4.9 km SSE of Seattle
     9.8 km  SW of Bellevue
    15.6 km SSW of Kirkland, Wa

This earthquake is of interest because of its shallow depth and thrust-type fault mechanism on an apparently east-west oriented fault. It occurred within a broad fault zone known as the Seattle fault. See also, the discussion on the magnitude 5 Point Robinson earthquake that occurred on January 29, 1995 that may also have been related to the Seattle fault.

The M 3.5 February 9, 1997 earthquake was followed by a smaller (magnitude 2) aftershock about 12 minutes later.

Name of data file: 97021004264p

This is a semi-automated web page produced after a significant earthquake to give essential information about the earthquake and previous earthquake activity in the region. This information will be updated as needed.

• A regional map showing the location of the earthquake.
• A Intermediate scale map showing the location of the earthquake and prior historical earthquakes with magnitude 3.5 or greater.
• A list of 10 big earthquakes preceding the mainshock that are closest to it and have a magnitude greater than 3.5. These are the most significant historical earthquakes in the vicinity of the mainshock (see intermediate scale map above).
• A map (Black and white) showing the location of the earthquake relative to cities.
• A map (Black and white) showing the location of the earthquake relative to the nearest seismograph stations that recorded it.
• A detailed list of all earthquakes (M > 1.0) that occurred in the vicinity of the special earthquake in the previous two years. For the locations of these events see the next map.
• A map of all earthquakes (M > 1.0) that occurred in the two years prior to the special earthquake. Detailed area shown is just few kilometers around the mainshock.
• A List of the nearest 20 strong motion sites
• A Seismogram recorded on the vertical component of broad-band station GNW. GNW is located on Green Mountain, near Gold Mountain on the Kitsap Peninsula. X-axis is time (trace is about 3.5 minutes in length), Y-axis is signal amplitude.
• A sample strong-motion accelerogram from a new experimental system at the U of W shows a maximum peak ground acceleration of 0.0004 g.

If sufficient P-wave first motion data are available, a fault plane determination for the earthquake will be available in the form of

• A diagram of the fault plane solution(s). In some cases more than one solution may fit the data.
• A table describing the fault plane solution(s) summarizing the characteristics of possible fault planes ("A" and "B") that are consistent with the recorded first-motion data.

Moment Tensor Estimates of the Earthquake size may also be available

• A Moment-Tensor Solution for this earthquake from Oregon State University
• A Moment-Tensor Web site at Oregon State University
• A Moment-Tensor Solution for this earthquake from University of Washington.