Science 7 Quarter 4 Week 3 | Seismic Waves and Tsunami | MATATAG Curriculum

0:01 Okay. So hello grade 7 week 3. Okay. So this is still or continuation of our discussion about earthquake. Ano? So we will still continue the discussion about earthquake. So in week number one we just um conduct an introduction about earthquake. Okay. The types of fault. Okay, active and inactive. And then we somehow dipen it to the different types of fault which is the uh normal, reverse and the strike sleep fault. Ano? And then week number two naman uh we somehow okay discuss the anatomy of an earthquake. Okay? Starting from the focus, the epicenter, the fault. Uh what about this one? The sismic waves. Okay. So those are the terms that you have to

0:48 uh remember just the basics enough. Okay. So this time or this week we will discuss um what you call this the different types of sismic waves or then the occurrence of tsunamis. Okay. So those are the topics that we will explore in this topic ano earthquake scenarios and tsunami. Okay. So are you ready? So let's read the learning competency. So explain how earthquakes result in tsunamis that devastate sheline communities. Okay. So I know that you are already familiar mga anak sa tsunami ano kasi napapanood naman natin ito. And then like what I've said if you want to explore more about this you can watch movies like uh 2012 movie

1:36 na na-feature doon yung paggalaw ng San Andreas Fult. Okay? Napakaganda siya. Okay. Pwede natin siya sanang ipa-move marathon ano dito. But anyway, hindi na naman tayo aabot kasi still napaka okay napakakunti lang ng oras na alattin sa atin. So anyway, for our learning objectives this time, identify the different types of seismic waves. Okay. So we will discuss it thoroughly, okay? The types of sismic waves that travels within and within the earth surface, ano? And then explain how earthquakes result in tsunamis. Okay? Paano ba nagre-result? Okay. Yung earthquakes or paano nakaka-produce ng tsunamis? Okay? And then realize how tsunamis devastate shorline communities. Okay? So of course

2:23 if uh an earthquake happens syempre vulnerable. Okay. Or may there is a chance na possible 'yung mga nasa coastline regions. 'Ag sinabi nating coastline manganak or shoreline 'yung mga nasa dalampasikan medyo alanganin kasi 'di ba pag sinabi nating nagkaroon ng earthquake there are tendency that a tsunami or a tsunami will occure. Okay? So sige palawakin pa natin ngayon. So excited na ba kayo to learn something? Grade 7? Sige. So let's have a picture analysis. So this is a sort of review on the things that we discuss uh in week number two. Okay? So analyze the picture presented and think of one word that comes to mind after answering the following guide questions. Okay? Sige.

3:10 So what can you say? Okay what can you say on the picture? Na-flash ko na ano? Okay so sige. What can you say on the picture? Okay kunyari hindi niyo pa nakita yung word. Okay. [tawanan] Anyway, so kunyari hindi niyo pa nakita yung word. So the first thing that comes to our mind okay when uh we see this picture is the word earthquake right? Okay so yun yung una talaga nating maiisip because of the shaking of the ground, the shaking of the structures. Okay? So yun talaga iyung possible nating maisip in this scenario, ano? So what can you say about the word earthquake? Ano? Okay. What causes earthquake? Okay. Ano ba yung

3:56 nagco-cause ng earthquake mga alak? Again, sa week number one, paano natin ah masasabi na may earthquake na? Okay? Or paano ba nagkakaroon ng earthquake? It's because of the movement of what? Okay. So, nagkaroon ng movement saan? Sa fault line or dun sa crack sa fracture na tinatawag natin. Ang daming term eh. So fault can uh term ninyo mga anak lagi a crack a fracture. Okay 'ag gumalaw 'yung crack or 'yung fracture na 'yun there are tendency that an earthquake will be produced. Okay? May riple or may wave na map-produce or sismic waves na mapperuce okay within okay the earth surface or beneath the earth surface. Okay? So ayan earthquakes are caused by sudden movement of tectonic place along

4:43 falls. Okay? Yung paggalaw and there are several types of movement. Okay ' ba when the hanging wall moves downward, when the hanging hanging wall moves upward or the two blocks of rocks slide past each other. Okay? So those are the types of movement that we discuss in week number one. So hopefully masasagot or natatandaan pa din natin ano yun. Okay? So pag tinanong tayo what causes earthquakes. Okay? Earthquake is caused by sudden movement of tectonic plates or the fault. Okay. Or the crack. Yan. So, how does the magnitude of an earthquake affect the damage or the damage that it causes in the community? Again, mga anak, ano again yung tinatawag natin or what is the word magnitude?

5:28 Okay, in your own words, what is magnitude? Correct. Okay. Pag sinabi nating magnitude is the measure of energy. Okay? It um stands for the strength of the earthquake. The energy or the amount of energy released in the focus. 'Yun yung tinatawag nating magnitude, okay? Which we uh discuss in week number two. Okay? So we can um what do you call this? Ah meron silang level ' ba? May mga level yung magnitude. Magnitude ah 1 2 3 4 5 6 7 8 9. Okay? And then um the higher level. Okay. So pag halimbawa naman parang wala pa namang magnitude 10 kasi pag magnitude 10 na ay

6:13 ano yun catastrophic or talagang ano yun paggow na ano super lakas na non. So mostly okay yung ating ngayong nai-encounter in the modern day we can encounter magnitude 7, magnitude 8. Okay. But the most okay or inaabangan natin dito sa Philippines is yung movement. Okay? Movement ng West and East Valley na pag gumalaw yun okay or tinatawag nating the big one. Pag gumalaw yun okay there are yung approximately casualties is about 30,000 to 50,000 ano. Okay ang dami non. So sige. Sabi naan, higher magnitude earthquakes cause more severe damage. So pagtaas ng magnitude, as we observe, pagtaas ng magnitude, pag um dummy okay

7:00 or pagsever ng damages. Pero sinabi ko naman sa inyo, na in-explain ko din sa inyo that um though malakas malakas yung magnitude ng isang earthquake, naaapektuhan din ito doon sa level or lalim kung saan na-produce yung earthquake. For example, kung matatandaan natin yung nangyaring earthquake sa Japan and Myanmar, malakas yung earthquake na yon pero um konti lang ng yung naging damage. Though madami din. Sige sabihin na madami pero hindi pa hindi kasi ganun. Yung lakas kasi niya is hindi naging akma dun sa naging damage kasi bakit yung nangyaring din doun sa Thailand is napakalalim yung focus nasa pakailalim ng lupa. So yung pag-travel pa ng ah waves papataas malayo pero pag shallower mababaw yung

7:47 um focus yung source ng earthquake mas malaki yung damage na pwede niyang idulot. Okay. So yun ang tinitingnan din ng mga um what do you call this? Smologist. Okay. Kung gaano kalalim yung source nung earthquake. Okay. So next, what happens if the earthquake is generated underwater? What if yung earthquake naman ay na-produced? Okay. Underwater. Ito talaga yung tendency na mapwedeng magkaroon talaga ng tsunami just like what happened in Japan. Okay. So, nagkaroon ng tsunami sa Japan kasi yung nakapag-produce doon is underwater earthquake. Okay. So, ayan, underwater earthquakes can generate tsunamis. Okay, napaka-clear na yan. Sige. So, how

8:34 tsunamis are generated? So, this is our first activity. So, after watching the video, students will understand how tsunamis are formed and be able to answer the guide questions accurately. So meron kayong papanooring video nandon sa description 'yung link ng video. So pwede nating panoorin mga anak. So sige para naman doun sa mga nag-avail ng Php40 na PowerPoint nandun na din po sa drive yung video. You can download it and then pwede niyong ipa-play. Okay? Sige. So ito po yung link para doun sa mga hindi po naka-avail. Okay? So the teacher will play a short video clip to understand how tsunamis are generated and how they affect the sheline community. Okay. So sige. So let's say napanood niyo na 'yung video. So question number one, what is your reaction about the video? Okay. So it's

9:20 about ano lang naman, okay? Kung paano nage-generate 'yung tsunami. Okay? So the video is scary and informative. Okay, scary one is lahat naman ng mga disaster or yung mga video na about disaster is talagang scary ano so based on the video how are tsunamis generated? So tsunamis are generated by underwater earthquakes. Mostly talaga ng mga tsunami na po-produce because of underwater earthquakes. But sir, okay, pwede po kayong makapag-produce yung mga earthquake na nagje-generate sa lupa? Pwede if medyo malapit yung distance na niya sa dagat. Okay? Or malakas talaga 'yung magnitude. Okay? Ano? So sige. What are the possible damages brought by a tsunami? Ano 'yung mga possible

10:05 damages 'ag nagka-Tsunami? Okay. So tsunamis can cause flooding, pwedeng buhain, destruction and loss of life. Ito yung pinakamalala yung mawalan or may mga mamatay. Okay. So though this disaster or this phenomena or event is initable or hindi talaga natin pwedeng pigilan, it's unpredictable kung hindi natin napi-predict kung kailan mangyari yung earthquake. So all we have to do is to pray and be prepared always. That's why in school and even in different agencies or government agencies, we conduct a yearly or um what do you call this? Frequent okay, earthquake drills. Okay. So pag nagco-conduct tayong mga anak ng mga earthquake drills, you have

10:50 to be serious and you have to really practice kung paano talaga yung tamang pag-duck, cover hover and hold para naman pag nag ah-experience ninyo or nandun talaga kayo sa situation na yon is ma naa-apply ninyo yun. Kasi yung ginagawa nating earthquake is malaki ang pwede nating malaki ang pwedeng maging maitulong sa atin okay during this kind of uh disaster ano so sige unlocking case science vocabulary students will understand and correctly use important science terms related to wave motion and natural hazards. Okay? So mag-unlock muna tayo ng mga terms. Okay? So instructions decode and mystery word. The learners will decode the mystery word by altering the numerical

11:37 value with the vowels assigned to them. So yung A is 1,ung E is 2, yung I is 3, yung O is 4 at yung U is 5. So a E E O. Okay. So papalitan lang natin yung mga yung mga numbers ng vowels, ano. So the first word is correct. It's tsunami ano. So tsunami. Ayan. So next decode Mr. Word. Okay, it's okay. Body waves. Correct. What about this one? Okay. Ang gagaling. Surface waves. What about this one? Okay. Run up. What about this one? Okay. In uh ination.

12:23 Okay. So those are the words that we unlock this time. So we have ano yung mga na-unlock? Tsunami. Okay. We have Okay. Okay. So ano nga ulit yung mga words na na-discuss or naencounter natin? We have tsunami ano. So body waves. We also have surface waves. Ano pa? Run out and then and enadation. Ano? So yun ang ating mga words na nandon kanina sa vocabulary. So hopefully matatandaan natin ano. Next activity, identifying types of sismic waves. Students will identify the different types of body waves and surface waves based on their definitions. Okay. So sige, let's

13:09 continue. So types of sismic waves. Okay. So what have you learned about the anatomy of an earthquake? Ano nga ulit iyung natutunan ninyo about the anatomy of an earthquake? Okay. So ano nga ulit iyung crack with this one? Okay. It's the fault. Ano? What about yung parang reple motion? Okay. That's the sismic waves. What about this one? This point sa ilalim that's the focus. What about the point above the focus? That's the epicent or ano. Okay. So hopefully ah natan pa din natin okay yung ating mga parts or yung anatomy ng earthquake. Ayan. So next activity identify okay the correct systemsmic way. For the instructions,

13:56 learners will try to match the description with the correct figure. Okay? So meron tayong figure dito sa ating left side. Okay. So tingnan natin kung ano yun. Okay. Ano kaya yan? Ano yung perfect or type of sismic waves is being shown in the figure? Sige nga. Compression and expansion. Okay, for this one, it's a P waves. Okay, so P waves are compressional waves that travel through solids, liquids, and gases. Okay? They propagate through a substance by compressing and expanding. Tatandaan natin by compressing and expanding, okay? Alternately, okay? So pag sinabi nating propagate, parang pagkalat niya, how it is transmitted

14:42 from one media to another, okay? Or to another molecules or particles nagpo-propagate. Halimbawa galing siya sa ilalim, paano siya nag-propagate pataas? Okay. So sige. So iyung ating mga iyung waves na P waves they can travel through solids, liquids, and gases. Tatandaan natin compression and expansion. What about this one? Okay, it's okay, S waves. Okay, so iyung S waves naman natin are secondary waves. They are also known as sheer waves. Okay? And can only propagate in hard solid materials by vibrating particles in direction. Okay of the propagation. Okay. So nandun

15:29 po okay yung ating S waves or secondary waves. It can only travel okay through solid or hard materials. Okay na ano po ang kanyang ginagawa? Shearing forces. Shearing forces ano? Okay. So next what about this one? Okay. It's a railing wave. Okay. So rail wave. The motion of is a mix of longitudinal compressional and dilation. As a result the particles traveltically in the vertical plane. Vertically ano? Okay. Compressional and delayation. Okay. Diletation. Okay. So sige what about this one? Okay. Syempre that's the

16:16 love wave. So love wave particles forms a horizontal line that is perpendicular to the propagation direction. The energy of love waves radiates in two directions rather than three. Okay? So sige. So hopefully matandaan natin ano. Soiscuss natin one by one ano types of sismic waves. Okay? So yung ating nakikitang figures that's the earth crass ano? So the earth's grass okay yung part or layer one the outermost layer of our planet the crast. Okay. So yung crust natin yung pinaka-outer no pinakaibabaw na layer ng Earth. And of course dito tayo nakatira. Okay? Think of it this or think of it like this. Yung earth like an apple. Yung crust yung balat ng apple. And then sa crust makikita yung

17:02 mga tao, mga bundok, dagat, lupa, and then etcera. Ano? So meron tayong two types of crest mga anak. Yung continental and then yung oceanic. Syempre pag continental it is where we live. Okay. Continents. And then pag sinabi nating oceanic rest, 'yun naman yung nasa ilalim ng dagat, ano. Okay. So why is the picture about why is the picture about waves? Ano yung nakikita natin? Ano? So yung mga picture na yan nakikita natin is a type of sismic waves. Okay? So yan yung waves na nagmumula sa lindol. Hindi yung sa dagat iba yon. Okay yan yung waves na nagmumula sa lindon or energy ano so kapag gumalaw yung crest natin okay because the fault move okay nagkakaroon ng lindon at yung sa lindol yun ang napo-produce ay waves na kumakalat okay

17:50 sa loob at ibabaw ng earth para siyang nag-vibrate. Parang vibration pa kumakalat pwedeng sa loob ng Earth or paibabaw sa Earth. Okay? So meron tayong two main types of earthquake waves. 'Di ba 'yung body waves and surface waves. And yung ating body waves meron siyang dalawang type. The P wave and the S wave. Okay? Yung surface wave naman natin meron siyang two types ulit. Rail wave and the love wave. Okay? So unahin muna natin yung body waves. Ano? So yung body waves, mga anak, ito yung type ng wave na dumadaan lamang sa loob ng Earth's rest. sa loob ng earth. Ano yung loob ng earth? Nasa under ano beneath ano loob ng Earth. Okay. Una nito is yung P wave. Okay? Or the primary wave

18:37 or in other references pressure wave. So ito yung pinakamabilis. Okay? Pinakamabilis na wave. Gumagalaw na parang siksik siya na luwag. Okay? Parang hinihila at itinutulak. Nakakita na kayo nung slingki anak. Tinutulak at hinihila. Parang ganun yung galaw niya. Okay 'yun 'yung ating P wave. Napakabilis. Okay. And then 'yung S wave naman, ito naman ay mas mabagal. Pero sa loob din ng Earth, ano, sa loob ng Earth's Crest, mabagal compare sa P wave. Okay? Yung paggalaw naman nito is up and down. Up and down. Ano yung pagalaw? Up and down. Well, yung ating P wave, yung pagalaw niya is parang sinisiksik kino-compress. Okay? And then e-expand, compress,

19:22 e-expand ganun. Susiksik, luluwag gan compression and expansion while sa ating S wave up and down. Okay. Next. Nakakita na kayo ng lubid mga anak na parang ah ano pa yung ating lubid ay inaalog ganun parang nagwe-wave. Ganun yung ating sa S wave up and down movement. Okay. So, next we have surface waves. Ito naman 'yung type ng sismic waves na gumagalaw sa ibabaw ng crust, okay? Or within the earth's crust. At alam niyo ba na ang surface, kaya nga nandun 'yung na ah word na surface from the word itself surface, okay? Or within the earth surface yung pagalaw. Itong mga anak yyung pinaka-destructive kasi nakaabot siya sa surface. Ay alam na yung surface nandun yung mga building,

20:08 nandun yung mga tao nakatira. Okay. Kaya siya yung tinuturing na pinakaestructive. Okay. Sila yung nakakasilakas ng mga buildings. Unahin natin yung rail wave. Okay. Paano ba yung pagalaw ng rail wave? Yung galaw ng railay wave mga anak is parang ocean waves. Nakita kayo ng ocean waves? Yung alon literal na alon. Ganun yung paggalaw. Okay. Ng rail wave. Parang may rolling motion. Pero sa dagat, tubig naman 'yung nag-aalon-alon. Dito sa atin sa surface wave na relay, para siyang lupa na gumugulong. Okay? Kaya napakadelikado. Parang lupa na gumugulong 'yung paggalaw. Okay? And then we have love wave. Okay. So love

20:53 wave naman yung paggalaw niya is side to side. Okay? Parang ang lupa hinihila pakaliwa pakanan pakaliwa pakanan. Gann 'yung ating love. wave. Ito 'yung nakakasira ng mga roads and structures. Okay? Delikado to sa mga daan kaya nagkakabitakbitak yung mga roads ano. So hopefully medyo tayo ay nalinawan doun sa mga types of waves. So why are this waves important? Bakit naman importante to? Okay? Kasi nga sila yung a reason kay nakakaramdam tayo ng lindol. Okay na. And then sila din yung nagbibigay ng babala sa scientist. And then sila din yung mga tumutulong. Okay? Para mas maintindihan pa natin yung um nangyayari sa loob at labas ng ating planeta, ano.

21:40 Okay. So hopefully naman ay okay na tayo dito. Ano? So in depth discussion on types of sismic waves. Actually we already discuss ano. So sabi ko nga sa inyo, body waves travel through the interior of the earth and have a frequency higher than surface wave. Okay? Mas mabilis. Okay. Yung pay waves natin also known as the primary waves, pressure waves travel through both solid and liquid materials. So they move quickly. Mas mabilis to. and the first to reach the sismograph. Sila yung unang nade-detect ng sismograph. Ano po sir, yung sismograph? That's a device that we use to record uh the earthquake ano? So by compressing yung paggalaw dito ng P waves, compressing and expanding alternately, ano? Okay. So the particles velocity is parallel to the direction of the wave transmission. So 'yung S wave

22:27 naman natin, they are also known as the sheer waves and they can only propagate in hard solid materials, okay? By vibrating particles in a direction perpendicular to the propagation. Okay? So ano nga alat yung paggalaw ng S wave? Paano siya gumagalaw? May parang gulubid na inaalog-alog ano up and down. Okay? So next surface waves. Ito naman yyung waves that flow along the earth surface. Nakakaabot sa earth surface. air boundary or into the crass they have lower frequency than body waves. They are easily identified and are responsible for earthquake related damage and devastation. So yung mga dahilan ng mga nakakasira ng mga buildings, mga roads. Surface waves have particles that move in the circular leptical pattern and then the strength

23:13 of surface waves decreases as they go deeper below the surface. Okay? Una is yung rail ng ano rail waves. Pinangalan to. Okay. Sa British scientist na si Lord Riley. Okay. Who predicted their existence so their motion is a mix of longitudinal compressional andation as a result the particles travel elliptically in the vertical plate. Okay. This waves are dispersive and their amplitudes often decline exponentially with deep earth. So napakahaba nung paliwanag. Pero yung galaw lang naman niya is parang ah ocean waves kung nakita na kayo ano. So parang lupa na gumugulong like what I'm said earlier. Love waves naman named after British mathematician EA H love. Okay. According to him, the

23:59 particles of love waves jerk back and forth perpendicularly to the direction of wave transmission much like S waves. Parang side to side ano. So this motion of love wave particles forms a horizontal line that is perpendicular to the propagation direction. The energy of loves radiates in two directions rather than three. Okay? Side to side nga from left to right. The amplitude often diminishes significantly with depth. Okay? Lob waves move quicker than relay waves. Okay? So tandaan lang natin ano. So yun yung mga movement ng types of sismic wave. So sige nga, selfcheck muna tayo. True or false? Write true if the statement is correct. Otherwise, right? False. Body waves travel through the interior of the earth. Is it true or

24:44 false? Correct. through ano okay interior ano so surface waves have the higher frequency than body waves. Okay? It's false kasi mas mataas ang frequency ng body waves. Ano? Okay? Actually mas mabilis pa nga ang body waves. At ano nga yung ah unang nade-detect ng sismograph? Is it ah the P wave or S wave? Okay. Syempre iyung ating Okay, balikan natin. It's the Okay. Ayan oh, the e the P wave kasi siya yung pinakamabilis okay na wave. Okay? So mas mabagal ang S wave compared sa P wave. Okay? Yan tatandaan natin. Okay? So P waves can travel through both solids and liquids.

25:31 Is it true or false? Correct. It's true. And then P waves are the slowest sismic waves. Mhm. It's false kasi ito iyung fastest. as waves can travel through liquids and gases. Okay? It's false and also sa mga hard lang ito nagta-travel. Okay next. S waves move particles perpendicular to the direction of the wave travel. Okay, it's true. Okay, surface waves cause most earthquake damage. Syempre it's true pa din ano railing waves particles in the circular or elliptical motion. Syempre it's true pa din. Parang gumugulong circular eh. Love waves particles na vertical motion. Okay. It's fall side to side po yung ano niya left to right. Love waves um horizontal kasi

26:18 siya side to side eh. Okay. Love waves travel slower than rail waves. Okay? It's false ano. Okay. So next. Surface waves lose strength as they move deeper into the earth. Okay? It's true. P wave compress and expand materials as they move. It's tropa din. L waves move particles side to side. It's tropa din. Ano? S waves help scientist confirm the earth has a liquid out core. Ito na iyung trupa dined. And then body waves have a lower frequency than surface waves. It's false kasi mas mataas ang frequency ng body waves compared sa ah surface waves. Okay. So hopefully perfect sismic wave simulation. Okay. So

27:05 pwede niyo ito pong ipagawa sa mga bata, mga ma'am. Pwede niyo silang padalin ng slingy para mas ma-gets nila. Okay? So dito lang naman is iaano nila yung ide-demonstrate or simulate yung S p wave and then the love and the railing. Okay? So hindi ko na to aano mga sige skip na lang muna natin to. Ito yung ating rubric for earth scar guide. So proceed na tayo sa demonstration how water reacts to vibrations. Okay? So students will observe and understand how water responds to vibrations and soundes. Okay? So gagamitin natin shallow tray or dish. Okay? Pwede natin ong gawin. Magandang activity to mga man sir ano? So water speaker with a strong mask output music player or device to

27:51 play low frequency. Okay? So demonstration. Okayun po. Demonstrate how water reacts with vibrations. Okay? 'Di ba may mga vibrations naman yung nabo-pus yung sa mga speaker? Materials needed a shallow 3 dish clear if possible waters water speaker with a strong bass output bass output music player or device to play low frequency sounds and a round. Okay? Syempre baka may mag-spill ng water ano. So fill the shallow tree or dish with water until it's about half full. Place the tray on the top of the speaker. Ilagay sa top speaker. Connect the speaker to a music player or device. And then okay, choose a song or sound clip with a strong and steady bus light. Make sure it's something that produces low frequency vibrations. Play the selected sound

28:37 through the speaker at a moderate volume. Observe the surface of the water in the tree as the sound place. So makikita natin how the water will move. Okay? Nasa taas ng speaker. Okay? So yung speaker magpu-produce ng vibration. Let's uh imaginin natin yung speaker is yung earth. Okay? Nandun yung fault line. Magba-vibrate. Nandun yung focus. mare-release yung energy doon sa pataas doon sa water. Okay? So the simulation is a simulation on how much tsunami especially when the earthquake happened under water. Okay? So let's say na gawa na natin. What did the speaker produce that made the water move? Okay. The speaker produce sound, vapes or vibrations. This vibrations travel through the tray and into the water causing the water surface to ripple.

29:23 They may riple and move. Okay, what will happen if there are bigger vibrations produced? Okay, ifr are produced the water will move more vigorously, the ripples will become larger, okay, the water may splash. Okay? Kaya may rug tayo. And then the movement will be more notable. Is it possible for bodies of water to be moved by vibrations? Okay, yes, it is possible. Large vibrations such as those produced by earthquakes underwater volcanic eruptions or strong impacts like for example meteorite impacts okay can move large bodies of water. This is how tsunamis and large water waves can form. Okay? So tsunami simulation so ito yung

30:09 pwede na nating ipagawa to. Okay? Nasa sa inyo mga ma. Okay, skip ko na lang to ano. So before I proceed to the formative assessment, before ako mag-proceed sa formative assessment mga anak, I just like to discuss how tsunami occur ano? So paano ba nangyayari yung tsunami? Okay. So pag sinabi nating mga anak na tsunami is a series ano a series siya of very large ocean waves caused by sad movement of ocean floor. Okay? And then it is not a normal wave. Hindi yan yung normal wave mga anak. Okay? Kasi yan na yung ah normal wave na ang dahilan ay wind. Hindi yon. Okay. So yung ating tsunami is caused by powerful events under the sea like for example Earth fake. So why

30:55 does a tsunami happen? Bakit nangyayari yan? So a tsunami happens when a large amount of water is suddenly displaced. Okay? So the most common cause underwater earthquake. Okay? So when tectonic plates move or collide, okay the earth's grass shift lifting or dropping the ocean floor. Okay? Kasi meron din mga subduction ganon. So the sudden movement pushes a huge amount of water upward creating a giants. Okay? So yun po yung nagiging reason or causes rather. Okay? So hopefully naman ay maging maingat ano pag may mga lindol agad especially sa coastline or sa underwater yung mga nakatira sa coastline or shore line mag-evacuate na agad. Okay? So proceed tayo sa guide

31:43 question or sa formative assessment rather. Ayan. Okay. Which of the following statement best describes the motion of love waves during an earthquake? A. Love waves travel in a rolling motion parallel to the direction of wave propagation. B. Love waves travel in a rolling motion perpendicular to the direction of wave propagation. C love waves travel in compressional motion perpendicular to the direction of wave propagation. Or ded waves travel in a compressional motion parallel to the direction of wave propagation. So the answer is letter P. Ano? Love waves travel in a rolling motion perpendicular to the direction of wave propagation. Kumbaga um ah what do you call this? Like horizontal. Okay. And then side to

32:30 side nakaka-create ng perpendicular okay to the direction of the wave propagation. Okay? So sige next. Ito yung pinakamalapit actually na sagot. Okay kasi yung first one love waves travel rolling parallel hindi okay and then uh love waves travel hindi too compressional okay kasi ah hindi naman nagco-compress love wes trouble compressional hindi rin okay so how do earthquakes occuring underwater or along subduction zones contribute to the formation of tsunamis okay so the answer is letter a underwater earthquakes release energy that generates sismic waves which propagate through the water and create

33:15 what is the primary factor that determines the extent of of devastation caused by tsunamis on sheline communities okay the magnitude of the earthquake that trigger the tsunamic okay number four in what way the surface waves contribute to the destructive power of genamis okay it's seen a surface waves interact with the seafoor creating additional energy and increasing the height of tsunami weight Next, how can coastal communities mitigate the impact of tsunamis on their shoreline infrastructure? Okay, letter A. by constructing seawalls and leaves. Okay? To absorb the energy of tsunami wave. Sa amin may mga seawall pero yung mga seawall naman is may double double parts pwede sa tsunami and

34:01 then sa mga storm surge. Yung storm surge na sinasabi ko mga anak is in yung a series of waves din pero yun ay napo-produce ng typhoon or ng ating mga storms or tropical cyclopes. Ayan. So hopefully that you learn something today. Thank you so much. Grade 7. ।