Đề ôn thi Đề thi tốt nghiệp THPT môn Tiếng Anh - Mã đề THPT-129

Earthquakes, (18) __________, are powerful geological events that can reshape landscapes and leave lasting impacts on human societies. (19) __________. The point of origin for these waves, typically located deep within the Earth, is called the hypocenter, while the point on the surface directly above it is known as the epicenter.

The intensity of earthquakes is measured using the Richter scale, a logarithmic scale where each whole number increase represents a tenfold increase in wave amplitude and approximately 31.6 times more energy release. For instance, a magnitude 6.0 earthquake releases about 31.6 times more energy than a magnitude 5.0 earthquake. One of the most powerful earthquakes ever recorded, (20) __________, occurred in Valdivia, Chile in 1960. This devastating event caused widespread destruction, triggering tsunamis that reached across the Pacific Ocean.

While the majority of earthquakes occur along tectonic plate boundaries, (21) __________, they can also be triggered by volcanic activity, human-induced activities like mining or geothermal energy extraction, and even large landslides. Regardless of their cause, earthquakes serve as a powerful reminder of the immense forces constantly at work beneath our feet.

(22) __________, early warning systems, and public education programs. By studying these events, scientists can better understand the Earth's dynamic processes and help societies become more resilient to their impacts.

Global migration, the movement of people across international borders for various reasons, is a complex phenomenon shaped by a multitude of factors. These factors include economic disparities between nations, political instability and conflict, environmental changes, and the pursuit of better education and opportunities. For instance, the allure of higher wages and improved living standards in developed countries often drives individuals from developing nations to seek employment abroad. Simultaneously, political persecution or armed conflict can force people to flee their home countries in search of safety and refuge.

The impacts of global migration are far-reaching and multifaceted, affecting both sending and receiving countries. This intricate interplay of influences generates a constant flow of people across the globe. One significant consequence is the economic impact on both nations involved. Migrant workers often send remittances, or portions of their earnings, back to their families in their home countries, boosting local economies. At the same time, they contribute to the workforce and tax base of their destination countries.

However, migration also presents challenges. Receiving countries may face strains on social welfare systems, housing, and infrastructure as they strive to accommodate newcomers. Integrating migrants culturally and linguistically can also be demanding, and sometimes leads to social tensions. Meanwhile, sending countries might experience brain drain, a loss of skilled workers who could contribute to their home country's development.

Despite these difficulties, global migration offers transformative opportunities. It fosters cultural exchange, promotes diversity, and enriches societies through the sharing of knowledge, skills, and perspectives. Recognizing the complex dynamics of global migration is crucial for policymakers, communities, and individuals to navigate the challenges and harness the benefits of this global phenomenon.

Understanding the Earth's dynamic nature requires delving into the theory of plate tectonics. [I] This theory explains the large-scale motion of Earth's lithosphere, which is broken into several pieces called tectonic plates. [II] These interactions give rise to phenomena such as earthquakes, volcanic eruptions, and the formation of mountain ranges. [III] The movement of these plates, though incredibly slow, averaging a few centimeters per year, has dramatically reshaped the Earth's surface over millions of years, contributing to the continents' current locations. [IV]

The driving force behind this continuous movement is heat convection within the Earth's mantle. This process, similar to boiling water in a pot, involves the hotter, less dense material rising and the cooler, denser material sinking. This creates currents that drag the tectonic plates along with them. The boundaries where these plates meet are particularly active zones. For instance, the Pacific Ring of Fire, a horseshoe-shaped zone encircling the Pacific Ocean, is known for its high concentration of volcanoes and earthquakes, a direct consequence of plate interactions.

Different types of plate boundaries result in various geological events. At divergent boundaries, plates move apart, allowing magma from the mantle to rise and create new crust. This process is evident in the mid-Atlantic ridge, a vast underwater mountain range formed by sea-floor spreading. Conversely, at convergent boundaries, plates collide, leading to subduction, where one plate slides beneath another, often causing earthquakes and volcanic activity. The Himalayas, the world's highest mountain range, are a dramatic example of continental collision, formed by the convergence of the Indian and Eurasian plates.

Finally, at transform boundaries, plates slide past each other horizontally. This type of movement often generates powerful earthquakes, as seen along the San Andreas Fault in California. The continuous interplay of these different plate boundary interactions demonstrates the dynamic nature of our planet, constantly reshaping its surface and influencing the distribution of landmasses and oceans throughout geological time.