At 10:54 a.m. on February 28, 2001, a deep earthquake centered near the Nisqually Delta northwest of Olympia startles the entire Puget Sound region and causes more than $1 billion in damage to area buildings and roads. Dangerous ground: Hard lessons learned since the 2001 ... in the last 10 years since the Nisqually earthquake that really has some ... when the shaking is not dampened by distance or depth.
The epicenter of the February 28, 2001 magnitude 6.8 Nisqually earthquake was located near the center of this map at a depth of 52km. It is the significantly shallower depth that was the main reason for the stronger ground shaking felt in Los Angeles, even though the earthquake north of Seattle was technically larger (M6.8 versus M6.7). A magnitude 6.8 earthquake struck southern Puget Sound (see map below) on February 28th, 2001, causing an estimated $0.7 to $1.4 billion in damages to the surrounding area. The distance across the image is approximately 10.5km.
Fault Parameters of the Nisqually Earthquake Determined from Moment Tensor Solutions and the Surface Deformation from GPS and InSAR by Amanda Bustin, Roy D. Hyndman, Anthony Lambert, John Ristau, Jiangheng He, Herb Dragert, and Marco Van der Kooij Abstract The magnitude 6.8 Nisqually earthquake occurred on 28 February 2001 at a depth of 50–60 km within the subducting Juan de …
The surrounding land image is a USGS DOQ. The multibeam bathymetry data was collected 23 days after this earthquake. The Nisqually earthquake occurred along a subduction zone at depths between 30 and 36 miles whereas the Northridge earthquake was on a transform (and blind) fault at a depth of 3 to 11 miles. The Northridge earthquake had a hypocentral depth of 18 kilometers (11 miles), deep for a California earthquake, but considered shallow compared to other regions. The Nisqually earthquake had a depth of some 52 kilometers (33 miles), meaning that no building experienced greater shaking than would be expected at a distance of 52 kilometers from a magnitude 6.8 earthquake. Event Name: Nisqually, Washington Earthquake Event Date: 02/28/2001, 18:54 UTC, (10:54 AM PST) Event Identification: 20010228_1 Recorder Type: ETNA, K2, MT WHITNEY, SMA-1 The low ground accelerations associated with the Nisqually earthquake did not approach the design level of buildings designed to comply with the 1997 Uniform Building Code mainly because the ground accelerations and the of strong ground shaking was low Shake Map: Instrumental Measurements of Shaking Intensity Community Internet Intensity Map: …
Centered a mere 17.8 kilometers northeast of Olympia, at a depth of 52 kilometers, the earthquake caused considerable damage to the Legislative Building and surrounding structures. Lessons from the Nisqually quake that shook Pacific Northwest 19 years ago.
The Nisqually earthquake was an intraslab earthquake, occurring at 10:54 a.m. PST (18:54 UTC).
2001-02-28 18:54:32 (UTC) | 47.149°N 122.727°W | 51.8 km depth
Location 47.1525N 122.7197W 17.6 km NE of Olympia, WA 23.7 km WSW of Tacoma, WA 57.5 km SSW of Seattle, WA Name of data file: 01022818543p SHAKING INTENSITIES.