超级喷发

仅有的全球范围的剧烈变动，不过是由大的陨石撞击或超级火山喷发所引起。

The only abrupt worldwide change would have been major asteroid impacts or volcanic super-eruptions .

古代东加尼福利亚这场超级火山喷发形成了长谷火山口--约20英里长，11英里宽。

The ancient super-eruption in eastern California formed the Long Valley Caldera - a feature that is nearly 20 miles long and 11 miles wide .

通过对加利福尼亚主教凝灰岩（76万年前此地曾发生过一场超级火山喷发）浮石中的石英晶体进行显微分析，研究者们确定了这一结论。

Researchers have determined this based on a microscopic analysis of quartz crystals in pumice from the Bishop Tuff in California , the site of a super-eruption 760000 years ago .

如果超级火山喷发即将发生，那么该爆炸将喷射出足够多的火山灰到大气之中，从而扰乱接下来多年的天气，有可能会造成饥荒、健康危机和全球动乱。

If a super-eruption were to occur , the blast would launch enough ash into the atmosphere to disrupt weather for years to follow , potentially causing famine , health crisis , and global civil unrest .