EOS-PHIVOLCS collaboration is initiated in 2010 with effort to develop a
multi-disciplinary monitoring system around Mayon includes geophysical
monitoring, gas geochemical monitoring, and petrologic studies.
Short and modest seismic and gas precursors to recent eruptions of Mayon. GPS
data analysis yielded precursory inflation for 2006 and 2009 eruption. However,
the deformation signals were affected much by the deformation due to
tectonics.
Combined analysis of multi-parameter geophysical data will enable the
possibility to locate and quantified the fault movement adjacent to Mayon,
isolate seismic and deformation signal related to volcanic origin, for better
understanding magmatic system of Mayon volcano.

33. FY2011 EOS-CVGHM geophysical monitoring network
1. 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 period
4. In progress: real time data display (observatories, CVGHM-Bandung and EOS)

34. Gede and Salak Monitoring Status
Gede
-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), 1
will be at the summit (~May 2012)
-2 tiltmeterS are installed and co-located with broadband seismometers: 1 will be
relocate 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 serve
data for Gede as well
Telemetry
-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 via
internet for CVGHM and EOS. Realtime data display can be achieved, delayed
data backup at EOS is being implemented. Enhancement of internet speed will
be implemented by 31/03/12 for realtime data display and backup at EOS.

36. Temporary seismic and tilt installation at station N of Gede Volcano

37. Permanent seismic and tilt installation at station S of Gede Volcano

38. Repeater station installation for Gede and Salak Volcanoes

39. Earthquake Locations at and around Gede Volcano

40. Earthquake Locations at and around Gede Volcano, cont.
-These are locatable tectonic and volcanic earthquakes from May-Oct 2011 with
S-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 and
SW of Gede (Cluster 1 and 2), over the time of recordings, many occurred along
SW-NE across Gede and Pangrango.
-We postulates that there is (are) faults running across Gede-Pangrango
connecting Cimandiri fault and Lembang fault (NE or Gede). Similar swarms
occurred in 1997 were located between Gede and Pangrango.
-Earthquake hypocenters are still preliminary, velocity structure refinement will
improve locations probably clustered more than currently shown.