Natural Hazards and Disasters

Shifting cultivation (also called slash-and-burn) is primarily practiced in tropical regions with fertile soil and adequate rainfall - including tropical Africa, Southeast Asia, and the Amazon basin in South America. These regions have the climate conditions that allow for forest regrowth after cultivation cycles.

Statement 1 is incorrect because shocks originate at the hypocenter (focus), not the epicenter. The epicenter is the point on the surface directly above the hypocenter. Statement 2 is correct - earthquake foci can be in the crust or upper mantle. Statement 3 is correct - plate margins are indeed more earthquake-prone.

The cultivation is done on the steep slopes so that the water should not remain stagnant and no soil erosion would be there.

Volcanoes release various materials during eruptions, including molten lava, gases, steam, dust, and rock fragments. Different eruptions may produce different combinations of these materials, so 'all of the above' is the most comprehensive answer.

Statement 1 is correct - moderate earthquakes do occur along constructive plate boundaries. Statement 3 is correct - disastrous earthquakes are typically caused along destructive (convergent) plate boundaries. Statements 2 and 4 are incorrect as they don't accurately describe the relationship between plate boundary types and earthquake severity.

Magma is called lava when it reaches the Earth's surface (crust). Magma is the molten rock beneath the surface, while lava is the same material once it erupts and flows on the surface. The core and inner portion are too deep, and mantle is where magma originates.

Lahar is a geological term for a destructive mudflow or debris flow composed of pyroclastic material, water, and rock fragments that flows down the slopes of a volcano (typically stratovolcanoes) and down river valleys. Lahars are often triggered by heavy rainfall, volcanic activity, or the sudden melting of snow and ice near a volcano's summit during an eruption. They can travel long distances at high speeds, causing significant destruction.

The largest tsunami ever produced by a landslide was in Lituya Bay, Alaska in 1958. (Taken from NCERT, Class XI)

Deep focus earthquakes are rarely destructive because by the time the waves reach the surface, the impact reduces. Shallow focus earthquakes are more common and are extremely damaging because of their proximity to the surface.

There are different types of floods, namely flash floods, riverine floods, urban floods, etc. Flash floods can be defined as the floods which occur within six hours of the beginning of heavy rainfall and are usually associated with cloud bursts, storms and cyclones requiring rapid localised warnings and immediate response to reduce damage. Wireless network and telephone connections are used to monitor flood conditions. In case of flash floods, warnings for timely evacuation may not always be possible.

S waves (shear waves) can only propagate through solids because they require the medium to resist shear stress. Liquids cannot support shear stress, so S waves cannot travel through them. This is why S waves cannot pass through Earth's liquid outer core. The statement 'S waves propagate through liquids' is incorrect, which is exactly what the question asks for (which statement is NOT correct).

The circum Pacific belt (Ring of Fire) is primarily located along convergent plate boundaries where plates collide, creating intense seismic and volcanic activity. These convergent boundaries involve subduction zones, volcanic eruptions, and frequent earthquakes. Divergent boundaries create new crust and are associated with different geological features, not the Ring of Fire.

The definition of severe drought conditions is based on rainfall deficiency percentages. According to meteorological standards, when annual rainfall deficiency exceeds 50% of normal (long-term average), the region is considered to be experiencing severe drought. Options A and B represent moderate deficiency levels, while option D (70%+) would represent extreme drought.

Poland has experienced the most severe forest damage from acid rain in Europe, particularly in the Sudeten Mountains and Krkonose regions. Heavy industrialization combined with high sulfur dioxide emissions from coal burning, combined with geographical factors that trap pollutants, caused extensive forest dieback in Poland - more than Italy, Spain, or most other European countries.

Oil spill is classified under 'Chemical, industrial or nuclear hazards'.