FLOODS

1. Characteristics and types.

Floods are common natural disasters on the territory of the Republic of Bulgaria. They cause enormous damage as they affect populated areas, industrial areas and productive agricultural lands.

Floods are usually the result of overflowing rivers, of sudden sea and ocean level rise, of intense rainfall and/or intense snowmelt, of blockage of the stream in the river bed due to the accumulation of debris, rock material and trees, leading to a reduction its throughput.

In accordance with the scientific classification for this type of disaster, the following types are typical for the territory of a country:

• floods from river overflows;

• flash floods;

• floods from accidents and improper management of hydrotechnical facilities;

• floods caused by deliberate actions.

Flooding from river spills

River overflows occur when rivers overflow their banks and the incoming high waters spill over their river terraces. The reason for this is the drastic increase in river runoff (due to intense rainfall with rare recurrence and snowmelt), as well as of a different nature - overgrown riverbeds, clogged drains from deposited sediments and entrained woody material, congestion (surges) from ice drifts or from wind impact and others.). The wind impact is typical for our Black Sea rivers, when in case of a sea wave of more than 7 points, there is a significant congestion (surge) of the water in the mouths.

Flash floods

Flash floods are caused by the formation of water on the earth's surface during intense rainfall. When the intensity of water formation exceeds the estimated runoff module of the terrain or the actual runoff module of the constructed sewerage and drainage systems, large volumes of water are formed on the earth's surface, which flow down in the form of torrents and fill the low terrain forms. Flash floods are not related to the presence of a river network and can occur after intense rainfall, regardless of the state of the water regime in it.

Flash floods are especially dangerous for urban areas, where impermeable, smooth roofs and street surfaces create conditions for high water velocities, rapid concentration and almost no losses from infiltration into the soil.

A similar effect also occurs in land with a large slope of the bottom and cliffs, where the rapid concentration of runoff waters is able to generate catastrophic high waves with very little durability.

Floods from accidents or mismanagement of hydrotechnical facilities

This type of flooding is mainly due to two main reasons:

• accidents at large hydrotechnical facilities;

• improper management of dams, mainly with a large hydraulic capacity of the relief facilities.

In both cases, especially in the first case, heavy floods can occur in the sub-reservoir section, which are particularly dangerous due to their unexpected occurrence, even in calm hydrometeorological conditions.

The small municipal dams are a particular danger, due to the fact that the walls and their relief facilities are not maintained in technical condition and technical control is not carried out in accordance with the requirements of the regulatory framework.

Floods of deliberate action.

These are artificially induced floods as a result of deliberate actions directed against the security of the country. The objects of a deliberate attack to cause a flood can be large hydrotechnical facilities, such as dam walls, leveling basins, reservoirs, large pressure pipelines, large diversion canals, etc.

A significant part of the territory of Bulgaria is mountainous. On the territory of our country, nearly over 2,000 rivers form the watersheds of 17 main rivers, as well as the watersheds of the rivers flowing into the Black Sea from the northern to the southern border. The outflow of the rivers in Bulgaria is very different in the summer, when it is minimal, and in the spring, when the river level rises sharply due to rain and snowmelt. Due to the mountainous nature of the terrain in our country, floods last a shorter time, but are more difficult to predict and have a short response time.

The most complicated situation due to flooding can be expected in the lowlands and along the Danube, Maritsa, Tundzha, Mesta, Iskar, Arda, Kamchia rivers, as the size of the flooded areas. Significant flooding can occur along the Danube River with intense snowmelt in the Alps in May, and in February and March as a result of ice drifts, endangering about 500,000 people and about 73,000 acres of agricultural land.

Man-made floods caused by the destruction of the dam walls of the Iskar, Batak, Trakiets, Ogosta and Topolnitsa dams can have catastrophic consequences, in the floodplains of which 910 square kilometers and about 650,000 people fall.

 

2. Measures to reduce the risk of flooding

 

After the development and adoption of the flood risk area maps, as the next stage in the implementation of the Floods Directive, Flood Risk Management Plans (FRMPs) should be developed. Programs of measures aimed at prevention, protection and preparedness, including flood forecasting, construction of early warning systems, sustainable land use, improvement of the retention capacities of the territories, etc., are planned to be laid down in them.

Flood risk reduction measures are part of preventive action within the meaning of the Disaster Protection Act. By priority, they should be included in the annual plans for the implementation of the National Disaster Protection Program, as well as be taken into account when developing the Disaster Protection Plans at the corresponding level. (regional, municipal). For this purpose, it is foreseen in the Program of measures in the PURN to specify the territorial-administrative units, responsible persons, deadlines and necessary means for their implementation.

The update of the Flood Risk Management Plans is planned to be carried out every 6 years, taking into account the impact of climate change (first update of the PFRN by the end of 2018, the maps by the end of 2019 and the PFRN by end of 2021).

In connection with the development of the NAP, in the near future, it is planned to prepare a "Catalogue of goals and measures for flood risk management" and a "Methodology for evaluating the costs and benefits of the measures provided for in the NAP".

The main measures to reduce the risk of floods, which should be implemented until the adoption of the NAP and which would be included in the programs of measures, are the following:

• maintaining the conductivity of river beds, incl. in the 500-meter zone after the dams;

• maintenance and operation of dams, corrections of rivers and ravines and other hydrotechnical and protective facilities, drainage systems and fields, drainage pumping stations (OPS);

• annual spring and autumn technical inspections of the hydrotechnical facilities, ending with the preparation of protocols, in which the repair and investment works for the following year are marked;

• preparing an analysis of the technical condition of each dam wall once every three years;

• preparation and implementation of emergency plans for dam areas and allocation of emergency warehouses, equipped with the necessary equipment and materials;

• construction of modern notification systems (in part of the dam areas - "Iskar" dam area and "Kardjali" dam area);

• liquidation of potentially dangerous dams whose technical condition does not allow their further exploitation.

• construction and maintenance of storm sewers;

• construction of thresholds and barriers in front of the entrances of the buildings in the threatened low areas of the terrain;

• tightly closing the vessels in the shafts in which polluting materials and hazardous waste are stored;

• provision of the necessary means for protective and rescue activities and for providing first aid, periodic checking of their suitability and their timely replacement;

• ensuring and maintaining in working order the means of disclosure;

• keeping the employees and workers in the port terminals well informed - each one of them is familiar with his assigned duties when performing the rescue and protection activities and the necessary tools;

• carrying out periodic trainings to make the terminals ready for actions in disaster conditions;

• optimization of the organization for carrying out protective and rescue activities on the territory of the municipality (region, site);

• ensuring readiness for carrying out repair and restoration works on the territory of the municipality (district, site), in case of destruction and damage;

• approval of the procedure for resuming work on the territory of the terminals, if their activity was suspended.

 

3. Protection of the population during floods.

 

In the event of a flood, the National Disaster Management Authority performs the following activities:

1. reconnaissance in the flooding area and the places where people, animals or material values may be blocked by the water.

2. removal of people or animals, as well as removal of material values from flooded areas.

3. inspections of the state of the roads and approaches to the flooded area and for settlements without access due to flooded roads.

4. in the case of data on the presence of industrially toxic substances (POS) or other substances in the flooded area that are in danger of causing damage or causing environmental pollution, conduct reconnaissance of the storage places and, if possible, take measures to prevent pollution.

The ways to remove the population or animals, as well as to remove the material values during a flood are:

1. export/export by watercraft.

2. removal/removal with companions (in the absence of a current or speed up to 0.2 m/s, height of the water column up to 1.2 m and the possibility of independent movement of the injured).

3. removal/removal using alpine methods.

4. removal/removal by using high-passable or floating equipment.

Rescue operations begin with:

1. organizing the disconnection of the power supply in the flooded area through OKITC.

2. rescuing people in the flood zone.

If it is impossible to remove all the injured in a short time to the designated places, food, water, medicines, warming drinks, clothes or blankets, provided by the local authorities, will be transported for those who will be removed later, if necessary.

Regardless of the situation, pregnant women, mothers with young children, the bedridden, the disadvantaged, the chronically ill, whose treatment requires periodic visits to hospitals (for example, hemodialysis), according to preliminary lists provided by the local authorities, are the first to be removed.

Particular attention is paid to the removal of people from hospitals, from homes for children without parents or deprived of parental care and from homes for the elderly.

The removal of patients from institutions for the treatment of the mentally ill is carried out after coordination of the actions with the relevant specialists and under their supervision and instructions.

After the removal of the people, measures are taken to remove the POW, radioactive sources and other substances that, in the situation that has arisen, could cause harm to people or pollution of the environment. For this purpose, their type, quantity, packaging, location and condition at the time of the flood are determined with the help of the relevant heads of enterprises, etc., who are the owners of the same. After the information received, the priorities for actions are determined and an on-site inspection is carried out by the rescuers and by specialists in the relevant field, specifying:

1. the order and sequence for packing and export.

2. the places of delivery and storage after export.

3. the teams, equipment, apparatus and technique necessary for export.

4. the need for special measures to neutralize them or reduce their harmful impact.

5. the need for specialized medical teams.

6. the means, forces and means for export.

7. the additional safety measures for each individual case.

Salvage works also include:

1. removal of movable cultural assets from the flood zone, for which purpose their preparation for removal is carried out by relevant specialists in this field.

2. removal of animals from the flood zone.

3. extracting, if necessary, stuck cars or other equipment.

Rescue workers must wear life jackets or vests.

If necessary, the diving teams from the Main Directorate "National Service "Civil Protection" are used, observing all the requirements for the organization of the diving activity.

 

4. Snowfall and snowstorms. Heavy snowfall, blizzards, icing and avalanches

 

The specificity of the continental climate is the basis of possible snowfalls. Snowstorms and icing are a frequent phenomenon in our country. They are characteristic of December and January, but can also occur during the other winter months. Snowstorms and icing lead to the destruction of air communications, blocking of roads and can put the lives of many people at risk.

Snowfalls can be disastrous mainly in populated areas, where they impede, and often completely block, all types of transport for different periods of time.

Heavy snowfall accompanied by strong winds is a serious problem in winter. As a result, snowdrifts form, which block the transport infrastructure of the country.

Cold temperatures are the cause of icing on power lines and other exposed communication lines.

Avalanches occur as a result of a violation of the static stability of the snow cover, and their movement along the slope is under the influence of gravitational forces.

Avalanches in Bulgaria are a relatively rare phenomenon, but in some places in the high mountains, and primarily in Rila and Pirin, the conditions for avalanches are created. According to data from the Mountain Rescue Service in Bulgaria, an average of 2-3 people fall victim to avalanches per year.

 

5. Protection of the population during heavy snowfalls.

5.1. General rules.

During heavy snowfalls, difficulties are created in people's daily life and activities, resulting in:

1. violation of transport communications.

2. power failure.

3. disruption of the water supply.

4. disruption of communication links.

5. Blocking of populated areas as a result of accumulated debris.

6. disruption of the supply of the population with bread and basic necessities.

7. complicating the supply of solid and liquid fuels for heating.

8. difficulties in transporting patients, women in labor, needing hemodialysis to specialized hospital facilities, etc.

9. difficulties in moving medical teams to villages blocked by snow.

10. difficulties in the functioning of the transport network.

11. formation of avalanches and avalanche sections and blocking of tourists in the mountains.

Actions in the event of heavy snowfall are aimed at carrying out life-saving measures that ensure normal living conditions for the population.

5.2. Peculiarities of actions during snow drifts.

In the case of cars buried by snowstorms, the following actions are carried out:

1. specify the location of the overturned (crashed) motor vehicle, the number of passengers and their condition, the type of motor vehicle and its registration number, the presence of dangerous or other loads.

2. rescue activities are carried out depending on the situation, with the overwhelmed vehicle being pulled out or only the passengers being taken out; the need to attract additional forces and means from the unified rescue system is determined.

3. a team is formed, equipped with an all-terrain vehicle or tracked machine (MTLB or ATS).

4. medicines, blankets, water, medical equipment and means of marking and lighting are taken.

5. the means of communication are checked and an instruction is given on the measures for safe working conditions.

6. when approaching the designated place, check for the presence of uncharacteristic elevations, piles or vehicles; if found, they are checked.

7. if the motor vehicle is visible and there is an opportunity to be towed, first contact is established with the occupants, their condition and reported in the О "АСД".

8. the passengers are taken out and the vehicle is withdrawn.

9. in the event that the discovered motor vehicle is not the same as the one for which the signal was received, it is reported to O "ASD", the passengers are evacuated, technical assistance is provided to the motor vehicle (if possible), after which the search continues according to the received signal.

10. if necessary, medical assistance is provided to the passengers, and in the presence of symptoms of frostbite, the victims are transported to the nearest health facility.

11. if there are dangerous or valuable cargoes in the motor vehicle and it cannot be towed, it is immediately reported and its security is organized; if the driver refuses to be taken out, he is provided with food, hot drinks, blankets and fuel.

12. in case the driver is a foreign citizen, his passport data are recorded, which are handed over to the person on duty in the operational communication and information center (OKITC) of the district.

 

If a train is stuck in a sleeper, the following actions are taken:

1. specify the place of the train, the number of passengers and the possibilities for heating the carriages.

2. contact is established with the mayor of the nearest populated place to organize the accommodation of the passengers.

3. contact is established with the necessary forces from the unified rescue system to organize the conduct of the rescue activities.

4. prepare: all-terrain vehicles (APP), chain machines, medical equipment and medicines, hot drinks and blankets, means of signaling and lighting, stairs.

5. upon arrival at the location, the APPs remain on the road, marking it and illuminating the area.

6. after the opening of the train, the removal of the passengers is organized, with priority being given to the sick, pregnant women, mothers with small children, and the elderly; passengers are given hot drinks and blankets.

7. ladders and other aids are used in rescue operations.

8. in the event that prisoners are escorted on the train, they are taken out last, and the security measures and their transportation from the train are organized by the authorities of the Ministry of Internal Affairs.

9. the train master receives information about the transported particularly important, valuable or dangerous goods; if there are any, it is immediately reported to the district's OKIC and security is taken over by the authorities of the Ministry of Internal Affairs.

When transporting pregnant, sick and chronically ill people in need of specialized treatment, etc.:

1. a medical team is called in for the rescue activities conducted by O "ASD"; the movement is carried out by APP, MTLB or ATS, providing suitable conditions for transporting the patient according to the requirements of the medical team; if it is impossible to provide a medical team, the patients are accompanied to the hospital by a local medical person.

2. before starting rescue operations, specify the illness, the need for evacuation, the type of medical assistance, the three names and addresses of those in need.

3. upon arrival at the location, the condition of those in need is immediately reported.

4. the responsibility for the life and health of those in need rests with the medical team (medical person) accompanying the victim.

The rescuers assist in the delivery of food, water, medicine and essential goods to the residents of the disaster areas if necessary.

6. Landslides

6.1. Essence of the problem.

Landslides are one of the most significant catastrophic phenomena. which have a negative impact on the state of the environment, the technical infrastructure and the property of citizens. They are determined both by natural factors (geological structure prone to landslide activity, intense tectonics, groundwater, erosion, etc.). as well as anthropogenic factors such as illegal construction in risky areas, intensifying urbanization processes in a certain territory, illegal logging, etc.

They are natural phenomena, in which the stability of huge amounts of gem masses is disturbed and prerequisites are created for their movement. Landslide processes are not sudden in nature and are available for intervention. In time, they have periods of attenuation and amplification. After the activation of the earth masses, a disaster situation may occur. Over 200,000 acres of the territory of our country are affected by about 1,000 landslides. The reasons for their occurrence are related to the highly rugged terrain and other specific geological features in certain areas.

Landslide processes are not evenly distributed over the entire territory of the country. They are concentrated in separate areas, characterized by a specific geological and tectonic structure, and are separated into several landslide areas:

Black Sea landslide area. Main factors for the occurrence of landslides in this area are sea abrasion. the rise of underground water levels in urbanized areas, high rainfall waves and seismic events in the Shablen earthquake zone. In the areas located along the Black Sea coast, 121 units were registered. landslides. which represents 13% of their total number in the country. In the Varna and Dobrichka regions, 80% of the landslides are along the coast. A significant part of them are periodically activated as a result of both natural factors. as well as anthropogenic intervention. The highest percentage of active landslides is in the Varna region - 31 pieces. or 56% of all active landslides along the Black Sea coast. The number of stabilized landslides along the Black Sea coast is 38, which is 18% of all stabilized landslides in the country.

Danube landslide area. Landslides are tied to the high Danube bank. The main factor for their occurrence and periodic activation is river erosion. The areas located on the right bank of the Danube are most affected by landslide processes. 369 units were registered in these areas. landslides, which represents 40% of the total number of landslides registered in the country. The largest number of landslides were registered in the Pleven region - 156. Of them, 112 pcs. are active, and only 2 landslides are registered as stabilized.

Pre-Balkan landslide area. The strip between Etropole and Targovishte is highly active. In the last few years, landslides have been active in the areas of Troyan, Sevlievo. Veliko Tarnovo. A guard. Antonovo and Targovishte. The main activating factor is the rise in groundwater levels, river erosion and man-made impacts.

The districts covering parts of the Pre-Balkans are affected by 256 pcs. landslides. They are relatively shallow and with a significantly smaller volume than the landslides along the Danube and Black Sea coasts. They are mainly caused by river erosion and anthropogenic activity (undercutting of steep slopes, their overloading with embankments, rise in groundwater levels). Active landslides in these areas are 158 or 62%, 39 are stabilized, which makes 15% of the registered landslides.

Sub-Balkan landslide area. The sub-Balkan landslide area includes the valley fields of Zlatitsa-Pirdop, Karlovo, Kazanlak and Sliven. Landslides are localized in the fence slopes of the hollows. Main factors are underground water and technogenic activity.

Sofia landslide area. The Sofia landslide area is mainly developed along the periphery of the valley (Bankya, Ivanyane, Gorna Banya, Knyazhevo, Boyana, Dragalevtsi, Simeonovo, Bistritsa, Pancharevo, Kokalyane, Lozen, Gnilyane, Novi Iskar, Dragovishtitsa, Bozhurishte), but landslides are not rare either in its central part (Lozenets, Zapaden Park, Zemlane, and Vartopo).

Southwest landslide area. The southwestern landslide area includes areas from Pernishka, Kyustendilska, and Blagoevgrad regions. Landslides have developed along the fence slopes in the Pernik areas. Bobov dol, Blagoevgrad and Simitli.

Rhodope landslide area. The Rhodope landslide area includes the occurring landslides in the areas of Smolyan. We shout and General Geshevo.

6.2 Actions in case of activated landslides.

In case of activated landslides, reconnaissance is carried out to establish:

1. the size and boundaries of the affected area;

2. the state of the constructed drainage facilities: ditches, canals, culverts, drainage shafts, open drains, etc.;

3. the technogenic factors that caused the landslide process - an accident on the water supply networks, excavation and construction activities, etc.;

4. the condition of the elements of the technical infrastructure in the area of the landslide;

5. the condition of the building stock in the area, dangers to the lives of the residents.

 

Based on the intelligence data, the on-site leader assesses the situation, specifies the capabilities of the available forces and the need to attract additional forces and funds, assigns tasks to the teams and determines the order for conducting the NAVR.

When carrying out the NAVR, the on-site manager takes the following measures, depending on the manifested landslide process - initial stage or full activation:

1. marking and signaling the dangerous section;

2. changing the traffic order in the area of the landslide until the arrival of the competent authorities;

3. organization of temporary security of the area and preventing the passage of people;

4. not allowing activities in the area that create vibrations in the soil (from heavy mechanization and transport);

5. for the clearing of streets and roads, organize the seizure of small amounts of the collapsed earth masses in order to avoid a sudden landslide of the massif; when using specialized equipment, only drivers of machines with the necessary qualifications are allowed;

6. not allowing the deposition of earth masses, construction and other waste above the main landslide slope;

7. not allowing excavation works undermining the base of the slope in the activated landslide area;

8. if there is a broken water pipe in the area of the landslide, notify the relevant operator through the OC about the interruption of the water supply in the area of the landslide;

9. in the presence of poles of overhead electric wires, notifies the relevant operator through the OC about the interruption of the electricity supply in the area;

10. in the case of uncovered routes of underground wires, notifies the relevant operator through the OC to undertake the strengthening or displacement of the wires along safe routes;

11. temporary removal of people from the threatened buildings if necessary;

12. organizes monitoring of the activated landslide massif and requires the competent structures (the local self-government bodies and the structures of "Geoprotection" - EOOD) to place markers, build reference networks.

 

According to instructions/prescriptions given by experts specified in the disaster protection plans, the NAVR coordinates:

1. removal of surface and other slope waters from the body of the landslide massif by:

a) construction of temporary bypass-drainage ditches above the main landslide slope to drain unregulated surface runoff and other slope waters outside the area of the landslide body;

b) damming of river currents;

c) lowering the level of groundwater through emergency water extraction through existing or newly constructed boreholes;

d) draining, if necessary, the existing reservoirs in the body of the landslide massif or nearby by digging drainage channels and ditches;

2. execution of the most urgent strengthening works on retaining walls, paving of sections, arrangement of concrete blocks, etc.;

3. mechanical removal of soil layers to relieve the load on the sliding earth masses;

4. other measures according to the specific situation.

6. High winds, storms and tornadoes

Tornadoes are not so common, but are a familiar natural phenomenon for some areas of the country. It is an atmospheric vortex that moves at tremendous speed. Occurs in storm clouds. near the earth's surface, its lower part resembles an inverted funnel. It leads to destruction, human casualties are possible.

Strong winds are a frequent phenomenon in the territory of the country, in some cases, with a particularly high speed of the air masses. poses a danger to humans

 

7. Actions in high winds, storms and tornadoes

In case of strong winds, storms and tornadoes, reconnaissance is carried out to determine:

1. the size and boundaries of the affected area;

2. the degree and nature of the destruction;

3. difficulties and violations in transport communications;

4. the condition of the networks and facilities of the technical infrastructure in the area;

5. difficulties in supplying the population in the affected areas with essential goods, medical and other insurance;

6. the need to attract forces and means to conduct the NAVR in the affected area;

7. places to provide shelter to the affected population and to distribute food, water, medicines, etc.

Based on the data from the conducted reconnaissance, the on-site manager assesses the situation and determines:

1. the measures that should be taken depending on the specific situation;

2. the teams, equipment and technique necessary to conduct the NAVR, and assigns them tasks;

3. the procedure for conducting NAVR and organizes compliance with safe working conditions;

4. the need to attract specialized teams to provide medical and psychological assistance.

 

EARTHQUAKES

 

In the seismically active regions of the planet, including Bulgaria, earthquakes appear as the most catastrophic natural disasters. The observed trend of increasing damage from earthquakes is explained by three main factors:

• a large increase in human and material losses in strongly earthquake-prone areas;

• underestimation of the real earthquake danger, leading to the belittling and even elimination of anti-earthquake measures, above all in construction;

• still insufficient opportunities for science to offer highly effective solutions to reduce the consequences by predicting earthquakes and the characteristics of expected strong earthquake impacts and to offer absolutely safe methods for securing construction.

Earthquakes are not evenly and randomly distributed over its entire surface. They are concentrated in seismic belts that coincide with the zones of contact and relative movements between the large lithospheric plates. Bulgaria is located in the eastern part of the Balkan Peninsula, which is the most active node of the Alpo-Himalayan belt for Europe.

The earthquake situation in the Balkans has its own specificity. The main part of the earthquakes are shallow with foci at a depth of up to 60 km (in the earth's crust), which greatly increases the effects on the earth's surface. With high population density and high building density, this fact means significant consequences even from relatively weak earthquakes.

Earthquakes are natural disasters with the highest risk, which can cause landslides, floods, accidents, epidemics, disruption of communication and transport links, etc. The most severe situation is usually created in densely populated and industrial areas of large cities.

These consequences depend on the magnitude of the earthquake, on the distance of the objects from the epicenter and on the safety of the buildings against seismic impacts.

Seismic securing of buildings and facilities in Bulgaria remains the decisive factor for reducing human and material losses in the event of an earthquake. Over the years it has been regulated as follows:

• until the beginning of 1958, buildings (including those with different categories of Bulgarian cultural heritage on the territory of the country) were not insured against earthquake impacts;

• 1957 - the "regulations for the design and construction of buildings and engineering facilities in seismic areas" came into force, based on a seismostatistic map of zoning, reflecting the observed intensities (magnitudes) of the earthquakes documented until then;

• In 1961 and 1964, the map was reassessed, underestimating the areas of the VII, VIII and IX degree zones;

• 1977 - after the earthquake in Vrancha, new areas of VII and VIII degrees were added in the Danube part of northern Bulgaria;

• 1987 – a new seismic zoning of Bulgaria was introduced;

In general, 98% of the territory of Bulgaria will be subjected to seismic impact with intensity of 7th degree and higher, of which with intensity of 7th degree - 51%, with 8th degree - 28%, with 9 degree and higher - 19%. These areas include settlements with a population of about 6,340,000 people, representing 80% of the country's population, and may be partially or completely destroyed - 26% of the building stock. About 5,900,000 people, which is 74% of the country's population, fall into areas with intensity of the 8th and 9th degrees on the MSK-64 scale.

fig.1 Seismic zoning of Bulgaria

 

In preparing our country to meet a strong earthquake, the most serious problem related to vulnerability is the available building stock, a very large percentage of which was designed and built before the new earthquake norms of 1987, i.e. for much lower levels of seismic insurance. Data on the strongest earthquakes in the 20th century, whose epicenters are on the territory of Bulgaria, are shown in table 2.

 

 

A specific problem is the lack of undertaken and implemented preliminary strengthening measures for the protection of discovered, preserved and restored archaeological structures, buildings and ensembles of national importance, vaults and storage facilities for storing movable cultural values from the impact of risk factors. The possibility of mobilizing, if necessary, expert teams to assess the damage to the building stock, as well as the way of providing the affected population with temporary shelters, especially in adverse weather conditions, remains unclear.

The problem is the condition of the building stock of enterprises with risky productions. There are still bad practices in spatial planning, investment design and the implementation and operation of constructions, leading to an increase in the risk of destruction in the event of a seismic impact. Such bad practices are:

• inconsistent routes of the road and engineering infrastructure in the development schemes;

• lack of planned planning, design and implementation of integrated measures in the investment projects, which are also disaster protection measures;

• inconsistent indicators of density and intensity of construction;

• allowing reduced (relatively small) distances between buildings;

• continued, although to a lesser extent, remodeling in the ground floors of existing buildings, leading to a serious increase in the vulnerability of the structures.

There is a lack of vision for the responsibilities for determining and complying with the minimum requirements for the degree of resilience of the country's critical infrastructure in terms of seismic impact. Earthquake levels have not been defined at which, as a result of already destroyed building stock and facilities, we expect serious damage to power transmission and power distribution facilities.

Many of the institutions do not have data on the degree of sustainability of the buildings and facilities in the sphere regulated and managed by them.

No work is being done to limit the degradation of the existing building stock.

 

8.     Activity for NAVR in the event of an earthquake.

 

In case of an earthquake, in which there is a combined zone of defeat - destruction, burials, people under the rubble, destruction of elements of the utility-energy network, fires, pollution with industrial toxic substances, creation of foci of pollution from radioactive sources, floods, activation of landslides , disruption of communications, a large number of affected people and those left without homes, the possibility of biological contamination, creation of prerequisites for the emergence of epidemics and others, the NAVR is conducted.

In the area affected by an earthquake, emergency response is carried out in cooperation with the main components of the unified rescue system.

Reconnaissance is conducted to determine:

• travel routes to the defeat zone.

• the places for setting up side and highway passages.

• the locations of buildings with mass residence of people and those in which search and rescue operations must immediately begin.

• the degree of destruction of the elements of the utility-energy networks (KEM) and the secondary damage they caused.

• outbreaks of fires.

• the presence of contamination with radioactive sources, POPs, agents of biological contamination.

• the buildings threatened with demolition, which are not subject to strengthening.

• the presence of concentrations of explosive and flammable gases in the air above the permissible values.

• the condition of roads and road facilities.

• the state of hydrotechnical facilities.

• the condition of tailings ponds.

• the state of the railway network, airports and ports.

• the places convenient for deploying VPSP.

• suitable places to store the bodies of the dead.

• the locations of helipads.

• places to set up tent camps.

• the places for deploying camping kitchens.

• points for distribution of food, water, medicine and others.

• the deployment locations of field hospitals.

• the extent and nature of the destruction.

• the presence of living people under the ruins.

• the possibility of using different types of means of communication.

• locations convenient for deploying control points (CPs).

• the discovery of designs, schemes, drawings or other similar information about the destroyed buildings.

• survivors who can provide useful information.

• the state of the epidemiological situation.

• the convenient locations for deploying checkpoints to and from the area of defeat.

• the presence of social institutions that could function and perform tasks to eliminate the consequences.

• the presence of objects that must be immediately secured.

• the condition of embassies and buildings where foreigners reside.

• the state of objects that could cause ecological pollution of the environment.

• the state of social institutions for the residence of people with mental disabilities, adults, children deprived of parental care, places of deprivation of liberty.

• the state of objects of national importance.

Based on the data from the intelligence conducted, the on-site manager assesses the situation, assigns tasks to the teams, determines the procedure for conducting the NAVR and organizes the observance of safe working conditions.

When conducting the NAVR, the on-site manager undertakes the following:

• 1. notifies the electricity distribution company through the OC of the disconnection of the electricity supply in the area;

• 2. notifies the operators through the OC of interruption of the water supply and product pipelines for liquid or gaseous substances;

• 3. organizes the implementation of urgent strengthening works in buildings and facilities in the places of intervention;

• 4. organizes the provision of access of mechanized means and equipment to the affected areas;

• 5. organizes the execution of fire extinguishing actions;

• 6. organizes emergency drainage of endangered areas;

• 7. organizes the fumigation of smoky premises;

• 8. organizes the taking of preventive measures to reduce the risk of secondary harmful consequences;

• 9. organizes, if necessary, the dispersal of belongings and valuables;

• 10. assists in organizing tent camps for the affected population;

• 11. assists other emergency recovery teams from ESS;

• 12. coordinates the clearing of destruction;

• 13. organizes the provision of assistance in the implementation of the NAVR in water management facilities according to the emergency plans.

 

The NAVR department participates in intelligence when assigning tasks from the operational communication and information centers. When carrying out such reconnaissance, O "ASD" uses its own means of communication.

With the help of the bodies of the Ministry of Internal Affairs, no persons not related to the rescue activities are allowed in the site of the NAVR.

Based on the intelligence data, the on-site manager assesses the situation, assigns tasks to the groups and determines the order of work, and instructs on the measures for safe working conditions.

Rescue operations begin with urgent strengthening works in half-destroyed and burning buildings and facilities with the aim of evacuating people and finding and rescuing those buried under the ruins.

When conducting the NAVR, if possible, the plans of the buildings and facilities are used or persons who live or

The clearing of the destruction is done from top to bottom, and the technique is not introduced on the destruction and no direct clearing is carried out with it.

Passages are being built under the debris to save people

When making the passages, the obtained shape of the destruction should be preserved as much as possible, and where it is necessary to expand or drill holes, the necessary precautions should be taken to avoid injury to the victims and to strengthen the structure. It is also possible to arrange vertical shafts to reach the buried ones.

The strengthening of structures is most often carried out with auxiliary materials (wooden material, etc.). If the victim is near the outer edge of the embankment, it is possible to use air-lifting cushions for temporary reinforcement. This method is applied to relatively strong structures and resistance to destruction and the absence of repeated earthquakes of great intensity.

In case of danger of secondary earthquakes and destroyed unstable structures, preventing the construction of passages and shafts, SNAVR is carried out by successive clearing, with the main attention to the places with localized people.

Geophones, thermal cameras, sonars and rescue dogs are used to search for people under ruins.

Periodically, all activities and work with machines are suspended to detect signals given by overwhelmed people.

After discovering the buried person, contact is established with him to clarify his exact location, his state of health and the situation around him. This information is necessary for the preparation of the rescue team for carrying out the rescue activities.

The trapped person must understand clearly and emphatically that he has been found and that rescue teams are working to save him. Contact with the victim is periodically maintained in order to save his strength. If necessary, it is supplied with air.

When discovering trapped people, it is possible to carry out rescue operations by hand without the use of mechanization. This is most often done in the case of monolithic construction and close proximity to the victim.

During the rescue operations, elements that have not been released are not forcibly separated, nor are cables, ropes, pieces of fittings, etc. pulled.

When working with means for small mechanization, for the construction of passages and shafts, the measures for safe working conditions in case of gas poisoning are observed and the sanitary-hygienic and anti-epidemic measures are observed with the rescuers.

The use of assigned heavy engineering equipment (bulldozers, excavators, cranes, cranes, etc.) is directed by the site manager or a person authorized by him.

Setting up passages in the debris and rescuing victims from buried buildings and facilities

Clearing the debris and creating passages is an important task of the engineering formations involved in the rescue operation.

The peculiarity of these works lies in the fact that they must be carried out in the shortest possible time in order to ensure the timely access of the rescue formations to the work sites and to quickly provide assistance to the victims. The work ends with placing signs and traffic regulation posts.

If there is a river, canals and other water barriers in the settlement, preventing the passage of the rescue formations in the focus of defeat, it is necessary to build a ford or build temporary bridges (simplified construction).

In the course of the rescue operation, the primary task is the rescue of the buried and those whose lives are threatened by the impact of secondary factors. Those buildings and facilities from which those taking refuge cannot get out on their own are considered to be overwhelmed. Usually, the congestion of the exits is at a height of more than 0.5 t.

The search for the victims is carried out by the emergency and rescue units, which meticulously inspect the territory of their designated area for work.

Extracting the victims from under the rubble is an extremely complex and difficult activity. In order to determine the most appropriate course of action, it is necessary to carefully inspect and study the rubble, while at the same time taking measures to prevent further collapses.

The rescue of victims from the overwhelmed buildings and facilities is carried out as follows:

- the locations of the overwhelmed buildings (facilities) of

territory of the city (site);

a connection is established with the hidden and the situation is clarified;

- the supply of air to the cluttered or destroyed room (facility) is ensured, if this is necessary;

- passages are made to the crowded hiding places and the places for deploying the means of mechanization are cleared;

- opening of the cluttered room is carried out;

those in the facility are provided with an exit, and those affected are given first medical aid and evacuated to the medical center;

the exposed premises (facilities) are indicated by conventional signs.

The discovery of the flooded shelters in the focus of defeat is done by local objects, with the help of stored plans and by means of specific signs.

The hiders can be contacted by phone or radio if they are saved. In case of impossibility to conduct a conversation on

the phone and the radio can be used! ventilation pipes and other openings. In addition, a connection can also be established by tapping.

To supply air to the victims, first of all the preserved ventilation pipes and devices are discovered and cleared. When these devices are destroyed, efforts are directed to clearing and opening the doors of the premises (facilities) or the roof of the emergency exits or an opening is drilled in the enclosing structures.

Air supply to the room is carried out with the help of compressors, portable fans or through the holes made,

The victims located near the surface of the ruins. are taken out after carefully clearing the structural elements and other objects that prevent their rescue. and for the rescue of those buried in the lower floors and basements of the destroyed and badly damaged buildings, passages and openings with a width of 0.6-0.8 m and a height of 0.9-1.1 m are arranged. The victims are carried out in different ways depending on the conditions: on hands, on cloths, blankets, stretchers, etc.

Casualties located in the depth of the pile-up (below the pile-up). are extracted through passages with dimensions: width 0.6-0.7 m and height 0.6-0.9 m.

The gaps and cracks formed in the backfill from the fall of large building elements are used to arrange passages.

The victims are extracted from under the rubble by calculations formed by the units of the rescue formations. Each estimate consists of 4-6 people, one of whom is appointed as a senior.

To rescue people from buildings with destroyed or blocked entrances, resort to clearing the blocked entrances; drilling holes in the walls to connect with the rooms that have an exit; use of different types of ladders, ropes, abseils; containment and extinguishing of fires obstructing entrances and exits of buildings.

The opening of the emergency exits is carried out with the help of bulldozers, excavators, etc. engineering machines. Excavators or cranes are used to clear the building entrances and make passages to the enclosing structures.

STRENGTHENING AND DEMOLITION OF BUILDING STRUCTURES

Threatening to collapse, is required to ensure the safety of formations in the focus of defeat.

Before starting work, it is necessary to review the unstable buildings and structures and determine which of them need strengthening and which are for demolition. The next activity is to cordon off (isolate) the buildings designated for demolition to prevent accidents.

The strengthening of the buildings, depending on their heights, is carried out in the following way: walls with a height of up to 6 tons are strengthened by placing ordinary wooden or metal supports.

Walls of buildings with a height of 12 m and more are strengthened with double supports. In both cases, the number of supports is determined by the stability of the building being strengthened. Elements from destroyed buildings and structures can be used for strengthening.

The demolition of the buildings threatened with collapse is carried out with the help of a tractor, a winch and a metal rope.