Magnitude 4.0 SOUTH DAKOTA
2003 May 25 07:32:32 UTC
Preliminary Earthquake Report
U.S. Geological Survey, National Earthquake Information Center
World Data Center for Seismology, Denver
Magnitude | 4.0 | ||
Date-Time |
Sunday, May 25, 2003 at 07:32:32 (UTC) - Coordinated Universal Time Sunday, May 25, 2003 at 01:32:32 AM local time at epicenter Time of Earthquake in other Time Zones |
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Location | 43.08N 101.84W | ||
Depth | 5.0 kilometers | ||
Region | SOUTH DAKOTA | ||
Reference |
60 km (35 miles) E of Pine Ridge, South Dakota 90 km (55 miles) SSW of Kadoka, South Dakota 100 km (60 miles) ENE of Chadron, Nebraska 185 km (115 miles) SW of PIERRE, South Dakota |
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Location Quality | Error estimate: horizontal +/- 14.6 km; depth fixed by location program | ||
Location Quality Parameters |
Nst=19, Nph=20, Dmin=212.2 km, Rmss=1.43 sec, Erho=14.6 km, Erzz=0 km, Gp=112.6 degrees | ||
Source | USGS NEIC | ||
Remarks | Felt (IV) at Kyle, Martin and Porcupine; (III) at Pine Ridge. Also felt (IV) at Gordon and (III) at Chadron, Nebraska. |
EARTHQUAKES IN THE STABLE CONTINENTAL REGION
Earthquakes east of the Rocky Mountains, although less frequent than in the West, are typically felt over a much broader region. East of the Rockies, an earthquake can be felt over an area as much as ten times larger than a similar magnitude earthquake on the west coast. A magnitude 4.0 eastern U.S. earthquake typically can be felt at many places as far as 100 km (60 mi) from where it occurred, and it infrequently causes damage near its source. A magnitude 5.5 eastern U.S. earthquake usually can be felt as far as 500 km (300 mi) from where it occurred, and sometimes causes damage out to 40 km (25 mi).
FAULTS
At well-studied plate boundaries like the San Andreas fault system in California, often scientists can determine the name of the specific fault that is responsible for an earthquake. In contrast, east of the Rocky Mountains this is rarely the case. All parts of this vast region are far from the nearest plate boundaries, which, for the U.S., are to the east in the center of the Atlantic Ocean, to the south in the Caribbean Sea, and to the west in California and offshore from Washington and Oregon. The region is laced with known faults but numerous smaller or deeply buried faults remain undetected. Even most of the known faults are poorly located at earthquake depths. Accordingly, few earthquakes east of the Rockies can be linked to named faults. It is difficult to determine if a known fault is still active and could slip and cause an earthquake. In most areas east of the Rockies, the best guide to earthquake hazards is the earthquakes themselves.
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Did You Feel It?
Theoretical P-Wave Travel Times Earthquake Information for SOUTH DAKOTA Earthquakes: Frequently Asked Questions
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NB:
The region name is an automatically generated name
from the Flinn-Engdahl (F-E) seismic and geographical regionalization scheme.
The boundaries of
these regions are defined at one-degree intervals and therefore differ from
irregular political boundaries.
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