Hazard Roundup--February 2009

Welcome, and thanks for tuning in to the February 2009 edition of the USGS Hazards Roundup. My name is Brian Campbell, your host.

The natural hazards that occurred in February were largely concentrated in the first half of the month and the events that we will focus on in this edition of the Hazards Roundup were unique in many respects, particularly in regard to where they occurred, as well as their scope and intensity. An earthquake on the east coast of the U.S.? One month's worth of rainfall in 24 hours in Great Britain? The greatest loss of life to bushfires in Australia's history? Let's get into it...

Hundreds of earthquakes occur every month, several of them significant enough to warrant some degree of attention. While the size of an earthquake is often the factor that determines whether an earthquake event is picked up by national or international media, this is not always the case. The location of the quake can also play a role, particularly if the location is one where quakes are less common. This is precisely what happened on February 3 when an earthquake struck the east coast of the United States, in the greater New York-New Jersey area. Sure, it may have been a mere magnitude-3.0 quake. Sure, the magnitude-7.2 quake that struck northeastern Indonesia on February 11th may have had aftershocks that released almost 30,000x more energy than it. But it was still an earthquake on the east coast of the U.S.!

According to the USGS, smaller earthquakes in the New York-Philadelphia-Wilmington urban corridor are felt about every 2-3 years, while moderately damaging earthquakes occur about twice a century. And while earthquake events are far less common in the eastern U.S. than the western U.S., they can oftentimes be felt over a much broader region. Furthermore, while the fault systems in southern California, for example, are well-studied and understood, this is not the case in the eastern U.S., where it is difficult to determine if the few named faults are still active. Consequently, with such a limited understanding of the tectonics of the eastern U.S., an earthquake event such as the one that occurred on February 3 can prove difficult to study and analyze. Nonetheless, it was a fascinating occurrence and reminder that California is not the only state susceptible to earthquakes...

Let's shift topics to precipitation in Great Britain. Now you might be thinking to yourself, how could precipitation in Great Britain possibly warrant attention in a Hazards Roundup? Well, we are not talking about a common afternoon shower. Beginning on the first of the month and continuing through the second week in February, Great Britain and Ireland experienced widespread snow accumulation and rainfall. Over 10 inches of snow fell on parts of the English countryside, while 6 inches accumulated in London, an uncommon occurrence that prompted the city to remove all buses from the streets on February 2 and severely disrupted rail service as well. Heathrow and Dublin airports were also closed for periods of time. The snowstorm was followed by another winter storm that brought more snow, heavy rains, and gale-force winds. Over one hundred flood warnings were issued and thousands of homes lost power. To put the storm in perspective, on February 10, 24-hour rainfall totals in parts of southern England almost exceeded the monthly average. That is a lot of rain, even for Great Britain.

While Great Britain was being battered by rain and snow, the Australian state of Victoria was blazing with a series of deadly bushfires that claimed over 200 hundred lives. While suspicions of the causes of the fires were widespread, the fires were exacerbated by some of the worst bushfire-weather conditions in Australia's history. An on-going drought, temperatures in excess of 100 degrees F, and sustained winds greater than 60mph fueled the blazes. One particular fire, situated northeast of Melbourne, accounted for over 90% of the recorded fatalities. The blazes continued throughout the month, prompting officials in Australia to enter into a dialogue about reconsidering building plans and strategies to combat arsonists, as well as the potential contribution of human-induced climate change to the 50-year warming trend in Australia.

Well, that about wraps it up for this month's edition of the USGS Hazards Roundup. Until next time, I'm Brian Campbell, thanks for tuning in.

Hazards Roundup is a product of the U.S. Geological Survey, Department of the Interior.  

Resources related to this episode:

• USGS earthquake hazards information
• USGS flood hazards information
• USGS wildfire hazards information