supplemental ngeo2239 s1
SUPPLEMENTARY INFORMATION
DOI: 10.1038/NGEO2239
Lusi mud eruption triggered by geometric focusing
of seismic waves
M. Lupi, E. H. Saenger, F. Fuchs and S. A. Miller
−700
−1000
−800
−1500
−2000
−900
Vs
−2500
Vp
Volcanics
−1000
b)
Pucangan Formation
(Alluvial)
−500
Depth, m
Depth (m)
a)
Bluish Gray Clay
−600
0
−1100
Vp
380 m/s
−3000
0
1000
2000
3000
4000
Velocity (m/s)
5000
−1200
1400
1600
1800
2000
Velocity (m/s)
Supplementary Figure 1. Measured Vp and Vs profiles (a) from the BJP-1 borehole. The Vp record
extends to about 300 m depth, while the Vs record does not begin until the casing shoe at about
1100 m depth. Notice that Vs is about 380 m/s in the mud layer. A zoom-in of a portion of the record
(b) shows increasing Vp with depth above the mud layer, between about 700 m and 875 m depth
(blue line), indicative of a normally compacting horizon. A reduction in Vp at depths from 875 m to
1150 m indicates significantly reduced effective stress from the over-pressured and
under-consolidated mud layer.
NATURE GEOSCIENCE | www.nature.com/naturegeoscience
1
SUPPLEMENTARY INFORMATION
Vp/Vs=2.25
Vp/Vs=4.5
Vp/Vs=8.75
Vp/Vs=2.7
DOI: 10.1038/NGEO2239
Supplementary Figure 2. Experimental data showing large reductions in Vp/Vs ratios with increasing
effective stress. We used the measured Vp of 2000 m/s at the top of the mud layer to estimate a Vs of about
750 m/s at this boundary. The recorded S-wave velocity of 380 m/s in the mud layer (Vp/Vs=4.5,
supplementary fig 4) indicates low effective stress representative of an under-consolidated and
over-pressured horizon, typically referred to as low-velocity zones. Modified from [Lee, 2010].
2
NATURE GEOSCIENCE | www.nature.com/naturegeoscience
Seismic Line Su-24
Seismic Lines in the Vicinity of Banjar Panji-1
Seismic Line B-91-124
SUPPLEMENTARY INFORMATION
DOI: 10.1038/NGEO2239
Supplementary Figure 3. The complete montage of the well log recorded for the BJP1 borehole. In our original study,
we interpreted the top of the mud layer to exist at about 1,100 m depth based on a published velocity profile. However,
well log data recorded at borehole BJP1 show that the mud layer begins at ~900 m and we have adjusted our analyses
and interpretations accordingly.
NATURE GEOSCIENCE | www.nature.com/naturegeoscience
3
SUPPLEMENTARY INFORMATION
DOI: 10.1038/NGEO2239
−1000
−1200
−1400
Depth (m)
−1600
−1800
−2000
−2200
−2400
−2600
−2800
1
2
3
Vp/Vs
4
5
Supplementary Figure 4. Measured Vp/Vs ratios showing persistently elevated ratios of
about 4.5 within the mud layer indicative of a low effective stress (high pore pressure)
environment.
4
NATURE GEOSCIENCE | www.nature.com/naturegeoscience
DOI: 10.1038/NGEO2239
SUPPLEMENTARY INFORMATION
Lee, M.W., (2006c), A simple method of predicting S-
Lee , M. W. (2010), Predicting S-5138.
of the Mechanics and Physics of Solids, v. 35, p. 213 226.
Zimmer, M.A., (2003), Seismic velocities in unconsolidated sands―Measurements of
NATURE GEOSCIENCE | www.nature.com/naturegeoscience
5
DOI: 10.1038/NGEO2239
Lusi mud eruption triggered by geometric focusing
of seismic waves
M. Lupi, E. H. Saenger, F. Fuchs and S. A. Miller
−700
−1000
−800
−1500
−2000
−900
Vs
−2500
Vp
Volcanics
−1000
b)
Pucangan Formation
(Alluvial)
−500
Depth, m
Depth (m)
a)
Bluish Gray Clay
−600
0
−1100
Vp
380 m/s
−3000
0
1000
2000
3000
4000
Velocity (m/s)
5000
−1200
1400
1600
1800
2000
Velocity (m/s)
Supplementary Figure 1. Measured Vp and Vs profiles (a) from the BJP-1 borehole. The Vp record
extends to about 300 m depth, while the Vs record does not begin until the casing shoe at about
1100 m depth. Notice that Vs is about 380 m/s in the mud layer. A zoom-in of a portion of the record
(b) shows increasing Vp with depth above the mud layer, between about 700 m and 875 m depth
(blue line), indicative of a normally compacting horizon. A reduction in Vp at depths from 875 m to
1150 m indicates significantly reduced effective stress from the over-pressured and
under-consolidated mud layer.
NATURE GEOSCIENCE | www.nature.com/naturegeoscience
1
SUPPLEMENTARY INFORMATION
Vp/Vs=2.25
Vp/Vs=4.5
Vp/Vs=8.75
Vp/Vs=2.7
DOI: 10.1038/NGEO2239
Supplementary Figure 2. Experimental data showing large reductions in Vp/Vs ratios with increasing
effective stress. We used the measured Vp of 2000 m/s at the top of the mud layer to estimate a Vs of about
750 m/s at this boundary. The recorded S-wave velocity of 380 m/s in the mud layer (Vp/Vs=4.5,
supplementary fig 4) indicates low effective stress representative of an under-consolidated and
over-pressured horizon, typically referred to as low-velocity zones. Modified from [Lee, 2010].
2
NATURE GEOSCIENCE | www.nature.com/naturegeoscience
Seismic Line Su-24
Seismic Lines in the Vicinity of Banjar Panji-1
Seismic Line B-91-124
SUPPLEMENTARY INFORMATION
DOI: 10.1038/NGEO2239
Supplementary Figure 3. The complete montage of the well log recorded for the BJP1 borehole. In our original study,
we interpreted the top of the mud layer to exist at about 1,100 m depth based on a published velocity profile. However,
well log data recorded at borehole BJP1 show that the mud layer begins at ~900 m and we have adjusted our analyses
and interpretations accordingly.
NATURE GEOSCIENCE | www.nature.com/naturegeoscience
3
SUPPLEMENTARY INFORMATION
DOI: 10.1038/NGEO2239
−1000
−1200
−1400
Depth (m)
−1600
−1800
−2000
−2200
−2400
−2600
−2800
1
2
3
Vp/Vs
4
5
Supplementary Figure 4. Measured Vp/Vs ratios showing persistently elevated ratios of
about 4.5 within the mud layer indicative of a low effective stress (high pore pressure)
environment.
4
NATURE GEOSCIENCE | www.nature.com/naturegeoscience
DOI: 10.1038/NGEO2239
SUPPLEMENTARY INFORMATION
Lee, M.W., (2006c), A simple method of predicting S-
Lee , M. W. (2010), Predicting S-5138.
of the Mechanics and Physics of Solids, v. 35, p. 213 226.
Zimmer, M.A., (2003), Seismic velocities in unconsolidated sands―Measurements of
NATURE GEOSCIENCE | www.nature.com/naturegeoscience
5