Backstory Help: Asteroid Collision in California

[Author_X]

I am currently working on the backstory to a story I'm writing as a means of world-building. However, I'm not quite as physics-literate as everyone else, so rather than winging it and coming off like an idiot, I came here.

http://sta.sh/0126svntmin
Exhibit A. The red marks the range of the crater, the black dot is ground zero.

Southern California was destroyed several decades before the story proper. The cataclysmic Salton Sea Event wiped out various cities, reaching into Nevada and Arizona. The Baja California peninsula was also separated from the land, becoming an island through the formation of the Gulf of California.

The official report claims an asteroid did this.
What size, speed, and amount of force would be enough to generate a crater that large?
What sort of effects would the blast have on the region? I can be certain about wildfires and Las Vegas would be affected by the aftershock.

 

[Bandersnatch]

http://sta.sh/0126svntmin
Exhibit A. The red marks the range of the crater, the black dot is ground zero.

What size, speed, and amount of force would be enough to generate a crater that large?
What sort of effects would the blast have on the region? I can be certain about wildfires and Las Vegas would be affected by the aftershock.

This crater is larger than the Chicxulub crater - you'd have a global extinction event more severe than the one that killed the dinosaurs.

 

[Author_X]

This crater is larger than the Chicxulub crater - you'd have a global extinction event more severe than the one that killed the dinosaurs.

How big would an event have to be to render southern California uninhabitable, but still allow life (including humanity) to continue?

 

[Bandersnatch]

Use this handy calculator:
https://www.purdue.edu/impactearth/
Play with the variables until you get what you need.

 

[Noisy Rhysling]

This crater is larger than the Chicxulub crater - you'd have a global extinction event more severe than the one that killed the dinosaurs.

Some people just want to watch the world burn.

 

[Vanadium 50]

How big would an event have to be to render southern California uninhabitable, but still allow life (including humanity) to continue?

Well, many of us feel that Southern California is unfit to live in even today.

I don't think what you want is possible. You can make an area uninhabitED but not uninhabitABLE. Once the fires have gone out, nothing really prevents life from moving back in.

 

[mfb]

I don't think what you want is possible. You can make an area uninhabitED but not uninhabitABLE. Once the fires have gone out, nothing really prevents life from moving back in.

A large crater filled with sea water should work. But that would have global consequences.

 

[Noisy Rhysling]

How about having the meteor trigger The Big One? Then you could rearrange the landscape creatively without wiping out life in Maine.

 

[Noisy Rhysling]

Also, read Footfall, by Larry Niven and Jerry Pournelle. Be ready to defend your work in regard to this book.

 

[Ryan_m_b]

Well, many of us feel that Southern California is unfit to live in even today.

I don't think what you want is possible. You can make an area uninhabitED but not uninhabitABLE. Once the fires have gone out, nothing really prevents life from moving back in.

True but in terms of human resettlement there are political and economical factors at play. California is a big place but if an asteroid, bomb or whatever wiped out some of the major cities the US (and by extention the world) economy would nose dive. California is so rich that were it its own nation (ignoring the economic consequence of leaving the USA) it would be the 5th or 6th richest country in the world.

OP I'd advise you look down this route. If you look up richest cities in California and play with the impact calculator posted by Bandersnatch you might find that you could hit enough to wipe out trillions of dollars of GDP.

Such a massive shrinkage of the US economy, not to mention the expense of rehousing the survivors, could push back resettlement by decades or even longer. You say "official story" as though there's a conspiracy in your novel, if so this works in tidily. The "party line" could be that California will be rebuilt once the economy recovered (which could take quite a while). Meanwhile politicians kick that promise down the curb and only the die hard Californians (numbering less and less as the refugees integrate into other states) and economic idealists rave about how the US could rebuilt if it wanted too.

 

[snorkack]

36 years after Mt. St. Helens exploded, how many people live in the area where the people present in 1980 died?
No infrastructure. Coarse soils of rubble. Poor vegetation.

Compare Barringer Crater. Estimated at 10 MT.
The crest of the crater rim is about 600 m radius. But the present height of the crater rim is 45 m above the surrounding plains - and before erosion, say a few hours after explosion, the height of the rim is estimated to have been about 15...20 m higher, so about 60...65 m above the previous ground.
How far from the epicentre was the level 6 m above previous surface? 60 cm above previous surface?
How far from Barringer Crater epicentre would a man have died?

 

[Noisy Rhysling]

36 years after Mt. St. Helens exploded, how many people live in the area where the people present in 1980 died?
No infrastructure. Coarse soils of rubble. Poor vegetation.

http://www.cbsnews.com/news/35-years-after-mt-st-helens-eruption-nature-returns/

Compare Barringer Crater. Estimated at 10 MT.
The crest of the crater rim is about 600 m radius. But the present height of the crater rim is 45 m above the surrounding plains - and before erosion, say a few hours after explosion, the height of the rim is estimated to have been about 15...20 m higher, so about 60...65 m above the previous ground.
How far from the epicentre was the level 6 m above previous surface? 60 cm above previous surface?
How far from Barringer Crater epicentre would a man have died?

http://www.lpi.usra.edu/science/kri...enviropages/Barringer/barringerstartpage.html