地震的能量:TNT、原子弹及以上

The Gutenberg-Richter Energy Formula

The 古登堡—里克特定律描述地震频率与震级之间关系的统计规律：震级每增加一个单位，地震发生频率约降为原来的十分之一。 law is best known for the frequency-magnitude relationship — the observation that small earthquakes are vastly more common than large ones. But Beno Gutenberg and Charles Richter also developed one of the most important formulas in seismology: the relationship between 震级量化地震所释放总能量的单一数值。震级每增加一个整数单位，释放的能量约增加31.6倍。 and 地震能量地震辐射出的总地震能量，以焦耳为单位测量。9级地震释放的能量约相当于25,000颗核弹。. Their empirical formula, derived from measurements on real earthquakes, expresses radiated seismic energy as a function of magnitude.

The formula used in modern form is: log10(E) = 5.24 + 1.44 × Mw, where E is in joules. This gives the seismic energy — the energy radiated as 地震波由地震或爆炸产生并在地球内部传播的弹性波。地震波将震源释放的能量传送到远处地点。s, not the total energy released by fault motion (some energy goes into heat, fracturing new rock surfaces, and permanent deformation). For a magnitude 5.0 earthquake, this formula gives approximately 2 × 10^12 joules. For a magnitude 9.0, it gives approximately 2 × 10^18 joules — one million times more.

Earthquake Energy in Human Terms: TNT and Atomic Bombs

To make earthquake energy tangible, seismologists often compare it to familiar explosive devices. One tonne of TNT releases approximately 4.2 × 10^9 joules. One kiloton (1,000 tonnes) of TNT — the unit used for nuclear weapons — releases about 4.2 × 10^12 joules.

A magnitude 5.0 earthquake releases about 480 kilotons of TNT equivalent — similar to a small nuclear weapon. A magnitude 6.0 releases approximately 15 megatons (15,000 kilotons), larger than the most powerful nuclear weapons ever tested. A magnitude 8.0 releases energy equivalent to approximately 15,000 megatons — far exceeding the total yield of all nuclear weapons ever detonated in history. The 1960 Valdivia earthquake at magnitude 9.5 released approximately 180,000 megatons of energy — equivalent to detonating a nuclear bomb of that size, which fortunately does not exist.

Each Magnitude Step = 31.6x More Energy

The most important number to remember about earthquake energy is 31.6 — the factor by which energy increases for each whole magnitude unit. This comes directly from the 1.44 coefficient in the energy formula: 10^1.44 ≈ 27.5, sometimes rounded to 31.6 when accounting for slightly different formulations. Each step up the magnitude scale multiplies the energy by about 31.6.

This means: magnitude 5 to 6 is 31.6 times more energy; magnitude 5 to 7 is 31.6 × 31.6 ≈ 1,000 times more energy; magnitude 5 to 9 is 31.6^4 ≈ one million times more energy. The practical implication is that the largest earthquakes completely dominate global seismic energy release. The global average of about 1,000 magnitude 5.0 earthquakes per year releases less total energy than a single magnitude 8.0 earthquake. A single magnitude 9.5 earthquake releases more energy than all other earthquakes in that year combined, in most years.

Comparing Earthquake Energy to Other Events

The energy scales involved in earthquakes help explain why even apparently small events can be powerful. A magnitude 4.0 earthquake releases energy comparable to 30,000 tonnes of TNT — roughly equivalent to a small tactical nuclear weapon. A magnitude 7.0 releases energy equivalent to 30 megatons, far exceeding the largest nuclear test ever conducted (the USSR's Tsar Bomba at about 50 megatons, which was magnitude 5.0 seismically).

Volcanic eruptions provide another comparison point. The 1980 Mount St Helens eruption released energy roughly equivalent to a magnitude 7.6 earthquake. The 1815 Tambora eruption — the most powerful in recorded history — may have released energy comparable to a magnitude 8+ seismic event. Tropical cyclones release enormous energy, but most of it is thermal rather than mechanical, making direct comparison complex. In terms of purely mechanical energy released suddenly and destructively, large earthquakes are unmatched by any phenomenon short of asteroid impacts.

Where Does All That Energy Go?

Of the enormous energy released during an earthquake, only a fraction travels as 地震波由地震或爆炸产生并在地球内部传播的弹性波。地震波将震源释放的能量传送到远处地点。s to cause ground shaking. The 地震矩衡量地震释放总能量的指标，由断层面积、平均位移量与岩石的剪切模量相乘计算得出，是矩震级的计算基础。 represents the total mechanical work done by fault motion, which is typically 10 to 100 times larger than the radiated seismic energy. Most of the total energy budget goes into heating the fault zone through friction — essentially, the fault surfaces sliding past each other generate heat just as rubbing your hands together does, but at enormous pressures and over great distances.

Some energy goes into creating new fracture surfaces within the fault zone and in the surrounding rock. Some is stored elastically as permanent deformation of the crust — the GPS大地测量利用全球定位系统接收机以毫米级精度测量构造板块运动和地壳变形的方法，可揭示地震之间断层上应变积累的过程。 measurements that detect crustal deformation following large earthquakes are measuring the permanent redistribution of this elastic strain energy. The fraction that radiates as seismic waves — typically 5–25 percent of the total energy budget — is what causes the shaking that destroys buildings. Use the Earthquake Energy Calculator to explore how different magnitudes compare in terms of energy, TNT equivalents, and shaking parameters.

Using the Earthquake Calculator to Explore Energy

Understanding earthquake energy becomes intuitive when you can compare magnitudes interactively. The Earthquake Energy Calculator lets you enter any magnitude and instantly see the energy in joules, TNT equivalents, and Hiroshima bomb equivalents. You can compare two magnitudes side by side to feel the logarithmic difference — the difference between a magnitude 7.0 and 8.0 is always 31.6 times, regardless of which magnitudes you compare.

The calculator also illustrates the frequency-magnitude relationship: for every magnitude 8.0 earthquake, there are roughly 10 magnitude 7.0 earthquakes and 100 magnitude 6.0 earthquakes annually worldwide. Visualising this pyramid helps explain why the rare great earthquakes dominate global energy statistics even though they occur far less frequently than moderate events. The 地震矩衡量地震释放总能量的指标，由断层面积、平均位移量与岩石的剪切模量相乘计算得出，是矩震级的计算基础。 approach underpinning 矩震级衡量地震规模的现代标准（Mw），基于地震矩——即断层面积、平均滑动量与岩石刚度的乘积。对任何规模的地震都能给出准确结果。 ensures that the calculator's energy values are physically meaningful, grounded in the actual fault mechanics rather than instrument calibration curves.