A device that provides early warning of
a landslide by monitoring vibrations 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, the scientists say. Such natural disasters are common in
countries that experience sudden, heavy rainfall, and can also he triggered by
earthquakes and even water erosion. 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 Loughborough University, UK.
He says a warning system that monitors this movement might be enough to evacuate
a block of fiats or clear a road, and save lives. The most
common way to monitor a slope for signs of an imminent landslide is to watch for
changes in its shape. Surveyors can do this by measuring a site directly, or
sensors sunk into boreholes 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 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 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 be 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 the first paragraph refer to?
A. Sudden, heavy rainfall.
B. Earthquakes.
C. Water erosion.
D. Landslides.
【正确答案】
D
【答案解析】[解析] 短文第一段第一句告诉我们，英国研究人员正在测试一种仪器，这种仪器可以通过监测土壤的振动来预警山崩。该段最后一句说，这种灾难经常在一些遭受自然灾害的国家发生，这些自然灾害包括“sudden, heavy rainfall”和“earthquakes”以及“water erosion”，所以只有D可以指代这种灾难了。
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.
D. All of the above.
【正确答案】
D
【答案解析】[解析] A，B，C三项的内容都可在第二段中找到，所以D是正确答案。
单选题
Why do researchers develop a new device to monitor signs of landslides?
A. Because the new device can measure the site directly.
B. Because the new device can be sunk into boreholes or fixed above
ground.
C. Because the common methods can cause false alarms.