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The massive 8.8 quake, the seventh strongest in recorded history, hit Chile and should have shortened the length of an Earth day by 1.26 milliseconds, More impressive is how much the quake shifted the Earth’s axis（地轴）.
The computer mode! Used to determine the effects of the Chile earthquake effect also found that it should have moved the Earth’s figure axis by about 8 cm. The Earth’s figure figure axis is not the same as its north-south axis, which Earth turns around once every day at a speed of about 1,604 kph. The figure axis is the axis around which the Earth’s mass is balanced. It is offset（偏离） from the Earth’s north-south axis by about 10 meters.
Strong earthquakes can change Earth’s days and its axis. The 9.1 Sumatran earthquake in 2004, which set off a deadly tsunami（海啸），should have shortened Earth’s days by 0.0068 milliseconds and shifted its axis by about 7cm.
One Earth day is about 24 hours long. Over the course of a year, the length of a day normally changes gradually by one millisecond, It increases in the winter when Earth more slowly, and decreases in the summer.
The Chile earthquake was much smaller than the Sumatran quake, but its effects on the Earth are larger because of its location. The fault（断层） responsible for the 2010 Chile quake also cuts through Earth at a larger angle that the Sumatran quake’s fault. This makes the Chile fault ore effective in moving the Earth’s mass vertically and hence more effective in shifting the Earth’s figure axis.
The findings are based on early date available on the Chile earthquake. The Chile earthquake has killed more than 700 people and cause widespread damage in the South American country.
64．What’s the biggest problem caused by the Chile quake?
A．It is the seventh strongest in recorded history.
B．It should have shortened the length of an Earth day.
C．It shifted the Earth’s axis.
D．It made the day longer on Earth.
65．Comparing the Sumatram earthquake with the Chile earthquake, we know that__________.
A．the Sumatram earthquake had more effect on Earth
B．the location of the Chile earthquake is responsible for its larger effects on Earth.
C．the Sumatram earthquake was less destructive
D．the Chile earthquake fault changed the Earth’s mass
66．What does the word “it” in the 4th paragraph refer to?
A．The leng of a day. B．The axis.
C．One millisecond. D．The change of the day.
