Knowledge Points
- Distribution of volcanoes and seismic zones
Earth Lithosphere can be divided into Six major plates : Asia and Europe plate, Africa plate, Indian Ocean plate , Pacific plate, Antarctica plate, and America plate. Between two adjacent plates, two boundaries of are formed:
① growth boundary : The two plates are far away from from each other, and the distance is getting farther and farther away, and often form ridges, faults, rifts, and new oceans (red boundaries in the figure below).
② dying boundary : Two plates squeeze against each other, getting closer and closer, often forming mountains and trenches (green boundary in the picture below).
Figure 1 Distribution of the six major plates
On the growth and extinction boundaries, volcanic earthquake zone is often developed. The two major volcanic seismic zones in the world are: Pacific Rim Volcanic Seismic Zone , Mediterranean - Himalayas volcanic seismic zone .
Figure 2 Distribution of major volcanoes and seismic zones in the world
Example
The following figure shows the distribution of earthquake focal depth in Japan and its nearby waters. Read the picture and answer questions 9 to 10.
9. The distribution characteristics of the seismic depth in Japan and its nearby seas are ( )
A. From north to south, the depth increases
B. From south to north, the depth increases
C. From west to east, the depth increases
D. From east to west, the depth increases
10. On March 11, 2011, a magnitude 9 earthquake occurred in the sea east of Japan, and Fukushima Nuclear Power Plant was damaged. The leaked pollutants spread with ocean currents. The main direction of diffusion is ( )
A. Southwest
B. Northwest
C. Southeast
D. Northeast
Answer: D. D
Exquisite analysis: (1) Analyze the distribution of the depth of the earthquake focal point. ① From the figure, it can be seen that from east to west, it is shallow source earthquake, middle source earthquake, and deep source earthquake, that is, the depth of the earthquake source gradually increases, option D is correct; ② This is mainly due to the Pacific plate, from east to west, subduction below the Asia-European plate. Therefore, the further away from the plate junction (west), the deeper the Pacific plate subduction, that is, the deeper the source of the earthquake.
(2) Analyze the direction of pollutant diffusion. ① The coast of the Fukushima nuclear power plant is Japanese warm current , with a flow direction roughly from southwest to northeast; ② Therefore, the pollutants leaked from the nuclear power plant flow roughly in the northeast along with the ocean current, and option D is correct.
Summary of
- The impact of ocean currents
The example questions in this section are less difficult, and the solution ideas for are: ①Analyze the changes in the depth of the earthquake source according to the distribution of shallow, middle and deep sources in the figure; ②Analyze the diffusion direction of pollutants according to the flow direction of ocean currents.
ocean currents are divided into warm currents and cold currents according to their properties. The impacts of ocean currents on climate, navigation, pollution and fishery distribution are:
① Climate : Warm current " Increase warming and humidification ", cold current " Cooling and dehumidification ";
② Navigation : a) Following the ocean current will save fuel , and counter-current will increase fuel consumption; b) When the cold current meets the warm current, it will produce sea fog , affecting navigation ;c) Ocean currents will carry sea ice from the Arctic region, affecting the navigation safety of ships;
③ pollution : Ocean pollution will spread everywhere along with the ocean currents ;
④ fishing ground : The intersection of cold currents and warm currents, offshore currents will bring a large amount of nutrients, providing sufficient bait for fish, which is conducive to the formation of fishing grounds .
Figure 3 Distribution of world currents
[20:00 every night, one question every day, learn geography well]
