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Volcano Watch — Of Animals and Earthquakes (My Cat Felt That)

October 23, 2008

When filling out felt earthquake reports, many people describe strange behavior by their pets just before an earthquake.

East Han Seismograph

For centuries, there have been accounts of abnormal animal behavior prior to earthquakes. There are several examples from Japanese literature of abnormal behavior of fish, birds, and small mammals. These include examples of abnormal fish migration and behavior reported by fisherman, such as deep-sea carp or mackerel appearing in large numbers in waters much shallower than their normal habitat, and examples of carp and catfish in ponds located in major cities that showed agitated behavior in the days or hours prior to an earthquake.

In the 1930s, Japanese researchers studied the behavior of catfish in fish tanks. The researchers did not find noticeable change in catfish behavior due to an impending earthquake alone; however, they did find that the catfish responded differently to a person tapping on the fish tank, depending on whether an earthquake was approaching. If an earthquake was about to happen, the catfish reacted very nervously to tapping on the tank, if not, then the catfish would barely stir when the tank was tapped.

Another example was reported by fishermen, who found that sardines, which usually eat plankton in the shallow layers of the sea, had eaten an unusually high amount of bottom-dwelling organisms the evening before a large earthquake. Suggested explanations are that the sea bottom had been disturbed by some earthquake precursory motion. Historically, some Japanese fisheries have also reported abundant catches preceding earthquake activity.

Humans have long held that a tight link exists between earthquakes and animals, which is embodied in the earliest known earthquake-detection instrument invented in A.D. 132 by Zhang Heng, a Chinese philosopher. The instrument was a large (2 meters, or 6.5 feet, in diameter) bronze jar, with a central pendulum inside. Decorating the outside of the jar was a series of dragon heads connected to a pendulum, each with a ball in a hinged mouth. Directly beneath each dragon head, on the surface of the stand, was a bronze toad, head up, mouth open to receive a ball from the dragon's mouth.

During an earthquake, the ground motion would move the pendulum and cause one or more balls to fall from a dragon's mouth into a toad's mouth. The direction of the earthquake was indicated by which of the dragon's heads had dropped a ball. Today's earthquake-recording instruments have finely tuned electronics, but the basic design remains similar to the earliest devices, with a pendulum or a weight on a spring at the core of the device, usually without toads or dragons.

The majority of anomalous animal behavior reports are anecdotal; however, given that they are widespread and persistent, there may be some physical basis to their occurrence. One potential explanation is that animals have developed a higher sensitivity to earthquake precursory signals through evolutionary processes. Animals living within seismically active regions are more susceptible to death from burrow collapse. Therefore, animals that have the ability to detect earthquake precursors (a seismic escape response gene) would be naturally selected over those animals that do not.

If animals are more sensitive to precursory earthquake signals, perhaps observations of animal behavior could be used as a predictive tool. However, interpretations of anomalous animal behavior are weighted heavily by human interpretation. Since we cannot communicate directly with animals, we cannot know if the observed anomalous behavior of a particular animal is caused by an upcoming earthquake or by some other outside factor.

In most cases, the abnormal behavior is only noted in hindsight, after the earthquake has occurred. There is no scientific control, such as a full record of the animal's behavior during time periods when there were no earthquakes. So, please don't tap on the glass, and if your cat is acting odd, you might just have an odd cat.


Volcano Activity Update

Kīlauea Volcano continues to be active. A vent in Halema`uma`u Crater is erupting elevated amounts of sulfur dioxide gas and very small amounts of ash. Resulting high concentrations of sulfur dioxide in downwind air have closed the south part of Kīlauea caldera and produced occasional air quality alerts in more distant areas, such as Pahala and communities adjacent to Hawai`i Volcanoes National Park, during kona wind periods. The have been several small ash-emission events from the vent, lasting only minutes, in the last week. Pu`u `Ō`ō continues to produce sulfur dioxide at even higher rates than the vent in Halema`uma`u Crater. Trade winds tend to pool these emissions along the West Hawai`i coast, while kona winds blow these emissions into communities to the north, such as Mountain View, Volcano, and Hilo.

Lava continues to erupt from the Thanksgiving Eve Breakout (TEB) vent and flows toward the ocean through a well-established lava tube. Lava breakouts in the Royal Gardens subdivision have been active throughout the past week, creating small fires in vegetation along the flow field margin. Activity at the Waikupanaha ocean entry has fluctuated over the past week. A deflation-inflation (DI) event at the summit led to a short pause in activity at the ocean entry on Monday, Oct 20. At other times during the past week, vigorous ocean entry activity and littoral explosions have been observed.

Be aware that active lava deltas can collapse at any time, potentially generating large explosions. This may be especially true during times of rapidly changing lava supply conditions. Do not venture onto the lava deltas. Even the intervening beaches are susceptible to large waves generated during delta collapse; avoid these beaches. In addition, steam plumes rising from ocean entries are highly acidic and laced with glass particles. Check Civil Defense Web site or call 961-8093 for viewing hours.

Mauna Loa is not erupting. Three earthquakes were located beneath the summit this past week. Continuing extension between locations spanning the summit indicates slow inflation of the volcano.

One earthquake beneath Hawai`i Island was reported felt within the past week. A magnitude-2.5 earthquake occurred at 4:35 a.m., H.s.t., on Wednesday, October 22, 2008, and was located 8 km (5 miles) west of Waimea at a depth of 34 km (21 miles).

Visit our Web site for daily Kīlauea eruption updates, a summary of volcanic events over the past year, and nearly real-time Hawai`i earthquake information. Kīlauea daily update summaries are also available by phone at (808) 967-8862. Questions can be emailed to skip past bottom navigational bar