Earthquakes — Shapers of the Earth's Face

Hey everyone, it's me, the famous earthquake! I know people around the world dislike me. When I suddenly appear, the Earth's crust starts shaking up and down, left and right, resulting in a once-beautiful landscape becoming pitted and uneven, with hills and valleys, and a completely altered appearance. I am, in a way, a shaper of the Earth's face. In truth, I don't want to show up so often; it's all because of my master, the Earth's magma, which enjoys boiling and moving wildly. Of course, my master is mostly calm, and many times when I visit the surface, I go unnoticed and don't cause any destructive results like collapsed buildings. But I do cause the Earth's crust to slowly drift and change the original landscape, which takes thousands of years or even longer for humans to discover, such as majestic mountains, vast oceans, and expansive plateaus. These are all my masterpieces, ha ha. Well, now I'll introduce to you all the details of my origin.

When the Earth's crustal rock layers are rapidly broken and displaced due to stress, causing vibrations or damage to the surface, I appear. Our family has three brothers: the eldest is caused by tectonic activity, known as a tectonic earthquake; the second is caused by volcanic activity, known as a volcanic earthquake; and the third is caused by the collapse of solid rock layers, known as a collapse earthquake. Our existence is a very common and ordinary natural phenomenon, but due to the complexity of the Earth's crust structure and the inaccessibility of the seismic source area, the mechanism of how tectonic earthquakes are conceived and occur remains a mystery. However, scientists generally agree that tectonic earthquakes are caused by the movement of the Earth's crustal plates. The place where we first occur is called the focus, and the ground directly above the focus is called the epicenter. The area where our shaking is the strongest is called the meizoseismal area, which is essentially the central area of our intense activity. After we appear, we often cause severe casualties to humans and can also lead to fires, floods, toxic gas leaks, and the spread of bacteria and radioactive materials. In addition, we can cause secondary disasters such as tsunamis, landslides, collapses, and ground fissures.

Our three brothers are on duty over 5 million times a year, which is tens of thousands of times a day. Most of the time, we are well-behaved and don't throw tantrums, and humans can't even feel our presence. But occasionally, we get out of control and start jumping around wildly, about once or twice a year. After we calm down, we realize that our uncontrolled movements have caused serious consequences for humans, and sometimes even catastrophic disasters. We regret our actions. On behalf of us three brothers, we apologize to everyone.

Humans are very smart and have installed various listening instruments on the Earth's surface to capture our movements. Different types of listening devices can record earthquakes of different strengths and distances. There are thousands of seismic listening instruments operating around the world, monitoring our movements day and night, and gradually understanding our patterns. 85% of the time, we appear at the boundaries of the Earth's plates, and the remaining 15% is just wandering around. Human research results are indeed reliable. We tend to appear frequently in seismic belts, and outside of these belts, we might occasionally bubble up when we're in a good mood.

Now, let me briefly introduce some of the signs of our appearance so that you can prepare in advance and prevent any bad consequences if we lose control. Some micro signs are not easily noticeable to human senses and require instruments to measure, such as ground deformation, changes in the Earth's magnetic and gravitational fields, changes in the chemical composition of groundwater, and minor earthquake activity. Macro signs are noticeable to the senses and usually occur just before we appear, such as changes in well water levels and clarity, unusual animal behavior, and seismic sounds and lights. Do you all understand? Remember this well, and I hope our next visit doesn't harm you!