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Geophysicist Dr. Andrea Donnellan of NASA's Jet Propulsion Labor
2024-08-23英语阅读（二）(00596)
Geophysicist Dr. Andrea Donnellan of NASA's Jet Propulsion Laboratory, Pasadena, Calif., remembers the morning of January 17, 1994, like few others. Like millions of other Southern California residents, she was shaken from her sleep in her normally tranquil foothill community home as a large earthquake caused a mountain, located just 30 miles away, to grow nearly 15 inches higher, all in a matter of seconds.
"Large earthquakes are always disconcerting," she said. "Being a geophysicist I was immediately interested in how large the earthquake was and where it had occurred."
Less than two months before that fateful day, Donnellan and colleagues from the Massachusetts Institute of Technology had published a landmark paper in the journal Nature on ground distortion north of LA's San Fernando Valley. Six years of relatively sparse data from a fledgling network of Global Positioning System (GPS) deformation monitors, that had been developed and installed around Southern California by scientists at JPL and other organizations, had detected that Earth's crust was being squeezed closed across the Ventura Basin. The data showed the area's faults were accumulating strain, and they gave the scientists clear indications of the style and relative size of an earthquake that might strike there, even though the faults there do not all break the surface. They placed no time frame on when such a temblor might occur, however.
"The Northridge GPS measurements solidified in many scientists" minds how valuable data from space-based instruments could be for collecting precise measurements of Earth's crustal movements," said Donnellan. "We knew that something was up because an earthquake had not occurred there historically and yet a large amount of strain needing to be released had accumulated. After the earthquake, additional GPS data made it possible to rapidly and uniquely determine where the fault ruptured and to measure how the earthquake had deformed Earth's surface."
In the decade since Northridge, a high-tech, GPS-based ground deformation network was installed within Southern California. Called the Southern California Integrated GPS Network, it provides a continuous measurement of ground deformation at 250 locations with a precision of a few millimeters, measuring the slow buildup of deformation along faults. In addition, advances in satellite-based radar Interferometric Synthetic Aperture Radar (InSAR) and lidar are now used in combination with the GPS measurements to provide images of ground deformation for the entire Southern California earthquake region. These new technologies, coupled with powerful new computer modeling capabilities, have revitalized research in understanding earthquakes and earthquake processes. The new technologies will substantially refine earthquake hazard maps.
Northridge GPS can be used to______.
A、define the faults of Earth's crust
B、forecast the potential earthquake
C、provide valuable data for scientists
D、detect the eruption of a volcano
【正确答案】：C
"Large earthquakes are always disconcerting," she said. "Being a geophysicist I was immediately interested in how large the earthquake was and where it had occurred."
Less than two months before that fateful day, Donnellan and colleagues from the Massachusetts Institute of Technology had published a landmark paper in the journal Nature on ground distortion north of LA's San Fernando Valley. Six years of relatively sparse data from a fledgling network of Global Positioning System (GPS) deformation monitors, that had been developed and installed around Southern California by scientists at JPL and other organizations, had detected that Earth's crust was being squeezed closed across the Ventura Basin. The data showed the area's faults were accumulating strain, and they gave the scientists clear indications of the style and relative size of an earthquake that might strike there, even though the faults there do not all break the surface. They placed no time frame on when such a temblor might occur, however.
"The Northridge GPS measurements solidified in many scientists" minds how valuable data from space-based instruments could be for collecting precise measurements of Earth's crustal movements," said Donnellan. "We knew that something was up because an earthquake had not occurred there historically and yet a large amount of strain needing to be released had accumulated. After the earthquake, additional GPS data made it possible to rapidly and uniquely determine where the fault ruptured and to measure how the earthquake had deformed Earth's surface."
In the decade since Northridge, a high-tech, GPS-based ground deformation network was installed within Southern California. Called the Southern California Integrated GPS Network, it provides a continuous measurement of ground deformation at 250 locations with a precision of a few millimeters, measuring the slow buildup of deformation along faults. In addition, advances in satellite-based radar Interferometric Synthetic Aperture Radar (InSAR) and lidar are now used in combination with the GPS measurements to provide images of ground deformation for the entire Southern California earthquake region. These new technologies, coupled with powerful new computer modeling capabilities, have revitalized research in understanding earthquakes and earthquake processes. The new technologies will substantially refine earthquake hazard maps.
Northridge GPS can be used to______.
A、define the faults of Earth's crust
B、forecast the potential earthquake
C、provide valuable data for scientists
D、detect the eruption of a volcano
【正确答案】：C
