An assessment of Cikangkareng rockfall due to the Tasikmalaya earthquake on September 2, 2009

According to Hunt [1], landslides involve very complex phenomena and mechanisms. They could be small to very large scale, such as those burying cities or villages. Several earthquake rockfall have been reported worldwide. Tsao-Ling landslide [2,3], the Chiufengershan landslide [4], and the Las Colinas landslide during the 2001 El Salvador Earthquake [5] Rockfall was triggered by the earthquake that shook Tasikmalaya 2009, reaching 7.3 on the Richter scale at 14.55 to this earthquake event, the rockfall phenomena caused damage and fatalities in Cikangkareng village District Cianjur city, West Java. Based on information from the National Bureau for D (BNPB), until 13 September 2009, the casualties reached 81 people and 45 people were missing likely that the missing people were buried by rockfall materials. The rockfall 1,500,000 m the Cikangkareng rockfall which consisted of many large rocks. Fig. 2 shows the location of the Cikangkareng rockfall. As seen in the figure, vulnerability to land movement. According to the Bureau


Introduction
According to Hunt [1], landslides involve very complex phenomena and mechanisms. They could be small to very large scale, such as those burying cities or villages. Several earthquake rockfall have been reported worldwide. Tsao-Ling landslide [2,3], the Chiufengershan landslide [4], and the Las Colinas landslide during the 2001 El Salvador Earthquake [5] Rockfall was triggered by the earthquake that shook Tasikmalaya 2009, reaching 7.3 on the Richter scale at 14.55 to this earthquake event, the rockfall phenomena caused damage and fatalities in Cikangkareng village District -Cianjur city, West Java. Based on information from the National Bureau for D (BNPB), until 13 September 2009, the casualties reached 81 people and 45 people were missing likely that the missing people were buried by rockfall materials. The rockfall 1,500,000 m 3 the Cikangkareng rockfall which consisted of many large rocks. Fig. 2 shows the location of the Cikangkareng rockfall. As seen in the figure, vulnerability to land movement. According to the Bureau Introduction According to Hunt [1], landslides involve very complex phenomena and mechanisms. They could be small to very large scale, such as those burying cities or villages. Several earthquake-induced instances of landslide or rockfall have been reported worldwide.
Ling landslide [2,3], the Chiufengershan landslide [4], and the Las Colinas landslide during the 2001 El vador Earthquake [5]. Rockfall was triggered by the earthquake that shook Tasikmalaya -West Java on Wednesday, 2 September 09, reaching 7.3 on the Richter scale at 14.55 to this earthquake event, the rockfall phenomena caused damage and fatalities in Cikangkareng village Cianjur city, West Java. Based on information from the National Bureau for D (BNPB), until 13 September 2009, the casualties reached 81 people and 45 people were missing likely that the missing people were buried by rockfall materials. The rockfall estimated has a volume of about 3 , as shown in the Cikangkareng rockfall which consisted of many large 2 shows the location of the Cikangkareng As seen in the figure, vulnerability to land movement. According to the Bureau unopargeo@yahoo.com assessment of Cikangkareng earthquake on September 2, 2009 and Lim Aswin Civil Engineering Department, Parahyangan Catholic The earthquake that shook Tasikmalaya amounting to 7.3 on the Richter scale at 02.55 pm was one of the geological natural disasters that affected angkareng village -Cibinong District, Cianjur, West Java Meteorology and Geophysics (BMG), Among 30 districts in Cianjur, 15 districts have great potential for land movement. The topographic condition is a fairly st . In addition, a residential area was located at the foot of the hill. Thus, the geological conditions are fragile. Based on the map of land movement vulnerability (DVMBG, 2004), the Cianjur area is as a zone of high movement potential of soil which means that movement of soil is easily triggered by rainfall and earthquakes. The Tasikmalaya earthquake event triggered a landslide on a large scale and caused rockfall. The material of the sit sandstone, breccias, sandy tuffs, and yellow spots. The mineral testing results revealed that the existing minerals are Feldspar and Cristobalite. From the result of the slake durability. The main cause is not only the acceleration in the horizontal or vertical direction of the rocks but also the seismic force can cause an increase in the water pressure in the pores and the rock fracture can give f pressure in the contact field of rock joint. As a result of this, the earthquake event triggered an avalanche on a large scale and caused rockfall. Due to the contact stress decreasing drastically, practically, he friction resistance of the joint According to Hunt [1], landslides involve very complex phenomena and mechanisms. They could be small to very large scale, such as those burying cities or villages. induced instances of landslide or rockfall have been reported worldwide.
Ling landslide [2,3], the Chiufengershan landslide [4], and the Las Colinas landslide during the 2001 El Rockfall was triggered by the earthquake that shook West Java on Wednesday, 2 September 09, reaching 7.3 on the Richter scale at 14.55 to this earthquake event, the rockfall phenomena caused damage and fatalities in Cikangkareng village Cianjur city, West Java. Based on information from the National Bureau for Disaster Prevention (BNPB), until 13 September 2009, the casualties reached 81 people and 45 people were missing likely that the missing people were buried by rockfall estimated has a volume of about shown in Fig. 2. This picture illustrates the Cikangkareng rockfall which consisted of many large 2 shows the location of the Cikangkareng As seen in the figure, Cianjur vulnerability to land movement. According to the Bureau pargeo@yahoo.com

Cikangkareng September 2, 2009
Aswin 1 Parahyangan Catholic University The earthquake that shook Tasikmalaya amounting to 7.3 on the Richter scale at 02.55 pm was one of the geological natural disasters that affected Cibinong District, Cianjur, West Java Meteorology and Geophysics (BMG), Among 30 districts in Cianjur, 15 districts have great potential for land movement. The topographic condition is a fairly st . In addition, a residential area was located at the foot of the hill. Thus, the geological conditions are fragile. Based on the map of land movement vulnerability (DVMBG, 2004), the Cianjur area is as a zone of high movement potential of soil which means that movement of soil is easily triggered by rainfall and earthquakes. The Tasikmalaya earthquake event triggered a landslide on a large scale and caused rockfall. The material of the site collapse consists mainly of sedimentary rocks, sandstone rocks, sandstone, breccias, sandy tuffs, and yellow spots. The mineral testing results revealed that the existing minerals are Feldspar and Cristobalite. From the result of the slake durability. The main cause is not only the acceleration in the horizontal or vertical direction of the rocks but also the seismic force can cause an increase in the water pressure in the pores and the rock fracture can give f pressure in the contact field of rock joint. As a result of this, the earthquake event triggered an avalanche on a large scale and caused rockfall. Due to the contact stress decreasing drastically, practically, he friction resistance of the joint plane could be significantly reduced. The earthquake that shook Tasikmalayaamounting to 7.3 on the Richter scale at 02.55 pm was one of the geological natural disasters that affected Cibinong District, Cianjur, West Java Meteorology and Geophysics (BMG), Among 30 districts in Cianjur, 15 districts have great potential for land movement. The topographic condition is a fairly steep slope of hills with an almost upright angle ± 80 . In addition, a residential area was located at the foot of the hill. Thus, the geological conditions are fragile. Based on the map of land movement vulnerability (DVMBG, 2004), the Cianjur area is as a zone of high movement potential of soil which means that movement of soil is easily triggered by rainfall and earthquakes. The Tasikmalaya earthquake event triggered a landslide on a large scale and e collapse consists mainly of sedimentary rocks, sandstone rocks, sandstone, breccias, sandy tuffs, and yellow spots. The mineral testing results revealed that the existing minerals are Feldspar and Cristobalite. From the result of the slake durability. The main cause is not only the acceleration in the horizontal or vertical direction of the rocks but also the seismic force can cause an increase in the water pressure in the pores and the rock fracture can give f pressure in the contact field of rock joint. As a result of this, the earthquake event triggered an avalanche on a large scale and caused rockfall. Due to the contact stress decreasing drastically, practically, plane could be significantly reduced.
According  West Java on Wednesday, September 2, 2009, amounting to 7.3 on the Richter scale at 02.55 pm was one of the geological natural disasters that affected Cibinong District, Cianjur, West Java -Indonesia. According to the Bureau of Meteorology and Geophysics (BMG), Among 30 districts in Cianjur, 15 districts have great potential for eep slope of hills with an almost upright angle ± 80 . In addition, a residential area was located at the foot of the hill. Thus, the geological conditions are fragile. Based on the map of land movement vulnerability (DVMBG, 2004), the Cianjur area is as a zone of high movement potential of soil which means that movement of soil is easily triggered by rainfall and earthquakes. The Tasikmalaya earthquake event triggered a landslide on a large scale and e collapse consists mainly of sedimentary rocks, sandstone rocks, sandstone, breccias, sandy tuffs, and yellow spots. The mineral testing results revealed that the existing minerals are Feldspar and Cristobalite. From the result of the slake-durability, th durability. The main cause is not only the acceleration in the horizontal or vertical direction of the rocks but also the seismic force can cause an increase in the water pressure in the pores and the rock fracture can give f pressure in the contact field of rock joint. As a result of this, the earthquake event triggered an avalanche on a large scale and caused rockfall. Due to the contact stress decreasing drastically, practically, plane could be significantly reduced.
of Meteorology and Geophysics (BMG), out of 30 districts in Cianjur Regency, 15 have a great potential for land movement. The conditions of the topographic area are as follows: (1). The slope inclination is around 80 conditions are very fragile where a landslide or rockfall could easily be triggered by earthquakes or heavy rainfall events. Indonesia. According to the Bureau of Meteorology and Geophysics (BMG), Among 30 districts in Cianjur, 15 districts have great potential for eep slope of hills with an almost upright angle ± 80 . In addition, a residential area was located at the foot of the hill. Thus, the geological conditions are fragile. Based on the map of land movement vulnerability (DVMBG, 2004), the Cianjur area is as a zone of high movement potential of soil which means that movement of soil is easily triggered by rainfall and earthquakes. The Tasikmalaya earthquake event triggered a landslide on a large scale and e collapse consists mainly of sedimentary rocks, sandstone rocks, sandstone, breccias, sandy tuffs, and yellow spots. The mineral testing results revealed that the existing durability, the material has medium durability. The main cause is not only the acceleration in the horizontal or vertical direction of the rocks but also the seismic force can cause an increase in the water pressure in the pores and the rock fracture can give f pressure in the contact field of rock joint. As a result of this, the earthquake event triggered an avalanche on a large scale and caused rockfall. Due to the contact stress decreasing drastically, practically, of Meteorology and Geophysics (BMG), out of 30 districts in Cianjur Regency, 15 have a great potential for land movement. The conditions of the topographic area are as follows: (1). The slope inclination is around 80 o -90 conditions are very fragile where a landslide or rockfall could easily be triggered by earthquakes or heavy Debris materials consisting A previous land movement disaster was also recorded in 1980 at Cikangkareng, Cibeber, and Sukanegara, where the landslides were triggered by heavy rainfall. The landslide affected ± 200 m in the rockfall due to the Tasikmalaya , Jl. Ciumbuleuit 94, Bandung, Indonesia West Java on Wednesday, September 2, 2009, amounting to 7.3 on the Richter scale at 02.55 pm was one of the geological natural disasters that affected Indonesia. According to the Bureau of Meteorology and Geophysics (BMG), Among 30 districts in Cianjur, 15 districts have great potential for eep slope of hills with an almost upright angle ± 80 . In addition, a residential area was located at the foot of the hill. Thus, the geological conditions are fragile. Based on the map of land movement vulnerability (DVMBG, 2004), the Cianjur area is categorized as a zone of high movement potential of soil which means that movement of soil is easily triggered by rainfall and earthquakes. The Tasikmalaya earthquake event triggered a landslide on a large scale and e collapse consists mainly of sedimentary rocks, sandstone rocks, sandstone, breccias, sandy tuffs, and yellow spots. The mineral testing results revealed that the existing e material has medium durability. The main cause is not only the acceleration in the horizontal or vertical direction of the rocks but also the seismic force can cause an increase in the water pressure in the pores and the rock fracture can give f pressure in the contact field of rock joint. As a result of this, the earthquake event triggered an avalanche on a large scale and caused rockfall. Due to the contact stress decreasing drastically, practically, of Meteorology and Geophysics (BMG), out of 30 districts in Cianjur Regency, 15 have a great potential for land movement. The conditions of the topographic area are as follows: (1). The slopes are very steep, as their 90 o , (2). The geological conditions are very fragile where a landslide or rockfall could easily be triggered by earthquakes or heavy Debris materials consisting of large rocks A previous land movement disaster was also recorded in 1980 at Cikangkareng, Cibeber, and Sukanegara, where the landslides were triggered by heavy rainfall. The landslide affected ± 200 m in the Tasikmalaya West Java on Wednesday, September 2, 2009, amounting to 7.3 on the Richter scale at 02.55 pm was one of the geological natural disasters that affected Indonesia. According to the Bureau of Meteorology and Geophysics (BMG), Among 30 districts in Cianjur, 15 districts have great potential for eep slope of hills with an almost upright angle ± 80 -. In addition, a residential area was located at the foot of the hill. Thus, the geological conditions are categorized as a zone of high movement potential of soil which means that movement of soil is easily triggered by rainfall and earthquakes. The Tasikmalaya earthquake event triggered a landslide on a large scale and e collapse consists mainly of sedimentary rocks, sandstone rocks, sandstone, breccias, sandy tuffs, and yellow spots. The mineral testing results revealed that the existing e material has medium durability. The main cause is not only the acceleration in the horizontal or vertical direction of the rocks but also the seismic force can cause an increase in the water pressure in the pores and the rock fracture can give f pressure in the contact field of rock joint. As a result of this, the earthquake event triggered an avalanche on a large scale and caused rockfall. Due to the contact stress decreasing drastically, practically,

Tectonic
Some factors were suspected to have caused natural disasters due to the movement of tectonic plates. The movement of those plates is relatively slow but they move continuously and could cause a disaster. Indonesia is located between three tectonic plates, Indo-Australian plate, the Eurasian plate, and the Pacific plate, as shown in to move as much as 6 side and collate subduction downward

Tectonic formation
Some factors were suspected to have caused natural disasters due to the movement of tectonic plates. The movement of those plates is relatively slow but they move continuously and could cause a disaster. Indonesia is located between three tectonic plates, Australian plate, the Eurasian plate, and the Pacific plate, as shown in Fig. 3

Formation of
Geological conditions are very important because the earthquake vibration is propagated through the sub until it reaches the ground surface during the earthquake and this vibration could induce landslides or rockfall. Thus, it is very important to inv conditions in order to evaluate the risk of landslides.
Based on the geological map of West Java, as shown in Fig.  Holocene an active volcanic tuff, loose lava sediment which generally takes the form of andesite and basalt. The sources of Qv are Galunggung mountain and Talagabodas mountain.
As shown in Koloberes (Tmk sedimentary rocks with sand, crystal tuff, breccias with a parallel coating and is less massive. The rocks have been clogged with the weathering soil, such as and the colo due to the long drought, the crack is also observed on the ground. [7], the disaster area is located in a high potential ground movement zone. This means that the land movement is easily trigg earthquake. the sedimentary collapsed and the material slid into the residential area.

Formation of
Geological conditions are very important because the earthquake vibration is propagated through the sub until it reaches the ground surface during the earthquake and this vibration could induce landslides or rockfall. Thus, it is very important to inv conditions in order to evaluate the risk of landslides.
Based on the geological map of West Java, as shown Fig. 4, the southern part of West Java is dominated by olocene volcano rock (Qv). This rock is formed from an active volcanic tuff, loose lava sediment which generally takes the form of andesite and basalt. The sources of Qv are Galunggung mountain and Talagabodas mountain.
As shown in Fig.  Koloberes (Tmk) rock formation, which is composed of sedimentary rocks with sand, crystal tuff, breccias with a parallel coating and is less massive. The rocks have been clogged with the weathering soil, such as and the color is brownish or reddish due to the long drought, the crack is also observed on the ground.
Based on the Cianjur Area Vulnerability Zone Map [7], the disaster area is located in a high potential ground movement zone. This means that the land movement is easily trigg earthquake. With the sedimentary collapsed and the material slid into the residential area.

Formation of geology
Geological conditions are very important because the earthquake vibration is propagated through the sub until it reaches the ground surface during the earthquake and this vibration could induce landslides or rockfall. Thus, it is very important to inv conditions in order to evaluate the risk of landslides.
Based on the geological map of West Java, as shown 4, the southern part of West Java is dominated by volcano rock (Qv). This rock is formed from an active volcanic sediment consisting of lava, breccias, tuff, loose lava sediment which generally takes the form of andesite and basalt. The sources of Qv are Galunggung mountain and Talagabodas mountain. Fig. 5, the disaster area is composed of ) rock formation, which is composed of sedimentary rocks with sand, crystal tuff, breccias with a parallel coating and is less massive. The rocks have been clogged with the weathering soil, such as r is brownish or reddish due to the long drought, the crack is also observed on the Based on the Cianjur Area Vulnerability Zone Map [7], the disaster area is located in a high potential ground movement zone. This means that the land movement is easily triggered With the earthquake the sedimentary rocks clogged with the weathering collapsed and the material slid into the residential area. Geological conditions are very important because the earthquake vibration is propagated through the sub until it reaches the ground surface during the earthquake and this vibration could induce landslides or rockfall. Thus, it is very important to investigate geological conditions in order to evaluate the risk of landslides. Based on the geological map of West Java, as shown 4, the southern part of West Java is dominated by volcano rock (Qv). This rock is formed from sediment consisting of lava, breccias, tuff, loose lava sediment which generally takes the form of andesite and basalt. The sources of Qv are Galunggung mountain and Talagabodas mountain. 5, the disaster area is composed of ) rock formation, which is composed of sedimentary rocks with sand, crystal tuff, breccias with a parallel coating and is less massive. The rocks have been clogged with the weathering soil, such as r is brownish or reddish-brown. due to the long drought, the crack is also observed on the Based on the Cianjur Area Vulnerability Zone Map [7], the disaster area is located in a high potential ground movement zone. This means that the land ered by high rainfall or the earthquake magnitude of clogged with the weathering collapsed and the material slid into the residential area.
geology of rockfall area [6] Geological conditions are very important because the earthquake vibration is propagated through the sub-soil until it reaches the ground surface during the earthquake and this vibration could induce landslides or rockfall. estigate geological conditions in order to evaluate the risk of landslides.
Based on the geological map of West Java, as shown 4, the southern part of West Java is dominated by volcano rock (Qv). This rock is formed from sediment consisting of lava, breccias, tuff, loose lava sediment which generally takes the form of andesite and basalt. The sources of Qv are Galunggung mountain and Talagabodas mountain. 5, the disaster area is composed of ) rock formation, which is composed of sedimentary rocks with sand, crystal tuff, breccias with a parallel coating and is less massive. The rocks have been clogged with the weathering soil, such as silt and clay, brown. In addition, due to the long drought, the crack is also observed on the Based on the Cianjur Area Vulnerability Zone Map [7], the disaster area is located in a high potential ground movement zone. This means that the land by high rainfall or magnitude of 7.3 SR, clogged with the weathering collapsed and the material slid into the residential area.
Geological conditions are very important because the soil until it reaches the ground surface during the earthquake and this vibration could induce landslides or rockfall. estigate geological Based on the geological map of West Java, as shown 4, the southern part of West Java is dominated by volcano rock (Qv). This rock is formed from sediment consisting of lava, breccias, tuff, loose lava sediment which generally takes the form of andesite and basalt. The sources of Qv are 5, the disaster area is composed of ) rock formation, which is composed of sedimentary rocks with sand, crystal tuff, breccias with a parallel coating and is less massive. The rocks have been clay, In addition, due to the long drought, the crack is also observed on the Based on the Cianjur Area Vulnerability Zone Map [7], the disaster area is located in a high potential ground movement zone. This means that the land by high rainfall or 7.3 SR, clogged with the weathering The large areas under the crown of old rockfall and the landslide were triggered by heavy rainfall.  (Kompas,Sept 4 The topography at the disaster site has a slope with an inclination of almost 80 Babakan Caringin around 5 o -15 at Cikangkareng are categorized as rockfall. Some debris material has also been found in this event ( large earthquake force in the horizontal and vertic direction causes an increase of porewater pressure and inside the fractured rock. As a consequence, the friction resistance in the joint plane is significantly should be noted that the stability of rock slopes is influenced by several factor joint roughness, width and spacing of joint, fill material in the joints, and the existence of water

Location of rockfall
Satellite image of rockfall The large areas under the crown of old rockfall and the landslide were triggered by heavy rainfall. rockfall at Cikangkareng Evacuation after rockfall without heavy equipment Kompas, Sept 4 th , 2009) The topography at the disaster site has a slope with an inclination of almost 80 o Babakan Caringin village whose ground inclination is 15 o . (Figs. 6 and at Cikangkareng are categorized as rockfall. Some debris material has also been found in this event ( large earthquake force in the horizontal and vertic direction causes an increase of porewater pressure and inside the fractured rock. As a consequence, the friction resistance in the joint plane is significantly should be noted that the stability of rock slopes is influenced by several factor joint roughness, width and spacing of joint, fill material in the joints, and the existence of water The topography at the disaster site has a slope with an o -90 o . Below the cliff, there is village whose ground inclination is and 7). Land movement disasters at Cikangkareng are categorized as rockfall. Some debris material has also been found in this event ( large earthquake force in the horizontal and vertic direction causes an increase of porewater pressure and inside the fractured rock. As a consequence, the friction resistance in the joint plane is significantly should be noted that the stability of rock slopes is influenced by several factors such as joint orientation, joint roughness, width and spacing of joint, fill material in the joints, and the existence of water. The topography at the disaster site has a slope with an . Below the cliff, there is village whose ground inclination is 7). Land movement disasters at Cikangkareng are categorized as rockfall. Some debris material has also been found in this event (Fig. 8). A large earthquake force in the horizontal and vertic direction causes an increase of porewater pressure and inside the fractured rock. As a consequence, the friction resistance in the joint plane is significantly reduced. should be noted that the stability of rock slopes is s such as joint orientation, joint roughness, width and spacing of joint, fill material . The large areas under the crown of old rockfall and the The topography at the disaster site has a slope with an . Below the cliff, there is village whose ground inclination is 7). Land movement disasters at Cikangkareng are categorized as rockfall. Some debris 8). A large earthquake force in the horizontal and vertical direction causes an increase of porewater pressure and inside the fractured rock. As a consequence, the friction reduced. It should be noted that the stability of rock slopes is s such as joint orientation, joint roughness, width and spacing of joint, fill material

Specification
Types of debris material consist of sedimentary rocks, such as Silty/sandy rocks, clay r breccia tuffs with sandy rocks (yellow spots and very fragile), sandstone breccia mixed with clay, and clay rocks with brownish parallel layers. Based on the field observation, the debris material was dominated by rocks mixed with soi grey colo (Fig.10)

T
The size of debris was like very large weathered rockfall.

Specification
Types of debris material consist of sedimentary rocks, such as Silty/sandy rocks, clay r breccia tuffs with sandy rocks (yellow spots and very fragile), sandstone breccia mixed with clay, and clay rocks with brownish parallel layers. Based on the field observation, the debris material was dominated by rocks mixed with soi grey colored sandstone ( ig.10).

Type of Cikangkareng
The size of debris was like very large weathered rockfall. . 11 shows the size of rockfall debris compared to the size of the village house and size of the rocks.

Specification of debris material
Types of debris material consist of sedimentary rocks, such as Silty/sandy rocks, clay r breccia tuffs with sandy rocks (yellow spots and very fragile), sandstone breccia mixed with clay, and clay rocks with brownish parallel layers. Based on the field observation, the debris material was dominated by rocks mixed with soi ed sandstone (Fig. 9) and many fracture joint Soft grey sandstone Fracture joint

Cikangkareng
The size of debris was like very large weathered rockfall. 11 shows the size of rockfall debris compared to the size of the village house and F size of the rocks. Fig. 13 shows the type of jointed and fracture rock at the crown of the rockfall.
The size of rockfall debris of debris material Types of debris material consist of sedimentary rocks, such as Silty/sandy rocks, clay rocks (very fragile), breccia tuffs with sandy rocks (yellow spots and very fragile), sandstone breccia mixed with clay, and clay rocks with brownish parallel layers. Based on the field observation, the debris material was dominated by rocks mixed with soil. The type of rock is g. 9) and many fracture joint

Cikangkareng rocks
The size of debris was like very large weathered rockfall. 11 shows the size of rockfall debris compared to the Fig. 12 shows the varia 13 shows the type of jointed and fracture rock at the crown of the rockfall.

debris of debris material
Types of debris material consist of sedimentary rocks, ocks (very fragile), breccia tuffs with sandy rocks (yellow spots and very fragile), sandstone breccia mixed with clay, and clay Based on the field observation, the debris material was l. The type of rock is g. 9) and many fracture joint The size of debris was like very large weathered rockfall.
11 shows the size of rockfall debris compared to the 12 shows the variable 13 shows the type of jointed and Types of debris material consist of sedimentary rocks, ocks (very fragile), breccia tuffs with sandy rocks (yellow spots and very fragile), sandstone breccia mixed with clay, and clay Based on the field observation, the debris material was l. The type of rock is g. 9) and many fracture joint The size of debris was like very large weathered rockfall.
11 shows the size of rockfall debris compared to the ble 13 shows the type of jointed and  Fig. 13 Jointed rock and fractured rock exposed at the crown of rockfall

Type of test material
Various tests were performed on the debris material at Cikangkareng. They are summarized as follows:

Mineral
Feldspar minerals predominant in the debris material. Feldspar is a kind of mineral that consists of Al Feldspar is chemically divided into four groups of minerals, namely potassium feldspar (KAlSi feldspar (NaAlSi barium feldspar (Ba Al into clay due to the chemical weathering processes. These minerals are formed by varying different heat environments, during the crystallization of magma volcanoes in the earth and the process of sedimentation. The feldspar mineral could be used for ceramic or ceramic materials. It is an easy material to melt at low temperatures.
Cristobalite Quartz with the chemical formula SiO 2,32 and the hardness is about 6.5. The color of this mineral is white in the Feldspar, this mineral comes from the volcano. These minerals formed under high heat temperature that could reach 1470 o Celcius during the crystallization of magma volcanoes in the earth and the process of sedimentation.

Rockfall debris ( Rahardjo 6 Sept 09)
Jointed rock and fractured rock exposed at the crown of

of test material
Various tests were performed on the debris material at Cikangkareng. They are summarized as follows:

Mineral test
minerals and Cristobalite minerals were predominant in the debris material. Feldspar is a kind of mineral that consists of Al Feldspar is chemically divided into four groups of minerals, namely potassium feldspar (KAlSi feldspar (NaAlSi 3 O 8 ), calcium feldspar (CaAl barium feldspar (Ba Al 2 Si due to the chemical weathering processes. These minerals are formed by varying different heat environments, during the crystallization of magma volcanoes in the earth and the process of sedimentation. The feldspar mineral could be used for ceramic or ic materials. It is an easy material to melt at low temperatures.
Cristobalite is the mineral that belongs to the group of Quartz with the chemical formula SiO 2,32 and the hardness is about 6.5. The color of this mineral is white in the form of spots or lines. Similar to Feldspar, this mineral comes from the volcano. These minerals formed under high heat temperature that could Celcius during the crystallization of magma volcanoes in the earth and the process of sedimentation.
Notice the varying size of rocks ( Rahardjo 6 Sept 09) Jointed rock and fractured rock exposed at the crown of

of test material
Various tests were performed on the debris material at Cikangkareng. They are summarized as follows: and Cristobalite minerals were predominant in the debris material. Feldspar is a kind of mineral that consists of Aluminum (Al) and Silica (Si). Feldspar is chemically divided into four groups of minerals, namely potassium feldspar (KAlSi ), calcium feldspar (CaAl Si 2 O 8 ). Feldspar could degrade due to the chemical weathering processes. These minerals are formed by varying different heat environments, during the crystallization of magma volcanoes in the earth and the process of sedimentation. The feldspar mineral could be used for ceramic or ic materials. It is an easy material to melt at low is the mineral that belongs to the group of Quartz with the chemical formula SiO 2 2,32 and the hardness is about 6.5. The color of this form of spots or lines. Similar to Feldspar, this mineral comes from the volcano. These minerals formed under high heat temperature that could Celcius during the crystallization of magma volcanoes in the earth and the process of sedimentation.
Notice the varying size of rocks ( Rahardjo 6 Sept 09) Jointed rock and fractured rock exposed at the crown of Various tests were performed on the debris material at Cikangkareng. They are summarized as follows: and Cristobalite minerals were predominant in the debris material. Feldspar is a kind of uminum (Al) and Silica (Si). Feldspar is chemically divided into four groups of minerals, namely potassium feldspar (KAlSi 3 O 8 ), sodium ), calcium feldspar (CaAl 2 Si 2 O 8 ) and ). Feldspar could degrade due to the chemical weathering processes. These minerals are formed by varying different heat environments, during the crystallization of magma volcanoes in the earth and the process of sedimentation. The feldspar mineral could be used for ceramic or ic materials. It is an easy material to melt at low is the mineral that belongs to the group of with a density of 2,32 and the hardness is about 6.5. The color of this form of spots or lines. Similar to Feldspar, this mineral comes from the volcano. These minerals formed under high heat temperature that could Celcius during the crystallization of magma volcanoes in the earth and the process of sedimentation.

Notice the varying size of
Jointed rock and fractured rock exposed at the crown of Various tests were performed on the debris material at and Cristobalite minerals were predominant in the debris material. Feldspar is a kind of uminum (Al) and Silica (Si). Feldspar is chemically divided into four groups of ), sodium ) and ). Feldspar could degrade due to the chemical weathering processes. These minerals are formed by varying different heat environments, during the crystallization of magmavolcanoes in the earth and the process of sedimentation. The feldspar mineral could be used for ceramic or ic materials. It is an easy material to melt at low is the mineral that belongs to the group of with a density of 2,32 and the hardness is about 6.5. The color of this form of spots or lines. Similar to Feldspar, this mineral comes from the volcano. These minerals formed under high heat temperature that could Celcius during the crystallization of magmavolcanoes in the earth and the process of sedimentation.
However, Cristobalite crystal does not change due to weather or climate changes.

6.3
The slaking test conducted with the rotation of a cylinder which contains some pieces of rock samples in a water medium. In addition, this test is repeated in two cycles. After each cycle, the weight and dimension o measured. In this test, three rock samples are randomly chosen as the representative sample. results, it was found that the type of rock has "medium durability". This means that, in the first cycle, the remaining rock in th of the initial weight. Furthermore, in the second cycle, after the oven process, the percentage of remaining rock in the cylinder was about 60 However, Cristobalite crystal does not change due to weather or climate changes.

Slaking test
The slaking test conducted with the rotation of a cylinder which contains some pieces of rock samples in a water medium. In addition, this test is repeated in two cycles. After each cycle, the weight and dimension o measured. In this test, three rock samples are randomly chosen as the representative sample. results, it was found that the type of rock has "medium durability". This means that, in the first cycle, the remaining rock in th of the initial weight. Furthermore, in the second cycle, after the oven process, the percentage of remaining rock in the cylinder was about 60 However, Cristobalite crystal does not change due to weather or climate changes.

Wood fossil (sedimentary rock) test
The slaking test is a rock resistance test. This test is conducted with the rotation of a cylinder which contains some pieces of rock samples in a water medium. In addition, this test is repeated in two cycles. After each cycle, the weight and dimension o measured. In this test, three rock samples are randomly chosen as the representative sample. results, it was found that the type of rock has "medium durability". This means that, in the first cycle, the remaining rock in the cylinder amounted to 85 to 95 % of the initial weight. Furthermore, in the second cycle, after the oven process, the percentage of remaining rock in the cylinder was about 60 -However, Cristobalite crystal does not change due to debris rockfall due to the chemical The chemical test shows that the composition of the chemical is SiO2 (± 59%), and 8%), CaO (± 4%), LOI (±

Many colors of Cikangkareng Debris
Wood fossil (sedimentary rock) is a rock resistance test. This test is conducted with the rotation of a cylinder which contains some pieces of rock samples in a water medium. In addition, this test is repeated in two cycles. After each cycle, the weight and dimension of rock samples are measured. In this test, three rock samples are randomly chosen as the representative sample. From the test results, it was found that the type of rock has "medium durability". This means that, in the first cycle, the e cylinder amounted to 85 to 95 % of the initial weight. Furthermore, in the second cycle, after the oven process, the percentage of remaining rock 85% of the initial weight.
However, Cristobalite crystal does not change due to debris rockfall due to the chemical weathering The chemical test shows that the composition of the chemical is SiO2 (± 59%), and 8%), CaO (± 4%), LOI (± is a rock resistance test. This test is conducted with the rotation of a cylinder which contains some pieces of rock samples in a water medium. In addition, this test is repeated in two cycles. After each f rock samples are measured. In this test, three rock samples are randomly From the test results, it was found that the type of rock has "medium durability". This means that, in the first cycle, the e cylinder amounted to 85 to 95 % of the initial weight. Furthermore, in the second cycle, after the oven process, the percentage of remaining rock 85% of the initial weight.
However, Cristobalite crystal does not change due to weathering The chemical test shows that the composition of the chemical is SiO2 (± 59%), and 8%), CaO (± 4%), LOI (± is a rock resistance test. This test is conducted with the rotation of a cylinder which contains some pieces of rock samples in a water medium. In addition, this test is repeated in two cycles. After each f rock samples are measured. In this test, three rock samples are randomly From the test results, it was found that the type of rock has "medium durability". This means that, in the first cycle, the e cylinder amounted to 85 to 95 % of the initial weight. Furthermore, in the second cycle, after the oven process, the percentage of remaining rock

Point load test
The result of Direction Axial Longitudinal

Piezocone
The Piezocone to investigate the soil condition and debris thickness. But due to the limitation of penetration, it was only carried out at one point. The Piezocone test consists of a biconus, a pore stone, water seals, reading tools. Th is to identify soil stratification and in pressure. The According to CPTU grained was found se thickness. It The clay layer with medium to stiff consistency was found at GL m).

The volume
If the average thickness of the landslide was 10 m, then it could be estimated that the volume of debris was about 1 million m 3 . volume of debris material at Cikangkareng rockfall close to the other events.

load test
The result of the point load test is summarized in Table   Table 1 75-27.15 17.75-44.38 test was conducted at the toe of the debris to investigate the soil condition and debris thickness. But due to the limitation of penetration, it was only carried out at one point. The Piezocone test consists of a sounding rods and e purpose of the Piezocone (CPTU) test is to identify soil stratification and in-situ pore water 01 is at Cikangkareng. 01 the test results in Fig.16, a fine nsitive soil of about 3.2 m in indicates that this layer is landslide material. The clay layer with medium to stiff consistency was 3.2 m up to the end of testing (GL -

of material debris
If the average thickness of the landslide was 10 m, then it could be estimated that the volume of debris was about 19, it was observed that the volume of debris material at Cikangkareng rockfall oad test is summarized in Table 1 test was conducted at the toe of the debris to investigate the soil condition and debris thickness. But due to the limitation of penetration, it was only carried out at one point. The Piezocone test consists of a rods and ) test situ pore water Cikangkareng. , a finensitive soil of about 3.2 m in indicates that this layer is landslide material. The clay layer with medium to stiff consistency was -13.0 If the average thickness of the landslide was 10 m, then it could be estimated that the volume of debris was about that the was  The motion resistance from one end of the profile to the other w analyzed, the equal tan α, where α is the slope of the line connecting the crest of the source area with the toe of deposits measured on a straightened profile of the path [10] The volume of debris rockfall at Cikangkareng and the alpha is close to the graph which correlate and debris vol  show Cikangkareng against volume for 35 rock avalanches from Nort America and Europe. The dash [12] 8 Conclusion  The Cikangkareng areas landslide. An earthquake with a magnitude of 7.3 SR The motion of sliding block with constant friction resistance from one end of the profile to the other w analyzed, the frictional coefficient would theoretically tan α, where α is the slope of the line connecting the crest of the source area with the toe of deposits measured on a straightened profile of the path [10] The volume of debris rockfall at Cikangkareng and the alpha is close to the graph which correlate and debris volume ( see.

Relation volume
Landslides & Other Mass Movement . shows that the volume of debris rockfall at Cikangkareng was included on a plot of against volume for 35 rock avalanches from Nort America and Europe. The dash

Conclusion
The Cikangkareng areas landslide. An earthquake with a magnitude of 7.3 SR of sliding block with constant friction resistance from one end of the profile to the other w frictional coefficient would theoretically tan α, where α is the slope of the line connecting the crest of the source area with the toe of deposits measured on a straightened profile of the path [10] The volume of debris rockfall at Cikangkareng and the alpha is close to the graph which correlate see. Figs. 20 and debris and alpha (2) Landslides & Other Mass Movement s that the volume of debris rockfall at included on a plot of against volume for 35 rock avalanches from Nort America and Europe. The dashed line has a slope of 2/3 The Cikangkareng areas are susceptible to rock landslide. An earthquake with a magnitude of 7.3 SR Cikangkareng eng of sliding block with constant friction resistance from one end of the profile to the other w frictional coefficient would theoretically tan α, where α is the slope of the line connecting the crest of the source area with the toe of deposits measured on a straightened profile of the path [10]. The volume of debris rockfall at Cikangkareng and the alpha is close to the graph which correlated the alpha and 21) debris and alpha (2) Landslides According to CPTu-01, a grained soil were found consisting to approximately with 3.2 m in thickness. This indicates that this layer is a landslide material. A clay layer with stiff consistency was found at GL of testing (GL -13.0 m). The volume of debris rockfall at Cikangkareng and value of alpha are close which correlated the alpha and debris volume from he volume of debris rockfall at Cikangkareng included on a plot of the volume for 35 rock avalanches from Nort and Europe. The dashed line has a slope of 2/3 It is recommended that all areas under the crown of ckfall and should be sterilized from human settlement, the risk is still high. triggered a natural geological disaster that caused considerable damage. The Rock condition at the site is fractured, jointed an indication of old rocksl there is the possibility of fault reactivation due to the earthquake. Types of debris material consist of sedimentary rocks, such as silty sand rocks, clay rocks (easily fragile), Breccia tuffs sandy rocks (yellow sandstone breccia mixed with and Clay rocks with brownish parallel layers. The debris minerals of the Cikangkareng rockfall consist of Feldspar and Cristobalite and the chemical (± 59%), Al 2 O 8%), CaO (± 4%), LOI (± 6%). According to the slaking test, the debris material of the Cikangkareng rockfall is of medium durability. The point load index and uniaxial compressive strength in the axial and longitudinal directions are 7.75 to 27.15 MPa; 0.74 01, a mixed sand and grained soil were found consisting to approximately with 3.2 m in thickness. This indicates that this layer is a landslide material. A clay layer with stiff consistency was found at GL -3.2 m to the end The volume of debris rockfall at Cikangkareng and alpha are closely related which correlated the alpha and debris volume from he volume of debris rockfall at Cikangkareng the deposit area against volume for 35 rock avalanches from Nort line has a slope of 2/3 It is recommended that all areas under the crown of ckfall and should be sterilized from human settlement, the risk is still high. owledge the support provided by Parahyangan Catholic University.