Answer:
140 years is average duration of an earthquake.
Explanation:
- The Hayward fault is a geologic fault that is capable of massive destruction and is 119 km long fault western base of hills of San Francisco and is parallel to the San Andreas fault. The occurrence of an earthquake of 6.8 magnitudes in 1868 was biggest earthquake in California history.
- Recently various geologists have taken time interval of the past five large earthquakes and based on the past earthquakes data the interval of 140 years it will take to the formation of a large earthquake.
D. He was laughed at, at first
Explanation:
Serpentine
- Formation: it forms through serpentinization, a geological low-temperature metamorphic process where low-silica mafic and ultramafic rocks are oxidized and hydrolyzed with water into serpentinite.
- Characteristics: rich in magnesium and water, light to dark green, greasy-looking and slippery feeling. It can resist the transfer of heat. A source of asbestos, architectural stone, ornamental stone, gem material
- Minerals present: it follows the formula (X)2-3(Y)2O5(OH)4 where X can be magnesium, iron, nickel, aluminum, zinc, or manganese; and, Y will be silicon, aluminum, or iron.
Green Schist
- Formation: they form by regional metamorphism of mafic igneous rocks through depth of burial, and proximity to batholiths.
- Characteristics: The green is due to abundant green chlorite
- Minerals present: actinolite and epidote mainly, but they can also include quartz, orthoclase, talc, carbonate minerals, and amphibole.
Basalt Pillow
- Formation: it forms when lava of basaltic compositions erupted underwater. The rapid cooling of the lava forms the pillow-shaped bodies.
- Characteristics: they are volcanic igneous rocks, very dark, almost black color.
- Minerals present: Basalt has a lower percentage of silica and a higher percentage of iron and magnesium than other volcanic rocks.
Umber
- Formation: it develops in Cyprus massive sulfide deposits.
- Characteristics: is not one precise color, but a range of different colors, from medium to dark, from yellowish to reddish to grayish depending on the iron oxide and manganese in the clay
- Minerals present: contains iron oxide and manganese oxide and sulfide precipitates like pyrite.
I hope you find this information useful and interesting! Good luck!
