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Italian Journal of Engineering Geology and Environment - Book www.ijege.uniroma1.it © 2011 Casa Editrice Università La Sapienza
623
DOI: 10.4408/IJEGE.2011-03.B-068
THE PRESENT DEVELOPMENT OF DEBRIS FLOW MONITORING
TECHNOLOGY IN TAIWAN – A CASE STUDY PRESENTATION
H
siao
-y
uan
YIN
(*)
, C
HinG
-J
eR
HUANG
(**)
,
C
HenG
-y
u
CHEN
(***)
, y
ao
-m
in
FANG
(****)
,
b
inG
-J
ean
LEE
(*****)
& t
ien
-y
in
CHOU
(*******)
(*)
Section Chief, Soil and Water Conservation Bureau, Council of Agriculture, Nantou 540, Taiwan
Email: sammya@mail.swcb.gov.tw)
(**)
Department of Hydraulic and Ocean Engineering, National Cheng-Kung University, Tainan 701, Taiwan
(***)
Director of Debris Flow Disaster Prevention Center, Soil & Water Conservation Bureau, Council of Agriculture, Nantou 540, Taiwan
(****)
Geographic Information System Research Center, Feng Chia University, Taichung 40724, Taiwan
(*****)
Department of Civil Engineering, Feng Chia University, Taichung 40724, Taiwan
(******)
Department of Land Management, Feng Chia University, Taichung 40724, Taiwan
INTRODUCTION
Taiwan’s steep topographical features, young and
weak geological formations, earthquakes, erodible
soils and heavy rainfall cause landslides and debris
flows on the island, which often result in extensive
human lives and property losses. Although there were
quite a few debris flow events in the past few years, lit-
tle field observation data were obtained from actual de-
bris flow hazards. The lack of field data might result in
slow research progress of debris flows. To improve the
capability of collecting field data, the Soil and Water
Conservation Bureau (SWCB), Council of Agriculture
has started the debris flow monitoring project since
2002. So far, 17 on-site and 3 mobile debris flow moni-
toring stations have been established around Taiwan.
Various studies have investigated the debris flow
observation works. w
u
et alii (1990) observed vari-
ous characteristics and mechanism of debris flows at
the Jiangjia Gully observation and research station,
Yunnan Province, China. A lot of field debris flow
data were recorded and several real-time warning
systems were proposed using precipitation, ground
vibrations and ultrasonic mud-level measurements.
b
eRti
et alii (2000) mentioned the field monitoring
system installed in Acquabona Creek in the Dolo-
mites (Eastern Italian Alps). A double threshold
controlled by the geophone signals and rain inten-
sity is adopted for the switch between two different
operation modes. l
aviGne
et alii (2000) used rain
gauges and various ground vibration sensing sys-
ABSTRACT
In order to document the on-site debris flow
events, the Soil and Water Conservation Bureau
(SWCB), Council of Agriculture, Taiwan, has de-
voted to develop the debris flow monitoring system
since 2002. This paper introduces the technology of
17 on-site and 3 mobile debris flow monitoring sta-
tions established by SWCB in Taiwan. In each on-site
monitoring station, several observation instruments
including rain gauges, CCD cameras, wire sensors,
geophones, and water level meters were installed to
collect the dynamic debris flow information that can
be used as the references for countermeasures of de-
bris flow disaster mitigation. Besides, several mete-
orological sensors are also adopted recently in order
to record the long-term climate change effects on the
slopeland of Taiwan. The framework of the debris
flow monitoring system consists of monitoring sen-
sors, instrumental cabin (vehicle platform for mobile
station), transmission system and web-based display
system. During the typhoon Mindulle period in 2004,
a debris flow event in Aiyuzih creek was observed by
the Shenmu debris flow monitoring station on July 2,
Nantou County, central Taiwan. On-site observation
data including the rainfall patterns, video images, wire
sensor ruptures and ground vibrations caused by de-
birs flows are analyzed in detail.
K
ey
word
: debris flows, debris flow monitoring system, mobi-
le debris flow monitoring station
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5th International Conference on Debris-Flow Hazards Mitigation: Mechanics, Prediction and Assessment Padua, Italy - 14-17 June 2011
primary observation sensors including rain gauges,
infrared CCD (charge-coupled device) cameras, wire
sensors, geophones and an ultrasonic water level me-
ter are adopted to detect debris flows. Recently, sev-
eral meteorological sensors such as light meters, ther-
mo-hydrometers, anemometers, wind direction vanes,
soil moisture probes and barometers are put to use in
order to record the long-term effects of climate change
on the slopeland of Taiwan.
In the field, all the observation data detected by
tems to monitor more than 50 volcanic debris flows
or lahars generated around Mount Merapi in Indone-
sia. m
aRCHi
et alii (2002) discussed the debris flow
monitoring works in the Moscardo Torrent (Italian
Apls). The monitoring system consists of different
sensors was adopted to measure the rainfall, flow
stage and ground vibrations caused by debris flows.
H
üRlimann
et alii (2003) discussed the field data
of debris flows events occurred at the Swiss Alps.
The real-time data of debris flows were gathered
by debris-flow observation stations equipped with
video cameras, ultrasonic devices, a radar device,
geophones, and rain gauges. b
adoux
et alii (2008)
described debris-flow detection and alarm systems
using a wide range of detection sensors for the Al-
pine Illgraben catchment, Switzerland. In Taiwan,
l
iu
& C
Hen
(2003) developed an integrated debris
flow monitoring system with various sensors. They
classified the operation of the integrated debris flow
monitoring system into three stages according to dif-
ferent criteria of the rain gauge, ground water level
and ground vibrations. y
in
et alii (2007a) introduced
the establishment and various specifications related
to the debris flow monitoring system in Taiwan. The
main purpose of this paper is to introduce the frame-
work and operation mechanism of the on-site and
mobile debris flow monitoring stations established
by the SWCB in Taiwan. In 2004, a debris flow
event in Aiyuzih creek caused by typhoon Mindulle
on July 2 was recorded by the Shenmu debris flow
monitoring station. The field observation data are
analyzed and discussed in detail herein.
ON-SITE DEBRIS FLOW MONITORING
STATION
The framework of the on-site debris flow monitor-
ing station mainly consists of monitoring sensors, the
instrumental cabin, the transmission system and the
web-based display system. In Taiwan, the current 17
on-site debris flow monitoring stations are located at
the vicinity of potential debris flow torrents which are
prone to debris flows as shown in Fig. 1 and Table 1.
According to the survey of SWCB, there are 1552 po-
tential debris flow torrents around Taiwan island. The
investigation of these torrents is primarily based on
the features of the hydrology, geography, geology and
protected objects (population and/or infrastructure) in
the field. Originally, in each monitoring station, five
Fig. 1 - Distribution of 17 on-site debris flow monitoring
stations in Taiwan
Fig. 2 - Instrumental cabin of Jiufen-ershan station in
Nantou County.
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THE PRESENT DEVELOPMENT OF DEBRIS FLOW MONITORING TECHNOLOGY IN TAIWAN – A CASE STUDY PRESENTATION
Italian Journal of Engineering Geology and Environment - Book www.ijege.uniroma1.it © 2011 Casa Editrice Università La Sapienza
625
the web-based display system-the debris flow disas-
ter prevention information system (http://246.swcb.
gov.tw) which is a decision-making support system
providing disaster information for commanders and
operators to make decisions during the emergency
response stages. It also allows the public to in-
quire different slopeland information for precaution
against landslide and debris flow disasters.
Two operation modes -“normal mode” and “event
mode” were originally designed in the monitoring
system according to the rainfall condition in the field.
During the “normal mode” in usual times, the sam-
pling rate of the monitoring devices is at low frequen-
cy. When the rain gages pick up rainfall data exceed-
ing the proposed thresholds (rainfall intensity exceeds
10 mm/hr or accumulated rainfall exceeds 100 mm
within 24 hours), the “event mode” is triggered. All
sensors are upgraded to higher sampling rate to detect
field observation data. At the same time, the system
automatically sends a triggering signal to crew of the
debris flow emergency response task force of SWCB
by mobile telecommunication system for further nec-
essary emergency response actions.
the monitoring sensors will be transmitted to the
on-site instrumental cabin through wire or wireless
ways for preliminary data processing. Usually the
instrumental cabin, as shown in Fig. 2, is situated
at a relatively safer place near the objective poten-
tial debris flow torrent. The cabin made of concrete
has two rooms for the information instruments and
power supply circuit. The primary (domestic power
110 voltages) and back-up (battery sets and diesel-
electric generator) power modules keep the monitor-
ing station operating constantly especially during
the typhoon period. After preliminary process and
storage, the observation data in the instrumental
cabin are transmitted through the satellite (primary
transmission, 256 Kb/s) to the SWCB. In case the
satellite communication failure occurs, several back-
up transmission modules including the asymmetric
digital subscriber line (ADSL), the domestic and the
mobile telecommunication can be utilized to trans-
mit the monitoring data to the SWCB at the lower
transmission speed. All the real-time information
transmitted from the on-site and/or mobile debris
flow monitoring stations to SWCB is illustrated on
Tab. 1 - Debris flow monitoring stations of SwCB
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5th International Conference on Debris-Flow Hazards Mitigation: Mechanics, Prediction and Assessment Padua, Italy - 14-17 June 2011
toring data of wire sensors and the rain gauge during
the debris flow occurrence are shown in Fig. 7. The
10-minute rainfall intensity before the debris flow
surge (4:41 pm) was 5.5 mm (also the peak 10-minute
rainfall intensity), and the accumulated rainfall
reached 182 mm at the moment of the debris flow oc-
currence. Wu et alii (1990) concluded that water is not
only the major ingredient of debris flows but also a
determinant of debris flow occurrence. They use the
10-minute rainfall intensity and the preceding rainfall
as the indices to develop the debris flow forecasting
model in Jingjia Gully, Yunnan Province, China. b
eRti
et alii (2000) analyzed the field observation data and
proposed that high intensity rainfall in a short period
of time is the major cause of debris flow occurrence.
They also mentioned the probable correlation between
debris flows and peak 10-minute rainfall intensity. In
Aiyuzih creek, two sets of wire sensors were installed
at the same cross-section near the pier of Aiyuzih
bridge. The lower one (2 m above the riverbed) broke
at 09:16 am on July 2 because of the raised water level
in the channel (hyper-concentrated flood observed
from the images of CCD camera). The upper one (3
m above the riverbed) broke at 4:41 pm, July 2, under
the impact of the front surge of debris flows (also ob-
served from the images of CCD camera). Comparison
between the timing of wire sensor rupture and the im-
age data indicates that the break of wire sensor can-
not precisely represent debris flows (sometimes the
hyper-concentrated floods or drift wood). Thus, wire
sensors result limited in detecting the occurrence of
debris flows. It is also found that when the wire sen-
sor was broken (9:16 am by the floods and 4:41 pm
by the debris flows on July 2), the 10-minute rainfall
also reached the peak intensity (5.5 mm). Therefore,
DEBRIS FLOW OBSERVATION DATA -
DEBRIS FLOW EVENT ON JULY 2, 2004
SHENMU DEBRIS FLOw MONITORING STATION
At the end of June, 2004, typhoon Mindulle at-
tacked Taiwan and was accompanied by strong south-
west air current with heavy precipitation and caused
severe floods and landslides in mountain areas espe-
cially in central Taiwan. From the statistics of central
emergency operation center, typhoon Mindulle re-
sulted in 41 casualties and 89 billion NT dollars agri-
cultural loss in the whole country. On July 2, a debris
flow detected by the Shenmu debris flow monitoring
station was bursting in Aiyuzih creek. In this paper,
the observations and preliminary interpretations of
monitoring data from a representative debris flow
event detected by Shenmu station are discussed in de-
tail. Shenmu station is located at the upstream area of
Hoshe creek, a branch of Chenyoulan river in Shenmu
Village, Nantou County. Due to the presence of two
faults passing through this area, the down-cutting of
the riverbed is severe, the bedrock is weak and unsta-
ble, and active landslides as well as debris avalanches
scatter among the watershed. Three branches includ-
ing Chushuei creek, Housa creek, and Aiyuzih creek
merge at Shenmu Bridge and flow into the Hoshe
creek as shown in
Fig. 3. Among them, Chushuei and
Aiyuzih creeks are monitored at the same time. The
debris flow event described in this paper occurred in
Aiyuzih creek which is characterized by severe land-
slides, a high degree of sediment transport and debris
flow activities. The landslide rate in Aiyuzih creek
catchment is 2.57% as shown in Fig. 4. The length
of the main Aiyuzih creek is 3810 m with an average
slope of 11.5 degrees. The catchment area is 410 ha.
Among the catchment, 93.4% of the area is character-
ised by a slope angle over 30%. The elevation of the
catchment ranges from 2100 m a.s.l. to 1150 m a.s.l..
The layout of the monitoring instruments of Shenmu
station is shown in Fig. 3.
RAIN GAUGE AND wIRE SENSORS
From July 2 to 5, the accumulated rainfall meas-
ured by Shenmu station reached 1254 mm compared
with the average annual rainfall of Taiwan-2450 mm.
From the CCD camera, the largest debris flow event
was observed at 4:41 pm on July 2 in Aiyuzih creek.
The preceding rainfall was 14 mm within 15 hours
(from July 1, 3:00 pm to July 2, 6:00 am). The moni-
Fig. 3 - Layout of monitoring instruments in Shenmu
station
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THE PRESENT DEVELOPMENT OF DEBRIS FLOW MONITORING TECHNOLOGY IN TAIWAN – A CASE STUDY PRESENTATION
Italian Journal of Engineering Geology and Environment - Book www.ijege.uniroma1.it © 2011 Casa Editrice Università La Sapienza
627
the riverbed was scoured 2 to 3 m in depth. From
the video images of Aiyuzih creek, several typical
debris flow characteristics were identified such as a
very low discharge just before the first surge, the ac-
cumulation of large boulders at the debris flow front,
the obvious wavy surface of the surges, and a rapid
decrease of the flow depth behind the front. Those
findings accord with the debris flow characteristics
presented by t
akaHasHi
(1991) including: (1) the
forefront looks like a bore and the depth of the flow
increases abruptly at the front; (2) the biggest stones
accumulate at the forefront; (3) behind the front of
the flow, the flow appears like a mud flow of gradu-
ally decreasing discharge. Besides, some specific pa-
rameters of debris flows in Aiyuzih creek are derived
from those video images. The average velocity of
debris flow front surge was about 13 m/s. The maxi-
mum particle size of the debris was about 4 to 5 m.
The flowing depth of the front surge was between 5.5
to 6 m while the average depth of the debris flow was
2 m. The debris flows continued for about 5 minutes
depositing approximately 77,400 m
3
of sediments.
we speculate that high intensity rainfall during a short
period of time is the major cause of flash floods or
debris flows.
CCD CAMERAS
Fig. 5 shows the image of debris flow surge in
Aiyuzih creek. From the image data we noticed that
shortly before the occurrence of the debris flow, how-
ever, the flow discharge in the channel was drasti-
cally reduced. It may be assumed that somewhere in
the upstream area, the landslide probably occurred,
blocking the channel temporarily. Meanwhile, the
upstream water level was still rising, saturating the
temporary dam. Unable to resist the water pressure,
the dam composed of loose soil and rocks finally col-
lapsed and turned into debris flows flushing down-
stream. The debris flows in the Aiyuzih creek not
only incised the riverbed but also destroyed, with
powerful lateral erosive forces, almost all the dry
masonry bank revetments (about 5 m in height) and
the abutment of Aiyuzih bridge as shown in Fig. 6.
The channel width was widened from 36 m to 80m,
Fig. 4 - Aerial photo of Aiyuzih creek catch-
ment
Fig. 5 - Debris flow image in Aiyuzih creek, Shenmu station
Fig. 6 - (a) River bank erosion by debris flows in Aiyuzih
creek
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5th International Conference on Debris-Flow Hazards Mitigation: Mechanics, Prediction and Assessment Padua, Italy - 14-17 June 2011
Geophones
i
veRson
(1997) described that debris flows are
rapid, gravity-induced flows of mixtures of rocks,
mud and water. Materials composing the debris flows
rolled over, scrubbed and hit the riverbed as they
flowed down the creek, causing significant ground
vibrations. t
akaHasHi
(1991) pointed out that debris
flows are accompanied by loud noises and the ground
vibrates violently. These ground vibrations are also
known as underground sounds, or geosounds, and are
speculated to be generated by the collision of large
boulders with the channel bed, especially near the
front of debris flows. Along the Aiyuzih creek, three
geophones were installed along the riverbank. How-
ever, the upstream one was buried by sediments ear-
lier. During the debris flow event on July 2, 2004, only
the midstream and downstream geophones ranging
at a distance of 173 meters were usable as shown in
Fig. 3. The sampling rate of each geophone is 500 Hz
nthree directions simultaneously. The ground vibra-
tions are three-dimensional with velocity amplitudes
that roughly the same along three directions. For brev-
ity, only ground vibrations in one direction are pre-
sented in this paper. The time-domain signals of the
ground vibrations generated by debris flows were con-
verted into the frequency domain by the Fast Fourier
Transform (FFT) and into the time-frequency domain
using the Gabor Transform after H
uanG
et alii (2007)
and y
in
et alii (2007b). Fig. 8 displays the ground vi-
bration analysis of the debris flow measured by the
midstream geophone at 4:41 pm on July 2 in Aiyuzih
creek. As can be seen from Fig. 8(a), the time domain
signals reveal that at 4:41:38 pm the midstream geo-
phone first detected the significant ground vibration,
and at 16:41:44, the velocity amplitude reached its
maximum. Subsequently, the midstream geophone
installed inside the dry masonry bank revetment was
washed away under the impact of the debris flow and
then caused some false signals. From Fig. 8(b) and
8(c), frequencies of debris flow ground vibrations
measured in the Aiyuzih creek are within 250 Hz and
mainly in the range of 5 to 100 Hz. In particular, it is
obvious at around 60 Hz, where the spectra have mul-
tiple peak values. This is corroborated by the litera-
tures (o
kuda
et alii, 1980; w
u
et alii, 1990; t
unGol
& R
eGalado
(1997); i
takuRa
et alii, 1997; l
aviGne
et
alii, 2000); H
uanG
et alii,2007 and y
in
et alii, 2007b)
stating that the frequency of ground vibrations gener-
ated by debris flows is relatively low-mainly between
10 and 100 Hz and occasionally exceeds 100 Hz.
Besides the image analysis, a
RRatano
(2003) pre-
sented another effective way to figure out the mean
velocity of debris flow front surge using the serial de-
ployment of geophones along the torrent. In the time
domain, the peak velocity of the ground vibration sig-
nals indicates that the front surge of the debris flow is
at the nearest location to the geophone (also that the
debris flow has reached this site). The time lag between
the peak amplitude of the two consecutive geophones
signals allows the mean velocity of the debris flow
front surge to be estimated. The distance between the
fig 6(b) - Abutment damage of Aiyuzih bridge due to debris
flows
Fig. 7 - wire sensor and
rainfall data dur-
ing debris flow pe-
riod on July 2, 2004,
Shenmu station
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THE PRESENT DEVELOPMENT OF DEBRIS FLOW MONITORING TECHNOLOGY IN TAIWAN – A CASE STUDY PRESENTATION
Italian Journal of Engineering Geology and Environment - Book www.ijege.uniroma1.it © 2011 Casa Editrice Università La Sapienza
629
as shown in Fig. 9
.
Basically, the framework of mobile
debris flow monitoring station is similar to the on-site
station except for the specially designed lightweight in-
struments and the vehicle platform replacing the instru-
mental cabin. In order to extend the observation scope,
the SWCB recently has developed the module sensors
composed of wireless transmission, battery sets and
portable devices for debris flow monitoring. So far, sev-
eral modules sensors were manufactured including the
rain gauge, wire sensors and CCD cameras as shown
in Fig. 10. The module sensors can be equipped with
either the on-site or the mobile debris flow monitoring
stations through the wireless transmission techniques
especially for the upstream areas monitoring where the
landslides and debris flows usually initiate.
.
CONCLUSIONS
The 17 on-site and 3 mobile debris flow monitoring
stations established by SWCB have opened a new ap-
proach of debris flow observation in Taiwan. From the
developing experiences and field observation data anal-
ysis, the following conclusions are presented herein:
The main purpose of the debris flow monitoring
system is to collect field debris flow data as much as
possible. The precious monitoring information can
be utilized not only for helping us to understand the
physical mechanism of debris flows, but also to im-
prove the accuracy of the current debris flow warning
system based on rainfall thresholds.
The rupture of wire sensors cannot precisely rep-
resent debris flows (sometimes the hyper-concentrat-
ed floods or drift wood). In other words, wire sensors
have limits in detecting the occurrence of debris flows.
From the analysis of 10-minute rainfall pattern,
wire sensors rupture time and debris flow occurrence
time, we speculate that high intensity rainfall during
midstream and downstream geophones is 173 m. Deter-
mined from the foregoing technique, the mean velocity
of the debris flow front was 13.3 m/s according with
the result of the dynamic image analysis obtained from
CCD cameras (13 m/s). Another finding during the
debris flow process is that the intensity of the ground
vibration signals recorded by the midstream geophone
(installed in the dry masonry bank revetment) is about
10 times higher than that of the downstream geophone
(located in the concrete bank revetment). It seems that
the geophone in the dry masonry bank revetment is
more sensitive to pick up the ground vibrations. We
speculate that the location of the geophone has consid-
erable influence on the signal intensity of the ground
vibrations generated by debris flows.
MOBILE DEBRIS FLOW MONITORING
STATION AND MODULE SENSORS
Usually, the debris flow events in Taiwan are in-
duced by typhoons accompanying heavy precipitation
during the flood season (May to November). Since the
typhoon routes are variable, debris flows events do not
always occur at the sites where the debris flow monitor-
ing stations locate. In order to enhance the probability
of detecting the debris flow events, the SWCB has de-
voted to the research of mobile debris flow monitoring
station since 2004. The mobile debris flow monitoring
station, as implied by the name, is the mobility evolu-
tion from the original fixed on-site debris flow monitor-
ing station. When the Central Weather Bureau issues
the forecast of incoming typhoon, the mobile debris
flow monitoring stations are sent to the site of high-
est probability of debris flow occurrence on the basis
of a prediction model founded on typhoon routes and
rainfall distribution prediction. Up to now, 3 mobile de-
bris flow monitoring stations have been accomplished
Fig. 8 - Ground vibration signals of debris flow monitored by the midstream geophone on July 2, 2004 in Aiyuzih
creek
;
(a) time domain siganls, (b) spectrum of FFT, and (c) spectrum of Gabor transform
background image
H.-Y. YIN, C.-J. HUANG, C.-y. cheN, y.-m. FANG, B.-J. LEE & t.-y. CHOU
630
5th International Conference on Debris-Flow Hazards Mitigation: Mechanics, Prediction and Assessment Padua, Italy - 14-17 June 2011
a short period of time is probably the major cause of
flash floods and debris flows.
From the video images of debris flows in Aiyuzih
creek, several debris flow characteristics were apparent
such as a very low discharge just before the first surge,
the accumulation of large boulders at the debris flow
front, the obvious wavy surface of the surges, and a
rapid decrease of the flow depth behind the front.
Frequencies of debris flow ground vibrations
measured in Aiyuzih creek are within 250 Hz and
mainly in the range of 5 to 100 Hz. In particular, it is
obvious at around 60 Hz, where the spectra have mul-
tiple peak values. This is corroborated by other litera-
tures stating that the frequency of ground vibrations
generated by debris flows is relatively low.
The average velocity of debris flow front surge
from dynamic image measurement (13 m/s) accords
with the result from ground vibration signal analysis
using the serial deployment of geophones (13.3 m/s)
along the Aiyuzih creek. It is implied that both CCD
cameras and geophones can be used as the estimation
of mean velocity of debris flow front surges.
Fig. 9 - Mobile debris flow monitoring station
Fig. 10 - Modules of the rain gauge and CCD camera
REFERENCES
a
Rattano
, m., (2003) - Monitoring the presence of the debris-flow front and its velocity through ground vibration detectors, The
Third Int. Conf. on Debris-Flow Hazards Mitigation: Mechanics, Prediction, and Assessment, Davos, Switzerland: 719-730.
b
adoux
a., G
Raf
C., R
HyneR
J., k
untneR
R. & m
C
a
Rdell
b.w. (2008) - A debris-flow alarm system for the Alpine Illgraben
catchment: design and performance. Nat. Hazards, 49: 517-539.
b
eRti
m., G
enevois
R., l
aHusen
R., s
imoni
a. & t
eCCa
P.R. (2000) - Debris flow monitoring in the Acquabona watershed on the
Dolomites (Italian Alps). Phys. Chem. Earth(B), 25(9): 707-715.
H
uanG
C.J., y
in
H.y., C
Hen
C.y., y
eH
C.H. & w
anG
C.l. (2007) - Ground vibrations produced by rock motions and debris flows,
J. Geophys, Res., 112, F02014, doi:10.1029/2005JF000437, pp. 1-20.
H
uRlimann
m., R
iCkenmann
d. & G
Raf
C. (2003) - Field and monitoring data of debris-flow events in the Swiss Alps. Can.
Geotech. J., 40: 161-175.
i
takuRa
y., k
amei
n., t
akaHama
J. i. & n
owa
y. (1997) - Real time estimation of discharge of debris flow by an acoustic sensor,
14th IMEKO World Congress, New Measurements - Challenges and Visions, Tampere, Finland, XA: 127-131.
i
veRson
R.m., (1997) - The physics of debris flows. Reviews of Geophysics, 35: 245-296.
l
aviGne
f., t
HouRet
J.C., v
oiGHt
b., y
ounG
k., l
a
H
usen
R., m
aRso
J., s
uwa
H., s
umaRyono
a., s
ayudi
d.s. & d
eJean
m.,(2000) - Instrumental lahar monitoring at Merapi Volcano, Central Java, Indonesia. Journal of Volcanology and Geo-
thermal Research, 100: 457-478.
l
iu
k.f. & C
Hen
, s.C, (2003) - Integrated debris-flow monitoring system and virtual center. The Third Int. Conf. on Debris-Flow
Hazards Mitigation: Mechanics, Prediction, and Assessment, Davos, Switzerland, 767-774.
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THE PRESENT DEVELOPMENT OF DEBRIS FLOW MONITORING TECHNOLOGY IN TAIWAN – A CASE STUDY PRESENTATION
Italian Journal of Engineering Geology and Environment - Book www.ijege.uniroma1.it © 2011 Casa Editrice Università La Sapienza
631
m
aRCHi
l., a
Rattano
m. & d
eGanuti
a.M. (2002) - Ten years of debris-flow monitoring in the Moscardo Torrent (Italian Alps).
Geomorphology, 46: 1-17.
o
kuda
s., o
kunisHi
k. & s
uwa
H. (1980) - Observation of debris flow at kamikamihori Valley of Mt. Yakedade. In Excursion
Guidebook of the 3rd Meeting of IGU commission on Field Experiment in Geomorphology, Disaster Prev. Res. Inst. Kyoto
Univ., Japan, pp. 127-130.
t
akaHasHi
t. (1991) - Debris Flow. Int. Assoc. for Hydraul. Res. Monogr. Rotterdam: Balkema.
t
unGol
n.m. & R
eGalado
m.t. (1997) - Rainfall, acoustic flow monitor records and observed lahars of the Sacobia River in
1992. In n
ewHall
C.G. & P
unonGbayan
R.s. (
eds
.). Fire and Mud: Eruptions and Lahars of Mt. Pinatubo, Philippines.
Seatle University of Washington Press: 1023-1032.
w
u
J.s., k
anG
z.C., t
ian
l.C. & z
HanG
s.C. (1990) - Observation and investigation of debris flows at Jiangjia Gully in Yun-
nan Province. Dongchuan debris flow observation station. Chinese Academy of Science, Science Press, Beijing, China [in
Chinese].
y
in
H.y., l
in
y.i, l
ien
J.C., l
ee
b.J., C
Hou
t.y. f
anG
y.m., l
ien
H.P. & C
HanG
y.H. (2007a) - The study of on-site and mobile
debris flow monitoring station. 2nd International Conference on Urban Disaster Reduction, Taipei, Taiwan, November 27-
29: 113.
y
in
H.y., H
uanG
C.J., C
Hen
C.y., y
eH
C.H., l
ee
b.J., f
anG
y.m. & C
HanG
y.H. (2007b) - Monitoring ground vibrations gen-
erated by debris flows. The 4
th
Int. Conf. on Debris-Flow Hazards Mitigation: Mechanics, Prediction, and Assessment,
Chengdu, China: 625-633.
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