U.S. Geological Survey       National Strong-Motion Program

Event Name: Markleeville, California Earthquake
Event Date: 09/26/2000 07:20 UTC (09/26/2000 00:20 am PDT)
Event Identification: 20000926_1
Recorder Type: ETNA

Data Organization and Format ||  Downloads (updated 01/19/2001) ||  Tables (updated 01/19/2001

Data Organization and Format

The September 26, 2000, 07:20 UTC Mw 4.5 Markleeville, California Earthquake data recorded by the USGS National Strong-Motion Network (NSMN) are available via the NSMP ftp server in the folder (directory) "20000926_1" (ftp://smftp.wr.usgs.gov/20000926_1).  The time series provided are available in uncorrected acceleration, corrected acceleration, corrected velocity, corrected displacement, response spectra (relative displacement, relative velocity, pseudo-velocity, and absolute acceleration), and Fourier amplitude spectra of corrected acceleration.  All of the data are in SMC format.

In a departure from previous file-naming conventions (where for a particular channel the different the time series data all had the same filename, and thus required separate directories for each data type), the file names for the data have the following form:

uncorrected acceleration: RRRRc_u.smc
corrected acceleration: RRRRc_a.smc
corrected velocity: RRRRc_v.smc
corrected displacement RRRRc_d.smc
response spectra: RRRRc_r.rs2
Fourier amplitude spectra (f): RRRRc_f.fs1

where 'RRRR' is the four-digit recorder serial number (including leading 0's), 'c' is the channel number of the recorder ('a' corresponds to channel 1, 'b' to channel 2 , etc), the '_x' is used to identify the data type, and the suffix refers to the data format (rs2 and fs1 are valid SMC format types recognized by the BAP processing program.

The data are stored in two directories: uncorrected (only uncorrected acceleration) and corrected (all of the corrected and processed data, including acceleration, velocity, displacement, response spectra and Fourier amplitude spectra. This convention for organizing the data was implemented to avoid confusion between the directory names (Vol1, Vol2, … Vol6) previously used for some earlier events and the standard conventions for Volume1, Volume2 and Volume 3 processing.

Information on how the data are processed can be found in the section on DATA PROCESSING.


To facilitate downloading the data, the data have been compressed into a PC compatible ".zip" format.  The zip file is located in the "zips" folder in "20000926_1/" on the NSMP ftp server, "ftp://smftp.wr.usgs.gov/20000926_1".

Files of uncorrected acceleration and corrected acceleration, velocity, and displacement for Episensors sensors were corrected for a polarity reversal error discovered in the original data. The Fourier amplitude and response spectral data are unaffected by this correction." .  Users who downloaded data before 01/19/2001 should download the data set again.


20000926_1_all.zip     uncorrected and corrected (0.5 Mb; uncompresses to 1.5 Mb; updated 01/19/2001)


List of corrected peak ground accelerations and velocities for time-series data, updated 01/19/2001 (click here to obtain list as Excel spreadsheet)

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This page was updated on January 19, 2001.