The question many people asked after the magnitude 8.7 March 28, 2005, earthquake was "Why wasn't there a tsunami?" The area is 200 km west of Sibolga, Sumatra, or 1400 km northwest of Jakarta, roughly halfway between the islands of Nias and Simeulue. A great earthquake was noted at 23:09:36 hrs, local time at epicentre, on Monday, March 28, 2005.
Have any problems using the site? To start with, there was a tsunami generated by this earthquake, which is clearly evident from most tide-gauge stations throughout the Indian Ocean … The magnitude was 8.7 on the Richter scale and located in NORTHERN SUMATRA, INDONESIA. Questions?Data collected over the subduction zone offshore of Sumatra, Indonesia, has enabled the top of the downgoing plate to be mapped across a long-lived segment boundary at one end of the rupture zone. They note that the high probably originated at the Wharton fossil ridge, and is almost aseismic in both local and global data sets, suggesting that while the region around it may be weakened by fracturing and fluids, the basement high locally strengthens the plate boundary, stopping rupture propagation.Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. This improved understanding will greatly aid global efforts to provide accurate tsunami warnings and hazard assessments. A 3-km high on the top of the plate over a 15-km by 30-km region matches where the 2005 earthquake rupture stopped. Seismic recordings give the earthquake a magnitude of about 8.7, and effects were felt as far away as Bangkok, Thailand, a distance of 1000 km .
Furthermore, analysis of these two earthquakes and comparison with historical earthquakes of similar magnitude (M > 8.5) will allow us to better forecast future variations in tsunami runup. The epicentre was located 90 km south of Sinabang with 30 Km Depth 2.065 N 97.010 E The ultimate goal is to save lives and reduce property damage from future tsunami disasters. All the details of the earthquake that occurred, Earthquake off the west coast of northern Sumatra. Knowledge gained from these important earthquakes will help us to provide more detailed tsunami-propagation simulations. A great earthquake with a Moment Magnitude 8.7 struck off the coast of Western Sumatra just south of the region where the great earthquake of 26 December 2004 (Moment Magnitude 9) triggered a devastating tsunami which left about 300,000 people dead or missing in nearly a dozen nations in Africa and Southeast Asia. Seismic reflection data, similar to that used to find oil reserves, gives a detailed image of the shape of the downgoing plate. The topographic high appears to strengthen the plate boundary, and only very large earthquakes would break through this barrier.New geophysical data show that fault slip during the March 2005 magnitude 8.7 (Mw) earthquake off the west coast of northern Sumatra, Indonesia (also referred to as the Simeulue-Nias earthquake), was stopped by the topography on the downgoing plate.Earthquakes in subduction zones, where one tectonic plate is forced beneath another, usually break only a part of the plate boundary fault. Or view hourly updated newsfeeds in your RSS reader: Keep up to date with the latest news from ScienceDaily via social networks:Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Earthquakes. All the details of the earthquake that occurred, Earthquake off the west coast of northern Sumatra. The pieces that break independently are known as segments. New geophysical data show that fault slip during the March 2005 magnitude 8.7 (Mw) earthquake off the west coast of northern Sumatra, Indonesia (also … Magnitude Range ≥ 5.0 ANSS Comcat ; Tectonic Summary.
In that report, Dr. Richard Meehan of Stanford University concluded that the “Dairi Mine is located in one of the highest risk areas in the world,” near the Sumatra subduction megathrust which produced in 2004 and 2005 earthquakes of magnitude 9 and 8+ respectively. The March 28, 2005, M 8.6 northern Sumatra, Indonesia, earthquake occurred as the result of thrust faulting on the interface of the Australia plate and Sunda plate and was caused by the release of stresses that develop as the Australia plate subducts beneath the overriding Sunda plate. Topography on the top of the downgoing plate has often been suggested a cause of this segmentation, but there are few examples where this topography is as well-known as well as the details of earthquake rupture.This survey by Timothy Henstock and colleagues spans a complex segment boundary zone between the southern termination of the Mw 8.7 earthquake and the northern termination of a major 1797 earthquake that was partly filled by a Mw 7.7 event in 1935. They have identified an isolated 3 km basement high at the northern edge of this zone, close to the 2005 slip termination. ... 3/2/2005 8:13:32 AM UTC.