THE USE OF DST INDEX AS A PRECURSOR OF FIVE WORLD GREAT EARTHQUAKES WITH MAGNITUDE OF MORE THAN EIGHT

• Main Author: Agnesia Konom, Ekarista
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/70647
• Institution: Institut Teknologi Bandung

Earthquakes are natural disasters that have the potential to cause large losses. These disasters are frequent in the world but it is still difficult to accurately predict the time and place of earthquake events. Research on earthquake precursors has been conducted as part of disaster mitigation activities. One of them is by using the geomagnet index, namely the Dst index (disturbance storm time). This index shows significant anomalies and can be considered a precursor to earthquakes. To support anomalies in the Dst index, other geomagnet index data is used, namely the AE (Auroral Electrojet) index. The earthquake events used as the object of this study are the 2001 Arequipa (Peru) Earthquake, the 2004 Sumatra-Andaman Earthquake, the 2009 Samoa Earthquake, the 2011 Tohoku (Japan) Earthquake, and the 2015 Illapel (Chile) Earthquake. These earthquakes are the major earthquakes in the world with a magnitude of more than eight. This study showed that the magnitude of the anomalous value of each index was not related to the magnitude of the earthquake strength. However, earthquakes with a strength above 9 Mw have a faster range of anomalous appearances compared to earthquakes with a strength below 9 Mw. Based on the Dst and AE index curves, several significant anomalies were seen before the earthquake. The visible anomalous values vary widely from each earthquake and range from -63 nT to -387 nT for the Dst index and for the AE index ranging from 1137 nT to 3219 nT. The anomalies seen in the Dst index data correspond to the supporting data, namely the AE index so that it can be used to determine anomalies as precursors to earthquakes in each earthquake.