Satellite Thermal anomalies before the M S 7.1 New Zealand Earthquake 2010 Qin Kai Wu Lixin Guo Guangmeng 2011 IGARSS, 27 July 2011 • Vancouver
<ul><li>Background </li></ul><ul><li>Data and result </li></ul><ul><li>Physical mechanism </li></ul>Outlines
The first report of earthquake thermal anomalies is represented by Gazli earthquake March 19, 1984 (M=7.2). Thermal IR image of 11.03.1984, one week before the earthquake - At the point of the intersection of the Tamdy-Tokraus and Karatau faults Background Satellite Thermal IR anomalies
Background Source: S. A. Pulinets, D. Ouzounov, (2006), Thermal, atmospheric and ionospheric anomalies around the time of the Colima M7.8 earthquake of 21 January 2003, Annales Geophysicae (2006) 24: 835 - 849. Sharp increase in the daytime temperature from the epicenter for the middle of January (about one week before the earthquake).
Background Qin Kai 2010: Surface latent heat flux (SLHF) anomaly before the Apr 14, 2010 M S 7.1 Yushu earthquake
Background According to the New Zealand GNS Science, a M S 7.1 earthquake happened on the South Island of New Zealand ( 43.52°S, 172.17°E ) UTC on Sept. 3, 2010. It a result of strike-slip faulting as the Pacific and Australia plates interact in the central South Island.
Data and result <ul><li>Two thermal parameters: </li></ul><ul><li>Skin temperature refers to the temperature of the surface layer of the earth. </li></ul><ul><li>SLHF can reflect water and heat exchange between the ground surface and the atmosphere, as a result of the heat absorbed or released by phase transitions (condensation, evaporation or melting) of atmospheric moisture. </li></ul>
Data and result Both of the two thermal parameters are from NCEP/NCAR assimilation data. it is generated by an analysis technique in which multi-source observations such as land surface, ship, pibal, aircraft, satellite, and other sensors are accumulated into the model state by taking advantage of consistency constraints with the laws of time evolution and physical properties.
Data and result A spot-shaped SLHF anomaly with a high value to the northeast of the epicenter on Aug. 1, 2010.
Local high-temperature anomalies of 3 – 6°C had appeared (the geothermal areas northeast of the epicenter, at the center of the North Island and in the southwestern South Island) on July 31 and Aug. 1, 2010. Data and result
If the thermal anomaly was only a meteorological effect ? Data and result
Observations of the weather stations showed that near the thermal anomalies area there were just low-speed relatively-stable winds Data and result
Infrared satellite cloud map of FY-2D satellite showed that the weather conditions were mainly sunny with sporadic haze distributions Data and result
So, the local thermal anomalies on July 31 and Aug. 1 resulted neither from solar radiation enhancement of the reduced cloud (e.g., cloudy to clear), nor from a warm air mass effects, but rather most likely resulted from underground heat. Data and result
Data and result The N-S displacement components of GPS stations in New Zealand recorded a quasi-synchronous fluctuation on July 31 and Aug. 1 2010. This is consistent with the time of the thermal anomalies, and reflects tectonic activity enhancement before the earthquake.
Physical mechanism New Zealand is located on the tectonic plate boundary between the Australian and Pacific plates. The oblique collision of the two plates causes the Pacific Plate to subduct be neath the Australian Plate , which form s a h igh -temperature and h igh -pressure zone in the lithosphere.
Physical mechanism The subduction process provides sufficient energy for hot material to upwell from mantle, which leads to abundant geothermal activity such as hot springs and volcanoes.
<ul><li>First, the long-term tectonic activity in the interface region between the Pacific and Australian plates was enhanced in the latter period of the seismogenic process, leading to rock expansion and crack propagation in the local subduction zone and hence providing abundant channels for hot material upwelling from the deep crust and mantle. </li></ul><ul><li>Second, hot material resulted in the gradual expansion of the region and then caused local temperatures to increase in particular zones, which are connected with subsurface fluids. </li></ul><ul><li>Third, the surface temperature increment affected change in the difference between the specific humidity of the ground and the overlying surface air masses, hence resulting in local SLHF increases. </li></ul> Physical mechanism
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