forecasters.The epicenter of the quake, which struck at 6:45 pm (0045 GMT), was located 145 kilometers (90 miles) west of the capital San Jose, but only five kilometers from the town of Hojancha, the US Geological Survey said.
People throughout the world are concern if earthquakes are on the increase. Although it may seem that we are having more earthquakes, earthquakes of magnitude 7.0 or greater have remained fairly constant.
The Costa Rica earthquake is below that magnitude, nevertheless there is still no real evidence of quake increases.
A partial explanation may lie in the fact that in the last twenty years, we have definitely had an increase in the number of earthquakes we have been able to locate each year. This is because of the tremendous increase in the number of seismograph stations in the world and the many improvements in global communications. In 1931, there were about 350 stations operating in the world; today, there are more than 8,000 stations and the data now comes in rapidly from these stations by electronic mail, internet and satellite. This increase in the number of stations and the more timely receipt of data has allowed us and other seismological centers to locate earthquakes more rapidly and to locate many small earthquakes which were undetected in earlier years. The NEIC now locates about 20,000 earthquakes each year or approximately 50 per day. Also, because of the improvements in communications and the increased interest in the environment and natural disasters, the public now learns about more earthquakes.
I have tended to believe what many scientists say that we are looking at the issue from too narrow a time scale. The commonly held theory is that the earth goes through periods of activity and inactivity. With the earths poles potentially gearing up for a swap we might be in a period of higher activity for a while, and the recent Costa Rica quake perhaps represents such increased earthquake activity.
Contributor D. Chandler