Reoccurrence of extreme geophysical events in IndonesiaRon Harris Dutch historical records document several extreme geophysical events in the Indonesian region over the past 400 years. These events have only recently begin to reoccur and pose a significant threat to this densely populated region. The record includes extreme earthquake and tsunami events in eastern Indonesia from 1629 to 1852, in the Sumatra region during the 1800's and extreme eruptions of Tambora and Krakatoa. The Toba volcanic center is also in this region, which may have nearly extinguished the entire human race around 73 Ka. The extreme events during the past 400 years account for around 200,000 deaths and global effects on climate. However, the reoccurrence of just a few of these events during the 21st century has already claimed more than 300,000 lives. The historical record we have compiled also informs us of an increasing threat of strain accumulating in the eastern Indonesia region over the past 160 years. Several extreme geophysical events are recorded in this region that inflicted heavy damage at dutch out-posts in both Banda Neira and Ambon in 1629 (15 m wave), 1674 (2 m wave), 1710, 1754, 1778, 1802 and 1852 (8 m wave). Since this time only one shallow earthquake of > Mw 8 is documented. The quiescence of mega-thrust seismicity in the region over the past 160 years is a stark contrast to the high rate of tsunamigenic earthquake activity from 1629-1852. It is highly likely that more tsunamigenic earthquakes are immanent in the eastern Indonesian region. We advise the coastal cities in this region to immediately take actions to reduce the disaster potential of future tsunami. |
