Simcity Epic Projects

Land value and happiness are separate concepts.

• Land value aka desirability encourage wealthier sims to move in.
• Happiness encourages density increases.

Residential happiness comes from shopping! Turn on the commercial dataview and make sure that shoppers can go from residential zones to commercial zones with available goods. (Goods resupply automatically at 6 am and 6 pm. Goods have nothing to do with freight).

Residentials without money or without nearby goods will instead go to parks to get happiness. This happiness is just as effective at growing density as shopping (ie. your buildings will grow). However, there are some downsides. Parks cost you money, while commercial buildings pay tax. Parks take up more space to get the equivalent capacity of commercial buildings. Parks also increase land value - so you may accidentally bring in wealthier Sims than you really want (wealthy buildings hold fewer people).

If you need more jobs, you might need denser industrial zones. Industrial happiness comes from making shipments of freight. Turn on the industrial view. If there is a large pile of shipments at any building, that industrial is in trouble. Make more commercial zones or trade buildings to receive those shipments. Once received, those shipments will automatically vanish at some point allowing more to be received.

The achievments which unlock disasters seem to point to particular city conditions that may make a disaster more likely. For example, here are the achievements that are earned which unlock the player ability to trigger a disaster.

• Dug Too Greedily and Too Deep - Mine 100 tons of coal or raw ore in your city to gain access to the Earthquake disaster
• What Goes Up Must Come Down - Have 200 tourists arrive on flights at the Municipal Airport in a day to gain access to the Meteor Strike disaster
• Laboratory Outbreak - Add a Diagnostic Lab to a Hospital and have 15 Sims die in a day to gain access to the Zombie Attack disaster
• What's Cookin'? - Burn 100 tons of garbage in an Incinerator at the Garbage Dump to gain access to the Big Lizard disaster
• We Are Not Alone - Ship any resource to a Space Center Great Work to gain access to the UFO Encounter disaster
• Blowin' in the Wind - Have 24 Wind Turbines at Wind Power Plants in your city to gain access to the Tornado disaster

However, I can say from personal experience that I have had every one one of these disasters happen without any of the potential conditions listed by the achievement in play. I've had an earthquake with no mine, a meteor strike with no airport, a zombie attack with no Lab, etc.

This leads me to believe that disasters are truly random, and that you may just be luckier than your friends.

Without an official post from EA/Maxis we will never truly know. As I said earlier, I have experienced disasters of all types in small or large cities, dirty or clean cities, cities of different specializations, without a discernible pattern.