Keywords: Catastrophic landslide triggered debris 
flow; Dynamic process; Main controlling factors; 
Tendency analysis; Yigong.

Palabras clave: deslizamienos de tierra ocasionados 
por flujos de detritos; procesos dinámicos; factores 
principales de control; análisis de tendencias; 
Yigong.

How to cite item
Li, J., Chen, N., Zhao, Y., Liu, M., & Wang, 
W. (2020). A catastrophic landslide triggered 
debris flow in China’s Yigong: factors, dynamic 
processes, and tendency. Earth Sciences 
Research Journal, 24(1), 71-82. DOI: https://
doi.org/10.15446/esrj.v24n1.78094

A disaster of a catastrophic landslide triggered a debris flow with a scale of 0.3 billion m3 that occurred in the 
Zhamunong gully of Yigong on April 9th, 2000. It is of great scientific and engineering significance to study  
the main controlling factors and dynamic processes of this disaster, and the future development trend of similar hazards. 
Firstly, the precipitation, earthquake and temperature data before the event and seismic wave data after the event were 
collect. Secondly, a multi-dimensional approach on the data for finding the factors, dynamic processes and tendency of 
a catastrophic landslide triggered a debris flow in Zhamunong gully was applied, including the standard precipitation 
index and effective peak acceleration calculation methods, fast Fourier transform, landslide stability, MacCormack-
TVD finite difference method and FLAC numerical simulation method. The results are shown as follows. (1) The 
main controlling factors of this disaster were the long-term freeze-thaw cycle, dry-wet cycle, and a middle magnitude 
earthquake. (2) Based on the ground vibration spectrum of 2000 disaster recorded by the Linzhi seismic station, the 
dynamic processes are the joint and crack development process, the crack fracture and sliding process, the landslide 
translating into the debris flow, the movement and deposition of the debris flow. (3) The density and the average 
velocity are 2.0 t·m-3 and 30.12 m·s-1, respectively, and the discharge is shown with the process of first increases and 
then decreases. (4) Similar catastrophic landslide triggered debris flow would happen in Zhamunong gully in the 
future. The research results are useful in establishing a foundation for further study on the dynamic mechanism and 
reduction countermeasures of a catastrophic landslide triggered by debris flow.

ABSTRACT

A catastrophic landslide triggered debris flow in China’s Yigong: factors, dynamic processes, and tendency

Deslizamiento de tierra ocasionado por el flujo de detritos en el río Yigong (China): factores, procesos dinámicos y tendencia

ISSN 1794-6190 e-ISSN 2339-3459         
https://doi.org/10.15446/esrj.v24n1.78094

Un deslizamiento de tierra ocasionó un flujo de detritos a una escala de 0.3 miles de millones de metros cúbicos en 
la hondonada de Zhamunong en el río Yigong, el 9 de abril de 2000. El estudio de los factores deteterminantes y las 
dinámicas del proceso de este desastre, al igual que el estudio de la tendencia a futuro de eventos similares, ha sido 
de gran importancia científica e ingenieril. Inicialmente, se recolectó la información relacionada con la precipitación, 
terremotos y temperatura antes del deslizamiento y la información de onda sísmica después del evento. Luego se 
realizó un acercamiento multidimensional a la información para encontrar los factores, los procesos dinámicos y la 
tendencia del deslizamiento de tierra que desencadenó un flujo de detritos en Zhamunong, y que incluyó el índice de 
precipitación regular y los métodos de cálculo de aceleración sísmica, transformada rápida de Fourier, estabilidad 
de un deslizamiento, el método de las diferencias finitas MacCormack-TVD y el método de simulación numérica 
FLAC. Los resultados muestran lo siguiente: (1) Los factores de control principal del deslizamiento fueron el ciclo 
a largo plazo de congelación y descongelación, el ciclo de humedad y sequía, y un terremoto de magnitud media. 
(2) Con base en el espectro de vibración del terreno registrado durante este evento por la estación sísmica de Linzhi, 
las dinámicas pasan por el desarrollo del proceso de agrietamiento y articulación, el proceso de agrietamiento de las 
fracturas y deslizamiento, la traslación del deslizamiento de tierra en flujo de detritos, el movimiento y la deposición 
de estos detritos. (3) La densidad y el promedio de velocidad son de 2.0 t·m-3 y 30.12 m·s-1, y la descarga se muestra 
con el proceso de primero incremento y luego disminución. (4) Eventos similares pueden ocurrir en la hondonada de 
Zhamunong a futuro. Los resultados de la investigación son útiles para establecer los cimientos de estudios posteriores 
en los mecanismos de dinámicas y en la reducción de contramedidas de deslizamienos de tierra ocasionados por flujos 
de detritos.

RESUMEN

Record
Manuscript received: 26/02/2019
Accepted for publication: 18/10/2019

EARTH SCIENCES 
RESEARCH JOURNAL

Earth Sci. Res. J. Vol. 24, No. 1 (March, 2020): 71-82

Jun Lia, Ningsheng Chenb*, Yuandi Zhaoa, Mei Liub, Weiyu Wanga

1School of Civil Engineering, Sichuan University of Science & Engineering, Zigong, 643000, China
2Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China

* Corresponding author: chennsh@imde.ac.cn

G
EO

TE
CH

NI
CA

L 
EN

G
IN

EE
RI

NG



72 Jun Li, Ningsheng Chen, Yuandi Zhao, Mei Liu, Weiyu Wang

Introduction

A Catastrophic Landslide Triggered Debris Flow (CLDF) refers to a  
chain of landslides with a volume of more than 1×107 m3 transforming to  
a high-speed and long distant debris flow after detaching from the parent rock 
due to the landslide’s enormous potential energy (Huang and Fan, 2013, Chen et 
al., 2018, Samodra et al., 2018). At 20:00:11.95 on April 9th, 2000 (Local time), 
a catastrophic landslide triggered debris flow that occurred in the Zhamunong 
gully in Yigong (Wang and Lu, 2002, Shang et al., 2003, Evans and Delaney, 
2011). The landslide struck the ground, leading to loosening bed depositions 
mixed in the landslide in the headstream of the gully, then the landslide 
transformed into a debris flow by the soil liquefaction. The deposits carried by 
the debris flow blocked the Yigong Zangbo river. The subsequent barrier dam 
outbreak on June 10th then fast formed a flash flood, which resulted in heavy 
casualties and economic losses (Kang et al., 2017, Wang and Li, 2017, Liu 
and He, 2018). In China, the flash flood damaged 318 National Road, Tongmai 
Bridge, the Motuo Jiefang Bridge, highways, among others. The G318 national 
highway was broken off for 76 days, which resulted in two people causalities 
and a loss of 280 million Yuan (Liu, 2000, Lu, 2002, XuQiang et al., 2012, 
Schmidt et al., 2015). Besides, the flash flood killed 94 people, 2.5 million 
people were homeless in Ramaphotra, northern India, and traffic broke off in 7 
central Indian states (Tewari, 2004, Wang et al., 2016). 

Many local and international scholars have studied this catastrophic 
disaster. Scholars have already studied the scale characteristics of the 2000 
CLDF in the Zhamunong Gully and the macroscopic processes that occur 
when a landslide transfers into a debris flow; results show that this CLDF is 
triggered by rainfall and that the deposit volumes range from 1.2 to 3.0×108 

m3 (Shang et al., 2003, Xu et al., 2012, Evans and Delaney, 2011, Delaney and 
Evans, 2015). Meanwhile, a more large-scale debris flow occurred in the same 
place in 1902 (Shang et al., 2003). However, the following issues in the above 
studies need to be researched: (a) CLDFs led by rainfall are generally small-
scale (Wang and Sassa, 2003, Guzzetti et al., 2009, Chen et al., 2010). Previous 
studies show that freeze-thaw cycles, dry-wet cycles, and seismic linkages are 
extremely conducive to the development of CLDFs (Chen et al., 2014, Zhou 
et al., 2016, Huang et al., 2016) and that rainfall is a decisive factor for the 
occurrence of a CLDF (Chen et al., 2016, Deng et al., 2017). Additionally, a 
Ms 4.3 earthquake might influence the occurrence of a landslide (Delgado et 
al., 2011). Is the occurrence of the 2000 CLDF related to the middle and small 
earthquakes, the freeze-thaw cycles and the dry-wet cycles in the region? (b) 
Studies on the dynamic process of landslides transforming into debris flows are 
not well understood, so it is necessary to perform a quantitative study on these 
dynamic processes. (c) The process of volume changes of CLDFs over long 
timescales are the basis for analyzing the development tendency of the CLDF 
in the Zhamunong Gully, but this research has yet to be published.

Due to the construction demand for major projects, such as town, roads, 
and hydropower, the practical demands of disaster prevention and reduction 
(Wang et al., 2018a, 2018b), and the scientific problem of surface denudation 
processes at the edge of the Tibetan Plateau, the main purpose of this paper is 
to study the main controlling factors on and dynamic processes and tendency of 
the CLDF in the Zhamunong Gully. To tackle the aforementioned issues, a case 
study is performed based on the 2000 CLDF in the Zhamunong Gully. Section 
2 describes the study area and methodology. Section 3 and section 4 address the 
main controlling factors and the dynamic processes of the CLDF, respectively. 
Section 5 analyzes the development tendency of CLDF, and Section 6 presents 
the conclusions. The technical flowchart is shown in Figure 1.

Study area and methodology

Study area

The Zhamunong Gully is located in the northwest region of the Namcha 
Barwa Peak and is on the left bank of the Yigong Zangbo River (Fig. 2a). 
Topographic variations are acute along the western and eastern margin, forming 
an alpine landform. The basin area is 29.4 km2. The highest and lowest altitudes 
are 5616.00 m and 2185.72 m, respectively. The relative relief is 3430.28 m. 
The average gradient is 233 ‰, and the largest gradient is 646 ‰. The regional 
climate is relatively warm with an average temperature of 6°C~17°C and a mean 
disproportionate annual precipitation of 1225.8 mm. The precipitation curve is 
shaped like a double peak (referring to the months of May-June and August-
September). The lithology from north to south are Himalayan granite (outcrop 
altitude elevation between 4100 m-5616 m), limestone, slate and marble of 
the Carboniferous system (outcrop altitude elevation between 2800 m-4100 
m), and gneiss and schist of the Gangdese group from the pre-Sinian system 
(outcrop altitude elevation between 2198 m-2800 m). The Zhamunong Gully 
is crossed by three fault zones (Fig. 2b), which are the Jiali Deep Fault Zone 
(F1), the Dade-Anizha Fault (F22), and the Danen-Zepu Fault (F3), where the 
seismic activity of the Jiali Fault is comparatively frequent with the occasional 
occurrence greater than Ms 6 earthquakes (Lee et al., 2003; Song et al., 2013)

Methodology

Standard Precipitation Index (SPI) and Effective Peak Acceleration 
(EPA) calculation methods

We estimate the influence of earthquakes by using EPA method in Table 1.  
The Yigong landslide is within Western China, therefore, the model for 
computing the EPA is based on the empirical model between earthquakes and 
seismic acceleration in Western China (Wang and Shi, 1993, Yu and Gao, 2001). 
The drought grade shown in Table 2 is based on the SPI (Chen et al., 2014).

Compilation of basic 

Dynamic processes of the 2000 

Tendency of 

Mechanical test 
data for granite 

Particle size 2000 CLDF Precipitation,
temperature,

earthquake data

Landslide stability 
analysis 

Characteristic parameters 
of dynamic processes

Dynamic
processes 

Main controlling factors

Figure 1. Technical flowchart.



73A catastrophic landslide triggered debris flow in China’s Yigong: factors, dynamic processes, and tendency

(Mccubbine et al., 2017). FFT analysis converts a signal from its original domain 
to a representation in the frequency domain. The parameters of frequency, 
amplitude, and peak ground parameters (such as acceleration and displacement) 
are transformed from the seismic wave based on the Seismosignal software 
from the website of https://www.seismosoft.com/seismosignal-prod.

Landslide stability

The calculation equation for the locking section length of a landslide is 
shown in Equation 1. Equations 2-6 are the detailed calculation equations of  
every force in Equation 1. In Equations 1-6, F is the stability coefficient  
of the landslide; F=1 is a critical stable state of landslide (that is, the landslide is 
near sliding when F=1); FK is the anti-sliding force, in KN/m; FS is the sliding 
force, in KN·m-1; c is the cohesion force of the rock mass in the sliding surface 
of the landslide, in Kpa; φ is the internal friction angle of the rock mass in 
the sliding surface of the avalanche mass, in º; L is the length of the locking 
section (the non-perforated length of the landslide’s fissure surface), in m; 
V is the fissure water pressure, in KN·m-1; U is the uplift pressure along the 

Table 2. Dry grade based on the SPI

Dry grade Type SPI Occurrence frequency

1 No drought -0.5<SPI 68%

2 Slight drought -1.0<SPI≤-0.5 15%

3
Moderate 
drought

-1.5<SPI≤-1.0 10%

4 Heavy drought -2.0<SPI≤-1.5 5%

5
Special 
drought

SPI≤-2.0 2%

Fast Fourier transform

A fast Fourier transform (FFT) is an algorithm that samples a signal 
over a period of time (or space) and divides it into its frequency components 

Figure 2. Geological map of the Yigong region.

Table 1. Attenuation equation for the EPA in Western China

EPA EPA EPAw w sw= ⋅1

where R is the sensitive radius and 
M is the magnitude.

Longitudinal direction
Acceleration attenuation equation

EPA M IM1 2 492 0 786 2 787 3 269 0 4510w R
=

+ + ( ) . . . log . exp .

Short direction
Acceleration attenuation equation

EPA M IMsw R
=

+ + ( ) 101 093 0 59 1 794 1 046 0 45. . . log . exp .

https://www.seismosoft.com/seismosignal-prod


74 Jun Li, Ningsheng Chen, Yuandi Zhao, Mei Liu, Weiyu Wang

slip surface, in KN·m-1; Q is the earthquake force, in KN·m-1; ζ is the level 
coefficient of the earthquake; α is the dip of the sliding surface; W is the weight 
of the landslide, in KN·m-1;  is the density of granite rock masses, in kg·m-3; 
v is the volume of landslide, in m3; g is the acceleration of gravity; h is the 
depth of the fissure in the trailing edge, in m; and hw is the water-filling height 
of the fissure in the trailing edge, in m, which ranges between 0.2 h in natural 
time and 0.3-0.5 h during a rainstorm. As per rainfall data, there was heavy 
rainfall before the BH01 landslide happened, so hw is valued 0.5 h. Hcr is the 
depth of the fissure in the landslide’s trailing edge, in m. H is the height of the 
slope from the front of the landslide to the trailing edge of the fissure, in m. The  
rock mass is comparatively broken at the source of the Zhamunong Gully;  
the internal friction angle’s reduction factor for the BH01 landslide’s rock mass 
is 0.8, and the internal friction angle of the avalanche mass’s sliding surface after 
reduction is 46.616°, according to the Technical Specification for Construction 
Slope Engineering, China (DB50/330-2002). When the cracking segment of 
the rock mass in the landslide’s trailing edge cracks to 363 m and the front 
locking section transfixes, the landslide reaches a limit equilibrium state. Table 
3 summarizes the calculation parameters.

F F
F

W Q U tg cL
W Q V

K

s
= ==

( ) × +
+ +

cos sin
sin cos cos
α− α− φ

α α α
 (1)

V hw w= ×0 5 2.      (2)

U Lhw w= ×0 5.      (3)

Q W=       (4)

W vg
L

=       (5)

H Hcr = 0 5763 27 0092. .    (6)

Table 3. Calculation parameters for landslide stability

Parameters (Units) Values Parameters (Units) Values

Density of Granite  

(kg·m-3)
2640

Level coefficient  
of earthquake ζ

0.255

Density of Water γw 
(KN·m-3)

10 Dip of sliding surface α (°) 36.5

Cohesion strength c (Kpa) 9690 Hcr (m) 363

Internal friction angle φ (°) 46.616 hw (m) 181.5

A MacCormack-TVD finite difference method

The MacCormack-TVD finite difference method proposed by (Ouyang, 
et al., 2013) can be used to simulate the dynamic process of CLDFs. Therefore, 
this method is suitable for calculating the discharge of the 2000 CLDF. The  
boundary condition is the wall boundary condition; the base model is  
the Coulomb friction model, and the corresponding Coulomb friction coefficient 
is set as 0.215. The coefficient of earth pressure is set to constant 1. Equations 
7-10 based on this method are shown as follows.

∂
∂

+ ∂
∂

+ ∂
∂

− =( ) ( ) ( )  


h
t

hu
x

hv
y

E1 1 0   (7)

∂
∂

+
∂

∂
+

∂
∂

−
+( )( ) ( ) ( )ρ ρ ρ

ρ
h
t

hu
x

hu v
y

g h k g h
h Z
x

uu uu
x z

b1 1
2

1 1β β
− ρ

∂

∂
− ττ ρ1 1zx b bu E( ) +

∂
∂

+
∂

∂
+

∂
∂

−
+( )( ) ( ) ( )ρ ρ ρ

ρ
h
t

hu
x

hu v
y

g h k g h
h Z
x

uu uu
x z

b1 1
2

1 1β β
− ρ

∂

∂
− ττ ρ1 1zx b bu E( ) +    

(8)

∂
∂

+
∂

∂
+

∂
∂

−
+( )( ) ( ) ( )ρ ρ ρ

ρ
hv
t

hu v
x

hv
y

g h k g h
h Z
x

uv vv
y z

b1 1 1 1
2β β

− ρ
∂

∂
−− τ ρ1 1zy b

bu E( ) +

∂
∂

+
∂

∂
+

∂
∂

−
+( )( ) ( ) ( )ρ ρ ρ

ρ
hv
t

hu v
x

hv
y

g h k g h
h Z
x

uv vv
y z

b1 1 1 1
2β β

− ρ
∂

∂
−− τ ρ1 1zy b

bu E( ) +    

(9)

E
t

hvzb= =
∂

∂
α     (10)

In equations 7-10, x, y, z are the direction of debris flow movement; t 
is the move time, in s;  is the density of the debris flow, in kg/m3; h is the 
depth of the debris flow, in m; 

1
 and v1 are the velocity of the movement 

directions x and y, respectively, in m/s; 1zx b( )  and 1zy b( )   are the drag base of 

the movement directions x and y; (gx, gz) are the gravitational acceleration in the 
movement directions x and z;  is the momentum distribution coefficient; k is 
the coefficient of earth pressure; E is the basal erosion rate of the debris flow; v 
is the point velocity, in m/s; and  is the erosion rate coefficient.

The initial and boundary conditions 

FLAC numerical simulation method based on the shear strength 
reduction for calculating future landslide magnitude using parameters from 
rock mechanics tests

The Fast Lagrangian Analysis of Continua (FLAC) method is suitable 
for simulating landslide sliding surfaces, so we use this method to estimate  
the volume of future similar landslides to analyze the tendency of CLDFs. The 
FLAC numerical simulation method is used for estimating the longitudinal 
area of potential landslides BH01 and BH02 under extreme conditions (Fig. 
3a). The FLAC numerical simulation method is a fast Lagrangian difference 
method based on shear strength reduction (Jing et al., 2008). The shear strength 
reduction is expressed by the change of safety coefficient. The actual calculation 
process of the safety coefficient Fs is in Equation 11. The implementation 
processes of shear strength reduction in FLAC are shown as follows. When 
some strength reduction coefficient RF is such that the plastic zone of the 
sliding surface completely transfixes in the computed processes of FLAC,  
the strength reduction coefficient RF is the value of the safety coefficient 
Fs. The FLAC method uses the history display of finite difference time. For 
each time step, the main calculation process is completed by (1) calculating 
the new strain rate from the node velocity in Equation 12, (2) calculating the 
stress of the previous step using the constitutive equation through the strain 
rate in equation 13 and equation 14 and equation 15, and (3) deriving the new 
node velocity and displacement from the stress and force through the motion 
equation in equation 16. Each time step repeats the above three steps to monitor 
the maximum unbalanced force. When the maximum unbalanced force equals 
a constant, we have estimated the plastic rock masses in the landslide profile. 
Besides, the initial and boundary conditions of the FLAC method contain the 
surface force, concentrated load, and displacement boundary, and the physical 
strength and initial stress conditions also need to be applied. At the beginning of 
the computer program, all stresses and node velocities are set to zero, and then 
we apply the initial stress. The concentrated load is assigned to the node on the  
surface, and the displacement boundary condition is precisely controlled by  
the velocity of the node. The physical force and the surface force are transformed 
into a series of equivalent node loads in the interior. The above constitutes the 
initial state of numerical calculation. Moreover, we considered the earthquake 
intensity of 5 degrees in the computed process of the FLAC method to simulate 
the actual seismic situation of Zhamunong gully.

The simulation profiles of the BH01 and BH02 potential landslides are 
shown in Fig. 3b. The dip angles of the main granite joints are 211° and 163° in 
the BH01 and BH02 potential landslides, respectively; the granite rock masses 
with those dip angles easily form slides, so the simulation profile direction is 
the same as the dip directions. The depths of the BH01 and BH02 potential 
landslides are obtained using the FLAC numerical simulation method. We use 
a rock mechanics test to determine the density, cohesion, and internal friction 
angle, elastic modulus, Poisson ratio, and tensile strength parameters. The 
test machine is the MTS815 Flex Test GT (Fig. 4). The samples of rock are 
obtained by drilling, where, for each specimen, Ф=50 mm with a height of 100 
mm. There are 12 experiments. The rocks used for 6 reference experiments are  



75A catastrophic landslide triggered debris flow in China’s Yigong: factors, dynamic processes, and tendency

air-dried granite rocks, and the rocks for the other experiments are water-
saturated granite rocks. The test results from the water-saturated granite rocks 
represent the actual landslide situation. The rock mass strength parameters of 
the BH01 and BH02 potential landslides are shown in Table 4. Because the F3 
fault passes directly through the BH01 potential landslide, the rock mass joint 
and fissures in the BH01 potential landslide are more developmental than in 
the BH02 potential landslide. The elastic modulus, Poisson ratios and tensile 
strengths for the BH01 and BH02 potential landslides have different values. We 
use the analogy method from engineering geology to estimate those parameters 
for the BH01 potential landslide, while the parameters for the BH02 potential 
landslide are from the rock mechanics tests.

′ = ′ = ( )c c RF RF/ , arctan /      (11)

ξ −ij i
l
j
j

j
l
i
l l

l
V

v n v n S= +





( ) ( ) ( )

=
∑1

6
1

4

  (12)

    (13)

    (14)

∆ ∆
ε −ij i

l
j
l l

i
l l

l

t
V

v n v n S= +





( ) ( ) ( )

=
∑6

1

4

  (15)

m
V

n S il
i
l l= 





=










( ) ( )1
9

1 3
2

max , ,    (16)

In equation 11-16, ′c  and ′  are the strength parameters after reduction,  
c and  are the strength parameters before reduction, and RF is the strength 
reduction coefficient. ij is the strain rate, vi

l  and v j
l  are the tetrahedral 

velocity, V is the volume of tetrahedron, S is the area of tetrahedron, ni
l( ) is the 

combined number of tetrahedrons in the element, ∆ij is the stress increment 

of tetrahedron,  is the stress correction term, Hij
*  is the incremental 

constitutive equation, ∆ij  is the strain rate correction term, ml is the quality of 
tetrahedrons.

The main controlling factors of the 2000 CLDF

Precipitation, temperature, and earthquakes

Based on the long-term earthquake, precipitation and temperature 
records, there is a spatiotemporal correlation between the disaster and an 
Ms 4.8 earthquake, the wet-dry cycle and the freeze-thaw cycle. To better 
observe the impacts of drought and the earthquake on the Yigong landslide, 
the processes of change in the EPA earthquake index and the SPI drought index 
were analyzed before the disaster using a proper time scale of fifteen years. 

  
Figure 3. (a) Photos of the BH01 and BH02 potential landslides. (b) Model profiles of the BH01 and BH02 potential landslides.

    
Fig. 4. Test equipment and the granite samples.

MTS

Origin Destroyed



76 Jun Li, Ningsheng Chen, Yuandi Zhao, Mei Liu, Weiyu Wang

The SPI of the Zhamunong Gully for every month between 1990 to 2004 is 
shown in Fig. 5a. Two months before the CLDF took place on April 9th, 2000, 
there was a small-magnitude dry-wet cycle in the Zhamunong Gully, with 
characteristics of a medium drought and slight moderate rainfall. From 1990 
to April 9, 2000, the wet-dry cycle often occurred. Over a short time-scale, the 
precipitation was lower in March, and the SPI was -1.41, which suggests that 
the weather was in a moderate drought. Precipitation of 62.6 mm in March 
2000 was significantly lower than the annual average precipitation of 87.3 
mm. From April 1th to 8th after the drought, the precipitation in the early stage 
reached 42.9 mm, accounting for 49% of the annual average precipitation. 
This indicates that Zhamunong Gully experienced a strong precipitation 
event before the disaster. At 8:00:09 on the night of April 9th, 2000, a Ms 4.8 
earthquake was recorded at the Linzhi station; the epicenter of this earthquake 
was 13 km away from the Zhamunong Gully. The seismic acceleration of 
the landslide in the Zhamunong Gully was 43.3 gal (Fig. 5a), equivalent to 
a seismic intensity of 5.5. Fissures in the rock masses are well developed in 
the source basin at elevations of 5250 m, and those rock masses are strongly 
influenced by the freeze-thaw cycle. The location of the Bomi meteorological 
station is N29°51.5’ and E94°46.1’, and the altitude is 2731 m. According to 
general meteorological principles, the temperature decreases by 0.6 degrees 
for every 100 m elevation increase. The temperature at 5250 m of elevation is 
estimated based on the temperature data of the Bomi meteorological station; 
the temperature results are shown in Fig. 5b. The largest seasonal temperature 
difference was 25°C, and the largest temperature difference before the disaster 
took place was 15°C. Moreover, the temperature shows a periodic change in 
the period from December-January with a low-temperature distribution and 
a periodic change in June-July with a high-temperature distribution, which 

illustrates that the impacts of seasonal freezing and thawing on the rock masses 
are very strong in the Zhamunong Gully.

Analysis of the main controlling factors

The structural characteristics of the rock masses are the basis for the 
formation of the 2000 CLDF. There are 3 sets of granite joints at the basin 
source. The southward-inclined joints with a tendency of 210 degrees coincide 
with the upstream slope of the basin source, providing an underground seepage 
channel for precipitation and snow meltwater. The freeze-thaw and dry-wet 
cycles have a great influence on the porosity compressive strength, elastic 
coefficient and shear strength of the rock mass. Freeze-thaw and dry-wet cycles 
accelerate the weathering of the rock mass, and more pores are generated in 
the granitic rock mass. When meltwater or rainfall enters into rock cracks, the 
water freezes into ice blocks and enlarges its volume. When the temperature 
drops below 0°C, the water entering the rock fissures will form ice, and the 
enlargement of the ice volume will force the crack to deepen and widen. When 
the temperature rises above 0°C, the ice melts in the rock mass cracks, and 
water flows into the new cracks, resulting in high pore water pressure in the 
rock mass, which reduces the shear strength of the rock mass. At 8:00:9.2 on 
April 9th, a Ms 4.8 earthquake occurred 13 km away from the Zhamunong 
Gully. The seismic acceleration in the basin source was 43.3 gal. Earthquakes 
have a topographic amplification effect on the source basin of the landslide. 
Based on investigations from local people, the water quality became black 
and the water quantity decreased significantly on April 8th in the Zhamunong 
Gully, which suggests that the main sliding surface and the steep cracks in the 
back edge of the sliding zone were fully penetrated, such that the rainwater and 

Table 4. Calculation parameters for the water-saturated granites in the BH01 and BH02 potential landslides.

Name Density /kg·m-3 Cohesion /MPa Internal friction angle/° Elastic modulus /GPa Poisson ratio Tensile strength /MPa

BH01 2630 9.69 58.27 3.0 0.31 3.5

BH02 2630 9.69 58.27 20 0.2 6

Original explanation Rock mechanics test, see Fig. 4

The elastic modulus, Poisson ratio and tensile strength of BH02 
are origin from the rock mechanics test. However, the rocks of 
BH01 are very fractured because the F3 fault crosses the middle 
of the BH01 zone. Therefore, we use the analogy method of 
Engineering geology used to estimate these parameters

  
Figure 5. (a) Change in the EPA and SPI in the Zhamunong Gully from 1990 to 2004. (b) The effect of the freeze-thaw cycle in Yigong from Jan. 1st, 1995 to Dec. 

31st, 2000. Modified from (Zhou et al., 2016).



77A catastrophic landslide triggered debris flow in China’s Yigong: factors, dynamic processes, and tendency

meltwater were completely penetrated into the main sliding surface of landslide 
and the rock masses of the sliding zone were saturated with water. Therefore, 
it is reasonable to suggest that a recent Ms 4.8 earthquake broke the locked-in 
section of the landslide.

The dynamic processes and characteristic parameters of the 2000 CLDF 
in the Zhamunong Gully 

Dynamic processes of the 2000 CLDF based on seismic waves

The strong seismic wave generated by the CLDF during its movement 
was recorded by the neighboring seismic stations (Dammeier et al., 2016). 
From 20:00 to 20:10 on April 9th, 2000, the Linzhi seismic station recorded the 
seismic wave generated by the 2000 CLDF in Yigong. Using the fast Fourier 
transform method to calculate the spectrum of the seismic wave generated by 
the 2000 CLDF, the largest acceleration of the seismic wave generated by the 
2000 CLDF in Yigong was 0.45 g, the largest seismic motion velocity was 
0.786 m·s-1, the main frequency value and the main power was 2 Hz, and 
the largest seismic motion amplitude was 64 cm. The spectrum of the Peak 
Ground Displacement (PGD) is properly used to divide the dynamic processes 
of the Yigong landslide after the following comparison of each seismic wave 
spectrum.

Based on the results of the seismic wave spectrum, the PGD spectrum of 
the seismic wave shown in Fig. 6 can better show the movement process of this 
landslide-debris flow. The amplitude at Point O begins to increase significantly, 
where Point O is the occurrence point of the 2000 CLDF. The time of Point O 
recorded by the Linzhi seismic station is 20:00:18.87 on April 9th, 2000, and 
the duration of the seismic wave’s transmission is 6.92 s, according to the 13 
km·s-1 in-ground seismic wave transmission rate. It is therefore inferred that the 
landslide time is 20:00:11.95. A debris flow moving at a high speed that strikes 
the bank of bending slope can produce a strong ground vibration phenomenon, 
which presents as a catastrophe point in the amplitude or acceleration of the 
seismic wave spectrum. There are 5 impact points during the movement 
of the 2000 CLDF in Yigong according to the graph of the seismic motion 
displacement and the remote sensing image. As Fig. 7 shows, the impact point 
A has an obvious impact mark, and it is the first impact point of the 2000 
CLDF. According to the motion mark of the 2000 CLDF, we can judge that 
point B is the impact point of the debris flow. The debris flow shows an obvious 
improvement at the impact points C, D, and E, which shows that the debris flow 
was hindered by three apparent places in the valley.

According to the seismic wave and based on the movement patterns of 
the 2000 CLDF, the four dynamic landslide processes are (1) joint and crack 
development in the landslide, (2) the process of crack fracture and sliding, 
(3) the landslide translation into a debris flow, and (4) debris flow movement 
and deposition. The dynamic processes of the latter three segments have clear 
surface vibration characteristics (Table 5). The dynamic process of O-A is 
joint and crack development in the landslide. The large amplitude and high-
frequency characteristics were revealed during the crack fracture and sliding 
process of the landslide, with a maximum amplitude and frequency of 48.35 
cm and 2.1 Hz, respectively. As debris flow energy increases, the amplitude is  
large, and the maximum amplitude of section B is 64 cm during the dynamic 
process of the landslide becoming a debris flow (A-B). Because the debris 
flow hit the mountain at the bend, the amplitude and frequency are high in 

the dynamic processes B-C of the debris flow movement, with a maximum 
amplitude of 42.64 cm and a frequency of 2.0 Hz. Because the bend in the 
channel is large during the dynamic processes D-E of debris flow movement, 
the amplitude of the wave increases to a maximum amplitude of 50 cm,  
but the frequency is reduced to 1.4 Hz. The debris flow was deposited gradually, 
and the impact of the debris flow on the ground gradually weakened after the 
mountain-pass section. Therefore, the amplitude of the wave decreases to 30 
cm and the frequency decreases to 1.0 Hz in the dynamic process of debris flow 
deposition.

Process of joint and crack development in the landslide

According to the terrain and wedge shape, the landslide elevation ranged 
between 4500 m and 5320 m. Before sliding, the landslide was one of the 
main peaks in the basin, covered by ice and snow year-round. After sliding, the  
bottom of the landslide appears as a “V”-type hanging gully. The sides of  
the landslide are steep and smooth. The angle of the gully slope is 40-50 degrees, 
the channel slope is 25 degrees, and the direction of channel trends to the SW. 
The trailing edge of the landslide is nearly a vertical cliff, and the granite rock 
mass is smooth. The NE-trending faults parallel to the lateral landslide wall 
are developed on both sides of the gully, and they form an “X”-type landslide 
foundation with good connectivity. During the process of the formation of the  
landslide, the joints and fissures in the granite are well developed due to  
the influence of regional tectonics in the Zhamunong Gully. There are three 
groups of large joints shown as follows (Fig. 8). The attitude of the No. 1 preferred 
structure plane (PSP) is 20334º, and the attitudes of the No. 2 PSP and No. 
3 PSP are 9457º and 21186º, respectively. Those joints fractured the rock 
mass of the landslide. In particular, the No. 3 PSP controlled the development of 
the steep cracks at the back of the landslide. The development of the slip surface 
was controlled by the No. 1 PSP. Under the influence of earthquakes and the 
freeze-thaw and dry-wet cycles, the joints develop and fracture only partially. 

Figure 6. Dynamic processes of the 2000 CLDF categorized by the peak 
ground displacement (PGD).

Table 5. Dynamic processes of the 2000 CLDF

Name of different dynamic processes Sections Duration/s Maximum amplitude/cm Maximum frequency/Hz

Crack fracture and sliding process O—A 9 48.35 2.1

Landslide transformation into debris flow A—B 10.25 64 2.1

Debris flow movement and deposition

B—C 8.75 42.64 2

C—D 14.5 32 2

D—E 40.25 50 1.4

After point E 247.25 30 1



78 Jun Li, Ningsheng Chen, Yuandi Zhao, Mei Liu, Weiyu Wang

   

   

  
Figure 7. a-e are the remote sensing images of impact points A-E of the 2000 CLDF; (f) is the landside trace image from start to end. The remote sensing images are 

from the time of February, 22th, 2015.

Impact Flow arrow of 
Impact 

B

Impact 

B

Impact 

B



79A catastrophic landslide triggered debris flow in China’s Yigong: factors, dynamic processes, and tendency

On April 8th, 2000, the amount of water decreased significantly and the water 
quality was significantly blackened in the Zhamunong Gully. The amount and 
color of the water demonstrate that the boundaries of the landslide bed (the two 
main sliding surfaces and the steep fractures of the trailing edge) were basically 
connected. The precipitation and snowmelt water had completely penetrated 
into the landslide bottom.

Figure 8. Distribution of joints and cracks in the landslide.

Crack fracture and sliding process

Length of the locking section of the crack

According to equation (1), when the length of the locking section L=455 
m (Table 6), the landslide is in a state of critical stability. When the trailing edge 

and front edge of landslide crack more, the length of the rock mass’s locking 
section L<455 m or the depth of the cracking segment in trailing edge Hcr >363 
m, the landslide will slide.

Crack fracture and sliding process

The frontal mound deposits were moved from the top of the basin source 
because only the top of the basin source had the granite rock masses. Those 
mound deposits had many ice-containing muds (Fig. 9a), suggesting that the 
granite rock masses were strongly influenced by the long-term freeze-thaw 
and dry-wet cycles. There are many cracks in the granite rock masses at the 
top of the basin. According to a rock mechanics test and the landslide stability 
calculation results, under the combined effect of many conditions, such as 
a quick cutting of the valley in the Yigong region, earthquakes, temperature 
changes, and continuous rainfall, a high-angle fissure in the trailing edge  
of landslide develops quickly and continuous creeping deformation occurs in 
the landslide along the weak structural plane or fracture surface, forming a mid 
‘locking section’. The locking section is a geological structure that has a high 
bearing capacity and stress concentration in the potential sliding surface of the 
slope. The natural locking segment usually has large-scale and flat geometry 
and bears extremely slow shear loading or stress corrosion. The continuous 
creeping deformation of the avalanche mass leads the rock mass to further 
decline in strength, including the high-angle fissure in Table 6, the trailing 
edge and the front slow-inclined fracture surface. The landslide is driven by a 
force toward the slope under the action of high pore-water pressure before the 
landslide is generated, which can be indicated by a strong rainfall process from 
April 1 to April 9 and the color of the water turned black and the water quantity 
decreased significantly on April 8. The residual locking section on the structure 
surface of the BH01 landslide was close to being sheared off by a huge thrust 
force and an uplift force, and the softening of water causes the main sliding 
surface. The final locking section of 455 m was eventually ruptured by the Ms 
4.8 earthquake, and then the landslide occurred (Fig. 9b).

Landslide translation into a debris flow, and the movement and deposition 
of the debris flow

Before sliding, the debris deposits were gradually saturated under the 
infiltration of snowmelt water and precipitation. The tremendous impact force 
from the landside impact on the gully wall occurred instantly. The bottom 

Table 6. Calculation of landslide stability

Stable state
Seismic force

/KN·m-1 Gravity  /KN·m-1 Fracture water 
pressure /KN·m-1

Sliding surface water 
pressure /KN·m-1

Sliding resistance force 
FK /KN·m-1

Slippage FS /
KN·m-1 L/m

Critical stability 4077881 15991690 164711 412755 12922659 12922659 455

   
Figure 9. (a) Mound deposit of the 2000 CLDF, (b) Model of sliding-tension-shearing failure.

Mound 



80 Jun Li, Ningsheng Chen, Yuandi Zhao, Mei Liu, Weiyu Wang

of the loose deposit liquefied, the shear strength of the landslide decreased, 
and the resistance of the landslide decreased due to liquefaction from the 
high-speed ring shear tests (Hu et al., 2015). Therefore, the landslide moved 
at a higher average speed of 120.98 m/s. The landslide material was mainly 
gravel and rock debris. When these high-density materials rushed out of the 
narrow gully into a wider gully, the landslide materials mixing with air were 
transformed into a debris flow, which moved at a high speed. The high-speed 
debris flow gradually silts away in the wide gully after it has rushed out of the 
mountain mouth.

Characteristic parameters of the dynamic processes

Density

We collected 4 particle samples of the 2000 CLDF in 2004, which were 
not influenced by precipitation. The distribution curve of the particle size of the 
4 samples was obtained by a sieving test. The densities of the 4 deposits are 
calculated using the equation given by (Li and Chen, 2018). An average density 
of 1.97 t·m-3 for the 2000 CLDF is calculated by averaging the densities of the 
different locations in Table 7.

Table 7. The density of the 2000 CLDF

No. Locations Clay particle content P0.005 Density γc/t·m
-3

1 Impact point C 0.05 2.01

2 Impact point D 0.05 1.98

3 Impact point E 0.06 2.04

4 Impact point F 0.03 1.88

Velocity

The average velocity of the 2000 CLDF is estimated based on the time 
interval of the seismic waves and the distance between each impact point (Table 
8). The average velocity of the 2000 CLDF is 30.12 m·s-1, the starting speed 
of the landslide in the O-A section is 89.89 m·s-1, and the average velocities 
of stages A-B, B-C, C-D, D-E, and E-F are 120.98, 108.57, 71.38, 53.14 and 
15.25 m·s-1, respectively. The average velocity calculated by the seismic wave 
is similar to the velocity process computed by the Massflow software (Fig. 10), 
indicating the seismic wave can be used to predict the dynamic parameters of 
similar CLDF.

Discharge

A two-dimensional mountainous mass flow dynamic procedure solver 
(Massflow-2D) is based on the theory of continuum mechanics of depth 

integration using the improved MacCormack TVD finite difference method. 
The Massflow software has a high-efficiency calculation, and it can simulate 
mountain disaster dynamics, it considers the complex topography with the 
characteristics of second-order accuracy and adaptive solution domain. 
Therefore, the flow process of the 2000 CLDF was simulated by the Massflow 
software (Ouyang et al., 2013, Ouyang et al., 2015). The discharge of the debris 
flow is 504×104 m3·s-1. The discharges at impact points E and F are 85.9×104 
m3·s-1 and 7.8×104 m3·s-1, respectively. The discharge processes of the 2000 
CLDF first increased and then decreased, and the maximum discharge of the 
2000 CLDF was 504×104 m3·s-1, which occurred at the second impact point 
B. The different discharge locations of the 2000 CLDF are shown in Table 9.

Table 9. Discharges of the 2000 CLDF

Locations A B E F

Discharges/×104 m3·s-1 325.5 504 85.9 6.2

The tendency for CLDFs in the Zhamunong Gully

Based on the detailed internal and external landslide investigation 
presented in the current study, a CLDF can be predicted in the Zhamunong 
Gully. The smaller debris flows occurring after the CLDF disaster will decrease 
year by year. (1) An analysis of historical disasters shows that there is a 
possibility of CLDF disasters recurring. As shown in Fig. 11a, the scale of the 
debris flow fluctuates in the Zhamunong Gully. The scale of debris flows from 
1902 and 2000 are 6.04×108 m3 and 3×108 m3, respectively. After two peaks, the 
scale of the disasters decreased year by year. The scale of debris-flow processes 
shows that a CLDF may occur in the future in the Zhamunong Gully. (2) The 
FLAC numerical simulation shows that plastic rock masses exist in the top of 
the basin; these are the material basis for the occurrence of CLDFs. Under a 
middle magnitude earthquake and extreme precipitation, the source rock masses 
undergo plastic deformation in the Zhamunong Gully, and the potential sliding 
surfaces of BH01 and BH02 are shown in Fig. 11b. The plastic rock masses 
show that the CDLF may happen again in the future. Therefore, we estimate 

Fig. 10. The simulated velocity of 2000 CLDF by the Massflow software

Table 8. The velocity of the 2000 CLDF

Stage O-A A-B B-C C-D D-E E-F O-F

Distance/m 809 1240 950 1035 2139 3770 9939

Time/s 9 10.25 8.75 14.5 40.25 247.25 330

Average velocity/m·s-1 89.89 120.98 108.57 71.38 53.14 15.25 30.12



81A catastrophic landslide triggered debris flow in China’s Yigong: factors, dynamic processes, and tendency

the average area of BH01 to be 111879.5 m2, and its width and volume are 
822.07 m and 0.92×108 m3, respectively. Similarly, the average area of BH02 is  
100314 m2, while the width of BH02 is 935.30 m and the volume of BH02  
is 0.94×108 m3. (3) Regional tectonics, earthquakes, and an extreme climate can 
activate CLDF disasters in the Zhamunong Gully. GPS measurements show that 
India and Southern Tibet converge at a rate of 20.3 mm/a, and approximately 
80% of the convergence is absorbed by a 50 km-wide deformation zone 
centered on the southern edge of the Tibetan Plateau (Larson et al., 1999). Under 
the intense compression of the Himalayan tectonic movement, large landslides 
have formed in the Yigong region. The Yigong region has a large number of 
faults. Frequent seismicity occurs in this region with a high seismic intensity. 
The rock masses continue to accumulate energy generated by earthquakes. 
Extreme climatic events occur frequently, and precipitation is abundant in 
the Yigong region. The maximum rainfall in one hour in the past four years is  
92.5 mm. In the past 60 years, the annual mean temperature has been increasing 
year by year, and the glacier in the source basin is gradually shrinking. In 
conclusion, the source of the rock masses can release significant elastic energy 
under earthquake and extreme climate conditions, and a large number of 
fragmented loose material sources slide along the steep terrain, thus forming 
a CLDF.

Conclusions

The conclusions contain three parts, which are stated as follows:

(1) The main controlling factors of the 2000 CLDF were the long-term 
freeze-thaw and dry-wet cycles and a middle magnitude earthquake. The impact 
of Ms 4.8 earthquake cannot be neglected for the occurrence of 2000 CLDF.

There is a coupled relationship between the occurrence of the 2000 CLDF, 
the earthquake, the freeze-thaw cycle, and the dry-wet cycle. From March to 
April 9th, 2000, a small-scale dry-wet cycle occurred in the Zhamunong Gully. 
The rock masses of BH01 landslide was saturated under the long-term freeze-
thaw and dry-wet cycle conditions. Therefore, the BH01 landslide occurred at 8 
pm and 11.95 seconds on 9th April 2000. A middle magnitude earthquake of Ms 
4.8 occurred approximately 13 km away from the Zhamunong Gully at 8 pm 
and 9.2 seconds on 9th April 2000. The top rock masses obtained 43.3 gals of 
seismic acceleration. Under the influence of the Ms 4.8 earthquake, the BH01 
landslide occurred.

(2) Based on the ground vibration spectrum recorded by the Linzhi 
seismic station, there were four dynamic processes of the 2000 CLDF, including 
the process of joint and crack development in the landslide, the crack fracture 
and sliding process, the process of landslide translation into a debris flow, the 
movement and deposition of the debris flow. The boundary and magnitude of 
the BH01 landslide were controlled by the joints in the granite rock masses. The 
landslide was saturated under the long-term freeze-thaw and dry-wet cycles 
before the disaster. The crack fracture and slide process of the 2000 CLDF was 

revealed by a ‘creep-tensile-shear’ failure model. The attenuation of seismic 
activity and the strength of the granite rock mass led to the landslide occurring 
along cracks. The Ms 4.8 earthquake may have ruptured the final 455 m locking 
sections, and then the landslide occurred. The density of the 2000 CLDF was 
2.0 t·m-3, the starting velocity was 89.89 m·s-1, the average velocity was 30.12 
m·s-1, and the discharge shape of the 2000 CLDF first increased and then 
decreased. The maximum discharge of the 2000 CLDF was 504×104 m3·s-1, 
which occurred in the second impact section.

(3) A CLDF may occur in the Zhamunong Gully in the future. The smaller 
debris flows occurring after the CLDF will decrease year by year.

Acknowledgment

The study was supported by the programs of National Natural Science 
Foundation of China (Grant Nos. 41807075, 41671112 and 41861134008), and 
the talent introduction project of Sichuan University of Science & Engineering 
(Grant Nos. 2018RCL09), and the student’s innovation and entrepreneurship 
training program of Sichuan University of Science & Engineering (B50104124), 
and the opening project of Sichuan Province University Key Laboratory of 
Bridge Non-destruction Detecting and Engineering Computing (Grant Nos. 
2019QZJ01), and the projects of Zigong Bureau of Science and Technology 
(Grant Nos. 2019CXMZ08 and 2019YYJC30).

References

Chen, N. S., Li, J., Liu, L. H., Yang, C. L. & Liu, M. (2018). Post-earthquake 
denudation and its impacts on ancient civilizations in the Chengdu 
Longmenshan region, China. Geomorphology, 309, 51-59.

Chen, N. S., Tanoli, J. I., Hu, G. S., Wang, F. N., Yang, C. L., Ding, H. T., He, 
N. & Wang, T. (2016). Outlining a stepwise, multi-parameter debris 
flow monitoring and warning system: an example of application in 
Aizi Valley, China. Journal of Mountain Science, 13(9), 1527-1543.

Chen, N. S., Yang, L., Zhou, H. B., Deng, M. F., & Han D. (2014). Combined 
Impacts of Antecedent Earthquakes and Droughts on Disastrous 
Debris Flows. Journal of Mountain Science, 11(6),1507-1520.

Chen, N. S., Zhou, W., Yang, C. L., Hu, G. S., Gao, Y. C. & Han, D. (2010). 
The processes and mechanism of failure and debris flow initiation for 
gravel soil with different clay content. Geomorphology, 121(3–4), 
222-230.

Dammeier, F., Moore, J. R., Hammer, C., Haslinger, F., & Loew, S. (2016). 
Automatic detection of alpine rockslides in continuous seismic data 
using Hidden Markov Models. Journal of Geophysical Research 
Earth Surface, 121(2), 351-371.

    
Figure 11. (a) Debris flow change processes from 1902 to 2015. (b) Stability simulation results of the BH01 and BH02 potential landslides.



82 Jun Li, Ningsheng Chen, Yuandi Zhao, Mei Liu, Weiyu Wang

Delaney, K. B. & Evans, S. G. (2015). The 2000 Yigong landslide (Tibetan 
Plateau), rockslide-dammed lake and outburst flood: Review, 
remote sensing analysis, and process modelling. Geomorphology, 
246, 377-393.

Delgado, J., Garrido, J., López-Casado, C., Martino, S., & Peláez J. A. (2011) 
On far field occurrence of seismically induced landslides. Engineering 
Geology, 123(3), 204-213.

Deng, M. F., Chen, N. S., & Liu, M. (2017). Meteorological factors driving 
glacial till variation and the associated periglacial debris flows in 
Tianmo Valley, south-eastern Tibetan Plateau. Natural Hazards & 
Earth Systemences, 17(3), 345-356.

Evans, S. G. & Delaney, K. B. (2011). Characterization of the 2000 Yigong 
Zangbo River (Tibet) Landslide Dam and Impoundment by Remote 
Sensing. Lecture Notes in Earth Sciences, 133, 543-559.

Guzzetti, F., Ardizzone, F., Cardinali, M., Rossi, M. & Valigi, D. (2009). 
Landslide volumes and landslide mobilization rates in Umbria, central 
Italy. Earth & Planetary Science Letters, 279(3–4), 222-229.

Hu, M. J., Pan, H. L., Zhu, C. Q. & Wang, F. W. (2015). High-speed ring shear 
tests to study the motion and acceleration processes of the Yigong 
landslide. Journal of Mountain Science, 12(6), 1534-1541.

Huang, R. Q, Chen, G. Q., Guo, F., Zhang, G. & Zhang, Y. (2016). Experimental 
study on the brittle failure of the locking section in a large-scale rock 
slide. Landslides, 13(3), 583-588.

Huang, R. Q. & Fan, X. X. (2013). The landslide story. Nature Geoscience, 
6(5), 325-326.

Jing, F. U., Xiu-Li, D., Cong-Lie, Z. & Xuan, Z. (2008). Application of 
Lagrangian difference method based on shear strength reduction (in 
Chinese). Journal of Yangtze River Scientific Research Institute, 25(2), 
58-58. 

Kang, C., Chan, D., Su, F. H. & Cui, P. (2017). Runout and entrainment analysis 
of an extremely large rock avalanche—a case study of Yigong, Tibet, 
China. Landslides, 14(1), 123-139.

Larson, K. M., Bürgmannj, R., Bilham, R. & Freymueller, J. T. (1999). Kinematics 
of the India-Eurasia collision zone from GPS measurements. Journal 
of Geophysical Research Solid Earth, 104(B1), 1077-1093.

Lee, H. Y., Chung, S. L., Wang, J. R., Wen, D. J., Lo, C. H. & Yang, T. F. 
(2003). Miocene Jiali faulting and its implications for Tibetan tectonic 
evolution. Earth and Planetary Science Letters, 205(3-4), 185-194.

Li, J., Chen, N. S., Javed, I., & Han, D. (2018). The model for dilution process 
of landslide triggered debris flow —a case of Guanba river in Tibet 
southeastern plateau. Earth Sciences Research Journal, 22(2), 103-111.

Liu, N. (2000). On emergency treatment scheme for Yigong massive landslide 
and river blockage disaster in Tibet (in Chinese). Yangtze River, 31(9), 
10-12. 

Liu, W. & He, S. M. (2018). Dynamic simulation of a mountain disaster chain: 
landslides, barrier lakes, and outburst floods. Natural Hazards, 90(2), 
757-775.

Lu, J. T. (2002). A Tentative Discussion on the Monitoring of the Yigong 
Landslide-blocked Lake with Satellite Remote Sensing Technique. 
Acta Geosicientia Sinica, 23(4), 363-368.

Mccubbine, J. C., Featherstone, W. E. & Kirby, J. F. (2017). Fast-Fourier-based 
error propagation for the gravimetric terrain correction. Geophysics, 
82(4), G71-G76.

Ouyang, C. J., He, S. M., & Tang, C. (2015). Numerical analysis of dynamics of 
debris flow over erodible beds in Wenchuan earthquake-induced area. 
Engineering Geology, 194, 62-72.

Ouyang, C. J., He, S. M., Xu, Q., Luo, Y. & Zhang, W. (2013). A MacCormack-
TVD finite difference method to simulate the mass flow in 
mountainous terrain with variable computational domain. Computers 
& Geosciences, 52(1), 1-10.

Samodra, G., Hadmoko, D. S., Wicaksono, G. N., Adi, I. P., Yudinugroho, 
M., & Wibowo, S. B. (2018). The March 25 and 29, 2016 landslide-
induced debris flow at Clapar, Banjarnegara, Central Java. Landslides, 
15(5), 985-993.

Schmidt, J. L., Zeitler, P. K., Pazzaglia, F. J., Marissa, M. T., David, L. S. 
& Matthew F. (2015). Knickpoint evolution on the Yarlung river: 
Evidence for late Cenozoic uplift of the southeastern Tibetan plateau 
margin. Earth & Planetary Science Letters, 430, 448-457.

Shang, Y. J., Yang, Z. F., Li, L. H., Liu, D. & Wang, Y. (2003). A super-large 
landslide in Tibet in 2000: background, occurrence, disaster, and 
origin. Geomorphology, 54(3–4), 225-243.

Song J., Tang F., Deng Z., Xiao G. and Chen, W. (2013). Late Quaternary 
Movement Characteristic of Jiali Fault in Tibetan Plateau (in 
Chinese). Acta Scientiarum Naturalium Universitatis Pekinensis, 
49(6), 973-980. 

Tewari, P. (2004). A Study on Soil Erosion in Pasighat Town (Arunachal 
Pradesh) India. Natural Hazards, 32(2), 257-275.

Wang, G. H. & Sassa, K. (2003). Pore-pressure generation and movement 
of rainfall-induced landslides: effects of grain size and fine-particle 
content. Engineering Geology, 69(1–2), 109-125.

Wang, L., Chen, Z. Y., Wang, N. X., Sun, P., Yu, S., & Li, S. (2016). Modeling 
lateral enlargement in dam breaches using slope stability analysis 
based on circular slip mode. Engineering Geology, 209, 70-81.

Wang, S. Y. & Shi, Z. L. (1993). The relationship between the sensible radius 
and magnitude of earthquakes and its application: The symposium on 
Chinese seismic zonation (in Chinese). Beijing Seismological Press, 
Beijing, China, 89-96 pp. 

Wang, T., Chen, X. Q., Li, K., Chen, J. & You, Y. (2018a). Experimental study 
of viscous debris flow characteristics in drainage channel with oblique 
symmetrical sills. Engineering Geology, 233, 55-62.

Wang, T., Chen, J. G., Chen, X. Q., You, Y., & Cheng, N. S. (2018b). Application 
of incomplete similarity theory to the estimation of the mean velocity 
of debris flows. Landslides, 15, 2083-2091.

Wang, X. L. & Li, J. C. (2017). A new solver for granular avalanche simulation: 
Indoor experiment verification and field scale case study. Science 
China (Physics, Mechanics & Astronomy), 60(12), 124712.

Wang, Z. H. & Lu, J. T. (2002). Satellite monitoring of the Yigong landslide in 
Tibet, China. Proceedings of 

SPIE-The International Society for Optical Engineering, 4814, 34-38.
Xu, Q., Shang, Y. J., Aschtheo, V., Wang, S. T., Zhang, Z. Y. & Dong, X. J. 

(2012). Observations from the large, rapid Yigong rock slide – debris 
avalanch. Revue Canadienne De Géotechnique, 49(5), 589-606.

Yu, Y. X. & Gao, M. T. (2001). Effects of the hanging wall and footwall on peak 
acceleration during the Chi-Chi Earthquake, Taiwan (In Chinese). Acta 
Seismologica Sinica, 23(6), 615-621.

Zhou, J. W., Cui, P., & Hao, M. H. (2016). Comprehensive analyses of the 
initiation and entrainment processes of the 2000 Yigong catastrophic 
landslide in Tibet, China. Landslides, 13(1), 39-54.

https://www.sciencedirect.com/science/article/pii/S0012821X15005683#!
https://www.sciencedirect.com/science/article/pii/S0012821X15005683#!
https://www.sciencedirect.com/science/article/pii/S0012821X15005683#!