Warning in less than 5 minutes after August 8, M 7.6 Java earthquake

Yesterday's M 7.6 West Java earthquake was detected, located and sized after only 4 minutes and 38 seconds by the German Tsunami Early Warning System (GITEWS) currently under construction in Indonesia. The location of the earthquake has been established after just 2 minutes and 11 seconds. For comparison: The Pacific Tsunami Warning Center (PTWC) in Hawaii published the location and magnitude of this earthquake after about 17 minutes.

Such a rapid analysis was possible due to the new software system called “SeisComP” (Seismological Communication Processor) developed by GFZ Potsdam that was installed at the Meteorological and Geophysical Agency of Indonesia (BMG) in Jakarta, in the last weeks. BMG Jakarta will host the future Tsunami Early Warning Center for Indonesia, which is supported by the German government with 40 million Euro. SeisComP, with its functionality of standardized acquisition, global exchange and automatic as well as interactive analysis of earthquake data, forms the backbone of the Indian Ocean Tsunami Early Warning System.

Earlier SeisComP versions are in use with nearly 100 seismological observatories and organizations of the world. In the framework of the GITEWS project SeisComP was further improved to focus on accelerated manual analysis for early detection of potentially tsunamogenic large earthquakes. Sophisticated graphical user interfaces were developed for optimal display of automatic analysis results and for efficient interactive processing by operators at the warning centers. In Jakarta, the new version of the seismology software package “SeisComP3” replaces an older one that only worked automatically and did not include sufficient visual control and interaction. With the old version, earthquakes could be detected only after about ten minutes and localized relatively unprecisely. Furthermore the magnitude of strong quakes could only be determined to a certain degree. This older version was operational since 2005 as a immediate measure to support Indonesia after the devastating Sumatra tsunami in December 2004.

The work done at GFZ Potsdam and at BMG Jakarta is part of the installation of a Tsunami Early Warning System for the Indian Ocean region coordinated by GFZ Potsdam. Professor Reinhard Hüttl, Scientific Executive Board of GFZ Potsdam said: “Due to the German initiative and support, Indonesia has taken a large stride towards its self-defined goal of determining the location and size of large earthquake in less then 5 minutes. The new earthquake monitoring system is already running in real-time operation mode since May 2007 and has successfully detected and located a number of earthquakes. By the end of 2008 Indonesia will possess the most modern seismological network for tsunami early warning in the world.”

Good progress of GITEWS seismological network installation: nine of the planned 23 stations in Indonesia are already installed in Nias Island, Sumatra (2), Krakatau Island, Java (2), Kalimantan, Flores Island and Molucca Islands. Additional 5 stations are under preparation. The speed of installation strongly depends on various “non-scientific” factors like purchase of land, construction of seismic vaults and the current grounding of Indonesian airlines due to security considerations.

Quality versus quantity: Meanwhile, 63 additional seismological stations installed in Indonesia (45 Indonesian, 15 Japanese, 3 Chinese) are also acquired and analyzed by the SeisComP system. However, the data quality in many cases seems very poor and is not comparable to the high standards set for the GITEWS-stations.

The GITEWS-project is a contribution of the German Federal Government to re-establish the infrastructure in the disaster areas around the Indian Ocean affected by the 2004 Sumatra Tsunami. The project under the lead of GFZ Potsdam is carried by a consortium of eight German research institutes, four of these are Helmholtz centres.