The layers of the earth课件.ppt

The interior of the Earth Lindalee790433159@ ;The interior of the Earth, like that of the other terrestrial planets, is divided into layers by their chemical or physical (rheological) properties.;The Crust:The outer layer of the Earth is a chemically distinct silicate solid crust, which is underlain by a highly viscous solid mantle. ;The crust is separated from the mantle by the Mohorovi?i? discontinuity, and the thickness of the crust varies: averaging 6 km under the oceans and 30–50 km on the continents. Earths crust occupies less than 1% of Earths volume.;The Mantle: The Earths mantle is an about 2,970 km thick (~1,800 mi) rocky shell that constitutes about 84 percent of Earths volume and about 2/3 of the planet’s mass. It is divided into sections based upon results from seismology. ;These layers (and their depths) are the following: the upper mantle (33–410 km), the transition zone (410–660 km), the lower mantle (660–2891 km), and in the bottom of the latter region there is the anomalous D layer with a variable thickness (on average ~200 km thick).;The Core: The core is separated from the mantle by the Gutenbery discontinuity. It’s about 3473 km thick and occupies 16.3% of the earth’s volume and 1/3 of the planet’s mass. Based on the seismic wave velocity, the core is divided into two layers. ;The outer core begins about 2900KM below the surface and about 2,250KM thick. And depth of the solid inner core is about 5150KM. Both layers of the Earths core are made up of iron and nickel. Temperature reaches 2200/C to 5000/C in the outer core 5,000/C in the inner core .;The outer layers of the earth;Atmosphere HydrosphereBiosphere;一、地球的内部圈层;想一想：有什么办法可以了解一只熟鸡蛋的内部构造呢？;33;圈层名称;思考、探究：;二、地球的外部圈层;1、大气圈;2、水圈;;1、横波在到达地核时完全消失，这是因为：（ ） A、组成地核的物质为固态 B、外核的物质接近液态 C、内核的物质接近气体 D、横波的传播速度比纵波慢 2、地壳的平均厚度为：（ ） A、 6 千米 B、17 千米 C、 33千米 D、56千米;读“某地地震波速度随深度的变化图”，完成：;; 想一想： ①地壳的厚度是否各处一样？ ②为了探测莫霍界面的情况进行的地震波测定，哪里最迟得到从莫霍界面传来地震波？;活动