The Pacific Northwest Seismograph Network PNW EARTHQUAKE INFORMATION Strong Motion Information

Magnitude	Date	Latitude	Longitude	Depth
6.8	2001/02/28 18:54 UTC	47.1525	-122.7197	52.40

Contents

Maps

Shake Map Instrumental Intensity, peak accelerations, peak velocities.

Strong Motion Parameters

Strong Motion Parameters for each component of each station

STA	COMP	Dist (km)	PGA (%g)	Dur_BB (sec)	Dur_rel (sec)	AI (cm/sec)	SI(5%) (cm)	PGV (cm/sec)	F_d (Hz)	BW (Hz)
UPS	ELE	22	5.5066	2.0	46.2	7.7806	27.8829	7.4585	2.1	0.4
UPS	ELN	22	6.0686	0.0	44.1	8.4320	23.1818	5.6492	3.0	0.2
UPS	ELZ	22	5.4854	6.2	48.8	6.3077	11.8362	2.4324	5.3	0.4
PCFR	ELE	28	11.0287	1.9	17.7	34.8804	53.4458	13.1767	2.6	0.2
PCFR	ELN	28	13.0824	1.7	17.0	31.7595	26.9273	7.0978	5.8	0.3
PCFR	ELZ	28	14.0885	0.3	16.5	31.3803	20.0063	4.1459	3.6	0.2
TBPA	ELE	29	6.3899	0.0	67.7	22.0416	50.5839	10.8881	0.5	0.4
TBPA	ELN	29	6.4892	0.0	69.5	25.3530	62.5490	9.2587	0.5	0.6
TBPA	ELZ	29	4.6574	0.0	81.2	8.5340	27.9131	5.1942	0.6	0.2
PCEP	ELE	33	20.3869	0.0	13.2	50.7514	62.3902	13.4826	1.0	0.2
PCEP	ELN	33	21.3314	0.0	14.8	50.2009	33.0479	10.4620	6.4	0.2
PCEP	ELZ	33	15.4756	0.0	16.2	36.2579	27.4699	6.0600	5.3	0.2
KIMR	ELE	39	16.2800	0.0	17.8	26.0234	37.8660	9.5761	4.4	0.3
KIMR	ELN	39	15.0155	0.8	17.3	19.8104	30.4465	8.7221	2.2	0.6
KIMR	ELZ	39	7.0458	0.2	26.1	8.6336	19.7861	3.8006	0.9	0.4
PCMD	ELE	43	15.7629	0.0	13.1	30.3670	34.3362	9.4342	2.1	0.2
PCMD	ELN	43	11.0448	0.0	18.8	24.9427	24.8181	7.0103	4.0	0.2
PCMD	ELZ	43	6.7582	0.8	18.4	11.8252	11.0686	3.5916	4.0	0.4
RBEN	ELE	51	10.9706	0.0	28.3	11.9759	40.4749	8.2590	2.2	0.2
RBEN	ELN	51	10.9340	0.0	18.5	13.3868	30.5762	7.4443	2.2	0.3
RBEN	ELZ	51	4.5480	0.0	33.6	5.0866	11.9717	2.8960	1.4	0.2
TKCO	ELE	53	27.2808	0.0	14.5	76.5972	73.8518	21.8842	1.8	0.2
TKCO	ELN	53	17.0435	0.0	20.1	47.8693	48.6775	13.5065	1.9	0.4
TKCO	ELZ	53	7.7742	0.1	24.4	14.2881	23.8524	6.6995	2.3	0.3
MPL	ELE	54	9.7708	0.6	15.2	15.4326	39.3606	7.3443	1.4	0.2
MPL	ELN	54	8.1218	0.0	17.5	14.5271	31.9881	7.7945	1.8	0.2
MPL	ELZ	54	4.9519	0.0	27.1	4.9377	15.0441	3.5493	1.4	0.2
KIMB	ELE	57	13.5246	0.2	19.8	21.6089	68.9304	18.2652	1.5	0.3
KIMB	ELN	57	9.2460	0.0	28.6	11.0578	40.9165	10.9508	0.8	0.2
KIMB	ELZ	57	4.7102	0.0	35.0	5.0999	29.2422	7.0607	0.7	0.2
SP2	ELE	57	30.7736	0.0	7.4	83.4597	65.5113	20.1153	3.3	0.5
SP2	ELN	57	18.9968	0.0	12.1	35.4717	37.1883	13.2044	2.3	0.2
SP2	ELZ	57	11.7024	0.0	20.0	11.4725	18.0597	5.6010	2.7	0.3
KITP	ELE	59	4.8238	0.0	43.9	8.7161	31.3506	5.6193	0.6	0.3
KITP	ELN	59	4.9300	0.0	35.3	9.3654	33.0717	7.4803	0.8	0.2
KITP	ELZ	59	2.6688	0.0	45.9	3.8466	19.5049	5.2385	0.7	0.3
RHAZ	ELE	59	4.5409	0.0	17.0	3.2544	16.9083	4.1628	4.0	0.2
RHAZ	ELN	59	3.9331	0.0	23.6	3.2653	13.3309	4.4836	3.5	0.3
RHAZ	ELZ	59	3.6510	0.0	23.5	2.1631	7.9753	1.7393	6.7	0.2
QAW	ELE	60	10.4653	8.0	33.2	25.2027	41.5300	8.3897	0.6	0.3
QAW	ELN	60	11.4009	0.0	30.5	31.7063	41.4740	11.8705	1.6	0.3
QAW	ELZ	60	7.6529	0.0	31.5	19.0055	32.7888	6.3960	3.6	0.2
LAWT	ELZ	61	3.1850	0.0	70.8	3.7718	11.9186	2.2116	0.8	0.3
LAWT	ELN	61	5.5567	0.0	29.4	9.2892	35.1316	7.6220	0.9	0.2
LAWT	ELE	61	6.5295	0.0	28.0	9.1919	33.8139	8.8135	0.6	0.2
RAW	ELE	63	17.2692	0.0	9.7	36.9901	75.9169	16.9713	0.9	0.2
RAW	ELN	63	12.4685	0.0	13.9	22.3245	37.9986	10.6601	2.0	0.2
RAW	ELZ	63	5.5912	0.6	21.6	7.6175	15.7653	4.3713	5.2	0.2
WISC	ELE	65	11.3350	0.0	23.7	17.1864	30.1877	10.1150	4.0	0.3
WISC	ELN	65	9.4362	0.0	33.8	12.1662	30.0603	6.6778	1.1	0.2
WISC	ELZ	65	3.4447	0.0	64.8	4.0395	14.5205	3.0764	0.6	0.6
RWW	BHE	66	5.8046	7.1	38.4	6.4278	10.7126	1.3823	3.4	0.3
RWW	BHN	66	5.6421	1.6	35.7	6.2275	9.8324	1.2256	4.3	0.2
RWW	BHZ	66	5.2630	0.0	41.7	2.3168	10.0665	1.2955	0.6	0.5
KINR	ELE	67	7.5468	0.0	44.4	8.4021	23.5308	4.9980	0.6	0.3
KINR	ELN	67	4.9383	0.0	38.0	9.2545	28.6148	6.5310	0.8	0.3
KINR	ELZ	67	3.1434	0.0	45.6	3.5842	15.5297	2.7611	0.9	0.4
NOWS	ELN	69	8.7706	0.0	35.5	15.2779	38.0087	9.8338	0.9	0.3
NOWS	ELZ	69	2.9167	0.0	60.6	4.4546	18.6252	3.7699	1.4	0.2
BRKS	ELE	75	7.7101	0.0	37.6	20.2678	34.9845	7.6893	1.7	0.3
BRKS	ELN	75	10.3843	0.0	36.0	30.0104	47.7886	10.9947	0.9	0.2
BRKS	ELZ	75	4.5837	0.0	47.1	6.7591	14.0431	2.4127	1.7	0.3
ELW	ELE	75	5.6345	1.5	20.6	5.4143	15.6307	4.1192	2.0	0.3
ELW	ELN	75	5.5387	0.0	19.6	5.9295	15.4204	4.0568	2.0	0.2
ELW	ELZ	75	3.4791	0.0	26.4	2.2713	10.7612	2.5077	0.9	0.2
LEOT	ELE	82	6.3702	0.0	37.8	8.3590	22.8791	6.3091	3.4	0.2
LEOT	ELN	82	7.5394	0.0	46.1	7.0044	19.6456	4.5621	0.6	0.4
LEOT	ELZ	82	3.9979	0.0	48.0	4.0802	11.9397	2.5002	6.2	0.2
BEVT	ELE	92	4.8711	0.0	43.6	3.3237	15.7072	3.4934	1.9	0.4
BEVT	ELN	92	4.9543	0.0	41.4	3.3852	14.8999	4.4564	3.3	0.2
BEVT	ELZ	92	2.2583	0.0	61.5	1.7747	10.2478	2.0523	0.8	0.3
MBPA	ELE	104	12.0099	0.0	11.5	13.4168	13.2872	5.2956	4.3	0.2
MBPA	ELN	104	15.4664	0.0	7.7	19.3730	12.1860	4.8905	4.3	0.5
MBPA	ELZ	104	4.9960	0.0	19.2	3.4631	5.0836	1.4898	10.7	0.3
SQM	BHE	106	1.9576	0.0	36.9	0.4736	6.1177	1.1260	0.8	0.2
SQM	BHN	106	1.3091	0.0	43.5	0.3285	4.6103	1.1531	2.0	0.2
SQM	BHZ	106	1.0024	0.0	43.9	0.2180	3.9056	0.8925	0.9	0.2
ALST	ELE	119	6.0839	0.0	17.7	6.5777	16.9141	4.8109	2.3	0.2
ALST	ELN	119	7.5772	0.0	14.9	11.5030	19.1053	5.1293	3.0	0.2
ALST	ELZ	119	2.3699	0.0	35.7	1.4366	6.4620	1.7748	3.6	0.4
ERW	ELE	145	0.9461	0.0	29.5	0.1412	2.5539	0.8639	1.6	0.4
ERW	ELN	145	0.8498	0.0	41.6	0.1151	2.8300	0.6474	0.8	0.3
ERW	ELZ	145	0.8471	0.0	42.6	0.0751	3.0352	0.7151	0.9	0.3
ERW	HHE	145	0.9507	0.0	29.6	0.1389	2.5259	0.8889	1.6	0.4
ERW	HHN	145	0.7971	0.0	41.7	0.1036	2.6802	0.5869	0.8	0.3
ERW	HHZ	145	0.7997	0.0	43.4	0.0735	2.9361	0.6414	0.9	0.3
ROSS	ELE	166	1.8721	0.0	43.4	1.0632	5.1419	1.2357	2.1	0.2
ROSS	ELN	166	2.5431	0.0	51.9	1.1694	5.4975	1.2719	2.7	0.2
ROSS	ELZ	166	1.3269	0.0	71.5	0.4757	3.5776	0.6439	3.6	0.3
KEEL	ELE	179	1.4429	0.0	72.6	1.0790	12.7645	2.3138	0.5	0.3
KEEL	ELN	179	1.3636	0.0	75.6	1.0068	10.9662	1.8225	0.5	0.3
KEEL	ELZ	179	0.7195	0.0	72.6	0.2653	4.6601	0.9027	1.1	0.2
SBES	ELE	181	0.6301	0.0	41.8	0.1327	2.8173	0.6421	2.1	0.8
SBES	ELN	181	0.5017	0.0	41.3	0.1085	2.6189	0.5225	1.2	1.1
SBES	ELZ	181	0.4800	0.0	51.2	0.0585	1.7203	0.3448	2.0	0.3

Parameter Definitions

• STA - The 3 letter station designation. Station locations are shown in the map and are listed in a station table.
• COMP - Component flag. Each station has a tri-axial accelerometer for measuring motions in the vertical (Z), north-south (N) , and east-west (E) directions. The "EL" part of the component indicates that the data are from an accelerometer with a high sample rate (here 100 samples per second). A "BH" or "HH" indicates that the data are from a broadband velocity sensor. (The "HH" components usually have a 100 sps sample rate and the "BH" components are usually 40 or 50 sps).
• Dist - Surface distance from the earthquake epicenter to the recording station.
• PGA - Peak ground acceleration. The peak value from a single component (no vector sums). Note that these values are expressed in scientific notation. As an example, a value of 5.1e-02 means 5.1 x 10^(-02) = 5.1 x 0.01 = 0.051 meaning 5.1%g or 51 milli-g.
• Dur_BB - The Bolt-bracketed duration is the measure of time between the first and last exceedence of 0.05 g's. A listed value of 0.0 indicates that the ground motion never exceeded the 0.05g threshold.
• Dur_rel - The relative duration does not depend on the peak values. It is the time interval between the points at which 0.05% and 0.95% of the total energy has been recorded.
• AI - The Arias Intensity is a measure of the total energy at the recording station and is proportional to the sum of the acceleration squared. It is defined as pi/(2g) * dt * sum(a[n]*a[n]), where dt is the sample interval and a[n] is the nth acceleration value.
• SI - The Spectrum Intensity for 5% damping. It is defined as the integral of the psuedo-Spectral velocity curve (also known as the velocity response spectrum), integrated between periods of 0.1 - 2.5 seconds. These quanitities are motivated by the need to examine the response of structures to ground motion. Structures are modeled with a sequence of harmonic oscillators with 5% viscous damping and having varying natural frequencies. The ground motion is used as a forcing function on the oscillators and the resulting displacement is calculated. The peak displacement and natural period of each oscillator form a data point for the Spectral Displacement curve. Multiplying each data point by omega (2 * pi / natural_period ) gives the psuedo-Spectral Velocity curve, or the velocity response spectrum.
• PGV - Peak ground velocity; determined by integrating the acceleration time-series using the trapezoidal rule.
• F_d - Dominant frequency of ground motion; defined as the frequency corresponding to the peak value in the amplitude spectrum. Thus, F_d indicates the frequency for which the ground motion has the most energy. The amplitude spectrum has been smoothed before determining F_d and BW.
• BW - Bandwidth of the dominant frequency; measured where the amplitude falls to 0.707 (1 / square root of 2) of the amplitude of the dominant frequency. Again, this is based on a smoothed amplitude spectrum.

Station Information

List showing station coordinates and sensor information.
Station Maps

The information presented in this document is preliminary. It will be modified after additional analysis of the accelerograms.

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