World earthquake science knowledge 10 questions

1. What is the depth of the source?

A: The depth of an earthquake refers to the distance from the point where the earthquake originates (the focus) to the Earth's surface. Earthquakes with depths less than 60 km are classified as shallow, while those deeper than 300 km are considered deep. In between, earthquakes with depths between 60 and 300 km are called intermediate. Shallow earthquakes tend to cause more damage because the energy released is closer to the surface. Most earthquakes in China are shallow, which makes them more likely to impact human life directly.

2. What is the periodicity of seismic activity?

A: Seismic activity does not occur evenly over time. There are periods when many large earthquakes happen, known as active periods, and times when fewer, smaller earthquakes occur, referred to as quiet periods. These cycles can last for decades or even hundreds of years. During active periods, major earthquakes of magnitude 7 or higher may occur multiple times. Different regions have different seismic cycles, making it important to monitor local patterns for better preparedness.

3. What is the intensity of earthquakes and how does it differ from magnitude?

A: Earthquake magnitude measures the total energy released during an earthquake, while intensity describes the effects felt at a particular location. Magnitude is a single value for each earthquake, but intensity varies depending on the distance from the epicenter and local conditions. For example, the Tangshan earthquake of 1976 had a magnitude of 7.8, but the intensity was highest near the epicenter, reaching level XI, and decreased with distance.

4. What is the technical standard for assessing earthquake intensity in China?

A: China uses the "China Earthquake Intensity Scale (1980)" to assess earthquake intensity, which divides the scale into 12 degrees. Degrees I to V are based on people’s feelings, VI to X consider building damage, and XI and XII indicate severe destruction. Generally, lower intensities cause no damage, while higher ones lead to significant harm. Understanding these levels helps in disaster response and planning.

5. Why is the epidemic after the earthquake easily popular?

A: After a strong earthquake, water supplies and sanitation systems are often damaged, leading to poor living conditions that increase the risk of disease outbreaks. Historical examples show that many deaths after earthquakes were due to disease rather than the quake itself. However, modern public health efforts have significantly reduced this risk, as seen in the 1976 Tangshan earthquake, where no major epidemics occurred despite the devastation.

6. Can the earthquake forecast?

A: Earthquake forecasting remains a complex scientific challenge. While some progress has been made, especially in identifying certain precursor signals, short-term predictions are still unreliable. China has developed some methods for medium- and long-term forecasts, but predicting exact timing and location of an earthquake is still not possible. Research continues to improve accuracy and reliability.

7. What is earthquake rumor?

A: Earthquake rumors are unverified claims about impending earthquakes that circulate in society. These can be misleading and cause unnecessary panic. Common causes include misinterpretation of natural phenomena, misunderstandings of scientific activities, or deliberate misinformation. It is important to rely on official sources and avoid spreading unconfirmed information.

The specific reasons for the occurrence of earthquake rumors include: Misinterpreting natural events like animal behavior or weather changes as signs of an earthquake. Some people may also believe in myths or superstitions, or be influenced by foreign media or individuals with ulterior motives.

8. How is the earthquake microscopic precursor observed?

A: Scientists use various instruments to detect subtle changes before an earthquake. These include seismographs for small tremors, inclinometers and extensometers for crustal deformation, magnetometers for magnetic field changes, and sensors for groundwater and soil pressure. These tools help scientists gather data to better understand earthquake processes.

9. What are the manifestations of abnormal animal behavior?

A: Animals often behave strangely before an earthquake. Common signs include restlessness, unusual aggression, or sudden flight. For example, birds might fly erratically, snakes may leave their burrows, and dogs may bark excessively. While these behaviors can sometimes indicate an upcoming earthquake, they are not always reliable, as other factors can also affect animal behavior.

10. Are animal behavior abnormalities related to earthquakes?

A: Not always. Many factors can cause animals to behave abnormally, such as changes in weather, illness, or environmental stress. It is important not to panic if you notice unusual behavior in animals. Instead, report your observations to local authorities for proper evaluation and guidance.