Geology topics
Publications and source records attributed to R.E. Needham.
Moment-tensor solutions, estimated using optimal filter theory, are listed for 133 moderate-to-large earthquakes occurring during 1992. ?? 1994.
Moment-tensor solutions, estimated using optimal filter theory, are listed for 130 moderate-to-large size earthquakes occurring during 1993. ?? 1994.
Moment-tensor solutions, estimated using optimal filter theory, are listed for 114 moderate-to-large size earthquakes occurring during 1990. ?? 1992.
Moment-tensor solutions, estimated using optimal filter theory, are listed for 201 moderate-to-large earthquakes occurring from 1988 to 1989. ?? 1991.
Moment-tensor solutions, estimated using optimal filter theory, are listed for 426 moderate- to large-sized earthquakes occurring from 1984 to 1987. ?? 1989.
The National Earthquake Information Center of the US Geological Survey has three main missions. First, the NEIC determines as rapidly and as accurately as possible, the location and size of all destructive earthquakes that occur worldwide. Second, the NEIC collects and provides to scientists and to the public an extensive seismic database that serves as a solid foundation for scientific research. Third, the NEIC pursues an active research program to improve its ability to locate earthquakes and to understand the earthquake mechanism. These efforts are all aimed at mitigating the risks of earthquakes to mankind. -from Authors
Mexico was hit by one of the most devastating earthquakes in its history on September 19, 1985 at 7:18 a.m. MDT time. this earthquake, which was centered about 380 kilometers west-southwest of Mexico City, had a surface-wave magnitude of 8.1. In less than a minute, seismic waves from this earthquake had traveled to Mexico City. At this early hour, people were beginning to get ready for the day's work. Without warning, buildings in some sections of the city began to shake violently. A few minutes later, 412 buildings had collapsed and another 3,124 were badly damaged (figure 1). Most communication systems linking Mexico City to the rest of the world were damaged or rendered inoperable. At least 9,500 people were killed, 30,000 were injured and 100,000 were left homeless by this earthquake. According to some unconfirmed reports, the death toll from this earthquake may have been as high as 35,000. this earthquake is estimated to have seriously affected an area of 825,000 square kilometers, caused between 3 and 4 billion dollars in damage, and been felt by 20 million people.
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