IOM DEMOCRATIC REPUBLIC OF THE CONGO IOM’s Disaster Risk ... · 10/1/2014 · natural phenomena have caused signiﬁcant human and economic losses throughout the city’s history

SITUATION REPORT

IOM DEMOCRATIC REPUBLIC OF THE CONGO

IOM’s Disaster Risk Reduc on in North Kivu

Background

The Western branch of the Eastern African Ri is characterized by eight volcanoes located on the borders between Uganda, Rwanda and the Democra c Republic of the Congo. Of these volcanoes, only two (Figure 1b), on the Congolese side, are currently ac ve: Nyiragongo and Nyamulagira. On 17 January 2002, two lava flows from Nyiragongo volcano invaded Goma in a few hours, one of them reaching Lake Kivu. By the me the erup on ended, 13 per cent of the city was completely destroyed. The Nyiragongo showed for the second me in 25 years its devasta ng impact, leaving more than 200 persons dead and 130,000 people homeless. The city slowly recovered from this catastrophic natural event, and started expanding dangerously towards the volcano. Houses rapidly colonized the newly formed lava, o en the only land affordable to the hundreds of thousands of newcomers who arrived in the city fleeing conflict and economic hardship or a racted by local income opportuni es, mostly unaware of the risks they were facing. Today, Goma is considered to be one of the most dangerous ci es on the planet from

the natural disaster viewpoint. It is built between the two most ac ve volcanoes in Africa and on the shore of a lake with a gigan c carbon dioxide and methane reservoir at its bo om, in a highly seismic region exposed to deadly natural carbon dioxide emissions from the soil, acid rains due to the scrubbing of the big volcanic plume by rain waters, landslides and mudflows, which have caused tenths of deaths in recent past, and lacking access to good‐quality groundwater. All these natural phenomena have caused significant human and economic losses throughout the city’s history. Over the last decade, though, rapid popula on growth has created the condi ons for an exponen al increase in disaster risk. For the above reasons, Disaster Risk Reduc on Programmes are highly needed for the city of Goma. IOM, as the Camp Coordina on and Camp Management lead agency in natural disaster situa ons, is implemen ng a pilot project that started in February 2014, directly par cipa ng to build a con ngency plan that will help enhance the capacity of several government en es (e.g. the Goma Volcano Observatory and the Civil Defence of the Democra c Republic of the Congo) as well as increase awareness, preparedness and resilience of the local popula on.

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UPDATE 01 October 2014

In this issue

Background

Why build a

con ngency plan

Mount Nyamulagira:

Ac vity, scenarios,

possible

consequences and

human interac on

Mount Nyiragongo:

Ac vity, scenarios,

possible

consequences and

human interac ons

Historical ac vity

of Mount

Nyiragongo

Forecast for the

volcanic ac vity

of Nyiragongo

Figure 1a. The city of Goma a er the Nyiragongo volcanic erup on of 17 January 2002. © IOM 2002 (Photo: Dario Tedesco)

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Why build a con ngency plan A con ngency plan (CP) represents the main tool authori es deploy in the event of a large‐scale and catastrophic event occurring in their community. In the plan, necessary arrangements are made in advance to enable mely, effec ve and appropriate responses to any crisis. A CP, specifically one related to natural disaster preven on and/or mi ga on, is based on scenarios of possible natural disasters (e.g. volcanic erup on, earthquake, flooding, landslide and mudflow). This type of CP is based on past natural disasters and their severity. The possibility that these events will occur in the future allows a community to build a plan in order to mi gate damages caused by these future hazard occurrences. Apart from surveillance ac vi es and scenarios, the CP involves coordina on and ins tu onal preparedness, and educa on and sensi za on of, and communica on to, at‐risk communi es in order to increase local preparedness and resilience. Past events are studied and interpreted by scien sts. Their work needs to be as accurate as possible, looking into the available literature and, most of all, conduc ng field studies. This will allow for the development of a clear understanding of the poten al for future events.

In geology, the general principle is that “the past is the key to the future”. However, for natural occurrences such as landslides, flooding and mudflows, some mes climate is the major factor. The said principle is always true for volcanic erup ons and earthquakes which tend to have return periods that are close to the dura on of human lives: an erup on or a quake that occurred hundreds or over just tens of years ago may be ready to happen again. To create an ac onable CP, scenarios and models of past ac vi es represen ng the future events need to be constructed, taking into account a large variety of informa on. The two main factors to consider are the impact scale (measured in terms of loss of lives or proper es for an event of a given intensity) and the probability of occurrence (the sta s cal likelihood that an event of a given strength will occur in a certain period). The second parameter is extremely difficult to correctly evaluate. The CP is a strategic document or tool any community facing natural or human‐made hazard should have in order to mi gate and/or prevent damages to property and loss of lives, though the role of the CP in this aspect could be limited. It is, by defini on, an extremely dynamic tool that should be changed any me the condi ons of a hazard source (e.g. a volcano) or of the community at risk change. The la er would be the case of a marked popula on increase or land use change in the hazard exposed area.

Contact: Laurent DE BOECK, Chief of Mission, IOM Democra c Republic of the Congo | [email protected] | www.drcongo.iom.int

Figure 1b. The two only ac ve volcanoes located within the area, Nyiragongo and Nyamulagira, are located at the central part of the Western branch of the Eastern African Ri .

Mount NYIRAGONGO

Mount MIKENO

Mount NYAMULAGIRA

Mount KARISIMBI

Mount VISOKE

KILOMETRES

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Mount Nyamulagira: Ac vity, scenarios, possible consequences and human interac on The Nyamulagira volcano is considered, in terms of erup ve events, the most ac ve in Africa. An average erup ve event from the volcano usually lasts from few weeks (like the erup on on 2–27 January 2010) up to three years (such as the erup ve event in 1938–1940). In the past 80 years, an erup ve occurrence has taken place generally every two or three years. Mount Nyamulagira is considered less dangerous than its neighbour, Mount Nyiragongo, as the former is more distant from any major urban centre. However, Mount Nyamulagira’s plume might present a threat for local popula ons and flights opera ng in the area. In recent years, the town of Sake has been rapidly expanding northwards, whose popula on now stands at more than 100,000. Nyamulagira is becoming a greater threat due to this expansion of human se lements. Its ac vity, therefore, needs to be taken into account, and monitoring must become a priority. Its lava flows can be extremely fast due to the low viscosity (poor‐silica content) of the lava. Mount Nyamulagira also demonstrates much higher lava flow rates and volumes of magma erupted than Mount Nyiragongo. Below are two poten al scenarios. The first scenario in Figure 2a (which occurred in 2000, 2002, 2004 and 2011)

shows ac vity concentrated to the north, north‐eastern and north‐western sides of the volcano. In contrast, Figure 2b (which occurred in 2006 and 2010) shows a scenario in which lava will flow towards the southern flank of the volcano. Erup ons of Nyamulagira are generally preceded by a series of smaller and related volcanic seismic events. In these events, local seismicity, rarely felt by humans, in the form of seismic swarms, occurs under the push of the rising magma. It can last between few hours and few days. These smaller events, if adequately monitored, can be a detectable warning of an incoming erup on. However, several seismic swarms, over the course of several months or years, can take place before an erup ve event will occur. Determining if the erup on will occur through the northern or the southern flank of the volcano is a major difficulty. The seismicity will produce cracking of the volcano and the (re)ac va on or opening along the flank of its erup ve fractures (Figures 3a and 3b). Before the lava reaches the surface, emission of smoke will increase from different parts of the volcano, mainly from the most fragile areas (such as the last erup ve sites and old fractures). Visual observa ons of these sites combined with recording of the seismic ac vity and possibly satellite data can help to figure out where the erup on will


Figure 2a and 2b. Two possible scenarios: (a) flow to the north/east or west; (b) flow to the south.

Figure 3b. A part from the fractures from the main crater of Nyamulagira, the photo also shows the 2010 erup ve cone being the terminal/con nua on of two main "scars" on the southern flank of the volcano.

Figure 3a. The photo shows fractures from the crater of Nyamulagira to the southern flank.

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likely take place. The erup ve ac vity usually starts with intense lava fountains (Figure 4a) several hundred metres high. A spa er cone (Figure 4b) will then form from the accumula on of fallen materials (e.g. ashes, scoria and lava). Finally, a lava flow will form and run the higher‐slope path (Figure 3b).

The first area affected in both scenarios previously discussed is the Virunga Na onal Park. Scenario B shows that the inhabited areas of Sake and Mubambiro, south of the volcano, could be also affected. In scenario A, showers of ashes and/or scoria could cause problems for ca le and crops (agriculture) mainly in the west. The severity of damages would therefore be a consequence of where the erup ve vent will open and how far human se lements or ac vi es are located from the vent. Volcanic products in the plume may travel for tens of kilometres depending on the size and height of emissions. Only the Tongo–Kalengera road (north‐eastern side of the volcano) may be affected (scenario A) in the case of an extremely long lava flow (Figure 2a). In this scenario, recovery would be rapid, as the flow would be primarily in areas with limited or no concentra on of people and assets. Scenario B (Figure 2b) shows the same characteris cs of scenario A; however, its impact is far greater due to the presence of inhabited areas (Figures 5a and 5b) in the zones affected. The only physical difference between

these two scenarios is that they would start from different points at varying al tudes. An erup on from a lower point of origin (and closer to urban se lements) would probably be characterized by interac ons between the rising magma and the groundwater located at shallow depth, causing phrea c explosions. If the urban areas of Sake and Mubambiro will be targeted by an erup on in the future, more than 100,000 people might need to be evacuated. The Sake–Goma and Sake–Kitchanga road axes may also be cut, crea ng severe problems to the local economy by blocking exchanges between the two main urban areas. The erup ve event may produce further direct disrup on by pollu ng water sources with volcanic products or by injec ons of acidic fluids into the groundwater table used by the local popula on. In addi on, volcanic par cles and gas from the plume that is constantly produced by the two volcanoes may create respiratory problems, mainly affec ng babies, the elderly and those already suffering from respiratory pathologies (e.g. asthma). Whenever the plume reaches the neighbouring villages, people minimize the health hazards linked to the inhala on of acidic gases (e.g. SO2, HF, HCl) through simple measures such as covering their mouth and nose with a wet ssue when breathing.


Figure 5b. View of Sake next to the li le bay of Sake. The small lake on the

right side of the photo is the product of the largest known historical lava

flow from Nyamulagira volcano which occurred from 1938 to 1940.

Figure 4b. The photo shows a macro image of the lava fountain. Volcanic scoria s ll melt and accumulate along the flanks of the volcano.

Figure 4a. Lava fountain of the 2011/2012 erup on event at Nyamulagira. The con nuous accumula on of volcanic materials (scoria/spa ers con-tained within the lava fountain) resul ng in the forma on of the cone.

Figure 5a. Aerial view between Sake and the bay of Kabuno, taken from the

periphery of the southern flank of the volcano.

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Disrup on of agricultural produc on should also be taken into account. If the road between Sake and Goma will be cut, there will be nega ve effects on the transporta on of food and charcoal to Goma where 50 per cent of fresh food and 70 per cent of charcoal used by the 1.1 million inhabitants are coming from the western side of the ri . Possible social unrest could result from this scenario. Scenario B should be taken into serious considera on by local authori es, humanitarian agencies and non‐governmental organiza ons. Possible measures to prevent a disaster should be discussed. The possible disrup on of many ac vi es could last for months or even years in func on of the dura on and intensity of the erup ve event. In the worst recorded case, erup ve ac vi es con nued uninterrupted three years, between 1938 and 1940. As a consequence, almost 7 kilometres of road were destroyed by the lava flow, and transporta on was interrupted for more than two years. The Civil Defence of Goma, under the auspices of the Governor, is currently taking the lead in outlining the new CP of the city, discussing and upgrading the 2009 plan. Together with the Goma Volcano Observatory (GVO) and IOM, the Civil Defence of Goma will be reviewing the possible scenarios. The current GVO seismic network is undersized for the area needing to be covered. However, increasing the number of seismic sta ons will have a posi ve impact only if collected data is sent to the Observatory by telemetry in real me. Instead, seismograms today are manually retrieved at best twice a week, due to bad road condi ons and lack of funding. If correctly combined, data from visual and satellite observa ons and seismographs could allow the GVO to properly interpret pre‐erup ve signals. Having more sta ons could poten ally give the GVO more warning me, which could save a large number of lives in case of a serious erup on.

Mount Nyiragongo: Ac vity, scenarios, possible consequences and human interac ons Historical ac vity of Mount Nyiragongo Mount Nyiragongo’s ac vity over the past 70 years has been generally different from that of its neighbour, Mount Nyamulagira. Its ac vity was predominately concentrated within its crater containing the most spectacular lava lake on earth (Figure 6). For this reason, its outside crater erup ve events are scarce and not well known. Records and data only exist for the erup ons of 1977 and 2002. For comparison, since 1977,

Nyamulagira has experienced more than 20 erup ve events. Both these erup ons at Nyiragongo have been characterized by fast‐moving lava flows causing destruc on and loss of lives next to the southern flanks of the volcano and, in 2002, in the city of Goma. In both cases, the lack of knowledge of the volcano, preparedness, informa on‐sharing and communica on between the different actors were crucial factors in determining the amount of assets and lives lost. During the la er erup on, some data was collected by the seismic sta on network funded by the United Na ons High Commissioner for Refugees in 1995. By 2002, only two (Bulengo and Katale) of the ini al five sta ons were func oning, the others having been looted or destroyed. The data collected has been used to build models of the volcano’s inner workings. Before the 2002 erup ve event, there was no ac vity within the crater. The volcano was in a quiescent state (absence of a lava lake at its bo om) and there had been no lava lake since August 1995. Almost one year before the erup on, the GVO started recording an anomalous seismic ac vity, with con nuous seismic swarms and volcanic tremors. It was clear to the GVO researchers that new magma was breaching through the volcano and moving up to the surface but no one could know when, where and how this magma would have erupted. There simply was not enough data and observers did not have enough experience, being the first me they observed such an ac vity, to make the correct forecasts. The erup on occurred without warning and local authori es did not provide the popula on with mely informa on concerning exis ng hazards and the need to evacuate, in spite of the scien sts’ advice. As a consequence, most of the popula on fled the area only a er the erup on, when parts of the city were already burning.


Figure 6. Nyiragongo’s astonishing lava lake.

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For the con ngency plan, two scenarios have been chosen: the first one (Figure 7a) is similar to both 1977 and 2002 events, while the second (Figure 7b) is related to a single erup ve event, of much larger magnitude, similar to the one that occurred about 650 years ago.

Forecast for the volcanic ac vity of Nyiragongo Erup ve events at Nyiragongo will be an cipated by intense seismic ac vity. This is the only similarity to the ac vity occurring at Mount Nyamulagira. Based on the experience of the 2002 erup on, however, this ac vity might take place over a longer period, possibly las ng several months. This should be the case if the volcano is in a quiescent state. Conversely, if the magma is already close to the surface, the me span of its pre‐erup ve seismic ac vity will be reduced to weeks or even days. In the first case, there will be more me to prepare for an evacua on and implement the CP. In the second case, the evacua on plan might be put into ac on in close proximity to the date of erup on.

It is possible, as in 2002, that a number of earthquakes of medium energy with a magnitude between 4 and 5 will precede or trigger the erup on and possibly be felt by the local popula on. This seismic ac vity would then be responsible for the reac va on of the fault system on the already fractured southern flank of the volcano, thereby facilita ng the magma to proceed towards the surface and ul mately to spill out. As in 2002, increasing soil temperatures, due to the migra on of volcanic fluids and gases in areas next to the erup ve event, might be detected. In some cases, new ephemeral fumaroles may form. Similarly, opening of new fractures will occur before, during and a er the erup ve event. In 2002, several fractures opened near or within the city of Goma. Gas anomalies, mainly methane emissions, were recorded in several places within the city and its outskirts. Due to this fracture system that developed in 1977 and later in 2002, there is a chance that the future erup ve event may start directly within the city of Goma (Figures 8a and 8b).


Figure 8b. The photo shows a fracture opened during/a er the volcanic erup on in 2002.

Figure 7a. This figure and Figure 7b show the two scenarios proposed to local authori es, humanitarian agencies and non-governmental organiza-

ons. They have been formulated from the li le ac vity historically known of Mount Nyiragongo. In the first case (a), the erup on will occur star ng from the southern flank of the volcano and then evolving only par ally

Figure 7b. The second scenario, will involve the en re city. Although these two events (a + b) are sta s cally more likely to occur, a third possible scenario, which has already occurred in the past, must be taken into ac-count. Please see the small circle next to the Goma harbour in Figure 7a. It is one of the many peripheral cones of Nyiragongo volcano. A possible erup on may occur directly within the city. This event has already occurred several mes in different areas within the city. Of the several remaining cones, one is Mount Goma. They show the evidence that this ac vity may occur again.

Figure 8a. Fractures that opened in the outskirts of Goma during the 2002 erup ve event. Most of the fracture system causing the erup on opened chronologically at the same me of the erup on or immediately a er. The fracture just north of the city of Goma in 2002 ( today because of the expan-sion of the city, it would be within the city’s limits).

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The 2002 event was characterized by an extremely short pre‐erup ve phase, with very limited me for warnings. As part of preparedness efforts for future, poten ally similar events, it is important that the popula on of Goma is well aware of, and trained on, how to best react in the event of a new erup on. Another crucial point that needs to be taken into considera on is the growth in Goma’s popula on; from 2002 to 2014, the size of the popula on has nearly tripled (from 400,000 to 1.1 million). With this growth, a huge percentage of the popula on has not experienced an erup on and therefore might be ill prepared and not aware of the correct procedures to follow. In addi on, the city of Goma, with its recent expansion, is now much closer to the volcano (Figures 9a and 9b).

Due to the increase in the number of people exposed to volcanic hazards and the low level of awareness, the city of Goma is much more vulnerable today than in the past. The risk the city and its inhabitants are facing has increased exponen ally because of these dynamics. In addi on, study of past volcanic ac vity within the city

and its surroundings has shown that there is a third scenario that should be taken seriously into considera on. There is the possibility that, similar to what happens at Nyamulagira, the erup ve event at Nyiragongo volcano may not start from its upper southern flank, as it occurred in 1977 and 2002, but may take place at a certain distance from the central crater and its high flanks. Within the city of Goma there are visible traces (Figures 10a and 10b) of a different kind of volcanic ac vity, in the form of small cones, remnants of erup ons that occurred in a more or less distant past. It is important to know the age of these cones in order to understand and quan fy the current hazard, but these dates are s ll unknown. As they are quite similar to some which occurred around Mount Nyamulagira in the recent past (e.g. crater of Rumoka between Goma and Sake, formed in 1912), one can assume these cones to be very young in geological terms (tens or hundreds of years from present), therefore suscep ble to reoccurrence in the near future.


Figure 9 a and b show two different images of the con nuous parcelling of the area covered by the 2002 lava flow. The whole lava flow has been par-celled and sold. Houses are growing like mushrooms and ge ng always closer to the volcano. The hazard calculated from increases in the number of households and the proximity of the volcano is exponen ally growing.

Figure 10b. The photo shows smaller cones in the western periphery of the city, surrounded by the expanding city. A programme on educa on, sensi -za on and informa on is strongly needed to correctly inform the local pop-ula on and its authori es of the increasing volcanic hazard.

Figure 10a. Mount Goma, hos ng the port of the city, is the best example and a clear evidence of the peripheral ac vity of Mount Nyiragongo. The crater is built on ashes, a product that forms not very commonly in the Virunga area, at least not in such huge amounts. The presence of ashes is an evidence of the explosive feature of this ac vity and increases hazard and vulnerability of the popula on.

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Mount Goma, which today harbours the city’s port, is the best example of this third possible scenario and makes a perfect case for why these events and their poten al consequences to the different areas of Goma should be studied (Figure 10a). Its forma on is due to a volcanic process (explosive) completely different from those witnessed in 1977 and 2002 (effusive). An explosive volcanic event in the middle of a highly populated urban area would be way more destruc ve and deadly than lava flows from the city’s outskirts. Depending on the magnitude of the erup on, fine ashes might be distributed in an area of tens of square kilometres from the volcano and every single structure in its proximity destructed. Previous studies have shown that such volcanic ac vi es have frequently occurred in the past, their signs being s ll visible within and around Goma. The explosive feature is facilitated by the presence of groundwater and Lake Kivu. The interac ons between magma and water while magma is moving to the surface are responsible for highly explosive ac vity.

Interac ons between water and magma produce small‐scale strombolian ac vity (characterized by con nuous mild explosions) and pyroclas c ac vity (clouds of ashes and fine grained scoria ejected at high velocity and high temperature), poten ally affec ng the popula ons living in areas up to a few kilometres around the volcanic cone. Scenarios of Mount Nyamulagira and Mount Nyiragongo show the need for increasing the level of monitoring and surveillance while capitalizing on collabora ons with interna onal scien fic ins tu ons. Increasing the quality of programmes dedicated to sensi za on and educa on of the local popula on, in order to increase awareness, preparedness and ul mately resilience, will also be

necessary. It is only through structural and non‐structural investments in disaster risk reduc on, based on sound scien fic knowledge and involvement of all stakeholders at the community and the ins tu onal levels, that a safe future for local popula ons can be achieved.


For more informa on, please contact: Dario TEDESCO, Disaster Risk Reduc on Specialist, [email protected], +243(0)81 664 5057 Monique VAN HOOF, Emergency Programme Coordinator, [email protected], +243(0)82 248 7445

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IOM DEMOCRATIC REPUBLIC OF THE CONGO IOM’s Disaster Risk ... · 10/1/2014 · natural phenomena have caused signiﬁcant human and economic losses throughout the city’s history