지진 에너지 계산기

Convert earthquake magnitude to energy equivalent in joules, TNT tons, and atomic bombs.

Calculation

지진 에너지와 규모 이해

지진 규모는 로그 척도로 측정되며, 이는 정수 단위 증가마다 측정 진폭이 10배 증가하고 방출 에너지가 약 31.6배 증가함을 의미합니다. 이 지수적 관계는 구텐베르크-리히터 에너지-규모 공식 log₁₀(E) = 1.5M + 4.8로 설명되며, 여기서 E는 줄 단위의 에너지이고 M은 모멘트 규모입니다. 규모 7.0 지진은 규모 5.0 지진보다 약 1,000배 더 많은 에너지를 방출하며, 이는 TNT 50만 톤을 폭발시키는 것과 대략 동등합니다.

대부분의 목적에서 원래의 리히터 척도를 대체한 모멘트 규모 척도(Mw)는 단층 미끄러짐에 의해 방출된 총 에너지를 측정하는 지진 모멘트에 기반합니다. 리히터 국지 규모(ML)와 달리 모멘트 규모는 높은 값에서 포화되지 않아 대규모 지진에 선호되는 척도입니다. 지진 모멘트는 암석의 강성, 파열된 단층 면적, 단층을 따른 평균 변위의 세 가지 요소에 따라 달라집니다.

계산의 과학적 원리

리히터 척도는 1935년 찰스 리히터가 남부 캘리포니아 지진을 위해 개발했으며, 1970년대에 모멘트 규모 척도가 전 세계적으로 이를 대체했습니다.
전체 지진 에너지의 약 1~10%만이 지진파로 방사되며, 나머지는 암석 파쇄와 단층을 따른 열 발생에 소비됩니다.
TNT 등가치는 직관적인 비교를 제공합니다: 2011년 규모 9.1의 도호쿠 지진은 약 6억 톤의 TNT에 해당하는 에너지를 방출했습니다.
소규모 지진(M2~3)은 수 킬로그램의 폭발물에 해당하는 에너지를 방출하고, 대규모 지진(M8+)은 핵무기에 필적하는 에너지를 방출합니다.

일반적인 용도

역사적 지진의 상대적 에너지를 비교하여 파괴력 이해.
지구과학 수업에서 학생들에게 로그 척도와 지수적 에너지 관계 교육.
TNT나 낙뢰 같은 일상적인 에너지 등가물을 사용하여 지진 규모를 이해.

How to Use

1
Enter the Earthquake Magnitude
Input the moment magnitude (Mw) of the earthquake. Mw is the standard scale used by seismological agencies since the 1970s and is the most accurate measure across all magnitude ranges.
2
Select Your Energy Units
Choose whether to see energy equivalents in joules, kilotons of TNT, or Hiroshima atomic bomb equivalents. The calculator applies the USGS energy-magnitude relation: log E = 5.24 + 1.44 Mw.
3
Compare Across Magnitudes
Add a second magnitude to see the energy ratio between the two events. Because the scale is logarithmic, each unit increase in Mw corresponds to about 31.6 times more released energy.

About

Earthquake energy and magnitude are connected through one of science's most consequential logarithmic scales. Charles Richter introduced the local magnitude (ML) scale in 1935, calibrated to a specific seismograph at a specific distance in Southern California. While the name 'Richter scale' persists in popular usage, seismologists now use moment magnitude (Mw), developed by Hiroo Kanamori and Thomas Hanks in 1979, which remains consistent across the full spectrum from microearthquakes to the largest megathrust events and does not saturate at high magnitudes as earlier scales did.

The physical quantity underlying Mw is the seismic moment (M0), calculated as M0 = μ × A × d, where μ is the shear modulus of the rock (typically 3 × 10^10 Pa for the crust), A is the ruptured fault area, and d is the average displacement across the fault. Mw is then derived as Mw = (2/3) × log10(M0) − 6.07. This formulation means that fault geometry directly determines magnitude: a rupture covering a 200 × 100 km fault plane with 5 m of average slip yields a specific, calculable M0 and hence a well-defined Mw.

Energy equivalents help communicate earthquake power to non-specialist audiences. The most commonly cited comparison is the atomic bomb: the Hiroshima bomb released approximately 63 terajoules. A magnitude 6.0 earthquake releases energy comparable to about 1 Hiroshima bomb, while a magnitude 8.0 releases energy comparable to about 1,000. These comparisons, while vivid, can mislead: earthquake energy is released over a fault plane tens to hundreds of kilometers long over tens of seconds, and only a fraction couples into the seismic waves that cause damage at the surface. The depth, focal mechanism, and local site response all shape the destruction as much as the raw energy figure.

FAQ

규모와 진도의 차이는 무엇인가요?

Magnitude is an objective, instrumentally measured quantity describing the total energy released at the earthquake source, reported as a single number regardless of where it is measured. The moment magnitude scale (Mw) is now universal and calculated from the seismic moment—the product of the fault area, average slip, and rock rigidity. Intensity, by contrast, is a subjective measure of ground shaking severity at a specific location, described by the Modified Mercalli Intensity (MMI) scale from I (not felt) to XII (total destruction). Intensity decreases with distance from the epicenter and varies with local geology, so the same earthquake can produce MMI V in one city and MMI VIII in another.

How much energy does a magnitude 7 earthquake release?

Using the USGS energy-magnitude relation (log E = 5.24 + 1.44 Mw), a magnitude 7.0 earthquake releases approximately 2 × 10^15 joules, equivalent to roughly 475 kilotons of TNT or about 32 Hiroshima-sized atomic bombs. For comparison, a magnitude 8.0 releases about 31.6 times more energy than a 7.0, and a magnitude 9.0 releases about 1,000 times more. The 2011 Tohoku M9.1 earthquake released energy equivalent to approximately 600 million tons of TNT, or about 40,000 Hiroshima bombs. It is worth noting that seismic energy represents only a fraction (roughly 5–10%) of the total strain energy released; the rest is converted to heat at the fault surface.

Why does each magnitude unit feel so much stronger?

The moment magnitude scale is logarithmic in seismic moment but the energy-magnitude relationship has a steeper exponent. A one-unit increase in Mw corresponds to a factor of 10^1.5 ≈ 31.6 in energy release. Peak ground acceleration (the shaking you actually feel) scales differently: a one-unit increase in Mw roughly doubles the felt shaking amplitude as measured by instruments, though local site conditions, depth, and distance complicate this relationship. This is why the jump from M6.0 to M7.0 is so consequential for structural damage—the energy released increases by a factor of roughly 32, but the duration of strong shaking also increases substantially, compounding structural fatigue.

What is the largest earthquake ever recorded?

The 1960 Valdivia earthquake in southern Chile holds the record at M9.5, occurring along the Nazca–South American subduction zone. It ruptured approximately 1,000 km of fault surface, generated a transoceanic tsunami that killed people as far away as Hawaii and Japan, and triggered volcanic activity in the Andes. The seismic moment released was approximately 1.8 × 10^23 newton-meters. In comparison, the 2004 Sumatra–Andaman earthquake (M9.1–9.3) and the 2011 Tohoku earthquake (M9.1) are the next largest recorded events. All occurred at subduction zone megathrusts, the only tectonic setting capable of producing such extreme events.

Is a magnitude 10 earthquake possible?

A magnitude 10.0 earthquake is considered physically implausible given the geometry of Earth's plate boundaries. The magnitude is determined by fault dimensions and average slip: a M10.0 would require a fault rupture of roughly 4,000–5,000 km in length, more than the entire length of the longest subduction zone on Earth (the Chile-Peru trench). While cascading multi-segment ruptures are possible—the 1964 Alaska earthquake ruptured about 800 km—no tectonic configuration exists that could sustain a single coherent rupture at M10 scale. The theoretical upper bound for subduction zone earthquakes is generally placed around M9.5–9.6.