Fourth earthquake rattles Italy: Are more dangerous tremors on the way? 第四次地震襲擊義大利：還有更多危險會發生嗎？

(CNN)Italy was struck by its fourth earthquake in three months on Sunday morning, a 6.6-magnitude tremor which injured twenty people and leveled a historic basilica.

義大利星期天早晨受到三個月內第四個地震侵襲，一個震度6.6級的地震，造成20人受傷，並將歷史深遠的大教堂夷為平地。

The deadly series of tremors has destroyed many historic buildings and landmarks. The first, in August, killed nearly 300 people and flattened villages around the mountain town of Amatrice.

這一連串致命的地震摧毀了許多歷史建築及地標，在八月的第一個地震造成將近300人死亡，並夷平了阿馬特里切山區城鎮附近的村落。

Sunday's was the strongest to hit the country in more than three decades.

Why has this part of Italy been struck so many times by disastrous quakes?

星期天的地震是三十年來襲擊義大利最強的地震，為什麼義大利這個區域被震災襲擊這麼多次？

Is this country witnessing a steady increasing in tectonic activity?

Here is what seismologists had to say.

這個國家正在見證一個逐漸穩定的板塊運動？以下是地震學家們必須說的。

Why has Central Italy had so many earthquakes?

為什麼義大利中部有這麼多地震？

Central Italy has a long history of severe earthquakes, along what is known as the Apennine "red belt".

義大利中央有一長串的地震史，有亞平寧山脈的「紅色皮帶」之稱。

Some of these quakes have been devastating, including one in 1915 which killed an estimated 32,000 people.

其中有些地震具有破壞性，包括1915的一場地震，造成估計3,200人傷亡。

"These (recent) earthquakes are related to one another, so part of an ongoing sequence in a region that has a high seismic hazard," United States Geological Survey (USGS) seismologist Gavin Hayes told CNN.

「最近這些地震的發生是彼此有關聯的，因此在發生過地震的地區內還有持續中的地震序列的話就會有高度震災的危險。」美國地理調查機構的地震學家Gavin Hayes告訴CNN。

According to the USGS, Central Italy has a number of fault lines running directly underneath it, which heightens the risk of earthquakes.

根據USGS，有很多斷層線在義大利中部的正下方，提高了地震的風險。

"No one can predict them but people just need to be aware that this behavior of the earth is quite normal, to have this kind of unpredictability," said Steve Tatham, a seismologist at Geoscience Australia.

「沒有人可以預測這些地震，但人們只是需要知道這些地震情況的無法預測很正常」澳大利亞地球科學局的地震學家Steve Tatham表示。

Will there be more? 還有更多地震嗎？

It isn't over yet -- aftershocks were still continuing in the region early on Monday morning.

還沒結束—星期一清晨餘震在該區域還仍然持續著。

"Following the earthquake there have been hundreds and we've already had 40 today ... I would imagine they would continue," Tatham said.

「緊接而來的地震有數百個，我們今天已經有40個了，我可以想像他們持續發生著」Tatham表示。

Hayes at the USGS said the initial quake in August was the start of the current spate of tremors and there could be more to come.

USGS的Ｈayes表示八月的第一個地震只是現在這些氾濫地震的開始，還有更多會發生。

"It's very possible that there will be more, there will certainly be ongoing aftershocks over the comings weeks to possibly months," he said.

「非常有可能會發生更多，而且在接下來幾週內到可能幾個月內也一定會有持續的餘震。」他表示。

Is central Italy becoming more prone to quakes?中部義大利變得更容易發生地震？

After four quakes in the same region in under three months, including the most powerful tremor in at least 30 years, residents might be asking if central Italy is now experiencing earthquakes more often.

在同一個區域在三個月內發生四次地震後，包括至少三十年來強度最大的地震，居民們可能會問現在義大利中部是否會更常有地震。

But seismologist Hayes said earthquakes only occur as long as there is fuel to power them -- that is, the energy which accumulates along faultlines.

但地震學家Hayes表示只有有燃料點燃他們，他們就會發生，而那就是累積在斷層線上的能源。

"These earthquakes don't represent any overall increase in tectonic activity, they're just clustered together because that's how earthquakes work," he said.

「這些地震並不代表整體的板塊運動增加，他們只是剛好聚集在一起，因為這就是地震形成的原因」他表示。

"Just think of it as an energy budget building up slowly over time and then being released fairly rapidly. Then the clock resets and then after a period of time another series of earthquakes will happen to release that energy."

「簡單把它想成能量平衡隨著時間慢慢堆積，然後相當快速地被釋放出來，然後這個時鐘又重新開始，過了一段時間，另一連串的地震會釋放出那些能源。」

While it is possible to forecast over what period an earthquake is more likely, based on knowledge of tectonic building rates and the time since the last major tremor, earthquake prediction in general is effectively impossible, Hayes added.

根據地震形成速率的知識和前一次發生的主要震動，雖然有可能預測什麼期間比較有可能出現地震，但整體來說有效的預測地震是不可能的。