Earthquake Science | Earthquake Senior Players, learn about it

In the broadcast of earthquake information, the least element is the earthquake level. The magnitude of the earthquake is one of the amount of earthquake energy and one of the basic parameters of the earthquake.

But this is the earthquake that everyone is accustomed to it. In fact, it is not easy to calculate at all, and there are many "gameplay", and the results are not the same.

The term "earthquake" has been widely recognized since it was proposed in 1935. All countries and international seismic institutions have established different formulas based on their own situation.

The magnitude of a earthquake is calculated with different formulas. How can this be played?

First of all, we must figure out, why can a earthquake be derived by different formulas, and the earthquake level is so special?

Earthquake calculations are not like "distance = time × speed". There are only corresponding formulas. In essence, it is different from the pyrata theorem and circular area formula we have learned. Experience formula.

What is an experience formula?

It is summarized from the past data, not the function formula obtained by complete theoretical derivation.

After obtaining a large amount of earthquake observation data, we found measurement parameters that could affect the magnitude of the earthquake, and found a functional relationship between the earthquake energy and measurement parameters through a large number of seismic instances. In the process of actual derivation and solution, there may be more than one optimal solution, which will produce a lot of experience formulas. They reflect the different characteristics of the earthquake energy and the earthquake level. Different earthquake -level computing methods such as earthquake -level and body waves. These are traditional earthquakes.

In "The Class of" Lost ", we mentioned that the traditional earthquake level has a pain point that cannot be resolved is" earthquake saturation ". In order to solve this problem, it has developed a" no upper limit "modern earthquake level.

Modern shock

Modern earthquake levels are divided into torque magnitude and energy earthquakes. The latter is related to the physical parameters of the earthquake, that is, the radiation earthquake energy. It is represented by ME, which is essentially using the seismic energy to represent the size of the earthquake.

As a modern earthquake level, the torque magnitude MW is determined by the seismic torque (a physical quantity that describes the mechanical strength of the earthquake, and the concept similar to the torque) determines the earthquake level. However, the earthquake torque is used to use earthquake waves to solve the source of earthquakes. The process of counter -discrimination may indeed point to multiple solutions, and there are many uncertainties in the middle. The earthquake is also like a box of chocolate. We dare not pack tickets before eating.

Therefore, why do we still have to develop the type of modern earthquake after having a traditional earthquake -class three swordsman now?

Of course it is useful.

Uh ... Listening to Jun's words, it is better than a word.

The traditional earthquake level is the magnitude A of the "single -frequency" seismic wave (P wave, S wave, or face wave) measured. Commonly used are local earthquake -grade ML, face wave shock MS, and body wave shock -level MB.

Modern earthquake levels are determined by the area S, fault misalignment of faults of faults.

We often say that aside the phenomenon to see the essence and look at the difference between the two. If the earthquake wave level and cycle (traditional earthquake) are tending to the phenomenon, the area of ​​the rupture of the fault, the average number of faults, the energy of the earthquake waves of the earthquake source, etc. Parameters (modern earthquakes) are closer to the essence of misplaced and rupture at the moment of the earthquake.

Compared with the traditional earthquake level, the biggest "killer" in modern earthquakes is that it does not have "earthquake saturation".

Magnolia

Just like you can't use mercury thermometers to measure the boiling water, because the upper limit of the temperature meter measurement is 42 degrees, and the maximum display is 42 degrees, reaching the earthquake saturation. No matter the energy of the earthquake, the magnitude of the earthquake will not change.

This problem does not exist at the moment. For example, the Alaska earthquake in 1964 reached 9.1, but the face wave shock MS was only 8.4, and the body wave shock MB was only 6.2. The body wave shock MB is only 7.2. A large number of huge shocks prove the saturation of traditional earthquakes. Therefore, when treating some great earthquakes, the world is usually used to identify the magnitude of the earthquake.

In summary, the Murdarial MW and Energy Seismic ME are the "docking" of the face wave shock MS. When the face wave shock -level MS does not reach the earthquake saturation, the two are basically the same as the MS. The torque magnitude and energy earthquake level will take over the "unfinished mission" of the surface of the face wave, which truthfully reflects the real energy size of the earthquake.

Data reference:

"The Development and Outlook of Earthquake Measurement Technology" Liu Ruifeng

There are so many earthquakes! How to distinguish ML, MB, MB, MS, MW?

Source: Zhenzhi Zhuojian

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