Earthquake Trivia

You said:

When was the Boxing Day Tsunami?

ChatGPT

The Boxing Day Tsunami occurred on December 26, 2004. It was caused by a massive undersea earthquake off the coast of Sumatra, Indonesia, with a magnitude of 9.1–9.3. The resulting tsunami devastated coastal areas in 14 countries around the Indian Ocean, making it one of the deadliest natural disasters in recorded history.

You said:

How much water was displaced?

ChatGPT

The Boxing Day Tsunami of 2004 was triggered by the displacement of approximately 30 cubic kilometers (7.2 cubic miles) of water. This displacement resulted from a massive rupture along the Sunda Megathrust fault, where the Indian Plate was subducted beneath the Burma Plate.

The rupture stretched about 1,300 kilometers (810 miles) in length and up to 50 kilometers (31 miles) in width, with vertical displacements of the seafloor ranging from 4 to 8 meters (13 to 26 feet). This rapid movement displaced an enormous volume of seawater, generating the devastating tsunami waves that radiated across the Indian Ocean.

You said:

How much energy did it take to displace that much water?

ChatGPT

To estimate the energy required to displace approximately 30 cubic kilometers of water in the Boxing Day Tsunami, we can use the formula for gravitational potential energy:

E=mghE = mghE=mgh

Where:

• EEE = energy (in joules)

• mmm = mass of the displaced water (in kilograms)

• ggg = acceleration due to gravity (9.8 m/s29.8 \, \text{m/s}^29.8m/s2)

• hhh = average vertical displacement of the seafloor (in meters)

Step-by-Step Calculation:

1. Volume of displaced water (VVV):
   V=30 km3=30×109 m3V = 30 \, \text{km}^3 = 30 \times 10^9 \, \text{m}^3V=30km3=30×109m3

2. Mass of displaced water (mmm):
   The density of water (ρ\rhoρ) is 1000 kg/m31000 \, \text{kg/m}^31000kg/m3.
   m=ρV=1000×30×109=3×1013 kgm = \rho V = 1000 \times 30 \times 10^9 = 3 \times 10^{13} \, \text{kg}m=ρV=1000×30×109=3×1013kg

3. Average displacement height (hhh):
   Let’s use h=6 mh = 6 \, \text{m}h=6m (average vertical displacement range was 4–8 meters).

4. Energy calculation:

E=mgh=(3×1013)×9.8×6E = mgh = (3 \times 10^{13}) \times 9.8 \times 6E=mgh=(3×1013)×9.8×6 E=1.764×1015 joulesE = 1.764 \times 10^{15} \, \text{joules}E=1.764×1015joules

Final Energy Estimate:

The energy required to displace the water was approximately 1.76×1015 joules1.76 \times 10^{15} \, \text{joules}1.76×1015joules.

For comparison, this is about 420 megatons of TNT, which illustrates the immense power of the earthquake that triggered the tsunami.

You said:

How many sticks od dynamite would that be?

ChatGPT

To calculate how many sticks of dynamite would be equivalent to the energy required to displace the water during the Boxing Day Tsunami:

Known Values:

1. Energy from the tsunami displacement:
   1.76×1015 joules1.76 \times 10^{15} \, \text{joules}1.76×1015joules

2. Energy per stick of dynamite:
   A stick of dynamite releases approximately 1 megajoule (1 MJ) of energy (106 joules10^6 \, \text{joules}106joules).

Calculation:

Number of sticks of dynamite=Tsunami energyEnergy per stick of dynamite\text{Number of sticks of dynamite} = \frac{\text{Tsunami energy}}{\text{Energy per stick of dynamite}}Number of sticks of dynamite=Energy per stick of dynamiteTsunami energy​ Number of sticks=1.76×1015 joules1×106 joules/stick\text{Number of sticks} = \frac{1.76 \times 10^{15} \, \text{joules}}{1 \times 10^6 \, \text{joules/stick}}Number of sticks=1×106joules/stick1.76×1015joules​ Number of sticks=1.76×109\text{Number of sticks} = 1.76 \times 10^9Number of sticks=1.76×109

Final Answer:

It would take approximately 1.76 billion sticks of dynamite to release the same amount of energy as the tsunami displacement.

You said:

If that energy could be harnessed, how many 100 light bulbs could it light for a day?

ChatGPT

To calculate how many 100-watt light bulbs the energy from the Boxing Day Tsunami could power for a day:

Known Values:

1. Energy from the tsunami displacement:
   1.76×1015 joules1.76 \times 10^{15} \, \text{joules}1.76×1015joules

2. Energy usage of a 100-watt bulb in one second:
   Power = 100 watts=100 joules/second100 \, \text{watts} = 100 \, \text{joules/second}100watts=100joules/second
   In one day (24 hours=86,400 seconds24 \, \text{hours} = 86,400 \, \text{seconds}24hours=86,400seconds):
   Energy per bulb/day=100×86,400=8.64×106 joules\text{Energy per bulb/day} = 100 \times 86,400 = 8.64 \times 10^6 \, \text{joules}Energy per bulb/day=100×86,400=8.64×106joules

3. Number of bulbs calculation:

Number of bulbs=Tsunami energyEnergy per bulb/day\text{Number of bulbs} = \frac{\text{Tsunami energy}}{\text{Energy per bulb/day}}Number of bulbs=Energy per bulb/dayTsunami energy​ Number of bulbs=1.76×10158.64×106\text{Number of bulbs} = \frac{1.76 \times 10^{15}}{8.64 \times 10^6}Number of bulbs=8.64×1061.76×1015​

4. Perform the division:

Number of bulbs=2.04×108\text{Number of bulbs} = 2.04 \times 10^8Number of bulbs=2.04×108

Final Answer:

The energy from the Boxing Day Tsunami could power approximately 204 million 100-watt light bulbs for a full day.

You said:

That doesn't seem right? It seems like that's too low a number?

ChatGPT

Let's carefully recheck the calculations.

Known Values:

1. Energy from the tsunami displacement:
   1.76×1015 joules1.76 \times 10^{15} \, \text{joules}1.76×1015joules

2. Energy usage of a 100-watt bulb in one day:

   • Power of bulb: 100 watts=100 joules/second100 \, \text{watts} = 100 \, \text{joules/second}100watts=100joules/second

   • Seconds in a day: 24 hours×60 minutes/hour×60 seconds/minute=86,400 seconds24 \, \text{hours} \times 60 \, \text{minutes/hour} \times 60 \, \text{seconds/minute} = 86,400 \, \text{seconds}24hours×60minutes/hour×60seconds/minute=86,400seconds

   • Energy per bulb per day: Energy per bulb/day=100 joules/second×86,400 seconds=8.64×106 joules\text{Energy per bulb/day} = 100 \, \text{joules/second} \times 86,400 \, \text{seconds} = 8.64 \times 10^6 \, \text{joules}Energy per bulb/day=100joules/second×86,400seconds=8.64×106joules

3. Number of bulbs calculation:

Number of bulbs=Total energyEnergy per bulb/day\text{Number of bulbs} = \frac{\text{Total energy}}{\text{Energy per bulb/day}}Number of bulbs=Energy per bulb/dayTotal energy​

Substituting the values:

Number of bulbs=1.76×10158.64×106\text{Number of bulbs} = \frac{1.76 \times 10^{15}}{8.64 \times 10^6}Number of bulbs=8.64×1061.76×1015​

4. Perform the division:

Number of bulbs=1.768.64×1015−6\text{Number of bulbs} = \frac{1.76}{8.64} \times 10^{15 - 6}Number of bulbs=8.641.76​×1015−6 Number of bulbs=0.2037×109=2.037×108\text{Number of bulbs} = 0.2037 \times 10^9 = 2.037 \times 10^8Number of bulbs=0.2037×109=2.037×108

The result still comes to 204 million bulbs.

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Why Does It Seem Low?

While 204 million bulbs is a huge number, it may seem "low" because the energy needed to power a single 100-watt bulb for an entire day (8.64 MJ8.64 \, \text{MJ}8.64MJ) is relatively large compared to a single joule of energy. This emphasizes how much energy everyday electrical devices consume over time. The calculation is correct, but the perception comes down to the high energy consumption of sustained lighting.

You said:

How much water was displaced in the Fukushima Earthquake?

ChatGPT

The 2011 Tōhoku Earthquake (Fukushima Earthquake) displaced a massive volume of water due to the undersea rupture of the Japan Trench. The exact volume of displaced water is challenging to pinpoint precisely, but we can make a reasonable estimate based on the rupture area, displacement height, and geological studies.

Key Details:

1. Rupture Area:

   • Length: ~500 km

   • Width: ~200 km

   • Area: 500 km×200 km=100,000 km2500 \, \text{km} \times 200 \, \text{km} = 100,000 \, \text{km}^2500km×200km=100,000km2

2. Average Vertical Displacement:
   Geological surveys indicate the seafloor displaced by ~5-10 meters on average, with localized areas reaching up to 40 meters.

3. Volume of Displaced Water:
   The displaced volume is approximately the product of the rupture area and the average vertical displacement. Using 7 meters as a mid-range estimate:

Volume=Area×Displacement Height\text{Volume} = \text{Area} \times \text{Displacement Height}Volume=Area×Displacement Height Volume=100,000 km2×7 m\text{Volume} = 100,000 \, \text{km}^2 \times 7 \, \text{m}Volume=100,000km2×7m

Converting units:

100,000 km2=1011 m2100,000 \, \text{km}^2 = 10^{11} \, \text{m}^2100,000km2=1011m2 Volume=1011 m2×7 m=7×1011 m3\text{Volume} = 10^{11} \, \text{m}^2 \times 7 \, \text{m} = 7 \times 10^{11} \, \text{m}^3Volume=1011m2×7m=7×1011m3

Final Estimate:

The 2011 Fukushima Earthquake displaced approximately 700 cubic kilometers (7 × 10¹¹ m³) of water. This is significantly more than the Boxing Day Tsunami's 30 cubic kilometers, reflecting the immense scale of the Tōhoku event.

You said:

Compare the magnitude and duration of both earthquakes.

ChatGPT

The Boxing Day Tsunami (2004) and the Fukushima Earthquake (2011) were both extraordinary seismic events, but they differed significantly in magnitude, duration, and impact.

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Magnitude Comparison

1. Boxing Day Earthquake (2004):

   • Magnitude: 9.1–9.3

   • Location: Off the coast of Sumatra, Indonesia.

   • Type: Megathrust earthquake, caused by the subduction of the Indian Plate beneath the Burma Plate.

   • One of the largest earthquakes ever recorded, releasing immense energy.

2. Fukushima Earthquake (2011):

   • Magnitude: 9.0

   • Location: Off the Pacific coast of Tōhoku, Japan.

   • Type: Megathrust earthquake, caused by the subduction of the Pacific Plate beneath the North American Plate.

   • Slightly less energy than the 2004 event, but still among the most powerful in history.

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Duration Comparison

1. Boxing Day Earthquake (2004):

   • Duration: Approximately 8–10 minutes.

   • One of the longest-lasting earthquakes ever recorded. The long duration contributed to the massive displacement of water and the devastating tsunami.

2. Fukushima Earthquake (2011):

   • Duration: Approximately 6 minutes.

   • While shorter than the Boxing Day Earthquake, the Fukushima event still lasted long enough to cause severe seafloor displacement and trigger a massive tsunami.

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Energy Released

The energy released by an earthquake is proportional to its magnitude and grows exponentially. A 0.1 difference in magnitude represents a significant difference in energy:

• The Boxing Day Earthquake released approximately 2.0 × 10²² joules of energy.

• The Fukushima Earthquake released approximately 1.9 × 10²² joules of energy.

The 2004 earthquake released slightly more energy, but both events were in the same league of destructive power.

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Summary Table:

Feature

Boxing Day Earthquake (2004)

Fukushima Earthquake (2011)

Magnitude

9.1–9.3

9.0

Duration

8–10 minutes

6 minutes

Energy Released

2.0×1022 J2.0 × 10^{22} \, \text{J}2.0×1022J

1.9×1022 J1.9 × 10^{22} \, \text{J}1.9×1022J

Tsunami Impact

14 countries affected

Primarily Japan

Volume of Water Displaced

~30 km³

~700 km³

While the 2004 earthquake had a slightly higher magnitude and longer duration, the 2011 earthquake displaced significantly more water, highlighting differences in the geological context of each event.