👉 National Geophysical Data Center in the context of 2006 Yogyakarta earthquake
The 2006 Yogyakarta earthquake (also known as the Bantul earthquake) occurred at 05:53 local time on 27 May with a moment magnitude of 6.4 and a maximum MSK intensity of VIII (Damaging) in the Yogyakarta region of Java, Indonesia.
Several factors led to a disproportionate amount of damage and number of casualties for the size of the shock, with more than 5,700 dead, tens of thousands injured, and financial losses of Rp 29.1 trillion ($3.1 billion). With limited effects to public infrastructure and lifelines, housing and private businesses bore the majority of damage (the 9th-century Prambanan Hindu temple compound was also affected), and the United States' National Geophysical Data Center classified the total damage from the event as extreme.Although Indonesia experiences very large thrust earthquakes offshore at the Sunda Trench, this was a large strike-slip event that occurred on the southern coast of Java near the city of Yogyakarta. Mount Merapi lies nearby, and during its many previous historical eruptions, large volume lahars and volcanic debris flowed down its slopes where settlements were later built. This unconsolidated material from the stratovolcano amplified the intensity of the shaking and created the conditions for soil liquefaction to occur. Inadequate construction techniques and poor quality materials contributed to major failures with unreinforced masonry buildings (then the most prevalent type of home construction), though other styles fared better.
National Geophysical Data Center in the context of Terrain
Terrain (from Latinterra'earth'), alternatively relief or topographical relief, is the dimension and shape of a given surface of a land. In physical geography, terrain is the lay of the land. This is usually expressed in terms of the elevation, slope, and orientation of terrain features. Terrain affects surface water flow and distribution. Over a large area, it can affect weather and climate patterns. Bathymetry is the study of underwater relief, while hypsometry studies terrain relative to sea level.
The model consists of a degree and order 12 spherical harmonic expansion of the magnetic scalar potential of the geomagnetic main field generated in the Earth's core. Apart from the 168 spherical-harmonic "Gauss" coefficients, the model also has an equal number of spherical-harmonic secular variation coefficients predicting the temporal evolution of the field over the upcoming five-year epoch.
