This is a detailed timeline for Xx_Diictodon_xX's Extinction Event.
Before Common Era
Somewhere off the coast of the modern day Yucatan Peninsula, a meteor almost the size of Mt. Everest hits. This results in a series of events that leads to the extinction of the dinosaurs.
The Russian astronomer G. N. Neujmin discovers an asteroid in the asteroid belt between Mars and Jupiter. He names it Gaspra after a Black Sea hide-out.
The Jupiter-orbiting spacecraft Galileo passes about 990 miles away from the asteroid Gaspra. It takes some images and records a lot of data and sends it back to Earth.
Earth receives the data and images from Galileo. Scientists from NASA proceed to analyze the images and data. They identify the asteroid as Gaspra, and most celebrate because it is the first asteroid encountered by a spacecraft probe.
NASA Scientist Gregory K. March, after running some diagnostics on the data discovered by Galileo, he works on the trajectory course that Gaspra will take over the next 20 years. After hours of work, he discovers that Gaspra will pass near Earth, close enough to be seen with little aid in 2005. He's quick to contact the President of NASA, Richard H. Truly, and tell him the news.
Before emptying the rest of what is stored in his inbox, Truly discovers an odd email implying an asteroid that would fly by Earth in 2005. He contacts the sender of the email, asking for more data on the asteroid.
March checks his email, finding the unexpected email from Truly. After finding out that the President of NASA wants more data, he immediately sets to work on scrubbing all the files he's made on the asteroid and once he believes he has all of the necessary data, he sends it to Truly.
Truly is able to find the response after days of searching through his crowded inbox. He takes the data he's gotten and sends it to the head of the Heliophysics Division director Steven W. Clarke, asking if the data that he's been given is correct. Clarke receives the data the same day and him and his colleges set to work on the data.
After about a month of testing, Clarke comes to a conclusion that the data he received is correct and sends the news back to Truly.
Once Truly receives the news, he and Alvin C. Gardyner found the Near-Earth Object Program (NEO) to monitor Gaspra and any other comets, meteors and asteroids that pass close to Earth.
Daniel Goldin is announced the new President of NASA.
Gaspra very closely passes another, undiscovered asteroid, throwing both paths off just barely, but enough so that Gaspra's path intersects with Earth. This goes unnoticed.
During a conference meeting, NEO and the Gaspra case is brought up and Goldin decides to make the division public.
NEO is made public, along with the Gaspra flyby.
Finnegan Hatheway, an astronomer in Alaska discovers that Gaspra could possibly hit Earth, but believing that they'd just dismiss it, he doesn't alert NASA or anybody else.
Michael D. Griffin is appointed as the new President of NASA.
Gardyner, the former Director of NEO, calculates the day that Gaspra will fly by Earth, April 11th.
Mason Plaskett, a scientist working at the HQ of NEO, discovers that Gaspra, instead of narrowly missing Earth, will instead hit it right on. He quickly contacts Griffin. Griffin gets the news and calls the White House. He tells the staff there the news, but unfortunately the President is in Colorado for a meeting, and only the Vice-President is at the White House. In a panic, Griffin sets up a team, including Plaskett, and informs them to find the exact spot Gaspra will make impact. They set to work, using all the information that they have been given to find the coordinates.
Working all through the night, the team finds where Gaspra will hit - somewhere off the coast of the Yucatan Peninsula. Griffin is notified, who then proceeds to inform the government. Although they find it unwise, they figure it is only appropriate that the public is notified, even if it is as late as it is. The President hops aboard Air Force One, and is flown to an airport in northern Canada where he should be safe from Gaspra. News stations across the world relay the information of Gaspra. Most people in and near the Yucatan Peninsula know that their time is up, but some refuse to believe that and try to get north. At 8:52 PM UTC, the meteor makes impact. Instantly, anybody and anything in a 200 mile radius of the impact is vaporized, and it can be felt all over the world. The blast continues to spread, and reaches as far north as Missouri, and as far south as Panama. In about an hour, mega-tsunamis over 3 miles tall reach southeastern United States, and Northern South America, and wipe out most of it. The Caribbean Islands and all islands around them are drowned by the tsunami, and Florida and other southeastern states are completely put under water.
The tsunamis soon reach Western Africa and Europe. The water enters the Mediterranean Sea through the Straight of Gibraltar, widening it to almost 30 miles across. Almost all of the islands in the sea are put under water, and Italy is drowned as well. The water proceeds into the Black Sea, widening the Dardanelles and Bosporus Straights by almost six times as much. As this is happening, the tsunamis surge around Africa and into the Indian Ocean, almost completely wiping out Madagascar. Sri Lanka, Indonesia, the Philippines, and all other small Pacific Islands are wiped out, and some of western Australia is wiped out as well. The water reaches Hawaii, although is about one-quarter of its original height, but it still is tall enough to surge forward and wipe out practically all of the Hawaiian Islands, leaving only a small amount of the Big Island left. Soon, the water reaches the western coast of the US, and wipes out some of the western states and provinces, although most of the Pacific Islands are drowned by the water.
From space, the coasts of the world, especially the Gulf of Mexico, are unrecognizable. On Earth, people begin to recover from the shock of what just happened. To the people of the Western US, it is a miracle that the San Andreas fault or the Yellowstone supervolcano didn't go off. Although, the people of the northwest aren't all that lucky. The Cascadia Subduction Zone, just west of the land, shifts, resulting in a 9.7 magnitude earthquake. This in turn also triggers its neighboring fault line, the San Andreas, creating an 8.4 earthquake. Each earthquake lasts for as much as ten minutes, but soon die down. The landscape of the Western United States and Southwestern Canada is practically unrecognizable. Those who remain scramble about, unsure of what to do. Although the President of the United States is safe, the Vice-President isn't. News is broke that the White House was drowned by the tsunami. Those left in Mexico proceed to cause chaos. Meanwhile, the tsunami caused by the earthquakes surges across the Pacific.
Some of the remaining people in Mexico decide that it is only best if they immigrate up to the United States. Groups of up to 500 travel north to the border. The tsunami reaches what remains of the uninhabited Hawaii, and surges over it, wiping it out for good. Some of the people of the Western US band together, establishing bases in what town centers and city halls remain. Around the world, leaders unite to help evaluate the damage and to help those in need. Those left in Japan attempt to get back to the mainland, but the tsunami reaches Japan, and catches all the people trying to get away.
The first terrorist attack since the asteroid strike occurs in Chandler, Arizona, a shooting near the city hall. This results in the government of Arizona to heighten marshal law and issue a curfew. The President leaves Canada on Air Force One and heads back to the United States. There, he and the rest of the crew go to a safe house somewhere in West Virginia.