Listening Device Provides Landslide(山崩；地滑；塌方) Early
Warning
A device that provides early warning of
a landslide by monitoring vibrations(振动)in soil is being tested by UK
researchers. The device could save thousands of lives each year by warning when
an area should be evacuated(疏散，撤走), the scientists say. Such
natural disasters are common in countries that experience sudden,
heavy rainfall(降雨), and can also be triggered by earthquakes and even water
erosion(腐蚀，侵蚀). Landslides start when a few particles of soil
or rock within a slope start to move, but the early stages can be hard to spot.
Following this initial movement, "slopes can become unstable in a matter of
hours or minutes," says Nell Dixon at Southborough University, UK. He says a
warning system that monitors this movement "might be enough to evacuate a block
of flats or clear a road, and save lives". The most common way
to monitor a slope for signs of an imminent(即将发生的) landslide is to watch for
changes in its shape. Surveyors can do this by measuring aside directly, or
sensors(传感器) sunk into boreholes(钻孔，井眼) or fixed above ground can be used to
monitor the shape of a slope. Slopes can, however, change shape without
triggering a landslide, so either method is prone to causing false alarms. Now
Dixon's team has developed a device that listens for the vibrations caused when
particles begin moving within a slope. The device takes the
form of a steel pipe dropped into a borehole in a slope. The borehole is filled
in with gravel(砾，砂砾，砾石) around the pipe to help transmit high- frequency
vibrations generated by particles within the slope. These vibrations pass up the
tube and are picked up by a sensor on the surface. Software analyses the
vibration signal to determine whether a landslide may be imminent.
The device is currently being tested in a 6-metre-tall artificial clay
embankment(堤岸) in Newcastle, UK. Early results suggest it should provide fewer
false positives than existing systems. Once it has
been carefully and thoroughly tested, the device could be used to create a
complete early-warning system for dangerous slopes. "Locations
with a significant risk of landslides could definitely benefit from a machine
like this," says Adam Poulter, an expert at the British Red Cross. "As long as
it doesn't cost too much." But, Poulter adds that an early-warning system may
not enough on its own. "You need to have the human communication," he says.
"Making systems that get warnings to those who need them can be
difficult."
单选题
What does "such natural disasters" in Paragraph 1 refer to?
A. Sudden, heavy rainfall.
B. Earthquakes.
C. Water erosion.
D. Landslides.
【正确答案】
D
【答案解析】[解析] 短文第一段第一句提到了山体滑坡，此处的自然灾害指的是上文的山体滑坡，故选D。
单选题
Which of the following statements is true of landslides?
A. The initial movement is hard to spot.
B. They start with a movement of a few particles of soil or rock.
C. They can be destructive in a matter of hours or minutes.