Japanese Earthquakes continue...

The scene of destruction in Japan due to the large magnitude 9 earthquake and resulting tsunami has shocked and saddened us all - especially since I spent some time in Sendai and the surrounding area in 1999. And the photographs of the aftermath are heart breaking.

What has also astonished me are the huge numbers of aftershocks in the area.

Using data from the US Geological Survey, I have plotted a graph of the seismic activity around Japan over the past week (see below). The strength and number of aftershock is astounding.

Remember, a magnitude 4-4.9 earthquake causes noticeable rattling, and for every unit you go up the scale, an earthquake is 10 times stronger. A magnitude 5 quake, being ten times more powerful than a magnitude 4, can already do damage. The magnitude 9 quake that Japan experienced last week is 10,000 times stronger than a magnitude 5 quake - almost incomprehensible.

The graph shows...

• 1 Mag 9 Earthquake
• 1 at Mag. 7.1
• 37 between Mag. 6.0-6.8
• 258 between Mag. 5.0-5.9

That's 300 earth-quakes, all of which could cause structural damage, in just one week. Terrifying.

One wonders when will these earth-quakes end?

Space Station and Shuttle following each other

As I write this, the Space Shuttle Discovery and the International Space Station have just closed the door between each other, as the Shuttle crew prepare to return to Earth. The two vehicles will separate at noon GMT tomorrow (7th March, 2011), and so on the evening of Monday the 7th March we will get the rare (and last?) opportunity to see the two spacecraft following each other in the night sky over the UK.

We will have two attempts to see them fly over the UK together on Monday...

The first past will be very difficult to spot, since the Sun is not setting until 17:50 - but you may just get a glimpse of the pair as they disappear in the East (it is sometimes possible to see the space station in daylight!)

• Rising just North of West at 17:46 GMT
• Reaching 72° high in the South at 17:50
• Setting at 17:53 in the East

The pair fly over the UK again 96 minutes later, but by then they only get 19 degrees above the horizon...

• Rising in the West at 19:23 GMT
• Reaching 19° high in the South-West at 19:25
• Setting at 19:27 in the South

You will get another chance to see the Shuttle and Station on Tuesday 8th March, as they fly over the UK from 18:13 GMT in the west, peaking at 18:16 GMT in the South some 36° high, and disappearing at 18:19 GMT - but who knows how far apart the Shuttle and Station will be by then?

For more details, including live footage from NASA TV, see SpaceFlightNow.com.