Disaster Management · TEE · practice

Two additional authored calculation exercises

Optional calculation practice

Supplementary worked examples · no numerical question found in the available 12 TEE sittings

Added runoff and magnitude exercises. Their numbers and question selection were written for practice; this is not a recovered paper or a confirmed M2/TEE composition.

Illustrative calculation (not a PYQ). A catchment has C = 0.6, I = 50 mm/h and area = 0.5 km². Estimate peak runoff in m³/s using the rational method.

Answer

Given

Given	Value
Runoff coefficient C	0.6
Rainfall intensity I	50 mm/h
Catchment area A	0.5 km²

To find

Estimated peak runoff Q in m³/s.

Formula and why

Q=0.27778CIA

The factor converts mm/h over km² to m³/s. Assume the rainfall intensity and catchment meet the rational-method assumptions.

Step-by-step solution

Step 1. Multiply coefficient and intensity

0.6\times50=30

Step 2. Multiply by catchment area

30\times0.5=15

Step 3. Convert to discharge

Q\approx0.27778\times15=4.1667\,\mathrm{m^3/s}

Final answer: Approximately 4.17 m³/s.

Illustrative calculation (not a PYQ). Two earthquakes have magnitudes 6 and 5. Find the amplitude ratio and approximate energy ratio.

Answer

Given

Quantity	Value
Larger magnitude	6
Smaller magnitude	5

To find

Larger-to-smaller amplitude and energy ratios.

Formula and why

A_2/A_1=10^{\Delta M},\qquad E_2/E_1\approx10^{1.5\Delta M}

Magnitude is logarithmic. The energy relation has a different exponent from the amplitude relation.

Step-by-step solution

Step 1. Calculate magnitude difference

\Delta M=6-5=1

Step 2. Calculate amplitude ratio

10^1=10

Step 3. Calculate energy ratio

10^{1.5\times1}=10^{1.5}\approx31.62

Final answer: Amplitude ratio 10:1; approximate energy ratio 31.62:1.