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www.earthobservatory.sg

Remote infrasound in SE-Asia: A case study of the 2014 Kelud eruption and minimum detection threshold through space and time

Ash cloud image after A. Tupper, Australia Bureau of Meteorology [2002]

Volcanic Ash and Air Traffic When are we blind when are we deaf ?

VEI 2VEI 3

VEI 4

Detections (circles) and non-detections (crosses) of volcanic infrasound from 110 eruptions occurring at 39 globally distributed volcanoes. The most distant detection is highlighted by �lled black circles. The dashed lines represent the linear best-�t line to the maximum detected distances only. From Dabrowa et al. [2012], EPSL. Horizontal lines represents the plume elevation for VEI 2, 3 and 4.

8 days average cloud cover over South East Asia in June 2014 (ranging between 0 (no clouds) and 1 (fully covered)). Black dots are di�erent volcanic zones. Source: http://neo.sci.gsfc.nasa.gov/ (Modis product)

0°

10°

-10°

100° E 120° E

Flight line

Potential ash producing volcano

Ash cloud (1979-2010)

Ash-airplane encounter

Infrasound network (Bukit Timah)

Polar plot highlighting azimuth and distance of each volcanic zones with respect to Singapore. The proposed study will allow an automated detec-tion of strong volcanic activity, and trigger a set of ash dispersal simulations that will be re�ned as informa-tion is collected.

Simulations of the minimum pressure detectable by one array of the IMS infrasound network complemented or not by Singapore Network. Maps are calculated for the same day with/without Singapore station for zone 4 (above) and 14 (below)

1000 km~50 min

2000 km~100 min

3000 km~150 min

4000 km~200 min Active Volcanic zone

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ce an

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Quiet Volcanic zone

Satellite Infrasound

Detection tresholds at 0.4 Hz. for a Signal to Noise Ratio of 0.1 Factor of improvement achieved by adding Singa-pore to IMS for zone IV (blue) and zone XIV (black)

Infrasound array in Singapore

Infrasound Array (5 sensors)

On the use of remote infrasound and seismic stations to detect volcanic eruptionsCase study: 2014 Kelud eruption

Attenuation [dB]

80oE 100oE 120oE 140oE 160oE 40oS

30oS

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Kelud volcano (Central Java, Indonesia, cyan triangle on (a) and (b)). (a) Seismic detections: the pies are divided in three and correspond to the broadband sensors detections (IRIS and GEOFON networks) used in this study. Infrasound detec-tions: the half pies are the infrasound stations (IMS network). White colors correspond to a non detection, green to the de-tection of S_P1, blue of S_LL, red of S_P2, magenta of I_1 and yellow of I_LL. (a) zoom on the region of interest (b) global de-tections.

Signal recorded at GE-UGM (Yogyakarta, Central Java, Indonesia, 198 km from Kelud volcano). (a) Spectro-gram of signals having a high Signal to Noise Ratio (SNR, in dB, where the noise is considered as the energy averaged over the record at each frequency band) (b) raw spectrogram (c) corresponding seismo-gram. (a) and (b) are computed using 6th octave bands and 1/f window scaling with a 75% overlap (dB re 1 micron/s). A tectonic earthquake (EQ) is indicated on the plot (b).

Predicted attenuation map of the acoustic signal (central frequency of 0.06 Hz and using European Centre for Medium-Range Weather Forecasts (ECMWF) wind conditions) using parabolic equation numericalmodelling [Le Pichon et al., 2012)

Future perspectives for next year

Network resolution Azimuth error

1

2

3

STA1

InstallationSingapore: Redvox array

Marapi (Sumatra, Indonesia):3 di�erent technologies experiment:Redvox (ISLA, Hawai’i)Uni� (Firenze University)Infra BSU (Boise University)

Gede (Java, Indonesia):5 sensors array

Redvox Inc: A project from M.A. Garces, ISLA

Zone IV (Sumatra)

Caudron, C., Taisne, B., Garcés, M., Le Pichon, A., & Mialle, P. (2015). On the use of remote infrasound and seismic stations to constrain the eruptive sequence and intensity for the 2014 Kelud eruption. Geophysical Research Letters, 42(16), 6614-6621.

20 % of the time, improvement treshold of:- 3.5 in zone IV- 1.25 in zone XIV

UNIFI sensors

Infra BSU

UNIFI + Redvox

Marapi volcanoSumatra (Indonesia)

Gede volcanoJava (Indonesia)

Redvox system

2005 2006 2007 2008 2009 2010 2011 2012 2013 20140

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Zone XIV (Sulawesi)

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tion 9 years time serie for zone XIV

9 years time serie for zone IV

Review on the detection capability of two remote sensing techniques: Satellite and Infrasound.We focus our analysis on South East Asia where climatic conditions are challenging both techniques.

‘Ideal’ situationSource: http://neo.sci.gsfc.nasa.gov/

Most frequent situationSource: http://neo.sci.gsfc.nasa.gov/

Zone IV (Sumatra) Zone XIV (Sulawesi)

(a)

(b)

No seismic detection

Infrasound

Seismic

Latitude

Latitude

LongitudeLongitude

SP_1SP_2

S_LL

I_1I_LL No infrasound detection

~3 km/s

~0.3 km/s

The di�erent arrivals altogether as a function of the distance with respect to Kelud volcano.

In App Store

REDVOXINFRASOUNDRECORDER

Japan

Korea

Singapore

Kilauea, Hawaii

Old Faithful, Yellowstone

Indonesia

10 days of PSDs recorded at STA1 between 1-10 August 2015 (green curves: noise models /red curve: median of the 1-hr curves displayed in black)

Results of preliminary PMCC analysis for the Thai bolide recorded in Singapore on 7 September 2015 (time is in UTC and origin time ~01:45 UTC)

Presented by B. Taisne1,2, C. Caudron1, M. Garces3, A. Le Pichon3,, P. Mialle3

1 Earth Observatory of Singapore 2 Asian School of the Environment 3 Infrasound Laboratory, Hawaii,USA4 CEA/DAM/DIF, Arpajon, France 5 CTBTO, Vienna, Austria

http://www.redvoxsound.com/

Zone IV

Zone XIV