Data Services Newsletter

Volume 13 : No 1 : Spring 2011

DMS Data Products for the Tohoku, Japan Earthquake

Since its launch in February 2011, the DMC’s product management system, SPUD, has served tens of thousands of requests for Ground Motion Visualizations (GMVs) and Event Plots as well as various other data products. Following the Tohoku, Japan earthquake of March 11th, the demand for data products from SPUD was unprecedented. One month after the earthquake the GMV (Figure 1) for the main shock has been accessed over 26,700 times. The Event Plots (Figure 2) for the same event has been accessed over 8,500 times. These products were accessed from over 12,000 unique IP addresses indicating a very large number of people viewed the products from SPUD.

Snapshot of the Ground Motion Visualization for the March 11, 2011 Tohoku, Japan
Figure 1: Snapshot of the Ground Motion Visualization (GMV) for the March 11, 2011 Tohoku, Japan. The visualization shows the seismic
wavefield sweeping across USArray. Colors indicate vertical ground motion, while the tails indicate horizontal ground motion.
The title includes the region name and magnitude from the triggering NEIC earthquake alert, which were subsequently updated.

GMV and Event Plot product generation at the DMC is fully automated and is triggered by seismic event notifications received from the USGS NEIC. Following this trigger, the corresponding data is retrieved via the DMC’s web services, processed into final product form and submitted to SPUD. Without the need for human analysis or intervention, products can be generated any time of day and processing times are minimized. The GMV and Event Plot Suite were available from SPUD within 2-4 hours of the Tohoku earthquake; improvements to DMC systems will continue to reduce the time needed to produce the products.

Examples from the Event Plot suite for the March 11, 2011 Tohoku, Japan earthquake
Figures 2 a & b: Examples from the Event Plot suite for the March 11, 2011 Tohoku, Japan earthquake:
(a) global body wave record section and
(b) azimuth binned P-wave code stacks indicating a rupture duration of up to 200 seconds.

The demand for products in the hours after the quake initially exceeded SPUD’s capabilities. However, DMC staff members were able to react quickly, increasing the server’s capacity to meet the unprecedented demand. Interest in the data products for this event continued throughout the weeks following the quake.

Data products currently managed via SPUD include ANF Event Bulletins, WWSSN Film Chip images and IDA Calibration data as well as GMVs and Event Plot Suites. Upcoming products slated for inclusion in SPUD are USArray magnetotelluric transfer functions, solutions from the Global CMT Project and earthquake source-time functions.

For the current status of the DMC’s data product effort please visit http://ds.iris.edu/ds/products

by Rich Karstens and Chad Trabant (IRIS Data Management Center)

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