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magnitude of large earthquakes generated along large faults in which the ruptures reach the
surface. Moment magnitude can also be calculated using data from seismograms.

Task 2. Build up a glossary to the most important terms used in the text.

Task 3. Answer the questions:
1. What are two fundamentally different measures that describe the size of an earthquake
2. Which of them is quantitative measurement?
3. What information does the Modified Mercalli Intensity Scale provide about an earthquake?
4. What are the pros and cons of Richter Magnitude Scale?
5. Why is the moment magnitude scale favoured over the Richter scale?

Task 4. Look at Figure 10.1. It is Modified Mercalli Intensity Scale. Discuss it using
the table as well as the information from the text.

Task 5. Look at Figure10.2. Here the size or magnitude of an earthquake (left side)
compared to the number of earthquakes of various magnitudes that occur worldwide each
year. The largest earthquakes occur less than once a year, whereas strong earthquakes
happen more than once a month; weak quakes, those less than magnitude 2, occur
hundreds of times per day. Comment on the table (magnitude, examples of the
earthquakes, energy equivalents and energy release).

TEST YOURSELF

Task 1. Tell whether the sentences are true or false. Correct the false ones.
1. Traces of salt in soil and water are often good indications of the proximity of a petroleum
trap.
2. In an exploratory area, surface samples of rocks and soils are taken to indicate a petroleum
trap.
3. Vitrinite reflectance is a method used to determine the maturity of a source rock.
4. The percentage of water reflected from the vitrinite is dependent on the maturity of the
source rock.
5. A source rock, a reservoir rock, a trap and the timing are the four major geological factors
for the success of a particular prospect.
6. A trend or fairway is the exact location where the geological and economic conditions are
favorable for drilling an exploratory well.
7. A trap includes a reservoir rock configuration that has four-sided closure, a seal on the
reservoir rock, and no breach of the trap.
8. There are three fundamentally different measures that describe the size of an earthquake:
intensity, magnitude and longitude.
9. The Richter scale has no drawbacks.
10. Moment magnitude scale determines the strain energy released along the entire fault
surface.

UNIT 11
PETROLEUM EXPLORATION – GEOPHYSICAL TECHNIQUES

Task 1. Read and memorize the following words:
acceleration - прискорення pickup truck – вантажне авто-пікап
can be mounted in a stinger – встановлений з subsurface – підземний пласт; нижні
жорстким кріпленням горизонти; надра
milligal – мілігал – одиниця виміру точності value - значення