The waterfall cave is very long, and it has been several hundred meters in the waterfall cave before the explorer enters a relatively spacious place. This is a small lime crack, the ground is a little wet, and a layer of very shallow water flowing slowly on the surface. With this amount of water, it will probably take half an hour to fill a mineral water bottle.

This is obviously groundwater seepage. If it rains outside, the water flow here will probably become larger. From the size of this gap, it can be estimated that the formation time here is not too long, and it is estimated that it will only be hundreds of years.

In the karst terrain area, the rivers on the ground reach the east to the sea, and there is another set of rivers underground reach the east to the sea. As the capping of a mountain, it is probably the origin of an underground river or the source of a tributary.

According to the guidance of the detection structure diagram, the explorer continued to penetrate deep into the ground along the direction of the water flow. While the explorer was exploring here, the sky-patrol eagle was circling over its head.

Now the flight altitude of the Sky Patrol Eagle has dropped, and it is circling over the hill. The detection radar aims at the explorer's position, constantly switching the bands, scanning over and over again. Under this high-precision detection, the geological structure around the explorer is extremely clearly displayed.

“Try ultrasonic scanning!”

Watching the explorer wandering in the underground lithotripsy, Meng Yang decided to test the relevant organs and see the effect first. Don’t wait until you find that it doesn’t work when you need it.

With Meng Yang's order, the explorer's head began to change, a raised bulge in the position of his nose, his ears began to expand and become larger, and a bat ear began to grow from the head of the original lizard.

squeak!

A sound wave that human ears cannot hear is emitted in a fan shape. Then these sound waves continue to rebound, refract, reflect, and echoes on the surrounding rocks. After various processing, the surrounding terrain is slowly outlined.

Compared with infrared visual images and detection results, the ultrasonic positioning accuracy is good. Unfortunately, its working range is a bit short and can only scan terrain within 50 meters. If it is far away, blur and error will occur. It is estimated that it is related to the terrain environment and distance loss.

"Structural detection under test."

squeak!

The fan-shaped sound waves were not launched forward this time, but were directly launched into the rock formations under the explorer's feet. The ultrasonic waves hit the rocks, and most of them reflected back, and a small part went directly into the rocks and continued to spread downwards.

Sound waves spread within the rock, and while propagating, various refractions occur continuously. A large number of echoes will be fed back to the surface. These echoes are collected by the ears, and the internal structure and density changes of the rock are clearly outlined.

The rock formation detection distance is only more than two meters, and valuable echoes are completely impossible to collect more than five meters.

"Open the infrasonic detector."

Ultrasound is very directed, but infrasonic waves are just the opposite. They are difficult to use as an active detection wave, but they are equally valuable.

A large number of infrasonic waves will be generated in the environment, and most of these infrasonic waves are relatively weak, but large-scale geological activities and climate activities will produce powerful infrasonic waves. These infrasonic waves have practical detection significance and can be used to early warning of geological disasters and climate change.

Close-range infrasonic wave detection can be used as a means of biological detection and is also of great value in disaster search and rescue.

The explorer's eardrum changed slightly, and the infrasonic wave reception mode was turned on.

The noisy infrasound waves around were immediately revealed, including the infrasound waves caused by the flow of air flow, the sound of mountain wind passing through the woods, the tremor caused by the heat, dirty, cold and uneven shrinkage of the mountains, the sound of water flow washing through the rock walls, and even the sound of biological internal organs moving...

These sounds are like background noise. After countless refractions and diffractions of the mountain, the source direction has been completely blurred. The only thing that can be done is to distinguish who made these sounds.

Although most sound waves cannot distinguish the source direction, some sound sources that are relatively close can still be distinguished. One of the sounds of water flowing is more than 40 meters below.

"Compare the detection map."

Retrieve the detection map. There is a river more than 40 meters below the explorer. The water volume of the river is not large, about two or three cubic meters per second, which is the level of a stream.

"keep going."

The underground river has nothing to do with this exploration goal. It passes through the explorer and will rush out of the surface again after walking a few kilometers, turning into a clear spring.

The explorers have penetrated nearly a hundred meters underground, and the temperature in the dissolution gap is constant at about five degrees above zero, the humidity is not high, and the carbon dioxide content is much smaller than the surface.

The carbon dioxide in the air is constantly absorbed by the surrounding water molecules, and then combined with the surrounding limestone to become soluble minerals. Once the water flows through, these solutes will be taken away and slowly erode the karst landforms unique to the limestone formation.

The lithocratic cracks quickly reached the end, and explorers appeared on the side wall of a cave. The cave was covered with bell stones of all sizes. Drops of water were dripping down on the top of the cave, and they gathered into an underground river at the bottom of the cave. The cave was not big, only a dozen meters wide, and the shallow part of the underground river was only half a meter deep.

“Switch to diving mode.”

The explorer lies on the wall of the cave and begins to deform. It first grows a pair of gills, the lizard's tail is transformed into a fish tail, and the twenty pairs of short legs change from eagle claws to duck's paws.

The conversion was soon completed, and the explorer climbed down the hole wall and drilled into the water. As soon as the ultrasonic and infrasonic detectors were turned on, they caught some strange signals. Through the outline of the ultrasonic waves, the shape of the sound source was quickly outlined. This is a fish about twenty centimeters long.

"Look closer and turn on the searchlight."

A searchlight rises on the explorer's head, which consists of enhanced firefly luminous cells, which combine into a small flashlight shape that can gather straight beams.

A beam of light appeared in this dark cave, which may be the first beam of light that appeared in this cave in hundreds of thousands of years.

The light illuminated the mirror image at the bottom of the water. A strange fish with almost transparent body appeared in the field of view. The fish was like an enlarged and elongated tadpole, with no color on its body, and its whole body was translucent, and its internal organs were clearly visible.

The strange fish had no response to the sudden light. It had no eyes on its head and only two unobvious black spots. This was obviously a degenerated eye.

Its mouth is very similar to the tadpole's mouth, and it seems to be two open and closed skin, neither tooth nor normal mouth contour, as if a small hole suddenly cracked on the head.

It seems that there are biological survival in this cave.

"Open the biodetector."

This is a bioelectric detector, and when it starts working, a starry sky of life appears around the explorer.
Chapter completed!